Areas Of Restricted Diffusion Research Articles

P.122 Restricted diffusion of white matter in infants with subdural hematoma

Background: Inflicted head injury is a major cause of infant morbidity and mortality. The extent of traumatic brain injury in infants is often best characterized by diffusion weighted magnetic resonance imaging. In this cases series we describe four infants aged 6-19 months, with small unilateral subdural hematomas secondary to abusive head trauma accompanied by extensive areas of restricted diffusion weighted imaging isolated to the cerebral white matter. Methods: Retrospective, single-centre case series of four children with small unilateral subdural hematomas with early and delayed MR imaging with diffusion weighted imaging. Results: In three cases there was acute diffusion restriction ispilateral to the subdural, while in one case diffusion restriction was present bilaterally. All patients had multiple seizures and bilateral multilayered retinal hemorrhages. After non-surgical treatment, all patients survived albeit with significant motor and cognitive deficits and significant cortical atrophy on long-term followup imaging. Conclusions: These four cases highlight that relatively small subdural hematomas following child abuse can manifest with extensive white matter injury only evident at early stages with diffusion weighted imaging. We propose that selective white matter injury as a result of either reperfusion or axonal degeneration in response to the initial insult accounts for this novel pattern of infantile traumatic brain injury.

Clinical presentation and spectrum of neuroimaging findings in newborn infants with incontinentia pigmenti.

To report on the neurological presentation and neuroimaging findings in newborn infants with incontinentia pigmenti. The clinical and neurological course including neuroimaging and follow-up data of eight newborn infants with the neurological phenotype of incontinentia pigmenti were retrospectively reviewed. While the clinical picture was polymorphic, the neurological manifestations were defined as encephalopathic and comprised lethargy and seizures in all but one of the infants. Magnetic resonance imaging (MRI) abnormalities were predominantly in the white matter. Diffusion-weighted imaging (DWI) was obtained during the acute phase in seven of the eight infants, showing restricted diffusion in the deep and subcortical white matter but also in the corpus callosum, basal ganglia, thalami, cerebellum, and cerebral peduncles. Susceptibility-weighted imaging (SWI), performed in five infants, showed a variable amount of signal loss, mainly in the white matter, within areas of restricted diffusion. Extensive MRI abnormalities in newborn infants were followed by abnormal neurodevelopment, with significant motor, cognitive, and/or visual problems. To assess the extent of central nervous system involvement, MRI is recommended in the clinical evaluation of infants with incontinentia pigmenti. They have a characteristic pattern of brain lesions seen on MRI, best recognized using DWI and SWI in the acute neonatal phase, which allow the identification of and distinction between ischaemic and haemorrhagic lesions.

Whole brain C-arm computed tomography parenchymal blood volume measurements.

C-arm flat detector computed tomography (FDCT) parenchymal blood volume (PBV) imaging in the neuro-interventional suite is a new technique for which detailed whole brain measurements have not been previously reported. This study aims to create a catalogue of PBV measurements for various anatomical regions encompassing the whole brain, using a three-dimensional volume-of-interest (3D-VOI) analysis. We acquired and analysed 30 C-arm FDCT datasets from 26 patients with aneurysmal subarachnoid haemorrhage (SAH), as part of a prospective study comparing C-arm computed tomography (CT) PBV with magnetic resonance perfusion-weighted imaging (MR-PWI). We calculated the PBV values for various brain regions with an automated analysis, using 58 pre-defined atlas-based 3D-VOIs encompassing the whole brain. VOIs partially or completely overlapping regions of magnetic resonance diffusion weighted imaging (MR-DWI) abnormality or magnetic resonance cerebral blood flow (MR-CBF) asymmetry were excluded from the analysis. Of the 30 C-arm CT PBV datasets, 14 (54%; 12 patients) had areas of restricted diffusion, the majority of which were focal. The PBV values for the cerebral cortex and cerebral white matter were 4.01 ± 0.47 (mean ± SD) and 3.01 ± 0.39 ml per 100 ml. Lobar PBV values were: frontal lobe 4.2 ± 0.8, temporal lobe 4.2 ± 0.9, parietal lobe 3.9 ± 0.7 and occipital lobe 4.3 ± 0.8 ml/100 ml. The basal ganglia and brainstem PBV values were 3.4 ± 0.7 and 4.6 ± 0.6 ml/100 ml, respectively. Compared with the typical reference cerebral blood volume (CBV) values reported in the literature for Positron Emission Tomography (PET), the PBV values were relatively high for the white matter and relatively low for the cortical grey matter. The reported catalogue of PBV values for various brain regions would be useful to inform future studies and could be used in clinical practice, when interpreting PBV maps.

Ischemic stroke due to occlusion of the artery of Percheron.

Sir, A 60-year-old female presented with acute onset altered sensorium, vertical gaze ophthalmoparesis, side-to-side, and up-and-down 2-4 Hz head tremors that were aggravated on sitting or standing and disappeared on sleeping along with mild memory disturbances. An urgent magnetic resonance imaging (MRI) of the brain demonstrated symmetric bilateral restricted diffusion in paramedian thalami and rostral midbrain on diffusion-weighted MRI [Figures ​[Figures11 and ​and2]2] showing the “V” sign which was consistent with acute infarcts and compatible with occlusion of the artery of Percheron. Magnetic resonance angiography (MRA) showed patent posterior circulation including the tip of the basilar artery and both posterior cerebral arteries. Figure 1 Diffusion-weighted image (a) and corresponding apparent diffusion coefficient map (b) showing V-shaped area of diffusion restriction in midbrain consistent with acute infarcts Figure 2 Fluid-attenuated inversion recovery-weighted image showing symmetrical hyperintense signal in bilateral paramedian thalami which were also showing diffusion restriction and hence consistent with acute infarction The thalami and midbrain have a complex blood supply with multiple feeding arteries. The medial parts of the thalami are supplied by the perforating thalamic arteries (also named as paramedian arteries), which arise from the posterior circulation.[1,2] Percheron delineated four normal variations of the neurovascular anatomy of the thalami and midbrain. In variation II-b, the bilateral perforating thalamic arteries originate from one central artery known as the artery of Percheron, which arises from the P1 segment of one posterior cerebral artery.[3] This artery is a single trunk that provides bilateral arterial supply to the paramedian thalami and the rostral midbrain. Occlusion of this artery leads to bilateral thalamic and mesencephalic infarctions. These infarcts are typically defined by a triad of altered mental status, vertical gaze palsy, and memory deterioration. However, the clinical diagnosis is difficult in majority of the cases because the complex arterial anatomy causes large clinical variability.[4,5] Our patient presented with all the three typical features of this stroke syndrome along with head tremors. The “V” sign on MRI appears as a well-defined pattern of V-shaped hyperintensity on axial fluid-attenuated inversion recovery and/or diffusion-weighted images along the pial surface of the midbrain adjoining the interpeduncular fossa.[4] Since artery of Percheron is too small to be visualized by computed tomography angiography or MRA, the angiographic studies are frequently normal in these cases.[4] To conclude, the artery of Percheron is an uncommon entity which originates from the first segment of the posterior cerebral artery and gives rise to bilateral medial thalamic and midbrain perforators. Our patient had artery of Percheron infarct along head tremors which has not been reported before. The etiology of head tremors might be due to red nucleus involvement. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest

Appearance of Renal Replacement Lipomatosis on Computed Tomography: Rare pseudotumour.

An 81-year-old male patient presented to the Urology Department of GATA Haydarpasa Training Hospital, Istanbul, Turkey, in May 2014 complaining of left lumbar pain and a sense of abdominal fullness. On physical examination, left lumbar tenderness and a palpable mass were observed. A urine analysis showed an increased number of red blood cells. Plain abdominal radiography demonstrated soft tissue density at the left upper quadrant pushing the colon segments medially [Figure 1]. Abdominal ultrasonography revealed a significant increase in the size and echogenicity of the left kidney and its margin could not be clearly differentiated from the surrounding fat tissue. In addition, a decrease in the left renal parenchymal thickness was noted. Figure 1: Plain abdominal radiograph showing a mass with soft tissue density in the left upper quadrant pushing the colon segments medially (arrows) in a patient with renal replacement lipomatosis. Computed tomography (CT) and magnetic resonance imaging (MRI) were performed without the administration of intravenous contrast due to elevated serum creatinine levels. The CT scan [Figure 2] and axial T2-weighted MRI images revealed a fatty mass in the left kidney (approximately 22 × 18 × 14 cm in size) with areas of linear and patchy fibrous tissue. The mass caused significant enlargement of the left kidney and distortion of the surrounding structures. There were no areas of restricted diffusion within the lesion on diffusion-weighted images. A biopsy of the mass was performed and a pathological examination revealed mature fat tissue. As a result of these findings, the left renal mass was considered to indicate renal replacement lipomatosis (RRL). Ultrasonography performed three months after the initial diagnosis revealed no changes in the size and imaging characteristics of the lesion. Figure 2: Non-contrast computed tomography showing a fatty renal mass (arrows) in a patient with renal replacement lipomatosis. The mass caused significant left renal enlargement and distortion on the surrounding structures.

Paradoxical centrally increased diffusivity in perinatal arterial ischemic stroke.

Restricted diffusion on acute MRI is the diagnostic standard for perinatal arterial ischemic stroke. In a subset of children with perinatal arterial ischemic stroke, primarily those with large infarct volumes, we noted a core of centrally increased diffusivity with a periphery of restricted diffusion. Given the paradoxical diffusion-weighted imaging (DWI) appearance observed in some children with perinatal arterial ischemic stroke, we sought to determine its significance and hypothesized that: (1) centrally increased diffusivity is associated with larger infarcts in perinatal arterial ischemic stroke and (2) this tissue is irreversibly injured (infarcted). We reviewed all perinatal arterial ischemic stroke cases in a prospective cohort study from Aug. 1, 2000, to Jan. 1, 2012. Infarct volumes were measured by drawing regions of interest around the periphery of the area of restricted diffusion on DWI. The Mann-Whitney U test was used to compare means between groups. Of 25 eligible cases, centrally increased diffusivity was seen in 4 (16%). Cases with centrally increased diffusivity had larger average infarct volumes (mean 117,182 mm(3) vs. 36,995 mm(3); P = 0.008), higher average apparent diffusion coefficient (ADC) values in the infarct core (1,679 × 10(-6) mm(2)/s vs. 611 × 10(-6) mm(2)/s, P < 0.0001), and higher ADC ratio (1.2 vs. 0.5, P < 0.0001). At last clinical follow-up, children with perinatal arterial ischemic stroke and centrally increased diffusivity were more often treated for ongoing seizures (75% vs. 0%; P < 0.001) than those without. Centrally increased diffusivity was associated with larger stroke volume and the involved tissue was confirmed to be infarcted on follow-up imaging. Radiologists should be aware of this unusual appearance of perinatal arterial ischemic stroke in order to avoid underestimating infarct volume or making an incorrect early diagnosis.

Posterior Circulation Acute Stroke Prognosis Early Computed Tomography Score Using Hypointense Vessels on Susceptibility Weighted Imaging Independently Predicts Outcome in Patients with Basilar Artery Occlusion.

PurposeAppearance of hypointense vessels on susceptibility weighted imaging (SWI) has been reported to correlate with outcome in patients with ischemia of the anterior circulation. This study investigates the correlation between the appearance of hypointense vessels on SWI after recanalization therapy and outcome in patients with basilar artery occlusion.MethodsPatients with basilar artery occlusion who were treated with endovascular recanalization or intravenous alteplase and received an MRI including SWI after therapy were retrieved from the hospital database for retrospective analysis. Posterior circulation Acute Stroke Prognosis Early Computed Tomography Score (pcASPECTS) was calculated based on regions displaying hypointense vessels on SWI and compared to lesions on diffusion weighted imaging (DWI). Subsequently, SWI based pcASPECTS was correlated with outcome determined with modified Rankin Scale (mRS), categorized as favorable outcome (mRS 0-2) or unfavorable outcome (3-6).ResultsTwenty-two MRI of patients with basilar artery occlusion were analyzed. In seven out of eight areas of the pcASPECTS hypointense vessels on SWI were significantly correlated to areas of restricted diffusion on DWI. In univariate analysis median pcASPECTS on SWI was significantly higher in patients with favorable outcome (7.5 vs. 5, p=0.02). In a multivariate analysis pcASPECTS on SWI was an independent predictor of favorable outcome (OR 2.02; CI [1.02;3,99]; p=0.04).ConclusionpcASPECTS based on hypointense vessels on SWI after therapy predicts outcome in patients with basilar artery occlusion and might potentially be used as an additional imaging biomarker in the management of patients with stroke in the posterior circulation. This needs to be confirmed in larger prospective clinical trials.

C-Arm Flat Detector CT Parenchymal Blood Volume Thresholds for Identification of Infarcted Parenchyma in the Neurointerventional Suite.

C-arm flat detector CT parenchymal blood volume imaging allows functional assessment of the brain parenchyma in the neurointerventional suite. This study aimed to determine the optimal C-arm flat detector CT parenchymal blood volume thresholds for demarcating irreversibly infarcted brain parenchyma by using areas of restricted diffusion on MR imaging as a surrogate marker for infarction. Twenty-six patients with delayed cerebral ischemia following aneurysmal SAH underwent research C-arm CT parenchymal blood volume scans by using a biplane angiography system and contemporaneous MR imaging. Infarct and peri-infarct tissue VOIs and their homologous VOIs in the contralateral uninvolved hemisphere were delineated on the basis of the review of DWI, PWI, and ADC images. Voxel-based receiver operating characteristic curve analysis was performed to estimate the optimal absolute and normalized parenchymal blood volume values for demarcating the infarct voxels. For 12 patients with areas of restricted diffusion (infarct volume, 6.38 ± 7.09 mL; peri-infarct tissue volume, 22.89 ± 21.76 mL) based on the voxel-based receiver operating characteristic curve analysis, optimal absolute and normalized parenchymal blood volume thresholds for infarction were 2.49 mL/100 g (area under curve, 0.76; sensitivity, 0.69; specificity, 0.71) and 0.67 (area under curve, 0.77; sensitivity, 0.69; specificity, 0.72), respectively (P value < .01). For the moderate-to-severely ischemic peri-infarct zone, mean parenchymal blood volume values of the involved hemisphere VOIs were lower compared with the uninvolved hemisphere VOIs (P value < .01). However, for the mild-to-moderately ischemic peri-infarct zone, there was no statistically significant difference between the mean parenchymal blood volume values of the involved and uninvolved hemisphere VOIs (P value > .05). C-arm flat detector CT parenchymal blood volume maps in conjunction with optimal thresholds are sensitive and specific for the estimation of irreversibly infarcted parenchyma. Parenchymal blood volume maps allow reliable detection of moderate-to-severe ischemia; however, the potential for underestimation of mild-to-moderate ischemia exists.

PP13.3 – 2868: Dramatic neurological outcome at one year in a 4 week old with atypical haemolytic syndrome (aHUS)

A 4 week old baby presented with bloody diarrhoea and subsequent right and left focal tonic and clonic seizures. She then developed haemolytic anaemia, thrombocytopenia and acute renal failure, requiring admission to PICU. Her neurological status deteriorated with decreased consciousness, extensor/dystonic posturing, pyramidal signs bilaterally and increasing head circumference. She was diagnosed clinically with aHUS. aHUS is a rare life threatening genetic disorder caused by chronic uncontrolled complement activation. It is characterised by a systemic thrombotic microangiopathy which targets both the kidneys and brain. She was treated with Eculizumab (a monoclonal antibody) given on days 1and 8 of PICU and continues treatment on a three weekly basis. She is the first neonate treated effectively with ecluzimab to be reported in the literature. Investigations: Initial CT scan and infective screen including lumbar puncture was normal. EEG showed a discontinuous background with periods of suppression in either hemisphere. Initial MRI showed restricted diffusion in the white matter and corpus callosum, upper thalami and lentiform nucleus. Investigations out ruled congenital TTP or an infective/metabolic cause. There has been no known pathogenic mutation identified (CFH, CFI CD46, C3, CFB, DGKE, THBD, CFHR1 and CFH13 negative). Her complement factor H and factor I levels are normal and there are no antibodies for anti-factor H autoantibodies. Outcome Her neurological signs resolved dramatically after the second dose of Eculizumab (day 10 of illness). Repeat MRI scan 2 months after the initial presentation showed resolution of the areas of diffusion restriction and only mild periventricular change. Neurological examination at 16 months confirmed a normal neurodevelopmental outcome with mild central and peripheral hypotonia. Conclusion Neonatal aHUS presenting with severe neurological involvement and characteristic MRI findings (restricted diffusion in the basal ganglia and white matter) has a good neurological outcome when treated early with Eculizumab. A 4 week old baby presented with bloody diarrhoea and subsequent right and left focal tonic and clonic seizures. She then developed haemolytic anaemia, thrombocytopenia and acute renal failure, requiring admission to PICU. Her neurological status deteriorated with decreased consciousness, extensor/dystonic posturing, pyramidal signs bilaterally and increasing head circumference. She was diagnosed clinically with aHUS. aHUS is a rare life threatening genetic disorder caused by chronic uncontrolled complement activation. It is characterised by a systemic thrombotic microangiopathy which targets both the kidneys and brain. She was treated with Eculizumab (a monoclonal antibody) given on days 1and 8 of PICU and continues treatment on a three weekly basis. She is the first neonate treated effectively with ecluzimab to be reported in the literature. Investigations: Initial CT scan and infective screen including lumbar puncture was normal. EEG showed a discontinuous background with periods of suppression in either hemisphere. Initial MRI showed restricted diffusion in the white matter and corpus callosum, upper thalami and lentiform nucleus. Investigations out ruled congenital TTP or an infective/metabolic cause. There has been no known pathogenic mutation identified (CFH, CFI CD46, C3, CFB, DGKE, THBD, CFHR1 and CFH13 negative). Her complement factor H and factor I levels are normal and there are no antibodies for anti-factor H autoantibodies. Her neurological signs resolved dramatically after the second dose of Eculizumab (day 10 of illness). Repeat MRI scan 2 months after the initial presentation showed resolution of the areas of diffusion restriction and only mild periventricular change. Neurological examination at 16 months confirmed a normal neurodevelopmental outcome with mild central and peripheral hypotonia. Neonatal aHUS presenting with severe neurological involvement and characteristic MRI findings (restricted diffusion in the basal ganglia and white matter) has a good neurological outcome when treated early with Eculizumab.

Aphasia in multilingual individuals: the importance of bedside premorbid language proficiency assessment.

Aphasia in multilingual individuals: the importance of bedside premorbid language proficiency assessment.

Magnetic resonance imaging findings in patients presenting with (sub)acute cerebellar ataxia

Acute or subacute cerebellar inflammation is mainly caused by postinfectious, toxic, neoplastic, vascular, or idiopathic processes and can result in cerebellar ataxia. Previous magnetic resonance (MR) studies in single patients who developed acute or subacute ataxia showed varying imaging features. Eighteen patients presenting with acute and subacute onset of ataxia were included in this study. Cases of chronic-progressive/hereditary and noncerebellar causes (ischemia, multiple sclerosis lesions, metastasis, bleedings) were excluded. MR imaging findings were then matched with the clinical history of the patient. An underlying etiology for ataxic symptoms were found in 14/18 patients (postinfectious/infectious, paraneoplastic, autoimmune, drug-induced). In two of five patients without MR imaging findings and three of eight patients with minimal imaging features (cerebellar atrophy, slight signal alterations, and small areas of restricted diffusion), adverse clinical outcomes were documented. Of the five patients with prominent MR findings (cerebellar swelling, contrast enhancement, or broad signal abnormalities), two were lost to follow-up and two showed long-term sequelae. No correlation was found between the presence of initial MRI findings in subacute or acute ataxia patients and their long-term clinical outcome. MR imaging was more flagrantly positive in cases due to encephalitis.

Abstract T P36: DWI Lesion Size but Not FLAIR Status Alone is Associated With Early Clinical Outcome in Stroke Patients Undergoing MRI Prior to Systemic Thrombolysis

Objectives: Treatment of ischemic stroke holds the risk of intracerebral hemorrhage (ICH) due to systemic thrombolysis, often associated with poor functional outcome. Hence, parameters allowing prediction from deleterious courses are of increasing interest. We have recently shown that fluid-attenuated inversion recovery (FLAIR)-positive lesions seen on baseline magnetic resonance imaging (MRI) are associated with an increased rate on ICH. This study asked for the relationship between findings originating from baseline MRI and the clinical course. Methods: Using a multi-parameter hospital-based registry, the diffusion-weighted imaging (DWI) and FLAIR on baseline MRI of 122 ischemic stroke patients were analyzed for DWI lesion size and FLAIR-positive lesions within diffusion-restricted areas. These data originated from MRI that had been done prior to treatment with tissue plasminogen activator (tPA) within 3 hours from symptom onset, whereas computed tomography performed within 24 hours post-treatment served for detection of ICH. The early clinical outcome was assessed at hospital discharge using Barthel index (BI), modified Rankin scale (mRS) and National Institutes of Health Stroke Scale (NIHSS). Results: Out of 97 patients providing sufficient imaging quality, FLAIR-positive lesions were present in 25 patients (25.8 %) and ICH occurred in 32 patients (33.0 %). Remarkably, patients with or without FLAIR-positive lesions did not differ concerning the clinical outcome (BI, P =0.055; mRS, P =0.106; NIHSS, P =0.295). Patients exhibiting an initial DWI lesion size of at least 1/3 of vascular territory demonstrated an increased NIHSS ( P =0.031), increased mRS ( P =0.011) and decreased BI ( P =0.004) when compared to patients with smaller lesion sizes. As expected, more severe clinical affection was found in patients suffering from ICH (BI, P =0.013; mRS, P =0.001; NIHSS, P =0.016). Conclusions: In ischemic stroke patients treated with tPA, initial DWI lesion size was found to be closely associated with early clinical outcome, which was, however, not seen for FLAIR positivity. Therefore, a combination of both DWI lesion size and FLAIR status might represent an addition tool to enhance safety for stroke patients undergoing systemic thrombolysis.

Top of Basilar Artery Syndrome.

A 45 years old male presented in Department of Medicine at the Shree Shayaji General Hospital with sudden onset bilateral ptosis, dilatation of the pupil and paresis of extraocular muscles. There were area of restricted diffusion on diffusion weighted images with corresponding low ADC (Apparent Diffusion Coefficient) value in periaqueductal region, oculomotor nucleus and medial thalami suggestive of acute infract. In MR cerebral angiographic image filling defect is seen in the basilar artery suggestive of thrombosis [Table/Fig-1,​,22,​,3].3]. Top of the Basilar Artery Syndrome is also known as a Rostral Brainstem Infarction. It is due to the thromboembolic occlusion of the top of the basilar artery. Risk factors for the thrombosis are hypertension [1], diabetes mellitus [2], obesity [2], hyperhomocystinemia [3], and excessive alcohol intake. It may be secondary to the cardiogenic emboli like mural thrombi in myocardial infarction and atrial fibrillations or valvular thrombi in infective endocarditic and valvular heart disease. Hypercoaguable states like antiphospholipid antibodies [4], protein C deficiency [4], protein S deficiency [4] may also leads to the thrombotic events. Small vessel vaculities in sickle cell disease may be associated with it. Bilateral tha lamic ischemia occurs due to occlusion of perforator vessels. Clinically patient develops symptoms like visual and oculomotor deficits and behavioral abnormalities. However, motor dysfunction is often absent [5]. CT angiography, MR angiography and catheter angiographic are the imaging modality use to confirm the finding and demonstrate a filling defect [6]. Prognosis in patient with bilateral ocular palsy is poor. [Table/Fig-1a,b]: Axial section of diffusion weighted MR image shows (A) area of restricted diffusion in oculomotor nuclei region in midbrain (open white arrow) (B) area of restricted diffusion in bilateral medial thalami (open white arrow) [Table/Fig-2a,b]: Axial section of Apparent Diffusion map shows (A) corresponding low ADC value in oculomotor nuclei region in medulla (black solid arrow) (B) in bilateral medial thalami (solid white arrow) [Table/Fig-3a,b]: MR angiographic images shows filling defect in the basilar artery suggestive of thrombosis Top of the basilar artery syndrome is occurring due to thrombotic occlusion of the basilar artery. Patient presented with visual and oculomotor deficit and behaviour abnormalities. MR angiography demonstrate filling defect in the basilar artery.

Posterior Reversible Encephalopathy Syndrome (PRES): Restricted Diffusion does not Necessarily Mean Irreversibility.

SummaryBackgroundRestricted diffusion is the second most common atypical presentation of PRES. This has a very important implication, as lesions with cytotoxic edema may progress to infarction. Several studies suggested the role of DWI in the prediction of development of infarctions in these cases. Other studies, however, suggested that PRES is reversible even with cytotoxic patterns. Our aim was to evaluate whether every restricted diffusion in PRES is reversible and what factors affect this reversibility.Material/MethodsThirty-six patients with acute neurological symptoms suggestive of PRES were included in our study. Inclusion criteria comprised imaging features of atypical PRES where DWI images and ADC maps show restricted diffusion. Patients were imaged with 0.2-T and 1.5-T machines. FLAIR images were evaluated for the severity of the disease and a FLAIR/DWI score was used. ADC values were selectively recorded from the areas of diffusion restriction. A follow-up MRI study was carried out in all patients after 2 weeks. Patients were classified according to reversibility into: Group 1 (reversible PRES; 32 patients) and Group 2 (irreversible changes; 4 patients). The study was approved by the University’s research ethics committee, which conforms to the declaration of Helsinki.ResultsThe age and blood pressure did not vary significantly between both groups. The total number of regions involved and the FLAIR/DWI score did not vary significantly between both groups. Individual regions did not reveal any tendency for the development of irreversible lesions. Similarly, ADC values did not reveal any significant difference between both groups.ConclusionsPRES is completely reversible in the majority of patients, even with restricted diffusion. None of the variables under study could predict the reversibility of PRES lesions. It seems that this process is individual-dependent.

Herpes Simplex Viral Encephalitis Masquerading as a Classic Left MCA Stroke.

Objective. Stroke is a clinical diagnosis, with a history and physical examination significant for acute onset focal neurological symptoms and signs, often occurring in patients with known vascular risk factors and is frequently confirmed radiographically. Case Report. A 79-year-old right-handed woman, with a past medical history of hypertension, hyperlipidemia, and prior transient ischemic attack (TIA), presented with acute onset global aphasia and right hemiparesis, in the absence of fever or prodrome. This was initially diagnosed as a proximal left middle cerebral artery (MCA) stroke. However, CT perfusion failed to show evidence of reduced blood volume, and CT angiogram did not show evidence of a proximal vessel occlusion. Furthermore, MRI brain did not demonstrate any areas of restricted diffusion. EEG demonstrated left temporal periodic lateralized epileptiform discharges (PLEDs). The patient was empirically loaded with a bolus valproic acid and started on acyclovir, both intravenously. CSF examination demonstrated a pleocytosis and PCR confirmed the diagnosis of herpes simplex viral encephalitis (HSVE). Conclusions. HSVE classically presents in a nonspecific fashion with fever, headache, and altered mental status. However, acute focal neurological signs, mimicking stroke, are possible. A high degree of suspicion is required to institute appropriate therapy and decrease morbidity and mortality associated with HSVE.

Bright vessel appearance on arterial spin labeling MRI for localizing arterial occlusion in acute ischemic stroke.

The purpose of this study was to evaluate whether bright vessel appearance on arterial spin labeling (ASL) MRI can help localize arterial occlusion sites in patients with acute ischemic stroke. Patients who underwent MRI for suspected acute ischemic stroke, as identified by an area of restricted diffusion, were included. All images were visually analyzed for the presence or absence of (1) arterial occlusion on time-of-flight MR angiography, (2) bright vessel appearance on ASL images, and (3) susceptibility vessel sign. McNemar 2-tailed test was used to compare the sensitivities of ASL and susceptibility-weighted imaging for the detection of arterial occlusion, using MR angiography as the reference standard. ASL bright vessel appearance was significantly more common in the group with occlusion than in the group without occlusion (94% [33 of 35] versus 21% [17 of 82], respectively; P<0.001). The bright vessel appearance, when present, was seen proximal or distal to the occlusion site. The bright vessel appearance had a significantly higher sensitivity for the detection of occlusion than the susceptibility vessel sign (94% [33 of 35] versus 66% [23 of 35], respectively; P=0.002). In cases with negative MR angiography, the bright vessel appearance helped identify more additional arterial occlusions than the susceptibility vessel sign (21% [17 of 82] versus 10% [8 of 82], respectively; P=0.012). The bright vessel appearance on ASL imaging can provide an important diagnostic clue for the detection and localization of arterial occlusion sites in patients with acute ischemic stroke.

Susceptibility-weighted imaging in pediatric arterial ischemic stroke: a valuable alternative for the noninvasive evaluation of altered cerebral hemodynamics.

SWI provides information about blood oxygenation levels in intracranial vessels. Prior reports have shown that SWI focusing on venous drainage can provide noninvasive information about the degree of brain perfusion in pediatric arterial ischemic stroke. We aimed to evaluate the influence of the SWI venous signal pattern in predicting stroke evolution and the development of malignant edema in a large cohort of children with arterial ischemic stroke. A semiquantitative analysis of venous signal intensity on SWI and diffusion characteristics on DTI was performed in 16 vascular territories. The mismatch between areas with SWI-hypointense venous signal and restricted diffusion was correlated with stroke progression on follow-up. SWI-hyperintense signal was correlated with the development of malignant edema. We included 24 children with a confirmed diagnosis of pediatric arterial ischemic stroke. Follow-up images were available for 14/24 children. MCA stroke progression on follow-up was observed in 5/6 children, with 2/8 children without mismatch between areas of initial SWI hypointense venous signal and areas of restricted diffusion on DTI. This mismatch showed a statistically significant association (P = .03) for infarct progression. Postischemic malignant edema developed in 2/10 children with and 0/14 children without SWI-hyperintense venous signal on initial SWI (P = .07). SWI-DTI mismatch predicts stroke progression in pediatric arterial ischemic stroke. SWI-hyperintense signal is not useful for predicting the development of malignant edema. SWI should be routinely added to the neuroimaging diagnostic protocol of pediatric arterial ischemic stroke.

Bevacizumab: radiation combination produces restricted diffusion on brain MRI.

The purpose of this paper is to investigate the effect of bevacizumab (BEV) on the diffusion properties of irradiated brain gliomas. Neuroimaging studies and medical records of 44 patients undergoing treatment for cerebral gliomas were reviewed. MRIs were analyzed for presence of restricted diffusion, time to onset, pattern/location, duration of restriction, and persistence of restriction post-treatment with BEV. Patchy confluent areas of diffusion restriction on MRI were found in 12 patients. All 12 patients received radiation therapy followed by BEV therapy. Diffusion restriction appeared 3 to 21 months after onset of radiation and 1 to 6 months after starting BEV therapy, increased in size over time, and persisted up to 23 months while on BEV. Restricted diffusion was observed in areas that received 60 Gy or more of radiation. Areas of restricted diffusion showed low T1 and increased T2 signal intensity, minimal or no contrast enhancement, and low cerebral blood volume. A thin perimeter of susceptibility outlined the restricted areas on susceptibility-weighted images in nine patients (75%). Small focal areas of tumor recurrence within larger regions of restricted diffusion were evident in only four patients (33%). In seven patients (58%) the area of restricted diffusion showed necrosis or radiation change on histology or no metabolic activity on MR spectroscopy or PET. Restricted diffusion associated with BEV-treated cerebral gliomas occurs in regions of high-dose radiation and does not indicate high-cellularity of tumor recurrence.

A study to evaluate relationship between hematological indices and iron status with infarct size in pediatric stroke

Objectives: To evaluate the relationship between hematological indices and iron status with the infarct size, number and location in Pediatric stroke. Material and methods: Observational cross sectional study. 16 (8 Male and 8 Female) pediatric stroke patients presenting in Pediatric Neurology clinic included in the study. Hemoglobin (Hb) level, Hematocrit (HCT) and RBC indices (MCV, MCH and MCHC), platelet count and Iron status parameters (Serum Iron, TIBC and Serum Ferritin) of these patients were analysed. Area of diffusion restriction on MRI brain was measured as a surrogate marker of the severity of infarction and its correlation with RBC indices, platelet count and Iron status parameters was evaluated. Results: Mean age of studied population at presentation was 45.218±47.80 months. Mean Hb, HCT, MCV, MCH, MCHC and platelet count of these patients were 9.229±2.829gm/dl, 29.531±7.002%, 73.650 ±7.237fL, 23.650 ±.3.709pg, 30.393 ±3.000 g/dl, 331.667±201.472 x109/L respectively. Mean Serum Ferritin, TIBC and Serum Iron were 89.639 ±119.788 ng/ml, 286.125± 83.858 ug/dl, and 82.375± 59.452 ug/dl. No statistically significant correlation was seen between any of the RBC indices, Total Platelet Count and Serum Iron status indicators with mean total area of diffusion restriction in the whole cohort, in the group of patients having Serum Ferritin levels &lt;15 and &gt;15 ng/ml. Conclusion: Despite the fact that most of the literature reports association between Iron deficiency anemia with stroke, we did not find any correlation between the various RBC indices, total Platelet count and Iron status indicators with area of diffusion restriction in patients with stroke. Further studies are recommended to study the exact contributors to patho - physiology of stroke associated with Iron deficiency.DOI: http://dx.doi.org/10.3126/ajms.v6i2.10725 Asian Journal of Medical Sciences Vol.6(2) 2015 8-14

Human Parechovirus Encephalitis As an Important Differential Diagnosis of White Matter Lesions in Neonatal Sepsis-Like Illness

Human parechoviruses (HPeVs) are a family of neurotropic viruses that may cause central nervous system infection in the neonatal period, resulting in white matter lesions with a large spectrum of neurological symptoms. Common clinical presentations of infections with HPeV type 3 (HPeV3) are seizures, apnea, irritability, and lethargy. We report on a case of neonatal HPeV encephalitis, diagnosed on the basis of magnetic resonance image (MRI) findings and HPeV3 polymerase chain reaction (PCR). At the age of 4 weeks, the previously healthy infant presented with recurrent severe apnea, lethargy, and mild diarrhea. The child was irritable with the clinical symptoms of a sepsis-like neonatal infection, requiring mechanical ventilation for 7 days. Diagnostic work-up with C-reactive protein, enterovirus PCR, and metabolic tests revealed no abnormalities. CSF protein levels were elevated. MRI at the fourth day of illness revealed diffuse signal intensity changes of the white matter with multiple punctate lesions. The diffusion-weighted images showed areas of restricted diffusion in the periventricular and subcortical white matter, in particular, the frontal white matter, but also the corpus callosum, internal capsule, part of the thalamus, and pyramidal tracts of the brain stem without enhancement after contrast. The pattern of MRI involvement was suggestive of parechovirus encephalitis. HPeV3 PCR was positive in nasopharyngeal swap and stool samples. The infant gradually improved and was discharged on day 18, but developed hemiparesis with a lower limb predominance. HPeV3 should be suspected in neonates with clinical presentation of sepsis-like illness, apnoe, and CNS involvement and tested negative for enteroviruses.