Improved detection of coronary artery disease by CZT regional coronary blood flow evaluation

Abstract

IntroductionCZT cameras have enabled the noninvasive quantification of myocardial flow reserve (MFR), an important physiologic measure. This study aimed to compare myocardial perfusion SPECT (MPS) with or without MFR evaluation for the detection of obstructive coronary artery disease (CAD).Methods48 patients with CAD (>50% obstruction) detected at invasive coronary angiography or CT angiography underwent dipyridamole MPS and MFR evaluation within 30 days. A 1-day protocol (rest-stress) was used to quantify MFR. The acquisition of dynamic rest and stress images was initiated simultaneously to 99mTc sestamibi injection (370 and 1,110 MBq, respectively), both lasting for 11 min, followed by 5-min imaging. Pharmacologic stress with dipyridamole (0.56 mg/kg for 4 min) was performed with the patient positioned in the CZT camera. The images were processed and time-activity curves were generated, calculating global and regional MFR in a semiautomatic software. A global or regional MFR <2 was considered abnormal. MPS perfusion images were classified as normal or abnormal. The images were interpreted by experienced physicians blinded to the results of MFR and coronary angiography/CT.ResultsMean age of the population was 61 ± 9 years, 54.2% female. Twenty patients (41.7%) had single-vessel CAD, 22 (45.8%) 2-vessel CAD and 6 (12.5%), triple-vessel CAD. Among the 82 vessels with obstruction, 48 had perfusion abnormalities in MPS and 60 had reduced MFR, while among the normal vessels, had 54 normal MPS and 52 had preserved MFR. The sensitivity of MFR (69%) was higher than that of MPS (55.2%), without significant changes in specificity (86 vs. 83.7%).ConclusionsMFR in the CZT camera is more sensitive for the detection of CAD than perfusion abnormalities in MPS, especially in patients with multivessel CAD.

Impacto Clínico da Avaliação da Reserva de Fluxo Miocárdico na Identificação da Causa do Desconforto Torácico

“…No estudo de Patel, menos de 50% com angina tinham lesão coronariana significativa. 17 Estudos com tomografia de emissão de pósitrons mostram que a alteração de RFM pode, além de aumentar a sensibilidade para detectar DAC, identificar a doença microvascular como causa de desconforto torácico. 11 …”

“…As gama-câmaras com detectores de CZT vêm se revelando uma alternativa para avaliação de RFM. O estudo de Souza et al 13 revelou que essa técnica é factível e o estudo de Lima et al 17 demonstrou uma acurácia maior na detecção de doença coronariana obstrutiva.…”

“…Conforme demonstrado anteriormente, o uso da RFM aumenta a acurácia da CPM para detecção de DAC obstrutiva. No estudo de Lima et al, 17 a sensibilidade foi de 55,2% e 69% da CPM e da RFM respectivamente. No presente estudo foi de 60% e 79,1%, mas por paciente e não por vaso como analisado no estudo anterior.…”

“…In the study by Patel et al, less than 50% of patients with angina had significant coronary lesions. 17 Studies with positron emission tomography show that changes in MFR can, in addition to increasing sensitivity to detect CAD, identify microvascular disease as the cause of chest discomfort. 11 …”

“…Gamma cameras with CZT detectors have proven to be an alternative for assessing MFR The study by Souza et al 13 revealed that this technique is feasible and the study by Lima et al 17 demonstrated greater accuracy in detecting obstructive coronary disease.…”