Characteristic asymmetric limbic and anterior temporal atrophy in demented patients with pathologically confirmed argyrophilic grain disease.

PURPOSE: The purpose of this study is to clarify the characteristic structural magnetic resonance imaging (MRI) findings in demented patients with pathologically confirmed argyrophilic grain disease (AGD). METHODS: Nine pathologically confirmed AGD patients with cerebral three-dimensional T1-weighted MRI were evaluated in this study. In addition to visual rating scales of atrophic and asymmetric changes in the limbic and temporal lobes, voxel-based morphometry (VBM) was performed to assess group difference between pathologically confirmed AGD and Alzheimer's disease (AD) patients. RESULTS: On visual analyses of AGD patients, the medial temporal, anterior temporal, and posterior temporal atrophy scores were 3.3 ± 0.7, 1.7 ± 0.5, and 1.0 ± 0.7, respectively. Asymmetric scores of the hippocampus and parahippocampal gyrus, amygdala and ambient gyrus, anterior temporal, and posterior temporal lobes were rated as 1.1 ± 0.7, 1.6 ± 0.5, 1.3 ± 0.8, and 0.4 ± 0.7, respectively. In spite of no statistical differences in atrophic scores, AGD patients showed the higher score and proportion of anterior temporal asymmetric score than AD (p = 0.03 and 0.02). Compared with controls, VBM analysis revealed left dominant asymmetric atrophy predominantly in the limbic and anterior temporal lobe in AGD patients. By contrast, there was no significant gray matter reduction between AGD and AD patients. CONCLUSIONS: Asymmetric atrophy relatively localized to the anterior temporal and limbic lobes including the amygdala and ambient gyrus is a characteristic MRI finding of AGD. For the precise antemortem diagnosis, especially to differentiation from AD, it is important to pay attention to this asymmetric change.

Computed-tomography-guided anatomic standardization for quantitative assessment of dopamine transporter SPECT.

PURPOSE: For the quantitative assessment of dopamine transporter (DAT) using [123I]FP-CIT single-photon emission computed tomography (SPECT) (DaTscan), anatomic standardization is preferable for achieving objective and user-independent quantification of striatal binding using a volume-of-interest (VOI) template. However, low accumulation of DAT in Parkinson's disease (PD) would lead to a deformation error when using a DaTscan-specific template without any structural information. To avoid this deformation error, we applied computed tomography (CT) data obtained using SPECT/CT equipment to anatomic standardization. METHODS: We retrospectively analyzed DaTscan images of 130 patients with parkinsonian syndromes (PS), including 80 PD and 50 non-PD patients. First we segmented gray matter from CT images using statistical parametric mapping 12 (SPM12). These gray-matter images were then anatomically standardized using the diffeomorphic anatomical registration using exponentiated Lie algebra (DARTEL) algorithm. Next, DaTscan images were warped with the same parameters used in the CT anatomic standardization. The target striatal VOIs for decreased DAT in PD were generated from the SPM12 group comparison of 20 DaTscan images from each group. We applied these VOIs to DaTscan images of the remaining patients in both groups and calculated the specific binding ratios (SBRs) using nonspecific counts in a reference area. In terms of the differential diagnosis of PD and non-PD groups using SBR, we compared the present method with two other methods, DaTQUANT and DaTView, which have already been released as software programs for the quantitative assessment of DaTscan images. RESULTS: The SPM12 group comparison showed a significant DAT decrease in PD patients in the bilateral whole striatum. Of the three methods assessed, the present CT-guided method showed the greatest power for discriminating PD and non-PD groups, as it completely separated the two groups. CONCLUSION: CT-guided anatomic standardization using the DARTEL algorithm is promising for the quantitative assessment of DaTscan images.

Intraventricular temperature measured by diffusion-weighted imaging compared with brain parenchymal temperature measured by MRS in vivo.

We examined and compared the temperatures of the intraventricular cerebrospinal fluid (Tv ) and the brain parenchyma (Tp ) using MRI, with reference to the tympanic membrane temperature (Tt ) in healthy subjects. We estimated Tv and Tp values from data gathered simultaneously by MR diffusion-weighted imaging (DWI) and MRS, respectively, in 35 healthy volunteers (17 males, 18 females; age 25-78 years). We also obtained Tt values just before each MR examination to evaluate the relationships among the three temperatures. There were significant positive correlations between Tv and Tp (R = 0.611, p < 0.001). The correlation was also significant after correction for Tt (R = 0.642, p < 0.001). There was no significant correlation between Tv and Tt or between Tp and Tt in the men or the women. Negative correlations were found between Tv and age and between Tp and age in the males but not females. DWI thermometry seems to reflect the intracranial environment as accurately as MRS thermometry. An age-dependent decline in temperature was evident in our male subjects by both DWI and MRS thermometry, probably due to the decrease in cerebral metabolism with age. Copyright © 2016 John Wiley & Sons, Ltd.

Impaired cerebral blood flow networks in temporal lobe epilepsy with hippocampal sclerosis: A graph theoretical approach.

Graph theory is an emerging method to investigate brain networks. Altered cerebral blood flow (CBF) has frequently been reported in temporal lobe epilepsy (TLE), but graph theoretical findings of CBF are poorly understood. Here, we explored graph theoretical networks of CBF in TLE using arterial spin labeling imaging. We recruited patients with TLE and unilateral hippocampal sclerosis (HS) (19 patients with left TLE, and 21 with right TLE) and 20 gender- and age-matched healthy control subjects. We obtained all participants' CBF maps using pseudo-continuous arterial spin labeling and analyzed them using the Graph Analysis Toolbox (GAT) software program. As a result, compared to the controls, the patients with left TLE showed a significantly low clustering coefficient (p=0.024), local efficiency (p=0.001), global efficiency (p=0.010), and high transitivity (p=0.015), whereas the patients with right TLE showed significantly high assortativity (p=0.046) and transitivity (p=0.011). The group with right TLE also had high characteristic path length values (p=0.085), low global efficiency (p=0.078), and low resilience to targeted attack (p=0.101) at a trend level. Lower normalized clustering coefficient (p=0.081) in the left TLE and higher normalized characteristic path length (p=0.089) in the right TLE were found also at a trend level. Both the patients with left and right TLE showed significantly decreased clustering in similar areas, i.e., the cingulate gyri, precuneus, and occipital lobe. Our findings revealed differing left-right network metrics in which an inefficient CBF network in left TLE and vulnerability to irritation in right TLE are suggested. The left-right common finding of regional decreased clustering might reflect impaired default-mode networks in TLE.

[Imaging-Based Diagnosis of Craniocervical Artery Dissections: A Strategy Focusing on the Pathological Condition and MRI Technique].

Magnetic resonance imaging (MRI) is a non-invasive and useful imaging modality with a high contrast resolution to diagnose craniocervical artery dissections. However, to avoid misinterpretations and misdiagnosis, it is mandatory to understand not only the pathological condition of craniocervical artery dissection, but also the principles of MRI techniques. In this manuscript, the details of MRI findings, especially when using high-resolution vessel wall imaging, are discussed.

Extensive perivascular dissemination of cerebral miliary tuberculomas: a case report and review of the literature.

Cerebral tuberculosis (TB) presents most frequently as meningitis in the basilar cistern; however, it can also manifest in various other ways, such as localized encephalitis, abscess, and tuberculoma. Here, focusing on imaging findings, we report an immunocompetent case who demonstrated multiple parenchymal lesions and was diagnosed with cerebral TB after testing positive on QuantiFERON (QTF); her clinical signs/symptoms and laboratory findings responded well to anti-TB medication therapy. The patient was a 60-year-old woman with the chief complaints of headache and consciousness disturbance. On admission, cerebrospinal fluid (CSF) examination showed increased monocyte predominance. T2-weighted images showed multiple, widely distributed hyperintense lesions in the periventricular and deep white matter. Gadolinium-enhanced three-dimensional gradient echo T1-weighed images revealed numerous granules or faint, small, enhanced foci in lesions in the periventricular and deep white matter, central gray matter, and hippocampus. Some abnormal sulcal enhancement was detected in the pia mater, indicating meningitis. Clinically, the diagnosis was difficult to make, but as the QTF result was positive, anti-TB drugs were administered, after which both the symptoms and CSF cell count showed improvement.

Effects of pure and hybrid iterative reconstruction algorithms on high-resolution computed tomography in the evaluation of interstitial lung disease.

OBJECTIVES: To compare image quality characteristics of high-resolution computed tomography (HRCT) in the evaluation of interstitial lung disease using three different reconstruction methods: model-based iterative reconstruction (MBIR), adaptive statistical iterative reconstruction (ASIR), and filtered back projection (FBP). METHODS: Eighty-nine consecutive patients with interstitial lung disease underwent standard-of-care chest CT with 64-row multi-detector CT. HRCT images were reconstructed in 0.625-mm contiguous axial slices using FBP, ASIR, and MBIR. Two radiologists independently assessed the images in a blinded manner for subjective image noise, streak artifacts, and visualization of normal and pathologic structures. Objective image noise was measured in the lung parenchyma. Spatial resolution was assessed by measuring the modulation transfer function (MTF). RESULTS: MBIR offered significantly lower objective image noise (22.24±4.53, P<0.01 among all pairs, Student's t-test) compared with ASIR (39.76±7.41) and FBP (51.91±9.71). MTF (spatial resolution) was increased using MBIR compared with ASIR and FBP. MBIR showed improvements in visualization of normal and pathologic structures over ASIR and FBP, while ASIR was rated quite similarly to FBP. MBIR significantly improved subjective image noise (P<0.01 among all pairs, the sign test), and streak artifacts (P<0.01 each for MBIR vs. the other 2 image data sets). CONCLUSION: MBIR provides high-quality HRCT images for interstitial lung disease by reducing image noise and streak artifacts and improving spatial resolution compared with ASIR and FBP.

Noninvasive detection of focal brain hyperthermia related to continuous epileptic activities using proton MR spectroscopy.

Recent studies using rat models suggested that epileptic discharges (EDs) can induce focal brain hyperthermia, but such ED-related hyperthermia has not been confirmed in humans. We examined hyperthermia of the focus of epilepsy using noninvasive proton magnetic resonance spectroscopy (1H-MRS) thermometry. We recruited six pediatric patients with refractory daily seizures, continuous interictal epileptic discharges, and concordant focus lesions on MRI who had undergone comprehensive presurgical exams. 1H-MRS thermometry calculated the temperatures of the presumed epileptogenic lesions, and we examined the contralateral counterparts in each patient as controls. As a result, the mean temperature of the epileptogenic foci (36.81°C) was significantly higher than that of the controls (36.01°C). The mean difference was 0.81°C (95%CI: 0.22-1.39, p=0.017). 1H-MRS thermometry may have the ability to noninvasively detect focal brain hyperthermia related to continuous EDs in human subjects, and to contribute to a better understanding and focus detection of epilepsy.

Solitary synovial chondromatosis arising in the gluteus maximus bursa: computed tomography and magnetic resonance imaging findings.

Chondral tumors in soft tissue are referred to as soft-tissue chondromas or extraskeletal chondromas, or as synovial chondromatosis if they arise in synovial tissue. We report the case of a 29-year-old man with synovial chondromatosis, also called synovial osteochondromatosis, which appeared in a solitary and extra-articular form. On magnetic resonance imaging (MRI) and computed tomography, the central portion of the tumor showed similar characteristics to bone marrow, despite the absence of any connection to adjacent bone. T2-weighted imaging displayed marked peripheral hyperintensity consistent with a cartilaginous area. These findings suggested the presence of enchondral ossification and were similar to those of skeletal osteochondroma, with the exception of the absence of attachment to bone. MRI is useful for distinguishing solitary synovial chondromatosis from other lesions, such as myositis ossificans, extraskeletal chondrosarcoma, and parosteal osteosarcoma.

Noninvasive evaluation of the correlation between regional cerebral blood flow and intraventricular brain temperature in temporal lobe epilepsy.

INTRODUCTION: In temporal lobe epilepsy (TLE), an uncoupling of cerebral blood flow (CBF) and metabolism is indicated. The aim of this study was to clarify this relationship by investigating intraventricular brain temperature (BT) and CBF in TLE using a noninvasive MRI technique. MATERIAL AND METHODS: We recruited 38 subjects with left TLE and 39 subjects with right TLE. All patients underwent an MRI examination including diffusion-weighted imaging (DWI) and pseudo-continuous arterial spin labeling (pCASL). Intraventricular BT was calculated by a DWI thermometric technique, and regional CBF was obtained from pCASL images, and we analyzed the relationship between them using the statistical parametric mapping 8 software (SPM8). RESULTS: In only the left TLE group, there was a significant negative correlation between CBF and BT in the left inferior frontal gyrus. Positive correlations in the bilateral posterior poles were also found at the trend level in left TLE group. The patients with right TLE showed no significant correlation. CONCLUSION: Our results may reflect a regional uncoupling of blood flow and metabolism in those brain areas, and they may indicate that TLE has different metabolic regulation systems in the brain.

Striatal glucose hypometabolism in preadolescent-onset dentatorubral-pallidoluysian atrophy.

Dentatorubral-pallidoluysian atrophy (DRPLA) is hereditary spinocerebellar degeneration presenting various symptoms in association with expansion of the CAG repeat in Atrophin-1 gene. The functional neuroimaging of DRPLA has been poorly investigated. The purpose of this study was to examine (18)F-fluorodeoxyglucose-positron emission tomography ((18)F-FDG-PET) findings of DRPLA. We retrospectively investigated the cases of 14 consecutive genetically confirmed DRPLA patients at our institute. Four juvenile-onset patients underwent (18)F-FDG-PET because of intractable seizures. Their (18)F-FDG-PET images, clinical profiles and MRI findings were evaluated. For quantitative comparison, 3 healthy volunteers also underwent (18)F-FDG-PET as controls. All four patients presented progressive myoclonus epilepsy without MRI abnormalities. Both the visual and quantitative assessments of their (18)F-FDG-PET findings demonstrated bistriatal hypometabolism in only the two preadolescent-onset patients with larger CAG repeat size, whereas the two other later-onset patients showed no hypometabolism in the striatum. Bistriatal glucose hypometabolism in preadolescent-onset DRPLA patients might reflect more severe degeneration. This finding could contribute to a better understanding of DRPLA.

White matter abnormalities in patients with temporal lobe epilepsy and amygdala enlargement: Comparison with hippocampal sclerosis and healthy subjects.

PURPOSE: Cases of temporal lobe epilepsy (TLE) with ipsilateral amygdala enlargement (AE) have increasingly been reported. However, the white matter (WM) abnormalities of TLE patients with AE remain poorly investigated. Here we explored macrostructural and microstructural WM abnormalities in TLE patients with AE compared to normal controls and TLE patients with hippocampal sclerosis (HS). MATERIAL AND METHODS: We selected 17 patients with unilateral TLE with AE (TLE-AE) based on automated amygdala volumetry using FreeSurfer software, and 34 healthy controls and 35 patients with unilateral TLE with HS (TLE-HS) were also recruited. Subsequently, differences in gray matter (GM) and WM volumes and fractional anisotropy (FA) among the three groups were analyzed using SPM8 software. RESULTS: The volume analysis of GM obtained results that are consistent with the structural characteristics of TLE with AE and with HS (i.e. amygdala increase in the TLE-AE, and mesial temporal atrophy in the TLE-HS). In the volume of WM, only the TLE-HS patients had WM reductions mainly in the ipsilateral temporal lobe. Compared to the controls, the TLE-AE group showed a significant FA decrease in the ipsilateral anterior cingulum and the corpus callosum, whereas an extended FA decrease in the whole cerebrum was observed in the TLE-HS group. CONCLUSION: Our findings regarding the WM of TLE patients with AE may reflect characteristic pathophysiology such as the anatomical and functional connection between the amygdala and medial prefrontal cortex, and our results may thus provide insights into TLE with AE.

The cingulate island sign within early Alzheimer's disease-specific hypoperfusion volumes of interest is useful for differentiating Alzheimer's disease from dementia with Lewy bodies.

BACKGROUND: In addition to occipital hypoperfusion, preserved metabolism of the posterior cingulate gyri (PCG) relative to the precunei is known as the cingulate island sign (CIS) in the patients with dementia with Lewy bodies (DLB). CIS has been detected using [(18)F]fluorodeoxyglucose positron emission tomography but not using brain perfusion single-photon emission computed tomography (SPECT). The purpose of this study was to optimize brain perfusion SPECT to enable differentiation of DLB from Alzheimer's disease (AD) using CIS and occipital hypoperfusion. Eighteen patients with probable DLB and 17 age-matched Pittsburgh compound B-positive patients with AD underwent technetium-99m ethyl cysteinate dimer SPECT. SPECT Z-score maps were generated using the easy Z-score imaging system (eZIS) analysis software (Matsuda H, Mizumura S, Nagao T, Ota T, Iizuka T, Nemoto K, Takemura N, Arai H, Homma A, AJNR Am J Neuroradiol 28(4):731-6, 2007), which included volumes of interest (VOIs) in which a group comparison between patients with AD and cognitively normal subjects revealed significant relative hypoperfusion. We used the Montreal Neurological Institute (MNI) space anatomical border to divide the bilateral PCG to precunei VOIs into two parts, the PCG and precunei. Z-scores in the PCG, precunei, and occipital areas and ratios were analysed and compared with receiver operating characteristic (ROC) curve analyses. RESULTS: The largest area under the curve (AUC) value for use in differentiating DLB from AD with the ratio of PCG to medial occipital was 0.87; the accuracy, sensitivity, and specificity were 85.7, 88.9, and 82.4 %, respectively. The AUC with the ratio of PCG to the precuneus was smaller, and it was 0.85, though no significant difference was observed between these two AUCs. CONCLUSIONS: The Z-score ratio of the PCG within the early-AD-specific VOI to medial-occipital area is clinically useful in discriminating demented patients with DLB from those with AD.

Automated subfield volumetric analysis of hippocampus in temporal lobe epilepsy using high-resolution T2-weighed MR imaging.

BACKGROUND AND PURPOSE: Automated subfield volumetry of hippocampus is desirable for use in temporal lobe epilepsy (TLE), but its utility has not been established. Automatic segmentation of hippocampal subfields (ASHS) and the new version of FreeSurfer software (ver.6.0) using high-resolution T2-weighted MR imaging are candidates for this volumetry. The aim of this study was to evaluate hippocampal subfields in TLE patients using ASHS as well as the old and new versions of FreeSurfer. MATERIALS AND METHODS: We recruited 50 consecutive unilateral TLE patients including 25 with hippocampal sclerosis (TLE-HS) and 25 without obvious etiology (TLE-nonHS). All patients and 45 healthy controls underwent high-resolution T2-weighted and 3D-volume T1-weighted MRI scanning. We analyzed all of their MR images by FreeSurfer ver.5.3, ver.6.0 and ASHS. For each subfield, normalized z-scores were calculated and compared among groups. RESULTS: In TLE-HS groups, ASHS and FreeSurfer ver.6.0 revealed maximal z-scores in ipsilateral cornu ammonis (CA) 1, CA4 and dentate gyrus (DG), whereas in FreeSurfer ver.5.3 ipsilateral subiculum showed maximal z-scores. In TLE-nonHS group, there was no significant volume reduction by either ASHS or FreeSurfer. CONCLUSIONS: ASHS and the new version of FreeSurfer may have an advantage in compatibility with existing histopathological knowledge in TLE patients with HS compared to the old version of FreeSurfer (ver.5.3), although further investigations with pathological findings and/or surgical outcomes are desirable.

Graph Theoretical Analysis of Structural Neuroimaging in Temporal Lobe Epilepsy with and without Psychosis.

PURPOSE: Psychosis is one of the most important psychiatric comorbidities in temporal lobe epilepsy (TLE), and its pathophysiology still remains unsolved. We aimed to explore the connectivity differences of structural neuroimaging between TLE with and without psychosis using a graph theoretical analysis, which is an emerging mathematical method to investigate network connections in the brain as a small-world system. MATERIALS AND METHODS: We recruited 11 TLE patients with unilateral hippocampal sclerosis (HS) presenting psychosis or having a history of psychosis (TLE-P group). As controls, 15 TLE patients with unilateral HS without any history of psychotic episodes were also recruited (TLE-N group). For graph theoretical analysis, the normalized gray matter images of both groups were subjected to Graph Analysis Toolbox (GAT). As secondary analyses, each group was compared to 14 age- and gender-matched healthy subjects. RESULTS: The hub node locations were found predominantly in the ipsilateral hemisphere in the TLE-N group, and mainly on the contralateral side in the TLE-P group. The TLE-P group showed significantly higher characteristic path length, transitivity, lower global efficiency, and resilience to random or targeted attack than those of the TLE-N group. The regional comparison in betweenness centrality revealed significantly decreased connectivity in the contralateral temporal lobe, ipsilateral middle frontal gyrus, and bilateral postcentral gyri in the TLE-P group. The healthy subjects showed well-balanced nodes/edges distributions, similar metrics to TLE-N group except for higher small-worldness/modularity/assortativity, and various differences of regional betweenness/clustering. CONCLUSION: In TLE with psychosis, graph theoretical analysis of structural imaging revealed disrupted connectivity in the contralateral hemisphere. The network metrics suggested that the existence of psychosis can bring vulnerability and decreased efficiency of the whole-brain network. The sharp differences in structural networks between morphologically homogeneous groups are remarkable and may contribute to a better understanding of psychosis in TLE.

The magnetic resonance imaging spectrum of Pelizaeus-Merzbacher disease: A multicenter study of 19 patients.

PURPOSE: We retrospectively evaluated the imaging spectrum of Pelizaeus-Merzbacher disease (PMD) in correlation with the clinical course and genetic abnormality. METHODS: We collected the magnetic resonance imaging (MRI) findings of 19 genetically proven PMD patients (all males, aged 0-29years old) using our integrated web-based MRI data collection system from 14 hospitals. The patterns of hypomyelination were determined mainly by the signals of the cerebrum, corticospinal tract, and brainstem on T2-weighted images (T2WI). We assessed the degree of myelination age on T1-weighted images (T1WI) and T2WI independently, and we evaluated cerebellar and callosal atrophy. The clinical severity and genetic abnormalities (causal mutations of the proteolipid protein gene PLP1) were analyzed together with the imaging findings. RESULTS: The clinical stage tended to be more severe when the whole brainstem, or corticospinal tract in the internal capsule showed abnormally high intensity on T2WI. Diffuse T2-high signal of brainstem was observed only in the patients with PLP1 point mutation. Myelination age "before birth" on T1WI is a second manifestation correlated with the clinically severe phenotypes. On the other hand, eight patients whose myelination ages were > 4months on T1WI were associated with mild clinical phenotypes. Four of them showed almost complete myelination on T1WI with a discrepancy in myelination age between T1WI and T2WI. A random and patchy pattern of myelination on T2WI was noted in one patient with PLP1 point mutation. Advanced myelination was observed in three of the seven followed-up patients. Four patients had atrophy of the cerebellum, and 17 patients had atrophy of the corpus callosum. CONCLUSION: Our multicenter study has demonstrated a wide variety of imaging findings of PMD. Signal intensity of brainstem and corticospinal tract of internal capsule would be the points to presume clinical severity in PMD patients. The spectrum of MRI findings should be kept in mind to diagnose PMD and to differentiate from other demyelinating leukodystrophies.

Intraventricular cerebrospinal fluid temperature analysis using MR diffusion-weighted imaging thermometry in Parkinson's disease patients, multiple system atrophy patients, and healthy subjects.

PURPOSE: We examined the temperature of the intraventricular cerebrospinal fluid (Tv) in patients with Parkinson's disease (PD) and those with multiple system atrophy (MSA) in comparison with healthy subjects, and we examined normal changes in this temperature with aging. METHODS: Tv was estimated by magnetic resonance (MR) diffusion-weighted imaging (DWI) thermometry in 36 PD patients (19 males, 17 females), 34 MSA patients (17 males, 17 females), 64 age-matched controls (27 men, 37 women), and 114 all-age adult controls (47 men, 67 women; 28-89 years old). The volume of lateral ventricles was also estimated using FreeSurfer in all subjects. Tv and ventricular volume data were compared among the PD and MSA patients and age-matched controls. We also evaluated the relationship between Tv and age in the 114 all-age controls, controlling for ventricular volume. Men and women were analyzed separately. RESULTS: The male PD and MSA patients had significantly higher Tv values compared to the male controls, with no significant difference in ventricular volume among them. There was no significant difference in Tv between the female patients and controls. In the all-age male controls, there was a significant negative correlation between Tv and age controlling for ventricular volume, and this was not observed in the women. CONCLUSION: DWI thermometry is a useful and easy method for demonstrating an altered intracranial environment in male patients and healthy controls, but not in females. DWI thermometry can thus be used to help to explore the pathophysiology of Parkinsonian syndromes and to differentiate individuals affected by neurodegenerative disease with autonomic dysfunction from those without it.