Gated-SPECT myocardial perfusion imaging: Early 5 vs 30 minutes post-stress acquisition, to assess extent of ischaemia

1793 Objectives Aim of the study was to evaluate clinical implications of early post-stress Gated-SPECT[G-SPECT] myocardial perfusion images using HR matrix [128x128pxls] and iterative reconstruction. Methods Methods: We studied 73 consecutive pts [73 M; 10 F] with suspected [22] or known [51] CAD [48 post-revascularization]. All but 4[Dipyidamole+exercise] pts underwent exercise stress-test: at peak 555MBq Tetrofosmin was injected. After 5[GSP5] and 30[GSP30]minutes G-SPECT acquisitions were obtained. Four hours later rest G-SPECT[GSPR] was repeated[740MBq]. G-SPECT was performed using double head GC with HR-collimator in 90° configuration; [128x128pxls matrix,12 frames/cycle]. Transaxial images were reconstructed with ramp-Butterworth filtering (cutoff 0.3-7) for Gated images; while iterative [OSEM2D,2 subsets,10 iterations, gauss 6] for SPECT. Short-and-long (sagittal-horizontal)-axis oblique slices were obtained by reorienting transaxial image data. Both perfusion quantification (QPS, Cedars Sinai) and ventricular function (QGS, Cedars Sinai ) were calculated: Rest/Stress regional Wall Motion was assessed. Results Results: In all patients we obtained myocardial perfusion images of high quality particularly in GSP5: no significant differences were observed in lung/heart, liver/heart ratio. The extent of defects was similar in #segments [117/117] and score [SSS 5.10/5.06; SRS 4.16, SDS 0.97/0.96] respectively for GSP5, GSP30 compared to GSPR groups. No significant differences in quantitated functional data [EF 56.67; 56.85; 54.96%; EDV 127.88; 124.45; 128ml; for GSPR,GSP5, GSP30 respectively] were found in the 3 groups. The only significant difference was observed in segmental Wall Motion abnormalities [score WM 4.96; 6.25; 5.89]. Conclusions Conclusions: Early G-SPECT is quite feasible, less time consuming, allows to obtain images of high quality and to augment diagnostic accuracy of the procedure better identifying site and extent of ischaemia in terms of myocardium stunning