Planar scintigraphy using Tc-99mpertechnetate is useful for snapshot evaluation of hot thyroid nodules, which are pathologically follicular adenoma and seldom, if ever, malignant. The autonomy of the hot nodules has been demonstrated by the presence of thyroid-stimulating hormone-dependent extra-nodular thyroid tissue besides the hot nodules. Here, we present two cases of hot thyroid nodules in patients who underwent quantitative single-photon emission computed tomography/computed tomography (SPECT/CT). In addition to the nodules, contralateral normal thyroid parenchyma was evaluated based on standardized uptake values. One patient had a traditional follicular adenoma suppressing other thyroid tissue, whereas the other patient seemed to have a nodule erupting from underlying hyperfunctioning, not suppressed, thyroid tissue. This novel approach using quantitative SPECT/CT unveils a new pathology of hot thyroid nodule that does not suppress, but coincides with hyperfunctioning thyroid tissue.
Adenoma ; Humans ; Pathology ; Radionuclide Imaging ; Sodium Pertechnetate Tc 99m ; Thyroid Gland ; Thyroid Nodule

No abstract available.
Adosterol/diagnostic use ; Adrenal Cortex/radiography/*radionuclide imaging ; Adrenal Cortex Neoplasms/pathology/radiography/*radionuclide imaging/surgery ; Adrenalectomy/methods ; Adrenocortical Adenoma/pathology/radiography/*radionuclide imaging/surgery ; Aged ; Aldosterone/blood ; Blood Specimen Collection/methods ; Humans ; Hyperaldosteronism/radiography/*radionuclide imaging ; Male ; Radiopharmaceuticals/diagnostic use ; Tomography, X-Ray Computed

BACKGROUND/AIMS: Incidentally detected focal 18F-fluorodeoxyglucose (FDG) uptake was compared with colonoscopy. We investigated the characteristics of colon adenomas which were revealed on PET/CT. Then we identified whether additional colonoscopy was necessary in patients with lesions which were revealed on PET/CT but had no matched lesions on colonoscopy. METHODS: We retrospectively reviewed 95 patients who underwent colonoscopy within a 6 month interval after they had focal FDG uptake from January 2010 to May 2012 at National Police Hospital in Korea. Also, we analyzed 30 patients who underwent additional colonoscopy within 2 years after they had no matched lesions on primary colonoscopy. RESULTS: PET/CT depicted 54.6% (41/75) of adenomas and adenocarcinomas. The PET visibility of colon adenoma was significantly associated with degree of dysplasia (p=0.027), histologic type (p=0.040), and the size (p=0.038). The positivity rate was increased with higher degree of dysplasia (low-grade dysplasia, 47%; high-grade dysplasia, 78%; adenocarcinoma, 100%) and villous patterns of histologic type (tubular, 46.8%; tubulovillous, 87.5%; villous, 100%). Patients with adenomas larger than 10 mm (87.5%) had higher detection rate compared to those with adenomas smaller than 10 mm (49.0%). Among the 30 patients who underwent additional colonoscopy, only one patient had a 6 mm sized tubular adenoma (low-grade dysplasia). CONCLUSIONS: Incidental focal colonic uptake may indicate advanced adenoma or adenocarcinoma. Thus, it justifies performing colonoscopy for identifying the presence of colon neoplasms. However, in case of unmatched lesions between PET/CT and colonoscopy, there was little evidence that additional colonoscopy would yield benefits.
Adenocarcinoma/pathology/radiography/radionuclide imaging ; Adenoma/pathology/radiography/radionuclide imaging ; Adult ; Aged ; Colonic Neoplasms/pathology/*radiography/*radionuclide imaging ; Colonic Polyps/pathology ; Colonoscopy ; Female ; Fluorodeoxyglucose F18/diagnostic use ; Humans ; Male ; Middle Aged ; Multimodal Imaging ; Positron-Emission Tomography ; Radiopharmaceuticals/diagnostic use ; Retrospective Studies ; Tomography, X-Ray Computed

BACKGROUND/AIMS: Although magnetic resonance imaging (MRI) is a good visual modality for the evaluation of pituitary lesions, it has limited value in the diagnosis of mixed nodules and some cystic lesions. We evaluated the usefulness of 18F-fluorodeoxyglucose positron emission tomography (FDG PET) for patients with pituitary lesions. METHODS: 18F-FDG PET and MRI were performed simultaneously in 32 consecutive patients with pituitary lesions. The relationships between FDG uptake patterns in PET and MRI findings were analyzed. RESULTS: Of 24 patients with piuitary adenomas, 19 (79.2%) showed increased uptake of 18F-FDG in the pituitary gland on PET scans. All patients with pituitary macroadenomas showed increased 18F-FDG uptake on PET scans. Meanwhile, only five (50%) of the 10 patients with pituitary microadenomas showed positive PET scans. Interestingly, of two patients with no abnormal MRI findings, one showed increased 18F-FDG uptake on PET. For positive 18F-FDG uptake, maximum standardized uptake values (SUVmax) > 2.4 had 94.7% sensitivity and 100% specificity. In addition, SUVmax increased in proportion to the size of pituitary adenomas. Most cystic lesions did not show 18F-FDG uptake on PET scans. CONCLUSIONS: About 80% of pituitary adenomas showed positivity on PET scans, and SUVmax was related to the size of the adenomas. PET may be used as an ancillary tool for detection and differentiation of pituitary lesions.
Adenoma/pathology/*radionuclide imaging ; Adolescent ; Adult ; Aged ; Aged, 80 and over ; Female ; Fluorodeoxyglucose F18/*diagnostic use ; Humans ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Pituitary Gland/pathology/*radionuclide imaging ; Pituitary Neoplasms/pathology/*radionuclide imaging ; *Positron-Emission Tomography ; Predictive Value of Tests ; Radiopharmaceuticals/*diagnostic use ; Tumor Burden ; Young Adult