Faculty Bibliography

BACKGROUND: Multiple sclerosis (MS) is characterized by demyelinating and degenerative processes within the central nervous system. Unlike conventional MRI,new advanced imaging techniques improve pathological specificity and better highlight the relationship between anatomical damage and clinical impairment. OBJECTIVE: To investigate the relationship between clinical disability and both grey (GM) and white matter (WM) regional damage in MS patients. METHODS: Thirty-six relapsing remitting-MS patients and 25 sex- and age-matched controls were enrolled. All patients were clinically evaluated by the Expanded Disability Status Scale and the Multiple Sclerosis Functional Composite (MSFC) scale, which includes the 9-hole peg test (9HPT), the timed 25-feet walking test (T25FW) and the paced auditory serial addition test (PASAT). All subjects were imaged by a 3.0 T scanner: dual-echo fast spin-echo, 3DT1-weighted and diffusion-tensor imaging (DTI) sequences were acquired. Voxel-based morphometry (VBM) and tract-based spatial statistics (TBSS) analyses were run for regional GM and WM assessment, respectively. T2 lesion volumes were also calculated, by using a semi-automated technique. RESULTS: Brain volumetric assessment of GM and DTI measures revealed significant differences between patients and controls. In patients, different measures of WM damage correlated each-other (p<0.0001), whereas none of them correlated with GM volume. In patients, focal GM atrophy and widespread WM damage significantly correlated with clinical measures. In particular, VBM analysis revealed a significant correlation (p<0.05) between GM volume and 9HPT in cerebellum and between GM volume and PASAT in orbito-frontal cortex. TBSS showed significant correlations between DTI metrics with 9HPT and PASAT scores in many WM bundles (p<0.05), including corpus callosum, internal capsule, posterior thalamic radiations, cerebral peduncles. CONCLUSIONS: Selective GM atrophy and widespread WM tracts damage are associated with functional impairment of upper-limb motion and cognition. The combined analysis of volumetric and DTI data may help to better understand structural alterations underlying physical and cognitive dysfunction in MS.

Diffusion-weighted magnetic resonance imaging is based on the Brownian motion of water and enables quantification of the apparent diffusion coefficient throughout the body. This article discusses the principles of diffusion-weighted magnetic resonance imaging, as well as the possible applications and limitations as they apply to liver imaging. This will introduce the readers to this novel magnetic resonance imaging tool, which has a promising future.

Purpose:To combine two unbiased (ie, without any a priori hypothesis) magnetic resonance (MR) imaging processing approaches, tract-based spatial statistics and voxel-based morphometry, to investigate the relationship between white matter and gray matter damage and computer-based measures of balance impairment assessed at static posturography in patients with multiple sclerosis (MS).Materials and Methods:Institutional review board approval and written informed consent were obtained. Forty-five ambulatory patients with MS (34 women, 11 men) and 25 sex- and age-matched healthy control subjects were assessed by using a force platform to compute the displacement (in millimeters) of the body center of pressure in 30 seconds. In a separate session, patients underwent MR imaging at 3 T, including a dual-echo fast spin-echo sequence, a T1-weighted volume sequence, and a diffusion-tensor imaging sequence. T2 lesion volumes were assessed by using a semiautomated technique. Tract-based spatial statistics and voxel-based morphometry were used for the white and gray matter analyses, respectively, to correlate force platform measures with diffusion-tensor imaging parameters and regional gray matter volumes, adjusting for the patients' sex, age, disease duration, and lesion volume.Results:Patients with MS had worse postural stability, widespread alterations in most white matter bundles, and gray matter atrophy in several brain regions compared with control subjects. In patients with MS, balance impairment was correlated with worse diffusion-tensor imaging parameters along the cerebellar connections and supratentorial associative white matter bundles (P < .05, threshold-free cluster enhancement corrected). Gray matter atrophy of the superior lobules of the cerebellum (IV, V, VI), and lobules VIII also correlated with worse posturometric values (P < .05, family-wise error corrected).Conclusion:Imbalance due to MS appears to be related to the disconnection between the spinal cord, cerebellum, and cerebral cortex, which in turn produces atrophy of the sensory motor cerebellar regions that are functionally connected with specific cortical areas.(c) RSNA, 2013.

The Cavum Septi Pellucidi (CSP), Cavum Vergae (CV) and Cavum Veli Interpositi, are anatomical variants located in the midline of the brain. It is important to identify these conditions to distinguish them from other entities that may require treatment. In this paper, our purpose is to describe MR and CT findings of CSP, CV and Cavum Veli Interpositi, explaining the differential diagnosis.

BACKGROUND AND PURPOSE: Trigeminal nerve injury or dysfunction is associated with denervation atrophy of muscles innervated by the mandibular branch of the trigeminal nerve. The purpose of our study was to evaluate the association between chronic CN V denervation and parotid gland atrophy. MATERIALS AND METHODS: Twenty-six patients with chronic masticator muscle atrophy were retrospectively identified and evaluated for the presence of ipsilateral parotid gland atrophy. Twenty-six age-matched control subjects with no clinical or imaging evidence of chronic masticator space atrophy were also identified. Segmentation of the parotid gland was performed to calculate a parotid asymmetry index. The Fisher exact test and t test were respectively used to determine the correlation between parotid gland atrophy and ipsilateral masticator muscle atrophy and to evaluate any difference in the size of the involved parotid gland when compared with that in the control subjects. RESULTS: Ipsilateral parotid gland atrophy was seen in 9/26 (42.8%) patients with fatty replacement of the masticator group of muscles, suggesting a correlation between parotid gland atrophy and CN V denervation (P < .001). The parotid asymmetry index was significantly different in patients with CN V denervation (0.59 +/- 0.25) compared with control subjects (0.92 +/- 0.03) (P < .001). CONCLUSIONS: Ipsilateral parotid gland atrophy can accompany chronic CN V denervation change, and its clinical significance remains to be determined.