Sofia Reimão

Substantia nigra neuromelanin magnetic resonance imaging in de novo Parkinson's disease patients

Depigmentation of the substantia nigra (SN) and locus coeruleus (LC) is a conspicuous pathological feature of Parkinsons disease (PD) and is related to the loss of neuromelanin, whose paramagnetic properties result in high signal on specific T1‐weighted magnetic resonance imaging (MRI). Recent studies have suggested that neuromelanin decrease in the SN and LC of PD patients may emerge as a possible diagnostic biomarker. The SN neuromelanin signal in de novo and early stage PD patients was studied to assess its diagnostic accuracy. This is the first study based on a semi‐automated MRI analysis of the neuromelanin signal in de novo PD patients.

Substantia nigra neuromelanin-MR imaging differentiates essential tremor from Parkinson's disease.

Essential tremor (ET) is a very common movement disorder that has no diagnostic markers. Differentiation with Parkinsons disease (PD) can be clinically challenging in some cases, with a high rate of misdiagnosis. Magnetic resonance imaging (MRI) studies have been able to identify neuromelanin changes in the substantia nigra (SN) of PD patients, but they have thus far not been investigated in ET. In this study, we aimed to characterize neuromelanin‐MR signal changes in ET and evaluate its diagnostic accuracy in the differential diagnosis with PD.

Magnetic resonance correlation of iron content with neuromelanin in the substantia nigra of early‐stage Parkinson's disease

Magnetic resonance (MR) studies have demonstrated a significant reduction of neuromelanin in the substantia nigra (SN) of Parkinsons disease (PD) patients with high accuracy for differential diagnosis compared to non‐PD controls and essential tremor. However, studies state that not knowing how paramagnetic effects of iron influence neuromelanin signal is a limitation. In this study a neuromelanin‐sensitive MR sequence was combined with T2* relaxometry iron quantification analysis to study the SN of early‐stage PD patients to investigate the correlation between these parameters.

Neurosyphilis versus Herpes Encephalitis in a Patient with Confusion, Memory Loss, and T2-Weighted Mesiotemporal Hyperintensity.

Acute confusion and memory loss associated with asymmetrical mesiotemporal hyperintensity on T2-weighted MRI are characteristic of herpes encephalitis. The authors report the case of a patient with these symptoms and MRI presentation who had neurosyphilis. Recently clinical and imaging patterns usually associated with herpes simplex encephalitis have been seen in patients with neurosyphilis. Because syphilis is “The Great Pretender” not only clinically but also in imaging and because its numbers are rising, it must be sought as a differential diagnosis.

Advanced MR Imaging of the Human Nucleus Accumbens--Additional Guiding Tool for Deep Brain Stimulation.

The human nucleus accumbens (Acc) has become a target for deep brain stimulation (DBS) in some neuropsychiatric disorders. Nonetheless, even with the most recent advances in neuroimaging it remains difficult to accurately delineate the Acc and closely related subcortical structures, by conventional MRI sequences. It is our purpose to perform a MRI study of the human Acc and to determine whether there are reliable anatomical landmarks that enable the precise location and identification of the nucleus and its core/shell division.

Orofacial apraxia in motor neuron disease.

Introduction: Cognitive and behavioral impairments are considered to occur frequently in amyotrophic lateral sclerosis/motor neuron disease (MND). Rarely, apraxia has been reported in MND. Orofacial, or buccofacial, apraxia is characterized by a loss of voluntary control of facial, lingual, pharyngeal and masticatory muscles in the presence of preserved reflexive and automatic functions of the same muscles. Methods: We report a patient with MND who presented with spastic dysarthria and asymmetric orofacial apraxia. She progressed to frontotemporal dementia (FTD). Results: Clinical and neurophysiological examinations were suggestive of bulbar-onset MND-FTD. Tractography showed a reduction of fractional anisotropy in the centrum semiovale, corona radiata, corticomedullary pathway and inferior aspect of the medulla; the changes were more severe on the left side. To our knowledge, this is the first report of an asymmetric presentation of an apraxic syndrome in MND-FTD.

Neck hematoma after intravenous thrombolysis for stroke treatment.

or sign of trauma. Neurological examination disclosed hemi-inattention, left gaze palsy, left homonymous hemianopia, dysarthria, left facial paresis, hemisensory loss and hemiparesis (NIHSS score 14). A brain computerized tomography (CT) scan was unremarkable. Platelet count, activated partial thromboplastin time and prothrombin time were normal. Intravenous rtPA administration was started 2.5 h after symptom onset with a total alteplase dose of 68 mg (0.9 mg/kg). Fifty minutes after perfusion start, hemi-inattention and limb weakness increased (NIHSS score 17). At the end of rtPA perfusion, a right cervical hematoma was noticed ( fig. 1 a). Cervical CT performed 1 h afterwards showed a hematoma surrounding the right internal carotid artery (ICA) extending to the subcutaneous neck tissue and a diminished caliber of the right ICA lumen ( fig. 1 b, c). There was no further deterioration of the neurological status or vital parameters, although an increase in the superficial neck hematoma was noticed. No specific treatment for the cervical hematoma was provided. The next day, brain CT confirmed a large infarction in the territory of the right middle cerebral artery. Cervical ultrasonography and digital brain angiography showed a non-atherosclerotic occlusion of the right ICA. Magnetic resonance imaging of the neck with fat-suppressed T 1 -weighted sequences performed 2 weeks after stroke onset disclosed a hematoma surrounding the initial segment of the right ICA. Coagulation, autoimmunity and serological studies were unremarkable. A transesophageal echocardiogram revealed a ‘patent foramen ovale’. The patient was discharged receiving aspirin 250 mg/day. Introduction Bleeding is a feared adverse effect of intravenous thrombolysis. Despite the widespread use of intravenous recombinant tissuetype plasminogen activator (rtPA) in stroke, there are few significant extracranial bleedings [1–3] . We report a case of neck hematoma after intravenous rtPA for stroke, which to our best knowledge has not been previously described.

Substantia Nigra Neuromelanin as an Imaging Biomarker of Disease Progression in Parkinson’s Disease

BACKGROUND A specific T1-weighted magnetic resonance imaging (MRI) sequence has been shown to detect substantia nigra (SN) neuromelanin (NM) signal changes that accurately discriminate Parkinsons disease (PD) patients from controls, even in early disease stages. However, it is unclear what happens to these SN changes in later disease stages and if they can be a marker of disease progression. OBJECTIVE to investigate the pattern of SN-NM area loss and contrast ratio (CR) intensity changes in late-stage PD (LSPD) compared to earlier disease stages. METHODS A comparative cross-sectional study was performed, analyzing SN-NM MRI signal in LSPD (Schwab and England Activities of Daily Living Scale score <50 or Hoehn Yahr Stage [HY] >3), comparing this group with de novo, 2-5 year PD and controls. SN-NM signal area and CR values for the internal and lateral SN regions were obtained with semi-automated methods. RESULTS 13 LSPD, 12 de novo patients with PD, 10 PD patients with a 2-5 year disease duration, and 10 controls were included. NM signal area was significantly decreased in LSPD compared to de novo PD (P-value = 0.005; sensitivity: 75%; specificity 92% and AUC: 0.86). In the lateral SN region, a decrease in the CR was detected in all PD groups compared to controls; despite not reaching statistical significance, a slight increment was observed comparing LSPD to 2-5 year PD. NM signal area significantly correlated with HY (R = -0.37; P < 0.05) and Movement disorder Society Unified Parkinsons Disease Rating Scale part II (MDS-UPDRS) (R = -0.4; P < 0.05) while a weak correlation was found with MDS-UPDRS part III (R = -0.26; P: 0.1). CONCLUSION SN area evaluated by NM-sensitive MRI may be a promising biomarker of nigral degeneration and disease progression in PD patients.

Diffusion Tensor Imaging in Movement Disorders: Review of Major Patterns and Correlation with Normal Brainstem/cerebellar White Matter

The authors reviewed the diffusion tensor imaging (DTI) and tractography (DTT) of the normal brainstem and cerebellar white matter in normal volunteers, correlating it with structural magnetic resonance (MR) imaging and DTI data obtained in patients evaluated in our institution with movement disorders, including multisystem atrophy (MSA), spinocerebellar ataxia (SCA), progressive supra-nuclear palsy (PSP) and idiopathic Parkinsons disease (PD). DTI and tractography data demonstrated major white-matter fibers within the brain stem and cerebellum, including cortico-spinal tracts, transverse pontine fibers, medial lemniscus and cerebellar peduncles. Visualization of selective degeneration of these individual fibre tracts with DTI, in our cases, added qualitative data to the differential diagnosis of movement disorders.

Beyond fractional anisotropy in amyotrophic lateral sclerosis: the value of mean, axial, and radial diffusivity and its correlation with electrophysiological conductivity changes

PurposeThis paper aims to analyze the contribution of mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) in the detection of microstructural abnormalities in amyotrophic lateral sclerosis (ALS) and to evaluate the degree of agreement between structural and functional changes through concomitant diffusion tensor imaging (DTI), transcranial magnetic stimulation (TMS), and clinical assessment.MethodsFourteen patients with ALS and 11 healthy, age- and gender-matched controls were included. All participants underwent magnetic resonance imaging including DTI. TMS was additionally performed in ALS patients. Differences in the distribution of DTI-derived measures were assessed using tract-based spatial statistical (TBSS) and volume of interest (VOI) analyses. Correlations between clinical, imaging, and neurophysiological findings were also assessed through TBSS.ResultsALS patients showed a significant increase in AD and MD involving the corticospinal tract (CST) and the pre-frontal white matter in the right posterior limb of the internal capsule (p < 0.05) when compared to the control group using TBSS, confirmed by VOI analyses. VOI analyses also showed increased AD in the corpus callosum (p < 0.05) in ALS patients. Fractional anisotropy (FA) in the right CST correlated significantly with upper motor neuron (UMN) score (r = − 0.79, p < 0.05), and right abductor digiti minimi central motor conduction time was highly correlated with RD in the left posterior internal capsule (r = − 0.81, p < 0.05). No other significant correlation was found.ConclusionMD, AD, and RD, besides FA, are able to further detect and characterize neurodegeneration in ALS. Furthermore, TMS and DTI appear to have a role as complementary diagnostic biomarkers of UMN dysfunction.