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Biomedical subjects

S Tuhrim

Publications and source records attributed to S Tuhrim.

16 recordsLinked to original sources
PubMed1992

Features on initial computed tomography scan of infarcts with a cardiac source of embolism in the NINDS Stroke Data Bank.

BACKGROUND AND PURPOSE: The lack of valid criteria for the clinical diagnosis of cardiogenic embolism is a major problem in both patient care and research. The aim of this study was to identify features on the initial computed tomogram of the brain that discriminate between patient groups with and without a cardiac source of embolism. To gain insight into the neuroradiological features relevant to the diagnosis of cardiac embolic stroke, we studied the initial computed tomogram of the 1,267 patients with ischemic stroke and such a scan in the National Institute of Neurological Disorders and Stroke (NINDS) Stroke Data Bank. METHODS: We analyzed the initial computed tomographic data from 1,267 patients with ischemic stroke in the NINDS Stroke Data Bank. Based solely on the presence of cardiac sources of embolism, we defined groups with high (n = 244), medium (n = 165), and low (n = 858) risk for cardiogenic embolism and compared the features on the initial computed tomogram among these three groups. RESULTS: Patients in the high-risk group were significantly more likely (p < 0.001) to have infarcts involving one half lobe or larger or infarcts involving both superficial and deep structures than patients in the medium- or low-risk groups. In contrast, deep small infarcts had a negative association (p = 0.004) with the presence of a cardiac source of embolism. There was no significant trend across risk groups in the percent with hemorrhagic infarction, regardless of whether patients with anticoagulant use at the time of the stroke were excluded. CONCLUSION: Although some features of the initial computed tomogram had highly significant associations with the presence of a cardiac source of embolism, the predictive value of these features for an embolic source was low.

Cerebral Infarction↗
PubMed1992

Mechanisms in lacunar infarction.

BACKGROUND AND PURPOSE: Lacunes are thought to occur in patients with hypertension or diabetes mellitus as a result of small-vessel disease. This study evaluated the importance of other stroke mechanisms in a population of patients with lacunar infarction. METHODS: We evaluated 108 consecutive patients with a lacune in the lenticulostriate distribution for other stroke risk factors such as carotid and cardiac disease. RESULTS: Hypertension was present in 68% of the patients and diabetes mellitus in 37%; both occurred in 28% and neither occurred in 23%. Noninvasive carotid studies identified atherosclerotic plaque as a possible embolic source in 23%. By previously established criteria, 18% were at high risk for cardioembolism. Of those with hypertension or diabetes mellitus, 36% were at risk for a carotid or cardiac embolus. Of those without hypertension or diabetes mellitus, 32% had a possible carotid or cardiac etiology. CONCLUSIONS: The high incidence of carotid and cardiac disease in those with and without hypertension or diabetes mellitus suggests the importance of other stroke mechanisms in this population. Patients with lacunar infarction should therefore be evaluated for other causes of stroke that may be treatable.

Aged↗
PubMed1992

Infarcts with a cardiac source of embolism in the NINDS Stroke Data Bank: neurologic examination.

To gain insight into neurologic signs relevant to the diagnosis of cardiogenic embolism, we analyzed data from 1,290 patients with cerebral infarcts in the NINDS Stroke Data Bank. Based solely on the presence of potential cardiac sources of embolism, we divided patients into groups of high (N = 250), medium (N = 167), and low (N = 873) risk of a cardiogenic mechanism for their stroke. Diminished level of consciousness was highly associated with the presence of a cardiac source of embolism. Of the four primarily cortical deficits assessed, three (visual field abnormalities, neglect, and aphasia) showed a highly significant graded relationship to the cardiac risk groups. For the fourth cortical deficit (other nonlanguage cognitive functions), this relationship did not attain statistical significance. Conversely, hemiparesis without sensory or cortical deficits had a strong inverse association to the presence of a cardiac source of embolism. This inverse association was weaker for sensorimotor strokes and nonexistent for pure sensory strokes. Although some neurologic findings had highly significant associations with the presence of a cardiac source of embolism, their predictive value for an embolic source was low.

Cerebral Infarction↗
PubMed1992

Aortic plaque in patients with brain ischemia: diagnosis by transesophageal echocardiography.

We evaluated 183 patients with brain ischemia for an embolic source, using transesophageal echocardiography with extensive imaging of the thoracic aorta. There were mobile, frond-like projections of aortic plaque in seven (4%) patients. The plaque originated on a wide base on the posterior aspect of the ascending aorta at its junction with the transverse arch in six patients, and on the aortic root in one. The acute event was a cerebral infarction in five patients, and a transient ischemic attack in two. This type of aortic plaque could be a previously underdiagnosed source of cerebral embolism that is now easily visualized by transesophageal echocardiography.

Aorta, Thoracic↗
PubMed1991

Intracerebral hemorrhage: external validation and extension of a model for prediction of 30-day survival.

We report validation of a previously reported logistic regression model for predicting 30-day survival after supratentorial intracerebral hemorrhage using independent, prospectively collected data. The original model, using initial Glasgow Coma Scale score, hemorrhage size, and pulse pressure, accounted for mortality or survival at 30 days in 92% of patients in the Pilot Stroke Data Bank with a sensitivity of 0.84 and a specificity of 0.96. For external validation, the model was used to predict 30-day status for each patient in the Main Phase Stroke Data Bank for whom complete risk factor information was available. Overall, 90% of patients' outcomes were correctly predicted with a sensitivity of 0.85 and a specificity of 0.92. Two factors not collected in the Pilot Stroke Data Bank, hyperglycemia and intraventricular hemorrhage extension, were assessed to determine if they provided additional predictive information on 30-day mortality. Intraventricular hemorrhage extension contributed significant predictive information in a logistic regression, whereas hyperglycemia did not. The resulting four-factor model with an interaction term (intraventricular hemorrhage extension and Glasgow Coma Scale score) correctly classified the survival status of 94% of patients at 30 days. A more general outcome, death or failure to achieve a "good" Activities of Daily Living Score by one year, was analyzed with respect to the same four factors. The resulting model correctly classified 95% of the patients in the cohort.

Blood Glucose↗
PubMed1991

The design and automated testing of an expert system for the differential diagnosis of acute stroke.

Stroke is the third leading cause of death in the United States and a major source of morbidity. [1] Recent studies have shown a potential use for thrombolytic agents in the treatment of ischemic stroke (IS) but these agents are contraindicated in intracerebral hemorrhage (ICH). A computed tomographic scan is used to distinguish between these two stroke types prior to the use of thrombolytic agents, but may not be readily obtainable. Decision making aids such as algorithms developed at Guy's Hospital and Strong Memorial Hospital have been designed in an attempt to make this distinction on clinical grounds. We have constructed computerized medical decision-making (CMD) systems based upon these algorithms and compared their performance to a system we developed with the use of National Stroke Data Bank data. Relevant medical data for each of 337 patient cases in the Mount Sinai Hospital Stroke Data Bank were presented to each of the CMD systems. In consideration of the clinical task of using thrombolytic agents, we attempted to maximize the positive predictive value (PPV) for ischemic stroke. The CMD systems based upon the Guy's Hospital and Mount Sinai algorithms produced PPV's of 95% and 94% with sensitivities of 77% and 78% respectively compared to a PPV of 93% and sensitivity of 56% with the Strong Memorial CMD system. The Mount Sinai CMD system was judged more efficacious than the Guy's Hospital system in that it required less clinical information that could be more easily obtained to arrive at similar results.

Acute Disease↗
PubMed1990

Infarcts with a cardiac source of embolism in the NINCDS Stroke Data Bank: historical features.

To gain insight into the historical features relevant to the diagnosis of cardiac embolic strokes, we studied the 1,290 patients with cerebral infarcts in the NINCDS Stroke Data Bank. Based solely on the presence of cardiac sources of embolism, we divided the patients into groups of high (n = 250), medium (n = 166), and low (n = 874) risk of a cardiogenic mechanism for their stroke. There was a highly significant graded relationship between increasing risk of a cardiac source and a history, or presence of, systemic embolism, abrupt onset, and diminished level of consciousness at onset. These clinical features may be useful for assessing the likelihood of a cardiac embolic mechanism in patients with cerebral infarcts.

Cerebral Infarction↗
PubMed1988

Prediction of intracerebral hemorrhage survival.

The Pilot Stroke Data Bank obtained information on 94 patients with intracerebral hemorrhage. These data were used to identify factors predictive of 30-day outcome from among 85 demographic, historical, clinical, and laboratory variables generally available to clinicians on the day of admission. The 9 univariate factors statistically associated with outcome were Glasgow Coma Scale score, systolic blood pressure, pulse pressure, horizontal and vertical gaze palsies, severity of weakness, presence of brainstem-cerebellar deficits, interval stroke course, and parenchymal hemorrhage size. Beginning with these factors, a step-down variable selection procedure was used to derive a logistic regression model, containing only Glasgow Coma Scale score, pulse pressure, and hemorrhage size, that could be used to categorize correctly 92% of the patients as alive or dead at 30 days after onset.

Cerebral Hemorrhage↗
PubMed1984

Intracranial metastases in the initial staging of bronchogenic carcinoma.

We evaluated the effectiveness of neurologic examination, electroencephalography (EEG), and computed tomography (CT) in the initial staging of patients with nonsmall cell carcinoma. Eight of 66 patients had evidence of intracranial metastases. Three of these had no other metastases and would otherwise have been surgical candidates. Thus, thorough investigation for evidence of intracranial metastases is warranted at the time of initial staging. The CT proved to be more effective than clinical evaluation or EEG, alone or in combination, in detecting intracranial metastases. The CT screening of patients prior to curative resection should increase the success rate for such procedures by eliminating patients with preexisting metastases.

Brain Neoplasms↗
PubMedDate not supplied

Feasibility of physician-developed expert systems.

The authors developed an experimental domain-independent "expert system generator" intended for direct use by physicians. They then undertook a four-year study to determine whether physicians could use such a system effectively. During this period they taught the use of the expert system generator to 70 medical students, who utilized it to build two small medical expert systems. At the conclusion of the course, students were examined on decision-making concepts and completed anonymous questionnaires. Performance scores, a composite of test and project grades, were calculated for each student. There was no significant association between previous computer experience and performance score. Thirty-two of 47 students responding felt the expert system generator was easy to use; 15 felt it was of moderate difficulty. Forty-three of 47 thought it a useful teaching aid. These data support the conclusion that physicians can learn to use domain-independent software to implement medical expert systems directly, without a knowledge engineer as an intermediary.

Artificial Intelligence↗