Iatrogenic Spinal Subdural Hematoma due to Apixaban: A Case Report and Review of the Literature.

In the last decade, the clinical relevance for developing safer oral anticoagulants prompted the development of new classes of drugs that have shown a lower risk of life-threatening bleeding events as compared to standard warfarin. Nontraumatic spinal subdural hematoma is an uncommon urgent complication that can be associated with the use of these agents. An unusual case of spinal subdural hematoma related to apixaban treatment for nonrheumatic atrial fibrillation is reported here.

Multicentre evaluation of the INTERPRET decision support system 2.0 for brain tumour classification.

In a previous study, we have shown the added value of (1) H MRS for the neuroradiological characterisation of adult human brain tumours. In that study, several methods of MRS analysis were used, and a software program, the International Network for Pattern Recognition of Tumours Using Magnetic Resonance Decision Support System 1.0 (INTERPRET DSS 1.0), with a short-TE classifier, provided the best results. Since then, the DSS evolved into a version 2.0 that contains an additional long-TE classifier. This study has two objectives. First, to determine whether clinicians with no experience of spectroscopy are comparable with spectroscopists in the use of the system, when only minimum training in the use of the system was given. Second, to assess whether or not a version with another TE is better than the initial version. We undertook a second study with the same cases and nine evaluators to assess whether the diagnostic accuracy of DSS 2.0 was comparable with the values obtained with DSS 1.0. In the second study, the analysis protocol was flexible in comparison with the first one to mimic a clinical environment. In the present study, on average, each case required 5.4 min by neuroradiologists and 9 min by spectroscopists for evaluation. Most classes and superclasses of tumours gave the same results as with DSS 1.0, except for astrocytomas of World Health Organization (WHO) grade III, in which performance measured as the area under the curve (AUC) decreased: AUC = 0.87 (0.72-1.02) with DSS 1.0 and AUC = 0.62 (0.55-0.70) with DSS 2.0. When analysing the performance of radiologists and spectroscopists with respect to DSS 1.0, the results were the same for most classes. Having data with two TEs instead of one did not affect the results of the evaluation.

Cortical laminar necrosis related to migrainous cerebral infarction.

We present a 29-year-old woman with a long history of attacks of migraine with and without visual aura. She was a heavy smoker (20 cigarettes/d) and was currently taking oral contraceptives. During a typical migraine attack with aura, she developed dysarthria, left brachial hemiparesis and hemihypoesthesia and brief and autolimited left clonic facial movements. Four hours after onset, vascular headache and focal sensorimotor neurological deficit were the only persisting symptoms and, on seventh day, she was completely recovered. Brain magnetic resonance imaging on day 20 after onset showed a subacute ischemic lesion in the right temporo-parietal cortex compatible with cortical laminar necrosis (CLN). Extensive neurological work-up done to rule out other known causes of cerebral infarct with CLN was unrevealing. Only ten of 3.808 consecutive stroke patients included in our stroke registry over a 19-year period fulfilled the strictly defined International Headache Society criteria for migrainous stroke. The present case is the unique one in our stroke registry that presents CLN related to migrainous cerebral infarction. Migrainous infarction can result in CLN.

Lack of evidence for arterial ischemia in transient global amnesia.

BACKGROUND AND PURPOSE: Lesions in diffusion-weighted imaging (DWI-L) have been commonly described in transient global amnesia (TGA). We investigated a possible relationship between brain ischemia and TGA. METHODS: Twenty-eight patients underwent transcranial and carotid Doppler ultrasonography (including microembolus detection) and MRI within 24 hours of TGA onset (including DWI, perfusion-weighted imaging and angio-MRI). MRI was repeated at 48 to 96 hours (21 patients) and 30 days (18 patients). RESULTS: Punctate DWI-L were observed in 16 patients (57%) and were not attributable to perfusion abnormalities, arterial stenoses or underlying cardioembolic disease. MRIs performed between 12 and 72 hours showed the highest frequency of DWI-L (88%; P<0.001). No pathological findings were observed at 30 days. CONCLUSIONS: These results suggest that TGA is not related to cerebral arterial ischemia.

Safety and efficacy of intravenous tissue plasminogen activator stroke treatment in the 3- to 6-hour window using multimodal transcranial Doppler/MRI selection protocol.

BACKGROUND: Growing data point toward intravenous tissue plasminogen activator (tPA) benefit after 3 hours in selected stroke patients. We aim to study safety and efficacy of tPA treatment in the 3- to 6-hour window using multimodal transcranial Doppler (TCD)/MRI selection criteria. METHODS: We studied patients with acute middle cerebral artery (MCA) occlusion. Patients within 0 to 3 hours from symptom onset (A) were treated according to standard computed tomography criteria. Treatment within 3 to 6 hours (B) was decided according to TCD/MRI protocol. Continuous TCD assessed clot location and recanalization. National Institutes of Health Stroke Scale (NIHSS) at 24 hours assessed neurological improvement/worsening and modified Rankin score <3 functional independence at third month. RESULTS: Of 135 patients, 56 were in the 3- to 6-hour window. Only 13 (23%) patients within 3 to 6 hours did not meet MRI inclusion criteria. Finally, 122 patients were treated with tPA: A, 79 (65%); B, 43 (35%). Median time to treatment was: A, 136 minutes (range 60 to 180); B, 223 (185 to 360). There were no differences in demographic parameters, baseline NIHSS (A, 17; B, 17; P=0.89), and occlusion location (proximal MCA A, 65.8%; B, 74.4%; P=0.28). Recanalization rates at 2 hours were similar (A, 49.3%; B, 55.2%; P=0.33), as were hemorrhagic transformation rates (asymptomatic: A, 18.7%, B, 26.6%, P=0.43; symptomatic: A, 3.75%, B, 2.38%, P=0.66). Improvement at discharge was similar in both groups (NIHSS dropped 6.3 points [A] versus 6.1 [B]; P=0.86). However, the number of patients who benefited from treatment was slightly higher in the 3- to 6-hour group (A, 58.2%; B, 76.2%; P=0.05), whereas the same rate of patients worsened (A, 11.4%; B, 7.1%; P=0.46). At 3 months, the rate of independent patients was: A, 42% versus B, 38% (P=0.74). CONCLUSIONS: tPA treatment can be safely and effectively extended to the 3- to 6-hour window using TCD/MRI selection criteria. Not using these criteria in the 3- to 6-hour window avoids potentially effective treatment in a high rate of patients.

Hyperacute ischemic stroke: middle cerebral artery susceptibility sign at echo-planar gradient-echo MR imaging.

PURPOSE: To evaluate the accuracy of echo-planar T2*-weighted magnetic resonance (MR) sequences in detection of acute middle cerebral artery (MCA) or internal carotid artery (ICA) thrombotic occlusion. MATERIALS AND METHODS: Forty-two consecutive patients with stroke involving the MCA territory underwent MR imaging within 6 hours after clinical onset. MR examination included echo-planar T2*-weighted, diffusion-weighted (DW), and perfusion-weighted (PW) imaging and MR angiography. Presence or absence of the susceptibility sign on echo-planar T2*-weighted images, which is indicative of acute thrombotic occlusion involving MCA or ICA, was assessed in consensus by two observers blinded to clinical information and other MR imaging data. Differences in lesion volume on DW and PW images between patients with and those without the susceptibility sign were evaluated with the Mann-Whitney test. P <.05 was considered to indicate a significant difference. RESULTS: Thirty patients (71%) had a positive susceptibility sign that correlated with MCA or ICA occlusion at MR angiography in all cases (sensitivity, 83%; specificity, 100%). Mean lesion volume on PW images was higher in patients with a positive susceptibility sign (P =.01), but no significant differences were found in mean lesion volume on DW images. Cases in which the susceptibility sign was identified proximal to MCA divisional bifurcation (27 patients) showed a mean perfusion deficit of 83.9% of the total MCA territory (range, 50%-100%). CONCLUSION: Presence of the susceptibility sign proximal to MCA bifurcation provides fast and accurate detection of acute proximal MCA or ICA thrombotic occlusion.

Prediction of early neurological deterioration using diffusion- and perfusion-weighted imaging in hyperacute middle cerebral artery ischemic stroke.

BACKGROUND AND PURPOSE: Early neurological deterioration (END) occurs in approximately one third of all ischemic stroke patients and is associated with a poor outcome. Our study sought to assess the value of ultra-early MRI in the prediction of END in stroke patients. METHODS: Between August 1999 and November 2001, 38 stroke patients with a proven middle cerebral artery (MCA) or intracranial internal carotid artery (ICA) occlusion on MR angiography underwent perfusion-weighted imaging (PWI) and diffusion-weighted imaging (DWI) within 6 hours after onset, and 30 fulfilled all inclusion criteria. Control DWI and MR angiography were performed between days 3 and 5. Cranial CT was performed to rule out hemorrhagic transformation. Vascular risk factors, temperature, blood pressure, glycemia, and blood count were assessed on admission. National Institutes of Health Stroke Scale (NIHSS) scores were obtained at baseline and at 6, 12, 24, and 48 hours. At the same time points, transcranial Doppler (TCD) examinations were conducted to assess arterial recanalization. END was defined as an increase in the NIHSS score >4. A logistic regression model was applied to detect independent predictors of END. The Kruskal-Wallis test was used to evaluate the relationship between infarct growth and duration of vessel occlusion. RESULTS: Initial MR angiography showed an occlusion of intracranial ICA in 7 patients (23.3%), of proximal MCA in 14 (46.6%), and of distal MCA in the remaining 9 (30%). A PWI-DWI mismatch >20% was observed in 28 patients (93.3%). END occurred in 7 patients (23.3%). Baseline NIHSS score (P=0.05), proximal site of occlusion (P=0.002), initial DWI (P=0.002) and PWI (P=0.003) volumes, and reduced PWI-DWI mismatch (P=0.038) were associated with END in the univariate analysis. Only hyperacute DWI volume remained as a predictor of END when a logistic regression model was applied (odds ratio, 11.5; 95% CI, 2.31 to 57.10; P=0.0028). A receiver operator characteristic curve identified a cutoff point of DWI >89 cm(3) (sensitivity, 85.7%; specificity, 95.7%) to predict END. A graded response was seen in DWI lesion expansion in relation to duration of arterial occlusion (P=0.017). CONCLUSIONS: Ultra-early DWI is a powerful predictor of END after MCA or intracranial ICA occlusion.

Serial proton spectroscopy, magnetization transfer ratio and T 2 relaxation in pseudotumoral demyelinating lesions.

In some rare cases, demyelinating plaques appear on contrast-enhanced T1-weighted images as pseudotumoral, cyst-like lesions (hypointense, ring enhancing). Serial proton MR spectroscopy, T2 relaxometry and magnetization transfer ratios (MTR) were performed on three pseudotumoral demyelinating lesions to obtain information about their pathological basis. Baseline and 1-month MTR and T2 values were similar to those of cerebrospinal fluid, while spectra showed lactate, lipids and choline. Three-month and 1 year exams showed recovery of MTR, T2 and N-acetylaspartate, approaching the contralateral values, while creatine and choline were normal or surpassed contralateral values. Lipids and lactate gradually disappeared. These results suggest that pseudotumoral, cyst-like, ring-enhancing lesions may be characterized by an accumulation of oedema in the extracellular space with an almost complete absence of cells. Reduction of the oedema allows restoration of the tissue to its original location, indicating that cellular destruction was less important than was expected after the first exam. Thus, the evolution of this kind of lesion should be kept in mind when considering lesion volume from T1-weighted images as a marker of disability or irreversible cellular destruction in MS.

Serial diffusion-weighted MR imaging and proton MR spectroscopy of acute large demyelinating brain lesions: case report.

We present the serial MR studies of two patients with symptomatic acute large demyelinating lesions that initially showed a drop in apparent diffusion coefficient values. Baseline proton MR spectroscopy showed a slight decrease in N-acetylaspartate and a normal choline level. An excess of lactate was observed at the first examinations and completely disappeared by the final examinations. The time-course evolution of the lesions shown by MR imaging and proton MR spectroscopic examinations suggests that the initial drop in apparent coefficient diffusion may have been related to dense inflammatory cell infiltration and scant tissue destruction or to reversible reduced vascular supply due to the severity of the inflammatory process.

Diffusion-weighted MR imaging in the acute phase of transient ischemic attacks.

BACKGROUND AND PURPOSE: Radiologic assessment of acute transient ischemic attacks (TIAs) has been handicapped by the low sensitivity of CT and conventional MR imaging for acute small-vessel infarction and the difficulty in differentiating between acute and chronic lesions by use of these methods. Our purpose was to evaluate the incidence of TIA-related infarction by using diffusion-weighted MR imaging to determine whether the presence of a diffusion imaging abnormality correlates with the duration of symptoms or cause of TIA. METHODS: We prospectively studied 58 consecutive patients with acute TIA by use of diffusion-weighted imaging. All MR imaging was performed with a 1.5-T whole-body system with 24-mT/m gradient strength and an echo-planar-capable receiver. All patients were imaged within 10 days of stroke onset. RESULTS: Thirty-nine patients (67%) manifested a diffusion imaging abnormality consistent with acute ischemia. Cortical lesions were identified in 54% of these patients; most of them associated with other acute ischemic lesions. Subcortical lesions were identified in 46%; most of them were isolated from other lesions. The mean duration of symptoms in patients with no TIA-related diffusion imaging abnormalities was 0.96 hours (median, 0.33 hours) compared with a mean of 6.85 hours (median, 1.53 hours) in patients with diffusion imaging abnormalities (P =.025, Mann-Whitney U test). This significant correlation between the duration of TIA symptoms and the presence of TIA-related abnormalities was lost when we excluded from the analysis patients whose symptoms lasted longer than 6 hours (P =.513, Mann-Whitney U test). No significant correlation was observed between the size of TIA-related lesions and the duration of symptoms or cause of TIA. CONCLUSION: Two thirds of our TIA patients showed focal abnormalities indicative of acute ischemic lesions on diffusion-weighted images. This incidence is higher than that previously reported in the literature. The presence of such abnormalities increased with increasing total symptom duration, but this relation was not observed when only patients whose symptoms lasted less than 6 hours were considered. No significant correlation was observed between the cause and presence of TIA-related lesions on diffusion-weighted MR images. These TIA-related lesions are probably irreversible and may lead to subsequent infarct.

Conversión a esclerosis múltiple clínicamente definida tras un síndrome medular aislado: valor de la resonancia magnética craneal y medular / Conversion to clinically definite multiple sclerosis after isolated spinal cord syndrome: value of brain and spinal MRI

FUNDAMENTO: Los síndromes medulares aislados (SMA) pueden ser el primer brote de esclerosis múltiple. El objetivo del presente estudio fue evaluar las características clínicas, paraclínicas y la utilidad de la resonancia magnética (RM) medular y craneal para predecir la conversión a esclerosis múltiple clínicamente definida (EMCD) en pacientes con un SMA. PACIENTES Y MÉTODO: Evaluamos a 38 pacientes con un SMA. Se practicó un protocolo clínico, así como pruebas paraclínicas y RM craneal y medular.RESULTADOS: El 42,8 por ciento de los pacientes que cumplían los criterios diagnósticos de la RM craneal de Paty (p < 0,01), el 54,5 por ciento de los que tenían criterios de Fazekas (p = 0,007) y el 80 por ciento de los que cumplían criterios de Barkhof (p = 0,009) presentaron conversión a EMCD. La RM medular fue patológica en todos los pacientes que convirtieron a EMCD, presentando un predominio de localización cervical, con afección marginal y diámetro menor de 2 cm.CONCLUSIONES: La RM craneal permite detectar a pacientes con un alto riesgo de desarrollar una EMCD y la RM medular aumenta la sensibilidad de conversión a EMCD (AU)