Increased sensitivity through use of overlapping 180/spl deg/ orbits in clinical myocardial perfusion imaging

Clinical cardiac imaging is hindered by noise due to limited activity and imaging time. Use of 90/spl deg/ dual detector systems with 90/spl deg/ gantry rotation may provide the best sensitivity/resolution for cardiac imaging, but this option is not available to those using a triple-detector system with detectors at 120/spl deg/ intervals. This study utilizes a cardiac/chest phantom to compare several triple-detector orbits, with assessment of sensitivity and resolution. A 180/spl deg/ rotation with reconstruction of two of the three heads was evaluated, resulting in overlapping 180/spl deg/ orbits; use of a starting angle of 165/spl deg/ for the first head placed the overlapping portion of the orbits over the LAO myocardial region, where camera-cardiac distance is most favorable. Use of this overlapping orbit yielded resolution equivalent to a conventional (single-head) 180/spl deg/ rotation. Sensitivity was 90% of that of a 90/spl deg/ dual-detector system, and 20% better than the common practice of using a 120/spl deg/ orbit with reconstruction of 1 and 1/2 heads to achieve a 180/spl deg/ orbit. Use of 36O/spl deg/ acquisition with reconstruction of all three heads provided the greatest sensitivity, though at some loss in image quality. Thus, far those centers performing cardiac imaging using a triple detector system, using overlapping 180/spl deg/ orbits is the preferred acquisition choice.<
>