Chisa Hosokawa

Clinical application of 3D arterial spin-labeled brain perfusion imaging for Alzheimer disease: comparison with brain perfusion SPECT.

BACKGROUND AND PURPOSE: Alzheimer disease is the most common neurodegenerative disorder with dementia, and a practical and economic biomarker for diagnosis of Alzheimer disease is needed. Three-dimensional arterial spin-labeling, with its high signal-to-noise ratio, enables measurement of cerebral blood flow precisely without any extrinsic tracers. We evaluated the performance of 3D arterial spin-labeling compared with SPECT, and demonstrated the 3D arterial spin-labeled imaging characteristics in the diagnosis of Alzheimer disease. MATERIALS AND METHODS: This study included 68 patients with clinically suspected Alzheimer disease who underwent both 3D arterial spin-labeling and SPECT imaging. Two readers independently assessed both images. Kendall W coefficients of concordance (K) were computed, and receiver operating characteristic analyses were performed for each reader. The differences between the images in regional perfusion distribution were evaluated by means of statistical parametric mapping, and the incidence of hypoperfusion of the cerebral watershed area, referred to as “borderzone sign” in the 3D arterial spin-labeled images, was determined. RESULTS: Readers showed K = 0.82/0.73 for SPECT/3D arterial spin-labeled imaging, and the respective areas under the receiver operating characteristic curve were 0.82/0.69 for reader 1 and 0.80/0.69 for reader 2. Statistical parametric mapping showed that the perisylvian and medial parieto-occipital perfusion in the arterial spin-labeled images was significantly higher than that in the SPECT images. Borderzone sign was observed on 3D arterial spin-labeling in 70% of patients misdiagnosed with Alzheimer disease. CONCLUSIONS: The diagnostic performance of 3D arterial spin-labeling and SPECT for Alzheimer disease was almost equivalent. Three-dimensional arterial spin-labeled imaging was more influenced by hemodynamic factors than was SPECT imaging.

Regional glucose metabolic reduction in dementia with Lewy bodies is independent of amyloid deposition

PurposeThere is evidence that some cases of patients with dementia with Lewy bodies (DLB) can demonstrate Alzheimer disease (AD) like reduced glucose metabolism without amyloid deposition. The aim of this study was to clarify whether regional hypometabolism is related to amyloid deposits in the DLB brain and measure the degree of regional hypometabolism.MethodsTen consecutive subjects with DLB and 10 AD patients who underwent both Pittsburgh compound B (PiB)-PET and 18F-fluoro-2-deoxyglucose (FDG)-PET were included in this study. Regional standardized uptake value ratio (SUVR)s normalised to cerebellar cortices were calculated in the FDG- and PiB-PET images.ResultsAll AD patients and five DLB patients showed amyloid deposits (PiB positive). In the DLB group the parietotemporal and occipital metabolism were significantly lower than those in the AD group but there was no difference between the posterior cingulate hypometabolism between DLB and AD groups. There were no differences in regional glucose metabolism between PiB positive and negative DLB patients.ConclusionsIn the DLB brain, it is suggested that decreased regional glucose metabolism is unrelated to amyloid deposits, although the hypometabolic area overlaps with the AD hypometabolic area and the degree of parietotemporal and occipital hypometabolism in DLB brain is much larger than that in AD brain.

Performance of 11C-Pittsburgh Compound B PET Binding Potential Images in the Detection of Amyloid Deposits on Equivocal Static Images

The goal of this study was to clarify whether binding potential (BP) images using 11C-Pittsburgh compound B (11C-PiB) and dynamic PET can reliably detect cortical amyloid deposits for patients whose 11C-PiB PET static images are ambiguous and whether visual ratings are affected by white matter retention. Methods: Static and BP images were constructed for 85 consecutive patients with cognitive impairment after 11C-PiB dynamic PET. Cortical uptake was visually assessed as positive, negative, or equivocal for both types of images. Quantitatively, the standardized uptake value ratio (SUVR) from the static image, the nondisplaceable BP from the dynamic image for mean gray matter uptake, and the ratio of gray matter uptake to white matter retention were compared among 11C-PiB–positive, 11C-PiB–equivocal, and 11C-PiB–negative groups. Results: Forty-three scans were visually assessed as 11C-PiB–positive in both the static and the BP images. Ten scans were 11C-PiB–equivocal in the static images. In 8 of them, the BP images were 11C-PiB–positive, whereas the other 2 were 11C-PiB–equivocal. Thirty-two scans were assessed as 11C-PiB–negative in the static images. In the BP images, 4 were 11C-PiB–positive and 2 were 11C-PiB–equivocal. The mean gray matter uptake of 11C-PiB in SUVR and nondisplaceable BP, respectively, showed statistically significant differences among the 11C-PiB–positive, 11C-PiB–equivocal, and 11C-PiB–negative groups. The ratio of gray matter uptake to white matter retention was lower in the BP images than static images from the 11C-PiB–negative and 11C-PiB–equivocal groups, whereas it was higher in the 11C-PiB–positive group. Conclusion: 11C-PiB PET BP images can clarify visual interpretation of clinical static 11C-PiB–equivocal images by reducing the interference of nonspecific white matter retention. We conclude that 11C-PiB–equivocal PET findings on static images reflect cortical amyloid deposits, which can be verified using BP images. Furthermore, quantitative assessments, such as SUVR and nondisplaceable BP, are of no use for correctly rating equivocal visual findings.

Regional Differences in Amyloid Deposition between 11C-Pib PET PositivePatients with and without Elevated Striatal Amyloid Uptake

Purpose: In subjects showing an increased level of 11C-Pittsburgh compound B (PiB) in positron emission tomography (PET) imaging of the brain, two groups can be distinguished: those with and without elevated PiB uptake in the striatum. We examined regional PiB uptake differences between these groups, and additionally compared them with PiB-negative subjects. Methods: This study included 141 subjects complaining of cognitive impairment. Their clinical diagnoses were Alzheimer’s disease (AD), mild cognitive impairment, dementia with Lewy bodies, frontotemporal lobar degeneration, or subjective cognitive impairment. PiB and 18F-fluorodeoxy-D-glucose (FDG) PET were performed in all subjects. PiB PET images were visually classified into three groups: 1) PiB-positive with uptake in any region of the cortex accompanied by striatal PiB uptake (STRPOS), 2) PiB-positive with cortical uptake but without striatal PiB uptake (STRNEG), and 3) both cortex and striatum PiB-negative (PiBNEG). Standardised uptake value ratios (SUVR) and regional differences in PiB uptake were evaluated using voxelbased analysis of PiB and FDG uptake images. Results: Eighty subjects were visually rated as PiB-positive: 11 had no increased PiB uptake in the striatal area, while 69 showed an elevated striatal PiB level. Sixty-one subjects were PiB-negative. Mean cortical SUVR was 1.46 ± 0.23 for STRNEG, 2.00 ± 0.44 for STRPOS and 0.99 ± 0.19 for PiBNEG. Apart from the striatum, PiB accumulation in the medial orbitofrontal cortex of STRPOS subjects was higher than in STRNEG subjects. No significant differences in regional FDG distribution were observed. Conclusion: PiB-positive cases with high striatal PiB uptake have an increased mean cortical SUVR in comparison to PiB-positive subjects without striatal uptake. This difference is most distinctive in the orbitofrontal cortex. We conclude that a high amyloid load in the striatum is linked to amyloid deposition occurring mostly in the frontal region, and may occur later in the course of AD progression.

18f-fdg Pet/ct Features of Chronic Sclerosing Sialadenitis Presenting as Localized Igg4-related Disease

Chronic sclerosing sialadenitis is a benign inflammatory condition that most commonly affects the submandibular gland in elderly individuals. It is currently known to belong to the spectrum of IgG4-related systemic diseases, which is reflected by systemic involvement on F-FDG PET/CT images. We presented a case of a 73-year-old man with histologically proven IgG4-related chronic sclerosing sialadenitis, unilateral localized form, on whole-body F-FDG PET/CT images that mimicked submandibular carcinoma with lymph node metastasis.