Myocardial Perfusion SPECT Imaging of Obese Patients on Cadmium Zinc Telluride (CZT) Camera

Nadine Mallak; Yusuf Menda

Objectives: CZT cameras provide high quality myocardial perfusion scans (MPS), however, the image quality and accuracy of CZT MPS using a stress-first protocol is less well validated in obese patient population. The purpose of our study is to evaluate the image quality and accuracy of CZT MPS in patients with BMI above 35. Methods: A retrospective analysis of all patients with BMI above 35 who underwent stress-first (rest images obtained only if stress is abnormal) CZT MPS between January 1st 2015 and October 30 2015. All stress myocardial perfusion scans including supine and prone images were interpreted independently by two reviewers blinded to history and prior imaging with a final consensus reading. The quality of the MPS was graded on a scale from 1 to 4 (1: Poor/Non-diagnostic; 2: Borderline; 3: Good; 4: Excellent). The interpretation of MPS followed a 5-point scale (1: Abnormal, 2: Probably Abnormal, 3: Equivocal, 4: Probably Normal and 5: Normal). Patient follow-up data was obtained from electronic charts. Coronary events were defined as cardiac death, nonfatal myocardial infarction and revascularization. Results: 105 patients, 65 males and 40 females, age range 37-87, were evaluated. The BMI of the patients ranged from 35.1 to 42.7 (median = 36.9). The image quality score was assessed as 3 or 4 in 83 patients (79.1 %), 2 in 18 patients (17.1%) and 1 in 4 patients (3.8%). 70 patients (66.7%) had normal or probably normal scans, 17 (16.2%) patients had abnormal or probably abnormal stress scans and 18 (17.1 %) patients had equivocal stress scans. 8 patients had no follow-up visit; in the remaining 97 patients, the median follow-up was 16.1 months (range: 0.7 to 23.1 months). There were a total of 6 cardiac events in the entire patient population. In 70 patients with normal/probably normal scans, there was 1 coronary event (1.4%) over a follow-up period of a median of 16.3 months (range: 3.1 to 23.1 months; at least 12 months in 51 patients). In 18 patients with equivocal scans there was 1 coronary event (5.55%) over a follow-up period of a median of 15.1 months (range: 0.7 to 20.6 months). There were 4 cardiac events In 17 patients with abnormal scans (23.5%, P<0.01 compared to normal group). Conclusion: CZT MPS stress-first myocardial perfusion imaging provides high-quality images in the vast majority of obese patients and identifies patients at high-risk for coronary events.

Myocardial Perfusion SPECT Imaging of Obese Patients on Cadmium Zinc Telluride (CZT) Camera

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