SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* WEISEL THOMAS PARTNERS GROUP LLC/CA (Last) (First) (Middle) ONE MONTGOMERY STREET SUITE 3700 (Street) SAN FRANCISCO CA 94104 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol ACUSPHERE INC [ ACUS ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 03/15/2005
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	03/15/2005		S		7,000(1)	D	$5.5	2,227,098	I(2)	See Footnote 2(2)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

1. Name and Address of Reporting Person* WEISEL THOMAS PARTNERS GROUP LLC/CA (Last) (First) (Middle) ONE MONTGOMERY STREET SUITE 3700 (Street) SAN FRANCISCO CA 94104 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* WEISEL THOMAS CAPITAL PARTNERS LP (Last) (First) (Middle) 390 PARK AVENUE 17TH FLOOR (Street) NEW YORK NY 10022 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* TWP CEO FOUNDERS CIRCLE QP LP (Last) (First) (Middle) 390 PARK AVENUE 17TH FLOOR (Street) NEW YORK NY 10022 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* WEISEL THOMAS CAPITAL PARTNERS DUTCH LP (Last) (First) (Middle) 390 PARK AVENUE 17TH FLOOR (Street) NEW YORK NY 10022 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* WEISEL THOMAS CAPITAL PARTNERS DUTCH II LP (Last) (First) (Middle) 390 PARK AVENUE 17TH FLOOR (Street) NEW YORK NY 10022 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* TWP 2000 CO INVESTMENT FUND LP (Last) (First) (Middle) ONE MONTGOMERY STREET SUITE 3700 (Street) SAN FRANCISCO CA 94104 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* TWP CEO FOUNDERS CIRCLE AI LP (Last) (First) (Middle) 390 PARK AVENUE 17TH FLOOR (Street) NEW YORK NY 10022 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* WEISEL THOMAS CAPITAL PARTNERS EMPLOYEE FUND LP (Last) (First) (Middle) 390 PARK AVENUE 17TH FLOOR (Street) NEW YORK NY 10022 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* TAILWIND CAPITAL PARTNERS LLC (Last) (First) (Middle) 390 PARK AVENUE 17TH FLOOR (Street) NEW YORK NY 10022 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

Explanation of Responses:

1. The amount reported in Table 1, Column 4 includes 6,002 shares which were disposed of by Thomas Weisel Capital Partners, L.P., 507 shares which were disposed of by TWP CEO Founders' Circle (QP), L.P., 139 shares which were disposed of by TWP CEO Founders' Circle (AI), L.P., 140 shares which were disposed of by Thomas Weisel Capital Partners (Dutch), L.P., 140 shares which were disposed of by Thomas Weisel Capital Partners (Dutch II), L.P., 44 shares which were disposed of by Thomas Weisel Capital Partners Employee Fund, L.P. and 28 shares which were disposed of by TWP 2000 Co-Investment Fund, L.P.

2. Thomas Weisel Partners Group LLC is the managing member of an entity that is (i) the managing member of Tailwind Capital Partners LLC and (ii) the general partner of TWP 2000 Co-Investment Fund, L.P., and thus may be deemed to beneficially own the shares beneficially owned by these entities. Tailwind Capital Partners LLC is (i) the general partner of Thomas Weisel Capital Partners, L.P., TWP CEO Founders' Circle (AI), L.P., TWP CEO Founders' Circle (QP), L.P. and Thomas Weisel Capital Partners Employee Fund, L.P. and (ii) the managing member of the general partner of Thomas Weisel Capital Partners (Dutch), L.P. and Thomas Weisel Capital Partners (Dutch II), L.P., and thus may be deemed to beneficially own the shares held by these entities. The reporting persons disclaim beneficial ownership of such securities except to the extent of their pecuniary interest therein.

	See signatures included in Exhibit 99.1	03/17/2005
	** Signature of Reporting Person	Date
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