Maki Umino

A longitudinal study of neuromelanin-sensitive magnetic resonance imaging in Parkinson's disease.

PURPOSE Neuromelanin-sensitive MR imaging (NMI) is an increasingly powerful tool for the diagnosis of Parkinsons disease (PD). This study was undertaken to evaluate longitudinal changes on NMI in PD patients. METHODS We examined longitudinal changes on NMI in 14 PD patients. The area and contrast ratio (CR) of the substantia nigra pars compacta (SNc) were comparatively analyzed. RESULTS The total area and CR of the SNc upon follow-up NMI were significantly smaller than those on initial NMI (from 33.5±18.9 pixels and 6.35±2.86% to 21.5±16.7 pixels and 4.19±2.11%; Wilcoxon signed-rank test, p<0.001 and p=0.022, respectively). The area and CR of the dominant side SNc upon initial NMI were significantly greater than those on follow-up NMI (from 15.3±9.1 pixels and 6.5±2.7% to 7.9±8.5 pixels and 3.7±2.9%; Wilcoxon signed-rank test, p=0.002 and p=0.007, respectively). On a case-by-case basis, the area of the SNc invariably decreased upon follow-up NMI in all patients. We further demonstrated that the total area and CR of the SNc negatively correlated with disease duration (Pearson correlation coefficient, r=-0.63, p<0.001 and r=-0.41, p=0.031, respectively). In area analyses, our results demonstrated very high intraclass correlation coefficients for both intra- and inter-rater reliability. CONCLUSION NMI is a useful and reliable tool for detecting neuropathological changes over time in PD patients.

Low signal intensity in U-fiber identified by susceptibility-weighted imaging in two cases of progressive multifocal leukoencephalopathy

Magnetic resonance imaging (MRI) is a useful tool for diagnosing and monitoring progressive multifocal leukoencephalopathy (PML). Although characteristic MRI findings of PML are well known, we noted a potential new finding for this disease on susceptibility-weighted imaging (SWI). Two patients with PML were studied and followed using MRI. SWI revealed low signal intensities in U-fibers adjacent to the white matter lesions of PML. These findings progressed along with the disease progression. The cause underlying these findings remains unclear. This new finding suggests that SWI is useful for the diagnosis of PML. It can provide a helpful clue in a clinical setting.

Low-signal-intensity rim on susceptibility-weighted imaging is not a specific finding to progressive multifocal leukoencephalopathy

BACKGROUND Low-signal-intensity (LSI) rim along deep layers of the cerebral cortex is reportedly a susceptibility-weighted imaging (SWI) finding in progressive multifocal leukoencephalopathy (PML). We aimed to evaluate whether this finding can be identified in diseases other than PML. METHODS We retrospectively reviewed brain MR images from 5605 patients who underwent SWI at 3T; 370 patients with various diseases, who showed cortical and subcortical FLAIR high-signal lesions including U-fiber, were enrolled. The presence or absence of LSI rim on thin-slice SWI and hyperintense cortical signal (HCS) on T1-weighted images adjacent to LSI rim was analyzed. Signal changes of the LSI rim were assessed on serial SWI, if available. RESULTS Twenty-five of the 370 patients (6.8%) showed SWI LSI rim, in infarct (n=22) and encephalitis (n=3). HCS was apparent adjacent to SWI LSI rim in 17 patients (15 infarct, 2 encephalitis). Serial SWI was available for 17 patients, of whom 10 patients (8 infarct, 2 encephalitis) presented LSI rim later than 45days after onset. CONCLUSION LSI rim can be observed in infarct and encephalitis. Therefore, this finding is not specific to PML. LSI rim appears to be associated with HCS.

Cervical carotid plaque evaluation using 3D T1-weighted black-blood magnetic resonance imaging: Comparison of turbo field-echo and turbo spin-echo sequences.

PURPOSE To compare the capability of three-dimensional (3D) T1-weighted turbo field-echo (TFE) black-blood (BB) magnetic resonance imaging (MRI) and turbo-spin echo (TSE) BB MRI for discerning carotid plaques and the difference of signal intensities of the plaques from that of adjacent muscle in patients with cervical carotid stenosis. METHODS Cervical carotid stenosis was evaluated by 3.0-T MR in 43 patients (38 men and 5 women; age, 36-83 years; mean age, 70 years) during 8 months. The carotid BB MRI comprised 3D T1-weighted TSE BB (T1-TSEBB) and 3D T1-weighted TFE BB (T1-TFEBB) sequences. The delineation of the carotid plaque border was evaluated in comparison with digital subtraction angiography (DSA). The border between the plaque and vessel lumen was rated visually (4-point analysis) and quantitatively (contrast-to-noise ratio). The signal-intensity ratio (SIR) of the plaque to the adjacent muscle was also measured. Data of 3D T1-TSEBB and 3D T1-TFEBB were compared statistically using the Wilcoxon signed-rank test. RESULTS Visual and quantitative analyses revealed that the border between the plaque and vessel lumen was better delineated on 3D T1-TSEBB MRI than on 3D T1-TFEBB MRI (p<0.01, respectively). SIR of the plaque-to-adjacent muscle was higher on 3D T1- TFEBB MRI than on 3D T1-TSEBB MRI (p<0.05). High signal plaques with a SIR of >1.5 were underestimated on 3D T1-TSEBB MRI. CONCLUSIONS 3D T1-TSEBB MRI was superior to 3D T1-TFEBB MRI for delineating carotid plaques; however, high signal plaques were underestimated on 3D T1-TSEBB MRI.

3D double inversion recovery MR imaging: Clinical applications and usefulness in a wide spectrum of central nervous system diseases

Double inversion recovery (DIR) imaging provides two inversion pulses that attenuate signals from cerebrospinal fluid and normal white matter. This review was undertaken to describe the principle of the DIR sequence, the clinical applications of 3D DIR in various central nervous system diseases and the clinical benefits of the 3D DIR compared with those of other MR sequences. 3D DIR imaging provides better lesion conspicuity and topography than other MR techniques. It is particularly useful for diagnosing the following disease entities: cortical and subcortical abnormalities such as multiple sclerosis, cortical microinfarcts and cortical development anomalies; sulcal abnormalities such as meningitis and subacute/chronic subarachnoid hemorrhage; and optic neuritis caused by multiple sclerosis or neuromyelitis optica.

Ipilimumab-induced hypophysitis involving the optic tracts and tuber cinereum evaluated using 3D fluid-attenuated inversion recovery

Ipilimumab, a human monoclonal antibody against cytotoxic T-lymphocyte antigen 4, was approved by the U.S. FDA (Food and Drug Administration) in 2011 for the treatment of unresectable or metastatic malignant melanoma. Occurrence of hypophysitis, an immune-related adverse event due to ipilimumab use, has been frequently reported. We report a case of ipilimumab-induced hypophysitis involving the optic tracts and tuber cinereum, identified using 3D fluid-attenuated inversion recovery.

Background and distribution of lobar microbleeds in cognitive dysfunction

Cerebral microbleeds (CMBs) are often observed in memory clinic patients. It has been generally accepted that deep CMBs (D‐CMBs) result from hypertensive vasculopathy (HV), whereas strictly lobar CMBs (SL‐CMBs) result from cerebral amyloid angiopathy (CAA) which frequently coexists with Alzheimers disease (AD). Mixed CMBs (M‐CMBs) have been partially attributed to HV and also partially attributed to CAA. The aim of this study was to elucidate the differences between SL‐CMBs and M‐CMBs in terms of clinical features and regional distribution.

Suspected Metallic Embolism following Endovascular Treatment of Intracranial Aneurysms

SUMMARY: We describe a case series of suspected metallic embolism after coil embolization for intracranial aneurysms. Between January 2012 and December 2014, 110 intracranial aneurysms had been treated by coil embolization in our institution. In 6 cases, the postprocedural MR imaging revealed abnormal spotty lesions not detected on the preprocedural MR imaging. The lesions were also undetectable on the postprocedural CT scan. They were demonstrated as low-intensity spots on T1WI, T2WI, DWI, and T2*-weighted imaging. On DWI, they were accompanied by bright “halo,” and on T2*-weighted imaging, they showed a “blooming” effect. In 3 of the 6 cases, follow-up MR imaging was available and all the lesions remained and demonstrated no signal changes. Although histologic examination had not been performed, these neuroradiologic findings strongly supported the lesions being from metallic fragments. No specific responsible device was detected after reviewing all the devices used for the neuroendovascular treatment in the 6 cases.