Practice enhancements with FastStroke ColorViz analysis in acute ischemic stroke.

In acute ischemic stroke (AIS), large vessel occlusion (LVO) and the status of pial collaterals are important factors in decision-making for further treatment such as endovascular therapy. Multiphasic CT Angiogram (mCTA) is the mainstay of AIS imaging, allowing detection of LVO, evaluation of intracranial arterial dynamics, and quantification of pial collaterals. However, thorough mCTA evaluation entails scrutiny of multiple image datasets, individually and then simultaneously, which can be time-consuming, causing a potential delay in treatment. ColorViz (FastStroke, GE Healthcare, Milwaukee, Wisconsin) is a novel CT application which combines mCTA information into a single color-coded dataset for quick, unequivocal evaluation of pial collaterals. In our practice, ColorViz is both time-saving and increases the diagnostic accuracy of LVO and pial collaterals as well as medium vessel, multivessel and posterior circulation occlusions. In this article, we discuss the practical aspects of ColorViz in patients presenting with AIS.

Detecting the Uncommon Imaging Manifestations of Posterior Reversible Encephalopathy Syndrome (PRES) in Adults: a Comprehensive Illustrated Guide for the Trainee Radiologist.

Posterior reversible encephalopathy syndrome (PRES) has traditionally been described as a reversible leukoencephalopathy with a distinct pattern of posteriorly distributed vasogenic oedema involving the subcortical regions of parietal and occipital lobes. PRES commonly occurs in the setting of hypertensive emergencies, pre-eclampsia/eclampsia, impaired renal function, and immunosuppressive therapy. The various clinical presentations of PRES include encephalopathy, seizures, headache, visual, and focal neurological deficits. As knowledge of this entity grows, the range of clinical, and radiological features is seen to be much broader than originally described. The brain oedema may not always be posteriorly distributed and the syndrome may not be uniformly reversible. Of special note are some uncommon imaging features (unilateral cerebral involvement, and isolated posterior fossa involvement) and also some uncommon complications (haemorrhage, cytotoxic oedema, and vasoconstriction). These red herrings may lead to potential diagnostic challenges and pitfalls especially for trainee radiologists, who often read these scans in an emergency setting. Early and accurate diagnosis is crucial for prompt optimum management, thereby avoiding residual morbidity. This review article focusses on the atypical radiological features of PRES in adults with extensive case-based imaging examples. A brief description of the pathophysiology, clinical, and classic radiological features of PRES has also been included. A tabulated summary of potential mimics with diagnostic pearls is provided to highlight pertinent take home points and to serve as an easy guide for day-to-day clinical practice.

Pearls and Pitfalls in the Magnetic Resonance Diagnosis of Dural Sinus Thrombosis: A Comprehensive Guide for the Trainee Radiologist.

Dural sinus thrombosis (DST) is a potentially fatal neurological condition that can be reversed with early diagnosis and prompt treatment. Non-enhanced CT scan is often the first imaging investigation in patients presenting with acute neurological symptoms; however, its poor sensitivity in detecting DST is a major drawback. Magnetic resonance (MR) imaging offers multiple advantages such as excellent contrast resolution and unenhanced venography possibilities, making it the mainstay in the non-invasive diagnosis of DST. However, physiological variations, evolution of thrombi, and incorrect selection/application of MR techniques can lead to false positive and false negative interpretations impacting patient management and outcome. This article discusses the MR techniques useful to diagnose DST and describes pitfalls, with troubleshooting methods, to ensure an accurate diagnosis. We have used multiple diagrammatic illustrations and MR images to highlight pertinent take-home points and to serve as an easy guide for day-to-day clinical practice.

Neurocysticercosis Diagnosed by Taenia solium PCR on Brain Biopsy.

Neurocysticercosis is a common cause for brain lesions and adult-onset epilepsy in endemic countries. However, diagnosis is challenging in the absence of typical radiologic or histopathologic features. In this case report, we present a case of a 35-year-old male with a new-onset seizure and a rim-enhancing temporal lobe lesion. Radiologic features were nonspecific, and brain biopsy was performed. Histologic features showed only nonspecific granulomatous inflammation, and the diagnosis of neurocysticercosis was confirmed only with polymerase chain reaction (PCR) testing on brain biopsy tissue demonstrating PCR products consistent with Taenia solium. This case highlights the diagnostic role of PCR in such clinical situations whereby the diagnosis is unclear after initial routine evaluation.

Acute subdural haemorrhage complicating cerebral venous thrombosis in a patient with protein C deficiency.

Cerebral venous thrombosis (CVT) directly causing subdural haemorrhage (SDH) is a rare entity. We present a case of an 18-year-old female patient who presented with severe occipital headache. Neuroimaging showed acute SDH and CVT. She was eventually discovered to have underlying protein C deficiency. She was treated with anticoagulation and made an uneventful recovery. We aim to highlight the epidemiology, risk factors and aetiopathogenesis of CVT. We have included a literature review of previously described 13 case studies/reports describing SDH associated with CVT and a brief discussion of the dilemmas associated with management.

Adult-onset diffuse leukoencephalopathy with axonal spheroids and pigmented glia presenting with acute stroke-like symptoms: A rare clinical scenario.

Adult-onset diffuse leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) is a rare progressive degenerative white matter disease caused by mutations in the colony-stimulating factor-1 receptor gene. Patients commonly present in the 4th or 5th decade with variable clinical presentations including behavioral changes, dementia, parkinsonism, and motor dysfunctions, eventually leading to death within a few years. Although the disease is typically hereditary, sporadic cases are known to occur. The classic MRI features of ALSP include T2 hyperintensities in the frontal and parietal white matter, scattered foci of restricted diffusion in the white matter, age-advanced cerebral involutional changes, thinning and signal changes in the corpus callosum, absence of infratentorial involvement and lack of enhancement. CT commonly shows tiny calcifications in the corpus callosum and deep white matter. We report a unique case of sporadic ALSP that initially presented as young stroke with acute onset of left-sided hemiparesis and no preceding history of cognitive decline. However, subsequent cognitive and behavioral changes lead to the consideration of an alternative diagnosis. Stroke-like symptoms is a very rare primary presentation of this disease entity. We have highlighted the classic MRI and CT features that helped to guide its diagnosis in our patient and prompted early corroborative genetic testing.

Enterovirus-related rhombencephalitis and myelitis in the third trimester of pregnancy: A case report highlighting clinico-radiological findings at diagnosis and follow-up.

Rhombencephalitis (RE) refers to inflammatory diseases involving the brainstem and cerebellum. Although RE is a rare entity, it is associated with high morbidity and mortality. The management of such patients is often challenging in terms of identifying the etiology and defining prognosis. Infections, autoimmune and paraneoplastic conditions are commonly implicated. Patients with RE often present with a biphasic illness with an initial flu-like syndrome followed by brainstem dysfunction. CSF pleocytosis, abnormal brain MRI findings, isolation of organism or molecular (PCR/antigen) detection in CSF/blood cultures/stool samples and nasal/rectal swabs help in arriving at a definitive or probable diagnosis. Prompt aggressive treatment with antibacterial and antiviral drugs and/or immunoglobulins along with supportive therapy is crucial for avoiding a poor outcome. We present a case report of a 28-year old female patient who developed RE and myelitis in the third trimester of pregnancy. We aim to highlight the highly suggestive radiological findings which corroborated with the clinical diagnosis of enterovirus infection. The patient's radiological follow-up and neurological sequalae are also described. To the best of our knowledge, ours is the first report which describes the MRI features of this clinical scenario in the third trimester of pregnancy, and also the subsequent clinico-radiological follow up.

Gyriform restricted diffusion in adults: looking beyond thrombo-occlusions.

Gyriform restricted diffusion (GRD) refers to hyperintense signal involving the cerebral cortex on diffusion-weighted images (DWI) with corresponding hypointensity on apparent diffusion coefficient (ADC) images. These changes are commonly seen following a vascular occlusion, reflecting the limitation of water molecule movement across cell membranes (restricted diffusion) due to the failure of Na+/K+-ATPase pumps (cytotoxic oedema). However, GRD can occur in several other neurological conditions as well. A thorough understanding of these conditions and their anatomic predilection plays a critical role in identifying and differentiating them from vascular thrombo-occlusion, with impact towards appropriate clinical management. This review highlights the less commonly encountered, non-stroke causes of GRD in adults with case-based examples. A tabulated chart of the patterns of cortical and subcortical involvement associated with these aetiologies is provided for a quick, pattern-based reference for daily radiological reporting.

Extradural cervical spinal meningioma mimicking malignancy.

The vast majority of intraspinal meningiomas occur in an intradural extramedullary location. A meningioma in a purely extradural location in the cervical spine as reported here is quite exceptional. Extradural meningiomas tend to show more aggressive features than intradural meningiomas and are often confused with malignant neoplasms. We report an invasive extradural meningioma in the cervical spine with multi-segmental involvement, extension through the neural foramina and encasement of the subjacent vertebral artery, mimicking malignancies such as lymphoma and sarcoma. Although rare, meningiomas may demonstrate extradural multi-segmental growth and should be considered in the differential diagnosis of such lesions.

Influence of diabetes mellitus on longitudinal atrophy and cognition in Parkinson's disease.

OBJECTIVE: To investigate the impact of diabetes mellitus (DM) on cognitive performance and longitudinal volumetric brain changes in a cohort of cognitively normal mild PD patients. METHODS: Prospective study of idiopathic PD subjects who underwent baseline and follow-up MRI imaging and neuropsychological assessments at 6month intervals for 3years. Subjects were classified based on the presence (PD-DM) or absence of DM (PD-No DM) at baseline. Volumetric analysis was performed using FreeSurfer 5.3 image analysis suite. Brain volume and cognition were compared and analyzed cross-sectionally and longitudinally. Analyses were corrected for intracranial volume. RESULTS: There were 65 PD-no DM and 12 PD-DM subjects at baseline with comparable global cognition at baseline. PD-DM subjects had lower cortical grey matter (GM), amygdala, frontal white matter and temporal white matter volumes and higher total white matter hyperintensity and periventricular hyperintensities. After mean follow-up of 29.08months, there were 51 PD-no DM and 11 PD-DM subjects. PD-DM subjects demonstrated greater decline in MMSE and MOCA scores compared to PD-No DM. PD-DM subjects had a higher rate of atrophy in the cortical WM, particularly in the parietal and occipital white matter. CONCLUSION: Mild PD patients with DM have lower GM and WM volumes at baseline and higher WMH volumes, despite comparable cognitive scores. Longitudinally, DM in PD results in greater rate of cognitive decline, associated with higher WM atrophy.

Hemispheric lateralization abnormalities of the white matter microstructure in patients with schizophrenia and bipolar disorder.

BACKGROUND: Hemispheric lateralization of the brain occurs during development and underpins specialized functions. It is posited that aberrant neurodevelopment leads to abnormal brain lateralization in individuals with psychotic illnesses. Here, we sought to examine whether white matter hemispheric lateralization is abnormal in individuals with the psychotic spectrum disorders of schizophrenia and bipolar disorder. METHODS: We examined the white matter microstructure lateralization in patients with schizophrenia, bipolar disorder with psychotic features and healthy controls by measuring the laterality indices of fractional anisotropy (FA) and mean diffusivity (MD). We also correlated the laterality indices with clinical measures. RESULTS: We included 150 patients with schizophrenia, 35 with bipolar disorder and 77 healthy controls in our analyses. Shared FA lateralization abnormalities in patients with schizophrenia and bipolar disorder were found in the cerebral peduncle and posterior limb of internal capsule, with more extensive abnormalities in patients with bipolar disorder than in those with schizophrenia. The shared MD lateralization abnormalities were more widespread, extending to the subcortical, frontal-occipital, limbic and callosal tracts, with patients with bipolar disorder showing greater abnormalities than patients with schizophrenia. While lateralization was decreased in patients with schizophrenia, the lateralization was reversed in those with bipolar disorder, underpinned by the more pronounced microstructural abnormalities in the right hemisphere. The loss of FA lateralization in patients with schizophrenia was associated with lower quality of life and psychosocial functioning. LIMITATIONS: Owing to the cross-sectional study design, we cannot confirm whether the lateralization abnormalities are neurodevelopmental or a consequence of psychosis onset or chronicity. CONCLUSION: Shared and distinct white matter lateralization abnormalities were found in patients with schizophrenia and bipolar disorder. In distinct regions of abnormalities, the lateralization was attenuated in patients with schizophrenia and reversed in those with bipolar disorder.

Associations of hippocampal subfields in the progression of cognitive decline related to Parkinson's disease.

OBJECTIVE: Hippocampal atrophy has been associated with mild cognitive impairment (MCI) in Parkinson's disease (PD). However, literature on how hippocampal atrophy affects the pathophysiology of cognitive impairment in PD has been limited. Previous studies assessed the hippocampus as an entire entity instead of their individual subregions. We studied the progression of cognitive status in PD subjects over 18 in relation to hippocampal subfields atrophy. METHODS: 65 PD subjects were included. Using the MDS task force criteria, PD subjects were classified as either having no cognitive impairment (PD-NCI) or PD-MCI. We extended the study by investigating the hippocampal subfields atrophy patterns in those who converted from PD-NCI to PD-MCI (PD-converters) compared to those who remained cognitively stable (PD-stable) over 18 months. Freesurfer 6.0 was used to perform the automated segmentation of the hippocampus into thirteen subregions. RESULTS: PD-MCI showed lower baseline volumes in the left fimbria, right CA1, and right HATA; and lower global cognition scores compared to PD-NCI. Baseline right CA1 was also correlated with baseline attention. Over 18 months, decline in volumes of CA2-3 and episodic memory were also seen in PD-converters compared to PD-stable. Baseline volumes of GC-DG, right CA4, left parasubiculum, and left HATA were predictive of the conversion from PD-NCI to PD-MCI. CONCLUSION: The findings from this study add to the anatomical knowledge of hippocampal subregions in PD, allowing us to understand the unique functional contribution of each subfield. Structural changes in the hippocampus subfields could be early biomarkers to detect cognitive impairment in PD.

Diffusion-weighted MRI abnormalities in an outbreak of Streptococcus agalactiae Serotype III, multilocus sequence type 283 meningitis.

PURPOSE: In 2015, an outbreak of group B streptococcal (GBS) infection caused by Streptococcus agalactiae Serotype III, multilocus sequence type 283, related to consuming infected raw freshwater fish, affected more than 200 patients in Singapore. We describe the clinical, laboratory, and neuroimaging features of a subgroup of adults with central nervous system (CNS) infections caused by GBS. MATERIALS AND METHODS: The database of the Singapore Neurologic Infections Program (SNIP), a national multicenter study for surveillance of infectious neurologic disease, was reviewed to select patients with GBS CNS infection during the outbreak. Cases were diagnosed on the basis of clinical features, cerebrospinal fluid (CSF) findings and identification or isolation of Streptococcus agalactiae in the blood or CSF. Demographic, clinical and neuroradiological information was obtained prospectively and retrospectively abstracted. RESULTS: Fourteen patients (6 male, 8 female; median age, 58 years) presented with fever, meningism, headache, encephalopathy, focal neurological deficits, and/or seizures. All except two were previously healthy. Diffusion-weighted imaging (DWI) on admission was abnormal in 13 patients, showing tiny hyperintensities in the subarachnoid space (7 patients), ventricles (6 patients) and brain parenchyma (8 patients); 5 patients had cerebellar abnormalities. CONCLUSION: Among healthy non-pregnant adults infected with Serotype III, multilocus sequence type 283 GBS meningitis linked to eating infected raw freshwater fish, DWI detected small pus collections and unusual cerebellar involvement. A collaborative national surveillance system that includes MRI can be helpful during unusual food-borne zoonotic infectious disease outbreaks. LEVEL OF EVIDENCE: 4 J. Magn. Reson. Imaging 2017;45:507-514.

The impact of genome wide supported microRNA-137 (MIR137) risk variants on frontal and striatal white matter integrity, neurocognitive functioning, and negative symptoms in schizophrenia.

Although genome wide association studies have highlighted MicroRNA 137 (MIR137) as a novel susceptibility gene for schizophrenia, the mechanisms by which MIR137 risk variants mediate the neurobiology of schizophrenia are not clear. Based on extant data linking MIR 137 gene with structural brain anomalies and functional brain activations in schizophrenia, we hypothesized that MIR137 risk variants rs1625579 and rs1198588 would be associated with reduced fractional anisotropy in frontostriatal brain regions, impaired neurocognitive functioning and worse psychotic symptoms in schizophrenia patients compared with healthy controls. A total of 147 Chinese participants (84 patients with DSM-IV diagnosis of schizophrenia (SCZ) and 63 healthy controls (HC)) were genotyped using blood samples and underwent diffusion tensor imaging. Neurocognitive domains and psychotic symptoms were assessed using The Brief Assessment of Cognition Battery for Schizophrenia and Positive and Negative Syndrome Scale respectively. We found significant diagnosis-genotype interactions in the right orbitofrontal regions (rs1625579: F = 5.44, P = 0.021; rs1198599: F = 7.55, P = 0.005), left striatum (rs1625579: F = 8.09, P=0.007; rs1198599: F=9.56, P = 0.002), and negative symptoms (rs1625579: t = 2.45, P = 0.016; rs1198588: t = 2.29, P = 0.024). Specifically, SCZ carrying the risk TT genotype had worse negative symptoms and decreased FA in the fronto-striatal regions compared to G and A allele carriers for rs1625579 and rs1198588 respectively, and worse attention and processing speed compared with G-allele for rs1625579. Our findings suggested that the MI137 risk variants were associated with decreased fronto-striatal brain white matter integrity which may underlie poorer attention, processing speed, and greater negative symptoms in schizophrenia.

CACNA1C genomewide supported psychosis genetic variation affects cortical brain white matter integrity in Chinese patients with schizophrenia.

OBJECTIVE: Recent genomewide association studies have implicated the calcium channel, voltage-dependent, L type, alpha 1C subunit (CACNA1C) genetic variant in schizophrenia, which is associated with functional brain changes and cognitive deficits in healthy individuals. However, the impact of CACNA1C on brain white matter integrity in schizophrenia remains unclear. On the basis of prior evidence of CACNA1C-mediated changes involving cortical brain regions, we hypothesize that CACNA1C risk variant rs1006737 is associated with reductions of white matter integrity in the frontal, parietal, and temporal regions and cingulate gyrus. METHOD: A total of 160 Chinese participants (96 DSM-IV-diagnosed patients with schizophrenia and 64 healthy controls) were genotyped by using blood samples and underwent structural magnetic resonance imaging and diffusion tensor imaging scans from 2008 to 2012. Two-way analysis of covariance was employed to examine CACNA1C-related genotype effects, diagnosis effects, and genotype × diagnosis interaction effects on fractional anisotropy (FA) of relevant brain regions. RESULTS: Significant diagnosis-genotype interactions were observed (left frontal lobe mean FA: F1,156 = 6.22, P = .014; left parietal lobe mean FA: F1,156 = 7.14, P = .008; left temporal lobe mean FA: F1,156 = 8.37, P = .004). Compared with patients who were A carriers, patients who were G homozygotes had lower mean FA in the left frontal lobe (F1,93 = 2.504, P = .014), left parietal lobe (F1,93 = 2.37, P = .020), and left temporal lobe (F1,93 = 3.01, P = .003), with standardized effect sizes of -1.43, -1.3, and -1.0, respectively. CONCLUSIONS: CACNA1C risk variant rs1006737 affects cortical white matter integrity in schizophrenia. Further imaging genetic investigations on the mediating effect of CACNA1C in schizophrenia can uncover brain circuitries involved in schizophrenia and suggest potential novel targets for intervention.

Hippocampal volume and white matter disease in the prediction of dementia in Parkinson's disease.

BACKGROUND: Longitudinal neuroimaging studies could provide insights into pathophysiology of cognitive impairment in PD. We examined the role of hippocampal atrophy and cerebral white matter disease as risk factors for mild cognitive impairment and dementia in PD. METHODS: Prospective longitudinal study of patients with mild PD in a tertiary neurology center. All subjects underwent baseline MRI brain and had baseline and 6 monthly cognitive evaluations. Cognitive impairment was diagnosed based on the Movement Disorder Society Criteria. The predictive role of hippocampal volume and white matter hyperintensity at baseline on progression of cognitive impairment was studied. RESULTS: 97 subjects with mean age 65.3 years, mean education of 10.3 years and mean Hoehn & Yahr of 1.9 were studied. Over 2 years, 16 subjects developed mild cognitive impairment and 8 subjects with mild cognitive impairment progressed to dementia. After adjusting for age and vascular risk factors, hippocampal volume was a significant predictor for mild cognitive impairment (OR 7.05, CI 1.5-34.1; p = 0.015) and dementia (OR 7.03, CI 2.39-25.2; p = 0.001). With Cox regression, hippocampal volume was a significant predictor for "time to cognitive impairment" (HR 7.67; CI 3.47-16.95, p < 0.001). Difference between survival curves based on volume of white matter hyperintensity in predicting "time to mild cognitive impairment" was significant (p = 0.0295). CONCLUSIONS: Hippocampal volume is a major factor predicting the development of mild cognitive impairment and dementia in PD. White matter hyperintensity also contributes to the longitudinal cognitive status in PD.