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Julio A Chalela

Publications and source records attributed to Julio A Chalela.

At least 19 recordsLinked to original sources
PubMed2006

Cerebellar hemorrhage caused by remote neurological surgery.

INTRODUCTION: Intracranial hemorrhage usually occurs as a complication of hypertension, coagulopathy, or trauma. In rare instances, remote cerebellar hemorrhage (RCH) may complicate supratentorial or spinal surgery. METHODS: Retrospective case series study. RESULTS: We describe three cases of RCH complicating spinal and cranial surgical procedures associated with cerebrospinal fluid hypotension. CONCLUSIONS: Remote cerebellar intracranial hemorrhage may complicate neurosurgical procedures in which cerebrospinal fluid hypotension occurs.

Aged↗
PubMed2005

The association between neurological deficit in acute ischemic stroke and mean transit time: comparison of four different perfusion MRI algorithms.

The purpose of our study was to identify the perfusion MRI (pMRI) algorithm which yields a volume of hypoperfused tissue that best correlates with the acute clinical deficit as quantified by the NIH Stroke Scale (NIHSS) and therefore reflects critically hypoperfused tissue. A group of 20 patients with a first acute stroke and stroke MRI within 24 h of symptom onset were retrospectively analyzed. Perfusion maps were derived using four different algorithms to estimate relative mean transit time (rMTT): (1) cerebral blood flow (CBF) arterial input function (AIF)/singular voxel decomposition (SVD); (2) area peak; (3) time to peak (TTP); and (4) first moment method. Lesion volumes based on five different MTT thresholds relative to contralateral brain were compared with each other and correlated with NIHSS score. The first moment method had the highest correlation with NIHSS (r = 0.79, P < 0.001) followed by the AIF/SVD method, both of which did not differ significantly from each other with regard to lesion volumes. TTP and area peak derived both volumes, which correlated poorly or only moderately with NIHSS scores. Data from our pilot study suggest that the first moment and the AIF/SVD method have advantages over the other algorithms in identifying the pMRI lesion volume that best reflects clinical severity. At present there seems to be no need for extensive postprocessing and arbitrarily defined delay thresholds in pMRI as the simple qualitative approach with a first moment algorithm is equally accurate. Larger sample sizes which allow comparison between imaging and clinical outcomes are needed to refine the choice of best perfusion parameter in pMRI.

Aged↗
PubMed2005

MRI screening before standard tissue plasminogen activator therapy is feasible and safe.

BACKGROUND AND PURPOSE: MRI screening for thrombolytic therapy may improve patient selection. Alternatively, it may excessively delay treatment and thereby lead to worse outcomes. We hypothesized that times to treatment and outcomes in a stroke center with immediate MRI access and interpretation would not differ from those of the typical clinical practice. METHODS: We compared the results of 120 consecutive patients treated with intravenous tissue plasminogen activator (tPA) within 3 hours of onset at our center with those of the 2 largest multicenter registries of tPA use. In addition to standard criteria, MRI specific eligibility criteria were applied in 97 patients. MRI was not performed in 23 patients because of contraindications to MRI or late patient arrival (>2.5 hours). Outcomes were the modified Rankin Scale (mRS) obtained at 3 months. RESULTS: Times to treatment (median door-to-needle time 81.5 minutes; median onset-to-needle time 135 minutes) and outcomes (mRS 0 to 1, 40.8%; mRS 0 to 2, 47.5%) were not inferior to those of the typical clinical practice. Door-to-needle time was shorter in computed tomography (CT) screening (67.5+/-22.5 minutes; n=23) than in MRI screening (86.8+/-21.5 minutes; n=97; P<0.001). However, outcomes were not different between MRI screening (mRS 0 to 1, 42.3%; mRS 0 to 2, 49.5%) and CT screening (mRS 0 to 1, 34.8%; mRS 0 to 2, 39.1%). Neither times to treatment nor MRI screening was predictive of outcomes. CONCLUSIONS: These data demonstrate that MRI screening before tPA therapy is feasible and not associated with unacceptable times to treatment or outcomes.

Adult↗
PubMed2005

Stroke in the tropics.

Similar to northern developed countries, cerebrovascular disease is a leading cause of morbidity and mortality in tropical countries. The epidemiology of stroke in the tropics is different from one tropical region to another and from the tropics to northern latitudes. In tropical regions, stroke is due to the conventional mechanisms encountered in other latitudes, as well as unusual causative mechanisms unique to the tropics. In tropical regions, infectious causes of stroke and nonatherosclerotic mechanisms are more common than in nontropical areas. Our current knowledge of stroke in the tropics is limited by the financial restrictions existing in such regions limiting health care delivery and epidemiological research.

Genetic Diseases, Inborn↗
PubMed2005

Diagnostic and prognostic value of early MR Imaging vessel signs in hyperacute stroke patients imaged <3 hours and treated with recombinant tissue plasminogen activator.

BACKGROUND AND PURPOSE: Analogous to the CT hyperattenuated vessel sign (HMCAS), MR imaging may show hypo- or hyperintense vessels in acute ischemic stroke (AIS) patients. We assessed the diagnostic and prognostic strength of early MR imaging vessel signs in AIS patients treated with intravenous thrombolysis (IVT) within 3 hours of the onset of symptoms. METHODS: We studied AIS patients both treated with IVT and stroke MR imaged within 3 hours of the onset of symptoms and at 2 hours and 24 hours after treatment. We assessed the presence or absence of early vessel signs (hyperintense fluid-attenuated inversion recovery sign [FLAIR HVS]; gradient-echo susceptibility vessel sign [GRE SVS]) compared with a combined MR angiography/perfusion-weighted imaging reference and their strength for predicting clinical outcome (favorable vs. poor, independent vs. dependent, or dead, death), recanalization (by clot composition and flow), and hemorrhage in uni- and multivariate analysis. RESULTS: Fifty-six patients (age range, 76 years +/- 13 years; median National Institutes of Health stroke scale score [NIHSSS], 11) met the inclusion criteria. Forty-four patients (78.6%) had a vessel occlusion at baseline; 22 of them (50%) recanalized. Nineteen patients (33.9%) suffered some form of intracranial hemorrhage (ICH), 24 patients (42.9%) had an independent outcome, 18 patients (32.1%) a favorable outcome, and 14 patients died. Compared with our combined reference for vessel status PWI/MRA, the sensitivities of CT HMCAS, FLAIR HVS, and GRE SVS were 40%, 66%, and 34%, respectively, and improved during the hours that followed. Localization was accurately reflected by FLAIR HVS but not by GRE SVS. Only NIHSSS and age were independent predictors for recanalization and all clinical outcomes in multiple logistic regression analysis. CONCLUSION: Although early vessel signs can be helpful in the diagnosis of intravascular disease, they do not independently predict recanalization, ICH, or any of the three clinical outcomes in a multivariate logistic regression model. Thrombus composition as reflected by signal intensity characteristics on GRE and FLAIR does not predict the therapeutic effect of IVT.

Aged↗
PubMed2004

Comparison of MRI and CT for detection of acute intracerebral hemorrhage.

CONTEXT: Noncontrast computed tomography (CT) is the standard brain imaging study for the initial evaluation of patients with acute stroke symptoms. Multimodal magnetic resonance imaging (MRI) has been proposed as an alternative to CT in the emergency stroke setting. However, the accuracy of MRI relative to CT for the detection of hyperacute intracerebral hemorrhage has not been demonstrated. OBJECTIVE: To compare the accuracy of MRI and CT for detection of acute intracerebral hemorrhage in patients presenting with acute focal stroke symptoms. DESIGN, SETTING, AND PATIENTS: A prospective, multicenter study was performed at 2 stroke centers (UCLA Medical Center and Suburban Hospital, Bethesda, Md), between October 2000 and February 2003. Patients presenting with focal stroke symptoms within 6 hours of onset underwent brain MRI followed by noncontrast CT. MAIN OUTCOME MEASURES: Acute intracerebral hemorrhage and any intracerebral hemorrhage diagnosed on gradient recalled echo (GRE) MRI and CT scans by a consensus of 4 blinded readers. RESULTS: The study was stopped early, after 200 patients were enrolled, when it became apparent at the time of an unplanned interim analysis that MRI was detecting cases of hemorrhagic transformation not detected by CT. For the diagnosis of any hemorrhage, MRI was positive in 71 patients with CT positive in 29 (P<.001). For the diagnosis of acute hemorrhage, MRI and CT were equivalent (96% concordance). Acute hemorrhage was diagnosed in 25 patients on both MRI and CT. In 4 other patients, acute hemorrhage was present on MRI but not on the corresponding CT--each of these 4 cases was interpreted as hemorrhagic transformation of an ischemic infarct. In 3 patients, regions interpreted as acute hemorrhage on CT were interpreted as chronic hemorrhage on MRI. In 1 patient, subarachnoid hemorrhage was diagnosed on CT but not on MRI. In 49 patients, chronic hemorrhage, most often microbleeds, was visualized on MRI but not on CT. CONCLUSION: MRI may be as accurate as CT for the detection of acute hemorrhage in patients presenting with acute focal stroke symptoms and is more accurate than CT for the detection of chronic intracerebral hemorrhage.

Acute Disease↗
PubMed2004

Early magnetic resonance imaging findings in patients receiving tissue plasminogen activator predict outcome: Insights into the pathophysiology of acute stroke in the thrombolysis era.

We measured ischemic brain changes with diffusion and perfusion MRI in 42 ischemic stroke patients before and 2 hours (range approximately 1.5 to 4.5 hours) after standard intravenous tissue plasminogen activator (tPA) therapy. The median time from stroke onset to tPA was 131 minutes. Clinical and MRI variables (change in perfusion and/or diffusion weighted lesion volume) were compared between those with excellent outcome defined as 3-month modified Rankin score (mRS) of 0 to 1 and those with incomplete recovery (mRS >1). In multivariate logististic regression analysis, the most powerful independent predictor for excellent outcome was improved brain perfusion: hypoperfusion volume on mean transit time (MTT) map decrease >30% from baseline to 2-hour post tPA scan (p=0.009; odds ratio [95% confidence interval], 20.7 [2.1-203.9]). Except for age < 70 years, no other baseline clinical or imaging variable was an independent predictor of outcome. We propose MTT lesion volume decrease more than 30% 2 hours after tPA as an early marker of long-term clinical benefit of thrombolytic therapy.

Adult↗
PubMed2004

Early blood-brain barrier disruption in human focal brain ischemia.

Loss of integrity of the blood-brain barrier (BBB) resulting from ischemia/reperfusion is believed to be a precursor to hemorrhagic transformation (HT) and poor outcome. We used a novel magnetic resonance imaging marker to characterize early BBB disruption in human focal brain ischemia and tested for associations with reperfusion, HT, and poor outcome (modified Rankin score >2). BBB disruption was found in 47 of 144 (33%) patients, having a median time from stroke onset to observation of 10.1 hours. Reperfusion was found to be the most powerful independent predictor of early BBB disruption (p = 0.018; odds ratio, 4.09; 95% confidence interval, 1.28-13.1). HT was observed in 22 patients; 16 (72.7%) of those also had early BBB disruption (p < 0.001; odds ratio, 8.11; 95% confidence interval, 2.85-23.1). In addition to baseline severity (National Institutes of Health Stroke Scale score >6), early BBB disruption was found to be an independent predictor of HT. Because the timing of the disruption was early enough to make it relevant to acute thrombolytic therapy, early BBB disruption as defined by this imaging biomarker may be a promising target for adjunctive therapy to reduce the complications associated with thrombolytic therapy, broaden the therapeutic window, and improve clinical outcome.

Aged↗
PubMed2004

Update on stroke.

PURPOSE OF REVIEW: This review highlights some advances in the areas of epidemiology, therapy, and imaging of acute stroke. RECENT FINDINGS: Studies published in 2003 provided new insights into the epidemiology of stroke. The African American Antiplatelet Stroke Prevention Study found that traditional stroke risk factors are still undiagnosed and undertreated, particularly in minorities. Cohort studies have identified incident silent infarcts as risk factors for stroke and history of type I diabetes as a risk factor for death in patients with acute stroke. Cervical artery dissection, on the other hand, seems to have a benign course. Imaging has become an important tool for understanding the pathophysiology of stroke, as demonstrated in recent publications. New studies have shown the prognostic value of magnetic resonance imaging: it can predict the volume of ischemic tissue that will progress to infarction and detects cerebral microbleeds - a risk factor for intracranial hemorrhage. Computed tomographic scanning may have a role in selecting patients for thrombolysis, particularly when validated scales are used. Despite the barriers to the use of tissue plasminogen activator in the treatment of patients with stroke, data published this year show that it is a safe medication when used routinely in community and university hospitals. In addition to thrombolysis, other general medical measures, such as glucose control and adequate attention to nutritional status, can help improve the outcome of patients with stroke. SUMMARY: In acute stroke, recognition and modification of risk factors continue to be challenging tasks. Treatment of acute stroke should involve thrombolysis and attention to medical conditions that may influence outcome. New applications of magnetic resonance imaging and computed tomography may help guide stroke therapy.

Brain Ischemia↗
PubMed2004

Acute stroke patients are being underfed: a nitrogen balance study.

INTRODUCTION: Patients with acute neurological illness may be hypercatabolic. The Harris-Benedict Equation (HBE) is used to estimate energy needs in acute stroke. A "stress factor" for stroke does not exist, and it is not known if the HBE accurately estimates the energy expenditure needs in acute ischemic or hemorrhagic stroke. We sought to assess nitrogen balance in patients with acute stroke and to determine the variables associated with negative nitrogen balance. MATERIALS AND METHODS: This was a case series, single-center study. Eligibility criteria included acute stroke requiring enteral nutrition, tolerating tube feedings at goal, normal urine output, and no underlying catabolic illness. Enteral feeding was adjusted to meet HBE requirements. After 24 hours of goal feeding, a 12-hour urine collection for nitrogen excretion was done. We determined if any of the following variables were associated with negative nitrogen balance: gender, glucose 6.6 mmol/L or more, age 80 years or older, National Institutes of Health Stroke Scale (NIHSS) 20 or higher, mechanical ventilation, and diabetes mellitus. RESULTS: We studied 27 patients (10 with intracranial hemorrhages and 17 with ischemic strokes) during an 18-month period. The median age was 80 (range: 48-90), and the median NIHSS was 19 (range: 4-38). The median time to feeding was 2 days (range: 1-8), the median time from onset to nitrogen balance was 5 days (range: 2-11), and the median interval between initiation of feeding and nitrogen collection was 2 days (range: 1-5)Negative nitrogen balance was seen in 12 of 27 (44%) patients. There was no relation between age, NIHSS, stroke type, admission glucose, history of diabetes, and mechanical ventilation use and nitrogen balance. Only 11 of 27 patients were anabolic. CONCLUSION: Critically ill stroke patients are being underfed using the current methods to estimate caloric needs. Hypercatabolism is common in acute stroke; clinical variables do not seem to allow prediction of this catabolic state.

Aged↗
PubMed2004

Myocardial injury in acute stroke: a troponin I study.

INTRODUCTION: Acute cerebrovascular insults can induce a variety of cardiac changes. We sought to describe the findings in a cohort of patients who had an acute stroke in whom Troponin I (TI) was sampled to determine the presence of associated myocardial damage. MATERIALS AND METHODS: This is a retrospective case series study. The investigators identified all patients who had an acute stroke in whom TI had been sampled. Demographics, stroke severity as determined by National Institutes of Health Stroke Scale (NIHSS), stroke location, electrocardiogram (EKG) results, echocardiography results, and cardiology evaluation were obtained from the stroke database or the medical records. Logistic regression analysis was performed to determine the clinical and paraclinical variables associated with TI elevation. RESULTS: During a 14-month period, 191 patients were studied, but TI levels were available in only 160 (84%) of the 191 patients. The sample was composed of 89 (55%) men and 71 (45%) women, with a median age of 76 years. Elevated TI occurred in 10 (6%) of the 160 patients. EKG changes suggestive of cardiac ischemia occurred in 2 of the 10 patients with high TI who had a stroke. In the remainder patients' TI elevations occurred in the absence of EKG or echocardiographic abnormalities. High NIHSS but no other variable was associated with TI elevation (p=.02). Ventricular arrhythmias, congestive heart failure, post-infarct pericarditis, and sudden death did not occur. CONCLUSION: In this limited sample, elevated TI occurred in 6% of the patients with acute stroke and was associated with severe stroke. Although in some patients who have acute stroke, TI elevation may represent coronary ischemia, in others it may reflect neurogenic-induced cardiac injury.

Adult↗
PubMed2004

Pseudo-subarachnoid hemorrhage: report of three cases and review of the literature.

Subarachnoid hemorrhage (SAH) appears on CT as hyperdensity in the subarachnoid space. In rare circumstances a similar appearance may occur in the absence of subarachnoid blood, a finding that has been termed "pseudo-subarachnoid hemorrhage." We describe three patients who presented with abrupt alterations in mental status in whom CT falsely suggested SAH, and we review the literature regarding this imaging finding. In contrast to prior reports, all three of our patients had a favorable outcome.

Adult↗
PubMed2004

Magnetic resonance imaging in the evaluation of intracranial hemorrhage.

Magnetic resonance imaging is emerging as a valuable tool for the urgent evaluation of patients with acute stroke. This review focuses on the applications of magnetic resonance imaging in the diagnosis and management of intracranial hemorrhage. The biophysical properties of blood in the neuroaxis and the magnetic resonance imaging evolution of intracranial bleeding are reviewed. The potential applications of magnetic resonance imaging in the evaluation and therapy of specific types of intracranial hemorrhage are discussed. Emphasis is made on the superiority of magnetic resonance imaging in detecting intracranial hemorrhage and ischemic stroke. Although there is some hesitation to perform magnetic resonance imaging to evaluate acute intracranial hemorrhage, there is strong evidence that magnetic resonance imaging is not inferior to computerized tomography in this clinical setting. In the era of acute stroke intervention, magnetic resonance imaging offers significant advantages over computed tomography.

Humans↗
PubMed2004

Multiple cerebral microbleeds: MRI marker of a diffuse hemorrhage-prone state.

BACKGROUND: Recent reports have indicated that cerebral microbleeds (CMBs) detected on gradient-echo (GRF) magnetic resonance imaging may be a risk factor for therapy related intracranial hemorrhages (ICHs). CASE DESCRIPTION: The authors describe 3 patients with multiple CMBs in whom ICHs occurred either after tissue plasminogen activator administration or after the initiation of antiplatelet therapy. Hemorrhages occurred in brain areas with normal appearances on GRE imaging and remote from the CMBs. CONCLUSION: Multiple CMBs may signal a diffuse hemorrhage-prone vasculopathy.

Aged↗
PubMed2003

Association of ischemic lesion patterns on early diffusion-weighted imaging with TOAST stroke subtypes.

BACKGROUND: Different topographic patterns in patients who experience an acute ischemic stroke may be related to specific stroke causes. OBJECTIVE: To determine if lesion patterns on early diffusion-weighted imaging (DWI) are associated with stroke subtypes determined by the TOAST (Trial of ORG 10172 in Acute Stroke Treatment) classification. DESIGN: Cross-sectional study. SETTING: General community hospital. Patients We studied 172 consecutive ischemic stroke patients with a symptomatic lesion on DWI performed within 24 hours of stroke onset. MAIN OUTCOME MEASURES: Lesion patterns on DWI were classified into single lesions (corticosubcortical, cortical, subcortical > or =15 mm, or subcortical <15 mm), scattered lesions in one vascular territory (small scattered lesions or confluent with additional lesions), and multiple lesions in multiple vascular territories (in the unilateral anterior circulation, in the posterior circulation, in bilateral anterior circulations, or in anterior and posterior circulations). RESULTS: We found an overall significant relationship between DWI lesion patterns and TOAST stroke subtypes (P<.001). Corticosubcortical single lesions (P =.01), multiple lesions in anterior and posterior circulations (P =.03), and multiple lesions in multiple cerebral circulations (P =.008) were associated with cardioembolism. Multiple lesions in the unilateral anterior circulation (P =.04) and small scattered lesions in one vascular territory (P =.06) were related to large-artery atherosclerosis. Nearly half (11/23) of the patients with a single subcortical lesion that was 15 mm or larger were classified as having cryptogenic strokes (P =.001), although 9 of these patients had a classic lacunar syndrome without cortical hypoperfusion. CONCLUSIONS: Early DWI lesion patterns are associated with specific stroke causes. Conventional 15-mm criteria for lacunes, however, may underestimate the diagnosis of small-vessel occlusion with DWI.

Adult↗
PubMed2003

Early ischemic lesion recurrence within a week after acute ischemic stroke.

Previous observations suggested that multiple ischemic lesions on diffusion-weighted imaging (DWI) are common in acute stroke patients. We hypothesized that a source of these multiple lesions was the recurrence of ischemic lesions within a week after a clinically symptomatic stroke. We analyzed 99 acute ischemic stroke patients scanned within 6 hours of onset and at subsequent times within the first week. Ischemic lesion recurrence was defined as any new lesion separate from the index lesion. Recurrent lesions occurring outside initial perfusion deficit were termed 'distant lesion recurrence'. We estimated the hazard ratio (HR) of recurrence associated with clinical and imaging characteristics using log-rank test. Any lesion recurrence was found in 34%, with distant lesion recurrence in 15%, while clinical recurrence was evident in 2%. Initial multiple DWI lesions were associated with any lesion recurrence (HR, 2.83; 95% confidence interval [CI], 1.65-10.29; p = 0.002) and with distant lesion recurrence (HR, 5.99; 95% CI, 4.05-64.07; p < 0.0001). Large-artery atherosclerosis was the most frequent stroke subtype associated with any lesion recurrence (p = 0.026). These results may indicate a prolonged state of increased ischemic risk over the first week and suggest DWI as a possible surrogate measure for recurrent stroke.

Acute Disease↗
PubMed2003

Modified National Institutes of Health Stroke Scale can be estimated from medical records.

BACKGROUND AND PURPOSE: The 15-item National Institutes of Health Stroke Scale (NIHSS) is a quantitative measure of stroke-related neurological deficit with established reliability and validity for use in clinical research. An abridged 11-item modified NIHSS (mNIHSS) has been described that simplifies or eliminates redundant and less reliable items. We aimed to determine whether the mNIHSS could be accurately abstracted from medical records to facilitate retrospective research. METHODS: We selected 39 patient records for which NIHSS scores were formally measured. Handwritten notes from medical records were abstracted, and NIHSS item scores were estimated by 5 raters blinded to actual scores. Estimated scores were compared among raters and with actual measured scores. RESULTS: Interrater reliability for total NIHSS on admission and discharge was excellent, with intraclass correlation coefficients (ICCs) of 0.85 and 0.79, respectively. However, ICCs for 2 items (facial palsy and dysarthria) were poor (<0.40). Interrater reliability for total mNIHSS was slightly greater, with ICCs of 0.87 and 0.89 on admission and discharge, respectively. None of the 11 mNIHSS items had poor reliability, 4 were moderate (ICC, 0.40 to 0.75), and 7 were excellent (ICC >0.75). Sixty-two percent of estimated total NIHSS scores were within 2 points of actual scores and 91% were within 5 points, whereas 70% of estimated total mNIHSS scores were within 2 points and 95% were within 5 points. CONCLUSIONS: The mNIHSS can be estimated from medical records with a high degree of reliability and validity. In retrospective assessment of stroke severity, the mNIHSS performs better than the standard NIHSS and may be easier to use because it has fewer and simpler items.

Humans↗