<PAGE>
 
                                   FORM 10-Q

                      SECURITIES AND EXCHANGE COMMISSION

                            Washington, D.C. 20549


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

            For the quarterly period ended           June 30, 1998
                                          -----------------------------------

                                      OR

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

         For the transition period from _____________ to _____________

                         Commission file number 1-9983

                           OEC MEDICAL SYSTEMS, INC.
                                 (Registrant)

                     Incorporated in the State of Delaware

               I.R.S. Employer Identification Number 94-2538512


             384 Wright Brothers Drive, Salt Lake City, Utah 84116
                   (Address of Principal Executive Offices)


                          Telephone:  (801) 328-9300

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 requirements
for the past 90 days.

                         Yes  X                No
                            -----                -----    

As of July 31, 1998, there were 12,662,426 shares of Common Stock ($.01 par
value) outstanding.
<PAGE>
 
PART I.           Financial Information
ITEM 1.           Financial Statements
                  
                           OEC MEDICAL SYSTEMS, INC.
                     CONSOLIDATED STATEMENTS OF OPERATIONS
                                  (unaudited)
           FOR THE QUARTER & SIX MONTHS ENDED JUNE 30, 1998 AND 1997
                   (In thousands, except per share amounts)

<TABLE>
<CAPTION>
 
 
                                       Quarter Ended June 30,    Six Months Ended June 30,
                                         1998         1997          1998           1997
                                      -----------  -----------  -------------  ------------
<S>                                   <C>          <C>          <C>            <C>
 
Net sales
  Product                                $39,622      $34,570        $75,961       $62,690
 Service                                   5,925        4,310         11,181         8,504
                                         -------      -------        -------       -------
  Total net sales                         45,547       38,880         87,142        71,194
                                         -------      -------        -------       -------
 
Cost of sales
 Product                                  21,961       19,783         42,180        36,417
 Service                                   4,233        3,134          8,211         6,117
                                         -------      -------        -------       -------
  Total cost of sales                     26,194       22,917         50,391        42,534
                                         -------      -------        -------       -------
  Gross margin                            19,353       15,963         36,751        28,660
                                         -------      -------        -------       -------
 
Operating expenses
 Research and development                  3,274        2,894          6,284         5,519
 Marketing and sales                       7,840        6,621         15,163        11,904
 Administrative, general and other         2,428        2,315          4,723         3,978
                                         -------      -------        -------       -------
  Total operating expenses                13,542       11,830         26,170        21,401
                                         -------      -------        -------       -------
 
Operating income                           5,811        4,133         10,581         7,259
 
Interest income                              223          202            490           457
Interest expense                             (69)          (2)          (145)           (5)
                                         -------      -------        -------       -------
 
Income before income taxes                 5,965        4,333         10,926         7,711
 
Income tax expense                         2,090        1,590          3,806         2,667
                                         -------      -------        -------       -------
Net income                               $ 3,875      $ 2,743        $ 7,120       $ 5,044
                                         =======      =======        =======       =======
 
Net income per common share:
  Diluted                                   $.29         $.21           $.53          $.39
  Basic                                     $.31         $.22           $.56          $.41
 
Common shares:
 Diluted                                  13,384       13,082         13,391        13,077
 Basic                                    12,689       12,372         12,664        12,382
 
</TABLE>
                            (See Accompanying Notes)

                                       2
<PAGE>
 
                           OEC MEDICAL SYSTEMS, INC.
                          CONSOLIDATED BALANCE SHEETS
                      JUNE 30, 1998 AND DECEMBER 31, 1997
                   (In thousands, except per share amounts)
<TABLE>
<CAPTION>
 
                                    ASSETS
                                                                June 30, 1998   December 31, 1997
                                                                --------------  -----------------
                                                                 (unaudited)
<S>                                                                 <C>                 <C>
Current Assets:
 Cash and cash equivalents                                           $  9,994            $ 17,502
 Securities available for sale                                          5,535               2,843
 Accounts receivable, net of
    allowances of $1,283 and $1,114, respectively                      43,409              40,058
 Inventories, net                                                      36,202              28,376
 Prepaid expenses and other current assets                              2,140               2,988
 Income taxes receivable                                                  619               1,025
 Deferred income taxes                                                  8,236               7,304
                                                                     --------            --------
    Total current assets                                              106,135             100,096
 
Long-term receivables                                                     853                 998
Property and equipment, net                                            16,423              15,307
Cost in excess of net assets acquired, net of
 accumulated amortization of $9,613 and $9,155, respectively           10,435              10,893
Deferred income taxes                                                   1,561               2,643
Investment in unconsolidated affiliate                                  1,524                  --
Other assets                                                              978                 750
                                                                     --------            --------
    Total                                                            $137,909            $130,687
                                                                     ========            ========
 
</TABLE>
                     LIABILITIES AND STOCKHOLDERS' EQUITY
<TABLE>
<CAPTION>
 
Current Liabilities:
<S>                                                                 <C>                  <C>
 Accounts payable                                                    $ 11,846            $ 10,339
 Accrued salaries and benefits                                          4,544               5,172
 Accrued warranty and installation costs                                2,485               2,258
 Deferred income and customer deposits                                  4,677               5,075
 Accrued legal fees and litigation settlements                          4,917               4,697
 Accrued distributor commissions                                        3,013               3,725
 Other accrued liabilities                                              4,492               4,869
                                                                     --------            --------
    Total current liabilities                                          35,974              36,135
                                                                     --------            --------
 
 
Stockholders' Equity:
 Preferred stock, $.01 par value
    Authorized--2,000 shares, including 1,100 shares
    of convertible preferred stock, none outstanding                       --                  --
 Common stock, $.01 par value
    Authorized--30,000 shares
    Outstanding--13,722  and 13,474 shares, respectively                  137                 135
 Capital in excess of par value                                        85,554              82,317
 Retained earnings                                                     29,084              21,964
 Treasury stock, 1,095 and 970 shares at cost, respectively           (12,533)             (9,678)
 Foreign currency translation adjustment                                 (307)               (186)
                                                                     --------            --------
    Total stockholders' equity                                        101,935              94,552
                                                                     --------            --------
      Total                                                          $137,909            $130,687
                                                                     ========            ========
</TABLE>
                            (See Accompanying Notes)

                                       3
<PAGE>
 
                           OEC MEDICAL SYSTEMS, INC.
                     CONSOLIDATED STATEMENTS OF CASH FLOWS
                  FOR THE SIX MONTHS ENDED JUNE 30, 1998 AND
                                     1997
                                (In thousands)
                                  (unaudited)
<TABLE>
<CAPTION>
                                                                               1998                        1997
                                                                              ------                      ------
OPERATING ACTIVITIES:
<S>                                                                           <C>                         <C>
  Net income                                                                    $ 7,120                    $ 5,044
 Adjustments to reconcile net income
   to net cash provided by operating activities:
   Depreciation and amortization expense                                          1,815                      1,667
   Bad debt expense (recoveries)                                                     60                       (240)
   Deferred income tax expense                                                      150                        976
   Current tax benefit attributable to stock options exercised                    1,376                        486
   Changes in current assets and liabilities:
     Accounts receivable                                                         (3,411)                    (2,817)
     Inventories                                                                 (7,826)                    (1,996)
     Prepaid expenses and other current assets                                      848                       (765)
    Income taxes                                                                    406                       (298)
     Other assets                                                                  (228)                      (213)
     Accounts payable                                                             1,507                        364
     Accrued salaries and benefits                                                 (628)                    (1,056)
     Accrued warranty and installation costs                                        227                        209
     Deferred income and customer deposits                                         (398)                       186
     Accrued legal fees and litigation settlements                                  220                        118
     Accrued distributor commissions                                               (712)                        11
     Other accrued liabilities                                                     (377)                      (397)
                                                                                -------                    -------
   Net cash provided by operating activities                                        149                      1,279
                                                                                -------                    -------
 
INVESTING ACTIVITIES:
 Reduction (increase) in long-term receivables                                      145                       (634)
 Additions to property and equipment                                             (2,422)                    (1,744)
 Purchase of securities available for sale                                       (2,692)                        --
 Payment for the purchase of unconsolidated affiliate                            (1,575)                        --
 Cash acquired in connection with the acquisition of BMS                             --                        116
 Other                                                                             (121)                      (141)
                                                                                -------                    -------
   Net cash used by investing activities                                         (6,665)                    (2,403)
                                                                                -------                    -------
 
FINANCING ACTIVITIES:
 Common stock issued under benefit plans                                          1,863                      1,496
 Repurchase of warrants                                                              --                     (1,000)
 Purchases of treasury stock                                                     (2,855)                    (2,240)
                                                                                -------                    -------
 Net cash used by financing activities                                             (992)                    (1,744)
                                                                                -------                    -------
 
 Net decrease in cash and cash equivalents                                       (7,508)                    (2,868)
 Cash and cash equivalents at beginning of period                                17,502                     17,103
                                                                                -------                    -------
 Cash and cash equivalents at end of period                                     $ 9,994                    $14,235
                                                                                =======                    =======
 
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
 Cash paid during the period for interest                                       $    19                    $     5
 Cash paid during the period for income taxes                                   $ 1,874                    $ 1,503
 
SUPPLEMENTAL SCHEDULE OF NONCASH INVESTING AND FINANCING  ACTIVITIES:
 During the six months ended June 30, 1997, the Company increased its
  ownership in BMS from 19.8% to 100% as follows:
      Original 19.8% interest                                                                              $   190
      January 1, 1997 transactions:                                                                             
       Cash payment                                                                                            193
       Options granted                                                                                         274
       Loans converted to equity                                                                               615
Net liabilities acquired                                                                                       380
                                                                                                           -------
                                                              Cost in excess of net liabilities acquired   $ 1,652
                                                                                                           =======
</TABLE>

                           (See Accompanying Notes)
                           

                                       4
<PAGE>
 
                           OEC MEDICAL SYSTEMS, INC.
                  NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
                                  (UNAUDITED)
                            JUNE 30, 1998 AND 1997


1.  Interim information is unaudited but, in the opinion of Company management,
    all adjustments necessary for a fair presentation of interim results have
    been included.  The results for the three and six months ended June 30, 1998
    and 1997, are not necessarily indicative of the results to be expected for
    the entire year.  These consolidated financial statements and notes should
    be read in conjunction with the Company's consolidated financial statements
    for the year ended December 31, 1997, filed on Form 10-K on March 26, 1998.

2.  Inventories are stated at the lower of cost, utilizing the first-in/first-
    out  method, or market.  Inventories consist of the following:
<TABLE>
<CAPTION>
                                                              June 30,              December 31,
                                                               1998                     1997
                                                            ----------              ------------
                                                                     (In thousands)
<S>                                                         <C>                     <C>
       Purchased parts and completed subassemblies           $15,574                 $13,340
       Work-in-process                                         5,567                   4,301
       Finished goods                                            360                     456
       Demonstration equipment                                13,399                   8,985
       Service and repair parts                                5,978                   5,077
                                                             -------                 -------
       Total                                                  40,878                  32,159
       Less:  reserves for excess and obsolete inventory      (4,676)                 (3,783)
                                                             -------                 -------
       Net                                                   $36,202                 $28,376
                                                             =======                 =======
 
</TABLE>

3.  In June 1997, the Financial Accounting Standards Board (FASB) issued SFAS
    No. 130, "Reporting Comprehensive Income." SFAS No. 130 establishes
    standards for reporting and display of comprehensive income and its
    components (revenues, expenses, gains and losses) in a full set of general-
    purpose financial statements. This statement requires that an enterprise (a)
    classify items of other comprehensive income by their nature in a financial
    statement and (b) display the accumulated balance of other comprehensive
    income separately from retained earnings and additional paid-in capital in
    the equity section of a statement of financial position.

    Effective January 1, 1998, the Company adopted the provisions of SFAS No.
    130. Accordingly, the Company determined that the only transactions
    considered to be an additional component of comprehensive income is the
    cumulative effect of foreign currency translation adjustments. As of June
    30, 1998 and 1997, the cumulative effect of such transactions reduced
    stockholders' equity by approximately $307,000 and $376,000, respectively.
    The net impact to operations for the six months ended June 30, 1998 and 1997
    would reduce comprehensive income by approximately $121,000 and $141,000,
    respectively.
 
    In June 1997, the FASB issued SFAS No. 131, "Disclosures About Segments of
    an Enterprise and Related Information," which redefines how public business
    enterprises report information about operating segments in annual financial
    statements. The statement also establishes standards for related disclosures
    about products and services, geographical areas, and major customers. SFAS
    No. 131 is effective for annual financial statements for periods beginning
    after December 15, 1997. In the initial year of application, comparative
    information for earlier years is to be restated. The adoption of SFAS No.
    131 will likely not result in additional disclosures by the Company.

4.  On April 20, 1998, the Company's Board of Directors unanimously authorized
    the Company to repurchase 1,000,000 shares of the Company's common stock in
    the open market. The manner and timing of the repurchase will depend on
    market conditions and the Company's available cash reserves. As of June 30,
    1998, 125,000 shares had been repurchased under this plan.

                                       5
<PAGE>
 
                           OEC MEDICAL SYSTEMS, INC.
                ITEM 2: MANAGEMENT'S DISCUSSION AND ANALYSIS OF
                 FINANCIAL CONDITION AND RESULTS OF OPERATIONS
                                        

Except for historical information, this discussion contains forward-looking
statements that involve risks and uncertainties that could cause actual results
to differ materially from those projected.  Such risk and uncertainties include
those described in the "Factors That May Affect Future Operations" section on
page 8 of this Form 10-Q.

Results of Operations
---------------------

For the second quarter and six months ended June 30, 1998, OEC Medical Systems,
Inc. had net income of $3.9 million and $7.1 million, respectively, compared
with net income of $2.7 million and $5.0 million, respectively, for the same
periods in 1997. Operating income improved for the second quarter and six months
ended June 30, 1998, from $4.1 million and $7.3 million, respectively, in 1997
to $5.8 million and $10.6 million, respectively, in 1998.

The following table sets forth OEC's operating results as a percentage of net
sales:
<TABLE>
<CAPTION>
 
                                          Quarter Ended June 30,  Six Months Ended June 30,
                                             1998        1997        1998          1997
                                          ----------  ----------  ------------ ------------
    <S>                                   <C>         <C>         <C>          <C>
     Net sales:
         Product                                87.0        88.9          87.2         88.1
         Service                                13.0        11.1          12.8         11.9
                                               -----       -----         -----        -----
              Total net sales                  100.0       100.0         100.0        100.0
                                               -----       -----         -----        -----
 
     Cost of sales:
         Product                                48.2        50.9          48.4         51.1  
         Service                                 9.3         8.1           9.4          8.6
                                               -----       -----         -----        -----
              Total cost of sales               57.5        59.0          57.8         59.7
                                               -----       -----         -----        -----
         Gross margin                           42.5        41.0          42.2         40.3
                                               -----       -----         -----        -----
 
     Operating expenses:
     Research and development                    7.2         7.4           7.2          7.8
     Marketing and sales                        17.2        17.0          17.4         16.7
     Administrative, general and other           5.3         6.0           5.4          5.6
                                               -----       -----         -----        -----
              Total operating expenses          29.7        30.4          30.0         30.1
                                               -----       -----         -----        -----
 
     Operating income                           12.8        10.6          12.2         10.2
                                               -----       -----         -----        -----
 
     Net income                                  8.5         7.1           8.2          7.1
                                               =====       =====         =====        =====
</TABLE>
Sales and Markets
-----------------

Net sales for the quarter and six months ended June 30, 1998, were $45.5 million
and $87.1 million, respectively, compared with net sales of $38.9 million and
$71.2 million for the comparable periods of 1997.  This reflects a 17% and 22%
increase, respectively.  Product sales for the quarter and six months ended June
30, 1998 were $39.6 million and $76.0 million, respectively, compared with
product sales of $34.6 million and $62.7 million, respectively, for the same
periods last year.

The order rate in the second quarter was up 12% over last year, and for the six
months was up 18%, due in part, to particularly strong bookings generated by a
group buy promotional program that ended February 28, 1998.

Service revenue for the quarter and six months ended June 30, 1998 was $5.9
million and $11.2 million, respectively, compared with service revenue of $4.3
million for the same quarter last year and $8.5 million for the six month period
in 1997.  This is a 37% and 31% increase, respectively, reflecting the product
sales increases of the prior year.

                                       6
<PAGE>
 
International revenue was up 16% in the second quarter but down 9% for the six
month period, compared to prior year. The chief reasons for this shortfall are
the economic turmoil in Asia and the slower than expected progress in Latin
America.  International orders for the first half of 1998 were 8% higher than
the same period in 1997.  The Company has lowered its expectations of
international revenue for 1998.

Margin Analysis
---------------

OEC's gross margin was up to 42.5% of net sales for the second quarter and 42.2%
for the six months of 1998 compared to 41.0% and 40.3%, respectively, for the
same periods in 1997.  Despite continued pricing pressures, this margin
improvement was accomplished through continued efficiency gains in
manufacturing, increased overhead absorption resulting from higher production
volumes and as a result of sales of higher margin products like the Cardiac and
12 inch field-of-view C-arm products.

Service expenses increased by $1.1 million in the second quarter and $2.1
million for the six months, compared to the same periods in 1997.  This increase
is attributed to higher labor and material costs associated with the growth in
revenue.

Operating Expenses
------------------

Research and development costs increased by $0.4 million for the three-month
period and $0.8 million for the six months compared to the prior year.  This
reflects the Company's continuing investment in new product development and
enhancements such as the Series 9600 Cardiac System introduced in 1997 and the
Series and Compact 7700 introduced in 1998.

Marketing and sales expenses increased by $1.2 million or 18% for the quarter
and $3.3 million or 27% for the six months compared to the prior year, but were
up only 0.2% for the quarter and 0.7% for the six months as a percentage of net
sales.  This category was higher because of increased commission expense
associated with higher revenues, additional manpower in sales coverage and
application personnel worldwide, along with additional trade show participation.
Trade show activities expanded to accommodate a broader product line as well as
more countries.  In addition, OEC developed and implemented a comprehensive
cardiac training curriculum in the first quarter for its worldwide sales force.
This added to the increase, but it is expected to further enhance cardiac sales
going forward.

Administrative expenses as a percentage of sales were down for the second
quarter and first six months of 1998 compared to last year.

Income Taxes
------------

During the second quarter of 1998 and 1997, the Company recorded $2.1 million
and $1.6 million of tax expense, respectively.  The effective tax rate increased
slightly from 34.6% in the first six months of 1997 to 34.8% for the first six
months of 1998, and it is expected to remain around that level throughout 1998.

Liquidity and Capital Resources
-------------------------------

Cash provided by operations for the six months ended June 30,1998 and 1997 was
$0.1 million and $1.3 million, respectively. The primary operational cash usage
was for inventory increases to support increased production due to the broadened
product line and to provide additional demonstration units.

During the first six months of 1998, the Company used $6.7 million in investing
activities.  This cash usage was primarily made up of the minority interest
investment in Heartlab, Inc., a Rhode Island based medical imaging software
development company with a focus on cardiology, for purchase of $2.7 million of
securities, and for additions to property and equipment.  The building additions
to the Salt Lake City facility were completed in the second quarter and were
fully occupied without any disruptions of productivity.

On April 20, the board of directors of OEC authorized a one million share
repurchase program to commence immediately.  There is no time limitation on its
completion.  OEC believes that it has sufficient liquidity and 

                                       7
<PAGE>
 
anticipated cash flow to meet its obligations and support the share repurchase
program in 1998. In addition, OEC continues to carry an unused $10 million line
of credit.

Factors That May Affect Future Results
--------------------------------------

Except for historical information, this discussion contains forward-looking
statements that involve risks and uncertainties that could cause actual results
to differ materially from those projected.  Such risks and uncertainties
include: product demand and market acceptance; the effect of general economic
conditions and foreign currency fluctuations; the impact of competitive products
and pricing; new product development and commercialization; the effect of the
continuing shift in growth from domestic to international healthcare customers;
the impact of managed care initiatives in the United States; and the ability to
increase operating margins on higher sales.

OEC's future operating results are dependent on its ability to develop,
manufacture and market innovative products that meet customers' needs.  The
process of developing new high technology medical products is complex and
uncertain and requires innovative designs that anticipate customer needs,
technological trends and healthcare shifts.  There can be no assurance that the
Company will be able to develop and market new products on a cost-effective and
timely basis, that such products will compete favorably with products developed
by others or that existing technology will not be superseded by new discoveries
or breakthroughs.

Because of the substantial length of time and expense associated with bringing
new products through development and regulatory approval to the marketplace, the
medical device industry places considerable importance on obtaining patent,
trademark, copyright and trade secret protection for new technologies, products
and processes.  The loss of protection could have a material adverse effect on
the Company's business.

OEC depends on some significant and single-source vendors for certain important
component parts for certain products.  While the Company believes any of these
single-source items could be replaced over time, abrupt disruption in the supply
of a part for a product could have a material adverse effect on the Company's
production and on its financial condition and results of operations in cases
where the existing inventory of the components is not adequate to meet the
Company's demand for the component during such disruption.

The testing, marketing and sale of human healthcare products entails an inherent
risk of product liability, and there can be no assurance that product liability
claims will not be asserted against OEC.  Although OEC has product liability
insurance coverage, there can be no assurance that such coverage will provide
adequate coverage against all potential claims.

As a manufacturer of medical devices, OEC is subject to extensive and rigorous
governmental regulation, principally by the FDA and corresponding state and
foreign agencies. Failure to comply with FDA regulations could result in
sanctions being imposed, including restrictions on the marketing of or recall of
the affected products.  The FDA and other agencies have periodically inspected
OEC's facilities and manufacturing processes, but remain subject to further
inspections from time to time.  OEC continues to devote substantial human and
financial resources to regulatory compliance and believes that it remains in
substantial compliance with all applicable federal and state regulations.
Nevertheless, there can be no assurance that the FDA or a state agency will
agree with OEC's positions, or that its GMP or ISO compliance will not be
challenged at some subsequent point in time.

A portion of the Company's research and development activities, some of its
single-source vendors, its corporate headquarters and other critical business
operations are located near a major earthquake fault.  The ultimate impact on
the Company, significant suppliers and the general infrastructure is unknown,
but operating results could be materially affected in the event of a major
earthquake.

Although OEC believes that it has the product offerings and resources needed for
continuing success, future revenue and margin trends cannot be reliably
predicted and may cause the Company to adjust its operations.  Factors external
to the Company can result in volatility of the Company's common stock price.

                                       8
<PAGE>
 
Foreign Currency Rate Exposure
------------------------------

The Company has operating subsidiaries located in Europe and utilizes forward
exchange contracts with durations generally less than six months to hedge
against the effect of exchange rate fluctuations of European income.   The
Company also has other customers located throughout the world; however, these
customers' invoices are denominated in U.S. dollars.  As a result, the Company
has not incurred material gains or losses resulting from foreign currency
fluctuations.  The Company's forward exchange contracts are not material.

Interest Rate Risk Exposure
---------------------------

The Company has purchased certain debt obligations of the U.S. government and
various corporations with maturities generally less than one year.  As of June
30, 1998, such investments totaled approximately $5.5 million and the difference
between amortized cost and fair market value is immaterial.  Interest rate risk
and default risk underlying these securities is not considered to be
significant.

Other Exposures
---------------

The Company has not entered into any speculative derivatives and does not
foresee utilizing such instruments in the future.  The Company does not utilize
commodities in the normal course of its manufacturing process.  Accordingly, the
Company does not believe it has any significant commodity risks or exposures.

Year 2000 Compliance
--------------------

The Company has reviewed its primary financial and other business information
systems and it believes that these systems will be able to manage and manipulate
all material data involving the transition from 1999 to 2000 without functional
or data abnormality and without inaccurate results related to such data.  Two
tertiary computer systems are in the process of being upgraded to Year 2000
compliance and reviews are underway with all suppliers, especially sole-source
vendors, to ensure compliance. The Company has reviewed the software associated
with the operation of its products to ensure Year 2000 compliance and has
determined that such software is capable of meeting the compliance standards.
While the Company believes the issues associated with Year 2000 compliance have
been or are being addressed, there remains the risk that suppliers may encounter
disruptions due to Year 2000 compliance or the costs associated with
implementing computer system changes would have an adverse effect on the
Company's results of operations and financial condition.  There is also risk
that Year 2000 compliance may have an effect on the purchase patterns of
customers that would adversely affect demand for the Company's products for a
period of time.


PART II.  Other information

ITEM 1.  Legal proceedings

There are no significant changes in legal proceedings from the previous stated
position in the Company's Annual Report for 1997 or Form 10K filed with the
Securities & Exchange Commission on March 26, 1998.

                                       9
<PAGE>
 
ITEM 6.  Exhibits

(a)  The following exhibit (numbered in accordance with Item 601 of SEC
     Regulations S-K) is filed as part of this report:

    Exhibit
     Number     Description
    --------             


     3.1        Certificate of Incorporation, as amended. Incorporated by
                reference to the OEC Medical Systems, Inc. Form 10-K, filed
                March 30, 1994.

     3.2        By-Laws, as amended May 15, 1997. Incorporated by reference to
                the OEC Medical Systems, Inc. Form 10-Q, filed August 8, 1997.

     4          Rights Agreement, dated as of June 20, 1988, between Diasonics,
                Inc. and Bank of America NT&SA. Incorporated by reference to
                Exhibit 4.3 of the Diasonics, Inc. Form 8-K, filed August 1,
                1988

    10.1        Diasonics, Inc. 1979 Stock Option Plan, amended and restated as
                of June 1, 1982. Incorporated by reference to Exhibit 10.6 of
                the Diasonics, Inc. Registration Statement on Form S-8, filed
                May 2, 1983.

    10.4        Diasonics, Inc. 1990 Stock Option/Stock Purchase Plan.
                Incorporated by reference to Exhibit 10.79 of the Diasonics,
                Inc. Form S-8, filed on May 1, 1991.

    10.5        Warrant for the Purchase of Common Shares issued to PaineWebber
                R&D Partners II, L.P., as amended. Incorporated by reference to
                the OEC Medical Systems, Inc. Form 10-K, filed on March 30,
                1994.

    10.14       Form of Option Agreement used in connection with options having
                service-vesting provisions. Incorporated by reference to the OEC
                Medical Systems, Inc. Form S-8, filed June 12, 1998.

    10.15       Form of Option Agreement used in connection with options having
                milestone provisions. Incorporated by reference to the OEC
                Medical Systems, Inc. Form S-8, filed June 12, 1998.

    10.16       Form of Option Agreement used in connection with automatic
                option grant program for non-employee directors. Incorporated by
                reference to the OEC Medical Systems, Inc. Form S-8, filed June
                12, 1998.

    10.20       Form of Warrant Agreement used in connection with grant to
                independent contractors for the purchase of common shares.
                Incorporated by reference to the OEC Medical Systems, Inc. Form
                10-K, filed March 27, 1997.

    10.21       Agreement dated December 17, 1996, to acquire full ownership of
                Barwig Medizinische Systeme GmbH (BMS). Incorporated by
                reference to the OEC Medical Systems, Inc. Form 10-K, filed
                March 27, 1997.

    10.22       Agreement dated January 10, 1997 to repurchase warrants for the
                purchase of common shares issued to PaineWebber R&D Partners II,
                L.P. Incorporated by reference to the OEC Medical Systems, Inc.
                Form 10-Q, filed May 13, 1997.

                                       10
<PAGE>
 
    10.23  Offer of Employment between Joseph W. Pepper and OEC Medical Systems,
           Inc. dated April 21, 1997. Incorporated by reference to the OEC
           Medical Systems, Inc. Form 10-Q, filed August 8, 1997.

    10.24  OEC Medical Systems, Inc. 1993 Employee Incentive Stock Acquisition
           Plan, as amended and re-stated March 31, 1998. Incorporated by
           reference to the OEC Medical Systems, Inc. Form S-8, filed June 12,
           1998.

    10.25  OEC Medical Systems, Inc. 1998 Stock Option Plan. Incorporated by
           reference to the OEC Medical Systems, Inc. Form S-8, filed June 12,
           1998.

    10.26  Form of Option Agreement used in connection with the granting of
           incentive stock options. Incorporated by reference to the OEC Medical
           Systems, Inc. Form S-8, filed June 12, 1998.

    11     Statement of Computation of Per Share Earnings.

    21     List of Subsidiaries.  Incorporated by reference to the OEC Medical
           Systems, Inc. Form 10-Q, filed May 13, 1997.

    27     Financial Data Schedule (FDS) for Edgar Filing.

     (b)   Reports on Form 8-K:
           Not Applicable

                                       11
<PAGE>
 
                                   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.



OEC MEDICAL SYSTEMS, INC.
(Registrant)



By:       /s/ Randy W. Zundel
          --------------------------

          Randy W. Zundel
          Chief Financial Officer
          (Principal Accounting Officer)


Date:  August 7, 1998

                                       12