Exhibit 99.4

NOTICE OF GUARANTEED DELIVERY

FOR

TENDER OF SHARES OF COMMON STOCK

OF

ETRIALS WORLDWIDE, INC.

TO

MERGE ACQUISITION CORP.,

a wholly owned subsidiary

OF

MERGE HEALTHCARE INCORPORATED

(Not to Be Used for Signature Guarantees)

THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 12:00 MIDNIGHT, NEW YORK CITY TIME, AT THE END OF JULY 14, 2009, UNLESS EXTENDED.

This Notice of Guaranteed Delivery, or one substantially in the form hereof, must be used to accept the Offer (as defined below) if (i) certificates representing shares of Common Stock, par value $0.0001 per share, of etrials Worldwide, Inc., a Delaware corporation (“etrials”) (the “Common Stock” and each share of Common Stock being hereinafter referred to as a “Share”), are not immediately available, (ii) time will not permit all required documents to reach American Stock Transfer & Trust Company (the "Depositary") prior to the Expiration Date (as defined in the Preliminary Prospectus/Offer to Exchange, dated June 16, 2009 (the “Preliminary Prospectus”)) or (iii) the procedures for book-entry transfer cannot be completed on a timely basis. This Notice of Guaranteed Delivery may be delivered by hand or mail or transmitted by telegram or facsimile to the Depositary. See the section of the Preliminary Prospectus entitled “The Offer - Procedure for Tendering.”

The Depositary for the Offer is:

American Stock Transfer & Trust Company

By Mail:	By Overnight Courier:	By Hand:
59 Maiden Lane	6201 15th Avenue, 3rd Floor	59 Maiden Lane, Plaza Level
New York, NY 10038	Brooklyn, NY 11219	New York, NY 10038
	Attn: Reorg Department

By Facsimile Transmission:	Confirm Facsimile Transmission
(For Eligible Institutions Only)	By Telephone Only:
718-234-5001	212-936-5100

DELIVERY OF THIS NOTICE OF GUARANTEED DELIVERY TO AN ADDRESS OTHER THAN AS SET FORTH ABOVE, OR TRANSMISSION OF INSTRUCTIONS VIA FACSIMILE TRANSMISSION OTHER THAN AS SET FORTH ABOVE, WILL NOT CONSTITUTE A VALID DELIVERY.

THIS FORM IS NOT TO BE USED TO GUARANTEE SIGNATURES. IF A SIGNATURE ON A LETTER OF TRANSMITTAL IS REQUIRED TO BE GUARANTEED BY AN "ELIGIBLE INSTITUTION" UNDER THE INSTRUCTIONS THERETO, SUCH SIGNATURE GUARANTEE MUST APPEAR IN THE APPLICABLE SPACE PROVIDED IN THE SIGNATURE BOX ON THE LETTER OF TRANSMITTAL.

Ladies and Gentlemen:

The undersigned hereby tenders to Merge Acquisition Corp., a Delaware corporation and a wholly owned subsidiary of Merge Healthcare Incorporated, a Delaware corporation, upon the terms and subject to the conditions set forth in the Preliminary Prospectus, and the related Letter of Transmittal (which, each as amended or supplemented from time to time, together constitute the “Offer”), receipt of each of which is hereby acknowledged, the number of Shares specified below pursuant to the guaranteed delivery procedures described in the Section captioned “The Offer – Guaranteed Delivery” included in the Preliminary Prospectus.

Number of Shares Tendered:

Certificate Nos. (if available):

Names(s) of Record Holder(s):

(Please Print)

Address(es)

(Include a Zip Code)

If Shares will be tendered

by book-entry transfer:

Name of Tendering Institutions:

Account No.:

Signature(s):

Dated: , 2009

THE GUARANTEE SET FORTH BELOW MUST BE COMPLETED

GUARANTEE

(NOT TO BE USED FOR SIGNATURE GUARANTEE)

The undersigned, a firm that is a bank, broker, dealer, credit union, savings association or other entity that is a member in good standing of the Security Transfer Agents Medallion Program, the New York Stock Exchange Medallion Signature Guarantee Program or the Stock Exchange Medallion Program hereby (a) represents that the tender of Shares effected hereby complies with Rule 14e-4 under the Securities Exchange Act of 1934, as amended, and (b) guarantees delivery to the Depositary, at one of its addresses set forth above, of certificates representing the Shares tendered hereby in proper form for transfer, or confirmation of book-entry transfer of such Shares into the Depositary's account at The Depository Trust Company, in each case with delivery of a properly completed and duly executed Letter of Transmittal (or facsimile thereof) with any required signature guarantees, or an agent's message (as defined in the section of the Preliminary Prospectus/Offer to Exchange entitled “The Offer - Procedure for Tendering”), and any other documents required by the Letter of Transmittal, within three New York Stock Exchange trading days after the date of execution of this Notice of Guaranteed Delivery.

The Eligible Institution that completes this form must communicate the guarantee to the Depositary and must deliver the Letter of Transmittal and certificates for Shares to the Depositary within the time period shown herein. Failure to do so could result in a financial loss to such Eligible Institution.

Name of Firm:
	(Authorized Signature)

Address:
	(Include Zip Code)

Area Code and Telephone Number:

Name:
	(Please Type or Print)

Title:

Dated: , 2009

NOTE:  DO NOT SEND CERTIFICATES FOR SHARES WITH THIS NOTICE.  CERTIFICATES SHOULD BE SENT WITH YOUR LETTER OF TRANSMITTAL