MRI T2 hypointensity of the dentate nucleus is related to ambulatory impairment in multiple sclerosis

OBJECTIVES: MRI T2 hypointensity in multiple sclerosis (MS) gray matter, suggesting iron deposition, is associated with physical disability, disease course, lesion load, and brain atrophy. Ambulatory dysfunction limits quality of life; however correlation with conventional MRI remains poor. METHODS: Normalized intensity on T2-weighted images was obtained in the basal ganglia, thalamus, red nucleus, and dentate nucleus in 47 MS patients and 15 healthy controls. Brain T1-hypointense and FLAIR-hyperintense lesion volume, third ventricle width, brain parenchymal fraction and timed 25 foot walk (T25FW) were measured in the MS group. RESULTS: T2 hypointensity was present throughout gray matter in MS vs. controls (all p<0.01). Dentate T2 hypointensity was the only MRI variable significantly correlated with T25FW (Pearson r=-0.355, p=0.007) and was also the best MRI correlate of physical disability (EDSS) score in regression modeling (r=-0.463, R(2)=0.223, p=0.004). CONCLUSIONS: T2 hypointensity is present in subcortical gray matter nuclei in patients with MS vs. normal controls. Dentate nucleus T2 hypointensity is independently related to ambulatory impairment and disability, accounting for more variance than conventional lesion and atrophy measures. This study adds more weight to the notion that T2 hypointensity is a clinically relevant marker of tissue damage in MS.     

Interhemispheric asymmetry of brain diffusivity in normal individuals: a diffusion-weighted MR imaging study

BACKGROUND AND PURPOSE: Previous neuroimaging studies have suggested asymmetries in brain diffusivity may exist. The purpose of this study was to assess whether water diffusivity in deep gray matter structures shown by diffusion-weighted (DW) imaging differs between the right and left cerebral hemispheres in normal individuals. METHODS: Brain MR imaging was obtained in 23 healthy volunteers. A multisection image without diffusion weighting, and images with weighting applied in the read, phase, and section directions with a b-factor of 1000 s/mm(2) were collected. Diffusivity was computed separately in each direction, and the results were averaged to form mean diffusivity maps. Quantitative diffusivity values were obtained from the globus pallidus, putamen, caudate, thalamus, white matter, and CSF by using a standardized region of interest template. Interhemispheric differences were assessed by using a paired sample t test. RESULTS: Mean diffusivity was higher in the: left (mean +/- SD: 0.689 x 10(-3)+/- 0.069 x 10(-3)mm(2)/s) versus right (0.642 x 10(-3)+/- 0.071 x 10(-3)mm(2)/s) caudate (% difference, P value: 7.0%, P = .001); right (0.745 x 10(-3)+/- 0.053 x 10(-3)mm(2)/s) versus left (0.706 x 10(-3)+/- 0.050 x 10(-3)mm(2)/s) globus pallidus (5.2%, P < .001); left (0.720 x 10(-3)+/- 0.059 x 10(-3)mm(2)/s) versus right (0.674 x 10(-3)+/- 0.052 x 10(-3)mm(2)/s) putamen (6.4%, P < .001); right (0.750 x 10(-3)+/- 0.040 x 10(-3)mm(2)/s) versus left (0.716 x 10(-3)+/- 0.031 x 10(-3)mm(2)/s) thalamus (4.5%, P < .001). No significant right versus left difference was seen in the CSF (P = .291), anterior frontal white matter (P = .834), or centrum semiovale (P = .320). CONCLUSION: Gray matter diffusivity may differ between hemispheres of the brain in healthy individuals. Analysis of deep gray matter lesions requires caution, as statistically significant interhemispheric differences may not always be indicative of disease.     

A new technique for correction of disproportionate preputial growth with phimosis

A new surgical solution to correct the rare anomaly of asymmetric phimosis is described, with a note on its symptomatology and etiopathogenesis.     

Spinal adrenal cortical adenoma with oncocytic features: report of the first intramedullary case and review of the literature

Ectopic adrenal cortical neoplasms are extremely rare, and only a few have involved the CNS. We report the first case of an intramedullary oncocytic adrenal cortical neoplasm of the spinal cord with immunohistochemical (IMHC) confirmation. A 27-year-old man presented with progressive lower extremity weakness, spastic paraparesis, decreased reflexes, and hypoesthesia below T10. A spinal myelogram showed cauda equina blockade and obliteration of sacral nerve roots. This prompted emergent surgical intervention. A well-circumscribed, approximately 3 x 2 cm, light brown to tan, intramedullary tumor was identified at the level of the conus medullaris. Histologically, the tumor showed sheets and nests of plump, cytologically bland polygonal cells with abundant eosinophilic cytoplasm. A single mitosis, but no necrosis, was identified. By IMHC, the cells were positive for inhibin, melan-A, and synaptophysin, and negative for GFAP, EMA, cytokeratins, S-100, HMB-45, and chromogranin. Electron microscopy study performed from paraffin-embedded tissues demonstrated abundant mitochondria, and lipid vacuoles. This case confirms the occurrence of adrenal cortical neoplasms in the CNS and is the first report of an intradural, intramedullary adrenal cortical adenoma of the spinal cord, and the first to occur in a male. This tumor should be considered in the differential diagnosis of tumors of the CNS.     

Special populations: The management of seizures in HIV-positive patients

An increasing percentage of patients with new-onset seizures are HIV positive. The evaluation and management is distinctly different from managing the non-HIV-infected patient. Clinicians must be familiar with comorbid infectious etiologies and the relative value of electroencephalogram, imaging, and serum and cerebrospinal fluid laboratory tests. Traditional antiepileptic drug (AED) therapies are contraindicated and may lead to increased HIV viral replication through either directed cellular mechanisms or interference with antiretroviral therapies. Newer AEDs have pharmacokinetic properties that make them reasonable choices, although none have been specifically studied for efficacy or safety in HIV. Lastly, optimal choice of an AED should reflect commonly encountered neurologic and psychiatric comorbidities.     

Short-term brain atrophy changes in relapsing-remitting multiple sclerosis

The objective of this study was to establish whether the time interval of 3 months is sufficient to detect whole-brain atrophy changes in patients with relapsing-remitting (RR) multiple sclerosis (MS). Another aim was to assess the value of monthly gadolinium (Gd)-enhanced magnetic resonance imaging (MRI) and of different Gd-enhancement patterns as predictors of brain atrophy. Thirty patients with RRMS (mean disease duration 4.9 years, mean age 34.4 years and mean Expanded Disability Status Scale [EDSS] 1.4) were assessed at baseline and monthly for a period of 3 months with clinical and MRI examinations. Calculations of baseline and monthly absolute and percent changes of MRI measures have been obtained using two semiautomated (Buffalo and Trieste) and one automated (SPM99) segmentation method. Changes of brain parenchymal fraction (BPF) were investigated according to Gd-enhancement patterns. Mean absolute and percent changes of BPF did not significantly differ at any time point in the study for any of the three methods. There was slight but not significant decrease of BPF from baseline to month 3: -0.0004 (0.05%), p=0.093 for Trieste; -0.0006 (0.07%), p=0.078 for Buffalo; and -0.0006 (0.08%), p=0.081 for SPM99 method. In ring-enhancement positive patients, there was a significant difference between baseline and month 3 changes of BPF, EDSS, and number of relapses. Over the study period, we did not demonstrate differences between changes of BPF according to the presence of Gd enhancement. Longitudinally, multiple regression analysis demonstrated that the only clinical or MRI parameter that predicted BPF decrease was the mean absolute change of ring-enhancing lesion load (R=0.62, p=0.003). The noteworthy findings of this study are (1) the observation that a significant brain atrophy progression cannot be detected over a 3-month period in RRMS; (2) the demonstration that the ring-enhancement pattern may contribute to more severe brain tissue loss in the short term; and (3) the lack of relationship between the presence and duration of Gd-enhancement activity and brain volume changes in the short term.