Diagnostic Accuracy of low dose thallium-201 myocardial perfusion imaging with cadmium-zinc-telluride camera compared to coronary angiography and fractional flow reserve

Objectives Recently introduced cadmium-zinc-telluride (CZT) single photon emission tomography (SPECT) myocardial perfusion imaging (MPI) offers excellent image quality with short acquisition time, but there has been no validation of diagnostic performance of CZT SPECT camera using low dose of thallium-201. We compared the diagnostic accuracy of reduced dose CZT SPECT MPI to coronary angiography (CAG) and fractional flow reserve (FFR) as the reference standard.

Methods We retrospectively reviewed the data of all consecutive patients who underwent low dose thallium-201 MPI (44.4 MBq in patients <70kg, 55.5 MBq in patients 蠅70kg) with CZT camera (Discovery NM 530c, GE healthcare) and CAG and FFR within 3 months, between March 2015 and November 2015. Patients with a history of coronary artery bypass grafting surgery, and severe LV hypertrophy were excluded. Adenosine stress and rest images were acquired in supine position for 6 min, respectively. CZT SPECT images were interpreted by two nuclear medicine physicians blinded to the clinical results, using 17-segment model with 5-grade scoring system. A lesion with 蠅90% diameter narrowing, or <90% and 蠅50% diameter narrowing and FFR &#8804;0.75 was defined as significant stenosis on CAG.

Results A total of 74 patients were analyzed with a mean age of 63 ± 10 years (52 men and 22 women). Among them, 3-vessel coronary artery disease (CAD) was observed in 5 patients, 2-vessel CAD in 14, and 1-vessel CAD in 24. The diagnostic sensitivity and specificity were 95% and 74% on a per-patient basis, and 68% and 92% on a per-vessel basis. For detecting individual coronary artery stenosis, the diagnostic sensitivity and specificity were 89% and 85% for left anterior descending coronary artery, 63% and 95% for left circumflex artery, and 75% and 94% for right coronary artery, respectively.

Conclusions With low dose of thallium-201, CZT SPECT MPI demonstrated a high diagnostic performance in assessing significant coronary stenosis. More studies are needed to evaluate the clinical implication of lesions with significant stenosis on CAG and FFR but normal on CZT SPECT MPI.