A cross-species proteomic map reveals neoteny of human synapse development.

The molecular mechanisms and evolutionary changes accompanying synapse development are still poorly understood1,2. Here we generate a cross-species proteomic map of synapse development in the human, macaque and mouse neocortex. By tracking the changes of more than 1,000 postsynaptic density (PSD) proteins from midgestation to young adulthood, we find that PSD maturation in humans separates into three major phases that are dominated by distinct pathways. Cross-species comparisons reveal that human PSDs mature about two to three times slower than those of other species and contain higher levels of Rho guanine nucleotide exchange factors (RhoGEFs) in the perinatal period. Enhancement of RhoGEF signalling in human neurons delays morphological maturation of dendritic spines and functional maturation of synapses, potentially contributing to the neotenic traits of human brain development. In addition, PSD proteins can be divided into four modules that exert stage- and cell-type-specific functions, possibly explaining their differential associations with cognitive functions and diseases. Our proteomic map of synapse development provides a blueprint for studying the molecular basis and evolutionary changes of synapse maturation.

Asymmetric organelle positioning during epithelial polarization of C. elegans intestinal cells.

While the epithelial cell cortex displays profound asymmetries in protein distribution and morphology along the apico-basal axis, the extent to which the cytoplasm is similarly polarized within epithelial cells remains relatively unexplored. We show that cytoplasmic organelles within C. elegans embryonic intestinal cells develop extensive apico-basal polarity at the time they establish cortical asymmetry. Nuclei and conventional endosomes, including early endosomes, late endosomes, and lysosomes, become polarized apically. Lysosome-related gut granules, yolk platelets, and lipid droplets become basally enriched. Removal of par-3 activity does not disrupt organelle positioning, indicating that cytoplasmic apico-basal asymmetry is independent of the PAR polarity pathway. Blocking the apical migration of nuclei leads to the apical positioning of gut granules and yolk platelets, whereas the asymmetric localization of conventional endosomes and lipid droplets is unaltered. This suggests that nuclear positioning organizes some, but not all, cytoplasmic asymmetries in this cell type. We show that gut granules become apically enriched when WHT-2 and WHT-7 function is disrupted, identifying a novel role for ABCG transporters in gut granule positioning during epithelial polarization. Analysis of WHT-2 and WHT-7 ATPase mutants is consistent with a WHT-2/WHT-7 heterodimer acting as a transporter in gut granule positioning. In wht-2(-) mutants, the polarized distribution of other organelles is not altered and gut granules do not take on characteristics of conventional endosomes that could have explained their apical mispositioning. During epithelial polarization wht-2(-) gut granules exhibit a loss of the Rab32/38 family member GLO-1 and ectopic expression of GLO-1 is sufficient to rescue the basal positioning of wht-2(-) and wht-7(-) gut granules. Furthermore, depletion of GLO-1 causes the mislocalization of the endolysosomal RAB-7 to gut granules and RAB-7 drives the apical mispositioning of gut granules when GLO-1, WHT-2, or WHT-7 function is disrupted. We suggest that ABC transporters residing on gut granules can regulate Rab dynamics to control organelle positioning during epithelial polarization.

Radiologic Differentiation of Primary CNS Posttransplant Lymphoproliferative Disorder From Brain Metastasis.

OBJECTIVE. Primary CNS posttransplant lymphoproliferative disorder (PTLD) may present as multiple contrast-enhancing intraaxial lesions, often with central necrosis and surrounding edema. This imaging appearance is similar to the pattern seen in brain metastases. The purpose of this study was to find differences in the radiologic features of primary CNS PTLD lesions and brain metastases. MATERIALS AND METHODS. We retrospectively reviewed the radiologic findings of 51 primary CNS PTLD lesions in 10 patients and 156 metastatic brain lesions in 25 patients. Lesion size, multifocality, location, necrosis, hemorrhage, perilesional vasogenic edema, contrast enhancement, and diffusion and perfusion features were evaluated. We used the chi-square test or Fisher exact test when appropriate to compare the findings between primary CNS PTLD lesions and brain metastases. RESULTS. Primary CNS PTLD lesions occur in the deep gray matter and periventricular locations more frequently than brain metastases (p < 0.0001) and are not present at the gray and white matter junctions and vascular border zones as commonly as brain metastases are (p < 0.0001). Primary CNS PTLD tends to have less frequent hemorrhage (p < 0.0001), more restricted diffusion (p = 0.001), and lower perfusion (p = 0.002) than brain metastases. We did not find statistically significant differences between primary CNS PTLD and brain metastases for lesion size, multifocality, necrosis, and perilesional edema. CONCLUSION. The imaging characteristics of primary CNS PTLD overlap considerably with those of brain metastases, but there are significant differences between primary CNS PTLD lesions and brain metastases in lesion location, diffusion and perfusion features, and tendency to hemorrhage.

Accuracy analysis of fMRI and MEG activations determined by intraoperative mapping.

OBJECTIVE: By looking at how the accuracy of preoperative brain mapping methods vary according to differences in the distance from the activation clusters used for the analysis, the present study aimed to elucidate how preoperative functional neuroimaging may be used in such a way that maximizes the mapping accuracy. METHODS: The eloquent function of 19 patients with a brain tumor or cavernoma was mapped prior to resection with both functional MRI (fMRI) and magnetoencephalography (MEG). The mapping results were then validated using direct cortical stimulation mapping performed immediately after craniotomy and prior to resection. The subset of patients with equivalent MEG and fMRI tasks performed for motor (n = 14) and language (n = 12) were evaluated as both individual and combined predictions. Furthermore, the distance resulting in the maximum accuracy, as evaluated by the J statistic, was determined by plotting the sensitivities and specificities against a linearly increasing distance threshold. RESULTS: fMRI showed a maximum mapping accuracy at 5 mm for both motor and language mapping. MEG showed a maximum mapping accuracy at 40 mm for motor and 15 mm for language mapping. At the standard 10-mm distance used in the literature, MEG showed a greater specificity than fMRI for both motor and language mapping but a lower sensitivity for motor mapping. Combining MEG and fMRI showed a maximum accuracy at 15 mm and 5 mm-MEG and fMRI distances, respectively-for motor mapping and at a 10-mm distance for both MEG and fMRI for language mapping. For motor mapping, combining MEG and fMRI at the optimal distances resulted in a greater accuracy than the maximum accuracy of the individual predictions. CONCLUSIONS: This study demonstrates that the accuracy of language and motor mapping for both fMRI and MEG is heavily dependent on the distance threshold used in the analysis. Furthermore, combining MEG and fMRI showed the potential for increased motor mapping accuracy compared to when using the modalities separately.Clinical trial registration no.: NCT01535430 (clinicaltrials.gov).

Multimodal neuroimaging evidence of alterations in cortical structure and function in HIV-infected older adults.

Combination antiretroviral therapy transformed human immunodeficiency virus (HIV)-infection from a terminal illness to a manageable condition, but these patients remain at a significantly elevated risk of developing cognitive impairments and the mechanisms are not understood. Some previous neuroimaging studies have found hyperactivation in frontoparietal networks of HIV-infected patients, whereas others reported aberrations restricted to sensory cortices. In this study, we utilize high-resolution structural and neurophysiological imaging to determine whether alterations in brain structure, function, or both contribute to HIV-related cognitive impairments. HIV-infected adults and individually matched controls completed 3-Tesla structural magnetic resonance imaging (sMRI) and a mechanoreception task during magnetoencephalography (MEG). MEG data were examined using advanced beamforming methods, and sMRI data were analyzed using the latest voxel-based morphometry methods with DARTEL. We found significantly reduced theta responses in the postcentral gyrus and increased alpha activity in the prefrontal cortices of HIV-infected patients compared with controls. Patients also had reduced gray matter volume in the postcentral gyrus, parahippocampal gyrus, and other regions. Importantly, reduced gray matter volume in the left postcentral gyrus was spatially coincident with abnormal MEG responses in HIV-infected patients. Finally, left prefrontal and postcentral gyrus activity was correlated with neuropsychological performance and, when used in conjunction, these two MEG findings had a sensitivity and specificity of over 87.5% for HIV-associated cognitive impairment. This study is the first to demonstrate abnormally increased activity in association cortices with simultaneously decreased activity in sensory areas. These MEG findings had excellent sensitivity and specificity for HIV-associated cognitive impairment, and may hold promise as a potential disease marker.

Broadband neurophysiological abnormalities in the medial prefrontal region of the default-mode network in adults with ADHD.

Previous investigations of the default-mode network (DMN) in persons with attention-deficit/hyperactivity disorder (ADHD) have shown reduced functional connectivity between the anterior and posterior aspects. This finding was originally demonstrated in adults with ADHD, then in youth with ADHD, and has been tentatively linked to ultra low frequency oscillations within the DMN. The current study evaluates the specificity of DMN abnormalities to neuronal oscillations in the ultra low frequency range, and examines the regional specificity of these DMN aberrations in medicated and unmedicated adults with, and those without ADHD. An individually matched sample of adults with and without ADHD completed 6-minute sessions of resting-state magnetoencephalography (MEG). Participants with ADHD were known responders to stimulant medications and completed two sessions (predrug/postdrug). MEG data were coregistered to the participant's MRI, corrected for head motion, fitted to a regional-level source model, and subjected to spectral analyses to extract neuronal population activity in regions of the DMN. The unmedicated adults with ADHD exhibited broadband deficits in medial prefrontal cortices (MPFC), but not other DMN regions compared to adults without ADHD. Unmedicated patients also showed abnormal cross-frequency coupling in the gamma range between the MPFC and posterior cingulate areas, and disturbed balance within the DMN as activity in posterior regions was stronger than frontal regions at beta and lower frequencies, which dissipated at higher γ-frequencies. Administration of pharmacotherapy significantly increased prefrontal alpha activity (8-14 Hz) in adults with ADHD, and decreased the cross-frequency gamma coupling. These results indicate that neurophysiological aberrations in the DMN of patients with ADHD are not limited to ultra slow oscillations, and that they may be primarily attributable to abnormal broadband activity in the MPFC.

Atypical coupling between posterior regions of the default mode network in attention-deficit/hyperactivity disorder: a pharmaco-magnetoencephalography study.

BACKGROUND: Dysfunction in the default mode network (DMN), a group of cortical areas more active during the resting state, has been linked to attentional deficits and symptoms associated with attention-deficit/hyperactivity disorder (ADHD). Prior imaging studies have shown decreased functional connectivity between DMN nodes in patients with ADHD, primarily between anterior and posterior regions. Using magnetoencephalography (MEG), we evaluated phase coherence (i.e., functional connectivity) among regions of the DMN in healthy controls and adults with ADHD before and after stimulant therapy. METHODS: We obtained a resting-state MEG recording for all participants. Magnetoencephalography data were transformed into a ~30 node regional source model using inverse spatial filtering, including regions corresponding to the DMN. We computed the zero-lag phase coherence between these regions pairwise for 5 distinct frequency bands, and we assessed group and medication effects. RESULTS: Twelve adults with and 13 without ADHD participated in our study. Functional connectivity was stronger between particular node pairs and showed frequency-specific effects. Unmedicated patients showed reduced phase locking between posterior cingulate/precuneus regions (PCC) and right inferior parietal cortices (RIPL), and between medial prefrontal regions (MPFC) and the left inferior parietal region (LIPL) and the PCC. Unmedicated patients had increased phase locking between the RIPL and LIPL regions compared with controls. Administration of stimulants improved phase locking abnormalities along the MPFC-PCC and LIPL-RIPL pathways in patients with ADHD. LIMITATIONS: Modest sample size and lack of duration of patient treatment history may limit the generalizability of our findings. CONCLUSION: Adults with ADHD exhibit hyper- and hypoconnectivity between regions of the DMN during rest, which were suppressed after stimulant medication administration.

LIF signaling regulates outer radial glial to interneuron fate during human cortical development.

Radial glial (RG) development is essential for cerebral cortex growth and organization. In humans, the outer radial glia (oRG) subtype is expanded and gives rise to diverse neurons and glia. However, the mechanisms regulating oRG differentiation are unclear. oRG cells express leukemia-inhibitory factor (LIF) receptors during neurogenesis, and consistent with a role in stem cell self-renewal, LIF perturbation impacts oRG proliferation in cortical tissue and organoids. Surprisingly, LIF treatment also increases the production of inhibitory interneurons (INs) in cortical cultures. Comparative transcriptomic analysis identifies that the enhanced IN population resembles INs produced in the caudal ganglionic eminence. To evaluate whether INs could arise from oRGs, we isolated primary oRG cells and cultured them with LIF. We observed the production of INs from oRG cells and an increase in IN abundance following LIF treatment. Our observations suggest that LIF signaling regulates the capacity of oRG cells to generate INs.

Cervical spinal cord multiple sclerosis: evaluation with 2D multi-echo recombined gradient echo MR imaging.

OBJECTIVE: The two-dimensional multi-echo recombined gradient echo (MERGE) technique automatically acquires and sums multiple gradient echoes at various echo times in cervical spine magnetic resonance (MR) imaging. This technique increases the grey-white matter contrast within the spinal cord and should also improve the depiction of cervical cord lesions. The aim of this study was to qualitatively and quantitatively evaluate MERGE imaging compared with T2-weighted fast spin-echo (T2WFSE) imaging for depicting multiple sclerosis (MS) lesions in the cervical cord. METHODS: Nineteen consecutive patients (10 males and 9 females; age range 22-62 years, mean age 43.6 years) with clinically diagnosed MS were examined with cervical spinal cord MR imaging at 3 T including both MERGE and T2WFSE imaging. Qualitative evaluation for MS lesion conspicuity was performed. The quantitative criterion utilized to compare MERGE imaging with T2WFSE imaging was the lesion-to-background contrast-to-noise ratio (CNR). RESULTS: MERGE imaging showed 79 lesions and missed 1 that was depicted on T2WFSE imaging. T2WFSE imaging showed 46 lesions and missed 34 that were depicted on MERGE imaging. MERGE imaging was markedly superior to T2WFSE imaging in rendering greater lesion conspicuity. In the quantitative evaluation, the lesion-to-background CNR upon MERGE imaging was significantly higher than that upon T2WFSE imaging (P < 0.001, paired t-test). CONCLUSIONS: MERGE imaging in the cervical spinal cord increases detection and conspicuity of MS lesions. Strong consideration should be given to utilizing axial MERGE images in the diagnosis and follow-up study of cervical cord MS.

Evaluating survival in subjects with astrocytic brain tumors by dynamic susceptibility-weighted perfusion MR imaging.

PURPOSE: Studies have evaluated the application of perfusion MR for predicting survival in patients with astrocytic brain tumors, but few of them statistically adjust their results to reflect the impact of the variability of treatment administered in the patients. Our aim was to analyze the association between the perfusion values and overall survival time, with adjustment for various clinical factors, including initial treatments and follow-up treatments. MATERIALS AND METHODS: This study consisted of 51 patients with astrocytic brain tumors who underwent perfusion-weighted MRI with MultiHance® at a dose of 0.1 mmol/kg prior to initial surgery. We measured the mean rCBV, the 5% & 10% maximum rCBV, and the variation of rCBV in the tumors. Comparisons were made between patients with and without 2-year survival using two-sample t-test or Wilcoxon rank-sum test for the continuous data, or chi-square and Fisher exact tests for categorical data. The multivariate cox-proportional hazard regression was fit to evaluate the association between rCBV and overall survival time, with adjustment for clinical factors. RESULTS: Patients who survived less than 2 years after diagnosis had a higher mean and maximum rCBV and a larger variation of rCBV. After adjusting for clinical factors including therapeutic measures, we found no significant association of overall survival time within 2 years with any of these rCBV values. CONCLUSIONS: Although patients who survived less than 2 years had a higher mean and maximum rCBV and a larger variation of rCBV, rCBV itself may not be used independently for predicting 2-year survival of patients with astrocytic brain tumors.

Incidental Findings on Brain MRI in People with HIV Infection.

BACKGROUND: Incidental findings are a well-known complication of imaging studies done for both diagnostic and research purposes. Little is known about the rates and types of incidental findings found on brain MRI in patients with HIV infection, who may be at risk for HIV-Associated Neurocognitive Disorders (HAND). METHODS: The parent study included 108 adults with HIV infection and 125 demographically-matched uninfected controls who completed MRI and neuropsychological testing. Incidental findings were classified by the study team as vascular, neoplastic, congenital, other neurologic, or non-neurologic. Categorical measures were compared using Pearson chi-square tests; continuous measures were compared using t-tests. RESULTS: Among participants with HIV infection, 36/108 (33%) had incidental findings compared to 33/125 (26%) controls (p = 0.248). Rates of incidental findings were significantly correlated with increasing age in both participants with HIV infection (p = 0.013) and controls (p = 0.022). We found no correlation between presence of incidental findings and sex or race/ethnicity among either cohort, and no correlation with CD4 count or HAND status for the HIV-infected cohort. CONCLUSIONS: Incidental findings were common in both participants with HIV infection and controls, at higher rates than previously reported in healthy populations. There was no significant difference in prevalence between the groups.

Primary central nervous system post-transplant lymphoproliferative disorders: the spectrum of imaging appearances and differential.

OBJECTIVE: Central nervous system post-transplant lymphoproliferative disorder (CNS-PTLD) is a rare disease that presents with non-specific signs and symptoms. The purpose of this article is to present the imaging appearances of CNS-PTLD by magnetic resonance imaging. We highlight the differential diagnostic considerations including primary central nervous system lymphoma, glioblastoma, cerebral abscess, and metastatic disease. This is an important topic to review since in daily practice the diagnosis of CNS-PTLD is often not initially considered when present due to its rarity and the lack of radiologists' familiarity with the disease. CONCLUSION: Knowing the unique imaging features of CNS-PTLD narrows the differential diagnosis, facilitates the diagnostic work-up, and optimizes making the diagnosis. Advanced MRI data for CNS PTLD is limited but is promising for helping with narrowing the differential diagnosis.

Post-operative perfusion and diffusion MR imaging and tumor progression in high-grade gliomas.

PURPOSE: Perfusion and diffusion magnetic resonance imaging (MRI) provide important biomarkers for brain tumor analysis. Our aim was to investigate if regions of increased perfusion or tumor with restricted diffusion on the immediate post-operative MRI examination would be predictive of time to tumor progression in patients with high-grade gliomas. MATERIALS AND METHODS: Twenty-three patients with high-grade gliomas were retrospectively analyzed. We measured the perfusion at the resection area and evaluated the presence or absence of the restricted diffusion in residual tumor masses. The associations of the perfusion, diffusion and contrast enhancement (delayed static enhancement (DSE)) characteristics with time to tumor progression were statistically calculated. We also evaluated if the location of the tumor progression was concordant to the areas of the elevated perfusion, tumor type restricted diffusion and enhancement. RESULTS: Patients with >200 days to progression are more likely to have no elevated relative cerebral blood volume (rCBV) ratio (p = 0.0004), no tumor restriction (p = 0.024), and no DSE (p = 0.052). The elevated mean rCBV ratio (p<0.001) and tumor type restricted diffusion (p = 0.002) were significantly associated with a higher risk of progression. All cases with rCBV ratio of >1.5 progressed in 275 days or earlier. Tumors tended to progress at the area where patients with post-operative MRIs showed elevated perfusion (p = 0.006), tumor-type restricted diffusion (p = 0.005) and DSE (p = 0.008). CONCLUSIONS: Post-operative analysis of rCBV, tumor type restricted diffusion and enhancement characteristics are predictive of time to progression, risk of progression and where tumor progression is likely to occur.

Multiple endocrine neoplasia.

MEN1 and MEN2 are autosomal dominant cancer syndromes with the potential for considerable morbidity and mortality. Better understanding of the molecular pathogenesis in MEN1 and MEN2 has fostered the development of specific DNA screening. Knowing the genetic status of patients is valuable for making decisions regarding surveillance and interventions, such as prophylactic thyroidectomy for medullary thyroid cancer. Identifying new RET pathways has provided molecular targets for therapies that currently are being tested in clinical trials for locally advanced, metastatic, and recurrent medullary thyroid cancer.

MR imaging with diffusion-weighted imaging in acute and chronic Wernicke encephalopathy.

Wernicke encephalopathy is a neurologic disorder that results from thiamine deficiency. It is associated with a classic triad of symptoms consisting of ataxia, ocular motor cranial neuropathies, and changes in consciousness. We report 3 cases of Wernicke encephalopathy in which MR imaging, including diffusion-weighted imaging, was performed at the onset and during follow-up. MR imaging findings were correlated with the clinical status of both the acute and chronic stage of Wernicke encephalopathy.

Can tumor contrast enhancement be used as a criterion for differentiating tumor grades of oligodendrogliomas?

BACKGROUND AND PURPOSE: The association of high-grade oligodendrogliomas with tumor contrast material enhancement on MR images has been reported. Some authors have even used contrast enhancement as a criterion for their oligodendroglioma grading system. The purpose of our study was to evaluate if tumor contrast enhancement is a specific finding for anaplastic oligodendroglioma. METHODS: Pretreatment MR images of 24 oligodendrogliomas were reviewed retrospectively, and findings were compared with the histologic grade. The presence or absence and the pattern of tumor contrast enhancement were evaluated qualitatively. A contrast enhancement ratio (CER), a quantitative criterion, was calculated to assess the difference in degree of enhancement between the low-grade and anaplastic tumors. Tumor grade was diagnosed at pathologic examination according to the World Health Organization classification system. RESULTS: Contrast enhancement was noted in nine (56%) of 16 low-grade tumors and in five (62%) of eight anaplastic tumors. A characteristic enhancement pattern, nodular-like enhancement, was found in eight tumors. The CERs were 2.12-40.88 (mean, 20.08) in low-grade tumors and were 3.20-62.52 (mean, 28.73) in anaplastic tumors (P > .05). CONCLUSION: Tumor contrast enhancement was not statistically significantly different between the tumor groups. We believe that the presence or absence of tumor contrast enhancement is not a specific finding for simply discriminating low-grade from anaplastic oligodendrogliomas. Histologic confirmation is necessary even in tumors without contrast enhancement.

Fluid-attenuated inversion-recovery MR imaging in assessment of intracranial oligodendrogliomas.

This retrospective study consisted of 17 consecutive patients with oligodendrogliomas. We qualitatively and quantitatively assessed the diagnostic value of fluid-attenuated inversion-recovery (FLAIR) images compared with T2-weighted fast spin-echo (FSE) images for evaluating intracranial oligodendrogliomas. Qualitative evaluations of signal intensity, tumor conspicuity, definition of tumor margin, distinction between solid and cystic-like parts within tumor, and calcification were performed. Quantitative criteria comparing FLAIR to T2-weighted FSE images included tumor-to-background contrast and contrast-to-noise ratio (CNR) and tumor-to-cerebrospinal fluid (CSF) contrast and CNR. Our results demonstrate that the FLAIR sequence can replace the T2-weighted FSE sequence for evaluating oligodendrogliomas.

Evolution of lesions in Susac syndrome at serial MR imaging with diffusion-weighted imaging and apparent diffusion coefficient values.

BACKGROUND AND PURPOSE: Susac syndrome is a rare disorder consisting of encephalopathy, hearing loss, and retinal arteriolar occlusions. The purpose of this study was to evaluate the evolution of lesions in this disease by using serial MR imaging with diffusion-weighted imaging (DWI) and apparent diffusion coefficients (ADCs). Abnormalities in the nonlesional white matter (NLWM) were also analyzed. METHODS: Serial MR and DWI findings in two patients with Susac syndrome were reviewed retrospectively. ADCs of the lesions and the NLWM were compared with values of the corresponding anatomical regions in 16 control subjects. RESULTS: T2-weighted images, DWIs, and fluid-attenuated inversion-recovery (FLAIR) images demonstrated diffuse small hyperintense lesions predominantly involving the corpus callosum, white matter, cerebral cortex, and deep gray structures. During the whole course in the two patients, 437, 295, and 113 lesions were depicted on FLAIR images, T2-weighted images, and DWIs, respectively. With the aggravation and mitigation of the clinical symptoms, the size and number of the lesions changed over time. Of 65 lesions with measured ADCs, six had restricted ADCs (5.29-6.91 x 10(-4) mm(2)/s), and 29 had elevated ADCs (8.02-13.5 x 10(-4) mm(2)/s). With disease progression, ADCs in the NLWM changed from normal to elevated; this corresponded to the diffuse signal-intensity change seen in the white matter. CONCLUSION: FLAIR imaging is the most sensitive sequence for detecting lesions of Susac syndrome. DWI is useful in demonstrating the heterogeneous nature of lesions, depicting occult abnormalities in the white matter, elucidating underlying pathologic processes, and conducting patient follow-up.

Neurovascular injuries of the spinal cord.

Neurovascular spinal cord injuries are very prevalent and in a busy trauma center radiology practice these injuries are commonly seen. Imaging neurovascular injuries has been greatly facilitated by magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA). The histopathological changes that occur with spinal cord trauma have been found to correlate well with what is seen on MRI examinations. The MRI findings in spinal cord trauma have also been found to be useful in determining patient prognosis. Spinal cord infarcts due to arterial injury from trauma are relatively rare, but it has been shown by imaging that vertebral artery injuries are not an unusual occurrence. The specific findings associated with neurovascular injuries will be described with an emphasis on the findings on MRI and MRA examinations. MRI and MRA techniques have become the procedure of choice for evaluating neurovascular injuries because of their proven accuracy and because they are non-invasive. Conventional angiography, although, does remain quite useful for evaluating arterial injuries.