Quantitative Analysis of First-Pass Contrast-Enhanced Myocardial Perfusion Multidetector CT Using a Patlak Plot Method and Extraction Fraction Correction During Adenosine Stress

The purpose of this study was to develop a quantitative method for myocardial blood flow (MBF) measurement that can be used to derive accurate myocardial perfusion measurements from dynamic multidetector computed tomography (MDCT) images by using a compartment model for calculating the first-order transfer constant (
K
₁
) with correction for the capillary transit extraction fraction (
E
). Six canine models of left anterior descending (LAD) artery stenosis were prepared and underwent first-pass contrast-enhanced MDCT perfusion imaging during adenosine infusion (0.14-0.21 mg/kg/min).
K
₁
, which is the first-order transfer constant from left ventricular (LV) blood to myocardium, was measured using the Patlak plot method applied to time-attenuation curve data of the LV blood pool and myocardium. The results were compared against microsphere MBF measurements, and the extraction fraction of contrast agent was calculated.
K
₁
is related to the regional MBF as
K
₁
=
EF
,
E
=(1-
exp
(-
PS
/
F
)), where
PS
is the permeability-surface area product and
F
is myocardial flow. Based on the above relationship, a look-up table from
K
₁
to MBF can be generated and Patlak plot-derived
K
₁
values can be converted to the calculated MBF. The calculated MBF and microsphere MBF showed a strong linear association. The extraction fraction in dogs as a function of flow (
F
) was
E
=(1-
exp
(-(0.2532
F
+0.7871)/
F
)) . Regional MBF can be measured accurately using the Patlak plot method based on a compartment model and look-up table with extraction fraction correction from
K
₁
to MBF.