<Page> EXHIBIT 4.5 SECOND SUPPLEMENTAL INDENTURE This Second Supplemental Indenture, dated as of December 20, 2002 (this "SUPPLEMENTAL INDENTURE" or "GUARANTEE"), among Brunswick Diagnostic Imaging, LLC, a Georgia limited liability company (the "GUARANTOR"), MedQuest, Inc. (together with its successors and assigns, the "COMPANY"), MQ Associates, Inc. ("HOLDINGS"), the subsidiaries of the Company party to the Indenture (as hereinafter defined) (the "SUBSIDIARY GUARANTORS") and Wachovia Bank, National Association, as Trustee under the Indenture referred to below. WITNESSETH: WHEREAS, the Company, Holdings, the Subsidiary Guarantors and the Trustee have heretofore executed and delivered an Indenture, dated as of August 15, 2002 (as amended, supplemented, waived or otherwise modified, the "INDENTURE"), providing for the issuance of an aggregate principal amount of $180,000,000 of 11 7/8% Senior Subordinated Notes due 2012 of the Company (the "SECURITIES") WHEREAS, SECTION 3.12 of the Indenture provides that unless such Subsidiary has previously issued a Notes Guarantee which is then in full force and effect, the Company is required to cause each Subsidiary that issues a Guarantee in respect of obligations under a Credit Facility to execute and deliver to the Trustee a supplemental indenture pursuant to which such Restricted Subsidiary will unconditionally Guarantee, on a joint and several basis with the other Guarantors, the full and prompt payment of, premium, if any, and interest on the Securities; and WHEREAS, pursuant to SECTION 9.1 of the Indenture, the Trustee and the Company are authorized to execute and deliver this Supplemental Indenture to amend the Indenture, without the consent of any Securityholder; NOW, THEREFORE, in consideration of the foregoing and for other good and valuable consideration, the receipt of which is hereby acknowledged, the Guarantor, the Company, Holdings, the other Subsidiary Guarantors and the Trustee mutually covenant and agree for the equal and ratable benefit of the Holders of the Securities as follows: ARTICLE I DEFINITIONS 1.1 DEFINED TERMS. As used in this Supplemental Indenture, terms defined in the Indenture or in the preamble or recital hereto are used herein as therein defined, except that the term "HOLDERS" in this Guarantee shall refer to the term "Securityholders" as defined in the Indenture and the Trustee acting on behalf or for the benefit of such Holders. The words "herein," "hereof" and "hereby" and other words of similar import used in this Supplemental Indenture refer to this Supplemental Indenture as a whole and not to any particular section hereof. <Page> ARTICLE II AGREEMENT TO BE BOUND; GUARANTEE 2.1 AGREEMENT TO BE BOUND. The Guarantor hereby becomes a party to the Indenture as a Subsidiary Guarantor and as such will have all of the rights and be subject to all of the obligations and agreements of a Subsidiary Guarantor under the Indenture. The Guarantor agrees to be bound by all of the provisions of the Indenture applicable to a Subsidiary Guarantor and to perform all of the obligations and agreements of a Subsidiary Guarantor under the Indenture. 2.2 GUARANTEE. The Guarantor as of the Guarantor Effective Date (as hereinafter defined) hereby fully, unconditionally and irrevocably guarantees, as primary obligor and not merely as surety, jointly and severally with each other Subsidiary Guarantor, to each Holder of the Securities and the Trustee, the full and punctual payment when due, whether at maturity, by acceleration, by redemption, or otherwise, of the Obligations pursuant to ARTICLE XI of the Indenture. ARTICLE III MISCELLANEOUS 3.1 NOTICES. All notices and other communications to the Guarantor shall be given as provided in the Indenture to the Guarantor, at its address set forth below, with a copy to the Company as provided in the Indenture for notices to the Company. 3.2 PARTIES. Nothing expressed or mentioned herein is intended or shall be construed to give any Person, firm or corporation, other than the Holders and the Trustee, any legal or equitable right, remedy or claim under or in respect of this Supplemental Indenture or the Indenture or any provision herein or therein contained. 3.3 GOVERNING LAW. This Supplemental Indenture shall be governed by, and construed in accordance with, the laws of the State of New York. 3.4 SEVERABILITY CLAUSE. In case any provision in this Supplemental Indenture shall be invalid, illegal or unenforceable, the validity, legality and enforceability of the remaining provisions shall not in any way be affected or impaired thereby and such provision shall be ineffective only to the extent of such invalidity, illegality or unenforceability. <Page> 3.5 RATIFICATION OF INDENTURE; SUPPLEMENTAL INDENTURES PART OF INDENTURE. Except as expressly amended hereby, the Indenture is in all respects ratified and confirmed and all the terms, conditions and provisions thereof shall remain in full force and effect. This Supplemental Indenture shall form a part of the Indenture for all purposes, and every Holder of Securities heretofore or hereafter authenticated and delivered shall be bound hereby. The Trustee makes no representation or warranty as to the validity or sufficiency of this Supplemental Indenture. 3.6 COUNTERPARTS. The parties hereto may sign one or more copies of this Supplemental Indenture in counterparts, all of which together shall constitute one and the same agreement. 3.7 HEADINGS. The headings of the Articles and the sections in this Supplemental Indenture are for convenience of reference only and shall not be deemed to alter or affect the meaning or interpretation of any provisions hereof. 3.8 ADDITIONAL DEFINITIONS. As used in this Second Supplemental Indenture, "GUARANTOR EFFECTIVE DATE" shall mean December 20, 2002. [signature page follows] <Page> IN WITNESS WHEREOF, the parties hereto have caused this Supplemental Indenture to be duly executed as of the date first above written. BRUNSWICK DIAGNOSTIC IMAGING, LLC, as a Guarantor By: /s/ J. KENNETH LUKE ------------------- Name: J. Kenneth Luke Title: Manager WACHOVIA BANK NATIONAL ASSOCIATION, as Trustee By: /s/ ERIC J. KNOLL ----------------- Name: Eric J. Knoll Title: Assistant Vice President MEDQUEST, INC. By: /s/ J. KENNETH LUKE ------------------- Name: J. Kenneth Luke Title: President MQ ASSOCIATES, INC. By: /s/ J. KENNETH LUKE ------------------- Name: J. Kenneth Luke Title: President <Page> <Table> IMAGING SERVICES OF ALABAMA, INC. KENOSHA DIAGNOSTIC IMAGING, INC. ANDERSON DIAGNOSTIC IMAGING, INC. LEXINGTON OPEN MRI, INC. ASHEVILLE OPEN MRI, INC. MECKLENBURG OPEN MRI, INC. BIOIMAGING AT CHARLOTTE, INC. MEDQUEST ASSOCIATES, INC. BIOIMAGING AT HARDING, INC. MISSOURI IMAGING, INC. BIOIMAGING OF COOL SPRINGS, INC. MOBILE OPEN MRI, INC. CABARRUS DIAGNOSTIC IMAGING, INC. OCCUPATIONAL SOLUTIONS, INC. CAPE FEAR DIAGNOSTIC IMAGING, INC. PALMETTO IMAGING, INC. CAROLINA IMAGING, INC. OF FAYETTEVILLE PHOENIX DIAGNOSTIC IMAGING, INC. CHAPEL HILL DIAGNOSTIC IMAGING, INC. PIEDMONT IMAGING, INC. (FORSYTH) CHATTANOOGA DIAGNOSTIC IMAGING, INC. PIEDMONT IMAGING, INC. (SPARTANBURG) DOTHAN DIAGNOSTIC IMAGING, INC. OPEN MRI & IMAGING OF RICHMOND, INC. FLORIDA DIAGNOSTIC IMAGING CENTER, INC. SOUTH CAROLINA DIAGNOSTIC IMAGING, INC. OPEN MRI OF GEORGIA, INC. SUN VIEW HOLDINGS, INC. OPEN MRI & IMAGING OF GEORGIA, INC. TEXAS IMAGING SERVICES OF EL PASO, INC. GROVE DIAGNOSTIC IMAGING CENTER, INC. TRIAD IMAGING, INC. KANSAS DIAGNOSTIC IMAGING, INC. TYSON'S CORNER DIAGNOSTIC IMAGING, INC. NORTHEAST COLUMBIA DIAGNOSTIC IMAGING, INC. VIRGINIA DIAGNOSTIC IMAGING, INC. WISCONSIN DIAGNOSTIC IMAGING, INC. OPEN MRI OF THE CAROLINAS, INC. VIENNA DIAGNOSTIC IMAGING, INC. On behalf of each of the entities listed above: On behalf of each of the entities listed above: </Table> By: /s/ J. KENNETH LUKE By: /s/ J. KENNETH LUKE ------------------- ------------------- Name: J. Kenneth Luke Name: J. Kenneth Luke Title: President Title: President <Page> <Table> OPEN MRI & IMAGING OF ALBANY, LLC WOODSTOCK DIAGNOSTIC IMAGING, LLC OPEN MRI & IMAGING OF ATHENS, LLC DIAGNOSTIC IMAGING OF HIRAM, LLC ATHENS MRI, LLC DIAGNOSTIC IMAGING OF MARIETTA, LLC OPEN MRI OF ATLANTA, LLC MONTGOMERY OPEN MRI, LLC BUCKHEAD DIAGNOSTIC IMAGING, LLC NORWOOD DIAGNOSTIC IMAGING, LLC OPEN MRI OF CENTRAL GEORGIA, LLC COASTAL IMAGING, LLC IMAGING CENTER OF CENTRAL GEORGIA, LLC DURHAM DIAGNOSTIC IMAGING, LLC OPEN MRI & IMAGING OF CONYERS, LLC JACKSONVILLE DIAGNOSTIC IMAGING, LLC CUMMING DIAGNOSTIC IMAGING, LLC CAPE IMAGING, L.L.C. OPEN MRI & IMAGING OF DEKALB, LLC BRIDGETON MRI AND IMAGING CENTER, LLC DULUTH DIAGNOSTIC IMAGING, LLC KIRKWOOD MRI AND IMAGING CENTER, LLC DULUTH CT CENTER, LLC ST. PETERS MRI & IMAGING CENTER, LLC DIAGNOSTIC IMAGING OF ATLANTA, LLC OPEN MRI & IMAGING OF RICHMOND, LLC OPEN MRI & IMAGING OF NORTH FULTON, LLC RICHMOND WEST END DIAGNOSTIC IMAGING, LLC OPEN MRI & IMAGING OF N.E. GEORGIA, LLC CAROLINA MEDICAL IMAGING, LLC DIAGNOSTIC IMAGING OF GEORGIA, LLC OPEN MRI OF SIMPSONVILLE, LLC MIDTOWN DIAGNOSTIC IMAGING, LLC SIMPSONVILLE OPEN MRI, LLC OPEN MRI & IMAGING OF DOUGLASVILLE, LLC EAST COOPER DIAGNOSTIC IMAGING, LLC HAPEVILLE DIAGNOSTIC IMAGING, LLC FARMFIELD DIAGNOSTIC IMAGING, LLC OPEN MRI & IMAGING OF MACON, LLC FORT MILL DIAGNOSTIC IMAGING, LLC OPEN MRI AND IMAGING OF SNELLVILLE, LLC TRICOM DIAGNOSTIC IMAGING, LLC WEST PACES DIAGNOSTIC IMAGING, LLC WEST ASHLEY DIAGNOSTIC IMAGING, LLC TOWN & COUNTRY OPEN MRI, LLC CLAYTON OPEN MRI, LLC On behalf of each of the entities listed above: On behalf of each of the entities listed above: </Table> By: /s/ J. KENNETH LUKE By: /s/ J. KENNETH LUKE ------------------- ------------------- Name: J. Kenneth Luke Name: J. Kenneth Luke Title: Manager Title: Manager <Page> OPEN MRI & IMAGING OF FLORENCE, LLC OPEN MRI OF MYRTLE BEACH, LLC Palmetto Imaging, Inc., as sole member of each of the entities listed above By: /s/ J. KENNETH LUKE ------------------- Name: J. Kenneth Luke Title: President