<PAGE>   1
================================================================================


                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                        --------------------------------

                                    FORM 10-Q
       QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
                              EXCHANGE ACT OF 1934


                                   (MARK ONE)

[X]  QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE
     ACT OF 1934 FOR THE QUARTERLY PERIOD ENDED MARCH 31, 2000

[ ]  TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
     EXCHANGE ACT OF 1934

       FOR THE TRANSITION PERIOD FROM_____________________________________

                           COMMISSION FILE NO. 0-23311


                                RADIOLOGIX, INC.
             (Exact name of registrant as specified in its charter)

          DELAWARE                                             75-2648089
 (State or other jurisdiction                               (I.R.S. Employer
     of incorporation or                                     Identification)
       organization)

                                3600 CHASE TOWER
                                2200 ROSS AVENUE
                               DALLAS, TEXAS 75201
          (Address of principal executive offices, including zip code)

                                 (214) 303-2776
              (Registrant's telephone number, including area code)


         Indicate by check mark whether the registrant (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
registrant was required to file such reports), and (2) has been subject to such
filing requirements for the past 90 days.

                                Yes [X]  No [ ]

         Indicate the number of shares outstanding of each of the issuer's
classes of common stock, as of the latest practicable date.

             Class                                 Outstanding at May 12, 2000
             -----                                 ---------------------------
COMMON STOCK, $0.0001 PAR VALUE                              19,505,978 SHARES


================================================================================

<PAGE>   2







                                RADIOLOGIX, INC.

                                    FORM 10-Q

                                      INDEX

<TABLE>
<CAPTION>
FORM 10-Q ITEM                                                                                             PAGE
--------------                                                                                             ----
<S>                                                                                                        <C>
PART I. FINANCIAL INFORMATION

        Item 1. Financial Statements

                Consolidated Balance Sheets as of March 31, 2000 (Unaudited) and December 31, 1999 .....    1

                Consolidated Statements of Income (Unaudited) for the three months
                ended March 31, 2000 and 1999 ..........................................................    2

                Consolidated Statements of Cash Flows (Unaudited) for the three months
                ended March 31, 2000 and 1999 ..........................................................    3

                Notes to Consolidated Financial Statements .............................................    4

        Item 2. Management's Discussion and Analysis of Financial Condition and Results of Operations...    7

        Item 3. Quantitative and Qualitative Disclosures About Market Risk .............................   10

PART II. OTHER INFORMATION

        Item 1. Legal Proceedings ......................................................................   11

        Item 2. Changes in Securities and Use of Proceeds ..............................................   11

        Item 3. Defaults Upon Senior Securities ........................................................   11

        Item 4. Submission of Matters to a Vote of Security Holders ....................................   11

        Item 5. Other Information ......................................................................   11

        Item 6. Exhibits and Reports on Form 8-K .......................................................   11

SIGNATURES .............................................................................................   12
</TABLE>




<PAGE>   3


                        RADIOLOGIX, INC. AND SUBSIDIARIES

                           CONSOLIDATED BALANCE SHEETS
                                 (IN THOUSANDS)

                                     ASSETS

<TABLE>
<CAPTION>
                                                                      MARCH 31,      DECEMBER 31,
                                                                        2000              1999
                                                                    -------------    -------------
                                                                              (UNAUDITED)
<S>                                                                 <C>              <C>
CURRENT ASSETS:
     Cash and cash equivalents ..................................   $       8,021    $       4,302
     Accounts receivable, net of allowances .....................          69,571           61,762
     Due from affiliates ........................................          10,584            9,671
     Other current assets .......................................           9,717            9,812
                                                                    -------------    -------------
            Total current assets ................................          97,893           85,547
PROPERTY AND EQUIPMENT, net of accumulated depreciation .........          61,462           60,405
INVESTMENTS IN JOINT VENTURES ...................................           6,675            6,369
INTANGIBLE ASSETS, net ..........................................          92,303           86,443
DEFERRED FINANCING COSTS, net ...................................           3,898            3,942
OTHER ASSETS ....................................................           2,141            2,134
                                                                    -------------    -------------
            Total assets ........................................   $     264,372    $     244,840
                                                                    =============    =============

                       LIABILITES AND STOCKHOLDERS' EQUITY

CURRENT LIABILITIES:
     Accounts payable and accrued expenses ......................   $      18,405    $      16,902
     Accrued physician retention ................................           9,653            8,642
     Accrued salaries and benefits ..............................           4,005            4,985
     Current portion of long-term debt ..........................          33,427           22,608
     Current portion of capital lease obligations ...............           5,787            5,484
     Deferred income taxes ......................................           1,651            1,651
     Other current liabilities ..................................             135               94
                                                                    -------------    -------------
            Total current liabilities ...........................          73,063           60,366
DEFERRED INCOME TAXES ...........................................           2,336            2,336
LONG-TERM DEBT, net of current portion ..........................         144,836          141,992
CAPITAL LEASE OBLIGATIONS, net of current portion ...............          15,028           14,756
OTHER LIABILITIES ...............................................             143              717
                                                                    -------------    -------------
            Total liabilities ...................................         235,406          220,167

MINORITY INTERESTS IN CONSOLIDATED SUBSIDIARIES .................           1,465            1,250

STOCKHOLDERS' EQUITY:
     Common stock ...............................................               2                2
     Additional paid-in capital .................................            (582)            (590)
     Retained earnings ..........................................          28,081           24,011
                                                                    -------------    -------------
            Total stockholders' equity ..........................          27,501           23,423
                                                                    -------------    -------------
            Total liabilities and stockholders' equity ..........   $     264,372    $     244,840
                                                                    =============    =============
</TABLE>






                                       2

<PAGE>   4



                        RADIOLOGIX, INC. AND SUBSIDIARIES

                        CONSOLIDATED STATEMENTS OF INCOME
                        (IN THOUSANDS, EXCEPT SHARE DATA)



<TABLE>
<CAPTION>
                                                       FOR THE THREE MONTHS ENDED MARCH 31,
                                                            2000                  1999
                                                          -------------    -------------
                                                                   (UNAUDITED)
<S>                                                       <C>              <C>
SERVICE FEE REVENUES ..................................   $      59,251    $      43,232

COSTS AND EXPENSES:
    Salaries and benefits .............................          15,418           11,843
    Field supplies ....................................           3,160            2,480
    Field rent and lease expense ......................           7,071            3,823
    Other field expenses ..............................           9,837            6,672
    Bad debt expense ..................................           5,388            4,037
    Corporate general and administrative ..............           2,606            2,629
    Depreciation and amortization .....................           5,363            3,612
                                                          -------------    -------------
             Total costs and expenses .................          48,843           35,096
                                                          -------------    -------------

OPERATING INCOME ......................................          10,408            8,136

OTHER EXPENSES:
    Interest expense, net .............................           4,244            2,340
                                                          -------------    -------------
             Total other expenses .....................           4,244            2,340
                                                          -------------    -------------

INCOME BEFORE TAXES, MINORITY
INTERESTS IN CONSOLIDATED SUBSIDIARIES
AND EQUITY IN EARNINGS OF INVESTMENTS .................           6,164            5,796

EQUITY IN EARNINGS OF INVESTMENTS .....................             903              673

MINORITY INTERESTS IN INCOME OF
CONSOLIDATED SUBSIDIARIES .............................            (282)            (204)
                                                          -------------    -------------

INCOME BEFORE TAXES ...................................           6,785            6,265

INCOME TAX EXPENSE ....................................          (2,714)          (2,381)
                                                          -------------    -------------

NET INCOME ............................................   $       4,071    $       3,884
                                                          =============    =============

NET INCOME PER COMMON SHARE
    Basic .............................................   $        0.21    $        0.20
    Diluted ...........................................   $        0.20    $        0.20

WEIGHTED AVERAGE SHARES OUTSTANDING
    Basic .............................................      19,463,164       19,294,638
    Diluted ...........................................      22,084,280       19,730,139
</TABLE>




                                       2

<PAGE>   5



                        RADIOLOGIX, INC. AND SUBSIDIARIES

                      CONSOLIDATED STATEMENTS OF CASH FLOWS
                                 (IN THOUSANDS)




<TABLE>
<CAPTION>
                                                                            FOR THE THREE MONTHS ENDED MARCH 31,
                                                                                  2000             1999
                                                                              -------------    -------------
                                                                                        (UNAUDITED)
<S>                                                                           <C>              <C>
CASH FLOWS FROM OPERATING ACTIVITIES:

       Net income .........................................................   $       4,071    $       3,884
       Adjustments to reconcile net income to net cash
              provided by operating activities--
              Minority interests ..........................................             282              204
              Depreciation and amortization ...............................           5,363            3,612
              Equity in earnings of investments ...........................            (903)            (673)
              Changes in assets and liabilities
                     Accounts receivable, net .............................          (7,809)          (3,534)
                     Other receivables and other current assets ...........            (819)            (194)
                     Other assets .........................................              (7)            (177)
                     Accounts payable and accrued expenses ................           2,555              (90)
                     Accrued salaries and benefits ........................            (980)             738
                     Other liabilities ....................................            (575)             633
                                                                              -------------    -------------
                           Net cash provided by operating activities ......           1,178            4,403
                                                                              -------------    -------------

CASH FLOWS FROM INVESTING ACTIVITIES:
       Purchases of property and equipment ................................          (3,309)          (6,061)
       Cash paid for acquisitions .........................................          (7,020)          (4,461)
       Contributions to joint ventures ....................................             (42)             (50)
       Distributions from joint ventures ..................................             572               91
                                                                              -------------    -------------
                           Net cash used in investing activities ..........          (9,799)         (10,481)
                                                                              -------------    -------------

CASH FLOWS FROM FINANCING ACTIVITIES:
       Proceeds from issuance of long-term debt ...........................          14,000            4,477
       Payments on capital leases .........................................          (1,669)            (465)
       Other ..............................................................               9               --
                                                                              -------------    -------------
                           Net cash provided by financing activities ......          12,340            4,012
                                                                              -------------    -------------

NET INCREASE (DECREASE) IN CASH
AND CASH EQUIVALENTS ......................................................           3,719           (2,066)

CASH AND CASH EQUIVALENTS, beginning of period ............................           4,302            6,485
                                                                              -------------    -------------

CASH AND CASH EQUIVALENTS, end of period ..................................   $       8,021    $       4,419
                                                                              =============    =============
</TABLE>









                                       3
<PAGE>   6




                        RADIOLOGIX, INC. AND SUBSIDIARIES
                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS



         The accompanying consolidated unaudited financial statements have been
prepared by Radiologix, Inc., a Delaware corporation (together with its
subsidiaries, "Radiologix" or the "Company"), pursuant to the rules and
regulations of the Securities and Exchange Commission ("SEC"), and reflect all
adjustments (all of which are of a normal recurring nature) which, in the
opinion of management, are necessary for a fair statement of the results of the
interim periods presented. These financial statements do not include all
disclosures associated with the annual financial statements and, accordingly,
should be read in conjunction with the attached Management's Discussion and
Analysis of Financial Condition and Results of Operations and the consolidated
financial statements and notes thereto for the year ended December 31, 1999,
included in Radiologix's Form 10-K filed with the SEC on March 29, 2000.

1. DESCRIPTION OF BUSINESS:

         Radiologix, Inc. is a leading provider of radiology services in the
United States through its ownership and operation of technologically advanced,
multi-modality outpatient diagnostic imaging centers. As of March 31, 2000, the
Company operates 118 imaging centers located in 18 states and the District of
Columbia. The Company's full-service imaging centers typically offer such
imaging modalities as x-ray, magnetic resonance imaging ("MRI"), computed
tomography ("CT"), mammography, ultrasound, nuclear medicine and positron
emission tomography ("PET"), as well as general radiography and fluoroscopy. The
diagnostic images which result from these procedures and the radiology reports
based on the images enable ordering physicians to diagnose and manage diseases
and injuries more accurately and effectively than would be possible without such
clinical information. Ordering physicians rely extensively on this type of
diagnostic information in making health care treatment decisions. Radiologix's
imaging centers have concentrated geographic coverage in markets located in
California, Florida, Illinois, Kansas, Maryland, New York, Pennsylvania, Texas,
Virginia and Washington D.C.

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES:

Basis of Presentation

         The consolidated financial statements have been prepared on the accrual
basis of accounting and include the accounts of the Company and its
majority-owned subsidiaries. All intercompany accounts and transactions have
been eliminated in consolidation.

Service Fee Revenue

         Service fee revenue represents radiology practices' revenue less
amounts retained by radiology practices. The amounts retained by radiology
practices represents amounts paid to the physicians pursuant to the service
agreements between the Company and the radiology practices. Under the service
agreements, the Company provides each physician group with the facilities and
equipment used in its medical practice, assumes responsibility for the
management of the operations of the practice, and employs substantially all of
the non-physician personnel utilized by the group. Although the Company assists
in negotiating managed care contracts for the radiology practices, it assumes no
risk under these arrangements.

         The Company's service fee revenue is dependent upon the operating
results of the radiology practices. Where state law allows, service fees due
under the service agreements for the radiology practices are derived from two
distinct revenue streams: (1) a negotiated percentage (typically 20% to 30%) of
the adjusted professional revenues as defined in the service agreements; and (2)
100% of the adjusted technical revenues as defined in the service agreements. In
states where the law requires a flat fee structure, the Company has negotiated a
base service fee, which is equal to the fair market value of the services
provided under the service agreements and which is renegotiated each year to
equal the fair market value of the services provided under the service
agreements. The flat fee structure results in the Company receiving
substantially the same amount of service fee as it would have received under its
negotiated percentage fee structure. Adjusted professional revenues and adjusted
technical revenues are determined by deducting certain contractually agreed-upon
expenses (non-physician salaries and



                                       4

<PAGE>   7

benefits, rent, depreciation, insurance, interest and other physician costs)
from the radiology practices' revenue. Questar revenues are primarily derived
from technical revenues generated from those imaging centers.

         Service fee revenue consists of the following (in thousands):

<TABLE>
<CAPTION>
                                                       For the Three Months Ended March 31,
                                                                2000            1999
                                                           -------------   -------------
<S>                                                        <C>             <C>
Professional component .................................   $      13,752   $      12,863
Technical component ....................................          45,499          30,369
                                                           -------------   -------------
                                                           $      59,251   $      43,232
                                                           =============   =============
</TABLE>

3. EARNINGS PER SHARE:

         The Company adopted the Statement of Financial Accounting Standards
("SFAS") No. 128, "Earnings per Share" ("EPS") effective December 31, 1997. SFAS
No. 128 simplifies the computation of EPS by replacing the presentation of
primary EPS with a presentation of basic EPS. Basic EPS is calculated by
dividing income available to common stockholders by the weighted average number
of common shares outstanding during the period (including shares to be issued).
Options, warrants, and other potentially dilutive securities are excluded from
the calculation of basic EPS. Diluted EPS includes the options, warrants, and
other potentially dilutive securities that are excluded from basic EPS using the
treasury stock method to the extent that these securities are not anti-dilutive.
Diluted EPS also includes the effect of the convertible note using the "if
converted" method. For the quarter ended March 31, 2000, under the "if
converted" method, approximately $251,000 of tax-effected interest savings and
2,318,841 weighted average shares were included in the calculation of diluted
EPS as an addition to net income and weighted average shares outstanding,
respectively. For the quarters ended March 31, 1999 and 2000, 435,502 and
302,278 shares, respectively, related to stock options were included in diluted
EPS.


4. SEGMENT REPORTING:

         The Company has five reportable segments: Mid-Atlantic Region,
Northeastern Region, Central Region, Western Region and Questar. The Company's
reportable segments are strategic business units defined by management's
division of responsibilities. Each owns and operates imaging centers and (except
for Questar) provides management services to the radiology facilities within
their respective segments.

         The accounting policies of the segments are the same as those described
in the summary of significant accounting policies except that the Company does
not allocate taxes associated with income to any of the regions. They are
managed separately because each segment operates under different contractual
arrangements, providing service to a diverse mix of patients and payors.

                    FOR THE THREE MONTHS ENDED MARCH 31, 2000
                                 (IN THOUSANDS)

<TABLE>
<CAPTION>
                                 Mid-Atlantic     Northeastern         Central         Western
                                  Region (1)        Region (2)       Region (3)       Region (4)       Questar(5)         Total
                                 -------------    -------------    -------------    -------------    -------------    -------------
<S>                              <C>              <C>              <C>              <C>              <C>              <C>
Service fee revenue              $      23,053    $      15,095    $       6,958    $       7,461    $       6,684    $      59,251
Total operating expenses                15,515           10,689            4,341            5,284            5,045           40,874
                                 -------------    -------------    -------------    -------------    -------------    -------------
Segment contribution                     7,538            4,406            2,617            2,177            1,639           18,377
Contribution margin                         33%              29%              38%              29%              25%              31%
Depreciation and
    amortization expense                 1,714              774              318              617              667            4,090
Interest expense                           349              202               93              180              402            1,226
Segment profit                           5,852            3,429            2,516            1,379              505           13,681
Segment assets                          58,719           41,165           20,911           18,377           24,070          163,242
Expenditures for
   segment assets                        1,632              785              231              228              133            3,009
</TABLE>








                                       5

<PAGE>   8





                    FOR THE THREE MONTHS ENDED MARCH 31, 1999
                                 (IN THOUSANDS)

<TABLE>
<CAPTION>
                                 Mid-Atlantic     Northeastern       Central           Western
                                  Region (1)       Region (2)        Region (3)        Region (4)          Total
                                 -------------    -------------    -------------     -------------     -------------
<S>                              <C>              <C>              <C>               <C>               <C>
Service fee revenue ..........   $      17,884    $      13,650    $       5,500     $       6,199     $      43,232
Total operating expenses .....          12,190            9,130            3,296             4,241            28,856
                                 -------------    -------------    -------------     -------------     -------------
Segment contribution .........           5,694            4,520            2,204             1,958            14,376
Contribution margin ..........              32%              33%              40%               32%               33%
Depreciation and
    amortization expense .....           1,392              704              190               431             2,717
Interest expense .............             162              234               30               180               606
Segment profit ...............           4,440            3,582            2,154             1,347            11,523

Segment assets ...............          17,969           23,168           (2,290)           (3,681)           35,166
Expenditures for
   segment assets ............           3,077            1,052              819               766             5,714
</TABLE>


(1)  Includes the Mid-Atlantic Market.

(2)  Includes the Finger Lakes and Hudson Valley Markets.

(3)  Includes the South Texas, Treasure Coast and Northeast Kansas Markets.

(4)  Includes the Bay Area Market.

(5)  Includes 33 imaging centers as of March 31, 2000.

<TABLE>
<CAPTION>
Reconciliation of profits                                                2000            1999
                                                                    -------------    -------------
<S>                                                                 <C>              <C>
         Segment profit .........................................   $      13,681    $      11,523
         Unallocated amounts:
                  Corporate general and administrative ..........          (2,606)          (2,629)
                  Corporate depreciation and amortization .......          (1,273)            (895)
                  Corporate interest expense ....................          (3,017)          (1,734)
                                                                    -------------    -------------
         Income before taxes ....................................   $       6,785    $       6,265
                                                                    =============    =============



Reconciliation of assets and expenditures .......................            2000             1999
                                                                    -------------    -------------
Assets:
         Segment amounts ........................................   $     163,242    $      35,166
         Corporate assets (including intangible assets) .........         101,130          132,390
                                                                    -------------    -------------
         Total assets ...........................................   $     264,372    $     167,556
                                                                    =============    =============

Expenditures:
         Segment amounts ........................................   $       3,009    $       5,714
         Corporate expenditures .................................             300              347
                                                                    -------------    -------------
         Total expenditures .....................................   $       3,309    $       6,061
                                                                    =============    =============
</TABLE>


5. SUBSEQUENT EVENT:

         On April 5, 2000, the Company announced that it had received a
commitment letter from Credit Suisse First Boston for a $275 million credit
facility. This facility would replace the Company's current credit facility. The
transaction is expected to close in late June and is subject to normal due
diligence, the approval of definitive agreements by both parties and the
satisfaction of other customary conditions.

         Also, in connection with the notification by NASDAQ previously
discussed in the Company's 1999 Form 10-K, the Company's common stock began
trading on the American Stock Exchange (Amex) on May 10, 2000, under the symbol
"RGX".





                                       6
<PAGE>   9


ITEM 2. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND
        RESULTS OF OPERATIONS

         The following discussion of the results of operations and financial
condition of the Company should be read in conjunction with the Company's
consolidated financial statements and notes thereto included in the Annual
Report on Form 10-K for the year ended December 31, 1999, and with the
consolidated financial statements included in this Form 10-Q.

OVERVIEW

         The Company is a leading provider of radiology services in the United
States through its (i) ownership and operation of technologically advanced,
multi-modality diagnostic imaging centers and (ii) provision of administrative,
management and information services to certain radiology business partners. The
Company derives the majority of its service fee revenue from providing the
technical component of radiology services performed at the Company's
free-standing imaging facilities and pursuant to the Company's outsourced
hospital relationships. In addition, the Company also derives service fee
revenue from providing management services to radiology practices pursuant to
long-term service agreements.

         Radiologix's 118 owned or operated imaging centers are located in 18
states and the District of Columbia, with concentrated geographic coverage in
markets located in California, Florida, Illinois, Kansas, Maryland, New York,
Pennsylvania, Texas, Virginia and Washington D.C.


RESULTS OF OPERATIONS

Three Months Ended March 31, 2000

Service Fee Revenue

         Service fee revenue increased $16,019,000 or 37.1% in the first quarter
of 2000 to $59,251,000 from $43,232,000 in the first quarter of 1999. Of the
increase from 1999 to 2000, $8,147,000 resulted from increased business within
existing facilities (19.1% same store increase), $6,587,000 resulted from
practices acquired and developed in 1999, and $1,285,000 resulted from "tuck-in"
acquisitions of imaging centers in 1999 and 2000.

Salaries and Benefits

         Salaries and benefits increased $3,575,000 or 30.2% in the first
quarter of 2000 to $15,418,000 from $11,843,000 in the first quarter of 1999. Of
the increase from 1999 to 2000, $1,938,000 resulted from existing facilities,
$1,315,000 resulted from practices acquired and developed in 1999, and $322,000
resulted from "tuck-in" acquisitions of imaging centers in 1999 and 2000. As a
percentage of service fee revenue, these costs were 26.0% and 27.4% in 2000 and
1999, respectively.

Field Supplies

         Field supplies increased $680,000 or 27.4% in the first quarter of 2000
to $3,160,000 from $2,480,000 in the first quarter of 1999. Of the increase from
1999 to 2000, $145,000 resulted from existing facilities, $302,000 resulted from
practices acquired and developed in 1999, and $233,000 resulted from "tuck-in"
acquisitions of imaging centers in 1999 and 2000. As a percentage of service fee
revenue, these costs were 5.3% and 5.7% in 2000 and 1999, respectively.

Field Rent and Lease Expense

         Field rent and lease expense increased $3,248,000 or 85.0% in the first
quarter of 2000 to $7,071,000 from $3,823,000 in the first quarter of 1999. Of
the increase from 1999 to 2000, $1,525,000 resulted from existing facilities.
This increase is partially attributable to several MRI leases in the Northeast
region that are based on a per scan basis. As 1999 volume increased, equipment
lease expense increased due to per scan payment arrangements associated with
these higher-end modalities. An increase of $1,606,000 resulted from practices
acquired and






                                       7
<PAGE>   10


developed in 1999, and $117,000 resulted from "tuck-in" acquisitions of imaging
centers in 1999 and 2000. These costs also increased due to the Company's
sale-leaseback transaction completed December 30, 1999 (see 1999 Form 10-K). As
a percentage of service fee revenue, these costs were 11.9% and 8.8% in 2000 and
1999, respectively.

Other Field Expenses

            Other field expenses increased $3,165,000 or 47.4% in the first
quarter of 2000 to $9,837,000 from $6,672,000 in the first quarter of 1999. Of
the increase from 1999 to 2000, $1,899,000 resulted from existing facilities,
$1,170,000 resulted from practices acquired and developed in 1999, and $96,000
resulted from "tuck-in" acquisitions of imaging centers in 1999 and 2000. As a
percentage of service fee revenue, these costs were 16.6% and 15.4% in 2000 and
1999, respectively.

Bad Debt Expense

         Bad debt expense increased $1,351,000 or 33.5% in the first quarter
of 2000 to $5,388,000 from $4,037,000 in the first quarter of 1999. This
increase is primarily attributable to the increase in revenues. As a percentage
of service fee revenue, these costs were 9.1% and 9.3% in 2000 and 1999,
respectively.

Corporate General and Administrative

         Corporate general and administrative expense decreased $23,000 or 0.9%
in the first quarter of 2000 to $2,606,000 from $2,629,000 in the first quarter
of 1999. As a percentage of service fee revenue, these costs were 4.4% and 6.1%
in 2000 and 1999, respectively.

Depreciation and Amortization

         Depreciation and amortization increased $1,751,000 or 48.5% in the
first quarter of 2000 to $5,363,000 from $3,612,000 in the first quarter of
1999. This increase was principally due to amortization of goodwill resulting
from the Company's acquisition of additional practices and facilities. In
addition, the Company has continued to upgrade its radiology equipment resulting
in increased deprecation expense. These increases were partially offset due to
the Company's sale-leaseback transaction completed December 30, 1999 (see 1999
Form 10-K). As a percentage of service fee revenue, these costs were 9.1% and
8.4% in 2000 and 1999, respectively.

Interest Expense, net

         Interest expense, net increased $1,904,000 or 81.4% in the first
quarter of 2000 to $4,244,000 from $2,340,000 in the first quarter of 1999. As a
percentage of service fee revenue, these costs were 7.2% and 5.4% in 2000 and
1999, respectively. The increase as a percentage of service fee revenue is a
result of the Company's acquisitions throughout 1999, resulting in higher debt
levels.

Income Taxes

         The Company's effective tax rate for the first quarter of 2000 was
40.0%, an increase of 2% from the same period in 1999. This increase is
primarily due to the non-deductible amortization of goodwill and a shift in
state income taxes based on the Company's recent expansions.

Liquidity and Capital Resources

         At March 31, 2000, the Company had $24,830,000 in working capital, a
decrease of $351,000 from December 31, 1999. The Company's principal sources of
liquidity consist of (i) cash and cash equivalents aggregating $8,021,000, (ii)
net accounts receivable of $69,571,000, and (iii) approximately $3,500,000 in
borrowing capacity under the Company's bank credit facility (the "Credit
Facility").

         For the three months ended March 31, 2000, $1,178,000 was provided by
operations. Cash of $9,799,000 was used in investing activities in the first
three months of 2000, $7,020,000 of which was related to certain acquisitions,
$3,309,000 related to the purchase of property and equipment and $530,000 net
was received from joint ventures.




                                       8
<PAGE>   11


Cash of $12,340,000 was provided by financing activities in the first three
months of 2000, substantially all of which was provided under the Credit
Facility.

         For the three months ended March 31, 1999, $4,403,000 was provided by
operations. Cash of $10,481,000 was used in investing activities in the first
three months of 1999, $4,461,000 of which was related to certain acquisitions,
$6,601,000 related to the purchase of property and equipment and $41,000 net was
received from joint ventures. Cash of $4,012,000 was provided by financing
activities in the first three months of 1999, substantially all of which was
provided under the Credit Facility.

         On November 26, 1997, the Company entered into the Credit Facility. The
Credit Facility was amended May 19, 1998. The loan agreement provides for
revolving loans of up to $160,000,000 to be used by the Company for acquisitions
and general working capital needs. The Company may borrow, repay and reborrow
amounts during the first three years of the Credit Facility. Amounts outstanding
under the Credit Facility at the end of three years are required to be repaid in
quarterly installments of varying amounts commencing September 30, 2000.

         The Credit Facility expires and all loans thereunder mature on the
sixth anniversary of the closing date of the Credit Facility. Borrowings under
the Credit Facility at any time may not exceed the lesser of $160,000,000 or
3.25 times the consolidated EBITDA of the Company, giving pro forma effect to
acquisitions made with such borrowings. In accordance with the Credit Facility,
the Company's senior debt under all senior credit arrangements could not exceed
$207,500,000 at March 31, 2000. As of March 31, 2000, the Company had
outstanding borrowings of $156,500,000 under the Credit Facility and an
additional $21,763,000. At the Company's option, the interest rate is (i) an
adjusted LIBOR rate, plus an applicable margin which can vary from 1.5% to 2.5%
dependent on certain financial ratios or (ii) the prime rate, plus an applicable
margin which can vary from 0.5% to 1.5%. In each case, the applicable margin
varies based on financial ratios maintained by the Company. The Credit Facility
includes certain restrictive covenants including prohibitions on the payment of
dividends and the maintenance of certain financial ratios (including minimum
debt-service coverage and maximum debt-to-EBITDA coverage, as defined).
Borrowings under the Credit Facility are secured by all service agreements,
which the Company is, or becomes a party to, and a pledge of the stock of the
Company's subsidiaries. At March 31, 2000, the Company is in compliance with the
Credit Facility's restrictive covenants.

         On July 30, 1999, the Company entered into a $20,000,000 convertible
junior subordinated note (the "Note") in connection with the Securities Purchase
Agreement for the Questar Imaging, Inc. acquisition, effective August 1, 1999.
The Note matures July 31, 2009 and bears interest, payable quarterly in cash or
payment in kind securities, at 8.0%. The principal of the Note is convertible
into the Company's common stock at the price of $8.625 per share. If by the
second anniversary date of the Note the closing price of the Company's common
stock has not averaged $8.625 for forty five of the sixty day determination
period (the "Market Price Event"), the base conversion price will be reset at
87.19% of the initial conversion price. If by the third or fourth anniversary
date of the Note the Market Price Event has not occurred, the interest rate will
be increased to 8.25% and 8.5%, respectively.

         The Securities Purchase Agreement includes certain restrictive
covenants including prohibitions on the payment of dividends, the reservation of
unissued common stock pending conversion or exercise of the Note, and the
maintenance of certain financial ratios (including maximum interest coverage and
leverage ratios, as defined). At March 31, 2000, the Company is in compliance
with the Note's restrictive covenants.

         On April 5, 2000, the Company announced that it had received a
commitment letter from Credit Suisse First Boston for a $275 million credit
facility. This facility would replace the Credit Facility. The transaction is
expected to close in late June and is subject to normal due diligence, approval
of definitive agreements by both parties and the satisfaction of other customary
conditions. Management believes the completion of this transaction will provide
the Company with the capital necessary to facilitate its growth strategy for
2000 and beyond and to meet its liquidity needs for the foreseeable future.





                                       9
<PAGE>   12


Forward-Looking Statements

            This report contains or may contain forward-looking statements
within the meaning of Section 21E of the Securities Exchange Act of 1934
including statements of the Company's and management's expectations, intentions,
plans and beliefs, including those contained in or implied by "Management's
Discussion and Analysis of Financial Condition and Results of Operations." These
forward-looking statements, as defined in Section 21E of the Securities Exchange
Act of 1934, are dependent on certain events, risks and uncertainties that may
be outside of the Company's control. These forward-looking statements may
include statements of management's plans and objectives for the Company's future
operations and statements of future economic performance; the Company's capital
budget and future capital requirements, and the Company's meeting its future
capital needs; and the assumptions described in this report underlying such
forward-looking statements. Actual results and developments could differ
materially from those expressed in or implied by such statements due to a number
of factors, including, without limitation, those described in the context of
such forward-looking statements.

ITEM 3. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

         The Company's exposure to market risk for changes in interest rates
relates primarily to the Company's cash equivalents and its Credit Facility.







                                       10
<PAGE>   13


                           PART II: OTHER INFORMATION

ITEM 1. LEGAL PROCEEDINGS

            The Company is not currently subject to any material litigation or,
to the Company's knowledge, is any material litigation threatened against the
Company other than routine litigation arising in the ordinary course of
business, which litigation is expected to be covered by liability insurance and
all of which is not expected to have a material adverse effect on the Company's
business, financial condition or results of operations. There can be no
assurance that the Company will not subsequently be named as a defendant in
additional lawsuits.

            There can be no assurance that the Company will not be named as a
defendant in lawsuits for matters arising out of events that occurred prior to
the acquisition of the related radiology practices or other acquisitions. Each
practice or the seller, as applicable, has retained responsibility for, and /or
agreed to indemnify the Company in full against, certain liabilities associated
with these lawsuits. In the event the Company is named as a party in any of
these lawsuits, or a monetary judgment is entered against the Company and
indemnification is unavailable for any reason, the Company's business, financial
condition and results of operations could be materially adversely affected.

ITEM 2. CHANGES IN SECURITIES AND USE OF PROCEEDS

            Not Applicable

ITEM 3. DEFAULTS UPON SENIOR SECURITIES

            Not Applicable

ITEM 4. SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS

            Not Applicable

ITEM 5. OTHER INFORMATION

            Not Applicable

ITEM 6. EXHIBITS AND REPORTS ON FORM 8-K

  (a) Exhibits. See Index to Exhibits following signatures.

  (b) Reports on Form 8-K





                                       11
<PAGE>   14




                                   SIGNATURES

         Pursuant to the requirements of the Securities Exchange Act of 1934,
the registrant has duly caused this report to be signed on its behalf by the
undersigned thereunto duly authorized.


                                          RADIOLOGIX, INC.


Date: May 15, 2000                        /s/ MARK L. WAGAR
                                          --------------------------------
                                          Mark L. Wagar
                                          Chairman of the Board and
                                          Chief Executive Officer
                                          (Principal Executive Officer)




Date: May 15, 2000                         /s/ DAVID W. YOUNG
                                          --------------------------------
                                          David W. Young
                                          Vice President of Finance,
                                          Treasurer and Controller
                                          (Principal Accounting Officer)


                                       12
<PAGE>   15



                                INDEX TO EXHIBITS

<TABLE>
<CAPTION>

       EXHIBIT
       NUMBER                        DESCRIPTION
       -------                       -----------

<S>                    <C>
         2.1           Agreement and Plan of Reorganization and Merger, dated
                       June 27, 1997 by and among American Physician Partners,
                       Inc., Carroll Imaging Associates, P.A., Diagnostic
                       Imaging Associates, P.A., Drs. Copeland, Hyman and
                       Shackman, P.A., Drs. Decarlo, Lyon, Hearn & Pazourek,
                       P.A., Drs. Thomas, Wallop, Kim & Lewis, P.A., Harbor
                       Radiologists, P.A., and Perilla, Syndler & Associates,
                       P.A. **

         2.2           Agreement and Plan of Reorganization and Merger, dated
                       June 27, 1997 by and between American Physician Partners,
                       Inc., Radiology and Nuclear Medicine, A Professional
                       Association. **

         2.3           Agreement and Plan of Reorganization and Merger, dated
                       June 27, 1997 by and between American Physician Partners,
                       Inc., and Mid Rockland Imaging Associates, P.C.**

         2.4           Agreement and Plan of Reorganization and Merger, dated
                       June 27, 1997 by and between American Physician Partners,
                       Inc., and Rockland Radiological Group, P.C.**

         2.5           Agreement and Plan of Reorganization and Merger, dated
                       June 27, 1997 by and between American Physician Partners,
                       Inc., and Advanced Imaging of Orange County, P.C. **

         2.6           Agreement and Plan of Reorganization and Merger, dated
                       June 27, 1997 by and between American Physician Partners,
                       Inc., and Central Imaging Associates, P.C. **

         2.7           Agreement and Plan of Reorganization and Merger, dated
                       June 27, 1997 by and between American Physician Partners,
                       Inc., and Nyack Magnetic Resonance Imaging, P.C. **

         2.8           Agreement and Plan of Reorganization and Merger, dated
                       June 27, 1997 by and between American Physician Partners,
                       Inc., and Pelham Imaging Associates, P.C. **

         2.9           Agreement and Plan of Reorganization and Merger, dated
                       June 27, 1997 by and between American Physician Partners,
                       Inc., and Women's Imaging Consultants, P.C. **

         2.10          Agreement and Plan of Reorganization and Merger, dated
                       June 27, 1997 by and between American Physician Partners,
                       Inc., and Pacific Imaging Consultants, A Medical Group,
                       Inc. **

         2.11          Agreement and Plan of Reorganization and Merger, dated
                       June 27, 1997 by and between American Physician Partners,
                       Inc., and Total Medical Imaging, Inc.**

         2.12          Agreement and Plan of Reorganization and Merger, dated
                       June 27, 1997 by and between American Physician Partners,
                       Inc., and Valley Radiologists Medical Group, Inc. **

         2.13          Agreement and Plan of Reorganization and Merger, dated
                       June 27, 1997 by and between American Physician Partners,
                       Inc., and The Ide Group, P.C. **
</TABLE>




<PAGE>   16

<TABLE>

<S>                    <C>
         2.14          Agreement and Plan of Reorganization and Merger, dated
                       June 27, 1997 by and between American Physician Partners,
                       Inc., and M&S X-Ray Associates, P.A. **

         2.15          Agreement and Plan of Reorganization and Merger, dated
                       June 27, 1997 by and between American Physician Partners,
                       Inc., and South Texas MR, Inc. **

         2.16          Agreement and Plan of Exchange, dated June 27, 1997 by
                       and between American Physician Partners, Inc., and San
                       Antonio MR, Inc. **

         2.17          Agreement and Plan of Exchange, dated June 27, 1997 by
                       and among American Physician Partners, Inc., Lexington
                       MR, Ltd. and the Sellers. **

         2.18          Agreement and Plan of Exchange, dated June 27, 1997 by
                       and among American Physician Partners, Inc., Madison
                       Square Joint Venture and the Sellers. **

         2.19          Agreement and Plan of Exchange, dated June 27, 1997 by
                       and among American Physician Partners, Inc., South Texas
                       No. 1 MRI Limited Partnership, a Texas limited
                       partnership, and the Sellers. **

         2.20          Agreement and Plan of Exchange, dated June 27, 1997 by
                       and among American Physician Partners, Inc., San Antonio
                       MRI Partnership No. 2 Ltd., a Texas limited partnership,
                       and the Sellers**

         2.21          Agreement and Plan of Exchange, dated June 27, 1997 by
                       and between American Physician Partners, Inc., and the
                       Sellers **

         2.22          Amendment No. 1 to the Agreement and Plan of
                       Reorganization and Merger, dated as of September 30,
                       1997, by and among American Physician Partners, Inc.,
                       Carroll Imaging Associates, P.A., Diagnostic Imaging
                       Associates, P.A., Drs. Thomas, Wallop, Kim & Lewis, P.A.,
                       Drs. Copeland, Hyman & Shackman, P.A., Drs. DeCarlo,
                       Lyon, Hearn & Pazourek, P.A., Harbor Radiologists, P.A.,
                       and Perilla, Sindler & Associates, P.A.**

         2.23          Amendment No. 1 to the Agreement and Plan of
                       Reorganization and Merger, dated as of September 30,
                       1997, by and between American Physician Partners, Inc.,
                       and Radiology and Nuclear Medicine, A Professional
                       Association.**

         2.24          Amendment No. 1 to the Agreement and Plan of
                       Reorganization and Merger, dated as of September 30,
                       1997, by and between American Physician Partners, Inc.,
                       and Mid Rockland Imaging Associates, P.C.**

         2.25          Amendment No. 1 to the Agreement and Plan of
                       Reorganization and Merger, dated as of September 30,
                       1997, by and between American Physician Partners, Inc.,
                       and Rockland Radiological Group, P.C.**
</TABLE>




<PAGE>   17


<TABLE>

<S>                    <C>
         2.26          Amendment No. 1 to the Agreement and Plan of
                       Reorganization and Merger, dated as of September 30,
                       1997, by and between American Physician Partners, Inc.,
                       and Advanced Imaging of Orange County, P.C.**

         2.27          Amendment No. 1 to the Agreement and Plan of
                       Reorganization and Merger, dated as of September 30,
                       1997, by and between American Physician Partners, Inc.,
                       and Central Imaging Associates, P.C.**

         2.28          Amendment No. 1 to the Agreement and Plan of
                       Reorganization and Merger, dated as of September 30,
                       1997, by and between American Physician Partners, Inc.,
                       and Nyack Magnetic Resonance Imaging, P.C.**

         2.29          Amendment No. 1 to the Agreement and Plan of
                       Reorganization and Merger, dated as of September 30,
                       1997, by and between American Physician Partners, Inc.,
                       and Pelham Imaging Associates, P.C.**

         2.30          Amendment No. 1 to the Agreement and Plan of
                       Reorganization and Merger, dated as of September 30,
                       1997, by and between American Physician Partners, Inc.,
                       and Women's Imaging Consultants, P.C.**

         2.31          Amendment No. 1 to the Agreement and Plan of
                       Reorganization and Merger, dated as of September 30,
                       1997, by and between American Physician Partners, Inc.,
                       and Pacific Imaging Consultants, A Medical Group, Inc.**

         2.32          Amendment No. 1 to the Agreement and Plan of
                       Reorganization and Merger, dated as of September 30,
                       1997, by and between American Physician Partners, Inc.,
                       and Total Medical Imaging, Inc.**

         2.33          Amendment No. 1 to the Agreement and Plan of
                       Reorganization and Merger, dated as of September 30,
                       1997, by and between American Physician Partners, Inc.,
                       and Valley Radiologists Medical Group, Inc.**

         2.34          Amendment No. 1 to the Agreement and Plan of
                       Reorganization and Merger, dated as of September 30,
                       1997, by and between American Physician Partners, Inc.,
                       and The Ide Group, P.C.**

         2.35          Amendment No. 1 to the Agreement and Plan of
                       Reorganization and Merger, dated as of September 30,
                       1997, by and between American Physician Partners, Inc.,
                       and M & S X-Ray Associates, P.A.**

         2.36          Amendment No. 1 to the Agreement and Plan of
                       Reorganization and Merger, dated as of September 30,
                       1997, by and between American Physician Partners, Inc.,
                       and South Texas MR, Inc.**

         2.37          Amendment No. 1 to the Agreement and Plan of
                       Reorganization and Merger, dated as of September 30,
                       1997, by and between American Physician Partners, Inc.,
                       and San Antonio MR, Inc.**

         2.38          Amendment No. 1 to the Agreement and Plan of Exchange,
                       dated September 30, 1997, by and between American
                       Physician Partners, Inc., and Lexington MR, Ltd.**

         2.39          Amendment No. 1 to the Agreement and Plan of Exchange,
                       dated September 30, 1997, by and between American
                       Physician Partners, Inc., and Madison Square Joint
                       Venture.**
</TABLE>

<PAGE>   18

<TABLE>

<S>                    <C>
         2.40          Amendment No. 1 to the Agreement and Plan of Exchange,
                       dated September 30, 1997, by and between American
                       Physician Partners, Inc., and South Texas No. 1 MRI
                       Limited Partnership.**

         2.41          Amendment No. 1 to the Agreement and Plan of Exchange,
                       dated September 30, 1997, by and between American
                       Physician Partners, Inc., and San Antonio MRI Partnership
                       No. 2, Ltd.**

         2.42          Asset Purchase Agreement, dated as of January 1, 1998, by
                       and among American Physician Partners, Inc., Community
                       Radiology Associates, Inc., Drs. Korsower and Pion
                       Radiology, P.A., and the Principal Stockholders ****

         2.43          Asset Purchase Agreement, dated as of January 12, 1998,
                       by and among American Physician Partners, Inc., Valley
                       Imaging Partners, Inc., Questar Imaging, Inc. and Questar
                       Imaging VR, Inc. ****

         2.44          Asset Purchase Agreement, dated as of January 23, 1998,
                       by and among American Physician Partners, Inc., Valley
                       Imaging Partners, Inc., PAL Imaging Corp. and the
                       Principal Stockholders ****

         2.45          Asset Purchase Agreement, dated as of April 1, 1998, by
                       and among American Physician Partners, Inc., Treasure
                       Coast Imaging Partners, Inc. and Radiology Imaging
                       Associates, Basilico, Gallagher and Raffa, M.D., P.A. and
                       Robert F. Basilico, M.D., Edward Gallagher, M.D., R.J.
                       Raffa, M.D., Joseph T. Charles, M.D., Alex N. Vennos,
                       M.D., and Robin J. Connolly, M.D.*****

         2.46          Asset Purchase Agreement, dated as of April 1, 1998, by
                       and among American Physician Partners, Inc., Treasure
                       Coast Imaging Partners, Inc. and St. Lucie Imaging and
                       Breast Center, Inc. and Robert F. Basilico, M.D., Edward
                       Gallagher, M.D., R.J. Raffa, M.D., Joseph T. Charles,
                       M.D., Alex N. Vennos, M.D., and Robin J. Connolly,
                       M.D.*****

         2.47          Asset Purchase Agreement, dated as of April 28, 1998, by
                       and among American Physician Partners, Inc., Valley
                       Imaging Partners, Inc., LXL, Ltd. and the Partners of
                       LXL, Ltd.*****

         2.48          Asset Purchase Agreement, dated as of June 1, 1998, by
                       and among American Physician Partners, Inc., Mid Rockland
                       Imaging Partners, Inc., Empire State Imaging Partners,
                       Inc., RF Management Corp. and Modern Medical Modalities
                       Corporation*****

         2.49          Asset Purchase Agreement, dated as of June 23, 1998, by
                       and among American Physician Partners, Inc., Valley
                       Imaging Partners, Inc., Brewster Imaging Center, Inc. and
                       Each Principal Stockholder*****

         2.50          Asset Purchase Agreement, dated as of June 29, 1998, by
                       and among American Physician Partners, Inc., Valley
                       Imaging Partners, Inc. and Bryan M. Shieman, M.D., a sole
                       proprietorship d/b/a El Camino Center for Osteoporosis
                       and/or ECOO II*****
</TABLE>

<PAGE>   19

<TABLE>
<S>                    <C>
         2.51          Stock Purchase Agreement, dated September 1, 1998, by and
                       among American Physician Partners, Inc., WB&A Imaging
                       Partners, Inc. and Vimla Bhooshan, M.D., John B.
                       DeGrazia, M.D., Edwin Goldstein, M.D., Paul T. Lubar,
                       M.D., Calvin D. Neithamer, M.D., William P. O'Grady,
                       M.D., Robert A. Olshaker, M.D., Stanley M. Perl, M.D.,
                       Michael S. Usher, M.D., Alan B. Kronthal, M.D., Steven A.
                       Meyers, M.D., Victor A. Bracey, M.D. and Larry W.
                       Busching ******

         2.52          Asset Purchase Agreement, dated September 1, 1998, by and
                       among American Physician Partners, Inc., Ormond Imaging
                       Partners, Inc., Magnetic Resonance Imaging Associates
                       Limited Partnership and Paul T. Lubar, Stanley M. Perl,
                       Michael S. Usher, John B. DeGrazia, Larry W. Busching,
                       Vimla Bhooshan, William P. O'Grady, Robert A. Olshaker,
                       and Calvin D. Neithamer ******

         2.53          Asset Purchase Agreement, dated September 1, 1998, by and
                       among American Physician Partners, Inc., Ormond Imaging
                       Partners, Inc., Duke Associates Limited Partnership and
                       Paul T. Lubar, Stanley M. Perl, Michael S. Usher, John B.
                       DeGrazia, Larry W. Busching, Vimla Bhooshan, William P.
                       O'Grady, Edwin Goldstein, Robert A. Olshaker, Calvin D.
                       Neithamer and Alan J. Kronthal ******

         2.54          Stock Purchase Agreement effective as of August 1, 1999
                       by and among American Physician Partners, Inc., Questar
                       Imaging, Inc. and the shareholders of Questar Imaging,
                       Inc.********

         3.1           Restated Certificate of Incorporation of American
                       Physician Partners, Inc.***

         3.2           Amended and Restated Bylaws of American Physician
                       Partners, Inc.***

         3.3           Amendment to Restated Certificate of Incorporation of
                       American Physician Partners, Inc.*********

         3.4           Amendment to Restated Bylaws of American Physician
                       Partners, Inc.*********

         4.1           Form of certificate evidencing ownership of Common Stock
                       of American Physician Partners, Inc.***

         4.2           Form of Convertible Promissory Note of American Physician
                       Partners, Inc.**

         4.3           Securities Purchase Agreement dated as of August 3, 1999
                       by and between American Physician Partners, Inc. and BT
                       Capital Partners SBIC, L.P.********

         4.4           Convertible Junior Subordinated Promisory Note dated
                       August 1, 1999 issued to BT Capital Partners SBIC,
                       L.P.********

         10.1          American Physician Partners, Inc. 1996 Stock Option
                       Plan.**

         10.2          Employment Agreement between American Physician Partners,
                       Inc. and Gregory L. Solomon.**

         10.3          Employment Agreement between American Physician Partners,
                       Inc. and Mark S. Martin.**
</TABLE>



<PAGE>   20

<TABLE>

<S>                    <C>
         10.4          Employment Agreement between American Physician Partners,
                       Inc. and Sami S. Abbasi.**

         10.5          Employment Agreement between American Physician Partners,
                       Inc. and Paul M. Jolas.**

         10.6          Form of Indemnification Agreement for certain Directors
                       and Officers.***

         10.7          Form of Registration Rights Agreement.**

         10.8          Service Agreement dated November 26, 1997, by and among
                       American Physician Partners, Inc., APPI-Advanced
                       Radiology, Inc. and Carroll Imaging Associates, P.A.,
                       Diagnostic Imaging Associates, P.A., Drs. Thomas, Wallop,
                       Kim & Lewis, P.A., Drs. Copeland, Hyman and Shackman,
                       P.A., Drs. Decarlo, Lyon, Hearn & Pazourek, P.A., Harbor
                       Radiologists, P.A., Perilla, Sindler & Associates, P.A.**

         10.9          Service Agreement dated November 26, 1997, by and among
                       American Physician Partners, Inc., Ide Admin Corp. and
                       Ide Imaging Group, P.C.**

         10.10         Service Agreement dated November 26, 1997, by and among
                       American Physician Partners, Inc., M & S X-Ray
                       Associates, P.A. and M&S Imaging Associates, P.A.**

         10.11         Service Agreement dated November 26, 1997, by and among
                       American Physician Partners, Inc., Rockland Radiological
                       Group, P.C. and The Greater Rockland Radiological Group,
                       P.C.**

         10.12         Service Agreement dated November , by and among American
                       Physician Partners, Inc., Advanced Imaging of Orange
                       County, P.C. and The Greater Rockland Radiological Group,
                       P.C.**

         10.13         Service Agreement dated November 26, 1997, by and among
                       American Physician Partners, Inc., Central Imaging
                       Associates, P.C. and The Greater Rockland Radiological
                       Group, P.C.**

         10.14         Service Agreement dated November 26, 1997, by and among
                       American Physician Partners, Inc., Nyack Magnetic
                       Resonance Imaging, P.C. and The Greater Rockland
                       Radiological Group, P.C.**

         10.15         Service Agreement dated November 26, 1997, by and among
                       American Physician Partners, Inc., Pelham Imaging
                       Associates, P.C. and The Greater Rockland Radiological
                       Group, P.C.**

         10.16         Service Agreement dated November 26, 1997, by and among
                       American Physician Partners, Inc., Women's Imaging
                       Consultants, P.C. and The Greater Rockland Radiological
                       Group, P.C.**

         10.17         Service Agreement dated November 26, 1997, by and among
                       American Physician Partners, Inc., APPI-Pacific Imaging
                       Inc. and PIC Medical Group, Inc.**

         10.18         Service Agreement dated November 26, 1997, by and among
                       American Physician Partners, Inc., Radiology and Nuclear
                       Medicine, a Professional Association and RNM L.L.C.**
</TABLE>


<PAGE>   21

<TABLE>
<S>                    <C>
         10.19         Service Agreement dated November 26, 1997, by and among
                       American Physician Partners, Inc., APPI-Valley Radiology,
                       Inc. and Valley Radiology Medical Associates, Inc.**

         10.20         Consulting Agreement between American Physician Partners,
                       Inc. and Michael L. Sherman, M.D.***

         10.21         Office Building Lease Agreement between Dallas Main
                       Center Limited Partnership and American Physician
                       Partners, Inc.***

         10.22         First Amendment to Office Building Lease Agreement
                       between Dallas Main Center Limited Partnership and
                       American Physician Partners, Inc.***

         10.24         Consulting Agreement between American Physician Partners,
                       Inc. and Lawrence R. Muroff, M.D.***

         10.25         Side Letter dated November 12, 1997 by and between
                       American Physician Partners, Inc. and Lawrence Muroff,
                       M.D.***

         10.26         Side Letter dated November 12, 1997 by and between
                       American Physician Partners, Inc. and Mark Martin.***

         10.27         Side Letter dated November 12, 1997 by and between
                       American Physician Partners, Inc. and Sami Abbasi.***

         10.28         Side Letter dated November 12, 1997 by and between
                       American Physician Partners, Inc. and Gregory L.
                       Solomon.***

         10.29         First Amendment to Consulting Agreement between American
                       Physician Partners, Inc. and Lawrence R. Muroff, M.D.***

         10.30         Side Letter dated November 12, 1997 by and between
                       American Physician Partners, Inc. and Michael Sherman,
                       M.D.***

         10.31         Side Letter dated November 12, 1997 by and between
                       American Physician Partners, Inc. and Paul M. Jolas.***

         10.32         Side Letter dated November 12, 1997 by and between
                       American Physician Partners, Inc. and Derace Schaffer,
                       M.D.***

         10.33         Side Letter dated November 12, 1997 by and between
                       American Physician Partners, Inc. and John Pappajohn.***

         10.34         Side Letter dated November 12, 1997 by and between
                       American Physician Partners, Inc. and Mary Pappajohn.***

         10.35         Side Letter dated November 12, 1997 by and between
                       American Physician Partners, Inc. and Thebes Ltd.***

         10.36         Side Letter dated November 12, 1997 by and between
                       American Physician Partners, Inc. and Halkis Ltd.***

         10.37         Service Agreement dated January 1, 1998, by and among
                       American Physician Partners, Inc., Community Imaging
                       Partners, Inc., Community Radiology Associates, Inc. and
                       Drs. Korsower and Pion Radiology, P.A.****
</TABLE>


<PAGE>   22

<TABLE>

<S>                    <C>
         10.38         Service Agreement dated April 1, 1998, by and among
                       American Physician Partners, Inc., Treasure Coast Imaging
                       Partners, Inc. and Radiology Imaging Associates -
                       Basilico, Gallagher & Raffa, M.D., P.A. *****

         10.39         First Amendment to Credit Agreement and Consent dated May
                       19, 1998, by and among American Physician Partners, Inc.,
                       General Electric Capital Corporation and the other credit
                       parties signatory thereto*****

         10.40         Employment Agreement between American Physician Partners,
                       Inc. and Mark L. Wagar*****

         10.41         Service Agreement dated September 1, 1998, by and among
                       American Physician Partners, Inc., WB&A Imaging Partners,
                       Inc. and WB&A Imaging, P.C. ******

         10.42         Office Building Lease Agreement between The
                       Equitable-Nissei Dallas Company and Fibreboard
                       Corporation ******

         10.43         Office Building Sublease Agreement by and between
                       Fibreboard Corporation and American Physician Partners,
                       Inc. ******

         10.44         First Amendment to Employment Agreement between American
                       Physician Partners, Inc. and Mark L. Wagar *******

         10.45         First Amendment to Employment Agreement between American
                       Physician Partners, Inc. and Mark S. Martin *******

         10.46         First Amendment to Employment Agreement between American
                       Physician Partners, Inc. and Sami S. Abbasi *******

         10.47         First Amendment to Employment Agreement between American
                       Physician Partners, Inc. and Paul M. Jolas *******

         10.48         Amendment No. 1 to American Physician Partners, Inc. 1996
                       Stock Option Plan ********

         10.49         Amendment No. 2 of Employment Agreement between
                       Radiologix, Inc. and Mark S. Martin*

         27            Financial Data Schedule *

         99.1          Press Release issued by Radiologix, Inc. on September 24,
                       1999 announcing its change of corporate name from
                       American Physician Partners, Inc. **********

         99.2          Certificate of Ownership and Merger of Radiologix, Inc.
                       with and into American Physician Partners, Inc.
                       **********
</TABLE>
--------------------
         *             Filed herewith.

<PAGE>   23

         **            Incorporated by reference to the corresponding Exhibit
                       number to the registrant's Registration Statement No.
                       333-31611 on Form S-4.

         ***           Incorporated by reference to the corresponding Exhibit
                       number to the registrant's Registration Statement No.
                       333-30205 on Form S-1.

         ****          Incorporated by reference to the corresponding Exhibit
                       number to the registrant's Form 10-Q filed on May 15,
                       1998.

         *****         Incorporated by reference to the corresponding Exhibit
                       number to the registrant's Form 10-Q filed on August 14,
                       1998.

         ******        Incorporated by reference to the corresponding Exhibit
                       number to the registrant's Form 10-Q filed on November
                       13, 1998.

         *******       Incorporated by reference to the corresponding Exhibit
                       number to the registrant's Form 10-Q filed on May 17,
                       1999.

         ********      Incorporated by reference to the corresponding Exhibit
                       number to the Registrant's Form 8-K filed on August 3,
                       1999.

         *********     Incorporated by reference to the corresponding Exhibit
                       number to the Registrant's Form 10-Q filed on August 16,
                       1999.

         **********    Incorporated by reference to the corresponding Exhibit
                       number to the Registrant's Form 8-K filed on September
                       24, 1999.