Quantitative upright-supine high-speed SPECT myocardial perfusion imaging for detection of coronary artery disease: correlation with invasive coronary angiography

Abstract

A recently developed camera system for high-speed SPECT (HS-SPECT) myocardial perfusion imaging shows excellent correlation with conventional SPECT. Our goal was to test the diagnostic accuracy of an automated quantification of combined upright and supine myocardial SPECT for detection of coronary artery disease (CAD) (≥ 70% luminal diameter stenosis or, in left main coronary artery, ≥ 50% luminal diameter stenosis) in comparison to invasive coronary angiography (ICA).

Methods: We studied 142 patients undergoing upright and supine HS-SPECT, including 56 consecutive patients (63% men; mean age ± SD, 64 ± 13 y; 45% exercise stress) without known CAD who underwent diagnostic ICA within 6 mo of HS-SPECT and 86 consecutive patients with a low likelihood of CAD. Reference limits for upright and supine HS-SPECT were created from studies of patients with a low likelihood of CAD. Automated software adopted from supine-prone analysis was used to quantify the severity and extent of perfusion abnormality and was expressed as total perfusion deficit (TPD). TPD was obtained for upright (U-TPD), supine (S-TPD), and combined upright-supine acquisitions (C-TPD). Stress U-TPD ≥ 5%, S-TPD ≥ 5%, and C-TPD ≥ 3% myocardium were considered abnormal for per-patient analysis, and U-TPD, S-TPD, and C-TPD ≥ 2% in each coronary artery territory were considered abnormal for per-vessel analysis.

Results: On a per-patient basis, the sensitivity was 91%, 88%, and 94% for U-TPD, S-TPD, and C-TPD, respectively, and specificity was 59%, 73%, and 86% for U-TPD, S-TPD, and C-TPD, respectively. C-TPD had a larger area under the receiver-operating-characteristic curve than U-TPD or S-TPD for identification of stenosis ≥ 70% (0.94 vs. 0.88 and 0.89, P < 0.05 and not significant, respectively). On a per-vessel basis, the sensitivity was 67%, 66%, and 69% for U-TPD, S-TPD, and C-TPD, respectively, and specificity was 91%, 94%, and 97% for U-TPD, S-TPD, and C-TPD, respectively (P = 0.02 for specificity U-TPD vs. C-TPD).

Conclusion: In this first comparison of HS-SPECT with ICA, new automated quantification of combined upright and supine HS-SPECT shows high diagnostic accuracy for detecting clinically significant CAD, with findings comparable to those reported using conventional SPECT.

FIGURE 1

Polar maps for stress ^99mTc-sestamibi perfusion imaging of LLk men (n = 30) and women (n = 30) show segmental comparison of sex-dependent upright, supine, and combined mean reference perfusion distribution. Average myocardial uptake between supine and upright in any of 17 segments for either men or women did not differ significantly.

FIGURE 2

Polar maps for stress ²⁰¹Tl perfusion imaging of LLk men (n = 15) and women (n = 11) show segmental comparison of sex-dependent upright, supine, and combined mean reference perfusion distribution. Average myocardial uptake between supine and upright in any of 17 segments for either men or women did not differ significantly.

FIGURE 3

(A) Example of inferolateral wall supine and upright MPS artifact images from 49-y-old woman with typical chest pain and known hypertension, diabetes, hypercholesterolemia, and family history of premature CAD. Images are displayed in 3 short-axis views and in vertical and horizontal long-axis views. Electrocardiogram response to exercise was nonischemic for ST-segment depression. Poststress supine and upright images show reduced uptake of radiotracer in inferolateral wall (top and middle rows). Blackout maps (bottom row) give quantification results of 4% for U-TPD and 6% for S-TPD. When supine and upright images are combined, only a small defect is visualized on black-out map, with C-TPD of 1%. Subsequent coronary angiogram showed no significant stenosis. (B) Example of true anteroseptal wall defect on supine and upright MPS images from 43-y-old man with typical chest pain and known hypercholesterolemia. Electrocardiogram response to exercise was ischemic for ST-segment depression, and subsequent coronary angiogram revealed severe stenosis of proximal left anterior descending coronary artery. Both supine and upright images show apparent anteroseptal wall perfusion abnormality, and U-TPD, S-TPD, and C-TPD are 29%, 24%, and 25%, respectively. Defects are visualized on black-out maps. HLA = horizontal long axis; SA = short axis; VLA = vertical long axis.

FIGURE 4

ROC curves for detection of CAD by measurements of U-TPD, S-TPD, and C-TPD in angiographic population (n = 56). Percentage TPD was compared with presence or absence of hemodynamically significant CAD as observed by ICA. U-TPD ≥ 5%, S-TPD ≥ 5%, and C-TPD ≥ 3% were used as cutoff points.

FIGURE 5

Sensitivities and specificities for detection of CAD by U-TPD, S-TPD, and C-TPD in angiographic population (n = 56).