Dynamic Perfusion Computed Tomography and Apparent Diffusion Coefficient as Potential Markers for Poorly Differentiated Pancreatic Adenocarcinoma.

INTRODUCTION Tumor grade, one of the most important risk factors for survival, is routinely determined after examining the biopsy material or a surgically removed specimen. The aim of the study was to analyze computed tomography (CT) perfusion parameters and diffusion-weighted imaging apparent diffusion coefficient (ADC) values in pancreatic ductal adenocarcinoma (PDAC) and to establish the diagnostic value of these modalities determining the tumor grade. MATERIALS AND METHODS A prospective clinical study included 56 subjects with PDAC. All the patients had a local perfusion assessment and ADC measurement of the tumor. For the prediction of poor tumor differentiation sensitivity, specificity, positive, and negative predictive values for each perfusion CT and ADC parameters based on cutoff values from ROC analysis were calculated. RESULTS Mean transit time (MTT) and ADC values were found to be independent prognosticators for the presence of G3 PDAC. MTT and ADC at the cutoff of 17.37 s and 1.15 × 10-3 mm2/s, respectively, appeared to be significant parameters discriminating against the differentiation grade of PDAC. If both values exceeded the defined cutoff point, the estimated probability for the presence of G3 PDAC was 89.29%. CONCLUSION The MTT parameter, calculated with the deconvolution method, and the ADC value may serve as effective independent prognosticators identifying poorly differentiated PDAC.