Tumoral and Nontumoral Pancreas: Correlation between Quantitative Dynamic Contrast-enhanced MR Imaging and Histopathologic Parameters

Purpose: To prospectively determine whether dynamic contrast material-enhanced (DCE) magnetic resonance (MR) quantitative parameters correlate with fibrosis and microvascular density (MVD) in malignant and benign solid pancreatic focal lesions and nontumoral pancreatic tissue. Materials and Methods: The institutional review board approved the study; written informed consent was obtained. DCE MR was performed in 28 patients with surgically resectable focal pancreatic lesions. DCE MR quantitative parameters derived from one-compartment (OC) (transfer rate constant [K-trans] and distribution fraction [f]) and two-compartment (TC) (K-trans, tissue volume fraction occupied by extravascular extracellular space [v(i)], and tissue volume fraction occupied by vascular space [v(p)]) pharmacokinetic models were correlated with fibrosis content and MVD counts in focal lesions and nontumoral tissue (Spearman correlation coefficient [SCC]). Pharmacokinetic parameters were compared (Mann-Whitney test) between tumoral and nontumoral tissue. Diagnostic performance of DCE MR fibrosis detection was assessed (receiver operator characteristic curve analysis). Results: K-trans OC and K-trans TC were significantly lower in primary malignant tumors compared with benign lesions (P =.023) and nontumoral pancreatic tissue downstream (P < .001) and upstream (P =.006); and v(i) were significantly higher in primary malignant tumors compared with nontumoral pancreatic tissue downstream (P =.012 and.018, respectively). Fibrosis was correlated negatively with K-trans OC (SCC, -0.600) and K-trans TC (SCC, -0.564) and positively with f (SCC, 0.514) and v(i) (SCC, 0.464), with P < .001 (all comparisons). MVD was positively correlated with (SCC, 0.355; P =.019) and v(i) (SCC, 0.297; P =.038) but not with K-trans OC (SCC, 2 0.140; P =.33) and K-trans TC (SCC, -0.194; P =.181). Sensitivity and specificity for fibrosis detection were 65% (24 of 37) and 83% (10 of 12) for K-trans OC (cutoff value, 0.35 min(-1)) and 76% (28 of 37) and 83% (10 of 12) for K trans TC (cutoff value, 0.29 min(-1)), respectively. Conclusion: Quantitative DCE MR parameters, derived from pharmacokinetic models in malignant and benign pancreatic solid lesions and nontumoral pancreatic tissue, correlated with fi brosis and MVD. (C) RSNA, 2011