Background: Many patients may be mentally incompetent or physically unable to give informed consent at the acute stage of stroke. Accordingly, we aimed to investigate the modalities of informed consent in urgent therapeutic stroke trials, the awareness of patients and relatives regarding stroke clinical trials and the impact of decision making on patients and relatives. Methods: We present a study of 56 acute ischemic stroke patients who were randomized in 4 trials (2 trials testing neuroprotective agents, 1 testing thrombolysis and 1 testing antithrombotic agents). A standardized questionnaire was used to assess the modalities of informed consent in this setting. Results: The mean age was 67.1 (SD 12.6) years. The mean baseline Scandinavian Stroke Scale (SSS) score was 23.8 (SD 10.5). Only 13 patients (23% of cases) gave consent while relatives gave consent for 43 patients (77%). The main reason for not getting consent from the patient was aphasia in 29 patients (67.4%). Multiple logistic regression analysis showed that the two independent factors influencing the ability to give consent are age and baseline neurological deficit as assessed by the SSS score. Concerning the psychological impact of consent, none of the 10 patients who answered our questionnaire declared feeling uncomfortable when giving consent, while 7 out of the 13 relatives who could be reached declared they felt uncomfortable, mainly because of the psychological stress induced by urgent decision making. Conclusions: Our study emphasizes the specific ethical difficulties of informed consent in the setting of acute stroke research. Only a minority of patients are able to give consent at the acute stage. Increasing age and neurological deficit are independent predictors of inability to give consent. Thus, the responsibility for consent usually relies on relatives with potential inaccuracy of decision concerning the patient’s wish or even conflict of interest. Further evaluation of the psychological impact of decision on relatives is needed in this setting of acute stroke.

Objective: To evaluate clinical, biological, and pretreatment imaging variables for predictors of tissue plasminogen activator (tPA) related intracerebral haemorrhage (ICH) in stroke patients.Methods: 48 consecutive patients with hemispheric stroke were given intravenous tPA within seven hours of symptom onset, after computed tomography (CT) and magnetic resonance imaging (MRI) of the brain. Baseline diffusion weighted (DWI) and perfusion weighted (PWI) imaging volumes, time to peak, mean transit time, regional cerebral blood flow index, and regional cerebral blood volume were evaluated. The distribution of apparent diffusion coefficient ( ADC) values was determined within each DWI lesion.Results: The symptomatic ICH rate was 8.3% ( four of 48); the rate for any ICH was 43.8% ( 21 of 48). Univariate analysis showed that age, weight, history of hyperlipidaemia, baseline NIHSS score, glucose level, red blood cell count, and lacunar state on MRI were associated with ICH. However, mean 24 hour systolic blood pressure and a hyperdense artery sign on pretreatment CT were the only independent predictors of ICH. Patients with a hyperdense artery sign had larger pretreatment PWI and DWI lesion volumes and a higher NIHSS score. Analysis of the distribution of ADC values within DWI lesions showed that a greater percentage of pixels had lower ADCs (<400 x 10(-6) mm(2)/s) in patients who experienced ICH than in those who did not.Conclusion: Key clinical and biological variables, pretreatment CT signs, and MRI indices are associated with tPA related intracerebral haemorrhage.

Purpose: To deter-mine the evolution of the ischemic lesion volumes in a population treated with tissue plasminogen activator (t-PA). MRIs were performed before treatment and 24 hours later; final infarct size was evaluated 60 days later.Materials and Methods: A total of 42 patients with hemispheric stroke were recruited for a thrombolytic study. Intravenous t-PA was given after MRI within the first seven hours after stroke onset. Volumes were evaluated on day 0 and day 1 with diffusion-weighted imaging (DWI), on day 60 with T2-weighted imaging (T2WI), and recanalization was assessed based on day 1 MR angiography (MRA).Results: Lesion volume increased between day 0 and day 1, and decreased between day 1 and day 60. It was lower in the group of patients with recanalization on day 1 MRA.Conclusion: Volume analysis emphasizes the effectiveness of recanalization as a predictive factor for better outcome, based on final infarct size. The decrease in lesion volumes between day 1 and day 60 suggests that other factors leads to overestimation of day 1 abnormal diffusion volume. This could explain the delayed partial reversibility of the DWI abnormality.

HomeStrokeVol. 35, No. 12Predicting rtPA Associated ICH in Acute Stroke Free AccessLetterPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessLetterPDF/EPUBPredicting rtPA Associated ICH in Acute Stroke Askiel Bruno, MD Askiel BrunoAskiel Bruno Department of Neurology, Stroke Program, Indiana University School of Medicine, Indianapolis, Indiana Search for more papers by this author Originally published28 Oct 2004https://doi.org/10.1161/01.STR.0000146841.05980.a1Stroke. 2004;35:2762–2763Other version(s) of this articleYou are viewing the most recent version of this article. Previous versions: October 28, 2004: Previous Version 1 To the Editor:I read with interest the study by Trouillas et al from Lyon, France,1 describing a plasma marker associated with parenchymal brain hemorrhage in patients treated with intravenous recombinant tissue plasminogen activator (rtPA) for acute stroke. Unusually high D-dimer levels measured at 2 hours after beginning rtPA were associated with increased risk of parenchymal hemorrhage within 24 hours. This is useful information that could be translated to patients treated elsewhere with a similar protocol. However, the currently adopted protocol for intravenous rtPA treatment of acute stroke in the United States and many other countries is according to the American Stroke Association (ASA)2 and the American Academy of Neurology (AAN)3 guidelines, and these guidelines differ in 2 important ways from the protocol used in Lyon. I would like to point out that because of these differences, the findings from Lyon may not translate to centers that follow the ASA/AAN guidelines.First, the ASA/AAN guidelines do not recommend treatment beyond 3 hours after symptom onset, compared with up to 7 hours in Lyon. The mean delay to starting intravenous rtPA in Lyon was nearly 4 hours (based on a previous publication from that center),4 which is approximately 90 minutes later than in the United States. This difference may be important as longer exposure to brain ischemia, with greater injury to the blood vessels and surrounding tissue, may predispose to hemorrhagic complications more than shorter exposure.Second, the ASA/AAN guidelines advise against anticoagulation within 24 hours after rtPA treatment, compared with anticoagulation immediately after rtPA infusion in a considerable proportion of the patients in Lyon (exact proportion not stated). Anticoagulation is a well-established risk for parenchymal brain hemorrhage in multiple settings.Thus, elevated D-dimer levels in acute stroke patients treated with intravenous rtPA according to the ASA/AAN guidelines may not be predictive of parenchymal hemorrhage, as they are in patients treated with the Lyon study protocol. It would be useful to validate the findings from Lyon in patients treated within the ASA/AAN guidelines.1 Trouillas P, Derex L, Philippeau F, Nighoghossian N, Honnorat J, Hanss M, Ffrench P, Adeleine P, Dechavanne M. Early fibrinogen degradation coagulopathy is predictive of parenchymal hematomas in cerebral rt-PA thrombolysis: a study of 157 cases. Stroke. 2004; 35: 1323–1328.LinkGoogle Scholar2 Adams HP Jr, Adams RJ, Brott T, del Zoppo GJ, Furlan A, Goldstein LB, Grubb RL, Higashida R, Kidwell C, Kwiatkowski TG, Marler JR, Hademenos GJ. Guidelines for the early management of patients with ischemic stroke: a scientific statement from the Stroke Council of the American Stroke Association. Stroke. 2003; 34: 1056–1083.LinkGoogle Scholar3 Practice advisory: thrombolytic therapy for acute ischemic stroke–summary statement. Report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology. 1996; 47: 835–839.CrossrefMedlineGoogle Scholar4 Trouillas P, Nighoghossian N, Derex L, Adeleine P, Honnorat J, Neuschwander P, Riche G, Getenet JC, Li W, Froment JC, Turjman F, Malicier D, Fournier G, Gabry AL, Ledoux X, Berthezene Y, Ffrench P, Dechavanne M. Thrombolysis with intravenous rtPA in a series of 100 cases of acute carotid territory stroke: determination of etiological, topographic, and radiological outcome factors. Stroke. 1998; 29: 2529–2540.CrossrefMedlineGoogle ScholarstrokeahaStrokeStrokeStroke0039-24991524-4628Lippincott Williams & WilkinsResponse:Trouillas Paul, , MD, PhD, Derex Laurent, , MD, Philippeau Fréderic, , MD, Nighoghossian Norbert, , MD, Honnorat Jerome, , MD, Hanss Michel, , MD, French Patrick, , MD, Adeleine Patrice, , PhD, and Dechavanne Marc, , MD01122004We have been interested by the constructive remarks of Dr Bruno, who points out the need of further studies on hemostasis in rtPA protocols using ASA/AAN guidelines, in order to confirm the predictive value of degradation factors. Some clarifications must, however, be given.First, in our study,1 we measured fibrin(ogen) degradation products (FDP), which involve fragments of fibrinogen and fibrin, while D-dimers originate exclusively from fibrin.2 This postthrombolytic increase of FDP at 2 hours (early fibrinogen degradation coagulopathy) was correlated with a fibrinogen decrease, indicating an impact of rtPA, at least partial, on circulating fibrinogen. It may be possible that D-dimers, which have a different biological significance, would not be predictive of early parenchymal hematoma. However, this measurement is now included in our prospective hemostasis evaluation.Second, the Lyon protocol3,4 was designed in 1993, before the NINDS rtPA Study4 was published. At that time, the dose of rtPA, the window of administration, and the anticoagulant regimens were not standardized. However, the dose chosen was remarkably similar to that of the NINDS study (0.8 mg/kg). After the publication of the NINDS study results, we decided to continue the trial up to 200 patients, because our protocol was the unique opportunity to know what gave a slightly lower rtPA dose with a longer infusion time (90 minutes), a wider time window (7 hours), and precise postthrombolytic heparin regimens. In the cohort of 157 patients with hemostasis screening,1 the rate of symptomatic hemorrhage (3.8%) was lower than in part 1 (6%) and in part 2 (7%) of the NINDS study.4 Thus, the hemostasis disturbances that we described are not linked to a more intense hemorrhagic process.Third, the postthrombolytic FDP coagulopathy does not seem to be influenced by heparin. In our cohort, only 20.3% of patients had a regimen with immediate postthrombolytic unfractionated heparin. In several myocardial infarction trials including immediate use of intravenous heparin, an early FDP increase took place and was demonstrated to be correlated with bleeding complications, general or cerebral.5–11Thus, there is a chance that early fibrinogen degradation coagulopathy, predictive of early parenchymal hematomas, may be confirmed in rtPA protocols following the ASA/AAN guidelines, without heparin during the 24 first hours, as well as in intraarterial protocols like PROACT II using postthrombolytic heparin.12 Another answer may be given by the FRALYSE study, ongoing in France: this randomized, assessment blinded study, compares arms with the NINDS and Lyon protocols, with hemostasis and clinical parameters. Previous Back to top Next FiguresReferencesRelatedDetails December 2004Vol 35, Issue 12 Article InformationMetrics https://doi.org/10.1161/01.STR.0000146841.05980.a1PMID: 15514198 Originally publishedOctober 28, 2004 PDF download Advertisement

Admission delay remains the main cause for stroke patient exclusion from urgent therapeutic protocols. Public lack of knowledge about stroke symptoms may result in delay in seeking medical care and late presentation at hospital. Lack of knowledge of risk factors for stroke may also hamper compliance with stroke prevention practices. The aim of this prospective study using a standardized questionnaire was to evaluate the stroke awareness of acute stroke patients in France. From July 2, 1998 to July 2, 1999, 166 consecutive stroke patients were admitted at our stroke unit. Among the 91 patients who were able to answer the questionnaire during the first 48 hours, only 19 patients (21 p.cent) thought they were having a stroke before their arrival at the hospital, 38 patients (42 p.cent) did not know a single sign of stroke and 33 patients (36 p.cent) did not know a single risk factor of stroke. The most common risk factors named by the patients were smoking and hypercholesterolemia (named by 31 patients (34 p.cent) and 19 patients (21 p.cent), respectively). The most common warning signs named by the patients were paralysis of one side of body or one limb and speech disturbance (named by 40 patients (44 p.cent) and 15 patients (16 p.cent), respectively). Female sex and "knowing somebody who had a stroke" were significantly associated with awareness of signs of stroke in multivariate analysis. Educational public programs regarding stroke awareness are needed in France. Educational campaigns must stress the risk factors and symptoms of stroke and the appropriate response in the hopes of reducing admission delay and improving stroke prevention.

Background— Little is known about the coagulation factors as predictors of cerebral bleeding in rt-PA thrombolysis. The aim of this study was to determine what early coagulation parameters could predict early hemorrhagic lesions. Methods— Consecutive patients were included in the Lyon rt-PA protocol. Early hematomas (within 24 hours), diagnosed on an anatomoradiological basis (symptomatic and not symptomatic) were considered for the study. Fibrinogen and fibrin(ogen) degradation products (FDP) were assessed at entry and at 2 and 24 hours after the beginning of thrombolysis. Results— Of 157 patients, 11 had early parenchymal hematomas (7%), 31 had early hemorrhagic infarcts (19.7%), and 115 had no bleeding (73.2%). In logistic regression, FDP at 2 hours was the single predictor of parenchymal hematomas (OR: 2.5; CI: 1.09 to 5.8), whereas an increase of FDP >200 mg/L multiplied the odds of parenchymal hematoma by 4.95 (IC: 1.09 to 22.4). Early parenchymal hematomas were indicative of a poor prognosis at 3 months (P = 0.001). Conclusions— Early parenchymal hematomas appear as both “malignant” and exclusively related to an explosive increase of FDP at 2 hours, ie, an early fibrinogen degradation coagulopathy (EFDC). All patients scheduled to rt-PA thrombolysis should have an assay of FDP 2 hours after the beginning of thrombolysis: patients with an established EFDC (FDP >200 mg/L) should be monitored specifically, with no antithrombotic drug during the first 72 hours. Patients with FDP >100 mg should share the same monitoring.

We hypothesized that pretreatment magnetic resonance imaging (MRI) parameters might predict clinical outcome, recanalization and final infarct size in acute ischemic stroke patients treated by intravenous recombinant tissue plasminogen activator (rt-PA). MRI was performed prior to thrombolysis and at day 1 with the following sequences: magnetic resonance angiography (MRA), T2*-gradient echo (GE) imaging, diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI). Final infarct size was assessed at day 60 by T2-weighted imaging (T2-WI). The National Institutes of Health Stroke Scale (NIHSS) score was assessed prior to rt-PA therapy and the modified Rankin Scale (m-RS) score was assessed at day 60. A poor outcome was defined as a day 60 m-RS score >2. Univariate and multivariate logistic regression analyses were used to identify the predictors of clinical outcome, recanalization and infarct size. Forty-nine patients fulfilled the inclusion criteria. Baseline NIHSS score was the best independent indicator of clinical outcome (p=0.002). A worse clinical outcome was observed in patients with tandem internal carotid artery (ICA)+middle cerebral artery (MCA) occlusion versus other sites of arterial occlusion (p=0.009), and in patients with larger pretreatment PWI (p=0.001) and DWI (p=0.01) lesion volumes. Two factors predict a low rate of recanalization: a proximal site of arterial occlusion (p=0.02) and a delayed time to peak (TTP) on pretreatment PWI (p=0.05). The final infarct size was correlated with pretreatment DWI lesion volume (p=0.025). Recanalization was associated with a lower final infarct size (p=0.003). In conclusion, a severe baseline NIHSS score, a critical level of pretreatment DWI/PWI parameters and a proximal site of occlusion are predictive of a worse outcome after IV rt-PA for acute ischemic stroke.

Le délai d’admission des patients victimes d’accident vasculaire cérébral (AVC) demeure excessif. La reconnaissance précoce des symptômes peut raccourcir ce délai. L’étude prospective que nous rapportons visait à évaluer le niveau d’information concernant l’AVC des patients hospitalisés dans une unité neurovasculaire française. Du 2 juillet 1998 au 2 juillet 1999, un questionnaire standardisé visant à évaluer ce niveau d’information fut soumis à 166 patients consécutifs venant de présenter un AVC. Seuls 91 patients furent capables de répondre au questionnaire dans les 48 premières heures. Parmi ceux-ci, seuls 19 patients (21 p. 100) avaient pensé qu’ils étaient victimes d’une attaque cérébrale avant d’arriver à l’hôpital, 38 patients (42 p. 100) ne pouvaient citer aucun symptôme évocateur d’AVC et 33 patients (36 p. 100) ne pouvaient citer aucun facteur de risque d’AVC. Les facteurs de risque d’AVC les plus fréquemment cités furent : le tabagisme cité par 31 patients (34 p. 100) et l’hypercholestérolémie citée par 19 patients (21 p. 100). Aucun patient n’a cité les antécédents personnels d’accident ischémique cérébral transitoire ou constitué. Les symptômes évocateurs d’AVC les plus souvent cités furent : la paralysie d’un hémicorps ou d’un membre citée par 40 patients (44 p. 100) et les troubles du langage cités par 15 patients (16 p. 100). En analyse multivariée, le sexe féminin et le fait de « connaître quelqu’un ayant été victime d’une attaque cérébrale » sont des facteurs indépendants influençant la capacité à citer un(des) symptôme(s) évocateur(s) d’AVC. Des efforts d’information quant à la reconnaissance des symptômes et à la réaction appropriée doivent être déployés dans l’espoir de réduire le délai d’admission. Une meilleure information du public concernant les facteurs de risque apparaît également souhaitable afin d’améliorer la qualité de la prévention des maladies vasculaires.

Presented are the clinical data of 18 consecutive patients who were treated by IV recombinant tissue plasminogen activator (r-TPA) for suspected vertebrobasilar (VB) acute ischemia within 7 hours. The mean delay for treatment was 5 +/- 3.6 hours. Mean baseline NIH Stroke Scale score was 17 +/- 4. At 3 months, 10 patients were independent ( modified Rankin Scale [mRS] score = 0 to 2), whereas 8 patients showed a poor outcome (mRs = 3 to 6). IV r-TPA in VB ischemia in a 7-hour window may be safe and efficient.

The significance of early ischemic changes (EICs) on CT remains controversial. MRI may provide relevant information in patients with EICs. Methods: EICs were assessed in patients with acute ischemic stroke. MRI was promptly performed at presentation after CT and repeated on day 1. The relationship between EICs and MRI parameters was assessed with one-way ANOVA for analysis of continuous variables and by the χ2 test for the analysis of variables with a binary outcome. Results: Fourty-eight patients underwent CT and MR imaging before treatment with recombinant tissue plasminogen activator (age: 63 ± 14 years). EICs were graded as absent in 28 patients, <33% in 15 patients, and >33% of the middle cerebral artery (MCA) territory in 5 patients. NIHSS score was higher in patients with EICs that covered more than one third of the MCA territory (19 ± 3) compared to those without EICs (12 ± 5; p = 0.04). Patients who had major EICs had a larger acute lesion volume in diffusion-weighted imaging (DWI; 140 ± 78 cm3) compared to those without EICs (33 ± 51 cm3, p < 0.0001). Regional cerebral blood flow, regional cerebral blood volume, time to peak and mean transit time values were not significantly different in the study groups. Conclusion: EICs reflect mainly a larger DWI lesion.

In this prospective MRI study, we evaluated the impact of the site of occlusion on multiple baseline perfusion parameters and subsequent recanalization in 49 stroke patients who were given intravenous tissue plasminogen activator (tPA). Pretreatment magnetic resonance angiography (MRA) revealed an arterial occlusion in 47 patients: (1) internal carotid artery (ICA) + M1 middle cerebral artery (MCA) occlusion ( n =12); (2) M1 MCA occlusion ( n =19); (3) M2 MCA, distal branches of the MCA and anterior cerebral artery (ACA) occlusion ( n =16). Patients with ICA occlusion had significantly larger DWI, PWI and mismatch lesion volume on pretreatment MRI compared to patients with other sites of occlusion. The differences in cerebral blood flow (CBF) and peak height were significantly higher in patients with ICA occlusion compared to patients with other sites of occlusion ( P =0.03 and P =0.04, respectively). Day 1 MRA showed recanalization in 28 patients (60%). The rate of recanalization was significantly different depending on the site of occlusion: 33% in ICA + M1 MCA occlusion, 63% in M1 MCA occlusion and 81% in either M2 MCA, distal branches of the MCA or ACA occlusion ( P =0.002). Our data suggest that CBF and peak height are the most relevant MRI parameters to assess the severity of hemodynamic impairment in regard to the site of occlusion.

BACKGROUND:Old asymptomatic microbleeds (MBs) visualized on T2-weighted MRI are indicative of microangiopathy. They may be a marker of increased risk of intracerebral hemorrhage (ICH) following thrombolysis. However, data regarding this potential risk are limited.METHODS:A retrospective analysis of pretreatment T2-weighted MRI was performed in consecutive stroke patients who received intravenous tissue plasminogen activator (tPA). We aimed to assess the impact of MBs on the risk of cerebral bleeding. The frequency and location of MBs were assessed and compared with the location of ICH after thrombolysis.RESULTS:Forty-four patients were studied. MBs were present on pretreatment MRI in 8 cases (18.2%). At day 1, symptomatic ICH occurred in none of 8 patients with MBs versus 1 of 36 patients without (NS). At day 1, ICH occurred in 3 of 8 patients with MBs versus 10 of 36 patients without (NS). At day 7, symptomatic ICH occurred in 1 of 8 patients with MBs versus 2 of 36 patients without (NS). At day 7, ICH occurred in 5 of 8 patients with MBs versus 12 of 36 patients without (NS). No ICH occurred at the site of an MB. ICH occurred within the ischemic area in all patients who bled.CONCLUSIONS:Our study suggests that stroke patients with a small number of MBs on pretreatment MRI could be treated safely with thrombolysis. Larger prospective studies are needed to address the predictive value of detection of MBs with regard to the risk of tPA-induced ICH.

PURPOSE:Effective collateral blood flow seem to be an important factor associated with a small infarct volume and a good clinical outcome. We aimed to assess leptomeningeal collateral blood flow on source perfusion-weighted images in patients with acute stroke.MATERIALS AND METHODS:29 patients with proximal middle cerebral artery occlusion (MCA alone, n=17; MCA + internal carotid artery [ICA] occlusion, n=12) were evaluated with MRI at baseline before thrombolytic therapy, and at day 60. Clinical evaluation was performed at days 0 and 60 with the National Institutes of Health Stroke Scale (NIHSS) score, and at day 60 with the modified Rankin score. We assessed (on source images of the dynamic contrast-enhanced T2*-weighted perfusion [PWI] sequence) the presence of a hypointensity consistent with delayed contrast arrival within the global perfusion deficit (delayed perfusion sign). We analyzed the extent of the area demonstrating such delayed perfusion (DP area) on source images of the PWI sequence, and compared it with the global perfusion (GP) abnormality shown by time-to-peak maps. We calculated the Spearman rank correlation coefficient between the DP/GP ratio and: 1. age; 2. clinical scores; 3. site of occlusion [MCA alone versus ICA+MCA occlusion]; 4. DWI lesion size at day 0, and T2WI lesion size at day 60; 5. PWI-derived parameters (time-to-peak [TTP], relative cerebral blood volume [rCBV], relative cerebral blood flow [rCBF], and peak height). All tests were bilateral and a p value<0.05 was considered as significant.RESULTS:Delayed perfusion areas of various size were found within the global perfusion deficit in all patients. High DP/GP ratio values were significantly correlated with: 1. better clinical scores at day 0 and day 60 (all p<=0.04); 2. smaller lesions at day 0 DWI and at day 60 T2WI (all p<=0.004); 3. ICA patency (r=0.49, p=0.01); 4. lower TTP delays, and higher values of rCBV, rCBF, and peak height.CONCLUSION:These preliminary data suggest that a delayed contrast filling observed on native perfusion-weighted images may be a marker of leptomeningeal collateral blood flow, and may lead to better clinical and morphological outcomes in acute ischemic stroke.

In patients with acute ischemic stroke, early recanalization may save tissue at risk for ischemic infarction, thus resulting in smaller infarcts and better clinical outcome. The hypothesis that clinical and diffusion- and perfusion-weighted imaging (DWI, PWI) parameters may have a predictive value for early recanalization and final infarct size was assessed. Twenty-nine patients were prospectively enrolled and underwent sequential magnetic resonance imaging (1) within 6 hours from hemispheric stroke onset, before thrombolytic therapy; (2) at day 1; and (3) at day 60. Late infarct volume was assessed by T 2 -weighted imaging. At each time, clinical status was assessed by the National Institutes of Health Stroke Scale (NIHSS). Twenty-eight patients had arterial occlusion at day 0 magnetic resonance angiography (MRA). They were classified into two groups according to day 1 MRA: recanalization (n = 18) versus persistent occlusion (n = 10). Any significant differences between these groups were assessed regarding (1) PWI and DWI abnormality volumes, (2) relative and absolute time-to-peak (TTP) and apparent diffusion coefficient within the lesion on DWI; and (3) day 60 lesion volume on T 2 -weighted imaging. Univariate and multivariate logistic regression analysis showed that the most powerful predictive factors for recanalization were lower baseline NIHSS score and lower baseline absolute TTP within the lesion on DWI. The best predictors of late infarct size were day 0 lesion volume on DWI and day 1 recanalization. Early PWI and DWI studies and day 1 MRA provide relevant predictive information on stroke outcome.

Prediction of hemorrhagic transformation (HT) in patients treated by intravenous recombinant tissue-type plasminogen activator (rt-PA) is a challenging issue in acute stroke management. HT may be correlated with severe hypoperfusion. Signal changes may be observed at susceptibility-weighted magnetic resonance imaging (MRI) within large perfusion defects. A signal drop within cerebral veins at T2∗-weighted gradient-echo MRI may be expected in severe ischemia, and may indicate subsequent risk of HT. The authors prospectively searched for an abnormal visibility of transcerebral veins (AVV) within the ischemic area in patients with hemispheric ischemic stroke, before they were treated with intravenous rt-PA therapy. Any correlation between AVV and baseline clinical or MRI findings, or further HT, was noted. An AVV was present in 23 of 49 patients (obvious, n = 8; moderate, n = 15), and was supported by severe hemodynamic changes at baseline MRI. The AVV was correlated with the occurrence of parenchymal hematoma type 2 at computed tomography during the first week ( r = 0.44, P = 0.002). Five of six type 2 parenchymal hematomas occurred in association with obvious AVV. At multiple regression analysis, two baseline MRI factors had an independent predictive value for HT risk during the first week: the AVV and the cerebral blood volume ratio (Nagelkerke R2 = 0.48).

Purpose: Effective collateral blood flow seem to be an important factor associated with a small infarct volume and a good clinical outcome. We aimed to assess leptomeningeal collateral blood flow on source perfusion-weighted images in patients with acute stroke.Materials and methods: 29 patients with proximal middle cerebral artery occlusion (MCA alone, n=17; MCA + internal carotid artery [ICA] occlusion, n=12) were evaluated with MRI at baseline before thrombolytic therapy, and at day 60. Clinical evaluation was performed at days 0 and 60 with the National Institutes of Health Stroke Scale (NIHSS) score, and at day 60 with the modified Rankin score. We assessed (on source images of the dynamic contrast-enhanced T2*-weighted perfusion [PWI] sequence) the presence of a hypointensity consistent with delayed contrast arrival within the global perfusion deficit (delayed perfusion sign). We analyzed the extent of the area demonstrating such delayed perfusion (DP area) on source images of the PWI sequence, and compared it with the global perfusion (GP) abnormality shown by time-to-peak maps. We calculated the Spearman rank correlation coefficient between the DP/GP ratio and: 1. age; 2. clinical scores; 3. site of occlusion [MCA alone versus ICA+MCA occlusion]; 4. DWI lesion size at day 0, and T2WI lesion size at day 60; 5. PWI-derived parameters (time-to-peak [TTP], relative cerebral blood volume [rCBV], relative cerebral blood flow [rCBF], and peak height). All tests were bilateral and a p value <0.05 was considered as significant.Results: Delayed perfusion areas of various size were found within the global perfusion deficit in all patients. High DP/GP ratio values were significantly correlated with: 1. better clinical scores at day 0 and day 60 (all pless than or equal to0.04); 2. smaller lesions at day 0 DWI and at day 60 T2WI (all pless than or equal to0.004); 3. ICA patency (r=0.49, p=0.01); 4. lower TTP delays, and higher values of rCBV, rCBF, and peak height.Conclusion: These preliminary data suggest that a delayed contrast filling observed on native perfusion-weighted images may be a marker of leptomeningeal collateral blood flow, and may lead to better clinical and morphological outcomes in acute ischemic stroke.

The authors studied 16 consecutive cases of cerebral venous thrombosis (CVT). Clinical outcome was good or excellent in 14 patients. Comprehensive hypercoagulable screening was done at least 3 months after the onset of CVT, including evaluation of genetic coagulation disorders and plasma levels of homocysteine and factor VIII. This screening was positive in 12 patients (75%). An acquired prothrombotic factor was identified in 9 of these 12 patients. Elevation of factor VIII plasma level was the most common coagulation disorder (8 patients).