Exhibit 3.51

                          CERTIFICATE OF INCORPORATION

                                       OF

                COMPREHENSIVE MEDICAL IMAGING-SAN FRANCISCO, INC.

         The undersigned, for the purposes of forming a corporation under the
laws of the State of Delaware, do make, file and record this Certificate, and do
certify that:

         FIRST: The name of this Corporation is Comprehensive Medical
Imaging-San Francisco, Inc.

         SECOND: Its Registered Office in the State of Delaware is to be located
at 9 East Loockerman Street, in the City of Dover, County of Kent, 19901. The
Registered Agent in charge thereof is National Registered Agents, Inc.

         THIRD: The purpose of the Corporation is to engage in any lawful act or
activity for which a corporation may be organized under the General Corporation
Law of Delaware.

         FOURTH: The Corporation is authorized to issue one class of stock to be
designated "Common Stock." The total number of shares which the Corporation is
authorized to issued is One Hundred (100) shares of Common Stock, $0.05 par
value per share.

         FIFTH: No holder of any of the shares of the corporation shall, as such
holder, have any right to purchase or subscribe for any shares of any class
which the corporation may issue or sell, whether or not such shares are
exchangeable for any shares of the corporation of any other class or classes,
and whether such shares are issued out of the number of shares authorized by the
Certificate of Incorporation of the corporation as originally filed, or by any
amendment thereof, or out of shares of the corporation acquired by it after the
issue thereof; nor shall any holder of any of the shares of the corporation, as
such holder, have any right to purchase or subscribe for any obligations which
the corporation may issue or sell that shall be convertible into, or
exchangeable for, any shares of the corporation of any class or classes, or to
which shall be attached or shall appertain to any warrant or warrants or other
instrument or instruments that shall confer upon the holder thereof the right to
subscribe for, or purchase from the corporation any shares of any class or
classes.

         SIXTH: The name and mailing address of the incorporator are as follows:



     NAME                                  MAILING ADDRESS
- --------------                       ----------------------------
                                  
Ricardo Orozco                       2030 Main Street, Suite 1030
                                     Irvine, CA  92614


         SEVENTH: The duration of the corporation shall be perpetual.


         EIGHTH: When a compromise or arrangement is proposed between the
corporation and its creditors or any class of them or between the corporation
and its shareholders or any class of them, a court of equity jurisdiction within
the state, on application of the corporation or of a creditor or shareholder
thereof, or on application of a receiver appointed for the corporation pursuant
to the provisions of Section 291 of Title 8 of the Delaware Code or on
application of trustees in dissolution or of any receiver or receivers appointed
for the corporation pursuant to provisions of Section 279 of Title 8 of the
Delaware Code may order a meeting of the creditors or class of creditors or of
the shareholders or class of shareholders to be affected by the proposed
compromise or arrangement or reorganization, to be summoned in such manner as
the court directs. If a majority in number representing 3/4 in value of the
creditors or class of creditors, or of the shareholders or class of shareholders
to be affected by the proposed compromise or arrangement or a reorganization,
agree to a compromise or arrangement or a reorganization of the corporation as a
consequence of the compromise or arrangement, the compromise or arrangement and
the reorganization, if sanctioned by the court to which the application has been
made, shall be binding on all the creditors or class of creditors, or on all the
shareholders or class of shareholders and also on the corporation.

         NINTH: The personal liability of all of the directors of the
corporation is hereby eliminated to the fullest extent allowed as provided by
the Delaware General Corporation Law, as the same may be supplemented and
amended.

         TENTH: The corporation shall, to the fullest extent legally permissible
under the provisions of the Delaware General Corporation Law, as the same may be
amended and supplemented, indemnify and hold harmless any and all persons whom
it shall have power to indemnify under said provisions from and against any and
all liabilities (including expenses) imposed upon or reasonably incurred by him
in connection with any action, suit or other proceeding in which he may be
involved or with which he may be threatened, or other matters referred to in or
covered by said provisions both as to action in his official capacity and as to
action in another capacity while holding such office, and shall continue as to a
person who has ceased to be a director or officer of the corporation. Such
indemnification provided shall not be deemed exclusive of any other rights to
which those indemnified may be entitled under any Bylaw, Agreement or Resolution
adopted by the shareholders entitled to vote thereon after notice.

Dated on this 28th day of June 2000.

                                     /s/ Ricardo Orozco
                                     -------------------------------------------
                                     Ricardo Orozco
                                     Sole Incorporator

                                       2


             CERTIFICATE OF CHANGE OF LOCATION OF REGISTERED OFFICE
                             AND OF REGISTERED AGENT

                COMPREHENSIVE MEDICAL IMAGING-SAN FRANCISCO, INC.

It is hereby certified that:

         1. The name of the corporation (hereinafter called the "corporation")
is:

                COMPREHENSIVE MEDICAL IMAGING-SAN FRANCISCO, INC.

         2. The registered office of the corporation within the State of
Delaware is hereby changed to 2711 Centerville Road, Suite 400, City of
Wilmington 19808, County of New Castle.

         3. The registered agent of the corporation within the State of Delaware
is hereby changed to Corporation Service Company, the business office of which
is identical with the registered office of the corporation as hereby changed.

         4. The corporation has authorized the changes hereinbefore set forth by
resolution of its Board of Directors.

Signed on May 16, 2003

                                     /s/ Robin Smith Hoke
                                     -------------------------------------------
                                     Name: Robin Smith Hoke
                                     Title: Vice President