Inclusion Criteria:

1. Able to provide written informed consent
2. Scheduled for stress echocardiography, SPECT nuclear imaging and/or coronary angiography within the two weeks prior to or following Study Day 1
3. Adequate visualization of all myocardial segments in at least one imaging plane during screening non-contrast echocardiogram

Exclusion Criteria:

1. Women who were pregnant or lactating

2. Known hypersensitivity or known contraindication to

   1. Dipyridamole
   2. Other ultrasound contrast agents
   3. Blood, blood products, albumin, egg, or protein
3. Use of caffeine or xanthine containing products within the 24 hours prior to PB127 MPE
4. Frequent (> 60/hour) or symptomatic ventricular ectopics at baseline
5. Atrial fibrillation
6. Permanent pacemaker or defibrillator

7. History of:

   1. Complex ventricular arrhythmia
   2. Chronic hepatitis

   3. Liver disease characterized by one or more of the following:

      • current jaundice
      • elevated bilirubin > upper limit of normal
      • currently elevated hepatic enzymes > 2X upper limit of normal
      • current or previous hepatic viral infection
   4. Chronic obstructive pulmonary disease (COPD) that, in the opinion of the Investigator, was significant enough to contraindicate dipyridamole
   5. Bronchospastic airway disease that, in the opinion of the Investigator, was significant enough to contraindicate dipyridamole
   6. Coronary artery bypass graft (CABG) within the 7 days prior to Study Day 1
   7. Heart transplant
   8. Q wave myocardial infarction within the 7 days prior to Study Day 1
   9. Cardiac intervention or surgery within the 7 days prior to Study Day 1
8. Hypertension (systolic blood pressure [SBP] >200 mmHg and diastolic blood pressure [DBP] >110 mmHg)
9. Hypotension (SBP <90 mmHg) documented within the 24 hours prior to Study Day 1

10. Significant valvular disease

    1. Severe aortic stenosis (>100 mmHg peak transvalvar gradient or <0.6 cm2 estimated valve area)
    2. Severe mitral regurgitation (usual clinical criteria plus or minus any of the following: proximal isovelocity surface area [PISA] >1 cm2, forward transmitral gradient of >2 m/sec, unexplained systolic flow reversal or blunting in the pulmonary veins)
    3. Severe mitral stenosis (<1.0 cm2 estimated valve area)
11. Congestive heart failure (New York Heart Association [NYHA] Class IV); NYHA classes are defined in Appendix D of the protocol (see Appendix 16.1.1)
12. Pulmonary edema within the 7 days prior to Study Day 1
13. Resting oxygen saturation of < 90%
14. Pulmonary hypertension characterized by estimated pulmonary artery systolic pressure of >50 mmHg by echo or catheter criteria on Study Day 1
15. Unstable angina, Canadian Cardiovascular Society (CCS) Class IV severity, with ongoing symptoms and/or ongoing infusion of intravenous nitroglycerin; CCS grading criteria are provided in Appendix E of the protocol (see Appendix 16.1.1)
16. Second degree heart block or greater
17. Use of intravenous or intracoronary contrast agent within the 24 hours prior to Study Day 1
18. Medical conditions or other circumstances that would significantly decrease the chances of obtaining reliable data or achieving the study objectives, ie, drug dependence, psychiatric disorder, dementia, or other reasons for expected poor compliance with the Investigator's instructions; medical conditions, associated illness, or extenuating circumstances that made it unlikely that a patient can complete the clinical trial or follow-up evaluations