Magnetic resonance imaging and Ménière's disease-unavoidable alliance.

Ménière's disease (MD) is a clinical syndrome characterized by recurrent episodes of spontaneous vertigo, unilateral fluctuating sensorineural hearing loss, tinnitus, and aural fullness. Endolymphatic hydrops is recognized as the pathophysiological substrate of the disease, having been demonstrated in anatomical pathological studies and more recently by magnetic resonance imaging (MRI). The current criteria of the disease, however, remain symptom based and do not include the demonstration of endolymphatic hydrops. The authors review MRI techniques and diagnostic criteria of endolymphatic hydrops and the role of MRI in MD is discussed.

A distinct neuromelanin magnetic resonance imaging pattern in parkinsonian multiple system atrophy.

BACKGROUND: Parkinsonian variant of multiple system atrophy is a neurodegenerative disorder frequently misdiagnosed as Parkinson's disease. No early imaging biomarkers currently differentiate these disorders. METHODS: Simple visual imaging analysis of the substantia nigra and locus coeruleus in neuromelanin-sensitive magnetic resonance imaging and nigrosome 1 in susceptibility-weighted sequences was performed in thirty patients with parkinsonian variant of multiple system atrophy fulfilling possible/probable second consensus diagnostic criteria. The neuromelanin visual pattern was compared to patients with Parkinson's disease with the same disease duration (n = 10) and healthy controls (n = 10). Substantia nigra semi-automated neuromelanin area/signal intensity was compared to the visual data. RESULTS: Groups were similar in age, sex, disease duration, and levodopa equivalent dose. Hoehn & Yahr stage was higher in parkinsonian multiple system atrophy patients, 69% of whom had normal neuromelanin size/signal, significantly different from Parkinson's disease patients, and similar to controls. Nigrosome 1 signal was lost in 74% of parkinsonian multiple system atrophy patients. Semi-automated neuromelanin substantia nigra signal, but not area, measurements were able to differentiate groups. CONCLUSIONS: In patients with parkinsonism, simple visual magnetic resonance imaging analysis showing normal neuromelanin substantia nigra and locus coeruleus, combined with nigrosome 1 loss, allowed the distinction of the parkinsonian variant of multiple system atrophy from Parkinson's disease and healthy controls. This easy and widely available method was superior to semi-automated measurements in identifying specific imaging changes in substantia nigra and locus coeruleus.

Metronidazole-induced encephalopathy in a patient with spondylodiscitis.

INTRODUCTION: Metronidazole-induced encephalopathy is an uncommon but potentially severe complication of metronidazole treatment. Although the exact pathophysiology remains elusive, proposed hypotheses include RNA binding, neurotoxicity from free radicals, and modulation of neurotransmitter receptors. Most cases demonstrate improvement upon discontinuation of metronidazole, highlighting the importance of early recognition. Magnetic resonance imaging plays a critical role in diagnosing metronidazole-induced encephalopathy, with characteristic imaging findings frequently observed in the dentate nuclei and corpus callosum. CASE SUMMARY: A 63-year-old man treated with metronidazole for lumbar spondylodiscitis developed neurological symptoms consistent with metronidazole-induced encephalopathy. IMAGES: Magnetic resonance imaging revealed characteristic bilateral hyperintense lesions in the cerebellar dentate nuclei, corpus callosum, and brainstem. Prompt recognition and discontinuation of metronidazole led to symptom resolution. CONCLUSION: This case underscores the importance of clinicians and radiologists being aware of this condition and emphasizes the pivotal role of magnetic resonance imagining in establishing the diagnosis.

A ventral brainstem neurenteric cyst - A case report and review of the pre-brainstem location.

Background: Neurenteric cysts are uncommon, benign endoderm-derived lesions that result from aberrant embryologic development of the notochord. They are typically located in the intradural extramedullary spinal cord and rarely located intracranially. Contrary to spinal-located cysts, intracranial cysts are rarer in the pediatric population. Clinically, they may present with symptoms of mass effect, or they can be incidentally discovered. Case Description: A 10-year-old healthy female child presented with recurrent headaches. The physical and neurological examination was unremarkable. Brain magnetic resonance imaging (MRI) showed a well-demarcated lesion anterior to the pontomedullary junction with striking T1 and T2/T2 fluid-attenuated inversion recovery high-signal intensity and a small rounded nodule within of low signal on T1, T2, and T2*. On initial conservative strategy with serial brain MRI, there was a progressive enlargement of the lesion with significant mass effect on the brainstem. The patient underwent a right retrosigmoid craniotomy, and the cyst wall was fenestrated and drained. Part of the cyst wall and the solid nodule were adherent to the brainstem and basilar artery and were not removed. The histologic findings were consistent with the diagnosis of a benign endodermal cyst. The postoperative period was uneventful. Conclusion: We report a successful surgical treatment of this rare congenital cyst located in the ventral brainstem. We present pre-and post-operative imaging findings, intraoperative microscopic images of the procedure, and a brief review of relevant clinical literature on the topic.

Determining the Profile of People with Fall Risk in Community-Living Older People in Algarve Region: A Cross-Sectional, Population-Based Study.

One in three people aged 65 years or older falls every year. Injuries associated with this event among the older population are a major cause of pain, disability, loss of functional autonomy and institutionalization. This study aimed to assess mobility and fall risk (FR) in community-living older people and to determine reliable and independent measures (health, social, environmental and risk factors) that can predict the mobility loss and FR. In total, 192 participants were included, with a mean age of 77.93 ± 8.38. FR was assessed by EASY-Care (EC) Standard 2010, the Tinetti Test and the Modified Falls Efficacy Scale (MFES). An exploratory analysis was conducted using the divisive non-hierarchical cluster method, aiming to identify a differentiator and homogeneous group of subjects (optimal group of variables) and to verify if that group shows differences in fall risk. Individually, the health, social, environmental and risk factor categories were not found to be an optimal group; they do not predict FR. The most significant predictor variables were a mix of the different categories, namely, the presence of pain, osteoarthritis (OA), and female gender. The finding of a profile that allows health professionals to be able to quickly identify people at FR will enable a reduction in injuries and fractures resulting from falls and, consequently, the associated costs.

Neuroimaging cerebrovascular biomarkers in Parkinson's disease.

BACKGROUND AND PURPOSE: The cardiovascular risk in Parkinson's disease (PD) remains uncertain and controversial. Some studies suggest PD patients present an increased risk of cerebrovascular disease. We aimed to study the prevalence of neuroimaging cerebrovascular biomarkers in PD patients compared to controls, using an accurate and complete magnetic resonance (MR) imaging evaluation. MATERIAL AND METHODS: Neuroimaging sub-study within a larger cross-sectional case-control study. An enriched subgroup of PD patients (≤10 years since diagnosis) with at least a moderate cardiovascular mortality risk based on a Systematic COronary Risk Evaluation (SCORE) was compared to community-based controls regarding neuroimaging biomarkers. Patients underwent a high-resolution T1-weighted MR imaging sequence at 3.0 T to visualize neuromelanin. A 3D SWI FFE, sagittal 3D T1-weighted, axial FLAIR and diffusion-weighted image sequences were obtained. RESULTS: The study included 47 patients, 24 with PD and 23 controls. PD patients presented a reduced area and signal intensity of the substantia nigra and locus coeruleus on neuromelanin-sensitive MR. The median SCORE was 5% in both groups. No significant differences regarding white matter hyperintensities (OR 4.84, 95% CI 0.50, 47.06), lacunes (OR 0.43, 95% CI 0.07, 2.63), microbleeds (OR 0.64, 95% CI 0.13, 3.26), or infarcts (0.95, 95% CI 0.12, 7.41) was found. The frequency of these neuroimaging biomarkers was very low in both groups. CONCLUSION: The present study does not support an increased prevalence of neuroimaging cerebrovascular biomarkers in PD patients.

MR Imaging of Cochlear Modiolus and Endolymphatic Hydrops in Patients With Menière's Disease.

Background: Menière's disease (MD) is an inner ear disorder characterized by recurrent episodes of spontaneous vertigo, unilateral low-frequency sensorineural hearing loss, tinnitus, and aural fullness. Current diagnosis still often has to rely on subjective and audiometric criteria only, although endolymphatic hydrops is recognized as the pathophysiological substrate of the disease, having been demonstrated in anatomical pathological studies and by magnetic resonance (MRI). The modiolus has a close functional and anatomical relationship with the cochlear nerve and membranous labyrinth and can be evaluated with MRI but no data exist on the modiolar size in MD. Purpose: Our purpose is to examine the following hypothesis. Is cochlear modiolus smaller in symptomatic ears in MD? Methods: We used a retrospective 3 Tesla MR study (heavily T2-weighted 3D fast asymmetric spin-echo images and 0.5 mm slice thickness) comparing the mean modiolar area (MMA) in the index and best ears of eight patients with definite MD based on audiometric data. The obtained MMA values were compared against the audiometric data and the presence of vestibular endolymphatic hydrops. Results: No differences were seen in MMA between best and worst ears. Ears with a pure tone average (PTA) ≥25 dB and more pronounced endolymphatic hydrops showed lower MMA (not statistically significant). Two patients with extreme endolymphatic hydrops showed a noteworthy ipsilateral decrease in the cochlear modiolus area. Conclusion: No differences were seen in MMA between best and worst ears in definite MD. Worse hearing function (PTA ≥ 25dB) and more pronounced endolymphatic hydrops seem to be associated with lower MMA. This might be related to bone remodeling as a consequence of endolymphatic hydrops. Further research is needed to corroborate and explore these findings.

Congenital Absence of the Internal Carotid Artery With Intercavernous Anastomosis.

Absence of the internal carotid artery (ICA) is a rare congenital anomaly. Six pathways of alternative collateral circulation have been described. We present a case depicting absence of the left ICA and a Lie type D pattern of collateral circulation, with an intercavernous branch from the right cavernous ICA passing along the floor of the sella to the contralateral side, supplying the left middle cerebral artery. Association with cerebral aneurysms has been found, as seen in this case. Recognition of this vascular anatomic variant is important to understand thromboembolic disease in these patients and the increased risks of surgery, such as transsphenoidal pituitary surgery. Also, it highlights the importance of imaging these patients to detect and monitor associated cerebral aneurysms.

Neuromelanin Magnetic Resonance Imaging of the Substantia Nigra in Huntington's Disease.

BACKGROUND: Huntington's disease (HD) is an autosomal-dominant neurodegenerative disorder inducing motor, psychiatric changes and cognitive decline, characterized pathologically by striatal atrophy. Pathological changes in the extra-striatal structures, such as the substantia nigra (SN), and abnormalities in pre-synaptic striatal dopamine neurotransmission are also known to occur. Neuromelanin (NM)-sensitive magnetic resonance imaging (NM-MRI) is an innovative technique that was recently developed allowing the in vivo study of pathological changes in the dopaminergic neurons of the SN. OBJECTIVE: To investigate the SN MR signal in HD patients. METHODS: We performed a cross-sectional study using a specific T1-weighted MR sequence to visualize NM. The areas and signal intensity contrast ratios of the T1 hyperintense SN regions were obtained using a semi-automatic segmentation method. RESULTS: A total of 8 HD patients and 12 healthy subjects were evaluated. The SN area was markedly reduced in the HD group compared with the control group (p = 0.02), even after normalization of the SN area with the midbrain area and age correction (p = 0.01). There was a significant reduction in the intensity contrast ratio of the hyperintense SN areas to crus cerebri in HD patients comparing with controls (p = 0.04) after correction for age. CONCLUSIONS: NM-sensitive MR techniques were used for the first time to study the SN in HD patients, showing loss of NM in this region, supporting the implication of dopaminergic neuronal changes in disease pathology. Future research needs to be conducted to evaluate the potential of SN area and intensity contrast as biomarkers for HD.

Extracellular Matrix Modulation Is Driven by Experience-Dependent Plasticity During Stroke Recovery.

Following stroke, complete cellular death in the ischemic brain area may ensue, with remaining brain areas undergoing tissue remodelling to various degrees. Experience-dependent brain plasticity exerted through an enriched environment (EE) promotes remodelling after central nervous system injury, such as stroke. Post-stroke tissue reorganization is modulated by growth inhibitory molecules differentially expressed within the ischemic hemisphere, like chondroitin sulfate proteoglycans found in perineuronal nets (PNNs). PNNs in the neocortex predominantly enwrap parvalbumin-containing GABAergic (PV/GABA) neurons, important in sensori-information processing. Here, we investigate how extracellular matrix (ECM) proteases and their inhibitors may participate in the regulation of PNN integrity during stroke recovery. Rats were subjected to photothrombotic stroke in the motor cortex, and functional deficits were assessed at 7 days of recovery. Sham and stroked rats were housed in either standard or EE conditions for 5 days, and infarct volumes were calculated. PNNs were visualized by immunohistochemistry and counted in the somatosensory cortex of both hemispheres. mRNA expression levels of ECM proteases and protease inhibitors were assessed by RT-qPCR and their activity analyzed by gel zymography. PNNs and protease activity were also studied in brains from stroke patients where similar results were observed. EE starting 2 days after stroke and continuing for 5 days stimulated behavioral recovery of limb-placement ability without affecting infarct size. EE promoted a decrease of PNNs around PV/GABA neurons and a concomitant modulation of the proteolytic activity and mRNA expression of ECM proteases and protease inhibitors in the somatosensory cortex. This study provides molecular targets for novel therapies that could support rehabilitation of stroke patients.