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Jeffrey L Sunshine

Publications and source records attributed to Jeffrey L Sunshine.

8 recordsLinked to original sources
PubMed2006

Model-free parameters from dynamic contrast-enhanced-MRI: sensitivity to EES volume fraction and bolus timing.

PURPOSE: To quantify the unknown relative sensitivities of semiquantitative measures from dynamic contrast-enhanced (DCE) MRI to variations in the volume fraction V(e) of the extravascular extracellular space (EES), and the duration of the contrast injection. MATERIALS AND METHODS: Tissue-uptake curves were simulated across various values of F, PS, V(e), and bolus timings, with and without additive noise and at different image reacquisition rates. From each, the peak of the first derivative (G(peak)), the total uptake after the rapid first phase (CE), and the IAUC were calculated and plotted against F for each experimental condition. Relationships between each measure and the corresponding quantitative measure K(trans) were also examined, particularly for linearity. RESULTS: The highest sensitivity to flow was achieved for shorter bolus timings for G(peak), CE, and IAUC. G(peak) and IAUC were most linearly related to K(trans). The sensitivity to V(e) was lowest for G(peak), followed by IAUC and CE. Long sampling intervals resulted in severe underestimation of G(peak), while IAUC was unaffected provided that the limits of integration were properly applied. G(peak) could not be properly calculated in the presence of noise without a prior smoothing of the acquired curves, while IAUC was again unaffected by noise. CONCLUSION: G(peak) and IAUC are both useful model-free analogs of blood flow (i.e., K(trans)) for pre- and posttreatment comparisons. G(peak) may be the better choice in cases where larger changes in V(e) are likely, but only if sufficient noise reduction and fast image sampling are applied. If V(e) is expected to remain stable, IAUC is superior to G(peak) by virtue of its stability in the face of noise and more reliable estimation over a wider range of sampling rates.

Contrast Media↗
PubMed2005

Thrombolytic therapy of acute ischemic stroke: correlation of angiographic recanalization with clinical outcome.

BACKGROUND AND PURPOSE: The effect of vessel patency, following recombinant tissue plasminogen activator (rtPA) administration, on clinical outcome in acute ischemic stroke (AIS) has been controversial. We studied the effect of recanalization following intraarterial (IA) and intravenous/IA (IV/IA) rtPA on clinical outcome in AIS. METHODS: Recanalization was classified angiographically as complete (as compared with unoccluded vessel, thrombolysis in myocardial infarction classification [TIMI] 3), none (with no change from prethrombolysis, TIMI 0), and partial (when a change in the flow from baseline was noted, TIMI 1-2). Outcomes were symptomatic intracranial hemorrhage (sICH), 90-day modified Rankin scale (< or = 2 as a good outcome), and 3-month mortality. RESULTS: Ninety-six patients had either combined IV/IA (41) or IA (55) rtPA for AIS during a 7-year period. Any recanalization occurred in 69%; 55% of those had a good outcome versus 23% in the rest (Odds ratio = 3.9; 95% confidence interval [CI] = 1.4-11.2; P = .007). Only 24% had complete recanalization; 74% had a good outcome versus 36% in the nonrecanalization group (OR = 5.1; 95% CI = 1.6-16.8; P = .002). When adjusted to time to therapy and vessel occluded, these results lessened but remained significant. The sICH rate with any recanalization was 7.6% versus 13.3% in patients with persistent clot (relative risk (RR) = 0.6; 95% CI = 0.2-2.0; P = .45). Death occurred in 19.7% of those whose vessels recanalized versus 33.3% in the rest (RR = 0.56; 95% = 0.26-1.19; P = .2). CONCLUSION: A total of 24% and 69% of patients had complete and any recanalization, respectively, following endovascular rtPA therapy of AIS. The degree of recanalization was directly related to time to therapy and associated with good clinical outcome without an increase in the rate of adverse effect.

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PubMed2004

Predictors of hyperacute clinical worsening in ischemic stroke patients receiving thrombolytic therapy.

BACKGROUND AND PURPOSE: Although long-term outcome determinants in acute ischemic stroke (AIS) patients have been defined, less is known about those predicting hyperacute worsening after thrombolytic therapy (TT). We investigated predictors of short-term clinical worsening (National Institutes of Health Stroke Scale [NIHSS] change > or =4 within 24 hours of admission). METHODS: We studied 201 AIS patients who received TT within 6 hours of symptom onset. We determined baseline demographics, comorbidities, NIHSS at baseline and at 24 hours after TT, head computed tomography scan before and within 24 hours after TT, and angiographic recanalization in patients treated with intra-arterial (IA) thrombolysis. Significance of relationships was evaluated by t test or Wilcoxon signed rank sum test. Logistic regression model (LRM) was fitted to determine independence of significant variables. RESULTS: Of 201 patients, 13% worsened, 39% improved, and 48% remained unchanged 24 hours after TT. Most patients (72%) received IA thrombolysis. Patients who deteriorated, compared with those who improved, were more likely to have complicating intracranial hemorrhage (ICH; P<0.001), absent recanalization (P=0.026), and higher blood glucose (BG; P=0.049). Hyperglycemia (>150 mg/dL) was greater in patients who worsened even in presence of recanalization (P=0.004, odds ratio [OR] 6.47). LRM showed that adjusted OR for increased risk of bad outcome and mortality for an increase of BG by 50 mg/dL is 1.56 and 1.38, respectively. CONCLUSIONS: Hyperglycemia and ICH are independent predictors of hyperacute worsening in AIS patients receiving TT. Although recanalization is the purpose of IA thrombolysis, its impact on clinical improvement may not be apparent without strict BG control.

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PubMed2002

Endovascular administration after intravenous infusion of thrombolytic agents for the treatment of patients with acute ischemic strokes.

OBJECTIVE: To determine the feasibility of combined intravenous and intra-arterial thrombolytic therapy for acute ischemic strokes and to evaluate its associated risks, using magnetic resonance imaging as a triage tool. Intravenous treatment followed by intra-arterial infusion may increase the rate of recanalization and lead to better clinical results, with reduced frequency of intracranial hemorrhage. METHODS: Our Brain Attack Team evaluated patients who presented within 3 hours after symptom onset. Patients who did not demonstrate improvement and exhibited no evidence of intracranial hemorrhage on head computed tomographic scans were treated with intravenously administered recombinant tissue plasminogen activator (0.6 mg/kg) and underwent emergency magnetic resonance imaging of the head. T2-weighted turbo-gradient and spin echo and echo-planar diffusion- and perfusion-weighted imaging scans were obtained. Patients with evidence of imaging abnormalities indicating acute cortical infarction underwent cerebral angiography. After determination of vessel occlusion, intra-arterially administered urokinase (up to 750,000 units) or intra-arterially administered recombinant tissue plasminogen activator (maximal dose, 0.3 mg/kg) was used to achieve recanalization. RESULTS: We treated 45 patients with this protocol. The mean age was 67 +/- 13 years, and 58% of the patients were women. There was a significant improvement in National Institutes of Health Stroke Scale scores after treatment. There was good correlation between abnormal perfusion-weighted imaging findings and cerebral angiographic findings (complete vessel occlusion). The incidence of symptomatic intracranial hemorrhage was 4.4% in this cohort. Seven patients died in the hospital, and the majority of survivors (77%) experienced good outcomes (Barthel index of >or=95) 3 months after treatment. CONCLUSION: Our data demonstrate that this protocol is feasible and that combined intravenous and intra-arterial thrombolysis to treat acute ischemic strokes is sufficiently safe to warrant further evaluation.

Acute Disease↗
PubMed2002

Response to intra-arterial and combined intravenous and intra-arterial thrombolytic therapy in patients with distal internal carotid artery occlusion.

BACKGROUND AND PURPOSE: The objective of this study was to determine the clinical features, angiographic findings, and response to treatment with thrombolytic therapy in patients with ischemic stroke caused by acute occlusion of the distal internal carotid artery. METHODS: This is a retrospective case series from a prospectively collected stroke database for patients with acute internal carotid occlusion presenting within 6 hours of stroke onset to evaluate safety, feasibility, and response to thrombolytic therapy. The University Hospital-based brain attack database was reviewed over a 5-year period. Demographics, clinical features, stroke mechanisms, severity, imaging findings, type of thrombolysis, treatment responses, mortality, and long-term outcome using modified Rankin Scale and Barthel Index were determined. The short-term outcome was assessed using the National Institutes of Health Stroke Scale (NIHSS). Acute thrombolytic therapy was administered using recombinant tissue plasminogen activator or urokinase given intra-arterially or in combination with intravenous (IV) routes. RESULTS: Two hundred seven patients treated with thrombolysis between 1995 and 2000 were reviewed, and of these, 101 were studied with cerebral angiography. Eighteen patients were identified with acute ischemic stroke and ipsilateral occlusion of the distal internal carotid artery. Time to treatment was the most powerful predictor of response to thrombolytic therapy (P<0.001). The response to therapy also correlated well with the severity of the initial clinical deficit as judged by the NIHSS (P<0.001). There was no difference in recanalization rate, symptomatic hemorrhage, and NIHSS for IV/intra-arterial (IA) versus IA alone (P=NS). Complete angiographic recanalization was accomplished in 80% of those who received combined IV/IA thrombolysis and in 62% of those who received IA therapy (P=NS). Those with distal occlusions extending to the middle and anterior cerebral arteries were the least likely to respond to thrombolysis. Symptomatic intracerebral hemorrhage occurred in 20% of the patients receiving IV/IA therapy, and in 15% of the IA only (P=NS). At 24 hours, the NIHSS dropped by 3 points in the IA group and 4 points in the IV/IA group (P=NS). Mild disability with independence was found in 77% of the survivors at 3-month follow-up. The mortality rate was 50% in this group despite thrombolysis. CONCLUSIONS: Thrombolytic therapy using a combination of IV and IA routes and using the IA-only route may be effective in improving outcome for the patients suffering from occlusion of the distal internal carotid artery. Shorter intervals between onset and treatment seem to be correlated with higher rate of recanalization and improved outcome.

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