Tetrofosmin early time gated post-stress single-photon emission computed tomography imaging: Feasibility and potential benefits

Abstract

BackgroundThe purpose of this study is to evaluate the feasibility, the image quality, and the clinical relevance of an early gated post-stress (GPS) single-photon emission computed tomography (SPECT) tetrofosmin (Myoview™—GE Healthcare) acquisition protocol. Time delay between myocardial technetium-labeled tracer administration and SPECT acquisition is usually about 30 minutes after stress, and 45 to 60 minutes at rest: because of the absence of significant redistribution, perfusion images are related to stress even 30 minutes after stress injection, while function and thickening data obtained with gated acquisition 30 minutes after stress are mainly related to rest conditions.Methods194 patients were prospectively included and analyzed, in a multicenter registry. Three gated-SPECT 99mTc-Tetrofosmin studies were performed per patient: GPS-SPECT, 30 minutes post-stress (GS30), and at rest (GR30).ResultsGPS image quality was excellent/good (93.9%), and similar to GS30 images (96.6%). The presence of adjacent myocardial sub-diaphragmatic activity on GPS images was similar to GS30 images (24% vs 22%), and less frequent than on GR30 images (31%). For perfusion, thickening, and motion scores, there was no significant difference between early and 30 minute post-stress in the global patient population, but significant differences were observed between GPS and GS30 for LVEF (65% ± 15% vs 63% ± 14%). In the ischemic patients, with the stress-rest protocol, the perfusion score was 14.2 on GPS images and 12.4 on GS30 images (P = .002).ConclusionsTetrofosmin early GPS-SPECT is feasible without impairment of image quality (better count rate). Ischemic defect size on early post-stress images is slightly more pronounced than at 30 minutes: this could modify therapeutic decision. This technique produces reliable function information during early post-stress period, and might be useful for disclosing transient motion abnormalities.

Relevance of early poststress variation in left ventricular function studied by gated-SPECT

“…These findings are in agreement with the EF values in negative patients as recently reported by Philippe et al [16]. Patients with negative perfusion scintigraphy constituted the control group.…”

“…The long-term prognostic value of poststress EF in addition to SDS or SSS in predicting adverse cardiac events, myocardial infarction, or cardiac death has already been shown in previous studies [9][10][11][12][13][14][15][16][17][18][19]22]; however, our report emphasizes the importance of early postexercise EF evaluation for referring patients for coronary angiography and revascularization. Resting EF does not reflect poststress stunning, and the prognostic value of poststress EF may be attributed to the transient worsening of ventricular function in patients with stressinduced ischemia and extensive coronary disease.…”

“…As previously described, 99m Tc-tetrofosmin perfusion imaging can be started even 5 min after stress injection, and it has been recently shown that early poststress SPECT did not impair image quality, producing reliable function information [13,16]. The limitation of poststress EF evaluation is that it varies according to the time delay between exercise and acquisition start.…”

Fast myocardial perfusion imaging with 99mTc in challenging patients using conventional SPECT cameras

“…The latter difference was largely limited to patients undergoing adenosine stress, an observation compatible with the classic knowledge that stress with vasodilators is associated with a higher risk of subdiaphragmatic 99m Tc activity compared to exercise. Hence, our findings support the feasibility of early imaging and are in agreement with more recent, non-controlled 19,20 and controlled 8,21 studies, which have also demonstrated the feasibility of early imaging in terms of image quality appropriate for reliable interpretation. Furthermore, in our study the Early imaging protocol had similar diagnostic accuracy with the Late imaging protocol, demonstrating that early imaging is both technically feasible and diagnostically sufficient compared with the established imaging protocol.…”

Myocardial perfusion imaging with 99mTc-labeled radiopharmaceuticals: How fast can a stress-rest same-day imaging protocol be completed?

“…They confirmed results from previous studies evaluating the same issues. [16][17][18] A fast MPI protocol including both rest and stress studies has several clinical implications. On the practical side, it offers a shorter waiting times and convenience to the patient and it increases the laboratories efficiency, possibly doing more studies per day.…”