MDCT findings of extrapancreatic nerve plexus invasion by pancreas head carcinoma: correlation with en bloc pathological specimens and diagnostic accuracy

To elucidate the multi-detector row computed tomography (MDCT) findings of extrapancreatic nerve plexus (PLX) invasion by pancreas head carcinoma (PhC) by point-by-point correlation with en bloc pathological specimens and to assess their diagnostic accuracy. Each pathological section of PhC and adjusted double oblique multiplanar reconstruction MDCT images were correlated in 554 sections from 37 patients. The diagnostic accuracy of the MDCT patterns derived was assessed by blind reading. PLX invasion with fibrosis showed mass or strand shape (85.6%) or coarse reticula (13.3%). The CT findings were divided into fine reticular and linear, coarse reticular, mass and strand, and nodular patterns. PLX invasion was revealed pathologically in 92% of the regions of investigation showing the mass and strand pattern and 63% of the coarse reticular pattern (all continuous with PhC), and they were highly suggestive of PLX invasion by PhC on MDCT images (p < 0.001). Sensitivity, specificity, accuracy, and positive and negative predictive values of these MDCT findings in the diagnosis of PLX invasion were 100% (25/25), 83.3% (10/12), 94.6% (35/37), 92.6% (25/27) and 100% (10/10), respectively. The mass and strand pattern and the coarse reticular pattern continuous with PhC on MDCT images were highly suggestive of PLX invasion by PhC.