Validation of a Simple Clinical Tool for Screening of Acute Lacunar Stroke - a substudy of the WAKE-UP trial

INTRODUCTION

Lacunar stroke represents around a quarter of all ischemic strokes, however, their identification with Computed Tomography in the hyperacute setting is challenging. We aimed to validate a clinical score to identify lacunar stroke in the acute setting, independently, with data from the WAKE-UP trial using magnetic resonance imaging.

METHODS

We analysed data from the WAKE-UP trial and extracted Oxfordshire Community Stroke Project (OCSP) classification. Lacunar score was defined by NIHSS<7 and OCSP lacunar syndrome. Assessment of lacunar infarct by two independent investigators was blinded to clinical data. We calculated sensitivity, specificity, negative and positive predictive value (NPV and PPV, respectively) of lacunar score.

RESULTS

We included 503 patients in the analysis, mean (±SD) age 65.2 (±11.6), 325 (65%) males, median (IQR) NIHSS=6 (4-9); 108 (22%) lacunar infarcts were identified on MR, patients fulfilling lacunar score criteria were 120 (24%), of which 47 (44%) had a lacunar infarct. Lacunar score correctly identified 322 (82%) of patients without lacunar infarct. Patients with lacunar score had lower NIHSS (4 vs 7,p<0.001), higher systolic (157 mmHg vs 151 mmHg,p=0.001) and diastolic (86 mmHg vs 83 mmHg,p=0.013) blood pressure and smaller infarct volume (2.4 ml vs 9.5 ml,p<0.001). Performance of lacunar score was: sensitivity 0.44; specificity 0.82; PPV 0.39; NPV 0.84; accuracy 0.73. Assuming a prevalence of lacunar stroke of 13%, PPV lowered to 0.30 but NPV was 0.90. Lacunar score performed better for supratentorial lacunar infarcts.

CONCLUSIONS

Lacunar score had a very good specificity and NPV for screening of lacunar stroke. Implementation of this simple tool into clinical practice may help hyperacute management and guide patient selection in clinical trials.

Myocardial injury in patients with acute ischemic stroke detected by cardiovascular magnetic resonance imaging

BACKGROUND

Patients with acute ischemic stroke (AIS) are at high risk of adverse cardiovascular events. Until now, the burden of myocardial injury derived from cardiovascular magnetic resonance imaging (CMR) has not been established in this population.

METHODS

Patients with AIS underwent CMR at 3 Tesla within 120 h after the index stroke as part of a prospective, single-center study. Patients with persistent atrial fibrillation were excluded. Morphology and function of both cardiac chambers and atria were assessed applying SSFP cine. Myocardial tissue differentiation was based on native and contrast-enhanced imaging including late gadolinium enhancement (LGE) after 0.15 mmol/kg gadobutrol for focal fibrosis and parametric T2- and T1-mapping for diffuse findings. To detect myocardial deformation global longitudinal (GLS), circumferential (GCS) and radial (GRS) strain was measured applying feature tracking. Cardiac troponin was measured using a high-sensitivity assay (99th percentile upper reference limit 14 ng/L). T2 mapping values were compared with 20 healthy volunteers.

RESULTS

CMR with contrast media was successfully performed in 92 of 115 patients (mean age 74 years, 40% female, known myocardial infarction 6%). Focal myocardial fibrosis (LGE) was detected in 31 of 92 patients (34%) of whom 23/31 (74%) showed an ischemic pattern. Patients with LGE were more likely to have diabetes, prior myocardial infarction, prior ischemic stroke, and to have elevated troponin levels compared to those without. Presence of LGE was accompanied by diffuse fibrosis (increased T1 native values) even in remote cardiac areas as well as reduced global radial, circumferential and longitudinal strain values. In 14/31 (45%) of all patients with LGE increased T2-mapping values were detectable.

CONCLUSIONS

More than one-third of patients with AIS have evidence of focal myocardial fibrosis on CMR. Nearly half of these changes may have acute or subacute onset. These findings are accompanied by diffuse myocardial changes and reduced myocardial deformation. Further studies, ideally with serial CMR measurements during follow-up, are required to establish the impact of these findings on long-term prognosis after AIS.

Polypharmacy, functional outcome and treatment effect of intravenous alteplase for acute ischaemic stroke

BACKGROUND AND PURPOSE

Polypharmacy is an important challenge in clinical practice. Our aim was to determine the effect of polypharmacy on functional outcome and treatment effect of alteplase in acute ischaemic stroke.

METHODS

This was a post hoc analysis of the randomized, placebo-controlled WAKE-UP trial of magnetic resonance imaging guided intravenous alteplase in unknown onset stroke. Polypharmacy was defined as an intake of five or more medications at baseline. Comorbidities were assessed by the Charlson Comorbidity Index (CCI). The primary efficacy variable was favourable outcome defined by a score of 0-1 on the modified Rankin Scale at 90 days. Logistic regression analysis was used to test for an association of polypharmacy with functional outcome, and for interaction of polypharmacy and the effect of thrombolysis.

RESULTS

Polypharmacy was present in 133/503 (26%) patients. Patients with polypharmacy were older (mean age 70 vs. 64 years; p < 0.0001) and had a higher score on the National Institutes of Health Stroke Scale at baseline (median 7 vs. 5; p = 0.0007). A comorbidity load defined by a CCI score ≥ 2 was more frequent in patients with polypharmacy (48% vs. 8%; p < 0.001). Polypharmacy was associated with lower odds of favourable outcome (adjusted odds ratio 0.50, 95% confidence interval 0.30-0.85; p = 0.0099), whilst the CCI score was not. Treatment with alteplase was associated with higher odds of favourable outcome in both groups, with no heterogeneity of treatment effect (test for interaction of treatment and polypharmacy, p = 0.29).

CONCLUSION

In stroke patients, polypharmacy is associated with worse functional outcome after intravenous thrombolysis independent of comorbidities. However, polypharmacy does not interact with the beneficial effect of alteplase.

Characteristics associated with outcome in patients with first-ever posterior fossa stroke

BACKGROUND AND PURPOSE

Factors such as infarct volume, infarct location and symptom severity can considerably influence long-term outcome in posterior fossa strokes. The decision about therapy can sometimes be complicated by discrepancies between infarct volume and clinical severity. We aimed to evaluate imaging and clinical parameters possibly influencing long-term outcome in patients with first-ever posterior fossa stroke.

METHODS

Imaging was performed on a 3-T magnetic resonance imaging scanner. Sixty-one of 1795 patients from the observational 1000Plus and LOBI studies (NCT00715533 and NCT02077582, clinicaltrials.org) were enrolled, meeting the inclusion criteria of first-ever posterior fossa stroke and magnetic resonance imaging examination within 24 h after symptom onset. Infarcts were classified as belonging to a proximal, middle or distal territory location in the posterior fossa. Good outcome was defined as a modified Rankin scale score of ≤1 at 3 months.

RESULTS

The largest lesion volumes on diffusion-weighted imaging on day 0 and fluid attenuation inversion recovery (FLAIR) on day 6 were found in the middle territory location with a median volume of 0.4 mL on diffusion-weighted imaging and 1.0 mL on FLAIR on day 6 versus 0.1/0.3 mL in the proximal and 0.1/0.1 mL in the distal territory location of the posterior fossa, respectively. Parameters associated with poor outcome were older age (P = 0.005), higher National Institutes of Health Stroke Scale score on admission/discharge (P = 0.016; P = 0.001), larger lesion volumes on FLAIR on day 6 (P = 0.013) and dysphagia (P = 0.02). There was no significant association between infarct location and modified Rankin scale score on day 90.

CONCLUSION

Infarct volume and clinical severity, but not infarct location, were the main contributors to poor long-term outcome in first-ever posterior fossa strokes.

Comparison of Gadoterate Meglumine and Gadobutrol in the MRI Diagnosis of Primary Brain Tumors: A Double-Blind Randomized Controlled Intraindividual Crossover Study (the REMIND Study)

BACKGROUND AND PURPOSE

Effective management of patients with brain tumors depends on accurate detection and characterization of lesions. This study aimed to demonstrate the noninferiority of gadoterate meglumine versus gadobutrol for overall visualization and characterization of primary brain tumors.

MATERIALS AND METHODS

This multicenter, double-blind, randomized, controlled intraindividual, crossover, noninferiority study included 279 patients. Both contrast agents (dose = 0.1 mmol/kg of body weight) were assessed with 2 identical MRIs at a time interval of 2-14 days. The primary end point was overall lesion visualization and characterization, scored independently by 3 off-site readers on a 4-point scale, ranging from "poor" to "excellent." Secondary end points were qualitative assessments (lesion border delineation, internal morphology, degree of contrast enhancement, diagnostic confidence), quantitative measurements (signal intensity), and safety (adverse events). All qualitative assessments were also performed on-site.

RESULTS

For all 3 readers, images of most patients (>90%) were scored good or excellent for overall lesion visualization and characterization with either contrast agent; and the noninferiority of gadoterate meglumine versus gadobutrol was statistically demonstrated. No significant differences were observed between the 2 contrast agents regarding qualitative end points despite quantitative mean lesion percentage enhancement being higher with gadobutrol (P < .001). Diagnostic confidence was high/excellent for all readers in >81% of the patients with both contrast agents. Similar percentages of patients with adverse events related to the contrast agents were observed with gadoterate meglumine (7.8%) and gadobutrol (7.3%), mainly injection site pain.

CONCLUSIONS

The noninferiority of gadoterate meglumine versus gadobutrol for overall visualization and characterization of primary brain tumors was demonstrated.

Right insular infarction and mortality after ischaemic stroke

BACKGROUND AND PURPOSE

Several studies have described an association between insular infarction and mortality. Large infarcts often include the insula and lesion size is associated with mortality. We hypothesized that there is an association between insular infarction and mortality independent of lesion volume.

METHODS

We included consecutive stroke patients between 1 September 2008 and 11 November 2012 from the 1000Plus database with an acute ischaemic lesion on diffusion-weighted imaging on day 1 and a completed 90-day follow-up. Insular infarct location was determined using the in-house software Stroke Lesion Atlas. In multiple Cox regression analysis (dependent variable: mortality), we adjusted for insular infarcts, age, lesion volume, history of atrial fibrillation, National Institutes of Health Stroke Scale and previous stroke.

RESULTS

We included 736 patients, of whom 168 had an insular infarction. Within a medium follow-up time of 107 days, cumulative survival was 90% in patients with insular infarction and 99% in patients without insular infarction (P < 0.001). Right insular infarction was independently associated with mortality (hazard ratio, 2.60; confidence interval, 1.3-5.4; P = 0.010).

CONCLUSIONS

In our study, right insular involvement was a prognostic marker for mortality after ischaemic stroke. A selection bias towards patients able to give informed consent warrants further studies.

Hyperintense Vessels on FLAIR: Hemodynamic Correlates and Response to Thrombolysis

BACKGROUND AND PURPOSE

Hyperintense vessels on baseline FLAIR MR imaging of patients with ischemic stroke have been linked to leptomeningeal collateralization, yet the ability of these to maintain viable ischemic tissue remains unclear. We investigated whether hyperintense vessels on FLAIR are associated with the severity of hypoperfusion and response to thrombolysis in patients treated with intravenous tissue-plasminogen activator.

MATERIALS AND METHODS

Consecutive patients with ischemic stroke with an MR imaging before and within 24 hours of treatment, with proved vessel occlusion and available time-to-maximum maps were included (n = 62). The severity of hypoperfusion was characterized on the basis of the hypoperfusion intensity ratio (volume with severe/mild hypoperfusion [time-to-maximum ≥ 8 seconds / time-to-maximum ≥ 2 seconds]). The hypoperfusion intensity ratio was dichotomized at the median to differentiate moderate (hypoperfusion intensity ratio ≤ 0.447) and severe (hypoperfusion intensity ratio > 0.447) hypoperfusion. Good outcome was defined as a modified Rankin Scale score of ≤2.

RESULTS

Hyperintense vessels on FLAIR were identified in 54 patients (87%). Patients with extensive hyperintense vessels on FLAIR (>4 sections) had higher NIHSS scores, larger baseline lesion volumes, higher rates of perfusion-diffusion mismatch, and more severe hypoperfusion (hypoperfusion intensity ratio). In stepwise backward multivariate regression analysis for the dichotomized hypoperfusion intensity ratio (including stroke etiology, age, perfusion deficit, baseline lesion volume, smoking, and extent of hyperintense vessels on FLAIR), extensive hyperintense vessels on FLAIR were independently associated with severe hypoperfusion (OR, 6.8; 95% CI, 1.1-42.7; P = .04). The hypoperfusion intensity ratio was an independent predictor of a worse functional outcome at 3 months poststroke (OR, 0.2; 95% CI, 0.5-0.6; P < .01).

CONCLUSIONS

Hyperintense vessels on FLAIR are associated with larger perfusion deficits, larger infarct growth, and more severe hypoperfusion, suggesting that hyperintense vessels on FLAIR most likely indicate severe ischemia as a result of insufficient collateralization.

The Cortical Signature of Central Poststroke Pain: Gray Matter Decreases in Somatosensory, Insular, and Prefrontal Cortices

It has been proposed that cortical structural plasticity plays a crucial role in the emergence and maintenance of chronic pain. Various distinct pain syndromes have accordingly been linked to specific patterns of decreases in regional gray matter volume (GMV). However, it is not known whether central poststroke pain (CPSP) is also associated with cortical structural plasticity. To determine this, we employed T1-weighted magnetic resonance imaging at 3 T and voxel-based morphometry in 45 patients suffering from chronic subcortical sensory stroke with (n = 23) and without CPSP (n = 22), and healthy matched controls (n = 31). CPSP patients showed decreases in GMV in comparison to healthy controls, involving secondary somatosensory cortex (S2), anterior as well as posterior insular cortex, ventrolateral prefrontal and orbitofrontal cortex, temporal cortex, and nucleus accumbens. Comparing CPSP patients to nonpain patients revealed a similar but more restricted pattern of atrophy comprising S2, ventrolateral prefrontal and temporal cortex. Additionally, GMV in the ventromedial prefrontal cortex negatively correlated to pain intensity ratings. This shows for the first time that CPSP is accompanied by a unique pattern of widespread structural plasticity, which involves the sensory-discriminative areas of insular/somatosensory cortex, but also expands into prefrontal cortex and ventral striatum, where emotional aspects of pain are processed.

MR imaging features of amyloid-related imaging abnormalities

BACKGROUND AND PURPOSE

AD is one of the few leading causes of death without a disease-modifying drug; however, hopeful agents are in various phases of development. MR imaging abnormalities, collectively referred to as amyloid-related imaging abnormalities, have been reported for several agents that target cerebral Aβ burden. ARIA includes ARIA-E, parenchymal or sulcal hyperintensities on FLAIR indicative of parenchymal edema or sulcal effusions, and ARIA-H, hypointense regions on gradient recalled-echo/T2* indicative of hemosiderin deposition. This report describes imaging characteristics of ARIA-E and ARIA-H identified during studies of bapineuzumab, a humanized monoclonal antibody against Aβ.

MATERIALS AND METHODS

Two neuroradiologists with knowledge of imaging changes reflective of ARIA reviewed MR imaging scans from 210 bapineuzumab-treated patients derived from 3 phase 2 studies. Each central reader interpreted the studies independently, and discrepancies were resolved by consensus. The inter-reader κ was 0.76, with 94% agreement between neuroradiologists regarding the presence or absence of ARIA-E in individual patients.

RESULTS

Thirty-six patients were identified with incident ARIA-E (17.1%, 36/210) and 26 with incident ARIA-H (12.4%, 26/210); of those with incident ARIA-H, 24 had incident microhemorrhages and 2 had incident large superficial hemosiderin deposits.

CONCLUSIONS

In 49% of cases of ARIA-E, there was the associated appearance of ARIA-H. In treated patients without ARIA-E, the risk for incident blood products was 4%. This association between ARIA-E and ARIA-H may suggest a common pathophysiologic mechanism. Familiarity with ARIA should permit radiologists and clinicians to recognize and communicate ARIA findings more reliably for optimal patient management.

[EU-funded treatment study: WAKE-UP: a randomized, placebo-controlled MRI-based trial of thrombolysis in wake-up stroke]

Patients waking up with stroke symptoms are generally excluded from intravenous thrombolysis. It was shown that magnetic resonance imaging (MRI) can identify patients within the time window for thrombolysis (≤  4.5 h from symptom onset) by a mismatch between the acute ischemic lesion visible on diffusion-weighted imaging (DWI) but not visible on fluid-attenuated inversion recovery (FLAIR) imaging. The WAKE-UP trial is an investigator initiated, European, randomized, double-blind, placebo-controlled trial designed to test efficacy and safety of MRI-based thrombolysis with alteplase (tPA) in stroke patients with unknown time of symptom onset, e.g. due to symptom recognition on awakening. A total of 800 patients showing MRI findings of a DWI-FLAIR-mismatch will be randomized to either tPA or placebo. The primary efficacy endpoint will be favourable outcome defined by a modified Rankin scale score 0-1 at day 90. The primary safety outcome measures will be mortality and death or dependency defined by modified Rankin scale score 4-6 at 90 days. If positive the WAKE-UP trial is expected to change clinical practice and to make effective and safe treatment available for a large group of acute stroke patients currently excluded from specific acute treatment.

[Mobile CT: technical aspects of prehospital stroke imaging before intravenous thrombolysis]

PURPOSE

To reduce the time from symptom onset to treatment with tissue plasminogen activator (tPA) in ischemic stroke, an ambulance was equipped with a CT scanner. We analyzed process and image quality of CT scanning during the pilot study regarding image quality and safety issues.

MATERIALS AND METHODS

The pilot study of a stroke emergency mobile unit (STEMO) ran over a period of 12 weeks on 5 weekdays from 7a.m. to 6:30 p.m. A teleradiological service for the justifying indication and reporting was established. The radiographer was responsible for the performance of the CT scan on the ambulance. 64 cranial CT scans and 1 intracranial CT angiography were performed. We compared times from ambulance alarm to treatment decision (time of last brain scan) with a cohort of 50 consecutive tPA treatments before implementation of STEMO.

RESULTS

62 (95%) of the 65 scans performed had sufficient quality for reading. Technical quality was not optimal in 45 cases (69%) mainly caused by suboptimal positioning of patient or eye lens protection. Motion artefacts were observed in 8 exams (12%). No safety issues occurred for team or patients. 23 patients were treated with thrombolysis. Time from alarm to last CT scan was 18 minutes shorter than in the tPA cohort before STEMO implementation.

CONCLUSION

A teleradiological support for primary stroke imaging by CT on-site is feasible, quality-wise of diagnostic value and has not raised safety issues.

FLAIR vascular hyperintensities in acute ICA and MCA infarction: a marker for mismatch and stroke severity?

BACKGROUND

Vascular hyperintensities of brain-supplying arteries on stroke FLAIR MRI are common and represent slow flow or stasis. FLAIR vascular hyperintensities (FVH) are discussed as an independent marker for cerebral hypoperfusion, but the impact on infarct size and clinical outcome in acute stroke patients is controversial. This study evaluates the association of FVH with infarct morphology, clinical stroke severity and infarct growth in patients with symptomatic internal carotid artery (ICA) or middle cerebral artery (MCA) occlusion.

METHODS

MR images of 84 patients [median age 73 years (IQR 65-80), 56.0% male, median NIHSS 7 (IQR 3-13)] with acute stroke due to symptomatic ICA or MCA occlusion or stenosis were reviewed. Vessel occlusions were identified by MRA time of flight and graded with the TIMI score. Diffusion and perfusion deficit volumes on admission and FLAIR lesion volumes on discharge were assessed. The presence and number of FVH were evaluated according to MCA-ASPECT areas, and associations with MR volumes, morphology of infarction, recanalization status, presence of white matter disease and hemorrhagical transformation as well as with stroke severity (NIHSS), stroke etiology and thrombolysis rate were analyzed.

RESULTS

FVH were detectable in 75 (89.3%) patients. The median number of FVH was 4 (IQR 2-7). Patients with FVH >4 presented with more severe strokes due to NIHSS (p = 0.021), had larger initial DWI lesions (p = 0.008), perfusion deficits (p = 0.001) and mismatch volumes/ratios (p = 0.005). The final infarct volume was larger (p = 0.005), and hemorrhagic transformation was more frequent (p = 0.029) in these patients.

CONCLUSIONS

The presence of FVH indicates larger ischemic areas in brain parenchyma predominantly caused by proximal anterior circulation vessel occlusion. A high count of FVH might be a further surrogate marker for initial ischemic mismatch and stroke severity.

MRI-based intravenous thrombolysis in stroke patients with unknown time of symptom onset

BACKGROUND

Currently, stroke patients with unknown time of symptom onset (UTOS) are excluded from therapy with intravenous tissue Plasminogen Activator. We hypothesized that MRI-based intravenous thrombolysis is safe in UTOS.

METHODS

We analyzed radiological and clinical data as well as outcomes of stroke patients (including UTOS) who received intravenous thrombolytic therapy after MRI.

RESULTS

Compared to patients with known time of symptom onset (n=131), UTOS (n=17) were older (81, 71-88 vs. 75 years, 66-82, P=0.03), had a longer median time between last-seen-well and thrombolysis (12.3 h, IQR 11.5-15.2 h vs. 2.1 h, 1.8-2.8 h, P<0.01), had a longer median door-to-needle time (86 min, 49-112 vs. 60 min, 49-76, P=0.02), and a higher rate of arterial obstruction on MR-angiography (82.4% vs. 56.5%, P=0.04). No symptomatic intracerebral hemorrhage occurred in UTOS. After 3 months, there was no significant difference between groups concerning good functional outcome (modified Rankin Scale 0-2; 35.3% vs. 49.6%, P=0.26) or mortality (0% vs. 15.3%, P=0.08). In multivariate analyses including age, gender, baseline NIHSS, and atrial fibrillation UTOS did not have an independent effect on good functional outcome after 3 months (OR 1.16; 0.32-4.12, P=0.81).

CONCLUSIONS

Thrombolysis after MRI seems safe and effective in UTOS. This observation may encourage those who plan prospective placebo-controlled trials of thrombolytics in this subgroup of stroke patients.

Myocardial scars are an underestimated cardiovascular burden in patients with internal carotid artery stenosis

BACKGROUND

Patients with internal carotid artery (ICA) stenosis have an increased incidence of coronary heart disease. Evidence about the incidence of clinically silent myocardial infarction (MI) in these patients is limited. Contrast-enhanced cardiac magnetic resonance (CMR) imaging allows for the detection of minor myocardial damage.

OBJECTIVE

We tested whether patients with ICA stenosis exhibit a relevant incidence of silent MI when assessed by CMR.

METHODS

In a single-center study, 77 consecutive patients (age 68 +/- 7 years) with suspected ICA stenosis were imaged prospectively with a combined MRI protocol including T(1), T(2), diffusion-weighted imaging, fluid-attenuated inversion recovery, and contrast-enhanced MR angiography (CEMRA) imaging of the brain and a short (11 min) CMR protocol with left ventricular function and late gadolinium enhancement imaging. Blinded to any clinical information, two readers evaluated the cardiac and neuroradiologic examinations.

RESULTS

Of 154 imaged ICA, 85 presented with stenosis and 17 were occluded. In 7 patients, the suspected ICA stenosis could not be confirmed by CEMRA. In the remaining 70 patients with ICA stenosis, 34.3% had cerebral lesions (15.7% with a homodynamic pattern,18.6% with territorial infarction). CMR detected MI in 29 (41%) patients, whereas ECG and medical history enabled diagnosis in only 7 (10%) patients.

CONCLUSIONS

ICA stenosis patients have a higher incidence of myocardial scars proving silent MI when detected by contrast-enhanced CMR than clinically expected. Whether the presence and extent of silent MIs detected by CMR affect peri-interventional risk and prognosis of ICA stenosis patients remains to be evaluated in a large patient cohort with long-term follow-up.

[Diffusion and perfusion MR imaging in stroke]

Magnetic resonance imaging (MRI) in stroke makes it possible to visualize the initial infarct in cases of acute cerebral ischemia. Perfusion MRI serves to determine which tissues are additionally at risk of infarction due to persistent hypoperfusion. MRI also allows those examiners with limited experience to reliably confirm an infarct. The most important differential diagnosis of cerebral ischemia, intracerebral hemorrhage, can likewise be recognized with certainty using MRI. Although diffusion and perfusion MRI only demonstrate the pathophysiology of cerebral ischemia approximately, the method is suited for identifying those patients who would profit from reperfusion therapy. Whether MRI is also appropriate as an aid to reaching a prognosis on the risk of secondary hemorrhage has not yet been resolved.

[Acute cerebral circulation problems]

Acute stroke is the third most common cause of death and also the most common cause of permanent disability in industrialized countries. Ischemic stroke is caused by occlusion of a cerebral artery leading to a critical reduction in brain perfusion in the respective brain area (penumbra). Most acute stroke treatment strategies are based on the penumbra concept: attaining rapid and persistent reperfusion is followed by the protection of critically ischemic and not yet infarcted (penumbral) tissue by, e.g., neuroprotection. Examination of the acute stroke patient includes a brief history, neurostatus and imaging (CT or MRI) for the exclusion of intracerebral hemorrhage. The diagnostic standard is CT; modern stroke MRI protocols provide an improved selection in later time windows. Intravenous thrombolysis with rt-PA within 3 h of symptom onset is the only approved therapy with a proven significant benefit for the patient. The effect is smaller but still significant if treatment occurs up to 4.5 h, and may still be present in MRI selected patients up to 9 h. More aggressive forms of therapy include interventional reperfusion techniques and therapy of malignant MCA infarction such as hemicraniectomy and hypothermia, which at present, however, are not routine and are only performed in specialized centers.

Cerebrovascular manifestations of Takayasu arteritis in Europe

OBJECTIVES

Takayasu arteritis is well known as a cause of stroke in Asia but has rarely been described in the Western world. Here we report the clinical and neuroimaging follow-up of a series of patients with Takayasu arteritis from Europe.

METHODS

Seventeen consecutive patients who fulfilled the diagnostic criteria for Takayasu arteritis of the American College of Rheumatology were evaluated on follow-up by standardized neurological examination, sonography and MRI.

RESULTS

At follow-up almost 20 yr after onset of symptoms, the subclavian artery and the common carotid artery were often affected. In addition, evidence of intracranial pathology was found in seven patients. In contrast to the severe vessel involvement, the neurological state was stable. Two patients had suffered from stroke before the diagnosis was made and therapy was initiated, and one patient had recurrent transient ischaemic attacks. Intermittent dizziness was associated with pathology of the vertebral and basilar arteries. However, clinical symptoms of subclavian steal syndrome were rare.

CONCLUSION

This case series shows that the clinical neurological course of Takayasu arteritis on treatment is benign in most cases despite the severe vascular involvement.

Stellenwert moderner CT-Techniken bei der Diagnostik des akuten Schlaganfalls

BACKGROUND

Thrombolysis is the treatment of choice for acute stroke within 3 h after symptom onset. Treatment beyond the 3 h time window has not been shown to be effective in any single trial, however, metaanalyses suggest a somewhat less but still significant effect within 3 to 6 h after stroke. It seems reasonable to apply improved selection criteria that allow to differentiate the patients with a relevant indication for thrombolytic therapy from those who have not. While stroke MRI seems to be the upcoming standard, due to its low availability the need for an improved CT-based patient selection is evident.

METHODS

The present literature on imaging in stroke has been thoroughly reviewed. The diagnostic strengths and weaknesses of conventional CT, CT angiography (CTA), CTA source image analysis (CTA-SI) and perfusion CT (PCT) for an acute diagnostic stroke workup are critically reviewed in this article. The authors present their view about a comprehensive diagnostic approach to acute stroke in accordance to stroke MRI findings, which allows to challenge the rigid therapeutic time window and improve patient management.

CONCLUSION

Information about the presence or absence of ICH by non contrast CT and vessel occlusion by means of CTA is deemed obligatory before rt-PA is given in the 3-6 hour time window. Clear demarcation of an early hypodensity exceeding 1/3 of the MCA territory on NCCT or CTA-SI should preclude thrombolytic therapy. The irreversibly damaged infarct core and the ischemic but still viable thus salvageable tissue at risk of infarction as seen on CT/CTA/CTA-SI/PCT should be obtained before thrombolysis is initiated within 3-6 hours. Once these advanced techniques are used, the therapeutic time window can be extended with acceptable safety. However, comprehensive informed consent is mandatory, especially when thrombolytic therapy is considered beyond established time windows.

MRI in acute subarachnoid haemorrhage; findings with a standardised stroke protocol

There is doubt as to whether acute haemorrhage is visible on MRI. We carried out MRI within 6 h of symptom onset on five patients with minor (low Hunt and Hess grades 1 or 2) subarachnoid haemorrhage (SAH) diagnosed by CT to search for any specific pattern. We used our standard stroke MRI protocol, including multiecho proton density (PD)- and T2-weighted images, echoplanar (EPI) diffusion- (DWI) and perfusion- (PWI) weighted imaging, and MRA. In all cases SAH was clearly visible on PD-weighted images with a short TE. In four patients it caused a low-signal rim on the T2*-weighted source images of PWI, and DWI revealed high signal in SAH. In the fifth patient SAH was perimesencephalic; susceptibility effects from the skull base made it impossible to detect SAH on EPI DWI and T2*-weighted images. Perfusion maps were normal in all cases. MRA and conventional angiography revealed an aneurysm in only one patient. Stroke MRI within 6 h of SAH thus shows a characteristic pattern.

Effect of incomplete (spontaneous and postthrombolytic) recanalization after middle cerebral artery occlusion: a magnetic resonance imaging study

BACKGROUND AND PURPOSE

Early reperfusion is one of the best predictors of good outcome after acute middle cerebral artery (MCA) occlusion. The purpose of this study was to analyze the frequency and relevance of incomplete recanalization for tissue and clinical outcome.

METHODS

From a larger acute stroke database (Kompetenznetzwerk Schlaganfall B5), all patients (n=82) with MCA main stem occlusion (excluding carotid T-occlusions) were selected. These patients had received a multiparametric stroke MRI protocol including diffusion- and perfusion-weighted imaging (DWI, PWI) and MR angiography (MRA) within 6 hours after symptom onset, at day 1 and after 1 week. Recanalization status was determined with MRA on day 1 (according to Thrombolysis In Myocardial Infarction flow grades) and used to group patients into those with persistent occlusion (0) or minimal (1), partial (2), or complete (3) recanalization.

RESULTS

Incomplete recanalization according to MRI criteria was found in 39 patients (grade 1: n=20; grade 2: n=19), complete recanalization in 10, and persistent occlusion in 33. There was no statistically significant difference in any of the clinical (National Institutes of Health Stroke Scale score) or MRI baseline parameters (DWI lesion, PWI deficit, mismatch volume, mismatch ratio). However, lesion growth was smaller in patients with recanalization (even in patients with only minimal recanalization) and outcome was related to the degree of recanalization (mean modified Rankin score at 90 days: 3.36, 2.70, 1.79, and 1.44 for the groups with no, minimal, partial, and complete recanalization, respectively). Both incomplete and complete recanalization was more frequent in patients receiving thrombolysis.

CONCLUSIONS

Incomplete recanalization on day 1 is a frequent MR finding after MCA main stem occlusion, indicating a more favorable clinical course than persistent occlusion. MR indicators of early recanalization could be useful surrogates of efficacy in thrombolytic trials.

[Modern magnetic resonance techniques in stroke]

In industrialized nations, stroke is the most common cause of permanent disability and need of care. Causal treatment is possible only during the first few hours following the stroke, in the form of systemic fibrinolysis. An exact diagnosis of the causative pathology must be made before starting the therapy, and this must happen in the shortest possible period of time. Using imaging techniques, the whole spectrum of differential diagnoses of cerebral ischemia must be covered, including above all intracerebral and subarachnoid hemorrhage. Although computed tomography (CT) is excellently suited for determining hemorrhage, infarct can be recognized with much better contrast using diffusion-weighted magnetic resonance (MR) imaging (DWI). Stroke MR imaging additionally allows the representation of vital "tissue at risk"of infarction using perfusion images as well as the recognition of vessel occlusion using MR angiography. This paper is intended to define the usefulness of DWI in comparison to CT techniques and to elucidate the use of diffusion coefficients for differentiating the various stages of infarction. Besides presenting an explanation of the basic principles of modern stroke MR imaging, typical results of MR perfusion measurements and the appearance of hemorrhages on MR will be explained.

Effect of intravenous thrombolysis on MRI parameters and functional outcome in acute stroke <6 hours

BACKGROUND AND PURPOSE

The goals of this study were to examine MRI baseline characteristics of patients with acute ischemic stroke (AIS) and to study the influence of intravenous tissue plasminogen activator (tPA) on MR parameters and functional outcome using a multicenter approach.

METHODS

In this open-label, nonrandomized study of AIS patients with suspected anterior circulation stroke, subjects received a multiparametric stroke MRI protocol (diffusion- and perfusion-weighted imaging and MR angiography) within 6 hours after symptom onset and on follow-up. Patients were treated either with tPA (thrombolysis group) or conservatively (no thrombolysis group). Functional outcome was assessed on day 90 (modified Rankin Score; mRS).

RESULTS

We enrolled 139 AIS patients (no thrombolysis group, n=63; thrombolysis group, n=76). Patients treated with tPA were more severely affected (National Institutes of Health Stroke Scale score, 10 versus 13; P=0.002). Recanalization rates were higher in the thrombolysis group (Thrombolysis in Myocardial Infarction criteria 1 through 3 on day 1; 66.2% versus 32.7%; P<0.001). Proximal vessel occlusions resulted in larger infarct volumes and worse outcome (P=0.02). Thrombolysis was associated with a better outcome regardless of the time point of tPA treatment (< or =3 hours or 3 to 6 hours) (univariate analysis: mRS < or =2, P=0.017; mRS < or =1, P=0.023). Age (P=0.003), thrombolytic therapy at 0 to 6 hours (P=0.01), recanalization (P=0.016), lesion volume on day 7 (P=0.001), and initial National Institutes of Health Stroke Scale score (P=0.001) affected functional outcome (mRS on day 90) positively (multivariate analysis). The time point of tPA therapy affected the recanalization rate (P=0.024) but not final infarct volume.

CONCLUSIONS

In this pilot study, tPA therapy had a beneficial effect on vessel recanalization and functional outcome. Multiparametric MRI delineates tissue at risk of infarction in AIS patients, which may be helpful for the selection of patients for tPA therapy. tPA therapy appeared safe and effective beyond a 3-hour time window. This study delivers the rationale for a randomized, MR-based tPA trial.

CT and diffusion-weighted MR imaging in randomized order: diffusion-weighted imaging results in higher accuracy and lower interrater variability in the diagnosis of hyperacute ischemic stroke

BACKGROUND AND PURPOSE

Diffusion-weighted MRI (DWI) has become a commonly used imaging modality in stroke centers. The value of this method as a routine procedure is still being discussed. In previous studies, CT was always performed before DWI. Therefore, infarct progression could be a reason for the better result in DWI.

METHODS

All hyperacute (<6 hours) stroke patients admitted to our emergency department with a National Institutes of Health Stroke Scale (NIHSS) score >3 were prospectively randomized for the order in which CT and MRI were performed. Five stroke experts and 4 residents blinded to clinical data judged stroke signs and lesion size on the images. To determine the interrater variability, we calculated kappa values for both rating groups.

RESULTS

A total of 50 patients with ischemic stroke and 4 patients with transient symptoms of acute stroke (median NIHSS score, 11; range, 3 to 27) were analyzed. Of the 50 patients, 55% were examined with DWI first. The mean delay from symptom onset until CT was 180 minutes; that from symptom onset until DWI was 189 minutes. The mean delay between DWI and CT was 30 minutes. The sensitivity of infarct detection by the experts was significantly better when based on DWI (CT/DWI, 61/91%). Accuracy was 91% when based on DWI (CT, 61%). Interrater variability of lesion detection was also significantly better for DWI (CT/DWI, kappa=0.51/0.84). The assessment of lesion extent was less homogeneous on CT (CT/DWI, kappa=0.38/0.62). The differences between the 2 modalities were stronger in the residents' ratings (CT/DWI: sensitivity, 46/81%; kappa=0.38/0.76).

CONCLUSIONS

CT and DWI performed with the same delay after onset of ischemic stroke resulted in significant differences in diagnostic accuracy. DWI gives good interrater homogeneity and has a substantially better sensitivity and accuracy than CT even if the raters have limited experience.

Serial analysis of the apparent diffusion coefficient time course in human stroke

Acute cerebral ischemic injury can be rapidly detected on diffusion-weighted images. The apparent diffusion coefficient (ADC) depends on the stage of cytotoxic edema and water content in the infarcted parenchyma. The purpose of this study is to determine the time course of ADC during the first days of ischemic stroke. These data should make it possible to distinguish between multiple stroke and a single progressive infarction. Eight patients with clinically diagnosed acute cerebral ischemia were examined by diffusion-weighted MRI from 2 to 20 h after onset of symptoms. Daily control scans were performed for up to 10 days. ADC values were analyzed from 55 MRI studies. Furthermore, ADC was measured in the tissue which showed a hyperintense signal at the first examination and in the contralateral tissue. White and gray matter were analyzed separately. Data were expressed as the ratio ADC (rADC) of lesion to control region of interest. All patients showed a uniform reduction in rADC from the first hours of stroke and decreasing to the 3rd day. The rADC increased again from the 4th day up to the point of pseudo-normalization on day 9. The gray matter showed a slightly faster increase than the white matter. rADC shows significant changes in the first days after stroke, following a rather uniform time course. Together with T2-weighted MRI this makes it possible to differentiate between hyperacute, acute, and chronic stroke. Furthermore, the age of an ischemia can be determined and multiple strokes can be distinguished from a single progressive stroke.

[Modern nuclear magnetic resonance techniques in stroke]

In industrialized nations, stroke is the most common cause of permanent disability and need of care. Causal treatment is possible only during the first few hours following the stroke, in the form of systemic fibrinolysis. An exact diagnosis of the causative pathology must be made before starting the therapy, and this must happen in the shortest possible period of time. Using imaging techniques, the whole spectrum of differential diagnoses of cerebral ischemia must be covered, including above all intracerebral and subarachnoid hemorrhage. Although computed tomography (CT) is excellently suited for determining hemorrhage, infarct can be recognized with much better contrast using diffusion-weighted magnetic resonance (MR) imaging (DWI). Stroke MR imaging additionally allows the representation of vital "tissue at risk" of infarction using perfusion images as well as the recognition of vessel occlusion using MR angiography. This paper is intended to define the usefulness of DWI in comparison to CT techniques and to elucidate the use of diffusion coefficients for differentiating the various stages of infarction. Besides presenting an explanation of the basic principles of modern stroke MR imaging, typical results of MR perfusion measurements and the appearance of hemorrhages on MR will be explained.

Thrombolytic therapy for ischemic stroke--a review. Part II--Intra-arterial thrombolysis, vertebrobasilar stroke, phase IV trials, and stroke imaging

OBJECTIVE

Intra-arterial thrombolytic therapy for carotid and vertebrobasilar stroke may result in a more rapid clot lysis and higher recanalization rates than can be achieved with intravenous thrombolysis and thus may warrant the more invasive and time-consuming therapeutic approach. We present an overview of all hitherto completed trials of intra-arterial thrombolytic therapy for carotid and vertebrobasilar artery stroke including recommendations for therapy and a meta-analysis. Furthermore, new imaging techniques such as diffusion- and perfusion-weighted magnetic resonance imaging and their impact on patient selection are discussed. Finally, phase IV trials of thrombolysis in general and cost efficacy analyses are presented.

DATA SOURCES

We performed an extensive literature search not only to identify the larger and well-known randomized trials but also to identify smaller pilot studies and case series. Trials included in this review, among others, are the PROACT I and PROACT II studies and the Cochrane Library report.

CONCLUSION

Intra-arterial thrombolytic therapy of acute M1 and M2 occlusions with 9 mg/2 hrs pro-urokinase significantly improves outcome if administered within 6 hrs after stroke onset. Seven patients need to be treated to prevent one patient from death or dependence. Vertebrobasilar occlusion has a grim prognosis and intra-arterial thrombolytic therapy to date is the only life-saving therapy that has demonstrated benefit with regard to mortality and outcome, albeit not in a randomized trial. New magnetic resonance imaging techniques may facilitate and improve the selection of patients for thrombolytic therapy. Presently, thrombolytic therapy is still underutilized because of problems with clinical and time criteria, and lack of public and professional education to regard stroke as a treatable emergency. If applied more widely, thrombolytic therapy may result in profound cost savings in health care and reduction of long-term disability of stroke patients.

Thrombolytic therapy for ischemic stroke--a review. Part I--Intravenous thrombolysis

OBJECTIVE

Thrombolytic therapy for acute ischemic stroke was implemented into clinical routine 4 yrs ago. Unfortunately, at present <2% of eligible patients receive thrombolytic therapy. We present an overview of all hitherto completed trials of intravenous thrombolytic therapy for carotid artery stroke including recommendations for therapy and diagnostic procedures and their impact on patient selection and meta-analyses.

DATA SOURCES

We performed an extensive literature search not only to identify the larger and well-known randomized trials but also to identify smaller pilot studies and case series. Trials included in this review, among others, are the National Institute of Neurologic Disorders and Stroke (NINDS) study, European Cooperative Acute Stroke Study I and II, and Alteplase Thrombolysis for Acute Noninterventional Therapy in Ischemic Stroke (ATLANTIS) A and B and two large meta-analyses, including the Cochrane Library report.

CONCLUSION

Intravenous thrombolytic therapy with recombinant tissue plasminogen activator has demonstrated a significant benefit and has proven to be safe for patients who can be treated within 3-6 hrs after symptom onset. This benefit is at the cost of an increased rate of symptomatic intracranial hemorrhage without a significant effect on overall mortality. In general, the benefit of thrombolysis decreases and the risks increase with progressing time after symptom onset. Presently, thrombolytic therapy is still underutilized because of problems with clinical and time criteria, and lack of public and professional education to regard stroke as a treatable emergency. If applied more widely, thrombolytic therapy may result in profound cost savings in health care and reduction of long-term disability of stroke patients.

Stroke magnetic resonance imaging within 6 hours after onset of hyperacute cerebral ischemia

We studied the diagnostic and prognostic value of diffusion- and perfusion-weighted magnetic resonancce imaging (DWI and PWI) for the initial evaluation and follow-up monitoring of patients with stroke that had ensued less than 6 hours previously. Further, we examined the role of vessel patency or occlusion and subsequent recanalization or persistent occlusion for further clinical and morphological stroke progression so as to define categories of patients and facilitate treatment decisions. Fifty-one patients underwent stroke magnetic resonance imaging (DWI, PWI, magnetic resonance angiography, and T2-weighted imaging) within 3.3 +/- 1.29 hours, and, of those, 41 underwent follow-up magnetic resonance imaging on day 2 and 28 on day 5. In addition, we assessed clinical scores (on the National Institutes of Health Stroke Scale, Scandinavian Stroke Scale, Barthel Index, and Modified Rankin Scale) on days 1, 2, 5, 30, and 90 and performed volumetric analysis of lesion volumes. In all, 25 patients had a proximal, 18 a distal, and 8 no vessel occlusion. Furthermore, 15 of 43 patients exhibited recanalization on day 2. Vessel occlusion was associated with a PWI-DWI mismatch on the initial magnetic resonance imaging, vessel patency with a PWI-DWI match (p < 0.0001). Outcome scores and lesion volumes differed significantly between patients experiencing recanalization and those who did not (all p < 0.0001). Acute DWI and PWI lesion volumes correlated poorly with acute clinical scores and only modestly with outcome scores. We have concluded on the basis of this study that early recanalization saves tissue at risk of ischemic infarction and results in significantly smaller infarcts and a significantly better clinical outcome. Patients with proximal vessel occlusions have a larger amount of tissue at risk, a lower recanalization rate, and a worse outcome. Urgent recanalization seems to be of utmost importance for these patients.

Masking of vertebral artery dissection by severe trauma to the cervical spine

STUDY DESIGN

A prospective case study was performed.

OBJECTIVES

To illustrate the association of cervical trauma with vertebral artery dissection, and to propose a diagnostic and therapeutic algorithm for suspected traumatic vertebral artery dissection.

SUMMARY OF BACKGROUND DATA

Vertebral artery dissection is a recognized but underdiagnosed complication of trauma to the cervical spine. Symptoms of spinal cord injury, however, may obscure those of vertebral artery dissection, presumably causing gross underdiagnosis of this complication.

METHODS

All patients with vertebral artery dissection admitted to the authors' facility between 1992 and 1997 were screened for cervical trauma.

RESULTS

This article presents four patients with severe trauma to the cervical spine, defined as luxation, subluxation, or fracture, in whom symptoms of vertebral artery dissection developed after a delay ranging from several hours to weeks. The traumatic vertebral artery dissection typically was located at the site of vertebral injury or cranial to it. One patient with fracture of the odontoid process survived symptom free without ischemic brain infarctions. Another patient survived with traumatic quadriplegia in addition to large cerebellar and posterior cerebral artery infarctions. Two patients died as a result of fulminant vertebrobasilar infarctions, both with only moderate impairment from the primary spinal cord injury.

CONCLUSIONS

Early signs of vertebral artery dissection include head and neck pain, often localized to the site of intimal disruption, which may be disguised by the signs of the spinal injury. Early Doppler ultrasound and duplex sonography as a noninvasive screening method should be performed for patients with severe trauma to the cervical spine. In cases of vertebral artery dissection, immediate anticoagulation should be initiated. Traumatologists should be aware of this complication in evaluating patients with severe trauma of the cervical spine, and also for a variety of forensic reasons.

Feasibility and practicality of MR imaging of stroke in the management of hyperacute cerebral ischemia

BACKGROUND AND PURPOSE

Neuroimaging techniques such as diffusion- and perfusion-weighted MR imaging have been proposed as tools for advanced diagnosis in hyperacute ischemic stroke. There is, however, substantial doubt regarding the feasibility and practicality of applying MR imaging for the diagnosis of stroke on a routine basis, especially with respect to possible delay for specific treatment such as thrombolysis. In this study, we tested whether MR imaging of stroke is safe, fast, and accurate, and whether the gain in additional information can be used in the daily routine without a loss of time and a risk of suboptimal treatment for the patient with stroke.

METHODS

Between September 1997 and August 1999, 64 patients with acute ischemic stroke were recruited for MR imaging (ie, diffusion-weighted imaging, perfusion-weighted imaging, MR angiography, T2-weighted imaging) after a baseline CT was performed. We evaluated practicality and feasibility of MR imaging of stroke by analyzing the intervals between symptom onset, arrival, CT, and MR imaging.

RESULTS

Sixty-four patients (mean age, 60.9 years) underwent routine CT and MR imaging within 12 hours after stroke onset (n=25, < or =3 hr; n=26, 3-6 hr; n=13, 6-12 hr). Median times to arrival, start of CT, MR imaging, and between CT and MR imaging were 1.625 hours, 2 hours, 3.875 hours, and 1 hour, respectively. Intervals between symptom onset and MR imaging (P<.005), arrival and MR imaging (P<.002), and CT and MR imaging (P=.0007) differed significantly between the early phase of the study and after November 1998, whereas the intervals between symptom onset and arrival, symptom onset and CT, and arrival and CT did not. Hemorrhage could be excluded in all; a perfusion/diffusion match or mismatch could be shown in 63 of 64 patients.

CONCLUSION

Practice and experience with MR imaging in a stroke team significantly reduce the time and effort required to perform this technique and thus make 24-hour availability for MR imaging of stroke practical. Assessment of patients with hyperacute stroke is rapid and comprehensive. Image quality can be substantially improved by head immobilization and by mild sedation, if necessary.

Poliomyelitic-like illness in central European encephalitis

Central European encephalitis (CEE) may be accompanied by myeloradiculitic symptoms in up to 5% of patients. The authors report six patients with a myelitic form of CEE mimicking acute poliomyelitis with bulbar and arm predominance and a poor prognosis. Three patients died. Of the survivors, only one can perform most activities of daily living, but still needs assisted ventilation at night. Autopsy in one patient showed severe cervicothoracic inflammation with changes almost exclusively in anterior horn cells and roots, as typically seen in poliomyelitis.

Monitoring intravenous recombinant tissue plasminogen activator thrombolysis for acute ischemic stroke with diffusion and perfusion MRI

BACKGROUND AND PURPOSE

Intravenous recombinant tissue plasminogen activator (rtPA) administration is an effective therapy for ischemic stroke when initiated within 3 hours and possibly up to 6 hours after symptom onset. To improve patient selection, a fast diagnostic tool that allows reliable diagnosis of hemorrhage and ischemia, vessel status, and tissue at risk at an early stage may be useful. We studied the feasibility of stroke MRI for the initial evaluation and follow-up monitoring of patients undergoing intravenous thrombolysis.

METHODS

Stroke MRI (diffusion- and perfusion-weighted imaging [DWI and PWI, respectively], magnetic resonance angiography, and T2-weighted imaging) was performed before, during, or after thrombolysis and on days 2 and 5. We assessed clinical scores (National Institutes of Health Stroke Scale [NIHSS], Scandinavian Stroke Scale [SSS], Barthel Index, and Rankin scale) at days 1, 2, 5, 30, and 90. Furthermore, we performed volumetric analysis of infarct volumes on days 1, 2, and 5 as shown in PWI, DWI, and T2-weighted imaging.

RESULTS

Twenty-four patients received rtPA within a mean time interval after symptom onset of 3.27 hours and stroke MRI of 3.43 hours. Vessel occlusion was present in 20 of 24 patients; 11 vessels recanalized (group 1), and 9 did not (group 2). The baseline PWI lesion volume was significantly larger (P=0.008) than outcome lesion size in group 1, whereas baseline DWI lesion volume was significantly smaller (P=0.008) than final infarct size in group 2. Intergroup outcome differed significantly for all scores at days 30 and 90 (all P<0.01). Intragroup differences were significant in group 1 for change in SSS and NIHSS between day 1 and day 30 (P=0.003) and for SSS only between day 1 and day 90 (P=0.004).

CONCLUSIONS

Stroke MRI provides comprehensive prognostically relevant information regarding the brain in hyperacute stroke. Stroke MRI may be used as a single imaging tool in acute stroke to identify and monitor candidates for thrombolysis. It is proposed that stroke MRI is safe, reliable, and cost effective; however, our data do not prove this assumption. Early recanalization achieved by thrombolysis can save tissue at risk if present and may result in significantly smaller infarcts and a significantly better outcome.

[Skull and brain injuries in children]

Our contribution reviews the diagnostic algorithm of head injuries in children. According to the Heidelberg consensus on head injury, patients should be divided into three risk groups. In low-risk patients clinical observation is the method of choice and radiological examinations are usually unnecessary. Patients at medium risk should be observed carefully. Sometimes neurosurgical consultation or CT is necessary. High risk patients in most instances need CT and neurosurgical consultation. Skull X-ray is helpful only in selected cases. A simple fracture as demonstrated by skull X-ray has no therapeutic consequence. However, normal findings in skull X-ray do not exclude intracranial injury. CT is the method of choice to detect intracranial hemorrhage, epi- or subdural hematoma and cerebral contusion. If patients present with severe clinical deficits, CT allows characterization of lesions and initiation of specific therapy.

A standardized MRI stroke protocol: comparison with CT in hyperacute intracerebral hemorrhage

BACKGROUND AND PURPOSE

Diagnostic imaging in hyperacute ischemic stroke has been revolutionized by the introduction of diffusion- and perfusion-weighted MRI (DWI and PWI). CT, however, is still needed to exclude intracerebral hemorrhage (ICH). The purpose of our study was to determine the diagnostic accuracy of a standardized, multimodal MRI (mMRI) stroke protocol in the qualitative and quantitative assessment of hyperacute ICH (<6 hours).

METHODS

We investigated 9 patients with hyperacute ICH with CT followed immediately by a standardized mMRI stroke protocol (DWI, PWI [T2*-WI], FLAIR, T2-WI, and MRA). The time interval between MRI and symptom onset ranged from 3 hours to 5 hours 45 minutes. We analyzed and compared the size of the hematoma on CT and all mMRI images by semiautomatic volumetry.

RESULTS

ICH was unambiguously identified on the basis of all mMRI sequences. With increasing susceptibility effect (T2*-WI), the ICH, appearing as an area of hyperintensity with central signal loss, became qualitatively most evident. Regarding quantitation, T2*-WI overestimated (median and mean difference, 18.9%/17.8%; SD final sigma=24.4%) and DWI correlated best (median and mean difference, 3.97%/-4.36%; SD final sigma=37. 42%) with hematoma size on CT.

CONCLUSIONS

Multimodal stroke MRI is as reliable as CT in the assessment of hyperacute ICH. Therefore, additional CT is no longer necessary to rule out ICH in hyperacute stroke. The use of mMRI alone in the diagnostic workup of a hyperacute stroke patient saves time and costs while rendering all the critical information needed to initiate an optimal treatment.