Toshiyuki Okumura

Extrapancreatic F-18 FDG accumulation in autoimmune pancreatitis.

We report two cases of autoimmune pancreatitis (AIP) in which fluorine-18 fluorodeoxyglucose (FDG) showed moderate accumulation in the pancreas, as well as in bilateral submandibular glands and in multifocal lymph nodes. FDG positron emission tomography (PET)/computed tomography (CT) is a useful diagnostic tool to assess the extrapancreatic lesions of AIP, which is a recently proposed new clinicopathological entity named immunoglobulin G4 (IgG4)-related systemic disease. Recognition of the FDG-PET/CT findings of IgG4-related sclerosing disease is crucial to avoid unnecessary surgery or other intervention because of similarities to malignant lymphoma or malignant tumor with multiple lymph node metastases.

Usefulness of FDG-PET/CT in the detection of pancreatic metastases from lung cancer

ObjectiveThe objective of this study was to assess the ability to detect pancreatic metastasis of lung cancer and to clarify the degree of fluorodeoxyglucose (FDG) accumulation and computed tomography (CT) characteristics of pancreatic metastasis from lung cancer.MethodsA total of 573 patients (415 men and 158 women) with lung cancer were retrospectively evaluated. All patients underwent FDG-positron emission tomography (PET)/CT with contrast-enhanced CT for first=stage (313 patients; initial study group) or follow-up study (260 patients; follow-up study group). A lesion was regarded as positive for metastasis on the basis of visual judgment of the degree of increased metabolism by two experienced and independent interpreters, supported by semiquantitative evaluation on the basis of calculation of the maximum standardized uptake value (SUVmax).ResultsAbnormal accumulations in the pancreas were detected in 5 of 313 patients (1.60%) in the initial study group, and 6 of 260 patients (2.31%) in the follow-up study group. Seven of these patients had adenocarcinoma, three had small cell carcinoma, and the rest had large cell endocrine carcinoma. Tumor sizes (longitudinal diameter), measured by CT, of these 11 patients ranged from 6 mm to 52 mm (mean ± SD 8.3 mm ± 11.9 mm), and SUVmax for 1 h ranged from 3.37 to 11.1 (mean ± SD 6.12 ± 2.43). Three of these pancreatic lesions were difficult to determine by routine transaxial images, and detection was obvious only by thin-slice images or multiplanar reconstruction images. Contrast-enhanced CT showed gradual fill-in from the peripheral portion to the center. In addition, 10 of 11 cases did not show main pancreatic duct dilatation even if the tumor size was large.ConclusionsMetastases to the pancreas in lung cancer patients are not so rare and radiologists first have an important role to detect the pancreatic mass and then suggest to metastasis as the likely diagnosis. For this purpose, FDG-PET/CT has an advantage in depicting unsuspected pancreatic metastasis from lung cancer, particularly that which is not detected by CT alone.

FDG PET/CT findings of thymic carcinoid and bronchial carcinoid in a patient with multiple neuroendocrine neoplasia type1.

Thymic carcinoid is a rare thymic neoplasm and frequently accompanies neuroendocrine neoplasia (MEN) type1. Other carcinoid tumors derived from the foregut, like bronchial, gastric, and duodenal carcinoid are also of high incidence in MEN type1 patients. Recent studies revealed thymic carcinoid as a FDG-avid tumor, and FDG-PET is useful in detecting thymic carcinoid, its metastases, and recurrence. On the other hand, FDG accumulation in bronchial carcinoid is variable. We report a case of thymic carcinoid and bronchial carcinoid in a patient who was diagnosed as having multiple neuroendocrine neoplasia type1 previously. FDG PET/CT showed abnormal accumulation in the thymic atypical carcinoid and its mediastinal lymph node metastases, whereas the FDG did not show uptake in the typical bronchial carcinoid. These findings indicate that FDG PET is useful in detecting thymic carcinoid and its metastases.

High F-18 fluorodeoxyglucose accumulation in solid pseudo-papillary tumors of the pancreas

We report two cases of young women with a solid pseudo-papillary tumor of the pancreas which having cystic and hemorrhagic components with marked calcification on computed tomography and magnetic resonance imaging. F-18 fluorodeoxyglucose positron emission tomography revealed abnormally increased accumulation of F-18 fluorodeoxyglucose in the pancreas tail tumors, especially in the non-calcified solid portion of the tumors. These patients underwent elective resection of the masses and distal pancreatectomy and were diagnosed with solid pseudo-papillary tumors by histopathological analysis. There was no evidence of distant metastasis on follow-up after surgery and they showed no histopathological findings suggesting malignancy. These cases suggest that solid pseudo-papillary tumor may show high uptake of F-18 fluorodeoxyglucose.

FDG PET/CT findings of splenic angiosarcoma.

Abstract:A case of splenic angiosarcoma is described with FDG PET findings. The patient was 53-year-old male had epigastric pain and weight loss. FDG PET/CT revealed a solitary splenic tumor of 140 mm invading the liver and left diaphragm. FDG accumulated in the periphery of the tumor. Five months a

Very-high-flow injection rate for upper abdominal CT angiography

Background. The purpose of this study was to compare a very-high-flow injection-rate method (group A) and a conventional injection-rate method (group B) for visualization of upper abdominal arteries by multidetector helical computed tomography (MDHCT).Methods. The subjects were 240 patients suspected to have abdominal lesions. They were randomly assigned to group A (120 patients) and group B (120 patients). In group A, the bilateral medial cubital veins were punctured, and contrast medium was infused at a rate of 8.6–9.6ml/s. In group B, the unilateral medial cubital vein was punctured, and contrast medium was infused at a rate of 2.0–3.0ml/s. The quality of vascular visualization was graded as poor, good, or excellent by three radiologists.Results. All visualizations of the celiac trunk (CE) and superior mesenteric artery (SMA) were graded as excellent in both group A and group B. Visualization grades of the subsegmental branches of the hepatic artery (HA), right gastric artery (RGA), cystic artery, dorsal pancreatic artery (DPA), and superior pancreaticoduodenal artery (SPDA) were good or excellent in 75% (paging method)/53.3% (three-dimensional method), 85%/30%, 77.7%/18.3%, 76.7%/28.3%, and 88.3%/42.5%, respectively, in group A, and 33.3%/ 11.7%, 46.7%/3.4%, 41.6%/5%, 55%/4.2%, and 72.5%/ 14.2%, respectively, in group B. The appearance rate of intrahepatic portal branches was 28.3% in group A and 66.7% in group B in the arterial dominant phase.Conclusion. Group A showed better visualization results than Group B in upper abdominal arteries according to MDHCT.