review of literature on clinical pancreatology - The Pancreapedia

enhancement on the portal venous phase, the absence <strong>of</strong> significant upstream mainpancreatic duct dilatation greater than 5 mm, and the absence <strong>of</strong> proximal pancreaticatrophy, then conducting further evaluations should be considered to avoid performingunnecessary surgery [313].The purposes <strong>of</strong> one study were to define the pancreatic enhancement <strong>of</strong> autoimmunepancreatitis at dual-phase CT and to compare it with that <strong>of</strong> pancreatic carcinoma and anormal pancreas. Dual-phase CT scans <strong>of</strong> 101 patients (43 with autoimmune pancreatitis, 13cases <strong>of</strong> which were focal; 33 with pancreatic carcinoma, and 25 with a normal pancreas)were evaluated. One radiologist measured the CT attenuation <strong>of</strong> the pancreatic parenchymaand pancreatic masses in both the pancreatic and hepatic phases <strong>of</strong> imaging. The mean CTattenuation value <strong>of</strong> the pancreatic parenchyma in patients with autoimmune pancreatitis wascompared with that in patients with a normal pancreas. The mean CT attenuation value <strong>of</strong>the focal masses in the focal form <strong>of</strong> autoimmune pancreatitis was compared with that <strong>of</strong>carcinomas. In the pancreatic phase, the mean CT attenuation value <strong>of</strong> the pancreaticparenchyma in patients with autoimmune pancreatitis was significantly lower than that inpatients with a normal pancreas (autoimmune pancreatitis, 85 HU; normal pancreas, 104HU). In the hepatic phase, however, the mean CT attenuation values were not significantlydifferent (autoimmune pancreatitis, 96 HU; normal pancreas, 89 HU). In the pancreaticphase, the mean CT attenuation value <strong>of</strong> the mass in autoimmune pancreatitis was notsignificantly different from that <strong>of</strong> carcinoma (autoimmune pancreatitis, 71 HU; carcinoma, 59HU), but in the hepatic phase, the value was significantly higher than that <strong>of</strong> carcinoma(autoimmune pancreatitis, 90 HU; carcinoma, 64 HU). It was concluded that at dual-phaseCT, the enhancement patterns <strong>of</strong> the pancreas and pancreatic masses in patients withautoimmune pancreatitis are different from those <strong>of</strong> pancreatic carcinoma and normalpancreas [314].PET-CT for differential diagnosisOne study was conducted to evaluate the clinical usefulness <strong>of</strong> PET/CT in differentiatingautoimmune pancreatitis from pancreatic cancer. It was analyzed the cases <strong>of</strong> 17 patientswith autoimmune pancreatitis and atypical pancreatic imaging findings who underwentintegrated PET/CT. The PET/CT findings on the 17 patients with autoimmune pancreatitiswere compared with those <strong>of</strong> 151 patients with pancreatic cancer. Fluorine-18 FDG uptakeby the pancreas was found in all patients with autoimmune pancreatitis and in 82 percent(124/151) <strong>of</strong> patients with pancreatic cancer. Diffuse uptake by the pancreas wassignificantly more frequent in patients with autoimmune pancreatitis (53 % vs 3 %). FDGuptake by the salivary glands and kidneys was seen only in patients with autoimmunepancreatitis, the former reaching statistical significance. Follow-up PET/CT after steroidtherapy was performed for eight patients with autoimmune pancreatitis. After steroid therapy,none <strong>of</strong> the patients had intense FDG uptake by the pancreas or extrapancreatic organs. Itwas concluded that in difficult cases, at PET/CT the presence <strong>of</strong> diffuse uptake <strong>of</strong> FDG bythe pancreas or concomitant extrapancreatic uptake by the salivary glands can be used toaid in differentiation <strong>of</strong> autoimmune pancreatitis and pancreatic cancer [315].Positrone emission tomographyThe aim <strong>of</strong> one study was to analyze the usefulness <strong>of</strong> positron emission tomography with18 F-fluorodeoxyglucose (FDG-PET) in the evaluation <strong>of</strong> distribution and activity <strong>of</strong> systemiclesions <strong>of</strong> AIP during steroid therapy. Eleven cases <strong>of</strong> autoimmune pancreatitis had theirFDG-PET images evaluated before and 3 months after steroid therapy and another 2 casesonly before therapy. AIP activity was determined by the level <strong>of</strong> serum markers, IgG andIgG4, and compared with findings <strong>of</strong> PET. In all 13 cases <strong>of</strong> AIP, a moderate to intense level<strong>of</strong> FDG accumulation was recognized in the pancreatic lesion before steroid therapy. Of 13patients, 11 (85 %) showed FDG accumulation in the multiple organs, such as mediastinal