Ken Herrmann, Presenter: Nothing to Disclose

Mert Erkan, Abstract Co-Author: Nothing to Disclose

Tibor Schuster, Abstract Co-Author: Nothing to Disclose

Martin Dobritz MD, Abstract Co-Author: Nothing to Disclose

Andreas K. Buck MD, Abstract Co-Author: Nothing to Disclose

Roland Schmid MD, Abstract Co-Author: Nothing to Disclose

Differentiation of pancreatic masses remains difficult for all available imaging modalities. Therefore, we tested the diagnostic accuracy of FLT-PET and FDG-PET/CT in patients with suspected pancreatic masses scheduled to undergo surgery.

46 patients (pts) with pancreatic tumors suspicious for malignancy and scheduled resective surgery have been recruited for this study (1 pt was excluded with leiomyosarcoma and 1 pt after withdrawal of consent; 3 pts did not undergo either FLT-PET or FDG-PET/CT due to logistic reasons). In 41 pts FLT-PET and FDG-PET/CT scans were performed, a diagnostic CT was available in 31 pts. FLT-PET (45 min p.i., 300 MBq FLT; ECAT HR+) and FDG-PET/CT (60-90 min p.i., 340 MBq FDG; Biograph Sensation 16 PET/CT) emission images were acquired according to standard protocols. Tracer uptake in the tumor (FDG- and FLT-SUV) was quantified by region of interest (ROI) technique. For FDG-PET/CT analysis, correct ROI placement was ensured via side-by-side reading of corresponding CT images.

In the 41 pts histology revealed malignant disease in 33 and benign lesions in 8 pts. Visual analysis of FDG-PET and FLT-PET resulted in sensitivity values of 91% (30/33) and 70% (23/33), respectively. Corresponding specificities were 50% (4/8) for FDG-PET and 75% (6/8) for FLT-PET. In the subgroup of 39 patients with FDG-PET/CT, histology revealed malignant disease in 31 and benign lesions in 8 pts. Evaluation of PET/CT (ceCT available in 31 pts) resulted in a sensitivity of 97% (30/31) and a specificity of 25% (2/8). Mean FLT-uptake in all malignant tumors was 3.0 (range, 1.1-6.5; mean FDG-SUV: 5.1, range, 2.1-12.7; p<0.001).

For differentiation of pancreatic tumors, FDG-PET and FDG-PET/CT showed a higher sensitivity but lower specificity than FLT-PET. Interestingly, visual analysis of FLT-PET led to two false positive findings. Due to the limited number of investigated patients so far, the clinical value of adding FLT-PET to the diagnostic workup of pancreatic tumors remains to be determined.

Staging of pancreatic masses remains difficult in clinical routine. Due to its high specificity imaging of proliferation with FLT-PET potentially improves differentiation of pancratic tumors.

Herrmann, K, Erkan, M, Schuster, T, Dobritz, M, Buck, A, Schmid, R, Comparison of 3'-deoxy-3'-[18F]fluorothymidine Positron Emission Tomography (FLT-PET) and FDG-PET/CT for the Detection of Pancreatic Cancer.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9010087.html