Power Doppler harmonic imaging: A feasibility study of a new technique for the assessment of myocardial perfusion

Background: The aim of the study was to assess the feasibility of a new technique, power Doppler harmonic imaging (PDHI), for assessing myocardial perfusion through a venous injection of microbubbles, with the use of a new ultrasound contrast agent. Methods and Results: Fifteen patients with known coronary artery disease and a resting perfusion abnormality on Tc-99m sestamibi single-photon emission computed tomography (SPECT) underwent PDHI at rest during intravenous injections of 2 to 3 mL of Sonovue (Bracco SpA, Milan, Italy), a new second-generation ultrasound contrast agent. Myocardial perfusion was determined to be present or absent by use of a 5-segment model by 2 blinded observers for both PDHI and SPECT. Of a total of 75 possible myocardial segments, 7 (9%) were not analyzed because of obvious artifacts on PDHI. SPECT showed perfusion defects in 40 of the remaining 68 segments, whereas PDHI showed 39 defects. There was high concordance between the 2 imaging modalities for the presence (93%) as well as the location (96% for the anteroseptal region, 93% for the inferoposterior region, and 87% for the apical region) of the defects. Conclusions: These preliminary results suggest that PDHI is a feasible technique for the detection of resting myocardial perfusion defects in patients with coronary artery disease after a venous injection of a new second-generation ultrasound contrast agent.