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

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D. C. 20549

                                    FORM 10-K

                  ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d)
                     OF THE SECURITIES EXCHANGE ACT OF 1934.

                   FOR THE FISCAL YEAR ENDED DECEMBER 31, 1997
                          COMMISSION FILE NUMBER 1-9983


                            OEC MEDICAL SYSTEMS, INC.
             (Exact name of registrant as specified in its charter)


           DELAWARE                                    94-2538512
(State or other jurisdiction of          (I.R.S. Employer Identification Number)
incorporation or organization)

        384 WRIGHT BROTHERS DRIVE                        84116
          SALT LAKE CITY, UTAH                          Zip Code
(Address of principal executive offices)


                                 (801) 328-9300
                         (Registrant's telephone number)

           Securities registered pursuant to Section 12(b) of the Act:
                  Listed on the New York Stock Exchange (NYSE)

                          Common Stock, $.01 par value

        Securities registered pursuant to Section 12(g) of the Act: None

     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 short period that the Registrant
was required such reports and (2) has been subject to such filing requirements
for the past 90 days.  Yes [X]  No [ ]

     Indicate by check mark if disclosure of delinquent filers pursuant to Item
405 of Regulation S-K is not contained herein, and will not be contained, to the
best of registrant's knowledge, in definitive proxy or information statements
incorporated by reference in Part III of this Form 10-K or any amendment to this
Form 10-K. [ ]

     The aggregate market value of Common Stock held by non-affiliates (based on
the closing sales price on the New York Stock Exchange) on March 1, 1998 was
approximately $279,175,810.

     As of March 1, 1998, there were 12,725,963 shares of Common Stock with $.01
par value outstanding.

Documents Incorporated by Reference:                              Form 10-K Part

(1) Portions of Definitive Proxy Statement to be mailed to stockholders in
    connection with the Registrant's 1998 Annual Meeting of Stockholders  I, III
(2) Portions of the Annual Report to Shareholders for fiscal year ended
    December 31, 1997                                                         II

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



<PAGE>   2

                            OEC MEDICAL SYSTEMS, INC.

                          1997 FORM 10-K ANNUAL REPORT

                                TABLE OF CONTENTS

<TABLE>

<S>          <C>                                                                                            <C>
PART I
Item 1.      Business                                                                                       2
Item 2.      Properties                                                                                     5
Item 3.      Legal Proceedings                                                                              5
Item 4.      Submission of Matters to a Vote of Security Holders                                            6
             Executive Officers of the Registrant                                                           6

PART II
Item 5.      Market for Registrant's Common Equity and Related Stockholder Matters                          7
Item 6.      Selected Financial Data                                                                        7
Item 7.      Management's Discussion and Analysis of Financial Condition and Results of Operations          8
Item 7A.     Quantitative and Qualitative Disclosures about Market Risk                                     N/A
Item 8.      Financial Statements and Supplemental Data                                                     8
Item 9.      Changes In and Disagreements with Accountants on Accounting and Financial Disclosure           8

PART III
Item 10.     Directors and Executive Officers of Registrant                                                 8
Item 11.     Executive Compensation                                                                         8
Item 12.     Security Ownership of Certain Beneficial Owners and Management                                 8
Item 13.     Certain Relationships and Related Transactions                                                 8

PART IV
Item 14.     Exhibits, Financial Statement Schedules and Reports on Form 8-K                                9
</TABLE>



                                       2
<PAGE>   3

                            OEC MEDICAL SYSTEMS, INC.

                          1997 FORM 10-K ANNUAL REPORT

                                     PART I

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:
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,
and the impact of managed care initiatives in the United States and the ability
to increase operating margins on higher sales as further described in the "Risk
Factors" section on page 4 of this Form 10-K.


ITEM 1.      BUSINESS

     General. OEC develops, manufactures, markets, and services computer-based
X-ray fluoroscopic imaging systems for use in hospitals, outpatient clinics,
physicians' offices and surgery-centers for minimally invasive intraoperative
and interventional procedures.

     OEC was originally established in Indiana in 1942. In response to surgeons'
need for improved methods to monitor and guide the implantation of various
internal fixation devices, OEC entered the medical X-ray imaging market in 1972.
Diasonics, Inc. (Diasonics) in October 1983 acquired OEC as a separate operating
subsidiary. The Company was merged into Diasonics in September of 1993. As part
of the restructuring, the other operating businesses of Diasonics were spun off
to shareholders and the Diasonics name was changed to OEC Medical Systems, Inc.

     Today, OEC is recognized as the pioneer and continuing United States market
leader of intraoperative X-ray imaging systems. These systems combine
radiographic and fluoroscopic imaging with digital image processing
capabilities. X-rays are passed through the body and either recorded on
radiographic film or passed through an image intensifier system and displayed as
a real-time fluoroscopic image on a video monitor. Digital image processing of
the fluoroscopic image improves the image quality, contributes to lowering X-ray
dosage and results in reduced costs for a number of applications.

     OEC seeks to provide cost-effective imaging systems directed towards
medical specialties in which minimally invasive techniques are replacing
expensive and more traumatic open surgical procedures. High quality digital
fluoroscopy has become mandatory in many of today's modern operating room.
Minimally invasive techniques are expanding into many areas of surgery
(vascular, neurological, orthopedic, urological, cardiac and general surgery).
OEC's products are designed to meet the needs of these new procedures.

     Technical leadership, strong customer relationships, a cost-effective
product line and full-line service capabilities have earned OEC the United
States market leadership position in the intraoperative X-ray imaging markets
which it addresses.

     OEC believes its international markets represent a significant growth
opportunity and continues to expand its network of international distributors.
Building on its leadership position in the U.S., OEC's focus is to become the
worldwide leader for intraoperative and interventional fluoroscopic imaging.
With this focus in mind, OEC has been investing in the future through research
and development. The introductions of the Series 9600 Mobile Digital Imaging
System in 1994, the Uroview 2600 urology table, the Mini 6600 and the Compact
7600 all introduced in 1995, the 9600 Mobile Cardiac Cath Lab and the dual mode
Mini 6600 introduced in 1997, are the results of these investments.

     OEC's expanding presence in international markets is another example of the
Company's investment in the future. OEC has strengthened its wholly owned
subsidiaries in France, Germany, Italy and Switzerland with additional personnel
and training, and has designed its new products to be more appealing and
acceptable to international customers. OEC also strengthened its international
network in new markets by establishing new distributors and strengthening
existing distributors throughout the world. OEC intends to continue these
activities during 1998.



                                       3
<PAGE>   4

     OEC's Products. The products produced by OEC consist of mobile X-ray
imaging systems as well as fixed-room urological X-ray imaging systems.

     C-arm Products. In March 1994, OEC introduced the Series 9600 Mobile
Digital Imaging System. This mobile imaging device can be wheeled from operating
room to operating room to provide high quality, real-time fluoroscopic imaging
for a wide variety of surgical and interventional procedures that require X-ray
guidance.

     The modular architecture of the system allows the Series 9600 to be
tailored to meet the needs of the surgeon. For example, the Series 9600 can be
equipped with an expanded surgical package for general surgery and orthopedics.
When equipped with a vascular special procedures module, it can perform complex
subtraction angiography in the operating room, emergency room, or in radiology.
The most advanced version of the Series 9600 can perform many of the tasks of a
sophisticated, fixed-room digital X-ray system costing several times more than
the Series 9600. Prices of the Series 9600 Mobile Digital Imaging System range
from $100,000 to $230,000.

     The Series 9600 Mobile Cardiac Cath Lab was introduced in 1997. This
proprietary version of the Series 9600 offers the same imaging capability found
in many fixed room cath labs with all the convenience and cost effectiveness of
a mobile imaging system. This system is the basis for the Company's strategic
alliances with device manufacturers associated with minimally invasive cardiac
surgeries. Surgeons use the Series 9600 Cardiac system to confirm patency
following minimally invasive cardiac procedures. Prices for the Series 9600
Mobile Cardiac Cath Lab range from $190,000 to $250,000.

     In response to changes brought on by managed healthcare, OEC introduced
three lower cost digital mobile X-ray machines - the Compact 7600, Series 7600
and the Mini 6600. These smaller, lower cost machines are specifically designed
to address the imaging requirements of outpatient surgery centers as well as
other satellite surgery delivery sites. The move towards less invasive surgeries
with accompanying shorter recovery times is driving the need for easy to
operate, cost effective fluoroscopic guidance systems in all locations of the
healthcare delivery network.

     The Compact 7600 Digital Mobile C-Arm is a cost effective, simple to
operate, full-body imaging system that can be utilized for most routine, less
complicated procedures. Its compact, one-piece design (no separate monitor cart)
allows for ease of transport, quick positioning and minimal storage
requirements. Prices of the Compact 7600 range from $75,000 to $95,000. The
Series 7600 has the same functionality as that of the Compact, but it has a
separate workstation. The addition of the workstation allows the Series 7600 to
be upgraded in features and capabilities in order to perform more complicated
procedures. The price range for the Series 7600 is $80,000 to $100,000.

     The dual mode version of the Mini 6600 Digital Mobile C-Arm was introduced
in 1997. Like its forerunner the Mini 6600, it is a smaller digital fluoroscopic
imaging system that has been specifically designed to provide high quality
images of upper and lower extremities. Areas of use include hospital operating
rooms and emergency rooms, outpatient surgery centers, specialty physician
offices and veterinary clinics. Prices of the Mini 6600 range from $45,000 to
$70,000.

     During 1997, 1996 and 1995, the OEC C-arm business represented 80%, 77% and
82% of total product sales, respectively.

     UroView 2600 Digital Imaging System. Urology is another surgical specialty
requiring intraoperative imaging that has largely moved away from the use of
static X-ray films to monitor and guide procedural progress. Diagnostic and
interventional urological procedures are often performed in a separate area of
the operating room environment known as the Cysto Department. Until the late
80s, these specialized rooms were equipped with a fixed (bolted down)
urological-specific patient positioning table (motorized in movement) that also
had static X-ray filming capability built in. These films, once exposed, would
need to be taken to a darkroom in radiology to be developed prior to being
brought back to the Cysto Department for evaluation by the urologist. This
resulted in long procedural delays. Additionally, real-time events could not be
recorded since radiographic film produces only a static image. Eventually,
real-time fluoroscopic imaging capabilities were added to these systems. In
1987, OEC introduced the Uroview, which was the industry's first urological
table with fully integrated digital fluoroscopy. This resulted in significant
image improvement, pulsed fluoro for lower dose than prior systems, and



                                       4
<PAGE>   5

reduced costs compared to existing urological imaging systems. Prices for the
Uroview system presently range from $210,000 to $230,000.

     During 1997, 1996 and 1995, the OEC urology business represented 20%, 23%
and 18% of total product sales, respectively.

     Quality. In June 1994, the Company's Quality Assurance System received the
Certificate of Compliance with ISO 9001, the international standard for quality
assurance in design, development, production, installation and servicing.

     Sales and Service. Domestic sales are made primarily through dealers,
direct representatives and exclusive independent distributors, with installation
and service performed by OEC. Most of these distributors have represented OEC
products over many years.

     In Europe, OEC distributes its products primarily through wholly owned
subsidiaries in Italy, France, Germany and Switzerland. For the rest of the
world, distribution is accomplished through independent dealers and
distributors.

     OEC generally warrants its products for twelve months from the date of
installation. OEC offers service contracts for products for which the warranty
has expired.

     During 1997, 1996 and 1995, service revenue represented 11%, 13% and 15% of
net sales, respectively.

     Manufacturing. OEC's manufacturing operations are located in Salt Lake
City, Utah; Warsaw, Indiana, and as of January 1, 1997, Wendelstein, Germany.
The Salt Lake City facility has just been expanded by 40,000 square feet to
accommodate increased product demand and future anticipated growth. The Warsaw,
Indiana facility manufacturers the sheet metal enclosures, the mechanical C-arm
assembly and all major mechanical components for OEC's products. The electronics
and imaging components for the Mini 6600, Series 9600, and Uroview 2600 are
manufactured at OEC's Salt Lake City facility, which also performs final
assembly and test of the finished devices. The Wendelstein, Germany facility
manufactures the Compact 7600 and the Series 7600.

     Competition. The market for mobile X-ray and urological imaging products is
highly competitive. Many of OEC's existing and potential competitors have
substantially greater financial, marketing and technological resources than OEC.
In the market for products similar to OEC's Series 9600 Mobile C-arm, OEC
competes with General Electric, Siemens Medical Systems, Inc., Philips Medical
Systems, Inc. and Toshiba Medical Systems, Inc. Competitive companies offering
products similar to the Mini 6600 include Hologic, Inc., Lunar Corporation, and
XiTec, Inc. The Compact 7600 and Series 7600 compete with similar products from
International Medical Systems, Inc. Competitive companies offering products
similar to the Uroview 2600 include Shimadzu, Picker International, Inc.,
Dornier Medical Systems, Inc. and Liebel-Flarsheim Company. OEC competes on the
basis of price, imaging quality, technological innovation, upgradeability,
reliability and the quality of service and support.

     Backlog. At December 31, 1997, OEC's backlog was approximately $32.3
million, as compared with approximately $24.1 million at December 31, 1996. OEC
includes in backlog only firm orders deliverable within 12 months. Backlog also
includes service contract revenue, which will be earned over the next twelve
months.

     Research and Development. The medical imaging business involves rapid
technological change and innovation. OEC believes that its ability to use
technological innovation to advance the clinical utility of diagnostic imaging
has been and will continue to be a significant factor in its success. OEC has
continued to invest in research and development to identify solutions to the
imaging requirements of the area of minimally invasive medical practices. This
has led to a continuous release of both improvements in existing products and
the introduction of the Series 9600 Mobile Digital Imaging System in 1994 along
with the introduction in 1995 of the Uroview 2600, the Mini 6600 and the Compact
7600. In 1997 OEC introduced the 9600 Mobile Cardiac Cath Lab and the Mini 6600
Dual mode systems.

     During 1997, 1996, and 1995, OEC's research and development expenses
totaled $11.2 million, $8.9 million and $7.7 million, respectively, representing
7.2%, 6.9% and 7.6% of net sales.

     Employees. On December 31, 1997, OEC had approximately 635 employees. None
of OEC's employees are covered by collective bargaining agreements, and OEC
considers its employee relations to be satisfactory.




                                       5
<PAGE>   6

     Acquisitions. During 1995, the Company purchased a 19.8% ownership position
in Barwig Medizinische Systeme GmbH (BMS), a German manufacturer of medical
equipment. The Company was granted exclusive worldwide distribution rights for
the 7600 C-Arm manufactured by BMS. On January 1, 1997, the Company purchased
the remaining outstanding shares of BMS, making it a wholly owned subsidiary of
the Company. Costs associated with this acquisition were not material.

     Risk Factors. The Company's business involves 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.

     Future operating results are dependent on the Company's ability to develop,
manufacture and market innovative products that meet customers' needs. Inherent
in this process are a number of risks that the Company must successfully manage
in order to achieve favorable operating results. 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
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. A failure to obtain protection or the loss
of such protection could have a material adverse effect on the Company's
business.

     Major items that OEC currently purchases from others include video
monitors, X-ray tubes, image intensifiers, CCD cameras and power supplies. Some
of these parts and components are available from a limited number of
single-source manufacturers or suppliers. 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 in cases where the existing inventory of the components is
not adequate to meet the Company's demand for the component during such
disruption and could have a material adverse effect on its financial condition
and results of operations.

     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 regulatory agencies. Failure to comply with FDA and other regulatory
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 audit 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, state and foreign regulations. Nevertheless, there can be no
assurance that the FDA or a state, federal or foreign regulatory agency will
agree with OEC's positions, or that its GMP compliance will not be challenged at
some subsequent point in time. OEC has received approval from the FDA and
foreign regulatory authorities in the past, when required, to market its
products. Regulatory approvals, when granted, may contain significant
limitations on the standards due to unforeseen problems. To date, product
reviews for medical imaging technologies have been obtained within three to four
months. There can be no assurance that OEC will be able to obtain necessary
regulatory approvals in the future, and delays in the receipt of or failure to
receive such approvals, the loss of existing approvals or failure to comply with
regulatory requirements could have a material adverse effect on the business,
financial condition and results of operation of OEC.



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<PAGE>   7

     A portion of the Company's research and development activities, 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.


ITEM 2. PROPERTIES.

     OEC owns its corporate headquarters and manufacturing facility of 145,000
square feet in Salt Lake City, Utah, and leases another 80,000 square feet of
manufacturing in Warsaw, Indiana. The lease expires on June 30, 2000. The
Company has the right to renew this lease for another five years if it so
desires and also has the option to buy. The Company leases 10,000 square feet of
manufacturing in Wendelstein, Germany for the OEC GmbH operations. The lease
expires in October 1998. The company also has the right to renew this lease at
its discretion.


ITEM 3. LEGAL PROCEEDINGS.

     A terminated distributor instituted litigation against the Company in 1986.
The trial court rendered an unfavorable decision in the amount of $3.1 million
in 1992. As a result of that decision, the Company established a reserve for the
judgment. The Company appealed the trial court decision on a number of grounds,
and in November 1993, the appellate court reversed the trial court and held for
the Company on the ground that the distributor had released his claims against
the Company in the settlement of other litigation and did not reach the other
issues raised on appeal. The distributor filed a petition in the Indiana Supreme
Court requesting that the court vacate the appellate court ruling and remand the
case to the appellate court for consideration of the other issues raised on
appeal. On December 31, 1996, the Indiana Supreme Court reversed the ruling of
the Indiana Circuit Court of Appeals and held that the trial court correctly
determined that the release executed by the distributor did not release the
Company. The case was remanded back to the appellate court for consideration of
the remaining issues raised on the appeal. On December 23, 1997 the appellate
court affirmed the trial court's judgement "in all matters except the
prejudgment interest which was reversed." As of December 31, 1997, the reserve
with accrued interest totaled approximately $4.7 million.

     OEC is also a defendant in other ordinary commercial litigation. In light
of available insurance and reserves, management believes that such litigation
will not have a material effect on OEC's business or financial condition.

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

     No matters were submitted to a vote of the Company's Security Holders
during the fourth quarter of fiscal year 1997.


EXECUTIVE OFFICERS OF THE REGISTRANT

<TABLE>
<CAPTION>
Name                               Age        Position
----                               ---        --------
<S>                                <C>        <C>
Joseph W. Pepper                   51         President and Chief Executive Officer
Randy W. Zundel                    42         Chief Operating Officer, Chief Financial Officer
                                              Executive Vice President
Barry K. Hanover                   43         Chief Technical Officer and
                                              Executive Vice President, Engineering
Larry E. Harrawood                 50         Vice President, Marketing and Business Development
Ted L. Parrot                      56         Vice President, Regulatory Affairs & Quality Assurance
Clarence R. Verhoef                42         Vice President, Finance, Treasurer & Secretary
</TABLE>

     Joseph W. Pepper was named President and Chief Executive Officer, and
appointed to the Board of Directors of OEC Medical Systems, Inc., in May of
1997. Prior to joining OEC, he was President of the Medical Devices



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<PAGE>   8

Division of Ohmeda, Inc., from 1995 to 1997. From 1992 to 1995 he was President
of Ohmeda's Medical Systems Division, and from 1988 to 1992 he was Vice
President in charge of the Monitoring Business Unit. Prior to that, Pepper held
engineering management positions at General Electric and at the Electric Power
Research Institute. He is a director on the board of Heartlab, Inc.

     Randy W. Zundel is an Executive Vice President and the Chief Operating
Officer and the Chief Financial Officer of the Company. He was appointed Chief
Operating Officer in September 1996. He has been the Chief Financial Officer of
the Company since October 1993. He was the Chief Operating Officer from February
1990 to September 1993. Prior to that he was Vice President, Operations from May
1987 to February 1990. Mr. Zundel has held various other positions with OEC
since 1981. He is also a director of Orbtek, a start-up opthamalogy company.

     Barry K. Hanover is the Chief Technical Officer and Executive Vice
President, Engineering of the Company. He was appointed Chief Technical Officer
in September 1996. He has been the Vice President, Engineering since December
1992. Previously, he was Director, Mechanical Engineering from October 1992 to
December 1992. Prior to that, he was President of Hanover Engineering Services,
an engineering consulting firm, from June 1992 to October 1992, and Vice
President, Technical Development and member of the Board of Directors of Sarcos,
Inc., a biomedical technology company from 1988 through 1992.

     Larry E. Harrawood has been Vice President, Marketing and Business
Development of the Company since July 1987. Previously, he was Vice President,
Business Development from October 1986 to July 1987, Vice President, Sales and
Marketing from July 1985 to October 1986, and General Manager of X-ray
operations from December 1972 to July 1985.

     Ted L. Parrot was named Vice President, Quality Systems and Regulatory
Affairs in 1994. Prior to joining OEC he held various positions at PPG
Biomedical Systems including Director of Marketing, Director of Engineering and
Director of Quality Assurance and Regulatory Affairs. He has 30 years experience
in the field of diagnostic imaging including 20 years with Philips Medical
Systems.

     Clarence R. Verhoef has been Vice President, Finance since September 1996
and Treasurer since October 1993. He was appointed Secretary in March 1998. Mr.
Verhoef held the positions of Director of Finance, from August 1993 to September
1996, Assistant Secretary from August 1993 to March 1998 and Controller from
October 1989 to August 1993. He has held various other positions with OEC since
1977.

     During 1997, Ruediger Naumann-Etienne resigned the position of President
and Chief Executive Officer upon the hiring of Joseph W. Pepper. Dr.
Naumann-Etienne remains the Chairman of the Board for OEC Medical Systems, Inc.
Also in 1997, Gary Kilman resigned the post of Vice President of Sales.


                                     PART II


ITEM 5. MARKET FOR REGISTRANT'S COMMON EQUITY AND RELATED STOCKHOLDER MATTERS.

     The Company's common stock is presently traded on the New York Stock
Exchange under the trading symbol OXE. Prices shown are the range of high and
low closing prices per share on the New York Stock Exchange -- Composite
Transactions, as reported by the Wall Street Journal. On March 1, 1998, the
number of holders of record of common stock was 2,036.

<TABLE>
<CAPTION>
   Prices
Quarter Ended:                      High              Low            Close
-------------                       ----              ---            -----
<S>                                <C>                <C>            <C>
March 31, 1996...................  13 3/4             9 1/2          11 3/4
June 30, 1996....................  13 5/8            11 1/4          13 5/8
September 30, 1996...............  13 1/2            10 3/4          12 1/2
December 31, 1996................  16 7/8            12 1/4          15


March 31, 1997...................  18 1/2            14 7/8          16 3/8
June 30, 1997....................  17 15/16          13 3/8          17 13/16
September 30, 1997...............  19 3/8            15 3/8          18 7/8
December 31, 1997................  20 13/16          16 11/16        19 15/16
</TABLE>



                                       8
<PAGE>   9

     The Company has not paid any dividends on its common stock. The Company
presently intends to retain all earnings for use in the business and, therefore,
does not anticipate paying any cash dividends in the foreseeable future.


ITEM 6. SELECTED FINANCIAL DATA.

     The table labeled "Five Year Summary" appearing as page 18 of Exhibit 13 is
incorporated herein by reference.


ITEM 7. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS
        OF OPERATIONS

     The section labeled "Management's Discussion and Analysis of Financial
Condition and Results of Operations" appearing as pages 19 through 23 of Exhibit
13 is incorporated herein by reference.


ITEM 8. FINANCIAL STATEMENTS AND SUPPLEMENTAL DATA.

     The Consolidated Financial Statements and Notes thereto appearing at pages
27 through 35 of Exhibit 13 are incorporated herein by reference.


ITEM 9. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND
        FINANCIAL DISCLOSURE.

     Not applicable.


                                    PART III

ITEM 10. DIRECTORS AND EXECUTIVE OFFICERS OF REGISTRANT

     Information concerning the directors of the Company is incorporated by
reference to the sections titled "Information with Respect to Nominees" and in
the definitive Proxy Statement to be filed in connection with the Annual Meeting
of Stockholders (the "1997 Proxy Statement"). Information regarding executive
officers is set forth in Part I of this report.

     Pursuant to Section 16(b) of the Securities Act of 1934, the Company's
directors, its executive (and certain other) officers, and any persons holding
more than 10 percent of the Company's stock are required to report their
ownership and any changes in beneficial ownership of the Company's stock to the
Securities and Exchange Commission and to the New York Stock Exchange. Specific
due dates for these reports have been established and the Company is required to
report any failure to file by these dates.


ITEM 11. EXECUTIVE COMPENSATION

     Information concerning management compensation is incorporated by reference
to the section titled "Cash Compensation of Executive Officers" in the 1997
Proxy Statement.

ITEM 12. SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT

     Information concerning the stock ownership of each person known to the
Company to be a beneficial owner of five percent or more of the Company's Common
Stock and management is incorporated by reference to the sections titled
"Information with Respect to Nominees" and "Principal Stockholders" in the 1997
Proxy Statement.



                                       9
<PAGE>   10

ITEM 13. CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS

     Information concerning relationships and related transactions is
incorporated by reference to the section titled "Transactions with Management
and Others" in the 1997 Proxy Statement.


                                     PART IV

ITEM 14. EXHIBITS, FINANCIAL STATEMENT SCHEDULES AND REPORTS ON FORM 8-K

     (a) 1. Index to Financial Statements

     The following consolidated financial statements of the Company are included
in Exhibit 13 of this Form 10-K:


<TABLE>
<CAPTION>
                                                                                                        Page in
                                                                                                       Exhibit 13
                                                                                                       ----------
<S>                                                                                                    <C>
Consolidated statements of operations for each of the three years in the
       period ended December 31, 1997.................................................................     24

Consolidated balance sheets at December 31, 1997 and 1996.............................................     25

Consolidated statements of stockholders' equity for each of the three years in
       the period ended December 31, 1997.............................................................     26

Consolidated statements of cash flows for each of the three years in the
       period ended December 31, 1997.................................................................     27

Notes to consolidated financial statements............................................................     28

Independent Auditors' Report..........................................................................     36
</TABLE>


     2. Index to Financial Statement Schedule

     All schedules have been omitted since the required information is not
present or is not present in amounts sufficient to require submission of the
schedule, or because the information required is included in the consolidated
financial statements, including the notes thereto.












                                       10
<PAGE>   11

3.   Index to Exhibits

     The following exhibits (numbered in accordance with Item 601 of SEC
     Regulation S-K) are filed as part of this report or are incorporated by
     reference as indicated below.

<TABLE>
<CAPTION>
Exhibit
Number                         Description
-------                        -----------
<S>     <C>
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 10-K, filed March 30, 1994.

10.15    Form of Option Agreement used in connection with options having
         milestone provisions. Incorporated by reference to the OEC Medical
         Systems, Inc. Form 10-K, filed March 30, 1994.

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 10-K, filed March 30, 1994.

10.19    Note and Stock Pledge Agreement between Ruediger Naumann-Etienne and
         OEC Medical Systems, Inc., dated September 5, 1995. Incorporated by
         reference to the OEC Medical Systems, Inc. Form 10-K, filed April 1,
         1996.

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.
</TABLE>



                                       11
<PAGE>   12

<TABLE>
<CAPTION>
Exhibit
Number                         Description
-------                        -----------
<S>     <C>
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.

11       Statement of Computation of Per Share Earnings.

13       Portions of the 1997 Annual Report to Shareholders, including Five Year
         Summary, Management's Discussion & Analysis of Financial Condition and
         Results of Operations, and Consolidated Financial Statements and Notes
         thereto.

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

23       Independent Auditor's Consent.

27.1     Financial Data Schedule (FDS) for Edgar Filing.

27.2     Restated Financial Data Schedule (FDS) for Edgar Filing for 1996.

27.3     Restated Financial Data Schedule (FDS) for Edgar Filing for 3rd
         quarter 1996.

27.4     Restated Financial Data Schedule (FDS) for Edgar Filing for 2nd
         quarter 1996.

27.5     Restated Financial Data Schedule (FDS) for Edgar Filing for 1st
         quarter 1996.

27.6     Restated Financial Data Schedule (FDS) for Edgar Filing for 1995.

27.7     Restated Financial Data Schedule (FDS) for Edgar Filing for 3rd
         quarter 1997.

27.8     Restated Financial Data Schedule (FDS) for Edgar Filing for 2nd
         quarter 1997.

27.9     Restated Financial Data Schedule (FDS) for Edgar Filing for 1st
         quarter 1997.

         (b) Reports on Form 8-K:

             Not applicable
</TABLE>












                                       12
<PAGE>   13

                                   SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) 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.

                                        By: /s/ Randy W. Zundel
                                            ------------------------------------
                                            Randy W. Zundel
                                            Executive Vice President &
                                            Chief Financial Officer


                                POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears
below constitutes and appoints Joseph W. Pepper and Clarence R. Verhoef and each
of them, as his true and lawful attorneys-in-fact and agents, with full power of
substitution and resubstitution, for him and in his name, place and stead, in
any and all capacities, to sign any and all amendments (including post-effective
amendments) to this Report and form 10-K, and to file the same, with all
exhibits thereto, and other documents in connection therewith, with the
Securities and Exchange Commission, granting unto said attorneys-in-fact and
agents, and each of them, full power and authority to do and perform each and
every act and thing requisite and necessary to be done in connection therewith,
as fully to all intents and purposes as he might or could do in person, hereby
ratifying and confirming all that said attorneys-in-fact and agents, or any of
them, or their or his substitute or substitutes, may lawfully do or cause to be
done by virtue hereof.

Date:  March 26, 1998

     Pursuant to the requirements of the Securities Exchange Act of 1934, this
report has been signed below by the following persons on behalf of the
registrant and in the capacities and on the date indicated.

<TABLE>

<S>                                    <C>                        <C>
 /s/ Ruediger Naumann-Etienne          Chairman of the Board      March 26, 1998
------------------------------
     Ruediger Naumann-Etienne


   /s/ Gregory K. Hinckley                   Director             March 26, 1998
------------------------------
       Gregory K. Hinckley


      /s/ Benno P. Lotz                      Director             March 26, 1998
------------------------------
          Benno P. Lotz


      /s/ Allan W. May                       Director             March 26, 1998
------------------------------
          Allan W.  May


    /s/ Chase N. Peterson                    Director             March 26, 1998
------------------------------
        Chase N. Peterson


     /s/ Joseph W. Pepper                    Director             March 26, 1998
------------------------------            President & CEO
         Joseph W. Pepper


     /s/ Randy W. Zundel               Principal Financial &      March 26, 1998
------------------------------          Accounting Officer
         Randy W. Zundel
</TABLE>



                                       13
<PAGE>   14

<TABLE>
<CAPTION>
Exhibit
Number                         Description
-------                        -----------
<S>     <C>
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 10-K, filed March 30, 1994.

10.15    Form of Option Agreement used in connection with options having
         milestone provisions. Incorporated by reference to the OEC Medical
         Systems, Inc. Form 10-K, filed March 30, 1994.

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 10-K, filed March 30, 1994.

10.19    Note and Stock Pledge Agreement between Ruediger Naumann-Etienne and
         OEC Medical Systems, Inc., dated September 5, 1995. Incorporated by
         reference to the OEC Medical Systems, Inc. Form 10-K, filed April 1,
         1996.

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.
</TABLE>



<PAGE>   15

<TABLE>
<CAPTION>
Exhibit
Number                         Description
-------                        -----------
<S>     <C>

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.

11       Statement of Computation of Per Share Earnings.

13       Portions of the 1997 Annual Report to Shareholders, including Five Year
         Summary, Management's Discussion & Analysis of Financial Condition and
         Results of Operations, and Consolidated Financial Statements and Notes
         thereto.

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

23       Independent Auditor's Consent.

27.1     Financial Data Schedule (FDS) for Edgar Filing.

27.2     Restated Financial Data Schedule (FDS) for Edgar Filing for 1996.

27.3     Restated Financial Data Schedule (FDS) for Edgar Filing for 3rd
         quarter 1996.

27.4     Restated Financial Data Schedule (FDS) for Edgar Filing for 2nd
         quarter 1996.

27.5     Restated Financial Data Schedule (FDS) for Edgar Filing for 1st
         quarter 1996.

27.6     Restated Financial Data Schedule (FDS) for Edgar Filing for 1995.

27.7     Restated Financial Data Schedule (FDS) for Edgar Filing for 3rd
         quarter 1997.

27.8     Restated Financial Data Schedule (FDS) for Edgar Filing for 2nd
         quarter 1997.

27.9     Restated Financial Data Schedule (FDS) for Edgar Filing for 1st
         quarter 1997.

         (b) Reports on Form 8-K:

             Not applicable
</TABLE>