Faculty Bibliography

OBJECTIVE. The amount of cerebral white matter lesions (WMLs) and the severity of carotid artery disease are correlated in this study. The association between the severity of WMLs and the volume of the different components of carotid artery plaque is also evaluated. MATERIALS AND METHODS. Fifty consecutive patients (39 men, 11 women; mean [SD] age, 71 +/- 9 years) with carotid artery stenosis who underwent carotid endarterectomy were included in this study. On admission, patients underwent head and neck CT angiography (CTA) and brain MRI. The CTA-based plaque volume and the percentages of the three main plaque components (fatty, mixed, and calcified) were calculated according to the attenuation values. Leukoaraiosis lesion volume on FLAIR images was determined using a semiautomated segmentation technique. Pearson correlation was conducted between the leukoaraiosis lesion volume on FLAIR images and the volumes of the different plaque components. RESULTS. Pearson correlation analysis was performed to determine WML volume versus total carotid plaque volume (rho = 0.2531; p = 0.0262), fatty plaque volume (rho = 0.387; p = 0.0005), mixed plaque volume (rho = 0.1709; p = 0.15), and calcified plaque volume (rho = 0.0146; p = 0.899). The WML volume was also compared against fatty plaque percentage (rho = 0.343; p = 0.0018), mixed plaque percentage (rho = 0.181; p = 0.124), and calcified plaque percentage (rho = -0.209; p = 0.068). CONCLUSION. The cerebral WML volume and the total volume of the plaque are correlated. The amount of fat within the plaque is an additional risk factor, whereas the calcified component seems to be protective.

BACKGROUND AND PURPOSE: The spinal cord is a site of predilection for MS lesions. While diffusion tensor imaging is useful for the study of anisotropic systems such as WM tracts, it is of more limited utility in tissues with more isotropic microstructures (on the length scales studied with diffusion MR imaging) such as gray matter. In contrast, diffusional kurtosis imaging, which measures both Gaussian and non-Gaussian properties of water diffusion, provides more biomarkers of both anisotropic and isotropic structural changes. The aim of this study was to investigate the cervical spinal cord of patients with MS and to characterize lesional and normal-appearing gray matter and WM damage by using diffusional kurtosis imaging. MATERIALS AND METHODS: Nineteen patients (13 women, mean age = 41.1 +/- 10.7 years) and 16 controls (7 women, mean age = 35.6 +/- 11.2-years) underwent MR imaging of the cervical spinal cord on a 3T scanner (T2 TSE, T1 magnetization-prepared rapid acquisition of gradient echo, diffusional kurtosis imaging, T2 fast low-angle shot). Fractional anisotropy, mean diffusivity, and mean kurtosis were measured on the whole cord and in normal-appearing gray matter and WM. RESULTS: Spinal cord T2-hyperintense lesions were identified in 18 patients. Whole spinal cord fractional anisotropy and mean kurtosis (P = .0009, P = .003), WM fractional anisotropy (P = .01), and gray matter mean kurtosis (P = .006) were significantly decreased, and whole spinal cord mean diffusivity (P = .009) was increased in patients compared with controls. Mean spinal cord area was significantly lower in patients (P = .04). CONCLUSIONS: Diffusional kurtosis imaging of the spinal cord can provide a more comprehensive characterization of lesions and normal-appearing WM and gray matter damage in patients with MS. Diffusional kurtosis imaging can provide additional and complementary information to DTI on spinal cord pathology.

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.

Imaging of a 29-year-old man with seizures showed a frontal lobe mass with curvilinear narrow calcifications, cystic components and multiple flow-voids. An AVM was considered. A DSA confirmed the hypervascular nature of the lesion. It was resected and microscopic examination showed an anaplastic oligodendroglioma remarkable for a diffuse and hypertrophic vasculature with areas of frank vascular proliferation. The marked vascularity seen on the MRI, the gyriform calcifications and the cystic degeneration are all features which can be encountered in an AVM. This case illustrates that highly vascular malignant gliomas can simulate vascular lesions by radiology and may require an angiogram for diagnosis.

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.

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.

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.

OBJECTIVES: Examination of sensorimotor activation alone in multiple sclerosis (MS) patients may not yield a comprehensive view of cerebral response to task stimulation. Additional information may be obtained by examining the negative BOLD response (deactivation). Aim of this work was to characterize activation and deactivation patterns during passive hand movements in MS patients. METHODS: 13 relapsing remitting-MS patients (RRMS), 18 secondary progressive-MS patients (SPMS) and 15 healthy controls (HC) underwent an fMRI study during passive right-hand movements. Activation and deactivation contrasts in the three groups were entered into ANOVA, age and gender corrected. Post-hoc analysis was performed with one-sample and two-sample t-tests. For each patient we obtained lesion volume (LV) from both T1- and T2-weighted images. RESULTS: Activations showed a progressive extension to the ipsilateral brain hemisphere according to the group and the clinical form (HC

PMCID:3682993

PMID: 23799005

ISSN: 1932-6203

CID: 463902