Value of attenuation correction in stress-only myocardial perfusion imaging using CZT-SPECT

Abstract

BackgroundAttenuation correction (AC) improves the diagnostic outcome of stress-only myocardial perfusion imaging (MPI) using conventional SPECT. Our aim was to determine the value of AC using a cadmium zinc telluride-based (CZT)-SPECT camera.Methods and resultsWe retrospectively included 107 consecutive patients who underwent stress-optional rest MPI CZT-SPECT/CT. Next, we created three types of images for each patient; (1) only displaying reconstructed data without the CT-based AC (NC), (2) only displaying AC, and (3) with both NC and AC (NC + AC). Next, two experienced physicians visually interpreted these 321 randomized images as normal, equivocal, or abnormal. Image outcome was compared with all hard events over a mean follow-up time of 47.7 ± 9.8 months. The percentage of images interpreted as normal increased from 45% using the NC images to 72% using AC and to 67% using NC + AC images (P < .001). Hard event hazard ratios for images interpreted as normal were not different between using NC and AC (1.01, P = .99), or NC and NC + AC images (0.97, P = .97).ConclusionsAC lowers the need for additional rest imaging in stress-first MPI using CZT-SPECT, while long-term patient outcome remained identical. Use of AC reduces the need for additional rest imaging, decreasing the mean effective dose by up to 1.2 mSv.

Rationale and design of the REgistry of Fast Myocardial Perfusion Imaging with NExt generation SPECT (REFINE SPECT)

“…Reconstructed images are generated from the list mode data by vendor-recommended iterative reconstruction optimized for each scanner at each participating site. If CT is obtained for attenuation correction, CT images are collected, and attenuation corrected data are included (5). …”

Diagnostic implications of CZT SPECT and impact of CT attenuation correction

“…Diagnostic confidence increased using CTAC as 80% of scans were interpreted as normal or abnormal, rather than equivocal, versus 57% of scans without AC (P \ 0.001). 22 Caobelli et al looked at 60 patients, 44 of which underwent coronary angiography, to compare the performance of CZT with and without CTAC. Interestingly, the authors found significantly improved diagnostic accuracy in the RCA territory (P = 0.002) but not in the LAD (P = 0.35) or LCx (P = 0.08) territories.…”

Technologist Approach to Global Dose Optimization

“…Among the hardware solutions, despite controversial issues (43), attenuation correction for MPI deserves a mention. The attenuation correction is particularly valuable in the setting of stress-only MPI, reducing the need for additional rest imaging by roughly a third (44) at the cost of a low-dose x-ray CT scan (45,46). CT attenuation correction plays a role in dose optimization for those patients in whom the stress scan has sufficient clinical information to avoid rest imaging, which would carry a 3-fold activity increase compared with stress imaging.…”