Brain PET Imaging of 11C-Methionine, 18F-FDG, and 18F-THK5351 in a Case of Lymphomatoid Granulomatosis.

ABSTRACT: A 52-year-old woman complained of upper respiratory symptoms and subsequently developed Wallenberg syndrome. Chest CT and brain MRI revealed multiple nodular lesions in the lungs and brain. She was pathologically diagnosed with low-grade lymphomatoid granulomatosis by lung biopsy. Brain PET examinations using 11C-methionine, 18F-FDG, and 18F-THK5351 were performed. Uptake of 11C-methionine and 18F-FDG was slightly increased in some lesions, likely reflecting the degree of inflammatory cell infiltration. 18F-THK5351 uptake was significantly increased in all lesions, likely reflecting the degree of reactive astrogliosis. This case illustrates the utility of PET studies for diagnosing lymphomatoid granulomatosis and provides insight into its pathophysiology.

Factors affecting radiation exposure dose in nursing staff during (18)F-fluorodeoxyglucose positron emission tomography/computed tomography.

OBJECTIVES: We evaluated factors associated with increased radiation exposure dose in nursing staff who assisted patients with (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET)/computed tomography (CT) examinations. METHODS: The Barthel Index and Mini-Mental State Examination (MMSE) score were obtained before PET/CT examinations in 193 patients (mean age ± SD, 77.7 ± 8.0 yr). Three nurses self-measured their radiation exposure dose while assisting patients during each PET examination. Disturbance factors during PET examinations (use of a stretcher or wheelchair, use of lines or tubes connected to the patient, use of diapers or urethral catheterization, patient age), (18)F-FDG injection dose, and previous PET/CT experience in the patients and outpatient or inpatient status were evaluated as factors possibly associated with increased radiation exposure. Principle component analysis, univariate analysis, and multivariate regression analysis were used for assessing associations between radiation exposure dose and factors. RESULTS: The mean radiation exposure dose of the nursing staff was 6.07 ± 5.71 µSv per examination. Statistically significant factors associated with increased radiation exposure (<8 or ≥8 µSv/case) in the univariate analysis were the Barthel Index (<75 or ≥75), MMSE score (<22 or ≥22) of the patients, numbers of lines or tubes to the patient, use of a stretcher or wheelchair, and (18)F-FDG injection dose. Multivariate logistic regression modeling showed that the Barthel Index (<75 or ≥75) and MMSE score (<22 or ≥22) of the patients were significant factors in the final model. CONCLUSIONS: Lower Barthel Indexes (lower ADL) and lower MMSE scores (lower cognitive function) were independent factors associated with increased radiation exposure dose in nursing staff assisting during (18)F-FDG PET/CT.

Cerebral glucose metabolism in the striate cortex positively correlates with fractional anisotropy values of the optic radiation in patients with glaucoma.

BACKGROUND: It has recently become clear that glaucoma is not only an ocular disease, but involves central visual pathways as well. The purpose of this study was to examine functional and structural alterations in the brains of glaucoma patients. DESIGN: Case-control study in a hospital. PARTICIPANTS: A total of 32 glaucoma patients and 19 healthy controls. METHODS: All participants underwent positron emission tomography with (18)F-fluorodeoxyglucose, diffusion-tensor magnetic resonance imaging, and the 30-2 program of the Humphrey Visual Field Analyzer. MAIN OUTCOME MEASURES: Fractional anisotropy values of the optic radiation were compared between the two groups by defining regions of interests. Cerebral glucose metabolism was compared using statistical parametric mapping software. The correlation coefficients were calculated between the average of the total deviation of hemivisual fields of both eyes, fractional anisotropy values of the contralateral optic radiation and glucose metabolism in the contralateral striate cortex. RESULTS: Fractional anisotropy values in the bilateral optic radiations were significantly lower in patients with glaucoma. A significant glucose hypometabolism in the bilateral striate cortex was also observed in the glaucoma group. Regression analyses for glaucoma patients demonstrated that the average of the total deviation of hemivisual fields significantly correlated with both fractional anisotropy value of the contralateral optic radiation and glucose metabolism in the contralateral striate cortex. Moreover, there were significant correlations between fractional anisotropy values of the optic radiation and ipsilateral striatal glucose metabolism. CONCLUSION: We observed structural alterations in the bilateral optic radiations and glucose hypometabolism in the bilateral striate cortex of glaucoma patients.

¹¹C-PiB PET imaging of encephalopathy associated with cerebral amyloid angiopathy.

We herein report that the clinical, laboratory, and radiographic features and positron emission tomography (PET) imaging may provide valuable clues to the pathogenesis of cerebral amyloid angiopathy (CAA)-associated encephalopathy, which currently remains unclear. We herein describe two cases of encephalopathy with CAA, with an emphasis on PET imaging with (11)C-Pittsburgh compound B ((11)C-PiB) and (18)F-fluorodeoxyglucose ((18)F-FDG). One case of Alzheimer's disease for which a brain biopsy was performed showed CAA-related inflammation. Another case that had developed sudden sensory aphasia presented with posterior reversible encephalopathy syndrome-like vasogenic edema in the left temporal region with (11)C-PiB uptake and microhemorrhages. (11)C-PiB and (18)F-FDG PET are useful for detecting CAA-associated encephalopathy, including atypical CAA cases.

Positive correlation between the degree of visual field defect and optic radiation damage in glaucoma patients.

PURPOSE: We evaluated optic radiation (OR) damage in patients with glaucoma by using fractional anisotropy (FA) of diffusion-tensor magnetic resonance imaging. METHODS: We studied 29 patients with glaucoma and 19 healthy controls. Regions of interest were placed over the bilateral anterior and posterior ORs on the FA maps, and the FA value of each region was measured. RESULTS: FA values of the bilateral anterior and posterior ORs were significantly lower in patients with glaucoma (anterior right, P = 0.0002; anterior left, P = 0.00028; posterior right, P = 0.0004; and posterior left, P = 0.0001) than in the healthy controls. In glaucoma patients, significant correlations were observed between the FA values and the average of the total deviation of the contralateral hemifields of both eyes (left hemifield and anterior right OR, correlation coefficient [r] = 0.46 [P = 0.013]; right hemifield and anterior left OR, r = 0.43 [P = 0.021]; left hemifield and posterior right OR, r = 0.54 [P = 0.0027]; and right hemifield and posterior left OR, r = 0.46 [P = 0.012]). CONCLUSIONS: FA values of the entire OR were decreased in glaucoma patients and correlated with the degree of visual field defect.

The association of the expression of vascular endothelial growth factor with the cystic component and haemorrhage in pituitary adenoma.

Vascular endothelial growth factor (VEGF) is known to be a mediator of angiogenesis and vascular permeability. A cystic component and haemorrhage are often found in pituitary adenomas. We assessed the VEGF expression based on immunohistochemical examinations in 48 pituitary adenomas. All the adenomas showed some VEGF immunoreactivity mainly in the cytoplasm of tumour cells. Of the 48 adenoma-cases, 16 cases had a strong VEGF immunoreactivity, 26 cases had a moderate one, and 6 cases had a weak one. On the MR images, a cystic component was found in 16 cases (33.3%), and a haemorrhage was found in 18 cases (37.5%). The VEGF immunoreactivity had a significant relationship with the cystic component but not the haemorrhage, size, recurrence, or HE classification. These findings suggest that VEGF plays any potential role in the pathogenesis of cystic formation in pituitary adenomas.

Intracranial meningeal involvement in Churg-Strauss syndrome.

We describe the case of a 54-year-old woman with a clinical diagnosis of Churg-Strauss syndrome (CSS). The patient had a fever of unknown origin, severe headache, progressing left ophthalmoplegia, and visual acuity disturbance. MR imaging revealed diffuse and thick hypointense lesions on T2-weighted images in the frontal meninges and anterior falx cerebri with diffuse enhancement. Similar lesions were also detected in the left superior ophthalmic fissure to the cavernous sinus. Nodular lesions in the fourth ventricle, which might have been the cause of hydrocephalus, were hypointense on T2-weighted images. These MR imaging findings suggested remote granulomatous involvement in the meninges and choroid plexus associated with CSS. To our knowledge, remote meningeal involvement in association with CSS has not been previously reported.