PURPOSE: To investigate the utility of diffusion tensor imaging (DTI) in determining the microstructural integrity of sciatic and peroneal nerves and its correlation with the MRI grading of muscle atrophy severity and clinical function in CMT as determined by the CMT neuropathy score (CMTNS).
STUDY TYPE: Prospective case-control.
SUBJECTS: Nine CMT patients and nine age-matched controls.
FIELD STRENGTH/SEQUENCE: 3 T T1 -weighted in-/out-of phase spoiled gradient recalled echo (SPGR) and DTI sequences.
ASSESSMENT: Fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD), and mean diffusivity (MD) values for sciatic and peroneal nerves were obtained from DTI. Muscle atrophy was graded according to the Goutallier classification using in-/out-of phase SPGRs. DTI parameters and muscle atrophy grades were compared between CMT and controls, and the relationship between DTI parameters, muscle atrophy grades, and CMTNS were assessed.
STATISTICAL TESTS: The Wilcoxon Signed Ranks test was used to compare DTI parameters between CMT and controls. The relationship between DTI parameters, muscle atrophy grades, and CMTNS were analyzed using the Spearman correlation. Receiver operating characteristic (ROC) analyses of DTI parameters that can differentiate CMT from healthy controls were done.
RESULTS: There was a significant reduction in FA and increase in RD of both nerves (P
METHODS: Five APT quantification methods, including asymmetry analysis and its variants as well as two Lorentzian model-based methods, were applied to data acquired from six rats that underwent middle cerebral artery occlusion scanned at 9.4T. Diffusion and perfusion-weighted images, and water relaxation time maps were also acquired to study the relationship of these conventional imaging modalities with the different APT quantification methods.
RESULTS: The APT ischemic area estimates had varying sizes (Jaccard index: 0.544 ≤ J ≤ 0.971) and had varying correlations in their distributions (Pearson correlation coefficient: 0.104 ≤ r ≤ 0.995), revealing discrepancies in the quantified ischemic areas. The Lorentzian methods produced the highest contrast-to-noise ratios (CNRs; 1.427 ≤ CNR ≤ 2.002), but generated APT ischemic areas that were comparable in size to the cerebral blood flow (CBF) deficit areas; asymmetry analysis and its variants produced APT ischemic areas that were smaller than the CBF deficit areas but larger than the apparent diffusion coefficient deficit areas, though having lower CNRs (0.561 ≤ CNR ≤ 1.083).
CONCLUSION: There is a need to further investigate the accuracy and correlation of each quantification method with the pathophysiology using a larger scale multi-imaging modality and multi-time-point clinical study. Future studies should include the magnetization transfer ratio asymmetry results alongside the findings of the study to facilitate the comparison of results between different centers and also the published literature.
MATERIALS AND METHODS: We analyzed 46 histologically proven glioma (WHO grades II-IV) patients using standard 3T magnetic resonance imaging brain tumor protocol and IOP sequence. Lipid fraction was derived from the IOP sequence signal-loss ratio. The lipid fraction of solid nonenhancing region of glioma was analyzed, using a three-group analysis approach based on volume under surface of receiver-operating characteristics to stratify the prognostic factors into three groups of low, medium, and high lipid fraction. The survival outcome was evaluated, using Kaplan-Meier survival analysis and Cox regression model.
RESULTS: Significant differences were seen between the three groups (low, medium, and high lipid fraction groups) stratified by the optimal cut-off point for overall survival (OS) (p ≤ 0.01) and time to progression (p ≤ 0.01) for solid nonenhancing region. The group with high lipid fraction had five times higher risk of poor survival and earlier time to progression compared to the low lipid fraction group. The OS plot stratified by lipid fraction also had a strong correlation with OS plot stratified by WHO grade (R = 0.61, p < 0.01), implying association to underlying histopathological changes.
CONCLUSION: The lipid fraction of solid nonenhancing region showed potential for prognostication of glioma. This method will be a useful adjunct in imaging protocol for treatment stratification and as a prognostic tool in glioma patients.
CASE PRESENTATION: We report the case of a 37-year-old Chinese woman with primary Sjögren syndrome who presented with ataxia over 3 months associated with tremor of the limbs. Magnetic resonance imaging of the brain revealed bilateral cerebellar atrophy. Based on the presence of cerebellar signs with magnetic resonance imaging brain findings, she was diagnosed as cerebellar degeneration secondary to primary Sjögren syndrome. She was treated with methylprednisolone, hydroxychloroquine, and two cycles of monthly intravenous cyclophosphamide. Subsequently, she refused further treatment, and her neurological symptoms remained the same upon the last clinic review. Primary cerebellar degeneration is rarely associated with primary Sjögren syndrome. The pathogenesis of the neurological manifestations in primary Sjögren syndrome is unclear. Treatment involves corticosteroids and immunosuppressive agents with no consensus of a specific therapy for the management of primary Sjögren syndrome with central nervous system involvement.
CONCLUSIONS: Cerebellar degeneration is a rare presentation of primary Sjögren syndrome. Early diagnosis and treatment of this condition is needed to ensure a good outcome.
OBJECTIVE: We evaluated whether transorbital ACS modulates BOLD activity in early visual cortex using high-resolution 7 Tesla functional magnetic resonance imaging (fMRI).
METHODS: In this feasibility study transorbital ACS in the alpha range and sham ACS was applied in a random block design in five healthy subjects for 20 min at 1 mA. Brain activation in the visual areas V1, V2 and V3 were measured using 7 Tesla fMRI-based retinotopic mapping at the time points before (baseline) and after stimulation. In addition, we collected data from one hemianopic stroke patient with visual cortex damage after ten daily sessions with 25-50 min stimulation duration.
RESULTS: In healthy subjects transorbital ACS increased the activated cortical surface area, decreased the fMRI response amplitude and increased coherence in the visual cortex, which was most prominent in the full field task. In the patient, stimulation improved contrast sensitivity in the central visual field. BOLD amplitudes and coherence values were increased in most early visual areas in both hemispheres, with the most pronounced activation detected during eccentricity testing in retinotopic mapping.
CONCLUSIONS: This feasibility study showed that transorbital ACS modifies BOLD activity to visual stimulation, which outlasts the duration of the AC stimulation. This is in line with earlier neurophysiological findings of increased power in EEG recordings and functional connectivity reorganization in patients with impaired vision. Accordingly, the larger BOLD response area after stimulation can be explained by more coherent activation and lower variability in the activation. Alternatively, increased neuronal activity can also be taken into account. Controlled trials are needed to systematically evaluate the potential of repetitive transorbital ACS to improve visual function after visual pathway stroke and to determine the cause-effect relationship between neural and BOLD activity changes.
METHODS: A retrospective study of all NPSLE patients seen at the Pediatric Rheumatology Unit, Selayang Hospital from January 2004 to May 2017.
RESULTS: Twenty-eight (19.8%) of 141 JSLE patients had NPSLE with a median presenting age of 10 years (IQR 9 - 12), median follow-up of 7 years (IQR 4 - 11) and female: male ratio of 3.7:1. Twenty-three patients had single episodes of NPSLE and five patients had two distinct episodes each. The mean disease activity score (SLEDAI- 2K) was 24.9±11.8 at presentation with 81.8% having high disease activity (score > 12). Majority (60.6%) present with NPSLE within the first year of SLE diagnosis whilst the remainder occurred at a median of five years (IQR 3-7) post-SLE diagnosis. Majority (75.8%) had central nervous system (CNS) involvement commonly presenting with seizures, delirium and visual complaints whilst 24.2% had peripheral nervous system (PNS) involvement. Frequent accompanying features included hypocomplementemia, acute cutaneous lupus and lupus nephritis. Autoantibodies were common; ANA (100%), anti-dsDNA (78.8%) anti-RNP (39.4%) and anti-Sm (39.4%). Abnormalities were seen in 85.7% of the magnetic resonance imaging (MRI) studies performed, predominantly supratentorial white matter hyperintensities on T2 images whilst cerebrospinal fluid examination was normal in the majority. All patients with CNS involvement received corticosteroids with immunosuppressive therapy: Cyclophosphamide (20), Rituximab (2). Treatment for PNS involvement included corticosteroids with Azathioprine (6) or Mycophenolate mofetil (2). At 12 months post-NPSLE, majority (85.7%) recovered without any neurological sequelae.
CONCLUSIONS: Juvenile-onset NPSLE presents with a myriad of clinical features. It is associated with high disease activity and non-specific MRI features. With early diagnosis and treatment, the majority had good prognosis.