68Ga-DOTATATE: Significance of Uptake in the Tail of the Pancreas in Patients Without Lesions.

PURPOSE: To measure the SUVs in the tail of the pancreas compared with normal liver parenchyma and somatostatin receptor-positive lesions. MATERIALS AND METHODS: Ga-DOTATATE PET/low mAs CT of 35 patients were reviewed. RESULTS: There was no significant difference (P = 0.59) between the SUVaverage of normal liver and the SUVpeak of normal tail. Five patients had uptake in the tail slightly above that of normal liver that were interpreted equivocally. In one of these patients with Ga-DOTATATE uptake in a peripancreatic lymph node, proven neuroendocrine tumor underwent a distal pancreatectomy and pathologic examination revealed islet cell hyperplasia. CONCLUSIONS: Ga-DOTATATE uptake in the tail of the pancreas above that of normal liver indicates a somatostatin receptor-avid lesion. Uptake in the tail of the pancreas equal to the liver can be normal. Patients with uptake equivalent to the liver should undergo further anatomical imaging before procedural intervention.

Lymphoma and Lactic Acidosis.

A 39-year-old man presented with new onset of sinus congestion, shortness of breath, and diaphoresis. His laboratory tests were notable for hypercalcemia and lactic acidosis. A CT scan of the head demonstrated mild paranasal disease. CT scan of the chest, abdomen, and pelvis demonstrated omental caking with lymphadenopathy and a thickened loop of bowel in the left upper quadrant suggestive of lymphoma. All abdominal lesions seen in the CT were intensely F-FDG avid with diffuse uptake in the bone marrow. There was markedly decreased F-FDG uptake in both the brain and liver. Histopathology was positive for Burkitt lymphoma.

Safety and Efficacy of 68Ga-DOTATATE PET/CT for Diagnosis, Staging, and Treatment Management of Neuroendocrine Tumors.

UNLABELLED: Our purpose was to evaluate the safety and efficacy of (68)Ga-DOTATATE PET/CT compared with (111)In-pentetreotide imaging for diagnosis, staging, and restaging of pulmonary and gastroenteropancreatic neuroendocrine tumors. METHODS: (68)Ga-DOTATATE PET/CT and (111)In-pentetreotide scans were obtained for 78 of 97 consecutively enrolled patients with known or suspected pulmonary or gastroenteropancreatic neuroendocrine tumors. Safety and toxicity were measured by comparing vital signs, serum chemistry values, or acquisition-related medical complications before and after (68)Ga-DOTATATE injection. Added value was determined by changes in treatment plan when (68)Ga-DOTATATE PET/CT results were added to all prior imaging, including (111)In-pentetreotide. Interobserver reproducibility of (68)Ga-DOTATATE PET/CT scan interpretation was measured between blinded and nonblinded interpreters. RESULTS: (68)Ga-DOTATATE PET/CT and (111)In-pentetreotide scans were significantly different in impact on treatment (P < 0.001). (68)Ga-DOTATATE PET/CT combined with CT or liver MRI changed care in 28 of 78 (36%) patients. Interobserver agreement between blinded and nonblinded interpreters was high. No participant had a trial-related event requiring treatment. Mild, transient events were tachycardia in 1, alanine transaminase elevation in 1, and hyperglycemia in 2 participants. No clinically significant arrhythmias occurred. (68)Ga-DOTATATE PET/CT correctly identified 3 patients for peptide-receptor radiotherapy incorrectly classified by (111)In-pentetreotide. CONCLUSION: (68)Ga-DOTATATE PET/CT was equivalent or superior to (111)In-pentetreotide imaging in all 78 patients. No adverse events requiring treatment were observed. (68)Ga-DOTATATE PET/CT changed treatment in 36% of participants. Given the lack of significant toxicity, lower radiation exposure, and improved accuracy compared with (111)In-pentetreotide, (68)Ga-DOTATATE imaging should be used instead of (111)In-pentetreotide imaging where available.

Cerebral lesions incidentally detected on 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography images of patients evaluated for body malignancies.

OBJECTIVES: The purpose of this work was done to evaluate the value of including the brain in the field of view of a whole-body 2-deoxy-2-[18F] fluoro-D-glucose positron emission tomography (FDG-PET) study of patients referred for the evaluation of body malignancies. METHODS: A total of 1026 consecutive patients were included in this work. The primary diagnoses were the following: lung (n = 253), colorectal (n = 148), head and neck (n = 61), lymphoma (n = 249), melanoma (n = 84), and others (n = 231). Whole-body FDG images including the brain were acquired with a dedicated PET tomograph (GE advance, General Electronic Medical Systems, Milwaukee, WI) one hour after the intravenous administration of 10 mCi of FDG. Two experienced nuclear medicine physicians interpreted the images. Positive findings in the brain or the skull were correlated with other imaging studies and clinical follow-up. RESULTS: Abnormal findings were detected in 3.9% (40/1026) of the patients. Among the 40 abnormal focal lesions, 29 patients had a known history of cerebral disease, cerebrovascular or metastatic disease in most patients. Of the 11 patients without a prior history of cerebral disease, four patients had increased focal FDG uptake suggestive of metastases. Among these, two were proven clinically, one was proven to be a skull base metastasis on MRI, and the other had negative clinical follow-up, but only of two months duration. The other seven patients had a decreased focal FDG uptake most consistent with infarct, one was proven clinically, and the other six had a negative clinical follow-up (mean of 6.3 months, range 1-10), but had multiple risk factors for cerebrovascular disease. CONCLUSIONS: We conclude that FDG-PET screening for cerebral lesions in patients with body malignancy has little clinical impact. Unsuspected cerebral or skull metastases were detected in 0.4% (4/1026) of the patients.