Abstract 10248: Prognosis and Resource Utilization in Patients Undergoing SPECT MPI Using Supine-Prone Image Acquisition and a CZT Camera
Newer cadmium-zinc-telluride (CZT) detectors offer the potential for improved spatial and temporal performance for SPECT myocardial perfusion imaging (MPI). However, the optimal strategy for attenuation correction (AC) using CZT is unclear.
Objective: to assess the prognostic utility of supine-prone imaging using CZT SPECT MPI.
Methods: We studied clinical and imaging outcomes in 748 consecutive patients (Pts) 56% male, age 59 ± 1 (mean ± SE) who underwent supine-prone stress CZT SPECT MPI (99Tc-tetrofosmin). Supine images were obtained at rest and after stress. For the purpose of AC, prone images were also obtained after stress. The indication for MPI was chest pain or dyspnea in 91%. Pts had 3 ± 1 known risk factors for coronary artery disease (CAD; range: 0 - 7). Follow-up was available in 93% of Pts, for 363 ± 2 days (range: 276 - 457).
Results: After stress, 270 Pts. had no perfusion defects (NL group), 309 Pts. had supine stress perfusion defects that all resolved with prone imaging (NL-Prone group), and 169 pts. had stress perfusion defects that persisted with prone imaging (ABNL group). In NL-Prone, 91% of supine defects were in the inferior LV wall, compared to 58% in ABNL. In 61% of males, vs. 70% of females, all supine perfusion defects resolved with prone imaging (p = 0.06). During follow-up, death/MI occurred in 2.3% of NL, 2.9% of NL-Prone (p = 0.83 vs. NL), vs. 5.9% of ABNL (p = 0.06 vs. NL + NL-Prone). Invasive coronary angiography was performed during follow-up in 4.1 % of NL, 4.9 % of NL-Prone (p = 0.80), and in 46% of ABNL (p < 0.001). Coronary revascularization was required in 1.1% of NL, 1.6% of NL-Prone (p = 0.93), and 17.8% of ABNL (p < 0.001). The somewhat low rate of revascularization among ABNL may have been due to a high rate of known pre-existing CAD (67%).
Conclusions: Attenuation artifacts are common with supine CZT SPECT MPI. Prone imaging provides sufficient AC, without the need for additional external radiation, to identify patients with short-term risk for death/MI/revascularization that is comparable to patients who demonstrate no regional perfusion defects on MPI. Utilization of prone imaging for AC may reduce unnecessary exposure to the risks of invasive coronary angiography in patients with intermediate risk of obstructive CAD.
- © 2013 by American Heart Association, Inc.