TY - JOUR
T1 - Underestimation of myocardial blood flow by dynamic perfusion CT
T2 - Explanations by two-compartment model analysis and limited temporal sampling of dynamic CT
AU - Ishida, Masaki
AU - Kitagawa, Kakuya
AU - Ichihara, Takashi
AU - Natsume, Takahiro
AU - Nakayama, Ryohei
AU - Nagasawa, Naoki
AU - Kubooka, Makiko
AU - Ito, Tatsuro
AU - Uno, Mio
AU - Goto, Yoshitaka
AU - Nagata, Motonori
AU - Sakuma, Hajime
N1 - Publisher Copyright:
© 2016 Society of Cardiovascular Computed Tomography
PY - 2016/6/1
Y1 - 2016/6/1
N2 - Purpose Previous studies using dynamic perfusion CT and volume perfusion CT (VPCT) software consistently underestimated the stress myocardial blood flow (MBF) in normal myocardium to be 1.1–1.4 ml/min/g, whilst the O 15-water PET studies demonstrated the normal stress MBF of 3–5 ml/min/g. We hypothesized that the MBF determined by VPCT (MBF-VPCT) is actually presenting the blood-to-myocardium transfer constant, K1. In this study, we determined K1 using Patlak plot (K1-Patlak) and compared the results with MBF-VPCT. Material and methods 17 patients (66 ± 9 years, 7 males) with suspected coronary artery disease (CAD) underwent stress dynamic perfusion CT, followed by rest coronary CT angiography (CTA). Arterial input and myocardial output curves were analyzed with Patlak plot to quantify myocardial K1. Significant CAD was defined as >50% stenosis on CTA. A simulation study was also performed to investigate the influence of limited temporal sampling in dynamic CT acquisition on K1 using the undersampling data generated from MRI. Results There were 3 patients with normal CTA, 7 patients with non-significant CAD, and 7 patients with significant CAD. K1-patlak was 0.98 ± 0.35 (range 0.22–1.67) ml/min/g, whereas MBF-VPCT was 0.83 ± 0.23 (range 0.34–1.40) ml/min/g. There was a linear relationship between them: (MBF-VPCT) = 0.58 x (K1-patlak) + 0.27 (r2 = 0.65, p < 0.001). The simulation study done on MRI data demonstrated that Patlak plot substantially underestimated true K1 by 41% when true K1 was 2.0 ml/min/g with the temporal sampling of 2RR for arterial input and 4RR for myocardial output functions. Conclusions The results of our study are generating hypothesis that MBF-VPCT is likely to be calculating K1-patlak equivalent, not MBF. In addition, these values may be substantially underestimated because of limited temporal sampling rate.
AB - Purpose Previous studies using dynamic perfusion CT and volume perfusion CT (VPCT) software consistently underestimated the stress myocardial blood flow (MBF) in normal myocardium to be 1.1–1.4 ml/min/g, whilst the O 15-water PET studies demonstrated the normal stress MBF of 3–5 ml/min/g. We hypothesized that the MBF determined by VPCT (MBF-VPCT) is actually presenting the blood-to-myocardium transfer constant, K1. In this study, we determined K1 using Patlak plot (K1-Patlak) and compared the results with MBF-VPCT. Material and methods 17 patients (66 ± 9 years, 7 males) with suspected coronary artery disease (CAD) underwent stress dynamic perfusion CT, followed by rest coronary CT angiography (CTA). Arterial input and myocardial output curves were analyzed with Patlak plot to quantify myocardial K1. Significant CAD was defined as >50% stenosis on CTA. A simulation study was also performed to investigate the influence of limited temporal sampling in dynamic CT acquisition on K1 using the undersampling data generated from MRI. Results There were 3 patients with normal CTA, 7 patients with non-significant CAD, and 7 patients with significant CAD. K1-patlak was 0.98 ± 0.35 (range 0.22–1.67) ml/min/g, whereas MBF-VPCT was 0.83 ± 0.23 (range 0.34–1.40) ml/min/g. There was a linear relationship between them: (MBF-VPCT) = 0.58 x (K1-patlak) + 0.27 (r2 = 0.65, p < 0.001). The simulation study done on MRI data demonstrated that Patlak plot substantially underestimated true K1 by 41% when true K1 was 2.0 ml/min/g with the temporal sampling of 2RR for arterial input and 4RR for myocardial output functions. Conclusions The results of our study are generating hypothesis that MBF-VPCT is likely to be calculating K1-patlak equivalent, not MBF. In addition, these values may be substantially underestimated because of limited temporal sampling rate.
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U2 - 10.1016/j.jcct.2016.01.008
DO - 10.1016/j.jcct.2016.01.008
M3 - Article
C2 - 26851149
AN - SCOPUS:84956642647
SN - 1934-5925
VL - 10
SP - 207
EP - 214
JO - Journal of Cardiovascular Computed Tomography
JF - Journal of Cardiovascular Computed Tomography
IS - 3
ER -