Quantitative high-efficiency cadmium-zinc-telluride SPECT with dedicated parallel-hole collimation system in obese patients: Results of a multi-center study

Abstract

Background Obesity is a common source of artifact on conventional SPECT myocardial perfusion imaging (MPI). We evaluated image quality and diagnostic performance of high-efficiency (HE) cadmium-zinc-telluride (CZT) parallel-hole SPECT-MPI for coronary artery disease (CAD) in obese patients. Methods and Results 118 consecutive obese patients at 3 centers (BMI 43.6±8.9 kg/m2, range 35–79.7 kg/m2) had upright/supine HE-SPECT and ICA >6 months (n=67) or low-likelihood of CAD (n=51). Stress quantitative total perfusion deficit (TPD) for upright (U-TPD), supine (S-TPD) and combined acquisitions (C-TPD) was assessed. Image quality (IQ; 5=excellent; <3 nondiagnostic) was compared among BMI 35–39.9 (n=58), 40–44.9 (n=24) and ≥45 (n=36) groups. ROC-curve area for CAD detection (≥50% stenosis) for U-TPD, S-TPD, and C-TPD were 0.80, 0.80, and 0.87, respectively. Sensitivity/specificity was 82%/57% for U-TPD, 74%/71% for S-TPD, and 80%/82% for C-TPD. C-TPD had highest specificity (P=.02). C-TPD normalcy rate was higher than U-TPD (88% vs. 75%, P=.02). Mean IQ was similar among BMI 35–39.9, 40–44.9 and ≥45 groups [4.6 vs. 4.4 vs. 4.5, respectively (P=.6)]. No patient had a non-diagnostic stress scan. Conclusions In obese patients, HE-SPECT MPI with dedicated parallel-hole collimation demonstrated high image quality, normalcy rate, and diagnostic accuracy for CAD by quantitative analysis of combined upright/supine acquisitions.

Refining risk in diabetes and CAD with SPECT MPI: New insights and future challenges

“…BMI was higher in the DM groups, and neither attenuation correction nor parallel hole CZT SPECT MPI was used, which enhances diagnostic accuracy for detection of angiographic stenosis in obese patients. 26 The findings of this landmark Morales study support the concept of CAD risk equivalence of diabetes and CAD in a population more than seven times larger than that studied in the original Haffner East West study. 5 They also support AHA guidelines which recommend treating CAD risk factors in DM patients without CAD as aggressively as in non-diabetic patients with CAD.…”

What do we know? What do we need to know?

“…The literature suggests that perhaps D-SPECT camera (Spectrum Dynamics) is more suitable for imaging obese patients compared to the Discovery 530 (GE Healthcare). 22 What do we need to know in the future? Only preliminary data are available for some of the following: should include solid-state cameras for time to diagnosis, radiation dose, and cost effectiveness.…”

Diagnostic implications of CZT SPECT and impact of CT attenuation correction

“…6 Supine and upright imaging with CZT in obese patients has also demonstrated diagnostic accuracy for CAD. 13,14 Although these techniques have been used, more recently hybrid SPECT/CT systems allow for high-quality attenuation maps due to improved signal-to-noise ratio and better resolution. 15 CTAC for conventional SPECT imaging has been validated to improve diagnostic accuracy and risk stratification compared with non-attenuation (NAC) corrected imaging.…”