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Louis R Caplan

Publications and source records attributed to Louis R Caplan.

70 records · Page 4Linked to original sources
PubMed2002

Outcome at 30 days in the New England Medical Center Posterior Circulation Registry.

BACKGROUND: Vertebrobasilar disease is generally considered a condition with a poor prognosis because of high rates of mortality and severe disability. OBJECTIVE: To compare the outcomes of 407 patients entered in the New England Medical Center Posterior Circulation Registry with the reported results of other studies. RESULTS: In contrast, among 407 patients prospectively and consecutively studied in the New England Medical Center Posterior Circulation Registry, we found a low mortality rate at 30 days after onset (3.6%) and relatively low rates of major disability (18% using a Modified Rankin Disability Scale score). Thirty days after stroke, 28% of the patients had no disability and 51% had only a minor disability. Stroke location, stroke mechanism, and arteries involved predicted outcome. Basilar artery involvement, embolic stroke mechanism, and multiple posterior circulation intracranial territory involvement correlated with poor outcome. Patients with lesions in the basilar artery were 5 times more likely to have a poor outcome independent of other factors. Lesions in the middle and distal territories were each associated with a poor outcome in one third of the patients. CONCLUSION: In contrast with previous reports, we found that vertebrobasilar occlusive disease consists of a variety of different stroke mechanisms and vascular lesions, many with a good prognosis.

Aged↗
PubMed2002

Diagnosis of cerebral venous thrombosis with echo-planar T2*-weighted magnetic resonance imaging.

BACKGROUND: Magnetic resonance (MR) signal changes suggestive of cerebral venous thrombosis (CVT) on T1- and T2-weighted images may be subtle and their identification requires a high degree of suspicion. Magnetic resonance venography remains essential for definitive diagnosis. Recent reports have shown that T2(*)-weighted MR sequence is more sensitive than T1-weighted, T2-weighted, and fluid-attenuated inversion recovery (FLAIR) images in detecting subarachnoid and intracerebral hemorrhages, both of which can be seen in association with CVT. The value of T2*-weighted magnetic resonance imaging (MRI) in diagnosing CVT has not been well studied. OBJECTIVES: To investigate and describe T2*(susceptibility-weighted) MRI findings in 5 patients with CVT. METHODS: We reviewed our stroke database from May 1, 1997, through May 31, 2001. The diagnosis of CVT was made in 6 patients, 5 had an MRI with T2* sequence. We examined T2*/susceptibility-weighted images for these 5 patients to determine their ability, relative to T1-weighted, T2-weighted, and FLAIR sequences, to detect CVT. RESULTS: On T2*-weighted images, we were able to detect areas of hypointensities in the affected veins and/or sinuses in all 5 patients. Thrombosed veins and/or sinuses were more easily seen on T2*-weighted images than on any other MR sequence. The T2* sequence also allowed visualization of associated hemorrhagic venous infarcts, which were considerably less obvious on other MR sequences. CONCLUSIONS: The T2*-weighted MR sequence can be useful in rapid detection of CVT and may enable the diagnosis to be made prior to MR venography. This is particularly important in clinically unsuspected patients, in whom MR venography is rarely obtained.

Adult↗
PubMed2002

Spontaneous intracranial internal carotid artery dissection: report of 10 patients.

BACKGROUND: Spontaneous intracranial internal carotid artery (ICA) dissection is an uncommon cause of cerebral infarction, particularly when compared with the dissection of the ICA's cervical portion. Most reports describe extensive strokes with very high mortality rates. OBJECTIVE: To report the clinical and radiological findings of 10 patients with spontaneous intracranial ICA dissection. METHODS: Ten patients (5 women) were included with ages ranging from 15 to 59 years (mean age, 28 years). RESULTS: Nine patients had a stroke (1 had an associated subarachnoid hemorrhage), whereas 1 patient had only transient ischemic attacks. Severe retro-orbital or temporal headache followed by contralateral hemiparesis was the most common initial clinical symptom. No patient had vascular risk factors or a history of neck or head trauma. Stenosis of the supraclinoid portion of the ICA occurred in 8 patients, with extension to the middle cerebral artery or anterior cerebral artery in 2 patients each. Aneurysm formation in the ipsilateral anterior cerebral artery was seen in 1 patient. Two patients had a total occlusion of the supraclinoid portion of the ICA. All patients did well, with no (n = 3), mild (n = 4), or moderate (n = 3) disability on the Modified Rankin Scale during a 3-month follow-up period. CONCLUSIONS: Spontaneous intracranial ICA dissection can cause ischemic stroke with or without subarachnoid hemorrhage and should be considered in the differential diagnosis of intracranial ICA stenosis or occlusion, especially in young patients. Some patients survive with few or moderate deficits.

Adolescent↗
PubMed2002

Cell transplantation for stroke.

Cell transplantation has emerged as an experimental approach to restore brain function after stroke. Various cell types including porcine fetal cells, stem cells, immortalized cell lines, and marrow stromal cells are under investigation in experimental and clinical stroke trials. This review discusses the unique advantages and limitations of the different graft sources and emphasizes the current, limited knowledge about their biology. The survival, integration, and efficacy of neural transplants in stroke patients will depend on the type, severity, chronicity, adequacy of circulation, and location of the stroke lesion.

Bone Marrow Transplantation↗
PubMed2002

Significance of early CT signs in acute stroke. A CT scan-diffusion MRI study.

OBJECTIVE: To study the pathophysiology of early CT signs. BACKGROUND: Early CT signs, due to an increase in tissue water content, are commonly attributed to cytotoxic edema and development of irreversible injury. This may have important implications for thrombolysis. METHODS: In patients with acute ischemic stroke in the middle cerebral artery territory, the areas of early CT signs and diffusion weighted imaging (DWI) hypersignal were independently assessed and drawn on a standardized atlas. Then, patients were classified into three groups (early CT signs larger than, similar to or smaller than DWI hypersignal) and compared with perfusion weighted imaging (PWI). RESULTS: Of 16 patients, CT scanning was performed with a median time of 3 h after onset and early CT scan signs were recorded in 10/16 patients (62.5%). DWI signal hyperintensity was present in 15/16 (94%) patients. In 7/16 (43%) patients, the area with early CT scan signs was larger than the DWI lesion ('CT-larger group'). Only in 2/16 (12%) patients were the areas matching ('matching group'). In 7/16 (43%) the DWI lesion was larger than the early CT scan signs area ('DWI-larger group'). When compared with PWI, the areas of early CT signs were larger than DWI hypersignal and were matching with PWI abnormalities (rMTT) in 2 cases, suggesting that they may represent a reversible process. CONCLUSIONS: Early CT signs might have a potential dual fate: infarction or reversibility. Other techniques of recognizing reversible ischemic damage, such as DWI-PWI, are needed to improve acute stroke diagnosis and management.

Acute Disease↗
PubMed2002

Seizure at stroke onset: should it be an absolute contraindication to thrombolysis?

BACKGROUND: Current guidelines for the treatment of acute ischemic stroke exclude patients with seizure at stroke onset from consideration for thrombolytic therapy. It may be difficult to differentiate an ischemic stroke from postictal Todd's paralysis by clinical examination and noncontrast CT scan. Magnetic resonance imaging (MRI) with diffusion- (DWI) and perfusion-weighted images (PWI) and angiography (MRA) can be used to confirm the diagnosis of an acute ischemic process in the presence of concurrent seizures. METHODS: A case report of a patient who presented with seizures, in whom the combination of DWI/PWI MRI and MRA confirmed the diagnosis of an embolic ischemic stroke. The patient was treated with intravenous recombinant tissue plasminogen activator with clinical and radiological improvement. CONCLUSIONS: Treatment decisions with regard to thrombolysis in acute stroke patients should be based on parameters of cerebral perfusion, assessment of collateral blood flow and presence of potentially salvageable tissue. Modern neuroimaging techniques that can rapidly assess these variables, such as DWI/PWI MRI and MRA, can improve the current selection of patients who are likely to benefit from thrombolysis and extend its benefit to patients who would otherwise be excluded, such as those with seizures at stroke onset.

Aged↗
PubMed2002

Is the association of National Institutes of Health Stroke Scale scores and acute magnetic resonance imaging stroke volume equal for patients with right- and left-hemisphere ischemic stroke?

BACKGROUND AND PURPOSE: The National Institutes of Health Stroke Scale (NIHSS) is an established measure of neurological impairment; however, it can award more points for tests of presumed left-hemisphere function, such as language, than for tests of right-hemisphere function, such as neglect. This difference may be important if a low NIHSS score is used to exclude patients with right-hemisphere stroke from clinical trials or established treatments. The aim of this study was to investigate whether the relationship between acute NIHSS score and acute stroke volume as determined by acute diffusion- and perfusion-weighted MRI (DWI and PWI) differs between right- and left-sided stroke. METHODS: This was a retrospective study of 153 patients with acute stroke seen at Beth Israel Deaconess Medical Center between January 1995 and March 2000 who underwent an MRI examination and NIHSS within 24 hours of stroke onset. NIHSS score was recorded prospectively by the admitting stroke fellow at the time of acute presentation, immediately preceding imaging. Computerized volumetric analysis of the MRI lesions was performed by investigators blinded to clinical data. RESULTS: There were significant correlations between the acute NIHSS scores and acute DWI lesion volumes (r=0.48 right, r=0.58 left) and between acute NIHSS scores and perfusion-weight imaging hypoperfusion volumes (r=0.62 right, r=0.60 left). For patients with NIHSS scores of 0 to 5, the DWI volume of right cerebral lesions was greater than that of left-sided lesions (mean volume, 8.8 versus 3.2 cm3; P=0.04). Among patients with DWI lesions larger than the median volume (9 cm3), 8 of 37 with right-sided stroke had an NIHSS score of 0 to 5 compared with 1 of 39 patients with left-sided stroke (P=0.01). Multiple linear regression analysis revealed a significantly lower acute NIHSS on the right compared with the left side when adjusted for stroke volume on chronic T2 imaging (P=0.03). CONCLUSIONS: Patients with right-sided stroke may have a low NIHSS score despite substantial DWI lesion volume. Acute imaging information, such as that available with multimodal MRI, may be useful to identify patients for inclusion in acute stroke protocols when there is clinical uncertainty about eligibility. Prospective evaluation of criteria incorporating acute imaging data is required.

Adult↗
PubMed2002

The stroke patient who woke up: clinical and radiological features, including diffusion and perfusion MRI.

BACKGROUND AND PURPOSE: Time of stroke onset is uncertain for patients who wake from sleep with stroke. Functional imaging techniques may allow estimation of benefit and risk of acute stroke therapy. We compared the clinical and multimodal MRI findings of patients with uncertain stroke onset with those with known onset time. METHODS: Patients imaged within 24 hours of ischemic stroke onset between January 1997 and June 2000 were identified from a prospective stroke registry. Clinical and imaging data from patients with known stroke onset (group I) were compared with those who woke with stroke (group II). RESULTS: A total of 364 patients were identified, of whom 100 (27%) woke from sleep with stroke. Group I and group II did not differ in age, gender, National Institutes of Health Stroke Scale, or TOAST (Trial of Org 10172 in Acute Stroke Treatment) diagnoses. Time from stroke onset was shorter in group I (mean 6.0 versus 13.3 hours, P<0.001); time from detection did not differ between groups (6.0 versus 5.9 hours). Within 3 hours, diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI) lesion volumes were similar in both groups; DWI-PWI mismatch was present in 82% of group I and 73% of group II patients. Mean apparent diffusion coefficient of water (ADC) of group I patients was negatively associated with DWI volume (beta=-0.324, P=0.004) and time from stroke onset (beta=-0.238, P=0.031) in multivariate analysis. The mean ADC of group II patients was lower than that of group I patients within 3 hours of stroke detection (mean 556 versus 665 microm2/s, P<0.01), but individual group II patients had ADC values as high as 742 microm2/s, in addition to a DWI-PWI mismatch pattern. CONCLUSIONS: Onset time is uncertain in over one quarter of acute ischemic stroke patients. Clinical features of these patients do not differ significantly from those with known onset time. Some patients who wake with stroke seem to have favorable imaging characteristics for acute stroke therapy. Further study is needed to determine whether criteria for therapy based on imaging parameters can safely be applied to these patients.

Aged↗
PubMed2002

Clinical and vascular outcome in internal carotid artery versus middle cerebral artery occlusions after intravenous tissue plasminogen activator.

BACKGROUND AND PURPOSE: Early reperfusion is a predictor of good outcome in acute ischemic stroke. We investigated whether middle cerebral artery (MCA) occlusions have a better clinical outcome and proportion of recanalization compared with internal carotid artery (ICA) occlusion after standard treatment with intravenous (IV) tissue plasminogen activator (tPA). PATIENTS: In a retrospective analysis of our prospective stroke database between January 7, 1998, and January 30, 2002, we identified 36 consecutive patients who were treated with IV tPA within 3 hours after symptom onset of a stroke in the distribution of a documented ICA or MCA occlusion. The National Institutes of Health Stroke Scale (NIHSS) score was recorded before tPA, at 24 hours, 3 days, and 3 months after stroke. Three-month outcome was recorded by modified Rankin scale. Magnetic resonance angiography or computed tomographic angiography was obtained before tPA. The presence of recanalization was assessed by transcranial Doppler and/or magnetic resonance angiography within 3 days after stroke onset. RESULTS: Nineteen patients had MCA occlusion, and 17 had ICA-plus-MCA occlusion before tPA. Although there was no difference in age and NIHSS at day 0 between the 2 groups, the MCA group had a lower day 3 NIHSS score compared with the ICA group (P=0.006) in an ANCOVA. In addition, patients who had a MCA occlusion had lower day 1 and 3 NIHSS scores compared with the ICA group (P=0.04 and P=0.03, respectively; Wilcoxon rank sum). Similarly, NIHSS was significantly lower in patients who recanalized on days 1 and 3 (P=0.004 and P=0.003 respectively, Wilcoxon rank sum). When we adjusted for NIHSS score at day 0 in an ANCOVA, the adjusted mean was lower in the group that recanalized compared with the group that did not recanalize (P<0.001). There was a significant difference between the proportion of recanalization in the MCA group (15 of 17 recanalized, 88%) at 3 days after tPA compared with that of the ICA group (5 of 16 recanalized, 31%; P=0.001, Fisher exact test). The 3-month modified Rankin scale was not different between the 2 groups. CONCLUSIONS: Despite comparable age and NIHSS scores before IV tPA, MCA occlusions have lower day 1 and 3 NIHSS scores and higher proportion of recanalization compared with ICA occlusions. A combined IV/intra-arterial or mechanical thrombolysis may be needed to achieve early recanalization in ICA occlusions.

Adult↗
PubMed2002

Predictors of hemorrhagic transformation after intravenous recombinant tissue plasminogen activator: prognostic value of the initial apparent diffusion coefficient and diffusion-weighted lesion volume.

BACKGROUND AND PURPOSE: Hemorrhagic transformation (HT) is a potentially dangerous complication of thrombolytic therapy. Recent studies suggest that diffusion-weighted MRI (DWI) can help to predict the risk of intracerebral hemorrhage (ICH) after thrombolysis. We sought to examine which pretreatment DWI parameters and clinical data are predictive of ICH after intravenous thrombolysis. METHODS: We retrospectively reviewed our prospective stroke database for patients with ischemic stroke treated with intravenous recombinant tissue plasminogen activator (rtPA) within 3 hours from symptom onset who had DWI before treatment and MRI with T2* sequence or CT 24 to 48 hours later to assess for ICH over the past 4 years. We measured the volumes and voxel-by-voxel apparent diffusion coefficient (ADC) values of the initial DWI lesions and retrieved demographic data, risk factors, National Institutes of Health Stroke Scale (NIHSS) scores on admission, and blood tests results. We examined several variables using univariate and multivariate regression analyses to determine predictors of ICH. RESULTS: Twenty-nine patients fulfilled our inclusion criteria; 17 patients (58%) had ICH, and of these 4 (13%) had symptomatic ICH and fatal outcome. On univariate analysis, higher systolic blood pressure, NIHSS score, serum glucose level, volume of initial DWI lesion, and absolute number of voxels with ADC value < or =550x10(-6) mm2/s were statistically associated with ICH, and all were subjected to multivariate analysis. However, only the absolute number of voxels, ie, volume of ischemic tissue on DWI, with ADC < or =550x10(-6) mm2/s emerged as an independent predictor of ICH. CONCLUSIONS: Our findings suggest that volumetric ADC analysis can be used to assess ICH risk after thrombolysis. This may be particularly helpful if rtPA is to be given outside the 3-hour window.

Adult↗