Determine the prevalence of benign indium-111 (111In) pentetreotide uptake in the pancreatic head and determine if a semi-quantitative method can be used to differentiate physiologic from pathologic uptake.
Institutional Review Board-approved, HIPAA-compliant retrospective review of 197 somatostatin receptor scintigraphy studies performed in 136 patients, from December 2012 to November 2013 at a large academic medical center. The pancreatic head uptake was visually graded and for all positive cases, two-dimensional and three-dimensional ratios of the pancreatic head to normal liver uptake were calculated. Statistical analysis using paired and two-sample t-tests was performed.
Nineteen of one hundred twenty-nine (14.7%) patients had benign 111In pentetreotide uptake in the pancreatic head. Seven of seven (100%) patients with neuroendocrine (NE) tumors had definite visual uptake. Uptake was 2.7× more likely benign than malignant. Using a three-dimensional region of interest (ROI) method, the pancreatic head-to-liver ratio was 0.91±0.38 (0.37–1.63) for benign uptake and 8.2±7.3 (1.79–23.6) for pathologic uptake (P<0.001). A threshold of 1.67 provided 100% accuracy for determining the presence or absence of a pancreatic head NE tumor. Using a two-dimensional ROI method, the uptake ratio was 0.88±0.37 (0.28–1.73) for benign and 7.5±6.2 (1.85–19.6) for pathologic uptake (P<0.001); a ratio threshold of 1.62 provided 97% accuracy. There was no difference between the uptake ratios at 4 and 24 h.
111In pentetreotide uptake in the pancreatic head is common and more frequently benign than malignant. Using simple ROI ratiometric methods helps to differentiate benign physiologic from malignant NE tumor uptake.
aMallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Missouri
bDepartment of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
Correspondence to Michael D. Farwell, MD, Department of Radiology, Hospital of the University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104, USA Tel: +1 215 662 7750; fax: +1 215 349 5843; e-mail: email@example.com
Received October 23, 2018
Received in revised form February 1, 2019
Accepted February 14, 2019