Faculty Bibliography

BACKGROUND AND PURPOSE: Experimental studies have suggested a role for iron accumulation in the pathology of TBI. Magnetic field correlation MR imaging is sensitive to the presence of non-heme iron. The aims of this study are to 1) assess the presence, if any, and the extent of iron deposition in the deep gray matter and regional white matter of patients with mTBI by using MFC MR imaging; and 2) investigate the association of regional brain iron deposition with cognitive and behavioral performance of patients with mTBI. MATERIALS AND METHODS: We prospectively enrolled 28 patients with mTBI. Eighteen healthy subjects served as controls. The subjects were administered the Stroop color word test, the Verbal Fluency Task, and the Post-Concussion Symptoms Scale. The MR imaging protocol (on a 3T imager) consisted of conventional brain imaging and MFC sequences. After the calculation of parametric maps, MFC was measured by using a region of interest approach. MFC values across groups were compared by using analysis of covariance, and the relationship of MFC values and neuropsychological tests were evaluated by using Spearman correlations. RESULTS: Compared with controls, patients with mTBI demonstrated significant higher MFC values in the globus pallidus (P = .002) and in the thalamus (P = .036). In patients with mTBI, Stroop test scores were associated with the MFC value in frontal white matter (r = -0.38, P = .043). CONCLUSIONS: MFC values were significantly elevated in the thalamus and globus pallidus of patients with mTBI, suggesting increased accumulation of iron. This supports the hypothesis that deep gray matter is a site of injury in mTBI and suggests a possible role for iron accumulation in the pathophysiological events after mTBI

BACKGROUND: Little is known about the cortical activation changes during clinical relapses in multiple sclerosis (MS). OBJECTIVE: To assess cross-sectional and longitudinal differences in functional magnetic resonance imaging (fMRI) cortical patterns between the relapsing and stable phases of MS. METHODS: We studied 32 patients with relapsing-remitting MS with mild disability: 19 within 48 h of symptom onset of a new relapse (G1) and 13 in the stable phase, relapse-free for at least 6 months (G2). All patients underwent fMRI twice, upon entry (time 1) and 30-50 days later (time 2), during right-hand movement. RESULTS: No between-group differences were observed in age, disability or T2 lesion load. Between-group analysis showed a significant difference in the ipsilateral precentral gyrus (IPG) activation at time 1. Activity differences in the IPG expressed reduced deactivation in G1 compared with G2. Longitudinal changes in brain activity in the IPG were significantly greater in G1 than G2. G1 patients with a slow clinical recovery (n = 8) showed different activity at baseline and greater activity changes over time in the IPG than patients with a fast recovery (n = 11). CONCLUSION: This study shows that the relapsing phase is associated with reduced brain deactivation in the IPG, which is more marked in patients with a slow clinical recovery. Increased cortical excitability associated with inflammation may determine functional modifications within the ipsilateral motor area.

Lymphomatosis cerebri (LC) is a rare form of primary central nervous system lymphoma; we report a case of LC mainly involving the brainstem and cerebellum. This diagnosis should be considered in patients presenting with diffuse white matter disease, and a subacute clinical history of cognitive deficits, ataxic gait, and personality changes. We present our findings along with a review of the neuroradiological literature.

Functional MRI is a new and exciting tool enabling non-invasive assessment of renal function. Diffusion-weighted imaging (DWI), diffusion tensor imaging (DTI), blood oxygen level-dependent (BOLD) MRI, and magnetic resonance elastography (MRE) are some of the techniques under investigation. In this article we review the basic principles of these techniques, their possible applications, and their limitations

PURPOSE: To assess, by means of magnetic resonance (MR) imaging, the longitudinal changes in white matter (WM) and gray matter (GM) in a cohort of patients with clinically isolated syndrome (CIS) who were followed up for 1 year. MATERIALS AND METHODS: This prospective, HIPAA-compliant study was approved by the institutional review board. Written informed consent was obtained from all the participants. Changes in GM and WM integrity were respectively investigated by using three-dimensional T1-weighted and diffusion-tensor (DT) imaging sequences and by applying voxel-based morphometry (VBM) and tract-based spatial statistics (TBSS) analyses. Thirty-four consecutive patients (21 women, 13 men; mean age, 32.8 years +/- 7.7 [standard deviation]) who had CIS were recruited. All the patients underwent a neurologic and an MR examination at baseline and 12 months later; the MR examination consisted of three-dimensional T1-weighted dual-echo turbo spin-echo DT imaging. VBM and TBSS were used to analyze GM volume and WM fractional anisotropy, respectively. RESULTS: After 1 year, multiple sclerosis (MS) was diagnosed in 33 (97%) of 34 patients with CIS. Longitudinal volumetric analysis revealed a significant (P < .001) reduction in global GM volume. The VBM analysis showed the development of regional GM atrophy involving several cortical and subcortical regions in both hemispheres (P < .05). No significant longitudinal change in global or regional WM fractional anisotropy was otherwise observed. CONCLUSION: WM damage was detectable early and involved most fiber tracts in patients with MS, but it did not worsen significantly during the 1st year after clinical onset. In contrast, GM damage was not detectable at the time of clinical onset, but a significant decrease in cortical and deep GM volume was observed at 1 year.

A 35-year-old man presented with one month history of vomitus, dizziness and headache. CT and MR imaging revealed a 3.5 x 3.2 cm solitary extra-axial midline mass arising from the frontal falx cerebri; radiological findings were diagnostic of meningioma of the falx. At surgery, the tumour appeared as an extra-axial lesion and was removed via a left midline frontal craniotomy. Macroscopically, the surgical specimen was whitish, soft, well circumscribed and measured 1.6 cm in diameter; microscopic features showed a neoplasm with high cellularity, presence of mitotic figures, without necrosis or microvascular proliferation; the neoplasm was reactive for glial fibrillary acidic protein and MIB-1 index was about 15%. Given the localization, microscopic features were diagnostic of primary intracranial solitary leptomeningeal astrocytoma (PLA), WHO grade 3. PLA is a very rare lesion that arises in the leptomeninges of the brain or spinal cord with no involvement of intraparenchymatous tissue. Fifteen cases of PLA are reported in the literature. Retrospective neuroradiological analysis of this case failed to detect any findings to help in the differential diagnosis, thus confirming the fundamental role of the neuropathologist even in what can firstly appear to be a straightforward radiological diagnosis.

We describe a case of neuroplasticity associated with both arteriovenous malformation (AVM) and stroke, which occurred in two successive events in the same patient. Functional magnetic resonance imaging (fMRI) during right-hand movement in a young man with a left rolandic AVM detected activation of a region corresponding to the left premotor cortex. The AVM was embolized. A few hours after the last embolization session, the patient sustained an ischemic complication in the left subcortical white matter. A second fMRI detected a lower degree of left premotor cortex activation and strong activation of the contralesional right primary motor cortex and bilateral supplementary motor areas. One month later, in association with clinical recovery, the fMRI activation returned to that observed in the first fMRI, ie, selective activation of the ipsilesional left premotor cortex. This is, to our knowledge, the first description of two distinct functional cortical changes determined by an AVM and a stroke within the motor network.

PURPOSE: To quantify white matter (WM) and gray matter (GM) damage in patients who presented with clinically isolated syndrome (CIS), which is suggestive of multiple sclerosis (MS), by combining volume-based morphometry (VBM) and tract-based spatial statistics (TBSS). MATERIALS AND METHODS: This prospective HIPAA-compliant study was approved by the institutional review board. Written informed consent was obtained from all participants. In this study, 34 consecutive patients (21 women, 13 men; mean age, 31.7 years +/- 7.7 [standard deviation]) who presented with CIS were recruited. The magnetic resonance (MR) examination included dual-echo fast spin-echo, three-dimensional T1, and diffusion-tensor imaging. Sixteen matched healthy volunteers served as control subjects. T2 lesion volumes were assessed with a semiautomatic technique. VBM and TBSS were used for the GM and WM analyses, respectively, to compare regional GM volumes and fractional anisotropy (FA) values in the two groups. RESULTS: TBSS analysis revealed a pattern of diffuse FA reductions in patients with CIS at the cluster level (P < .05). Regions of decreased FA involved most of the WM pathways, including the corticospinal tracts, corpus callosum, and superior and inferior longitudinal fasciculi. There were no significant differences between the two groups in terms of global GM, WM, or cerebrospinal fluid volume or in terms of regional GM volume. CONCLUSION: Diffuse WM damage not accompanied by any change in GM or WM volume is observed in patients with CIS. This suggests that WM involvement plays a relevant role in the early phases of MS. Subsequently detected GM damage may be secondary to WM alterations.

Conventional neuroradiological techniques, such as computed tomography (CT) and magnetic resonance imaging (MRI), make a fundamental contribution in both the acute and chronic phases of stroke. Recent years have witnessed the development of new imaging modalities, which include diffusion-weighted imaging (DWI), perfusion-weighted imaging (PWI), CT-angiography (CTA), MR-angiography (MRA), magnetic resonance spectroscopy (MRS), diffusion tensor imaging (DTI) and functional MRI (fMRI). While CTA, MRA, DWI and PWI are commonly used for clinical purposes, DTI, MRS and fMRI are becoming increasingly important in the field of experimental research of cerebrovascular diseases, but are still far from becoming of primary usefulness in the everyday clinical setting.