<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           September 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 October 20, 1998, there were 12,724,551 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 & NINE MONTHS ENDED SEPTEMBER 30, 1998 AND 1997
                   (In thousands, except per share amounts)

<TABLE>
<CAPTION>
                                       Quarter Ended September 30,    Nine Months Ended September 30,
                                           1998           1997             1998             1997
                                       ---------------------------    -------------------------------
<S>                                    <C>                 <C>        <C>                    <C>
Net sales
  Product                                   $42,005        $34,519          $117,966         $ 97,209
  Service                                     5,875          4,440            17,056           12,944
                                            -------        -------          --------         --------
     Total net sales                         47,880         38,959           135,022          110,153
                                            -------        -------          --------         --------
 
Cost of sales
  Product                                    23,336         19,542            65,516           55,959
  Service                                     4,172          3,288            12,383            9,405
                                            -------        -------          --------         --------
     Total cost of sales                     27,508         22,830            77,899           65,364
                                            -------        -------          --------         --------
     Gross margin                            20,372         16,129            57,123           44,789
                                            -------        -------          --------         --------
 
Operating expenses
  Research and development                    3,305          2,776             9,589            8,295
  Marketing and sales                         7,916          6,177            23,079           18,081
  Administrative, general and other           2,425          2,125             7,148            6,103
                                            -------        -------          --------         --------
     Total operating expenses                13,646         11,078            39,816           32,479
                                            -------        -------          --------         --------
 
Operating income                              6,726          5,051            17,307           12,310
 
Interest income                                 264            220               754              677
Interest expense                                (68)            (1)             (213)              (6)
                                            -------        -------          --------         --------
 
Income before income taxes                    6,922          5,270            17,848           12,981
 
Income tax expense                            2,606          1,825             6,412            4,492
                                            -------        -------          --------         --------
Net income                                  $ 4,316        $ 3,445          $ 11,436         $  8,489
                                            =======        =======          ========         ========
 
Net income per common share:
  Diluted                                     $0.32          $0.26             $0.85            $0.65
  Basic                                        0.34           0.28              0.90             0.69
 
Common shares:
  Diluted                                    13,354         13,132            13,378           13,096
  Basic                                      12,709         12,393            12,679           12,386
</TABLE>


                           (See Accompanying Notes)

                                                      
                                                      
                                                                               2


<PAGE>
 
                           OEC MEDICAL SYSTEMS, INC.
                          CONSOLIDATED BALANCE SHEETS
                   SEPTEMBER 30, 1998 AND DECEMBER 31, 1997
                                (In thousands)

<TABLE>
<CAPTION>
                                                    ASSETS
                                                                September 30, 1998   December 31, 1997
                                                                -------------------  -----------------
                                                                    (unaudited)
<S>                                                             <C>                  <C>
Current Assets:
 Cash and cash equivalents                                                $ 16,214            $ 17,502
 Securities available for sale                                               6,726               2,843
 Accounts receivable, net of
    allowances of $1,255 and $1,114, respectively                           39,668              40,058
 Inventories, net                                                           41,292              28,376
 Prepaid expenses and other current assets                                     849               2,988
 Income taxes receivable                                                        70               1,025
 Deferred income taxes                                                       8,173               7,304
                                                                          --------            --------
    Total current assets                                                   112,992             100,096
 
Long-term receivables                                                        1,119                 998
Property and equipment, net                                                 17,179              15,307
Cost in excess of net assets acquired, net of
 accumulated amortization of $9,884 and $9,155, respectively                10,164              10,893
Deferred income taxes                                                        1,341               2,643
Investment in unconsolidated affiliate                                       1,473                  --
Other assets                                                                   876                 750
                                                                          --------            --------
    Total                                                                 $145,144            $130,687
                                                                          ========            ========

<CAPTION>
                                  LIABILITIES AND STOCKHOLDERS' EQUITY


Current Liabilities:
<S>                                                                       <C>                 <C>     
 Accounts payable                                                         $ 12,332            $ 10,339
 Accrued salaries and benefits                                               5,937               5,172   
 Accrued warranty and installation costs                                     2,644               2,258
 Deferred income and customer deposits                                       4,707               5,075
 Accrued legal fees and litigation settlements                               5,077               4,697
 Accrued distributor commissions                                             2,888               3,725
 Other accrued liabilities                                                   4,452               4,869 
                                                                          --------            --------
    Total current liabilities                                               38,037              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
    Issued--13,895 and 13,474 shares, respectively                             139                 135 
 Capital in excess of par value                                             88,051              82,317
 Retained earnings                                                          33,400              21,964
 Treasury stock, 1,171 and 970 shares at cost, respectively                (14,258)             (9,678)
 Foreign currency translation adjustment                                      (225)               (186)
                                                                          --------            --------
    Total stockholders' equity                                             107,107              94,552
                                                                          --------            -------- 
      Total                                                               $145,144            $130,687
                                                                          ========            ========
</TABLE>


                           (See Accompanying Notes)

                                                                               3
<PAGE>
 
                           OEC MEDICAL SYSTEMS, INC.
                     CONSOLIDATED STATEMENTS OF CASH FLOWS
             FOR THE NINE MONTHS ENDED SEPTEMBER 30, 1998 AND 1997
                                (In thousands)
                                  (unaudited)

<TABLE>
<CAPTION>
                                                                           1998       1997
                                                                         ---------  --------
<S>                                                                      <C>        <C>
OPERATING ACTIVITIES:
    Net income                                                           $ 11,436   $ 8,489
    Adjustments to reconcile net income
         to net cash provided by operating activities:
         Depreciation and amortization                                      3,600     2,557
         Deferred income tax expense                                          433     1,454
         Current tax benefit attributable to stock options exercised        2,281       546
         Changes in current assets and liabilities, net of effects of
            purchase of subsidiary:
              Accounts and notes receivable, net                              390    (5,898)
              Inventories                                                 (12,916)   (3,623)
              Prepaid expenses and other current assets                     2,139    (1,186)
              Other assets, net                                               955      (213)
              Accounts payable                                               (126)    1,256
              Accrued salaries and benefits                                 1,993      (182)
              Accrued warranty and installation costs                         765       496
              Deferred income and customer deposits                           386      (117)
              Income taxes payable                                           (368)     (216)
              Accrued legal fees and litigation settlements                   380       187
              Accrued distributor commissions                                (837)       23
              Other accrued liabilities                                      (417)     (119)
                                                                         --------   -------
         Net cash provided by operating activities                         10,094     3,454
                                                                         --------   -------
 
INVESTING ACTIVITIES:
    Increase in long-term receivables                                        (121)     (553)
    Additions to property and equipment                                    (4,641)   (3,448)
    Purchase of securities available for sale                              (3,883)       --
    Payment for the purchase of unconsolidated affiliate                   (1,575)       --
    Net cash acquired upon purchase of subsidiary                              --       116
    Other                                                                     (39)      (87)
                                                                         --------   -------
         Net cash used by investing activities                            (10,259)   (3,972)
                                                                         --------   -------
 
FINANCING ACTIVITIES:
    Common stock issued under benefit plans                                 3,457     2,040
    Repurchase of warrants                                                     --    (1,000)
    Purchases of treasury stock                                            (4,580)   (2,435)
                                                                         --------   -------
         Net cash used by financing activities                             (1,123)   (1,395)
                                                                         --------   -------
 
    Net decrease in cash and cash equivalents                              (1,288)   (1,913)
    Cash and cash equivalents at beginning of period                       17,502    17,103
                                                                         --------   -------
 
    Cash and cash equivalents at end of period                           $ 16,214   $15,190
                                                                         ========   =======
 
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
    Cash paid during the period for interest                             $     25   $     6
    Cash paid during the period for income taxes                         $  2,741   $ 2,708
</TABLE> 

<TABLE> 
SUPPLEMENTAL SCHEDULE OF NONCASH INVESTING AND FINANCING  ACTIVITIES:
 During the nine months ended September 30, 1997, the Company increased its
 ownership in BMS from 19.8% to 100% as follows:
<S>                                                                                  <C>   
                  Original 19.8% interest                                            $  190
                  January 1, 1997 transactions:                                             
                    Cash payment                                                        193
                    Options granted                                                     274
                    Loans converted to equity                                           615
                                                                                     ------
                      Total investment                                                1,272
                    Net Liabilities acquired                                            380
                                                                                     ------ 
                  Total purchase price in excess of net liabilities acquired         $1,652
                                                                                     ====== 
                           (See Accompanying Notes)
</TABLE> 

                                                                               4
<PAGE>
 
                           OEC MEDICAL SYSTEMS, INC.
                  NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
                                  (UNAUDITED)
                          SEPTEMBER 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 nine months ended September
    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>
                                                                 September 30,            December 31,       
                                                                     1998                     1997           
                                                                     ----                     ----           
                                                                              (In thousands)             
          <S>                                                    <C>                      <C>                
          Purchased parts and completed subassemblies                $20,070                  $13,340        
          Work-in-process                                              5,456                    4,301        
          Finished goods                                               2,205                      456        
          Demonstration equipment                                     12,315                    8,985        
          Service and repair parts                                     6,048                    5,077        
                                                                     -------                  -------        
          Total                                                       46,094                   32,159        
          Less:  reserves for excess and obsolete inventory           (4,802)                  (3,783)       
                                                                     -------                  -------        
          Net                                                        $41,292                  $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 capital in excess of par value
    in the equity section of a balance sheet.

    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
    September 30, 1998 and 1997, the cumulative effect of such transactions
    reduced stockholders' equity by approximately $225,000 and $322,000,
    respectively. The net impact to operations for the nine months ended
    September 30, 1998 and 1997 would reduce comprehensive income by
    approximately $39,000 and $87,000, 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 September
    30, 1998, 200,400 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 third quarter and nine months ended September 30, 1998, OEC Medical
Systems, Inc. had net income of $4.3 million and $11.4 million, respectively,
compared with net income of $3.4 million and $8.5 million, respectively, for the
same periods in 1997. Operating income improved for the third quarter and nine
months ended September 30, 1998, from $5.1 million and $12.3 million,
respectively, in 1997 to $6.7 million and $17.3 million, respectively, in 1998.

The following table sets forth OEC's operating results as a percentage of net
sales:

<TABLE>
<CAPTION>
                                                  Quarter Ended September 30,        Nine months Ended September 30,
                                                        1998        1997                     1998        1997
                                                        ----------------                     ----------------
     <S>                                          <C>              <C>               <C>                <C>
     Net sales:
         Product                                        87.7        88.6                     87.4        88.2        
         Service                                        12.3        11.4                     12.6        11.8        
                                                       -----       -----                    -----       -----        
              Total net sales                          100.0       100.0                    100.0       100.0        
                                                       -----       -----                    -----       -----        
                                                                                                                     
     Cost of sales:                                                                                                  
         Product                                        48.8        50.2                     48.5        50.8        
         Service                                         8.7         8.4                      9.2         8.5        
                                                       -----       -----                    -----       -----        
              Total cost of sales                       57.5        58.6                     57.7        59.3        
                                                       -----       -----                    -----       -----        
         Gross margin                                   42.5        41.4                     42.3        40.7        
                                                       -----       -----                    -----       -----         
 
     Operating expenses:
         Research and development                        6.9         7.1                      7.1         7.5
         Marketing and sales                            16.5        15.9                     17.1        16.4
         Administrative, general and other               5.1         5.4                      5.3         5.6
                                                       -----       -----                    -----       -----
              Total operating expenses                  28.5        28.4                     29.5        29.5
                                                       -----       -----                    -----       ----- 
 
     Operating income                                   14.0        13.0                     12.8        11.2
                                                       -----       -----                    -----       ----- 

     Net income                                          9.0         8.8                      8.5         7.7
                                                       =====       =====                    =====       ===== 
</TABLE>

Sales and Markets
-----------------

Net sales for the quarter and nine months ended September 30, 1998, were $47.9
million and $135.0 million, respectively, compared with net sales of $39.0
million and $110.2 million for the comparable periods of 1997. This reflects a
23% increase for both periods. Product sales for the quarter and nine months
ended September 30, 1998 were $42.0 million and $118.0 million, respectively,
compared with product sales of $34.6 million and $97.2 million, respectively,
for the same periods last year.

The order rate in the third quarter was up 26% over last year, and for the nine
months was up 21%, due in part, to increased demand for the higher-end mobile C-
arms and strong urology system orders. Service revenue for the quarter and nine
months ended September 30, 1998 was $5.9 million and $17.1 million,
respectively, compared with service revenue of $4.4 million for the same quarter
last year and $12.9 million for the nine month period in 1997. This is a 32%
increase for both periods, reflecting the product sales increases of the prior
year.

                                                                               6
<PAGE>
 
International revenue was up 13% in the third quarter and 2% for the nine month
period, compared to the prior year. International orders for the first nine
months of 1998 were 14% higher than the same period in 1997. The Company has
lowered its expectations of international revenue for 1998, due to the decline
of business in Asia.

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

OEC's gross margin was up to 42.5% of net sales for the third quarter and 42.3%
for the nine months of 1998 compared to 41.4% and 40.7%, respectively, for the
same periods in 1997.  Despite continued pricing pressures, this margin
improvement was accomplished through lower warranty costs, 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 $0.9 million in the third quarter and $3.0 million
for the nine 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 $0.5 million for the three-month
period and $1.3 million for the nine months compared to the prior year. The
Company expects to continue to invest in new product development and
enhancements at a level of approximately 7% of revenue.

Marketing and sales expenses increased by $1.7 million or 28% for the quarter
and $5.0 million or 28% for the nine months compared to the prior year, but were
up only 0.7% for the nine months as a percentage of net sales.  This category
was higher because of increased commission and sales incentive expenses
associated with exceeding sales goals, additional manpower in sales coverage and
application personnel worldwide, along with expanded workshop support expenses.
The Company's support of physicians training workshops reinforces the use of OEC
equipment for new applications and generates leads for future business.

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

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

During the third quarter of 1998 and 1997, the Company recorded $2.6 million and
$1.8 million of tax expense, respectively.  The effective tax rate increased
from 34.6% in the first nine months of 1997 to 35.9% in the first nine months of
1998 as the Company recalculated its deferred tax assets and saw the elimination
of research and development tax credits in the third quarter which were
subsequently reinstated in the fourth quarter.

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

Cash provided by operations for the nine months ended September 30,1998 and 1997
was $10.1 million and $3.5 million, respectively. The cash increase from net
income was primarily offset by inventory increases.  The additional inventory is
to support expanded production and to provide additional demonstration units.

During the first nine months of 1998, the Company used $10.3 million in
investing activities.  This cash usage was primarily for purchase of $3.9
million of securities available for sale; the purchase of a minority interest
investment in Heartlab, Inc., a Rhode Island based medical imaging software
development company with a focus on cardiology; 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
in 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.  During 1998, the Company has repurchased approximately 200,000
shares for $4.6 million. OEC believes that it has sufficient liquidity and
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.

                                                                               7
<PAGE>
 
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.

Foreign Currency Rate Exposure
------------------------------

The Company has operating subsidiaries located in Europe and utilizes forward
exchange contracts with durations generally less than nine months to hedge
against the effect of exchange rate fluctuations of European income. The

                                                                               8
<PAGE>
 
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
September 30, 1998, such investments totaled approximately $6.7 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 purchasing 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.

      10.23  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.
              
<PAGE>
 
      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
<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:  November 3, 1998