Quantification of regional myocardial blood flow using first-pass multidetector-row computed tomography compared with 201TL SPECT using adenosine triphosphate in coronary artery disease

Objectives The purpose of this study was to evaluate the detectability of myocardial ischemia with the first-pass perfusion MDCT imaging.The study group comprised 14 patients (11 men, 3 women, age range 52-79 years, mean age 69.2 years) who underwent cardiac cine MDCT using the ATP-load technique.

Methods Scan time was 30 seconds with breath hold. (120 kV, 40 mAs, 20 ml iohexol 300 and sarine 40ml @3ml/s). Time density curve was generated from the dynamic scan data, and this curve was analyzed with Patlac plot analysis. Thus, we got the MBF. MBF was estimated from the slope of the linear regression equation between Int_Cb(t)/Cb(t) and C(t)/Cb(t), where C(t) and Cb(t) represent the concentration of contrast agent at time t in the tissue and blood, respectively, and Int_Cb(t) the integral of Cb(t).

Results The overall average MBF was 1.83±0.62ml/g/min. Mean MBF in territories with stenosis on coronary angiography was 1.19±0.36ml/g/min and 2.06±0.54ml/g/min-1 (p<0.01) in territories without stenosis. The average MBF in territories with moderate to severe ischemia on myocardial perfusion scintigraphy was 1.32±0.14ml/g/min and 1.95±0.64ml/g/min (p<0.01) in territories without ischemia. Moderate to severe abnormal findings were seen in 6 of 14 patients (8 ischemic segments, 34 non-ischemic seg- ments) on 201Tl SPECT: 4 patients had 1-vessel disease, 2 had 2-vessel disease, and none had 3-vessel disease. Of the 8 ATP-loaded MPS-positive territories, 4 were in the LAD territory, 4 were in the RCA territory, and none were in the LCX territory. When the cutoff value of CT-MBF was set at 1.5ml/g/min, there was good correlation between CT-MBF and SPECT. CT-MBF vs SPECT: sensitivity=87.5%, specificity=79.4%, PPV=50.0%, NPV= 96.4%, accuracy=81.0%.

Conclusions MDCT can be used to quantify MBF using first-pass dynamic data as PET