Comparison of Simultaneous Dual-Isotope Multipinhole SPECT with Rotational SPECT in a Group of Patients with Coronary Artery Disease

¹ Western Cardiology Associates, Westminster, Colorado

^* To whom correspondence should be addressed. E-mail: dlkirch{at}comcast.net.

	Abstract

A triple-detector, multipinhole SPECT system was optimally configured to perform simultaneous ²⁰¹Tl (stress)/^99mTc (rest) myocardial perfusion imaging (MPI) using a protocol that permitted direct diagnostic comparison of this multipinhole SPECT system with conventional rotational SPECT. Methods: Both the rotational and the multipinhole SPECT systems used the same model -detectors. The 2 systems were applied in tandem to study 26 patients with documented coronary status. Visual image evaluation of the MPI together with quantitative analysis using circumferential profile curves (CPC) were used for interpretation of stress/rest myocardial flow differences. A dual-peak attenuation compensation (DPAC) technique was applied to the stress ²⁰¹Tl multipinhole SPECT images by weighted combination of the images from the upper and lower peaks. Results: Detection of myocardial infarction by location and extent correlated closely, and correlation of differential flow changes between stress and rest indicated similar accuracy in terms of location and extent of myocardial blood flow differences as well. In addition, the application of DPAC clarified the multipinhole stress ²⁰¹Tl images through reduced background and increased statistics and also improved the relative superposition of the normalized CPC, especially for the inferior and more basal reconstructed regions. Conclusion: The prototype 3-detector multipinhole SPECT system achieved diagnostic results comparable to those for rotational SPECT and required only a single image-acquisition session to generate stress/rest MPI and 16-segment poststress gated studies. This reduction in acquisition time significantly improves productivity without compromising diagnostic accuracy. In addition, DPAC is a useful adjunct to the multipinhole SPECT modality because it improves both the visual clarity of the stress images and the stress/rest quantitative comparability.

Key Words: myocardial perfusion imaging, SPECT, multipinhole collimation, attenuation correction, circumferential profile curves