Biomedical subjects

Wade S Smith

Publications and source records attributed to Wade S Smith.

24 records · Page 2Linked to original sources

PubMed2004

Continuous bleeding from a basilar terminus aneurysm imaged with CT angiography and conventional angiography.

We report a case of fatal subarachnoid hemorrhage from nontraumatic rupture of an aneurysm at the basilar terminus in which both computed tomography angiography and conventional angiography showed evidence of active bleeding. The time period from initial ictus to CT angiography was 30-50 minutes and to conventional angiography was 120-140 minutes. This case illustrates that aneurysmal bleeding is not necessarily as brief as a few seconds and can last up to 30 to 50 minutes and perhaps longer. Continued bleeding from an intracranial aneurysm is a rare event that can be recognized using computed tomography angiography and likely indicates a poor prognosis.

Adult↗

PubMed2004

Dynamic perfusion CT: optimizing the temporal resolution and contrast volume for calculation of perfusion CT parameters in stroke patients.

BACKGROUND AND PURPOSE: Numerous parameters are involved in dynamic perfusion CT (PCT). We assessed the influence of the temporal sampling rate and the volume of contrast material. METHODS: Sixty patients with ischemic hemispheric stroke lasting > or = 12 hours underwent PCT. Groups of 15 patients each received 30, 40, 50, or 60 mL of contrast agent. Regional cerebral blood volume (rCBV), regional cerebral blood flow (rCBF), mean transit time (MTT), and time-to-peak (TTP) maps were calculated for temporal sampling intervals of 0.5, 1, 2, 3, 4, 5, and 6 seconds. Results were statistically compared. Signal-to-noise ratios (SNRs), duration of arterial entrance to venous exit, and radiation dose were also assessed. RESULTS: Increasing temporal sampling intervals lead to significant overestimation of rCBV, rCBF, and TTP and significant underestimation of MTT compared with values for an interval of 1 second. Maximal allowable intervals to avoid these effects were 2, 3, 3, and 4 seconds for 30, 40, 50, and 60-mL boluses, respectively. Venous exit of contrast material occurred in 97.5% of patients after 36, 42, 42, and 48 seconds, respectively, for the four volumes. SNRs did not differ with volume. The effective radiation dose varied between 0.852 and 1.867 mSv, depending on the protocol. The cine mode with two 40-mL boluses and the toggling-table technique with one 60-mL bolus had the lowest doses. CONCLUSION: Temporal sampling intervals greater than 1 second can be used without altering the quantitative accuracy of PCT. Increased sampling intervals reduce the radiation dose and may allow for increased spatial coverage.

Aged↗

PubMed2003

Simultanagnosia through the eyes of an artist.

An 87-year-old artist experienced a top-of-the-basilar-artery embolic stroke secondary to atrial fibrillation and manifested a visual agnosia. Prior to her stroke, she painted scenes solely from memory. During her stroke recovery, her serial drawings and paintings revealed selective attention to the left lower quadrant, with important aspects of the whole image "clipped," as if missing from her internal representation of the whole object. Years later, her artistic abilities returned with only minor differences from those prior to her stroke.

Aged↗

PubMed2003

Factors influencing outcome and treatment effect in PROACT II.

BACKGROUND AND PURPOSE: The PROACT II study demonstrated a significant benefit from treatment with intra-arterial pro-urokinase (r-proUK) in patients with middle cerebral artery occlusion treated within 6 hours of stroke onset. The purpose of the current study was to examine baseline factors to determine predictors of good outcome and response to treatment. METHODS: We selected from the baseline clinical, radiologic, and angiographic data variables that considered possibly related to outcome. A univariate analysis was performed to examine the association between these baseline factors and good outcome, defined as a modified Rankin scale score <or=2. A multivariate model then selected the most important variables independently influencing prognosis. A risk score for each patient was constructed on the basis of the patient's individual values for each independent variable. Patients were stratified into risk quartiles based on their risk scores, and an odds ratio for each risk quartile was calculated. The treatment effects of each quartile were compared. RESULTS: In the univariate analysis, screening National Institutes of Health stroke scale (NIHSS) score and age were strongly associated with good outcome. The multivariate model selected age, NIHSS score, and CT hypodensity as the most important prognostic variables. Dividing patients into quartiles based on risk scores achieved a uniform gradient of probability of good outcomes. A trend toward benefit of r-proUK treatment was seen in all risk quartiles, and no differential treatment effect was observed across risk groups. CONCLUSIONS: There was no evidence of differential effect of r-proUK across subgroups of patients stratified by risk.

Adult↗

PubMed2003

Safety and feasibility of a CT protocol for acute stroke: combined CT, CT angiography, and CT perfusion imaging in 53 consecutive patients.

By combining non-contrast-enhanced CT imaging, CT perfusion imaging, and cranial-to-chest CT angiography (CTA), the entire cerebrovascular axis can be imaged during acute stroke. To our knowledge, the safety and feasibility of this technique have not been previously reported. In a consecutive series of 53 patients with suspected acute stroke, renal failure was not observed. Median imaging time was 27 minutes (range, 9-67 minutes). Image quality was degraded by motion in 1.3% of vessels studied. Dynamic CT perfusion data were successfully obtained in 52 patients (98% of patients). High-speed, multisection, helical CT scanners allow rapid, safe imaging of the entire neurovascular axis in patients with acute stroke by use of combined CT imaging, CT perfusion imaging, and CTA.

Acute Disease↗

PubMed2002

Angioplasty for intracranial symptomatic vertebrobasilar ischemia.

OBJECTIVE: Although anterior circulation disease has both medical and surgical treatment options, management of vertebrobasilar disease has predominantly had only medical options. Some patients remain symptomatic despite medical treatment, and angioplasty has been demonstrated to relieve critical stenoses. However, the elative safety and effectiveness of medical and surgical treatments is not clearly known. This report reviews the clinical characteristics, indications, and procedural risks of intracranial angioplasty in a series of patients with symptomatic posterior circulation ischemia. METHODS: All patients undergoing angioplasty for critical intracranial vertebral or basilar artery stenosis at the University of California at San Francisco Medical Center between June 1986 and July 1999 were included in a retrospective record review. Clinical features and procedural complications were recorded. RESULTS: Angioplasty was performed on 25 vessel lesions in 25 patients in whom medical therapy had failed. The patients ranged in age from 50 to 87 years. Of the 25 stenoses, 10 were intracranial vertebral, 9 vertebrobasilar junction, and 6 basilar in location. Angioplasty was effective in reducing the degree of stenosis by more than 40% in all 25 vessels. The overall risk of stroke or death was 28%, and the risk of disabling stroke or death was 16%. CONCLUSION: Intracranial posterior circulation angioplasty is effective in the reduction of stenosis and can be performed with relative safety. Angioplasty can be considered as a treatment option in patients with recurrent ischemic symptoms despite medical therapy.

Aged↗