Low dosages of vitamin A may cause a decrease in the total neuron number of fetal hippocampal rat cells.

OBJECTIVES: We investigated the effect of low, medium and high doses of oral vitamin A, on the number of fetal hippocampal neurons. BACKGROUND: High doses of vitamin A during pregnancy may cause embryonic malformations. There are reports about dosages that don't cause macroscopic malformations, but may cause mental and behavioral disorders. Still, quantitative morphological studies explaining this topic are lacking. METHODS: We administered oral vitamin A to pregnant rats on the 10th-12th days of pregnancy at doses of 10000, 20000, 30000, 40000, 50000, 100000 and 200000 IU/kg. We collected the fetuses on the 19th day and removed their brains. After staining with cresyl violet and immunolabeling with Tunel and Ki67 antibody, we examined the hippocampi with stereological methods. RESULTS: Vitamin A decreased hippocampal neuron numbers beginning from 20000 IU/kg. While the number of Ki67 positive cells increased with the dosage, the increase of apoptotic cells begun at the dose of 50000 IU/kg. CONCLUSION: Our study demonstrates that vitamin A, beginning from the dosage of 20000 IU/kg, is decreasing the total hippocampal neuron numbers during the critical period of embryonic brain development and that apoptosis may not be the only factor in this outcome (Tab. 1, Fig. 3, Ref. 27).

Ensemble of Convolutional Neural Networks Improves Automated Segmentation of Acute Ischemic Lesions Using Multiparametric Diffusion-Weighted MRI.

BACKGROUND AND PURPOSE: Accurate automated infarct segmentation is needed for acute ischemic stroke studies relying on infarct volumes as an imaging phenotype or biomarker that require large numbers of subjects. This study investigated whether an ensemble of convolutional neural networks trained on multiparametric DWI maps outperforms single networks trained on solo DWI parametric maps. MATERIALS AND METHODS: Convolutional neural networks were trained on combinations of DWI, ADC, and low b-value-weighted images from 116 subjects. The performances of the networks (measured by the Dice score, sensitivity, and precision) were compared with one another and with ensembles of 5 networks. To assess the generalizability of the approach, we applied the best-performing model to an independent Evaluation Cohort of 151 subjects. Agreement between manual and automated segmentations for identifying patients with large lesion volumes was calculated across multiple thresholds (21, 31, 51, and 70 cm3). RESULTS: An ensemble of convolutional neural networks trained on DWI, ADC, and low b-value-weighted images produced the most accurate acute infarct segmentation over individual networks (P < .001). Automated volumes correlated with manually measured volumes (Spearman ρ = 0.91, P < .001) for the independent cohort. For the task of identifying patients with large lesion volumes, agreement between manual outlines and automated outlines was high (Cohen κ, 0.86-0.90; P < .001). CONCLUSIONS: Acute infarcts are more accurately segmented using ensembles of convolutional neural networks trained with multiparametric maps than by using a single model trained with a solo map. Automated lesion segmentation has high agreement with manual techniques for identifying patients with large lesion volumes.

Predictors for limb loss among patient with diabetic foot infections: an observational retrospective multicentric study in Turkey.

We aimed to investigate the predictors for limb loss among patients with diabetes who have complicated skin/soft-tissue infections. In this observational study, consecutive patients with diabetic foot infection (DFI) from 17 centres in Turkey, between May 2011 and May 2013 were included. The Turkish DFI Working Group performed the study. Predictors of limb loss were investigated by multivariate analysis. In total, 455 patients with DFI were included. Median age was 61 years, 68% were male, 65% of the patients were hospitalized, 52% of the patients had used antibiotics within the last month, and 121 (27%) had osteomyelitis. Of the 208 microorganisms isolated, 92 (44.2%) were Gram-positive cocci and 114 (54.8%) were Gram-negative rods (GNR). The most common GNR was Pseudomonas; the second was Escherichia coli, with extended spectrum ß-lactamase positivity of 33%. Methicillin-resistant Staphylococcus species were found in 14% (29/208). Amputations were performed in 126/455 (28%) patients, 44/126 (34%) of these were major amputations. In multivariate analysis, significant predictors for limb loss were, male gender (OR 1.75, 95% CI 1.04-2.96, p 0.034), duration of diabetes >20 years (OR 1.9, 95% CI 1.18-3.11, p 0.008), infected ulcer versus cellulitis (OR 1.9, 95% CI 1.11-3.18, p 0.019), history of peripheral vascular disease (OR 2, 95% CI 1.26-3.27, p 0.004), retinopathy (OR 2.25, 95% CI 1.19-4.25, p 0.012), erythrocyte sedimentation rate >70 mm/hr (OR 1.6, 95% CI 1.01-2.68, p 0.05), and infection with GNR (OR 1.8, 95% CI 1.08-3.02, p 0.02). Multivariate analysis revealed that, besides the known risk factors such as male gender, duration of diabetes >20 years, infected ulcers, history of peripheral vascular disease and retinopathy, detection of GNR was a significant predictor of limb loss.

Brain imaging in patients with transient ischemic attack: a comparison of computed tomography and magnetic resonance imaging.

BACKGROUND: Brain imaging in stroke aims at the detection of the relevant ischemic tissue pathology. Cranial computed tomography (CT) is frequently used in patients with transient ischemic attack (TIA) but no data is available on how it directly compares to magnetic resonance imaging (MRI). METHODS: We compared detection of acute ischemic lesions on CT and MRI in 215 consecutive TIA patients who underwent brain imaging with either CT (n = 161) or MRI (n = 54). An MRI was performed within 24 h in all patients who had CT initially. RESULTS: An initial assessment with CT revealed no acute pathology in 154 (95.7%) and possible acute infarction in 7 (4.3%) patients. The acute infarct on CT was confirmed by diffusion-weighted imaging (DWI) in only 2 cases (28.6%). DWI detected an acute infarct in 50 of the 154 patients with normal baseline CT (32.5%). Among 54 patients without baseline CT, DWI showed acute ischemic lesions in 19 (35.2%). The ischemic lesions had a median volume of 0.87 cm(3) (range: 0.08-15.61), and the lesion pattern provided clues to the underlying etiology in 13.7%. CONCLUSION: Acute MRI is advantageous over CT to confirm the probable ischemic nature and to identify the etiology in TIA patients.

Early stroke risk and ABCD2 score performance in tissue- vs time-defined TIA: a multicenter study.

OBJECTIVES: Stroke risk immediately after TIA defined by time-based criteria is high, and prognostic scores (ABCD2 and ABCD3-I) have been developed to assist management. The American Stroke Association has proposed changing the criteria for the distinction between TIA and stroke from time-based to tissue-based. Research using these definitions is lacking. In a multicenter observational cohort study, we have investigated prognosis and performance of the ABCD2 score in TIA, subcategorized as tissue-positive or tissue-negative on diffusion-weighted imaging (DWI) or CT imaging according to the newly proposed criteria. METHODS: Twelve centers provided data on ABCD2 scores, DWI or CT brain imaging, and follow-up in cohorts of patients with TIA diagnosed by time-based criteria. Stroke rates at 7 and 90 days were studied in relation to tissue-positive or tissue-negative subcategorization, according to the presence or absence of brain infarction. The predictive power of the ABCD2 score was determined using area under receiver operator characteristic curve (AUC) analyses. RESULTS: A total of 4,574 patients were included. Among DWI patients (n = 3,206), recurrent stroke rates at 7 days were 7.1%(95% confidence interval 5.5-9.1) after tissue-positive and 0.4% (0.2-0.7) after tissue-negative events (p diff < 0.0001). Corresponding rates in CT-imaged patients were 12.8% (9.3-17.4) and 3.0% (2.0-4.2), respectively (p diff < 0.0001). The ABCD2 score had predictive value in tissue-positive and tissue-negative events (AUC = 0.68 [95% confidence interval 0.63-0.73] and 0.73 [0.67-0.80], respectively; p sig < 0.0001 for both results, p diff = 0.17). Tissue-positive events with low ABCD2 scores and tissue-negative events with high ABCD2 scores had similar stroke risks, especially after a 90-day follow-up. CONCLUSIONS: Our findings support the concept of a tissue-based definition of TIA and stroke, at least on prognostic grounds.

Severity of leukoaraiosis determines clinical phenotype after brain infarction.

OBJECTIVE: To determine whether the extent of leukoaraiosis, a composite marker of baseline brain integrity, differed between patients with TIA with diffusion-weighted imaging (DWI) evidence of infarction (transient symptoms with infarction [TSI]) and patients with ischemic stroke. METHODS: Leukoaraiosis volume on MRI was quantified in a consecutive series of 153 TSI and 354 ischemic stroke patients with comparable infarct volumes on DWI. We explored the relationship between leukoaraiosis volume and clinical phenotype (TIA or ischemic stroke) using a logistic regression model. RESULTS: Patients with TSI tended to be younger (median age 66 vs 69 years, p = 0.062) and had smaller median normalized leukoaraiosis volume (1.2 mL, interquartile range [IQR] 0.2-4.7 mL vs 3.5 mL, IQR 1.2-8.6 mL, p < 0.001). In multivariable analysis controlling for age, stroke risk factors, etiologic stroke mechanism, infarct volume, and infarct location, increasing leukoaraiosis volume remained associated with ischemic stroke (odds ratio 1.05 per mL, 95%confidence interval 1.02-1.09, p = 0.004), along with infarct volume and infarct location. CONCLUSION: The probability of ischemic stroke rather than TSI increases with increasing leukoaraiosis volume, independent of infarct size and location. Our findings support the concept that the integrity of white matter tracts connecting different parts of the brain could contribute to whether or not patients develop TSI or ischemic stroke in an event of brain infarction.

The Causative Classification of Stroke system: an international reliability and optimization study.

BACKGROUND: Valid and reliable ischemic stroke subtype determination is crucial for well-powered multicenter studies. The Causative Classification of Stroke System (CCS, available at http://ccs.mgh.harvard.edu) is a computerized, evidence-based algorithm that provides both causative and phenotypic stroke subtypes in a rule-based manner. We determined whether CCS demonstrates high interrater reliability in order to be useful for international multicenter studies. METHODS: Twenty members of the International Stroke Genetics Consortium from 13 centers in 8 countries, who were not involved in the design and development of the CCS, independently assessed the same 50 consecutive patients with acute ischemic stroke through reviews of abstracted case summaries. Agreement among ratings was measured by kappa statistic. RESULTS: The κ value for causative classification was 0.80 (95% confidence interval [CI] 0.78-0.81) for the 5-subtype, 0.79 (95% CI 0.77-0.80) for the 8-subtype, and 0.70 (95% CI 0.69-0.71) for the 16-subtype CCS. Correction of a software-related factor that generated ambiguity improved agreement: κ = 0.81 (95% CI 0.79-0.82) for the 5-subtype, 0.79 (95% CI 0.77-0.80) for the 8-subtype, and 0.79 (95% CI 0.78-0.80) for the 16-subtype CCS. The κ value for phenotypic classification was 0.79 (95% CI 0.77-0.82) for supra-aortic large artery atherosclerosis, 0.95 (95% CI 0.93-0.98) for cardioembolism, 0.88 (95% CI 0.85-0.91) for small artery occlusion, and 0.79 (0.76-0.82) for other uncommon causes. CONCLUSIONS: CCS allows classification of stroke subtypes by multiple investigators with high reliability, supporting its potential for improving stroke classification in multicenter studies and ensuring accurate means of communication among different researchers, institutions, and eras.

Functional contrast-enhanced CT for evaluation of acute ischemic stroke does not increase the risk of contrast-induced nephropathy.

BACKGROUND AND PURPOSE: Concerns have recently grown regarding the safety of iodinated contrast agents used for CTA and CTP imaging. We tested whether the incidence of AN, defined by a >or=25% increase in the post-contrast scan creatinine level, was higher among patients with ischemic stroke who underwent a functional contrast-enhanced CT protocol compared with those who had no iodinated contrast administration. MATERIALS AND METHODS: The contrast-exposed group consisted of 575 patients with acute ischemic stroke who underwent CTA (n = 313), CTA/CTP (n = 224), or CTA/CTP followed by conventional angiography (n = 38) within 24 hours of stroke onset and were consecutively enrolled in a prospective cohort study. The nonexposed group consisted of 343 patients with ischemic stroke, consecutively admitted to the same institution, who did not receive iodinated contrast material. Patients were stratified by baseline eGFR. In the primary analysis, the Fisher exact test was used to compare the incidence of AN between the contrast-exposed and the nonexposed patients at 24, 48, and 72 hours and on a cumulative basis. A secondary analysis compared the incidence of AN in patients who underwent conventional angiography following CTA/CTP versus patients who underwent CTA/CTP only. RESULTS: The incidence of AN was 5% in the exposed and 10% in the nonexposed group (P = .003). Patients who underwent conventional angiography after contrast CT were at no greater risk of AN than patients who underwent CTA/CTP alone (26 patients, 5%; and 2 patients, 5%, respectively; P = .7). CONCLUSIONS: Administration of a contrast-enhanced CT protocol involving CTA/CTP and conventional angiography in selected patients does not appear to increase the incidence of CIN.

A score to predict early risk of recurrence after ischemic stroke.

BACKGROUND: There is currently no instrument to stratify patients presenting with ischemic stroke according to early risk of recurrent stroke. We sought to develop a comprehensive prognostic score to predict 90-day risk of recurrent stroke. METHODS: We analyzed data on 1,458 consecutive ischemic stroke patients using a Cox regression model with time to recurrent stroke as the response and clinical and imaging features typically available to physician at admission as covariates. The 90-day risk of recurrent stroke was calculated by summing up the number of independent predictors weighted by their corresponding beta-coefficients. The resultant score was called recurrence risk estimator at 90 days or RRE-90 score (available at: http://www.nmr.mgh.harvard.edu/RRE-90/). RESULTS: Sixty recurrent strokes (54 had baseline imaging) occurred during the follow-up period. The risk adjusted for time to follow-up was 6.0%. Predictors of recurrence included admission etiologic stroke subtype, prior history of TIA/stroke, and topography, age, and distribution of brain infarcts. The RRE-90 score demonstrated adequate calibration and good discrimination (area under the ROC curve [AUC] = 0.70-0.80), which was maintained when applied to a separate cohort of 433 patients (AUC = 0.70-0.76). The model's performance was also maintained for predicting early (14-day) risk of recurrence (AUC = 0.80). CONCLUSIONS: The RRE-90 is a Web-based, easy-to-use prognostic score that integrates clinical and imaging information available in the acute setting to quantify early risk of recurrent stroke. The RRE-90 demonstrates good predictive performance, suggesting that, if validated externally, it has promise for use in creating individualized patient management algorithms and improving clinical practice in acute stroke care.

Severity of leukoaraiosis correlates with clinical outcome after ischemic stroke.

BACKGROUND: Leukoaraiosis (LA) is closely associated with aging, a major determinant of clinical outcome after ischemic stroke. In this study we sought to identify whether LA, independent of advancing age, affects outcome after acute ischemic stroke. METHODS: LA volume was quantified in 240 patients with ischemic stroke and MRI within 24 hours of symptom onset. We explored the relationship between LA volume at admission and clinical outcome at 6 months, as assessed by the modified Rankin Scale (mRS). An ordinal logistic regression model was developed to analyze the independent effect of LA volume on clinical outcome. RESULTS: Bivariate analyses showed a significant correlation between LA volume and mRS at 6 months (r = 0.19, p = 0.003). Mean mRS was 1.7 +/- 1.8 among those in the lowest (< or =1.2 mL) and 2.5 +/- 1.9 in the highest (>9.9 mL) quartiles of LA volume (p = 0.01). The unfavorable prognostic effect of LA volume on clinical outcome was retained in the multivariable model (p = 0.002), which included age, gender, stroke risk factors (hypertension, diabetes mellitus, atrial fibrillation), previous history of brain infarction, admission plasma glucose level, admission NIH Stroke Scale score, IV rtPA treatment, and acute infarct volume on MRI as covariates. CONCLUSIONS: The volume of leukoaraiosis is a predictor of clinical outcome after ischemic stroke and this relationship persists after adjustment for important prognostic factors including age, initial stroke severity, and infarct volume.

Neuroanatomic correlates of stroke-related myocardial injury.

BACKGROUND: Myocardial injury can occur after ischemic stroke in the absence of primary cardiac causes. The neuroanatomic basis of stroke-related myocardial injury is not well understood. OBJECTIVE: To identify regions of brain infarction associated with myocardial injury using a method free of the bias of an a priori hypothesis as to any specific location. METHODS: Of 738 consecutive patients with acute ischemic stroke, the authors identified 50 patients in whom serum cardiac troponin T (cTnT) elevation occurred in the absence of any apparent cause within 3 days of symptom onset. Fifty randomly selected, age- and sex-matched patients with ischemic stroke without cTnT elevation served as controls. Diffusion-weighted images with outlines of infarction were co-registered to a template, averaged, and then subtracted to find voxels that differed between the two groups. Voxel-wise p values were determined using a nonparametric permutation test to identify specific regions of infarction that were associated with cTnT elevation. RESULTS: The study groups were well balanced with respect to stroke risk factors, history of coronary artery disease, infarction volume, and frequency of right and left middle cerebral artery territory involvement. Brain regions that were a priori associated with cTnT elevation included the right posterior, superior, and medial insula and the right inferior parietal lobule. Among patients with right middle cerebral artery infarction, the insular cluster was involved in 88% of patients with and 33% without cTnT elevation (odds ratio: 15.00; 95% CI: 2.65 to 84.79). CONCLUSIONS: Infarctions in specific brain regions including the right insula are associated with elevated serum cardiac troponin T level indicative of myocardial injury.

Effectiveness of hyperbaric oxygen therapy in the treatment of complex regional pain syndrome.

In this double-blind, randomized, placebo-controlled study we aimed to assess the effectiveness of hyperbaric oxygen (HBO) therapy for treating patients with complex regional pain syndrome (CRPS). Of the 71 patients, 37 were allocated to the HBO group and 34 to the control (normal air) group. Both groups received 15 therapy sessions in a hyperbaric chamber. Pain, oedema and range of motion (ROM) of the wrist were evaluated before treatment, after the 15th treatment session and on day 45. In the HBO group there was a significant decrease in pain and oedema and a significant increase in the ROM of the wrist. When we compared the two groups, the HBO group had significantly better results with the exception of wrist extension. In conclusion, HBO is an effective and well-tolerated method for decreasing pain and oedema and increasing the ROM in patients with CRPS.

A new treatment modality for fibromyalgia syndrome: hyperbaric oxygen therapy.

Fibromyalgia syndrome (FMS) is characterized by longstanding multifocal pain with generalized allodynia/hyperalgesia. There are several treatment methods but none has been specifically approved for this application. We conducted a randomized controlled study to evaluate the effect of hyperbaric oxygen (HBO) therapy in FMS (HBO group: n = 26; control group: n = 24). Tender points and pain threshold were assessed before, and after the first and fifteenth sessions of therapy. Pain was also scored on a visual analogue scale (VAS). There was a significant reduction in tender points and VAS scores and a significant increase in pain threshold of the HBO group after the first and fifteenth therapy sessions. There was also a significant difference between the HBO and control groups for all parameters except the VAS scores after the first session. We conclude that HBO therapy has an important role in managing FMS.

Intracranial Haemorrhage Probably Due to an Angiographically Occult AVM after Carotid Stenting. A Case Report.

SUMMARY: Angiographically occult vascular malformations refer to cerebrovascular malformations that are not demonstrable on technically satisfactory cerebral angiography. Authors herein present a very unusual intracranial bleeding complication related to an angiographically occult vascular malformation after extracranial carotid artery stenting procedure. A 52-year-old male patient admitted to the hospital with 2 episodes of amaurosis fugax in the left eye. Cervical carotid angiography and bilateral carotid Doppler ultrasonography revealed a 98% stenosis of the left internal carotid artery just distal to the bifurcation. Post-stenting control cervical carotid angiography revealed neither any residual stenosis nor a developmental venous anomaly. The patient developed left pupil dilatation with loss of consciousness two hours after the neurovascular intervention. Emergent cranial CT showed acute subdural haematoma, intracerebral and subarachnoid haemorrhage with massive midline shift. He underwent an emergent craniotomy with left temporal lobectomy. Abnormal cortical vascular structures with prominent engorgement were remarkable over the posterior temporal cortex. Histopathological studies confirmed the diagnosis of an occult AVM. Classically, these lesions are not visualized with angiography.Our patient's cerebral angiography and MR investigations were all normal. To our knowledge this is the first case in literature in which intracranial haemorrhage (acute subdural haematoma, intracerebral haematoma, SAH) occurred due to hyperperfusion of angiographically occult vascular malformation.

Rubral tremor after thalamic infarction in childhood.

The occurrence of tremor after thalamic lesions is well known. Delayed rubral tremor secondary to bilateral thalamic infarction is a rare finding and has not been reported previously in childhood. We present two children with a combined resting-postural-kinetic tremor caused by bithalamic infarction. The first child was a male 14 months of age, and the second was a male 9 years of age. These children come from unrelated families. On hospital admission of the first patient, generalized seizures and routine electroencephalogram (EEG) findings with diffuse spike-wave discharges predominantly over the left frontal area were clinically observed, leading to the initial diagnosis of epilepsia partialis continua. However, clinical observation and video-EEG monitoring of the movements revealed nonepileptiform accompaniments, favoring the diagnosis of rubral tremor. In the second patient, EEG revealed no paroxysmal activity and was within normal limits for age. In both patients, cranial magnetic resonance imaging revealed ischemic lesions in thalami bilaterally but failed to reveal any mesencephalic lesion. These patients demonstrate that thalamic infarction can cause rubral tremor in childhood.

Localization of clinical syndromes using DWI: two examples of the "capsular" warning syndrome.

The capsular warning syndrome (CWS) is a subtype of transient ischemic attack characterized by its recurrent nature, absence of cortical signs, and high probability of early capsular stroke. Currently, standard imaging techniques have identified only internal capsule lesions in this entity. The authors present 2 cases with an otherwise typical CWS in whom a brainstem stroke was detected by diffusion-weighted imaging (DWI). DWI's ability to differentiate between acute and chronic infarcts may assist in more accurate localization of clinical syndromes.

Diffusion-weighted magnetic resonance imaging identifies the "clinically relevant" small-penetrator infarcts.

BACKGROUND: Most patients initially seen with a clinical syndrome consistent with a small-penetrator infarct (SPI) also harbor multiple, chronic, hyperintense, white matter lesions on conventional magentic resonance imaging (ie, T2-weighted image [T2WI] and fluid-attenuation inversion recovery [FLAIR] imaging). Diffusion-weighted imaging (DWI) can identify the clinically relevant "index infarction" in such circumstances, since it differentiates between acute and chronic lesions. OBJECTIVE: To determine the clinical and radiological predictors associated with misidentification of an SPI as acute using T2WI and FLAIR images in patients with an acute SPI seen on DWI. PATIENTS: Sixty-seven consecutive patients who had an SPI. METHODS: Two independent examiners, provided with brief clinical information, but blinded to DWI findings, sought a clinically appropriate lesion on T2WI and FLAIR imaging in 67 consecutive patients found to have an SPI seen on DWI. RESULTS: The index infarction based on evaluation of T2WI or FLAIR images was in a different location than the acute lesion as identified by DWI in 9 (13%) and 11 (16%) of 67 patients, respectively. Both T2WI and FLAIR imaging were rated normal in another 9% of the patients. Multivariate analysis showed that small lesion size (<10 mm) was the only predictor of misidentifying the clinically appropriate lesion on conventional magnetic resonance imaging (P<.01). CONCLUSIONS: T2-weighted imaging and FLAIR imaging fail to identify the clinically relevant SPI in almost one quarter of the patients found to have a lesion on DWI. The characteristics of DWI make it well suited for the detection of acute small infarcts. Diffusion-weighted imaging is necessary to consistently define the clinical-anatomical relations in patients initially seen with SPIs.

Diffusion-weighted imaging identifies a subset of lacunar infarction associated with embolic source.

BACKGROUND AND PURPOSE: Small infarcts in the territory of penetrator arteries were described as causing a number of distinct clinical syndromes. The vascular pathophysiology underlying such infarcts is difficult to ascertain without careful pathological study. However, the occurrence of multiple, small infarcts, linked closely in time but dispersed widely in the brain, raises the possibility of an embolic mechanism. The current study determines the frequency and clinical characteristics of patients with well-defined lacunar syndromes and the diffusion-weighted imaging (DWI) evidence of multiple acute lesions. METHODS: Sixty-two consecutive patients who presented to the emergency room with a clinically well-defined lacunar syndrome were studied by DWI within the first 3 days of admission. RESULTS: DWI showed multiple regions of increased signal intensity in 10 patients (16%). A hemispheric or brain stem lesion in a penetrator territory that accounted for the clinical syndrome ("index lesion") was found in all. DWI-hyperintense lesions other than the index lesion ("subsidiary infarctions") were punctate and lay within leptomeningeal artery territories in the majority. As opposed to patients with a single lacunar infarction, patients with a subsidiary infarction more frequently (P<0.05) harbored an identifiable cause of stroke. CONCLUSIONS: Almost 1 of every 6 patients presenting with a classic lacunar syndrome has multiple infarctions demonstrated on DWI. This DWI finding usually indicates an identifiable cause of stroke and therefore may influence clinical decisions regarding the extent of etiologic investigations and treatment for secondary prevention.

Normal diffusion-weighted MRI during stroke-like deficits.

BACKGROUND: Diffusion-weighted MRI (DWI) represents a major advance in the early diagnosis of acute ischemic stroke. When abnormal in patients with stroke-like deficit, DWI usually establishes the presence and location of ischemic brain injury. However, this is not always the case. OBJECTIVE: To investigate patients with stroke-like deficits occurring without DWI abnormalities in brain regions clinically suspected to be responsible. METHODS: We identified 27 of 782 consecutive patients scanned when stroke-like neurologic deficits were still present and who had normal DWI in the brain region(s) clinically implicated. Based on all the clinical and radiologic data, we attempted to arrive at a pathophysiologic diagnosis in each. RESULTS: Best final diagnosis was a stroke mimic in 37% and a cerebral ischemic event in 63%. Stroke mimics (10 patients) included migraine, seizures, functional disorder, transient global amnesia, and brain tumor. The remaining patients were considered to have had cerebral ischemic events: lacunar syndrome (7 patients; 3 with infarcts demonstrated subsequently) and hemispheric cortical syndrome (10 patients; 5 with TIA, 2 with prolonged reversible deficits, 3 with infarction on follow-up imaging). In each of the latter three patients, the regions destined to infarct showed decreased perfusion on the initial hemodynamically weighted MRI (HWI). CONCLUSIONS: Normal DWI in patients with stroke-like deficits should stimulate a search for nonischemic cause of symptoms. However, more than one-half of such patients have an ischemic cause as the best clinical diagnosis. Small brainstem lacunar infarctions may escape detection. Concomitant HWI can identify some patients with brain ischemia that is symptomatic but not yet to the stage of causing DWI abnormality.