Effect of Temporal Sampling Rate on Estimates of the Perfusion Parameters for Patients with Moyamoya Disease Assessed with Simultaneous Multislice Dynamic Susceptibility Contrast-enhanced MR Imaging.

PURPOSE: The effect of temporal sampling rate (TSR) on perfusion parameters has not been fully investigated in Moyamoya disease (MMD); therefore, this study evaluated the influence of different TSRs on perfusion parameters quantitatively and qualitatively by applying simultaneous multi-slice (SMS) dynamic susceptibility contrast-enhanced MR imaging (DSC-MRI). METHODS: DSC-MRI datasets were acquired from 28 patients with MMD with a TSR of 0.5 s. Cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), time to peak (TTP), and time to maximum tissue residue function (Tmax) were calculated for eight TSRs ranging from 0.5 to 4.0 s in 0.5-s increments that were subsampled from a TSR of 0.5 s datasets. Perfusion measurements and volume for chronic ischemic (Tmax ≥ 2 s) and non-ischemic (Tmax < 2 s) areas for each TSR were compared to measurements with a TSR of 0.5 s, as was visual perfusion map analysis. RESULTS: CBF, CBV, and Tmax values tended to be underestimated, whereas MTT and TTP values were less influenced, with a longer TSR. Although Tmax values were overestimated in the TSR of 1.0 s in non-ischemic areas, differences in perfusion measurements between the TSRs of 0.5 and 1.0 s were generally minimal. The volumes of the chronic ischemic areas with a TSR ≥ 3.0 s were significantly underestimated. In CBF and CBV maps, no significant deterioration was noted in image quality up to 3.0 and 2.5 s, respectively. The image quality of MTT, TTP, and Tmax maps for the TSR of 1.0 s was similar to that for the TSR of 0.5 s but was significantly deteriorated for the TSRs of ≥ 1.5 s. CONCLUSION: In the assessment of MMD by SMS DSC-MRI, application of TSRs of ≥ 1.5 s may lead to deterioration of the perfusion measurements; however, that was less influenced in TSRs of ≤ 1.0 s.

Insulin overdose complicated by treatment-induced acute hepatic steatosis in a nondiabetic patient.

Background: There are few reports of dextrose-associated hepatic steatosis during insulin overdose treatment. Reports in nondiabetic patients are extremely rare. There is inadequate knowledge about the clinical course and treatment. Case Presentation: A 37-year-old previously healthy, nondiabetic man self-administered 5,925 IU of insulin. On admission, his liver function tests were normal. However, following continued dextrose treatment, they increased, and he was diagnosed with hepatic steatosis. The liver function tests improved with decreasing dextrose dosage, and he was asymptomatic on discharge. Conclusion: Acute hepatic steatosis may occur in nondiabetic and diabetic patients during treatment requiring large doses of dextrose infusion, such as for an insulin overdose. In addition, the degree of liver damage might also be related to the dextrose dose. Therefore, careful glycemic control and minimization of the dextrose dosage are recommended for diabetic and nondiabetic patients.

Associations among q-space MRI, diffusion-weighted MRI and histopathological parameters in meningiomas.

OBJECTIVES: The purposes of this MR-based study were to calculate q-space imaging (QSI)-derived mean displacement (MDP) in meningiomas, to evaluate the correlation of MDP values with apparent diffusion coefficient (ADC) and to investigate the relationships among these diffusion parameters, tumour cell count (TCC) and MIB-1 labelling index (LI). METHODS: MRI, including QSI and conventional diffusion-weighted imaging (DWI), was performed in 44 meningioma patients (52 lesions). ADC and MDP maps were acquired from post-processing of the data. Quantitative analyses of these maps were performed by applying regions of interest. Pearson correlation coefficients were calculated for ADC and MDP in all lesions and for ADC and TCC, MDP and TCC, ADC and MIB-1 LI, and MDP and MIB-1 LI in 17 patients who underwent subsequent surgery. RESULTS: ADC and MDP values were found to have a strong correlation: r = 0.78 (P = <0.0001). Both ADC and MDP values had a significant negative association with TCC: r = -0.53 (p = 0.02) and -0.48 (P = 0.04), respectively. MIB-1 LI was not, however, found to have a significant association with these diffusion parameters. CONCLUSION: In meningiomas, both ADC and MDP may be representative of cell density. KEY POINTS: • Diffusion-weighted MRI offers possibilities to assess the aggressiveness of meningiomas. • The q-space imaging-derived mean displacement correlates strongly with apparent diffusion coefficients. • Both diffusion parameters showed a strong negative association with tumour cell counts. • Derived mean displacement may help assess the aggressiveness of meningiomas preoperatively.

Damage to the left ventral, arcuate fasciculus and superior longitudinal fasciculus-related pathways induces deficits in object naming, phonological language function and writing, respectively.

The anatomic localization of brain functions can be characterized via diffusion tensor imaging in patients with brain tumors and neurological symptoms. The goal of the present study was to evaluate the function of the ventral, arcuate fasciculus (AF) and the superior longitudinal fasciculus (SLF)-related language pathways using these techniques by analyzing 9 patients treated in our hospital between 2007 and 2011. In cases 1-3, the left ventral pathways, namely, the inferior longitudinal fasciculus, uncinate fasciculus or inferior fronto-occipital fasciculus, were mainly damaged, and the common dysfunction experienced by these patients was a deficit in object naming. In cases 4-6, the left SLF was mainly damaged, and the common deficit was dysgraphia. In cases 7-9, the left AF was mainly damaged, and almost all language functions related to phonology were abnormal. These results suggest that the left ventral, AF and SLF-related pathways are closely related to visual, auditory and hand-related language function, respectively.

Age-related white matter changes in high b-value q-space diffusion-weighted imaging.

INTRODUCTION: To assess and compare age-related diffusion changes in the white matter in different cerebral lobes, as quantified by diffusion-weighted imaging (DWI) and high b-value q-space imaging (QSI). METHODS: Seventy-three cases without neurological symptoms or imaging abnormalities were grouped by age as young (<30 years, n = 20), middle-aged (30-49 years, n = 19), old (50-69 years, n = 18), and very old (> 70 years, n = 16) and imaged by a 1.5-T MR scanner for DWI and QSI. Apparent diffusion coefficient (ADC) and mean displacement (MDP) values were calculated in the white matter of frontal, parietal, and temporal lobes and compared using Dunnett's test, with the young group as a control. RESULTS: MDP values in frontal and parietal lobes were significantly higher in old and very old age groups than in the young, while those in the temporal lobes were significantly higher only in the very old group. ADC values were significantly higher in all three lobes in the very old group. CONCLUSION: QSI is more sensitive than DWI to age-related myelin loss in white matter.

The left superior longitudinal fasciculus within the primary sensory area of inferior parietal lobe plays a role in dysgraphia of kana omission within sentences.

Functional neurological changes after surgery combined with diffusion tensor imaging (DTI) tractography can directly provide evidence of anatomical localization of brain function. Using these techniques, a patient with dysgraphia before surgery was analyzed at our hospital in 2011. The patient showed omission of kana within sentences before surgery, which improved after surgery. The brain tumor was relatively small and was located within the primary sensory area (S1) of the inferior parietal lobe (IPL). DTI tractography before surgery revealed compression of the branch of the superior longitudinal fasciculus (SLF) by the brain tumor. These results suggest that the left SLF within the S1 of IPL plays a role in the development of dysgraphia of kana omission within sentences.

High b-value q-space analyzed diffusion-weighted MRI using 1.5 tesla clinical scanner; determination of displacement parameters in the brains of normal versus multiple sclerosis and low-grade glioma subjects.

PURPOSE: We aimed to determine the displacement parameters in the brains of normal individuals relative to brain parenchymal abnormalities, such as multiple sclerosis (MS) and low-grade glioma, by q-space imaging (QSI) using 1.5-T magnetic resonance (MR) scanner. MATERIALS AND METHODS: Thirty-five normal, three pathologically proven low-grade glioma, and five MS subjects were imaged by a 1.5-T MR unit for QSI (b-values, 0-12,000 s/mm(2)). Mean displacement (MD) values in white matter (WM), gray matter (GM), and lateral ventricle (cerebrospinal fluid [CSF]) of normal subjects, plaques, and normal appearing WM (NAWM) of MS subjects and glioma lesions were calculated. Mann-Whitney U test was used for comparison. RESULTS: In normal subjects, MD values were 6.6 ± 0.2, 8.44 ± 0.41, and 17.08 ± 0.80 µm for WM, GM, and CSF, respectively, while those for NAWM and WM plaques in MS, and glioma lesions were significantly higher at 7.0 ± 0.17, 9.3 ± 2.3, and 9.6 ± 0.40 µm, respectively, compared to WM in normal subjects. CONCLUSION: We propose that the relative values of MD obtained by QSI in control and diseased tissues can be useful for diagnosing various WM abnormalities.

Right temporal lobe plays a role in verbal memory.

OBJECTIVES: Comparison of preoperative and postoperative neurological functions in patients undergoing resection of brain tumors, in combination with data from diffusion tensor imaging (DTI) studies, can provide direct evidence of anatomical localization of brain function. The goal of the present study was to use these techniques to characterize memory function of the right temporal lobe in five patients with right temporal lobe brain tumors. METHODS: Memory function was tested using the Wechsler Memory Scale-Revised (WMS-R) before and after surgery in five patients with right temporal lobe brain tumors. Preoperative DTI was performed in four of five cases. RESULTS: In all cases, general and verbal memory, including verbal paired association, significantly improved after surgery (P<0.05). The right inferior longitudinal fasciculus (ILF) was compressed by the tumor in all cases. CONCLUSION: These results suggest that the right temporal lobe plays a role in verbal memory and that this function may be associated with the right ILF.

A comparison of mean displacement values using high b-value Q-space diffusion-weighted MRI with conventional apparent diffusion coefficients in patients with stroke.

RATIONALE AND OBJECTIVES: Q-space analysis using high b-value diffusion-weighted magnetic resonance (MR) data provides information on tissue microstructure in contrast to conventional MR imaging (MRI) based on low b-value diffusion-weighted imaging (DWI). The purpose of this study was to evaluate the use of mean displacement (MDP) map in stroke patients using q-space diffusion-weighted MRI (QSI). MATERIALS AND METHODS: Twenty-one patients presenting with a total of 22 acute or subacute cerebral infarctions were included. MR protocol consisted of conventional MR sequences, DWI (b-value; 1000 s/mm(2)) and QSI (b-value; maximum 12,000 s/mm(2)). Apparent diffusion coefficient (ADC) maps of conventional DWI and MDP maps of QSI data were obtained and compared in the ischemic lesions and corresponding normal tissues. RESULTS: Decreased ADC values were present in all lesions. There was no correlation between ADC and MDP values in the lesions (r = 0.21). MDP values of the lesions were 8.60 ± 1.26 µm (mean ± SD). Most of the lesions (16/22) had higher MDP values than normal brain tissue. Three lesions showed lower MDP values and three showed mixed MDP values. CONCLUSIONS: The MDP maps using QSI data provides additional information for stroke patients compared to conventional DWI.

Damage to the upper portion of area 19 and the deep white matter in the left inferior parietal lobe, including the superior longitudinal fasciculus, results in alexia with agraphia.

Analysis of lesions and symptoms in patients with brain tumors combined with information from diffusion tensor imaging provides direct evidence of the anatomical localization of brain function. Using these methods, we evaluated 8 patients who underwent surgery for metastatic brain tumors located in the left occipital lobes between 2007 and 2009. Preoperatively, 4 patients (cases 1-4) had alexia with agraphia while the other 4 patients (cases 5-8) did not. Tractography for the superior longitudinal fasciculus (SLF) was performed before surgery in case 1. The common brain tumors in cases 1-4 were located in the upper portion of area 19, and peritumor edema in that area resulted in compromise of the deep white matter of the inferior parietal lobe (IPL). The SLF was compressed and disrupted in the white matter of the IPL near the upper portion of area 19 in case 1. In cases 5-8, the brain tumors were not located in the upper portion of area 19. These results suggest that damage to the upper portion of area 19 and to the white matter in the left IPL, including the SLF, resulted in alexia with agraphia.

Damage of left temporal lobe resulting in conversion of speech to Sutra, a Buddhist prayer stored in the right hemisphere.

The present study describes a case of a right-handed 74-year-old woman with a brain tumor who showed conversion of speech to Sutra, a Buddhist prayer, which was stored in the right hemisphere according to the Wada test. After surgery, relative improvement in the speech disorder was observed, and frequency of speech production of simple normal words with normal phonology increased. These observations indicate that damage to left temporal lobe resulted in conversion of speech to Sutra, and that Sutra was stored in this patient's right hemisphere.

Molecular characterization of the major capsid protein VP6 of bovine group B rotavirus and its use in seroepidemiology.

The major inner capsid protein (VP6) gene of the bovine group B rotavirus (GBR) Nemuro strain is 1269 nt in length and contains one open reading frame encoding 391 aa. Nucleotide and amino acid sequence identities of the Nemuro VP6 gene compared with the published corresponding human and rodent GBR genes were respectively 66-67 and 70-72 %, which are notably lower than those between human and rodent viruses (72-73 and 83-84 %, respectively). Overall identities of VP6 genes among GBRs were substantially lower than those among both group A rotaviruses (GARs) and group C rotaviruses (GCRs) derived from different species of mammals. These results demonstrate that bovine GBR is remarkably distinct from other GBRs and that GBRs from different species may have had a longer period of divergence than GARs and GCRs. Recombinant VP6 was generated with a baculovirus expression system and used for an ELISA to detect GBR antibodies. All 13 paired sera from adult cows with GBR-induced diarrhoea in the field showed antibody responses in the ELISA. In serological surveys of GBR infection using the ELISA, 47 % of cattle sera were positive for GBR antibodies, with a higher antibody prevalence in adults than in young cattle. In pigs, a high prevalence of GBR antibodies (97 %) was detected in sera from sows. These results suggest that GBR infection is common in cattle and pigs, notwithstanding the scarcity of reports of GBR detection in these species to date.