Purpose To investigate the hemodynamic changes of normal‐appearing white matter (NAWM) in hypertension using the 3D pseudocontinuous arterial spin labeling (pCASL) technique. Materials and Methods Seventy‐three subjects, including a patient group (n = 41; 30 males; age = 47.7 ± 8.3 years; test‐time blood pressure [BP] = 155 ± 23/98 ± 11 mmHg) and an age‐matched control group (n = 32; 14 males; age = 46 ± 8.3 years; test‐time BP = 117 ± 8/76 ± 10 mmHg), were recruited and scanned on a 3.0T magnetic resonance imaging (MRI) system using routine MRI sequences and 3D pCASL sequence. The routine MRI sequences were used to further define the NAWM. The cerebral blood flow (CBF) values in various regions of interest (ROIs) were extracted. One‐way analysis of variance (ANOVA) and unpaired t‐test were performed to evaluate the significance of the intergroup difference in CBF modifications. Results Compared to healthy volunteers, CBF values in global gray matter (GM) and various NAWM regions were found to be lower (P < 0.05) in hypertensive patients, except for genu of corpus callosum (CC), cingulate gyrus, amygdala, pallidum, putamen, and thalamus (P > 0.05). Furthermore, compared to the control group, mild hypertension showed significantly reduced CBF in various ROIs (P < 0.05), but no intergroup differences in GM, R anterior horn of periventricular WM, and genu of CC (P > 0.05), while moderate hypertension showed reduced CBF in all ROIs (P < 0.05). However, it was observed that, between mild and moderate hypertensive patients, there were no statistically significant difference in CBF values except for genu of CC (P < 0.05). Conclusion 3D pCASL has the ability to detect subtle hemodynamic abnormalities in NAWM regions at relatively early stages of hypertension. The observed decreases in CBF in these regions may suggest an increased risk of cerebral small vessel diseases. J. MAGN. RESON. IMAGING 2016;43:635–643.
Cerebral blood flow (CBF) in the human primary visual cortex is correlated with the loss of visual function in neuro-ophthalmological diseases. Advanced three-dimensional pseudo-continuous arterial spin labeling (3D pCASL), as a non-invasive method to access the CBF, can be a novel measurement to detect the visual cortex. The objective of the study was to assess the intra- and inter-scanner reliability of 3D pCASL of the visual cortex in healthy adults and suggest the selection of different post-labeling delay times (PLDs). For this reason, 3D pCASL was conducted in two 3.0T MR three times with twelve healthy volunteers at an interval of 10–15 days. The 1st and 3rd tests were performed on scanner-1, and the 2nd test was performed on scanner-2. The value of the CBF was abstracted from the visual cortex with two PLDs. The intra- and inter-scanner reliability and reproducibility were evaluated with the intraclass correlation coefficient (ICC) and Bland-Altman plots. By estimating the mean value of the CBF in the visual cortex, the intra-scanner results demonstrated the higher reliability (ICC for PLD = 1.5 second presented at 0.743 compared with 0.829 for PLD = 2.5 seconds), and the Bland-Altman plots showed the reproducibility at a longer PLD. We conclude that the calibrated 3D pCASL approach provides a highly reproducible measurement of the CBF of the visual cortex that can serve as a useful quantitative probe for research conducted at multiple centers and for the long-term observation of the clinical effects of neuro-opthalmological diseases.
Mutations in MARS gene cause dominant Charcot-Marie-Tooth disease (CMT) 2U. The aim of this study is to investigate phenotypic heterogeneities and peripheral neuropathology of MARS-related CMT patients. We identified a heterozygous p. R199Q mutation and an already reported heterozygous p. P800T mutation of MARS gene in two unrelated families using targeted next-generation sequencing. The first pedigree comprised three patients over three generations and the second pedigree comprised two patients over two generations. In addition of an asymptomatic carrier in the second pedigree, all patients presented with childhood-onset length dependent sensorimotor neuropathy with pes cavus. Nerve conduction studies revealed slowing of motor nerve conduction velocities (MNCV) of the median nerve indicating intermediate neuropathy in the patient with the p. R199Q mutation, and normal MNCV with reduced compound muscle action potential indicating axonal neuropathy in the patient with the p. P800T mutation. Magnetic resonance imaging detected a pattern of nerve changes similar to those in demyelinating polyneuropathies in intermediate type (p. R199Q mutation) patients compared with normal in the axonal type (p. P800T mutation) patients. Additionally, sural nerve biopsy revealed loss of myelinated axons with onion bulb formation in both mutations. By electron microscopy, a marked decrease of myelinated and unmyelinated fiber, neurofilaments aggregate with degenerating mitochondria and microtubule loss in axons were frequently found. Denervated Schwann cell complexes and few collagen pockets indicated involvement of unmyelinated Schwann cells. Therefore, the investigated MARS mutations cause not only the known axonal type but also intermediate type neuropathy with involvement of both axons and Schwann cells. Those findings are useful for the differential diagnosis of CMT patients with unknown MARS variants.
<abstract><p>The numerical solutions of time $ \alpha $-order $ (\alpha \in (0, 1)) $ Caputo fractional Fokker-Planck equations is considered. The constructed method is consist of the transformed $ L1 $ ($ TL1 $) scheme in the temporal direction and the Legendre-Galerkin spectral method in the spatial direction. It has been shown that the $ TL1 $ Legendre-Galerkin spectral method in $ L^2 $-norm is exponential order convergent in space and ($ 2-\alpha $)-th order convergent in time. Several numerical examples are given to verify the obtained theoretical results.</p></abstract>
Aims: Charcot–Marie–Tooth disease type 1A (CMT1A) is characterized by enlargement and stiffness of peripheral nerves due to edema with large numbers of “onion bulbs” in the endoneurium. Ultrasound elastography seems to be an ideal method to detect this condition. The aim of this study was to analyze the shear wave elastography (SWE) features of peripheral nerves in patients with CMT1A. Material and methods: We included 24 CMT1A patients with a mean age of 28 years, along with 24 age- and gender-matched controls. All patients presented with mutations of the PMP22 gene and showed length-dependent polyneuropathy. The motor nerve conduction velocity (MNCV) of the median nerve ranged from 5.2 to 37.4 m/s. SWE and cross-sectional area (CSA) were used to evaluate the bilateral median nerves at predefined sites in both patients and con-trols. Results: The average elastography value (EV) of the median nerve was 73.5±11.7 kPa in patients with CMT1A and 37.5±6.1 kPa in control subjects. The difference between the two groups was statistically significant (P<0.05). In CMT1A pa-tients, the average EV at the proximal and distal parts of the median nerve were 81.4±9.4 kPa and 65.2±8.1 kPa, respectively. The average CSAs at the proximal and distal parts of the median nerve were 0.29±0.06 cm2 and 0.20±0.05 cm2, respectively. The EV on SWE was positively correlated with CSA (p< 0.01) and negatively correlated with MNCV in the median nerve (p< 0.01). Conclusions: Peripheral nerve stiffness dramatically increases in CMT1A and is correlated with the severity of nerve involvement.
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