<PAGE>
                                                                  EXHIBIT 10.15A

                                  EMAGEON, INC.
                         FIRST AMENDMENT AND JOINDER TO
                   AMENDED AND RESTATED STOCKHOLDERS AGREEMENT

         THIS FIRST AMENDMENT AND JOINDER ("Amendment") to the Amended and
Restated Stockholders Agreement of Emageon, Inc., dated October 2, 2001 (the
"Agreement"), is made as of May 30, 2003, by and among EMAGEON, INC., a Delaware
corporation (the "Company") and the undersigned holders of the Company's Common
Stock, Series A Preferred Stock, Series B Preferred Stock, Series B-1 Preferred
Stock, and Series C Preferred Stock that are parties to the Agreement, and the
undersigned parties holding all of the Company's outstanding shares of Series D
Preferred Stock. Capitalized terms used herein but not otherwise defined shall
have the meanings given to such terms in the Agreement.

                                   WITNESSETH:

         WHEREAS, the Common Stockholders, Series A Investors, Series B
Investors, Series B-1 Investors, and Series C Investors (collectively, the
"Existing Parties") are parties to the Agreement;

         WHEREAS, pursuant to Section 15(e) of the Agreement, any term of the
Agreement may be amended with the written consent of (i) the Company, (ii) the
Investors (or their transferees) holding a majority of the outstanding shares of
Preferred Stock (voting together as a single class) and (iii) the Common
Stockholders (or their transferees) holding a majority of the outstanding shares
of Common Stock, and any amendment effected in accordance with such Section
15(e) of the Agreement shall be binding upon the Company, the Common
Stockholders, and the Investors and each of their future transferees;

         WHEREAS, the Company desires to amend the Agreement;

         WHEREAS, the undersigned Existing Parties, which hold a majority of the
outstanding shares of Preferred Stock and a majority of the outstanding shares
of Common Stock, desire to amend the Agreement; and

         WHEREAS, the undersigned holders of all of the outstanding shares of
the Company's Series D Preferred Stock desire to become parties to the
Agreement, as amended by this Amendment.

         NOW, THEREFORE, in consideration of the premises, and the mutual terms
and conditions set forth herein, it is hereby agreed by and among the Company,
the Common Stockholders, the Series A Investors, Series B Investors, Series B-1
Investors, and Series C Investors that the Agreement is hereby amended in
accordance with this Amendment, and the undersigned holders of all of the
outstanding shares of the Company's Series D Preferred Stock shall become
parties to the Agreement, as amended by this Amendment:


<PAGE>

1.       AMENDMENTS.

         (A)      The initial paragraph of the Agreement is hereby deleted in
its entirety and replaced with the following:

         "THIS AMENDED AND RESTATED STOCKHOLDERS AGREEMENT ("Agreement"), made
         this 2nd day of October, 2001, by and among EMAGEON, INC., a Delaware
         corporation (the "Company"); those holders of the Company's Common
         Stock listed on Schedule 1 attached hereto (the "Common Stockholders");
         those holders of the Company's Series A Preferred Stock listed on
         Schedule 2 attached hereto (the "Series A Investors"); those holders of
         the Company's Series B Preferred Stock listed on Schedule 3 attached
         hereto (the "Series B Investors"); those holders of the Company's
         Series B-1 Preferred Stock listed on Schedule 4 attached hereto (the
         "Series B-1 Investors"); those holders of the Company's Series C
         Preferred Stock listed on Schedule 5 attached hereto (the "Series C
         Investors"); and those holders of the Company's Series D Preferred
         Stock listed on Schedule 6 attached hereto (the "Series D Investors",
         and together with the Series A Investors, the Series B Investors, the
         Series B-1 Investors and the Series C Investors collectively, the
         "Investors")."

         (B)      The third "WHEREAS" clause of the Agreement is hereby deleted
in its entirety and replaced with the following:

         "WHEREAS, the Series A Investors are the holders of all of the issued
         and outstanding shares of the Company's Series A Preferred Stock,
         $0.001 par value (the "Series A Preferred"), the Series B Investors are
         the holders of all of the issued and outstanding shares of the
         Company's Series B Preferred Stock, $0.001 par value (the "Series B
         Preferred"), the Series B-1 Investors are the holders of all of the
         issued and outstanding shares of the Company's Series B-1 Preferred
         Stock, $0.001 par value (the "Series B-1 Preferred"), the Series C
         Investors are the holders of all of the issued and outstanding shares
         of the Company's Series C Preferred Stock, $0.001 par value (the
         "Series C Preferred"), and the Series D Investors are the holders of
         all of the issued and outstanding shares of the Company's Series D
         Preferred Stock, $0.001 par value (the "Series D Preferred", and
         together with the Series A Preferred, Series B Preferred, Series B-1
         Preferred and Series C Preferred, collectively, the "Preferred
         Stock")."

         (C)      Section 2(d) of the Agreement is hereby deleted in its
entirety and replaced with the following:

         "(D) OFFER TO SERIES B INVESTORS, SERIES B-1 INVESTORS, SERIES C
         INVESTORS AND SERIES D INVESTORS. In the event the Company shall decide
         not to purchase all the Offered Shares, Company shall notify each of
         the Series B Investors, Series B-1 Investors, Series C Investors and
         Series D Investors of such decision within thirty (30) days after
         receipt of the Notice. The Series B Investors, Series B-1 Investors,
         Series C Investors and Series D Investors shall have the right to


                                       2
<PAGE>

         purchase all (or any portion) of the Offered Shares in accordance with
         the terms set forth in the Notice on a pro rata basis determined by
         each such party's proportionate ownership interest of all outstanding
         Shares held by the Series B Investors, Series B-1 Investors, Series C
         Investors and Series D Investors. In the event a Series B Investor,
         Series B-1 Investor, Series C Investor or Series D Investor elects not
         to acquire its (or their) entire proportionate interest, the remaining
         Series B Investors, Series B-1 Investors, Series C Investors and Series
         D Investors shall be entitled to acquire the remainder of such interest
         on a pro rata basis as described above; provided, however, that such
         Investors must notify the Selling Stockholder (and the Company) of
         their intention to purchase such shares within thirty (30) days from
         the date the Notice was delivered to the Company and the Series B
         Investors, Series B-1 Investors, Series C Investors and Series D
         Investors. Investors holding a majority of the issued and outstanding
         Series B Preferred, Series B-1 Preferred, Series C Preferred and Series
         D Preferred (voting together as a single class) may waive for such
         Investors the rights of first refusal contained herein if such
         Investors deem the transfer of the Shares of the Selling Stockholder to
         the person named in the Notice to be in the best interest of the
         Investors and/or Company."

         (D)      The first sentence of Section 2(e) of the Agreement is hereby
deleted in its entirety and replaced with the following:

         "In the event the Company, the Series B Investors, Series B-1
         Investors, Series C Investors and Series D Investors shall decide not
         to purchase all the Offered Shares, Company shall notify each of the
         Series A Investors and Common Stockholders of such decision within
         thirty (30) days after receipt of the Notice."

         (E)      The first sentence of Section 3(a) of the Agreement is hereby
deleted in its entirety and replaced with the following:

         "In the event of a Sale of the Company, as hereinafter defined, which
         is approved by the holders of at least 60% of the then-outstanding
         Series B Preferred, Series B-1 Preferred, Series C Preferred and Series
         D Preferred (voting together as a single class on an as-converted
         basis), each Investor and each Common Stockholder shall vote all shares
         of Preferred Stock and/or Common Stock (including Shares of Common
         Stock issued upon conversion of Preferred Stock) held by him or it in
         favor of the Sale of the Company."

         (F)      Section 5 of the Agreement is hereby deleted in its entirety
and replaced with the following:

         "5. PROHIBITION AGAINST PLEDGE OF STOCK. No Common Stockholder or
         Investor shall pledge, hypothecate or grant a security interest in all
         or any part of the Shares (other than pledges, hypothecations or
         security interests granted to lenders in connection with loans to
         purchase Shares) without the consent of the


                                       3
<PAGE>
         holders of at least 60% of the Series B Preferred, Series B-1
         Preferred, Series C Preferred and Series D Preferred (voting together
         as a single class)."

         (G)      Section 6 of the Agreement is hereby amended by adding the
phrase "as amended" after the phrase "October 2, 2001".

         (H)      Section 7(a) of the Agreement is hereby deleted and replaced
with the following:

         "(A) CONSTITUENCY OF BOARD OF DIRECTORS; QUORUM. Pursuant to the
         Amended and Restated Certificate of Incorporation of the Company (the
         "Certificate"), the Common Stockholders and Investors shall vote their
         shares of capital stock of Company for a Board of Directors consisting
         of nine (9) directors. For so long as the outstanding Shares of Series
         A Preferred constitute five percent (5%) or more of the Company's
         outstanding capital stock (on a fully diluted basis), the Series A
         Investors, voting separately as a class, shall have the right to elect
         one (1) director (the "Series A Director") (and to fill any vacancies
         with respect thereto) by a vote of a majority of the then outstanding
         shares of Series A Preferred. In connection therewith, the Series A
         Investors shall designate one person as nominee for director and such
         Series A Investors agree to designate and vote their Shares in favor of
         such nominee. For so long as the outstanding Shares of Series B
         Preferred and Series B-1 Preferred, collectively, constitute five
         percent (5%) or more of the Company's outstanding capital stock (on a
         fully diluted basis), the Series B Investors and the Series B-1
         Investors, voting together and separately as a class, shall have the
         right to elect one (1) director (the "Series B Director"). In
         connection therewith, the Series B Investors and Series B-1 Investors
         shall designate one person as nominee for director and such Series B
         Investors and Series B-1 Investors agree to designate and vote their
         Shares in favor of such nominee. The initial Series B Director shall be
         designated by STF Institutional Partners II, L.P. For so long as the
         outstanding Shares of Series C Preferred constitute five percent (5%)
         or more of the Company's outstanding capital stock (on a fully diluted
         basis), the Series C Investors, voting separately as a class, shall
         have the right to elect two (2) directors (the "Series C Directors")
         (and to fill any vacancies with respect thereto) by a vote of a
         majority of the then outstanding shares of Series C Preferred. One (1)
         Series C Director initially shall be designated by Investors holding a
         majority of the Shares of Series C Preferred and the other Series C
         Director shall be Paul Reaves. Each of the Series C Investors shall
         vote their Series C Shares in favor of such designee and such nominee.
         For so long as the outstanding Shares of Series D Preferred constitute
         two and one-half percent (2.5%) or more of the Company's outstanding
         capital stock (on a fully diluted basis), the Series D Investors,
         voting separately as a class, shall have the right to elect one (1)
         director (the "Series D Director") (and to fill any vacancies with
         respect thereto) by a vote of a majority of the then outstanding shares
         of Series D Preferred. The Series D Director initially shall be John
         Thompson. In addition, each party shall vote such party's shares of
         capital stock of the Company to elect (i) Jett as a director while Jett
         remains an employee of Company and (ii) Mark Gehring as a director
         until the earlier of (A) May 30,


                                       4
<PAGE>

         2005, or (B) the date on which the Company files an effective
         registration statement for a Qualifying IPO (as such term is defined in
         the Certificate). Any other members of the Board of Directors
         authorized by the Company's Bylaws shall be elected by the Common
         Stockholders and Investors voting together as a single class. A
         majority of the number of directors then constituting the Board of
         Directors shall constitute a quorum for the transaction of business of
         the Board of Directors.

         (I)      Section 8(a)(i) is hereby deleted in its entirety and replaced
with the following:

         "(i) Reports and Notifications to Be Delivered by Company. Unless
         waived, Company shall furnish to each Investor the following reports
         and notices so long as such holder continues to hold at least 40,000
         Shares (as adjusted for stock dividends, combinations, or splits) of
         Preferred Stock; provided, that, in the case of affiliated Series A
         Investors, Series B Investors, Series B-1 Investors, Series C Investors
         or Series D Investors, Company shall only be obligated to furnish the
         following reports and notices to one representative of such affiliated
         Series A Investors, Series B Investors, Series B-1 Investors, Series C
         Investors or Series D Investors."

         (J)      Section 8(b)(v)(B) is hereby deleted in its entirety and
replaced with the following:

         "(B) Maintain or cause to be maintained a policy or policies of
         directors' and officers' liability insurance with responsible and
         reputable insurance companies or associations, covering the directors
         and officers of Company and its subsidiaries in such amounts and
         against such risks as is customarily carried by companies engaged in
         similar businesses to that of Company, and on such terms and conditions
         as shall be reasonably acceptable to each of the Series A Director, the
         Series B Director, the Series C Director and each Series D Director."

         (K)      Section 8(b)(xv) is hereby deleted in its entirety and
replaced with the following:

         "(xv) Option Plans and Option Shares. The Board of Directors of Company
         shall reserve up to 18,325,000 shares of Common Stock, subject to
         adjustment for stock splits, stock dividends and other changes
         affecting the Common Stock (collectively, the "Option Shares") for
         issuance to Company's directors, officers, employees, advisors and
         consultants pursuant to one or more stock option or other equity
         compensation plans established by Company (each an "Option Plan")
         provided that any such Option Plan which shall be adopted after the
         date hereof shall be adopted only with the approval of the Board of
         Directors, including the approval of the Series B Director, the Series
         D Director and at least one Series C Director. All grants of Option
         Shares by Company to directors, officers, employees, advisors and
         consultants of Company made after the date of this Agreement shall be
         subject to approval of the Compensation Committee of the Board of
         Directors. The number of Option Shares available for issuance may be


                                       5
<PAGE>

         increased with the approval of the Board of Directors (including the
         approval of the Series B Director, the Series D Director and one (1)
         Series C Director) or the Compensation Committee."

         (L)      Section 15(d) is hereby amended by adding the following new
clause (v) after clause (iv):

         "(v) if to a Series D Investor, at such Series D Investor's address as
         set forth on Schedule 6 attached hereto, or at such other address as
         such Series D Investor shall have furnished to the other parties hereto
         in writing."

         (M)      Schedule 1 is hereby amended by adding those Common
Stockholders listed on EXHIBIT A hereto.

         (N)      A new Schedule 6 is hereby added to the Agreement in the form
attached as EXHIBIT B hereto.

2.       JOINDER. Each undersigned holder of Series D Preferred Shares hereby
agrees that upon execution of this Amendment by such person or entity, such
person or entity shall become a party to the Agreement, as amended by this
Amendment, and shall be fully bound by, and subject to, all of the covenants,
terms and conditions of the Agreement, as amended by this Amendment, as though
such person or entity were an original party thereto and shall be deemed a
Series D Investor for all purposes thereof.

3.       GENERAL PROVISIONS.

         (A)      NO OTHER AMENDMENTS. Except for the amendments contained in
SECTION 1 of this Amendment, the Agreement shall remain in full force and
effect.

         (B)      AUTHORIZATION. Each Common Stockholder and Investor (which
term shall include the undersigned holders of the Series D Preferred Shares)
hereby represents and warrants to the Company and to each other that (i) such
Common Stockholder or Investor has full power and authority to execute, to
deliver and to perform such Common Stockholder's or Investor's obligations under
this Amendment; and (ii) the execution and delivery of this Amendment has been
duly and validly authorized, and all necessary action has been taken to make
this Amendment a valid and binding obligation of such Common Stockholder or
Investor, enforceable in accordance with its terms, except that the enforcement
thereof may be subject to bankruptcy, insolvency, reorganization, moratorium or
other similar laws now or hereafter in effect relating to creditors' rights
generally and to general principles of equity (regardless of whether such
enforcement is considered a proceeding in equity or at law).

         (C)      GOVERNING LAW. This Amendment shall be governed by and
construed under the laws of the State of Delaware, as applied to agreements
among Delaware residents made and to be performed entirely within the State of
Delaware, and without regard to the conflicts of law principles as may otherwise
be applicable.


                                       6
<PAGE>

         (D)      BINDING ON SUCCESSORS. This Amendment shall bind and inure to
the benefit of the parties hereto, their respective heirs, executors,
administrators, successors and permitted assigns.

         (E)      COUNTERPARTS AND SIGNATURE BY FACSIMILE. This Amendment may be
executed in two or more counterparts, each of which shall be deemed an original,
but all of which together shall constitute one and the same instrument. The
facsimile signature of any party to this Amendment for purposes of execution or
otherwise is to be considered as an original signature, and the document
transmitted is to be considered to have the same binding effect as an original
signature on an original document. At the request of any party, any facsimile or
telecopy document is to be re-executed in original form by the parties who
executed the facsimile or telecopy document. No party may raise the use of a
facsimile machine or telecopier or the fact that any signature was transmitted
through the use of a facsimile or telecopier machine as a defense to the
enforcement of this Amendment or any notice required thereof.


                    [Signatures begin on the following page.]


                                       7
<PAGE>

         IN WITNESS WHEREOF, the parties have executed this Amendment under seal
as of the day and year first above written.


                                    COMPANY:


                                    EMAGEON, INC.



                                    By: /s/ Charles A. Jett, Jr.
                                        ---------------------------------
                                        Charles A. Jett, Jr., President


<PAGE>










              [Individual Signature Pages of Stockholders Omitted]


<PAGE>

                                    EXHIBIT A

Mark Gehring
John W. Thompson
Roger Chylla
Praveen Sinha
Raymond Kubly
Jeff Rusinow
Tom Plumb
John J. Burke
Marianna Thompson Trust
Herman & Gwen Shapiro Foundation
David G. Walsh
Robert J. Kriz
Thomas Terry
Gary Wendt
GEFUltravisual
James Delaney III Declaration of Trust
J. Maurits Hudig IRA
David and Kim Bethea
MBF Investments (2000) LLC
Philip R. Blake
M&I Trust Co., (FBO Tod B. Linstroth)
Thor Lundgren
Peter Skanavis
Charles F. Stierman
James Riederer
John J. Ouellette
John R. Teitgen
William J. Kalmer CLU, Ltd. Pension Plan
Dennis D. Skogen
John A. Turcott
Michael G. Laskis
Richard T. Daly
Terence F. Kelly
D. King Aymond, M.D.
John and Sally Oulette
Ryan Kubly
Gregory J. Lynch & Eileen K. Schnabel
Cathrine M. Hudig 1972 Trust
Carolyn Bassham 1972 Trust
Barb Rowbotham 1972 Trust
Schuetz Revocable Trust Alvin & Janice Schuetz
Pat Walsh
Dave Reneicke


<PAGE>

Richard Jansen
Henry and Diane Ipsen
Susan P. Daugherty
Greg Larson
Mehta Revocable Trust
Harry Roth
Eric J. Rosenstock
Timothy Reiland
David Wood
Marcus Cohen
Francis M. Corby, Jr.
Gary R. Kuphall
Dennis J. Powers
Whitt C. Case
Jaime Schulz
Richard W. Schulze or Charlene E. Schulze
Norman M. Merz
Philip F. Powondra
Jeffrey O. Jorgenson
James and Joanne Silbernagel Family Trust
Terry Sivesand
Tim O'Brien
Jim Burgess
David Duchow
Dennis Hoffman
Anthony Jasen
Linda A Grey
The Mendota Group
Gregory J. Lynch
Richard A. Latta
John C. Thompson
Ron Reinholtz
Richard Burgess
Parimal


<PAGE>

                                    EXHIBIT B

                                   SCHEDULE 6

                               SERIES D INVESTORS

Mark Gehring
John W. Thompson
Roger Chylla
Praveen Sinha
Raymond Kubly
Jeff Rusinow
Tom Plumb
John J. Burke
Marianna Thompson Trust
Herman & Gwen Shapiro Foundation
David G. Walsh
Robert J. Kriz
Thomas Terry
Gary Wendt
GEFUltravisual
James Delaney III Declaration of Trust
J. Maurits Hudig IRA
David and Kim Bethea
MBF Investments (2000) LLC
Philip R. Blake
M&I Trust Co., (FBO Tod B. Linstroth)
Thor Lundgren
Peter Skanavis
Charles F. Stierman
James Riederer
John J. Ouellette
John R. Teitgen
William J. Kalmer CLU, Ltd. Pension Plan
Dennis D. Skogen
John A. Turcott
Michael G. Laskis
Richard T. Daly
Terence F. Kelly
D. King Aymond, M.D.
John and Sally Oulette
Ryan Kubly
Gregory J. Lynch & Eileen K. Schnabel
Cathrine M. Hudig 1972 Trust
Carolyn Bassham 1972 Trust
Barb Rowbotham 1972 Trust


<PAGE>

Schuetz Revocable Trust Alvin & Janice Schuetz
Pat Walsh
Dave Reneicke
Richard Jansen
Henry and Diane Ipsen
Susan P. Daugherty
Greg Larson
Mehta Revocable Trust
Harry Roth
Eric J. Rosenstock
Timothy Reiland
David Wood
Marcus Cohen
Francis M. Corby, Jr.
Gary R. Kuphall
Dennis J. Powers
Whitt C. Case
Jaime Schulz
Richard W. Schulze or Charlene E. Schulze
Norman M. Merz
Philip F. Powondra
Jeffrey O. Jorgenson
James and Joanne Silbernagel Family Trust
Terry Sivesand
Tim O'Brien
Jim Burgess
David Duchow
Dennis Hoffman
Anthony Jasen
Linda A Grey
The Mendota Group
Gregory J. Lynch
Richard A. Latta
John C. Thompson
Ron Reinholtz
Richard Burgess
Parimal