Tatjana Stosic-Opincal

A multicenter assessment of cervical cord atrophy among MS clinical phenotypes.

Objective: In this multicenter study, a new semiautomatic method for segmenting the cervical cord from C2 to C5 was used to investigate the correlation between cord atrophy and clinical disability in a large sample of patients with multiple sclerosis (MS). Methods: T2 and 3-dimensional T1-weighted cervical cord scans and dual-echo brain scans were acquired from 143 healthy controls, 22 patients with clinically isolated syndromes (CIS), 101 patients with relapsing-remitting MS (RRMS), 79 patients with secondary progressive MS (SPMS), 58 patients with benign MS (BMS), and 75 patients with primary progressive MS (PPMS) in 3 European centers. Normalized cervical cord cross-sectional area (CSAn) was measured by an active surface cord model. Between-group comparisons were performed using linear mixed-effect models. A nonparametric kernel estimator was used to obtain smoothed plots of CSA along the cervical cord. Results: Cord CSAn was significantly lower in PPMS vs healthy controls, BMS vs RRMS, SPMS vs BMS, and RRMS. From C2 to C5, a net separation and definition of the plots of patients with BMS, PPMS, and SPMS was seen with respect to those of the other study groups. CSAn was correlated with Expanded Disability Status Scale (r = −0.49, p < 0.0001), with a differential effect among disease clinical phenotypes: no association in either CIS or in BMS; association in RRMS (r = −0.30, p = 0.001), SPMS (r = −0.34, p = 0.001), and PPMS (r = −0.27, p = 0.01). Conclusions: Cervical cord atrophy provides a relevant and useful marker for the characterization of clinical heterogeneity of patients with MS. The stability of this measure among different centers supports its use as potential outcome measure to monitor disease progression in multicenter trials.

MRI measurements of brainstem structures in patients with Richardson's syndrome, progressive supranuclear palsy-parkinsonism, and Parkinson's disease†

We investigated the diagnostic accuracy of brainstem MRI measurements in patients with different progressive supranuclear palsy (PSP) syndromes and Parkinsons disease (PD). Using 3D T1‐weighted images, midbrain, and pons areas, as well as superior (SCP) and middle cerebellar peduncle (MCP) widths were measured in 10 patients with Richardsons syndrome (PSP‐RS), 10 patients with PSP‐parkinsonism (PSP‐P), 25 patients with PD, and 24 healthy controls. The ratio between pons and midbrain areas (pons/midbrain), that between MCP and SCP widths (MCP/SCP), and the MR parkinsonism index ([pons/midbrain]*[MCP/SCP]) were calculated. The pons/midbrain and the MR parkinsonism index allowed to differentiate PSP‐RS from PD with high sensitivity (90%, 100%), specificity (96%, 92%), and accuracy (94%, 97%). Only the pons/midbrain was found to distinguish PSP‐P from PD, but with a lower diagnostic accuracy (sensitivity = 60%, specificity = 96%, accuracy = 86%). Compared to PSP‐RS, PSP‐P experience a relatively less severe involvement of infratentorial brain. The pons/midbrain looks as a promising measure in the differentiation of individual PSP‐P from PD patients.

Intrinsic damage to the major white matter tracts in patients with different clinical phenotypes of multiple sclerosis: A voxelwise diffusion-tensor MR study

PURPOSE To apply voxelwise analysis of diffusion-tensor (DT) magnetic resonance (MR) tractography and T2-weighted MR lesion measurements to characterize intrinsic damage to the brain white matter (WM) tracts and the relation of this damage to the presence and location of focal lesions among the main clinical phenotypes of multiple sclerosis (MS). MATERIALS AND METHODS The study was conducted with institutional review board approval. Written informed consent was obtained from each participant. Brain dual-echo and DT MR images were obtained in 172 patients with MS (22 [13%] with clinically isolated syndromes [CIS] suggestive of MS, 51 [30%] with relapsing-remitting [RR] MS, 44 [26%] with secondary progressive MS, 20 [12%] with benign MS, 35 [20%] with primary progressive MS) and 46 healthy control subjects. Probability maps of the major brain WM tracts were produced. Between-group comparisons were assessed by using analysis of covariance. RESULTS Compared with the healthy control subjects, the patients with CIS had significantly increased (P < .001) mean diffusivity, axial diffusivity, and radial diffusivity in the majority of WM tracts. The primary progressive MS group showed diffuse increases in mean, axial, and radial diffusivity, with fractional anisotropy (FA) damage involving the majority of WM tracts. No relevant difference in diffusivity measures was found between the CIS and RR-MS groups. Compared with the benign MS group, the RR-MS group had reduced FA values in all WM tracts and decreased axial diffusivity in the majority of tracts. The secondary progressive MS group had pronounced damage to the majority of tracts and, compared with the benign MS group, pronounced FA alteration of the tracts relevant for motor impairment. CONCLUSION Voxelwise assessment of DT MR index abnormalities is a rewarding strategy for understanding the heterogeneity of clinical MS phenotypes.

Wallerian and trans-synaptic degeneration contribute to optic radiation damage in multiple sclerosis: a diffusion tensor MRI study

Background: Optic radiation (OR) damage occurs in multiple sclerosis (MS). Objectives: The purpose of this study was to explore the contribution of local and distant mechanisms associated with OR damage in MS. Methods: Diffusion tensor (DT) magnetic resonance imaging (MRI) tractography probability maps of the ORs were derived from 102 MS patients and 11 controls. Between-group differences of OR normal-appearing white matter (NAWM) damage and topographical distribution of OR damage were assessed using quantitative and voxel-wise analyses, considering the influence of previous optic neuritis (ON+) and T2 OR lesions (T2 OR+). Results: OR NAWM diffusivity abnormalities were more severe in ON+ patients vs patients without previous optic neuritis (ON–) and T2 OR+ vs T2 OR– patients. Damage to the anterior portions of the ORs was more severe in ON+ vs ON– patients. Compared to controls and T2 OR– patients, T2 OR+ patients experienced a more distributed pattern of DT MRI abnormalities along the ORs, with an increased axial diffusivity limited to the anterior portions of the ORs. In T2 OR+ group, ON+ vs ON– patients showed DT MRI abnormalities in the middle portion of the ORs, in correspondence with focal lesions. OR damage correlated with OR T2 lesion volume, visual dysfunction and optic nerve atrophy. Conclusions: Both trans-synaptic degeneration secondary to optic nerve damage and Wallerian degeneration due to local T2 lesions contribute to OR damage in MS.

Relationship between Damage to the Cerebellar Peduncles and Clinical Disability in Multiple Sclerosis

PURPOSE To assess whether a structural disconnection between the cerebellum and the cerebral hemispheres contributes to cerebellar and brainstem symptoms in multiple sclerosis (MS). MATERIALS AND METHODS This study was approved by the local ethics committee, and written informed consent was obtained from each participant. Brain T2 lesion load, cerebellar white matter and gray matter volumes, and tract-specific measures of the middle and superior cerebellar peduncles were derived from 172 patients with MS and 46 control subjects. Predictors of clinical impairment, which was determined at ambulation and with cerebellar and brainstem functional system scores, were identified by using random forest analysis. RESULTS Of the 172 patients, 112 (65%) had middle cerebellar peduncle T2 lesions and 74 (43%) had superior cerebellar peduncle T2 lesions. T2 lesions in the middle and superior cerebellar peduncles were more common in clinically impaired patients than in unimpaired patients (P = .05 to <.0001). Most conventional magnetic resonance imaging metrics were more abnormal in impaired patients than in unimpaired patients (P = .03 to <.0001). Except for axial diffusivity, diffusivity abnormalities of the middle and superior cerebellar peduncles were more severe in clinically impaired patients than in unimpaired patients (P = .04 to <.0001). A minimal overlap was found between diffusivity abnormalities and T2 lesions. Compared with volumetric measures of T2 lesions or cerebellar atrophy, diffusivity measures of middle or superior cerebellar peduncle damage enabled better differentiation between clinically impaired and unimpaired patients (C statistics: 61%-70%). CONCLUSION The assessment of middle and superior cerebellar peduncle damage contributes to the explanation of cerebellar and/or brainstem symptoms and ambulatory impairment in MS.

Voxel-wise mapping of cervical cord damage in multiple sclerosis patients with different clinical phenotypes

Objective To apply voxel-based methods to map the regional distribution of atrophy and T2 hyperintense lesions in the cervical cord of multiple sclerosis (MS) patients with different clinical phenotypes. Methods Brain and cervical cord 3D T1-weighted and T2-weighted scans were acquired from 31 healthy controls (HC) and 77 MS patients (15 clinically isolated syndromes (CIS), 15 relapsing-remitting (RR), 19 benign (B), 15 primary progressive (PP) and 13 secondary progressive (SP) MS). Hyperintense cord lesions were outlined on T2-weighted scans. The T2- and 3D T1-weighted cord images were then analysed using an active surface method which created output images reformatted in planes perpendicular to the estimated cord centre line. These unfolded cervical cord images were co-registered into a common space; then smoothed binary cord masks and lesion masks underwent spatial statistic analysis (SPM8). Results No cord atrophy was found in CIS patients versus HC, while PPMS had significant cord atrophy. Clusters of cord atrophy were found in BMS versus RRMS, and in SPMS versus RRMS, BMS and PPMS patients, mainly involving the posterior and lateral cord segments. Cord lesion probability maps showed a significantly greater likelihood of abnormalities in RRMS, PPMS and SPMS than in CIS and BMS patients. The spatial distributions of cord atrophy and cord lesions were not correlated. In progressive MS, regional cord atrophy was correlated with clinical disability and impairment in the pyramidal system. Conclusions Voxel-based assessment of cervical cord damage is feasible and may contribute to a better characterisation of the clinical heterogeneity of MS patients.

Clinically Isolated Syndrome Suggestive of Multiple Sclerosis: Dynamic Patterns of Gray and White Matter Changes-A 2-year MR Imaging Study.

PURPOSE To investigate the patterns of regional gray matter (GM) and white matter (WM) atrophy, WM microstructural tissue damage, and changes in patients with a clinically isolated syndrome (CIS) suggestive of multiple sclerosis at 2 years from clinical onset. MATERIALS AND METHODS Institutional review board approval and written informed consent from all patients were obtained. Neurologic assessment and conventional, diffusion-tensor, and volumetric brain MR imaging sequences were performed in 37 patients with CIS within 2 months of clinical onset, and after 3, 12, and 24 months. Fourteen healthy control subjects also were studied. Longitudinal GM and WM volume changes and WM microstructural abnormalities were assessed by using voxel-based morphometry (P < .001, uncorrected) and tract-based spatial statistics (P < .05, corrected). RESULTS At 24 months, 33 of 37 (89%) patients had developed multiple sclerosis. At month 3, patients with CIS showed a transient volume increase in frontal, parietal, temporal, and cerebellar GM regions. At 12 months, patients with CIS developed atrophy of the thalami, caudate nuclei, cerebellum, and frontal, parietal, and temporal lobes. At 24 months GM volume of the frontal, temporal, and parietal cortical areas further decreased from that at 12 months. WM atrophy involved only a few WM regions at 2 months from clinical onset, with progressive involvement of additional WM tracts with time. A diffuse pattern of WM microstructural abnormalities was detected within 2 months of onset and had worsened at 24 months. CONCLUSION After an acute inflammatory event, dynamic modifications of regional GM and WM damage occur in patients with CIS, with a progressive evolution of WM damage from disease onset and a transient, early increase in GM volume, followed by GM atrophy. Neurodegenerative processes start early in patients with multiple sclerosis.

Neuroimaging of Spinal Tumors

Intradural tumors are relatively rare neoplasms; however, when unrecognized in a timely manner, they can result in serious deficits and disability. These tumors lack obvious clinical symptoms until compression of the cord or neurologic deficits occur. The most common intramedullary lesions are ependymomas, astrocytomas, and hemangioblastomas. Meningiomas and nerve sheath tumors (schwannomas and neurofibromas) comprise most intradural-extramedullary tumors. Less common tumors are hemangiopericytoma, paraganglioma, melanocytoma, melanoma, metastases, and lymphoma. MR imaging is the imaging method of choice, helpful for localization and characterization of these lesions before treatment and for follow-up after treatment.

The role of magnetic resonance imaging in the diagnosis of postoperative spondylodiscitis.

BACKGROUND Spondylodiscitis, discitis associated with vertebral osteomyelitis may follow disc-removal surgery. A targeted successful treatment of spinal infections requires clinical and laboratory data that are completed by the contribution of imaging procedures. Neuroimaging provides precise information on correct topography, localization, propagation, and differential diagnosis of spinal infectious lesions. The aim of this study was to present magnetic resonance imaging (MRI) findings in patients with postoperative spondylodiscitis. METHODS MRI was performed in 6 patients aged 29-50, with clinically suspected postoperative spondylodiscitis. Initial examination was performed 3-8 weeks after surgery and 3, 6, or 12 months after the treatment by antibiotics. Patients underwent MRI on a IT imaging unit (Siemens, Magnetom-Impact), including sagittal T1W and T2W images and axial T1W images before and after the administration of gadolinium contrast medium. RESULTS MRI findings included: significantly decreased signal intensity with the loss of distinction between vertebral body and intervertebral disc space on T1W, increased signal intensity in the adjacent vertebral body and end-plates on T2W, contrast enhancement of vertebral body and disc space and paravertebral soft tissue changes. Follow-up examinations performed 3, 6, or 12 months after the treatment showed less abnormal signal intensities on both T1- and T2-weighted images. CONCLUSION Postoperative spondylodiscitis is a rare but severe complication of lumbar disc surgery. Since conventional imaging techniques are not reliable for detecting spondylodiscitis in its early stages, MRI is of great significance in the diagnosis of postoperative spondylodiscitis.

Significance of magnetic resonance imaging in differential diagnosis of nontraumatic brachial plexopathy.

BACKGROUND/AIM Nontraumatic brachial plexopathies may be caused by primary or secondary tumors, radiation or inflammation. The aim of this study was to present the significance of MRI in revealing the cause of nontraumatic brachial plexopathy. METHODS A two-year retrospective study included 22 patients with nontraumatic brachial plexopathy. In all the patients typical clinical findings were confirmed by upper limb neurophysiological studies. In all of them MRI of brachial plexus was performed by 1.5 T scanner in T1 and T1 FS sequence with and without contrast, as well as in T2 and T2 FS sequences. RESULTS Seven (32%) patients had brachial plexopathy with signs of inflammatory process, 5 (23%) patients had secondary tumors, in 4 (18%) patients multifocal motor neuropathy was established and in the same number (18%) of the patients postradiation fibrosis was found. Two patients (9%) had primary neurogenic tumors. CONCLUSION According to the results of this study MRI is a method which may determine localization and cause of brachial plexopathy. MRI can detect focal nerve lesions when other methods fail to find them. Thus, MRI has a direct impact on further diagnostic and therapeutical procedures.