Table 1.
Symbols and definitions for kinetic parameters.
Fig 1.
Example of fitting of arterial and portal-venous curves and tissue enhancement curves with various models.
Graphs illustrate examples of (A and B) fitting of the arterial and portal input enhancement curves, (C and D) fitting of the five different models to a voxel enhancement curve which was sampled from the HCC, and (E and F) their corresponding impulse response curves (i.e., QT(t) = (F/VT) ⋅ RT(t)) where two different cases are shown in the left and right columns. WX = water-exchange-modified, TK = Tofts-Kety, ETK = extended Tofts-Kety. 2CX = two compartment exchange, AATH = adiabatic approximation to tissue homogeneity, and DP = distributed parameter.
Fig 2.
Example of kinetic parameter maps derived from various models.
Parametric maps of total hepatic blood flow (BF), arterial flow fraction (γ), arterial blood flow (BFA), portal blood flow (BFPV), blood volume (BV), mean transit time (MTT), capillary wall permeability-surface area product (PS), fractional interstitial volume (vI), extraction fraction (E), mean intracellular water molecule lifetime (τC), and fractional intracellular volume (vC) for HCC in (A) a low-risk man aged 52 years who survived for 23.87 months, and (B) a high-risk man aged 72 years who survived for 8.53 months. WX = water-exchange-modified, TK = Tofts-Kety, ETK = extended Tofts-Kety, 2CX = two compartment exchange, AATH = adiabatic approximation to tissue homogeneity, and DP = distributed parameter.
Table 2.
Parameter values derived from the five different WX kinetic models.
Fig 3.
Kaplan-Meier curves for kinetic parameters predictive of 1-year survival.
Cross-validated Kaplan-Meier plots for (A) arterial flow fraction (γ) and (B) fractional interstitial volume (vI) derived from the water-exchange-modified Tofts-Kety (WX-TK) model, and (C) mean intracellular water molecule lifetime (τC) and (D) fractional intracellular volume (vC) derived from the water-exchange-modified extended Tofts-Kety (WX-ETK) model. Survival of patients with advanced HCC treated with sunitinib was better with γ over 0.833 and vI over 0.300 in the WX-TK model, and with τC at most 0.927 sec and vC at most 0.611 in the WX-ETK model.
Table 3.
Optimal cut-off values of parameters and their log-rank test results from leave-one-out cross-validated Kaplan-Meier analysis in terms of 1-year survival.
Table 4.
Results of univariate Cox’s proportional hazards regression analysis of parameters in terms of overall survival.