Imaging of early pancreatic cancer on multidetector row helical computed tomography

Early pancreatic cancer is small and limited to the pancreas. In contrast, small pancreatic cancer may include peripancreatic vasculature or metastasis involvement. This study evaluates images of early pancreatic cancer on multidetector CT (MDCT) using contrast-enhanced multiphasic imaging, and post-processed pancreatic duct images. CT findings and pathological features were analysed in eight patients with early pancreatic cancer. Pathological evaluation included location, size and histological grading of the tumour. MDCT evaluation covered the maximum diameter of the main pancreatic duct (MPD), stenosis or obstruction of the MPD, loss of normal lobar texture and associated pancreatitis. Attenuation differences between normal pancreatic parenchyma and the tumour (AD-PT) were also measured. Focal stenosis or obstruction of the MPD with dilatation of the distal MPD was demonstrated in all patients. Associated pancreatitis occurred in six patients with tumours measuring 12 mm or greater. Loss of normal lobar texture was recognised in four cases with the tumour measuring 14 mm or greater. Statistically, low-attenuated lesions and high-attenuated lesions differed with respect to the tumour size (p<0.01), and a positive relationship was demonstrated between the tumour size and AD-PT (r = 0.84). In seven cases, AD-PT is higher during the arterial phase than the pancreatic phase. Early pancreatic cancer appears as low attenuation on early phase, and as high- to iso-attenuation during the pancreatic and delayed phases in respect to the tumour size. Focal stenosis or obstruction of the MPD with dilatation of the distal MPD observed on curved reformation imaging seems important in the diagnosis of early pancreatic cancer.