18F-fluorodeoxyglucose positron emission tomography features of idiopathic retroperitoneal fibrosis.

OBJECTIVE: To evaluate the 18F-fluorodeoxyglucose (FDG) uptake features of idiopathic retroperitoneal fibrosis (IRF). METHODS: 18F-Fluorodeoxyglucose positron emission tomographic (PET) or PET/computed tomographic findings were retrospectively reviewed in 6 patients with IRF. FDG PET or PET/computed tomography was performed 1 and 2 hours after FDG injection. The FDG level was scored using a 4-point scale, and the intensity of FDG uptake was quantified using the maximum standardized uptake value (SUVmax). RESULTS: In the 1-hours images, intense FDG uptake by IRF was observed in 5 patients before steroid treatment, but no abnormal uptake was noted in 1 patient receiving steroid treatment. The SUVmax in IRF increased from a mean +/- SD of 6.0 +/- 1.2 (range, 4.9-7.6) to 7.6 +/- 1.1 (range, 5.9-8.2) for all 4 patients who underwent 1 and 2 hours dual-time point imaging. Abnormal uptake was also noted in the mediastinum and the pancreas in 1 and 2 patients, and the diagnoses of mediastinal fibrosis and autoimmune pancreatitis were made, respectively. The SUVmax was stable or increased in the 3 lesions of mediastinal fibrosis and autoimmune pancreatitis. CONCLUSION: FDG PET may be a reliable means of evaluating disease activity and the extent of IRF, but dual-time point imaging may not be useful to differentiate malignancy from IRF.

FDG PET findings of chronic myeloid leukemia in the chronic phase before and after treatment.

We report 2 patients with chronic myeloid leukemia in the chronic phase showing diffusely increased F-18 fluorodeoxyglucose (FDG) uptake in the bone marrow before treatment. Follow-up FDG positron emission tomography (PET) scans were performed in a patient after cessation of treatment and in the other under treatment. Both FDG PET findings showed reduced FDG uptake in the bone marrow. A series of these FDG PET findings suggest the usefulness of FDG PET for the diagnosis and monitoring of chronic myeloid leukemia after treatment.

The efficacy of whole-body FDG-PET or PET/CT for autoimmune pancreatitis and associated extrapancreatic autoimmune lesions.

PURPOSE: The aim of this study was to evaluate retrospectively the efficacy of whole-body (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) for autoimmune pancreatitis (AIP) and associated extrapancreatic autoimmune lesions. METHODS: Whole-body FDG-PET or PET/computed tomography (CT) findings were reviewed in six patients with AIP. The initial PET scans were performed 1 h and 2 h after FDG injection in all six patients. Follow-up PET scans were performed during or following steroid therapy in five patients and in one patient who did not have steroid therapy. RESULTS: The initial PET scans revealed intense FDG uptake by AIP in all six patients. The maximum standardized uptake value (SUVmax) increased in four patients and was stable in two patients. The intense uptake in the pancreas disappeared during or following steroid therapy in five patients and in one patient who showed spontaneous remission of AIP. Abnormal FDG uptake by extrapancreatic autoimmune diseases was observed in five of the six patients: sclerosing sialadenitis (n = 5), lymphadenopathy (n = 5), retroperitoneal fibrosis (n = 2), interstitial nephritis (n = 2) and sclerosing cholecystitis (n = 1). Abnormal FDG uptake disappeared in the salivary glands (n = 4), lymph nodes (n = 4), retroperitoneum (n = 2), kidneys (n = 1) and gallbladder (n = 1) during or following steroid therapy and remained in the salivary glands and lymph nodes of a spontaneous remission patient. CONCLUSION: These results suggest that whole-body FDG-PET may be useful for detecting AIP and associated extrapancreatic autoimmune lesions and for monitoring their disease activity but that dual time point imaging may not be useful for differentiating malignancy from AIP.

FDG PET and PET/CT monitoring of autoimmune pancreatitis associated with extrapancreatic autoimmune disease.

We report a series of FDG PET findings of a 69-year-old male patient with autoimmune pancreatitis (AIP) associated with extrapancreatic disease. The first FDG PET revealed diffuse uptake of FDG in AIP and retroperitoneal fibrosis (RF). The second FDG PET after cessation of steroid treatment indicated subsiding of disease activity in AIP, continuous disease activity in RF, and new extrapancreatic lesions, including enlargement of a right salivary gland, nephritis, and lymphadenopathy. The last FDG PET under steroid treatment revealed reduced FDG uptake in the above abnormal FDG uptake lesions. A series of these FDG PET findings suggest the usefulness of FDG PET for the diagnosis and monitoring of AIP associated with extrapancreatic autoimmune diseases.

18F-FDG PET/CT findings of a right subphrenic foreign-body granuloma.

We report a case of an 85-year-old woman with a foreign-body granuloma which accumulated 18F-fluorodeoxyglucose (FDG). Unenhanced computed tomography showed a hyperdense mass with a hypodense rim in the right subphrenic space. FDG PET/CT images showed intense FDG uptake in the hypodense rim and little FDG uptake in the center of the mass, showing a ring-shaped appearance. The fusion imaging of FDG PET/CT represented the metabolic features of the foreign-body granuloma. When a ring-shaped FDG uptake is noted in the abdomen of a patient with a history of abdominal surgery, a foreign-body granuloma should be included in the differential diagnosis.