<PAGE>
                                                                   Exhibit 10.33


                       [ACUSPHERE, INC. LETTERHEAD]                    ACUSPHERE


      THIS CONSULTING AGREEMENT (the "Agreement"), made as of the 21th Day of
May, 1999, is entered into by and between Acusphere, Inc., a Delaware
corporation with its principal place of business at 38 Sidney Street, Cambridge,
Massachusetts 02139 (the "Company"), and William Ramage, Ph.D., P.O. Box 676042,
Rancho Santa Fe, California 92067-6042 (the "Consultant").

                                INTRODUCTION

      The Company desires to retain the services of the Consultant and the
Consultant desires to perform certain services for the Company. In consideration
of the mutual convenants and promises contained herein and other good and
valuable consideration, the receipt and sufficiency of which is hereby
acknowledged by the parties hereto, the parties agree as follows:

1. Services. The Consultant agrees to perform such consulting, advisory and
related services to and for the Company as may be reasonably requested from time
to time by the Company, including, but not limited to, the services specified on
Schedule A to this Agreement.

2. Term. This Agreement shall commence on May 21, 1999, hereof and shall
continue until May 21, 2000 (such period, as it may be extended, being referred
to as the "Consultation Period"), unless sooner terminated in accordance with
the provisions of Section 4.

3. Compensation.

      3.1 Consulting Fees: The Company shall pay to the Consultant consulting
fees of $1,500 per eight (8) hour day worked and invoiced within 30 days after
receipt of a monthly statement. This fee is inclusive of time spent traveling to
and from the Study site(s) or Meeting locations.

      3.2 Reimbursement of Expenses. The Company shall reimburse the Consultant
for all reasonable and necessary expenses incurred or paid by the Consultant in
connection with, or related to, the performance of his services under this
Agreement. The Consultant shall submit to the Company itemized monthly
statements, in a form satisfactory to the Company, of such expenses incurred in
the previous month. The Company shall pay to the Consultant amounts shown on
each such statement within 30 days after receipt thereof. Notwithstanding the
foregoing, the Consultant shall not incur total expenses in excess of $1,000 per
month without the prior written approval of the Company.


                                      -1-
<PAGE>
                                                                       ACUSPHERE


      3.3 Benefits. The Consultant shall not be entitled to any benefits,
coverages or privileges, including, without limitation, social security,
unemployment, medical or pension payments, made available to employees of the
Company.

4. Termination. Either party may terminate the Consultant Period upon 30 days'
prior written notice to the other party. In the event of such termination, the
Consultant shall be entitled to payment for services performed and expenses paid
or incurred prior to the effective date of termination, subject to the
limitation on reimbursement of expenses set forth in Section 3.2. Such payments
shall constitute full settlement of any and all claims of the Consultant of
every description against the Company. Notwithstanding the foregoing, the
Company may terminate the Consultation Period, effective immediately upon
receipt of written notice, if the Consultant breaches or threatens to breach any
provision of Section 6.

5. Cooperation. The Consultant shall use his best efforts in the performance of
his obligations under this Agreement. The Company shall provide such access to
its information and property as may be reasonably required in order to permit
the consultant to perform his obligations hereunder. The Consultant shall
cooperate with the Company's personnel, shall not interfere with the conduct of
the Company's business and shall observe all rules, regulations and security
requirements of the Company concerning the safety of persons and property.

6.    Inventions and Proprietary Information.

      6.1   Inventions.

            (a) All Inventions, discoveries, computer programs, data,
technology, designs, innovations and improvements (whether or not patentable and
whether or not copyrightable) ("Inventions") related to the business of the
Company which are made, conceived, reduced to practice, created, written,
designed or developed by the Consultant, solely or jointly with others and
whether during normal business hours or otherwise, during the Consultation
Period or thereafter if resulting or directly derived from Proprietary
Information (as defined below), shall be the sole property of the Company. The
Consultant hereby assigns to the Company all Inventions and any and all related
patents, copyrights, trademarks, trade names, and other industrial and
intellectual property rights and applications therefor, in the United States and
elsewhere and appoints any officer of the Company as his duly authorized
attorney to execute, file, prosecute and protect the same before any government
agency, court or authority. Upon the request of the Company and at the Company's
expense, the Consultant shall execute such


                                      -2-
<PAGE>
                                                                       ACUSPHERE



further assignments, documents and other instruments as may be necessary or
desirable to fully and completely assign all Inventions to the Company and to
assist the Company in applying for, obtaining and enforcing patents or
copyrights or other rights in the United States and in any foreign country with
respect to any Invention.

(b) The Consultant shall promptly disclose to the Company all Inventions and
will maintain adequate and current written records (in the form of notes,
sketches, drawings and as may be specified by the Company) to document the
conception and/or first actual reduction to practice of any Invention. Such
written records shall be available to and remain the sole property of the
Company at all times.

      6.2   Proprietary Information.

            (a) The Consultant acknowledges that his relationship with the
Company is one of high trust and confidence and that in the course of his
service to the Company he will have access to and contact with Proprietary
Information. The Consultant agrees that he will not, during the Consultation
Period or at any time thereafter, disclose to others, or use for his benefit or
the benefit of others, any Proprietary Information or Invention.

            (b) For purposes of this Agreement, Proprietary Information shall
mean, by way of illustration and not limitation, all information (whether or not
patentable and whether or not copyrightable) owned, possessed or used by the
Company, including, without limitation, and Invention, formula, vendor
information, customer information, apparatus, equipment, trade secret, process,
research, report, technical data, know-how, computer program, software, software
documentation, hardware design, technology, marketing or business plan,
forecast, unpublished financial statement, budget, license, price, cost and
employee list that is communicated to learned of, developed or otherwise
acquired by the Consultant in the course of his service as a consultant to the
Company.

            (c) The Consultant's obligations under this Section 6.2 shall not
apply to any information that (i) is or becomes known to the general public
under circumstances involving no breach by the Consultant or others of the terms
of this Section 6.2 (ii) is generally disclosed to third parties by the Company
without restriction on such third parties, or (iii) is approved for release by
written authorization of the Board of Directors of the Company.


                                      -3-
<PAGE>
                                                                       ACUSPHERE


            (d) Upon termination of this Agreement or at any other time upon
request by the Company, the consultant shall promptly deliver to the Company all
records, files, memoranda, notes, designs, data, reports, price lists, customer
lists, drawings, plans, computer programs, software, software documentation,
sketches, laboratory and research notebooks and other documents (and all copies
or reproductions of such materials) relating to the business of the Company.

            (e) The Consultant represent his retention as a consultant with the
Company and his performance under this Agreement does not, and shall not, breach
any agreement that obligates him to keep in confidence any trade secrets or
confidential or proprietary information of this or of any other party or to
refrain from competing, directly or indirectly, with the business of any other
party. The Consultant shall not disclose to the Company any trade secrets or
confidential or proprietary information of any other party.

            (f) The Consultant acknowledges that the Company from time to time
may have agreements with other persons or with the United States Government, or
agencies thereof, that impose obligations or restrictions on the Company
regarding inventions made during the course of work under such agreements or
regarding the confidential nature of such work. The Consultant agrees to be
bound by all such obligations and restrictions that are known to him and to take
all action necessary to discharge the obligations of the Company under such
agreement.

      6.3 Remedies. The Consultant acknowledges that any breach of the
provisions of this Section 6 shall result in serious and irreparable injury to
the Company for which the Company cannot be adequately compensated by monetary
damages alone. The Consultant agrees, therefore, that, in addition to any other
remedy it may have, the Company shall be entitled to enforce the specific
performance of this Agreement by the Consultant and to seek both temporary and
permanent injunctive relief (to the extent permitted by law) without the
necessity of proving actual damages.

7. Independent Contractor Status. The Consultant shall perform all services
under this Agreement as an "independent contractor" and not as an employee or
agent of the Company. The Consultant is not authorized to assume or create any
obligation or responsibility, express or implied, on behalf of, or in the name,
of the Company or to bind the Company in any manner. Consultant acknowledges
that as an independent contractor he is not entitled to participate in or
receive any benefit or right offered to employees of the Company under any
employee benefit plan, including without limitation, medical and health
insurance. Consultant acknowledges that the Company will not withhold taxes on
any amounts paid to him


                                      -4-
<PAGE>
                                                                       ACUSPHERE


hereunder and that Consultant is responsible for all tax withholding, social
security, unemployment insurance and other similar payments.

8. Notices. All notices required or permitted under this Agreement shall be in
writing and shall be deemed effective upon personal delivery or upon deposit in
the United States Post Office, by registered or certified mail, postage prepaid,
addressed to the other party at the address shown above, or at such other
address or addresses as either party shall designate to the other in accordance
this Section 8.

9.    Pronouns.  Whenever the context may require, any pronouns used in
this Agreement shall include the corresponding masculine, feminine or
neuter forms, and the singular forms of nouns and pronouns shall include
the plural, and vice versa.

10.   Entire Agreement.  This Agreement constitutes the entire agreement
between the parties and supersedes all prior agreement and understandings,
whether written or oral, relating to the subject matter of this Agreement.

11.   Amendment.  This Agreement may be amended or modified only by
written instrument executed by both the Company and the Consultant.

12.   Governing Law.  This Agreement shall be construed, interpreted and
enforced in accordance with the laws of the Commonwealth of Massachusetts.

13. Successors and Assigns. This Agreement shall be binding upon, and inure to
the benefit of, the Company's successors and assigns, including any corporation
with which, or into which, the Company may be merged or which may succeed to its
assets or business, provided, however, that the obligations of the Consultant
are personal and shall not be assigned by him.

14.   Survival.  The covenants, agreement, representations and warranties
contained in or made pursuant to this Agreement (including without
limitation Section 6 hereof) shall survive termination of Consultant's
services as provided herein.

15.   Miscellaneous.

      15.1 No delay or omission by the Company in exercising any right under
this Agreement shall operate as a waiver of that or any right. A waiver or
consent given by the Company on any one occasion shall be effective only in that
instance and shall not be construed as a bar or waiver of any right on any other
occasion.


                                      -5-
<PAGE>
                                                                       ACUSPHERE


      15.2 The captions of the sections of this Agreement are for convenience of
reference only and in no way define, limit or affect the scope or substance of
any section of this Agreement.

      15.3 In the event that any provision of this Agreement shall be invalid,
illegal or otherwise unenforceable, the validity, legality and enforceability of
the remaining provisions shall in no way be affected or impaired thereby.

                [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]


                                      -6-
<PAGE>
                                                                       ACUSPHERE


      IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of
the day and year set forth above.



                                    ACUSPHERE, INC.

                                    By: /s/ Richard Walovitch
                                        ----------------------------------------
                                    Title: VP Clinical Research



                                    WILLIAM RAMAGE
                                    --------------------------------------------
                                    /s/ William Ramage


                                      -7-
<PAGE>
                                                                       ACUSPHERE


                                 SCHEDULE A


-     Consulting and travel as necessary to discuss ultrasound contrast agent
      marketing and clinical application.


                                      -8-
<PAGE>
                       [ACUSPHERE, INC. LETTERHEAD]                    ACUSPHERE


                  AMENDMENT NO. 1 TO CONSULTING AGREEMENT

      This Amendment No. 1 dated as of December 7, 1999 (this "Amendment
No. 1") amends that certain Consulting Agreement, dated as of May 21, 1999
(the "Consulting Agreement") by and among Acusphere, Inc., a Delaware
corporation (the "Company") and William Ramage (the "Consultant").

1.    Amendment of the Consulting Agreement.

      1.01. Section 1 of the Consulting Agreement shall be deleted in its
entirety and replaced with the following:

      "1(a). Services.  The Consultant agrees to perform such consulting,
      advisory and related services to and for the Company as may be reasonably
      requested from time to time by the Company, including, but not limited to,
      the services specified on Schedule A to this Agreement.

      1(b). Non-Competition. During the Consultation Period and for ninety days
      thereafter (the "Non-Compete Period"), the Consultant agrees that he shall
      not, directly or indirectly, alone or as a partner, officer, director,
      employee, agent, consultant or stockholder of any entity, pursue, solicit
      or conduct any business opportunity reasonably related to any ultrasound
      contrast agent ("Restricted Actions"). In the event the Company fails to
      engage Consultant for an average of three and one-half eight-hour work
      days over any seven day period, excluding mutually agreed upon vacation
      time or other absence, Consultant may notify the Company of such fact (the
      date on which the Company receives such notice being referred to herein as
      the "Notice Date"). If such failure by the Company to so engage Consultant
      continues for two weeks after the Notice Date, the Non-Compete Period
      shall expire ninety days after the Notice Date. Notwithstanding the
      foregoing, Consultant may, during the ninety day period following the
      termination of this Agreement or at any time after the expiration of the
      Non-Compete Period, interview with actual or potential competitors of the
      Company, provided, however, that Consultant does not engage in any
      Restricted Actions during the Non-Compete Period."

2.    Miscellaneous.

      2.01. Effect.  Except as amended hereby, the Consultant Agreement, as
amended, shall remain in full force and effect.

      2.02. Defined Terms.  All capitalized terms used but not specifically
defined herein shall have the same meanings given such terms in the Consultant
Agreement unless the context clearly indicates or dictates a contrary meaning.
<PAGE>
                                      -2-


                       [ACUSHERE, INC. LETTERHEAD]                     ACUSPHERE


      2.03. Governing Law.  This Amendment No. 1 shall be governed by, and
construed and enforced in accordance with, the internal laws of the
Commonwealth of Massachusetts, without regard to conflicts of laws
principles.

      2.04. Counterparts.  This Amendment No. 1 may be executed in any
number of counterparts, all of which taken together shall constitute one
and the same instrument, and each of the parties hereto may execute this
Amendment No. 1 by signing any of such counterparts.


                [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]
<PAGE>
                                      -3-


                                                                       ACUSPHERE


      IN WITNESS WHEREOF, the parties hereto have executed this Amendment No. 1
as of the date first above written.


                                                ACUSPHERE, INC.

                                                By: /s/ Sherri C. Oberg
                                                    ----------------------------
                                                    Name: Sherri C. Oberg
                                                    Title: President and CEO


                                                /s/ William Ramage
                                                --------------------------------
                                                William Ramage
<PAGE>
                  AMENDMENT NO. 2 TO CONSULTING AGREEMENT

      This Amendment No. 2 dated as of September 15, 2000 (this "Amendment
No. 2") amends that certain Consulting Agreement, dated as of May 21,
1999, as amended by Amendment No. 1 to the Consulting Agreement dated as
of December 1999 (the "Consulting Agreement"), by and among Acusphere,
Inc., a Delaware corporation (the "Company") and William Ramage (the
"Consultant").

1.    Amendment of the Consulting Agreement.

      1.01. Section 2 of the Consulting Agreement shall be deleted in its
      entirety and replaced with the following:

      2. Term. This Agreement shall commence on May 21, 1999, hereof and shall
      continue until November 30, 2003 (such period, as it may be extended,
      being referred to as the "Consultation Period"), unless sooner terminated
      in accordance with the provisions of Section 4."

      1.02 Section 3 of the Consulting Agreement shall be deleted in its
      entirety and replaced with the following:

      3.1. Consulting Fees. The Company agrees to pay the Consultant consulting
      fees of $1,250 per day for the first ten (10) days worked in a calendar
      month. Should the Consultant provide consulting services to the Company in
      excess of ten days in any given calendar month, the Company shall pay the
      Consultant $1,000 per day for each additional day worked by the
      Consultant. This fee is inclusive of time spent traveling to and from the
      Study site(s) or Meeting locations.

      3.2. Stock Options. The Company and the Consultant shall execute an option
      agreement, in a form substantially similar to the one attached hereto as
      Schedule B, to purchase up to 30,000 shares of the Company's Common Stock,
      $.01 par value per share (the "Common Stock").

      3.3. Reimbursement of Expenses. The Company shall reimburse the Consultant
      for all reasonable and necessary expenses incurred or paid by the
      Consultant in connection with, or related to, the performance of his
      services under this Agreement. The Consultant shall submit to the Company
      itemized monthly statements, in a form satisfactory to the Company, of
      such expenses incurred in the previous month. The Company shall pay to the
      Consultant amounts shown on each such statement within 30 days after
      receipt thereof. Notwithstanding the foregoing, the Consultant shall not
      incur total expenses in excess of $1,000 per month without the prior
      written approval of the Company.
<PAGE>
                                      -2-


      3.4.  Benefits.  The Consultant shall not be entitled to any
      benefits, coverages or privileges, including, without limitation,
      social security, unemployment, medical or pension payments, made
      available to employees of the Company."

2.    Miscellaneous.

      2.01. Effect.  Except as amended hereby, the Consultant Agreement,
as amended, shall remain in full force and effect.

      2.02. Defined Terms.  All capitalized terms used but not
specifically defined herein shall have the same meanings given such terms
in the Consultant Agreement unless the context clearly indicates or
dictates a contrary meaning.

      2.03. Governing Law.  This Amendment No. 2 shall be governed by, and
construed and enforced in accordance with, the internal laws of the
Commonwealth of Massachusetts, without regard to conflicts of laws
principles.

      2.04. Counterparts.  This Amendment No. 2 may be executed in any
number of counterparts, all of which taken together shall constitute one
and the same instrument, and each of the parties hereto may execute this
Amendment No. 2 by signing any of such counterparts.


                [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]
<PAGE>
                                      -3-


      IN WITNESS WHEREOF, the parties hereto have executed this Amendment No. 2
as of the date first above written.


                                                ACUSPHERE, INC.

                                                By: /s/ Sherri Oberg
                                                    ----------------------------
                                                    Name: Sherri Oberg
                                                    Title: President and C.E.O.


                                                /s/ William Ramage
                                                --------------------------------
                                                William Ramage
<PAGE>
                                      -4-


                                 SCHEDULE B

                    Non-Qualified Stock Option Agreement
<PAGE>
                              ACUSPHERE, INC.

                    Non-Qualified Stock Option Agreement


      Acusphere, Inc., a Delaware corporation (the "Corporation"), hereby grants
this 27th day of September, 2000 to Bill Ramage (the "Optionee"), an option to
purchase a maximum of 30,000 shares (the "Option Shares") of its Common Stock,
$.01 par value, at the price of $0.95 per share, on the following terms and
conditions:

      1.    Grant Under 1994 Stock Plan. This option is granted pursuant to and
is governed by the Corporation's 1994 Stock Plan (the "Plan") and, unless the
context otherwise requires, terms used herein shall have the same meaning as in
the Plan. Determinations made in connection with this option pursuant to the
Plan shall be governed by the Plan as it exists on this date.

      2.    Grant as Non-Qualified Stock Option; Other Options. This option is
intended to qualify as a non-qualified option (rather than an incentive stock
option under Section 422 of the Internal Revenue Code of 1986, as amended (the
"Code")) and the Board of Directors intends to take appropriate action, if
necessary, to achieve this result. This option is in addition to any other
options heretofore or hereafter granted to the Optionee by the Corporation, but
a duplicate original of this instrument shall not affect the grant of another
option.

      3.    Extent of Option if Business Relationship Continues. If the Optionee
has continued to serve the Corporation or any Related Corporation in the
capacity of an employee, officer, director or consultant (such service is
described herein as maintaining or being involved in a "Business Relationship"
with the Corporation), the Optionee may exercise this option for the total
number of Option Shares set forth opposite the applicable date as follows:

<TABLE>
<CAPTION>
On September 30, 2000                        845 Option Shares

<S>                                          <C>
On the last day of each of the               An additional 833 Option
following thirty-five (35) months            Shares.
commencing on October 31, 2000
until and through August 31, 2003.
</TABLE>


      All of the foregoing rights are subject to Sections 4 and 5, as
appropriate, if the Optionee ceases to maintain a Business Relationship with the
Corporation or dies, becomes disabled or undergoes dissolution while involved in
a Business Relationship with the Corporation.
<PAGE>
                                      -2-


      4. Termination of Business Relationship. If the Optionee ceases to
maintain a Business Relationship with the Corporation, other than by reason of
death or disability as defined in Section 5, no further installments of this
option shall become exercisable and this option shall terminate after the
passage of sixty (60) days from the date the Business Relationship ceases, but
in no event later than the scheduled expiration date. In such a case, the
Optionee's only rights hereunder shall be those which are properly exercised
before the termination of this option.

      5. Death; Disability; Dissolution. If the Optionee is a natural person who
dies while involved in a Business Relationship with the Corporation, this option
may be exercised, to the extent otherwise exercisable on the date of his death,
by his estate, personal representative or beneficiary to whom this option has
been assigned pursuant to Section 10, at any time within 180 days after the date
of death, but not later than the scheduled expiration date. If the Optionee is a
natural person whose Business Relationship with the Corporation is terminated by
reason of his disability (as defined in the Plan), this option may be exercised,
to the extent otherwise exercisable on the date the Business Relationship was
terminated, at any time within 180 days after the date of such termination, but
not later than the scheduled expiration date. At the expiration of such 180-day
period or the scheduled expiration date, whichever is the earlier, this option
shall terminate and the only rights hereunder shall be those as to which the
option was properly exercised before such termination. If the Optionee is a
corporation, partnership, trust or other entity that is dissolved, liquidated,
becomes subject to a voluntary or involuntary bankruptcy proceeding, has a
receiver appointed for all or a substantial portion of its property or enters
into a merger or acquisition with respect to which such optionee is not the
surviving entity at the time when such entity is involved in a Business
Relationship with the Corporation, this Option shall immediately terminate as of
the date of such event, and the only rights hereunder shall be those as to which
this option was properly exercised before such dissolution or other event.

      6. Partial Exercise. Exercise of this option up to the extent above stated
may be made in part at any time and from time to time within the above limits,
except that this option may not be exercised for a fraction of a share unless
such exercise is with respect to the final installment of stock subject to this
option and a fractional share (or cash in lieu thereof) must be issued to permit
the Optionee to exercise completely such final installment. Any fractional share
with respect to which an installment of this option cannot be exercised because
of the limitation contained in the preceding sentence shall remain subject to
this option and shall be available for later purchase by the Optionee in
accordance with the terms hereof.

      7.    Payment of Price.  The option price is payable in United
States dollars and may be paid:
<PAGE>
                                      -3-


            (a)   in cash or by check, or any combination of the
      foregoing, equal in amount to the option price; or

            (b) in the discretion of the Corporation's Board of Directors, in
      cash, by check, by delivery of shares of the Corporation's Common Stock
      having a fair market value (as determined by the Board of Directors) equal
      as of the date of exercise to the option price, or by any combination of
      the foregoing, equal in amount to the option price.

            Notwithstanding the foregoing, the Employee may not pay any part of
the exercise price hereof by transferring Common Stock to the Corporation if
such Common Stock is both subject to a substantial risk of forfeiture and not
transferable within the meaning of Section 83 of the Code.

      8. Method of Exercising Option. Subject to the terms and conditions of
this Agreement, this option may be exercised by written notice to the
Corporation, at the principal executive office of the Corporation, or to such
transfer agent as the Corporation shall designate. Such notice shall state the
election to exercise this option and the number of shares for which it is being
exercised and shall be signed by the person or persons so exercising this
option. Such notice shall be accompanied by payment of the full purchase price
of such shares, and the Corporation shall deliver a certificate or certificates
representing such shares as soon as practicable after the notice shall be
received. Such certificate or certificates shall be registered in the name of
the person or persons so exercising this option (or, if this option shall be
exercised by the Optionee and if the Optionee shall so request in the notice
exercising this option, shall be registered in the name of the Optionee and
another person jointly, with right of survivorship) and shall be delivered as
provided above to or upon the written order of the person or persons exercising
this option. In the event this option shall be exercised, pursuant to Section 5
hereof, by any person or persons other than the Optionee, such notice shall be
accompanied by appropriate proof of the right of such person or persons to
exercise this option. All shares that shall be purchased upon the exercise of
this option as provided herein shall be fully paid and non-assessable.

      9. Restrictions on Transfer. Option Shares may not be transferred without
the Corporation's written consent, except by will, by the laws of descent and
distribution, or in accordance with the provisions of Section 16, if applicable.
Option Shares will be of an illiquid nature and will be deemed to be "restricted
securities" for purposes of the Securities Act of 1933, as amended. Accordingly,
such shares must be sold in compliance with the registration requirements of
such Act or an exemption therefrom.

      10.   Option Not Transferable.  This option is not transferable or
assignable.  Only the Optionee can exercise this option.
<PAGE>
                                      -4-


      11.   No Obligation to Exercise Option.  The grant and acceptance of
this option imposes no obligation on the Optionee to exercise it.

      12.   No Obligation to Continue Business Relationship.  The
Corporation and any Related Corporations are not by the Plan or this
option obligated to continue to maintain a business relationship with the
Optionee.

      13. No Rights as Stockholder until Exercise. The Optionee shall have no
rights as a stockholder with respect to the Option Shares until a stock
certificate therefor has been issued to the Optionee and is fully paid for in
accordance with Section 7. Except as is expressly provided in the Plan with
respect to certain changes in the capitalization of the Corporation, no
adjustment shall be made for dividends or similar rights for which the record
date is prior to the date such stock certificate is issued.

      14. Capital Changes and Business Successions. It is the purpose of this
option to encourage the Optionee to work for the best interests of the
Corporation and its stockholders. Since, for example, that might require the
issuance of a stock dividend or a merger with another corporation, the purpose
of this option would not be served if such a stock dividend, merger or similar
occurrence would cause the Optionee's rights hereunder to be diluted or
terminated and thus be contrary to the Optionee's interest. The Plan contains
extensive provisions designed to preserve options at full value in a number of
contingencies. Therefore, provisions in the Plan for adjustment with respect to
stock subject to options and the related provisions with respect to successors
to the business of the Corporation are hereby made applicable hereunder and are
incorporated herein by reference.

      15. Withholding Taxes. If the Corporation or any related corporation in
its discretion determines that it is obligated to withhold any tax in connection
with the exercise of this option, or in connection with the transfer of, or the
lapse of restrictions on, any Common Stock or other property acquired pursuant
to this option, the Optionee hereby agrees that the Corporation or related
corporation may withhold from the Optionee's wages or other remuneration the
appropriate amount of tax. At the discretion of the Corporation or related
corporation, the amount required to be withheld may be withheld in cash from
such wages or other remuneration, or in kind from the Common Stock otherwise
deliverable to the Optionee on exercise of this option. The Optionee further
agrees that, if the Corporation or related corporation does not withhold an
amount from the Optionee's wages or other remuneration sufficient to satisfy the
withholding obligation of the Corporation or related corporation, the Optionee
will reimburse the Corporation or related corporation on demand, in cash, for
the amount underwithheld.

      16.   Corporation's Right of First Refusal.
<PAGE>
                                      -5-


            (a)   Exercise of Right: If the Optionee or the Optionee's legal
representative (the "Transferor") desires to transfer all or any part of the
Option Shares to any person other than the Corporation (an "Offeror"), the
Transferor shall: (i) obtain in writing an irrevocable and unconditional bona
fide offer (the "Offer") for the purchase thereof from the Offeror; and (ii)
give written notice (the "Option Notice") to the Corporation setting forth the
Optionee's desire to transfer such shares, which Option Notice shall be
accompanied by a photocopy of the Offer and shall set forth at least the name
and address of the Offeror and the price and terms of the bona fide offer. Upon
receipt of the Option Notice, the Corporation shall have an assignable option to
purchase any or all of such shares (the "Corporation Option Shares") specified
in the Option Notice, such option to be exercisable by giving, within 30 days
after receipt of the Option Notice, a written counter-notice to the Transferor.
If the Corporation elects to purchase any or all of such Corporation Option
Shares, it shall be obligated to purchase, and the Optionee shall be obligated
to sell to the Corporation, such Corporation Option Shares at the price and
terms indicated in the Offer within 30 days from the date of delivery by the
Corporation of such counter-notice.

            (b)   Sale of Option Shares to Offeror: The Transferor may, for 60
days after the expiration of the 30-day period during which the Corporation may
give the counter-notice, sell, pursuant to the terms of the Offer, any or all of
such Corporation Option Shares not purchased or agreed to be purchased by the
Corporation or its assignee; provided, however, that the Transferor shall not
sell such Corporation Option Shares to the Offeror if the Offeror is a
competitor of the Corporation and the Corporation gives written notice to the
Transferor, within 30 days of its receipt of the Option Notice, stating that the
Transferor shall not sell such Corporation Option Shares to such Offeror; and
provided, further, that prior to the sale of such Corporation Option Shares to
the Offeror, the Offeror shall execute an agreement with the Corporation
pursuant to which the Offeror agrees to be subject to the restrictions set forth
in this Section 16. If any or all of such Corporation Option Shares are not sold
pursuant to an Offer within the time permitted above, the unsold Corporation
Option Shares shall remain subject to the terms of this Section 16.

            (c)   Adjustments for Changes in Capital Structure: If there shall
be any change in the Common Stock of the Corporation through merger,
consolidation, reorganization, recapitalization, stock dividend, stock split,
combination or exchange of shares, or the like, the restrictions contained in
this Section 16 shall apply with equal force to additional and/or substitute
securities, if any, received by the Optionee in exchange for, or by virtue of
his or her ownership of, Corporation Option Shares.

            (d)   Failure to Deliver Corporation Option Shares: If the
Transferor fails or refuses to deliver on a timely basis duly endorsed
certificates representing Corporation Option Shares to be sold to the
Corporation or its assignee pursuant to this Section 16, the Corporation shall
have the right to deposit the purchase price for such Corporation Option Shares
in a special
<PAGE>
                                      -6-


account with any bank or trust company in the Commonwealth of Massachusetts or
State of Delaware, giving notice of such deposit to the Transferor, whereupon
such Corporation Option Shares shall be deemed to have been purchased by the
Corporation. All such monies shall be held by the bank or trust company for the
benefit of the Transferor. All monies deposited with the bank or trust company
remaining unclaimed for two years after the date of deposit shall be repaid by
the bank or trust company to the Corporation on demand, and the Transferor shall
thereafter look only to the Corporation for payment. The Corporation may place a
legend on any stock certificate delivered to the Transferor reflecting the
restrictions on transfer provided in Section 9 hereof and this Section 16.

            (e)   Expiration of Corporation's Right of First Refusal: The first
refusal rights of the Corporation set forth above shall remain in effect until
such time, if ever, as a distribution to the public is made of shares of the
Corporation's Common Stock pursuant to a registration statement filed under the
Securities Act of 1933, as amended (the "Act") or a successor statute, at which
time the first refusal rights of the Corporation set forth herein will
automatically expire.

      17.   Provision of Documentation to Optionee.  By signing this
Agreement the Optionee acknowledges receipt of a copy of this Agreement
and a copy of the Plan.

      18. Market "Stand-Off" Agreement. The Optionee hereby agrees that, during
the period of duration (not to exceed one hundred eighty (180) days) specified
by the Corporation and an underwriter of Common Stock or other securities of the
Corporation, following the effective date of a registration statement of the
Corporation filed under the Act, such Optionee shall not, to the extent
requested by the Corporation and such underwriter, directly or indirectly sell,
offer to sell, contract to sell (including, without limitation, any short sale),
grant any option to purchase or otherwise transfer or dispose of (other than to
donees who agree to be similarly bound) any securities of the Corporation held
by the Optionee at any time during such period except Common Stock included in
such registration; provided however, that (i) such agreement shall be applicable
only with respect to an initial public offering of the Corporation's securities
and (ii) all officers and directors of the Corporation and all other persons
with registration rights enter into similar agreements.

      19.   Miscellaneous.

            (a)   Notices: All notices hereunder shall be in writing and shall
be deemed given when sent by certified or registered mail, postage prepaid,
return receipt requested, to the address set forth below. The addresses for such
notices may be changed from time to time by written notice given in the manner
provided for herein.

            (b)   Entire Agreement; Modification: This Agreement constitutes the
entire agreement between the parties relative to the subject matter hereof,
<PAGE>
                                      -7-


and supersedes all proposals, written or oral, and all other communications
between the parties relating to the subject matter of this Agreement. This
Agreement may be modified, amended or rescinded only by a written agreement
executed by both parties.

            (c)   Severability: The invalidity, illegality or unenforceability
of any provision of this Agreement shall in no way affect the validity, legality
or enforceability of any other provision.

            (d)   Successors and Assigns: This Agreement shall be binding upon
and inure to the benefit of the parties hereto and their respective successors
and assigns, subject to the limitations set forth in Section 10 hereof.

            (e)   Governing Law: This Agreement shall be governed by and
interpreted in accordance with the laws of the state of Delaware without giving
effect to the principles of the conflicts of laws thereof. The preceding choice
of law provision shall apply to all claims, under any theory whatsoever, arising
out of the relationship of the parties contemplated herein.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]
<PAGE>
                                      -8-


      IN WITNESS WHEREOF the Corporation and the Optionee have caused this
instrument to be executed, and the Optionee whose signature appears below
acknowledges receipt of a copy of the Plan and acceptance of an original copy of
this Agreement.

                                    ACUSPHERE, INC.


                                    By: /s/ Sherri C. Oberg
                                        ----------------------------------------

                                    Title: President and CEO
                                           -------------------------------------
                                    Address: 38 Sidney Street
                                             Cambridge, MA 02139

                                    --------------------------------------------
                                    /s/ Bill Ramage
                                    --------------------------------------------
                                    Bill Ramage

                                    Address: PO Box 676042
                                             -----------------------------------
                                             Rancho Santa Fe, CA
                                             -----------------------------------