Katsuhiko Kato MD, Presenter: Nothing to Disclose

Shinji Abe RT, Abstract Co-Author: Nothing to Disclose

Mitsuru Ikeda MD, Abstract Co-Author: Nothing to Disclose

Shigeki Itoh, Abstract Co-Author: Nothing to Disclose

Kazuhiro Shimamoto MD, PhD, Abstract Co-Author: Nothing to Disclose

Shinji Naganawa MD, Abstract Co-Author: Nothing to Disclose

It has been thought that FDG-PET is useful for the differential diagnosis between pancreatic cancer and mass-forming pancreatitis. In practice, however, there are many obscure points about this problem. The present study was undertaken to clarify the usefulness of FDG PET/CT and MRI for the differential diagnosis between them.

32 patients with suspected pancreatic tumors were examined by FDG-PET/CT. 19 of these 32 study patients were finally diagnosed as pancreatic cancer and the other 13 were pancreatitis. A region of interest (ROI) was drawn on the areas of pancreatic tumors, and the mean and maximal standardized uptake values (SUVs) within this ROI were determined 1 hr and additionally 2 hrs in most cases after injection of FDG. 10 of 32 patients were also examined by MRI and ADC values were determined at lesions.

The mean and maximal SUVs in the early phase (1 hr) for pancreatic cancer were 2.83-8.11 (mean:4.90) and 3.37-10.16 (6.83), respectively. Those for pancreatitis were 1.97-4.71 (3.35) and 2.59-5.37 (4.50), respectively. The mean and maximal SUVs in the delayed phase (2 hrs) for pancreatic cancer were 3.11-6.49 (mean: 5.57) and 3.59-11.48 (7.60), respectively. Those for pancreatitis were 1.47-4.58 (3.92) and 2.0-9.98 (5.51), respectively. The differences in the mean and maximal SUVs in the early phase between pancreatic cancer and pancreatitis were statistically significant (p<0.05). In all cases of pancreatic cancer and most cases of pancreatitis, SUVs at 2hrs were higher than at 1 hr. But the degree of their elevation in pancreatic cancer did not differ significantly from that in pancreatitis. ADC values for pancreatic cancer were 1.29 and for pancreatitis were 1.40. The differences in ADC values between pancreatic cancer and pancreatitis were statistically not significant.

It is possible to achieve the differential diagnosis between pancteatic cancer and mass-forming pancreatitis by comparing the heights of SUVs in FDG PET/CT in the early phase. But it is difficult to achieve the differential diagnosis between pancreatic cancer and pancreatitis by comparing the time course of SUVs in the early and delayed phase in FDG PET/CT and ADC values in MRI.

FDG PET/CT shows a limited efficacy for differentiating pancreatic cancer from mass-forming pancreatitis and their images should be cautiously evaluated for differentiating both diseases.

Kato, K, Abe, S, Ikeda, M, Itoh, S, Shimamoto, K, Naganawa, S, F-18 FDG PET/CT in Pancreatic Tumors: Is the Differential Diagnosis between Pancreatic Cancer and Mass-forming Pancreatitis Possible?.  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8007144.html