Fumitoshi Aga

Correlation of 18F-FLT Uptake with Tumor Grade and Ki-67 Immunohistochemistry in Patients with Newly Diagnosed and Recurrent Gliomas

We evaluated 3′-deoxy-3′-18F-fluorothymidine (18F-FLT) uptake in patients with newly diagnosed and recurrent gliomas and correlated the results with tumor grade and proliferative activity. Methods: 18F-FLT PET was investigated retrospectively in 56 patients, including 36 with newly diagnosed gliomas and 20 with recurrent gliomas. The standardized uptake values for tumor and normal contralateral hemisphere were calculated, and the tumor-to-normal (T/N) ratio was determined. Tumor grading and proliferative activity were estimated in tissue specimens. Results: There was a significant difference in T/N ratio among different grades of newly diagnosed gliomas and between low- and high-grade newly diagnosed and recurrent gliomas. 18F-FLT uptake correlated more strongly with the proliferative activity in newly diagnosed gliomas than in recurrent gliomas. Conclusion: 18F-FLT PET seems to be useful in the noninvasive assessment of grade and proliferation in gliomas, especially newly diagnosed gliomas.

Hypoxia assessed by 18F-fluoromisonidazole positron emission tomography in newly diagnosed gliomas:

Objective The aim of this study was to evaluate the degree of hypoxia in newly diagnosed gliomas using 18F-fluoromisonidazole (FMISO) PET and to compare the results with tumor grade. Methods A total of 30 patients with newly diagnosed gliomas were examined using FMISO PET. Grading of the tumor was performed according to the WHO classification. The FMISO PET images were scaled to the venous blood concentration of FMISO activity to produce tumor-to-blood (T/B) values. Hypoxia was defined as a region with a T/B ratio of at least 1.2, and the maximum T/B (T/Bmax) value was calculated by region-of-interest analysis. Results There was a correlation between FMISO uptake and glioma grade, with all low-grade gliomas (grades I and II) demonstrating no hypoxia and all high-grade gliomas (grades III and IV) showing hypoxia. The mean T/Bmax in grade IV gliomas was significantly higher than that in grade III gliomas (P<0.02). Conclusion FMISO PET is a potential tracer in the assessment of noninvasive tumor grading in newly diagnosed gliomas.

Hypertrophic cranial pachymeningitis with IgG4-positive plasma cells detected by C-11 methionine PET.

A 53-year-old man who presented with mild headache and ophthalmodynia underwent carbon-11 methionine (MET) positron emission tomography (PET). MET PET images demonstrated intense uptake in the periphery of the brain, significantly higher than the physiological uptake in the brain. Biopsy specimens f

A case of primary pericardial mesothelioma detected by 18F-FDG PET/CT.

Primary pericardial mesothelioma is an extremely rare malignancy. We report a case of a 58-year-old woman who presented with fever and fatigue. She had no apparent history of occupational or incidental exposure to asbestos. A postcontrast-enhanced chest CT revealed a 77 × 56-mm mass lesion in the pericardium. The FDG PET/CT was carried out, which demonstrated an intense FDG uptake to a main pericardial tumor and disseminated lesions in the pericardium. Histologic examination confirmed the primary malignant pericardial mesothelioma.

SPECT/CT imaging in ulnocarpal impaction syndrome.

We report a 42-year-old man who presented with ulnar-sided wrist pain. MR image revealed bone marrow edema in the lunate bone. Ulnocarpal impaction syndrome was diagnosed by MRI and arthrography. Bone scintigraphy showed increased uptake in the wrist. SPECT/CT with 2- and 3-dimensional reconstruction images clearly demonstrated abnormal accumulation on the ulnar side of the lunate bone.

SPET/CT imaging in radionuclide cisternography to detect cerebrospinal fluid leakage in spontaneous intracranial hypotension associated with SLE

Spontaneous intracranial hypotension (SIH) is typically characterized by orthostatic headache. The most frequent underlying pathogenic mechanism is cerebrospinal fluid (CSF) leakage. It has been suggested that dural structural weakness in some connective tissue diseases may lead to dural tears and diverticula and consequently leakage [1, 2]. We present a case of SIH associated with systemic lupus erythematosus. A 63-year-old woman with a 1-year history of postural headaches was admitted. Precontrast brain MRI revealed bilateral subdural haematoma, and postcontrast brain MRI showed diffuse pachymeningeal thickening and enhancement. Radionuclide cisternography 1 h after intrathecal injection of In-DTPA showed early visualization of the kidneys and bladder (a). Accumulation of radioactivity in the area outside the subarachnoid space at the level of the cervicothoracic junction bilaterally was also noted (a). SPET/CT two-dimensional transaxial (b) and coronal (c) images and the three-dimensional reconstructed image (d) clearly showed the CSF leak expanding into the bilateral paraspinal soft tissues. Radionuclide cisternography has been used extensively in the evaluation of SIH. Typical indirect findings include early visualization of the tracer in the kidneys and bladder, slow ascent along the spinal axis, and a paucity of activity over the cerebral convexities. However, it is known that there are many false-negative or unclear findings with radionuclide cisternography. Furthermore, direct delineation of the CSF leak remains obscure in as many as one-third of patients [3]. Integrated SPET/CT imaging can improve the precise localization of the radioisotope leak even if planar radionuclide cisternography shows poor spatial resolution.

18F-FDG PET/CT imaging of extensive systemic sarcoidosis with epididymal involvement.

Sarcoidosis rarely involves the male reproductive tract. We present an unusual case of extensive systemic sarcoidosis with epididymal involvement. The ¹⁸F-FDG PET/CT demonstrated extensive foci of hypermetabolic activity involving multiple lymph nodes, liver, epididymides, muscles, and subcutaneous tissues. After immunosuppressive therapy, a follow-up PET scan showed almost complete disappearance of the FDG accumulation except for in the hilar lymph nodes.

SPECT/CT imaging in 99mTc-PMT hepatobiliary scintigraphy to detect bone metastases from hepatocellular carcinoma.

We report a 62-year-old man who presented with pain on the right side of his hip. CT revealed destructive masses in the right femur and left ilium. Histological examination indicated metastases from hepatocellular carcinoma, and further investigations revealed the primary tumor in the liver. Hepatobiliary scintigraphy using 99mTc N-pyrydoxyl-5-methyltryptophan and fused SPECT/CT clearly showed abnormal accumulation in these bone metastases from hepatocellular carcinoma.