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Biomedical subjects

John N Fink

Publications and source records attributed to John N Fink.

7 recordsLinked to original sources
PubMed2005

Insular cortex infarction in acute middle cerebral artery territory stroke: predictor of stroke severity and vascular lesion.

BACKGROUND: Insula infarction is an early computed tomographic sign of middle cerebral artery (MCA) territory stroke and may affect cardiovascular autonomic function. OBJECTIVE: To determine insula involvement in MCA territory infarction and its relationship with infarcts in the remainder of the MCA territory, stroke severity, and clinically relevant cardiovascular conditions. DESIGN: Case series (August 1, 1997, to June 30, 2000). SETTING: Academic stroke center. PATIENTS: A total of 150 consecutive patients with nonlacunar MCA territory stroke who underwent magnetic resonance imaging within 48 hours of stroke onset. MAIN OUTCOME MEASURES: Association of insula infarction with the National Institutes of Health Stroke Scale (NIHSS) score, location of vascular occlusion, and cardiovascular events. RESULTS: Insular lesions were present in 72 patients (48%); 34 (23%) had major insular lesions and 38 (25%) had minor lesions. Insula infarction was associated with lenticulostriate territory infarction (46% vs 14%; P<.001), more than one third of MCA territory infarction (35% vs 3%; P<.001), higher NIHSS score (13.5 vs 6; P<.001), and proximal vascular occlusion detected on magnetic resonance angiography. These associations were strongest for patients with major insular lesions. Clinically significant new arrhythmia was present in 15 of 72 with insula infarction (13 atrial fibrillations) and 4 of 78 without (P = .06). Insula infarction was associated with lower diastolic blood pressure at admission but was not associated with pulse rate, QTc interval, myocardial infarction, or sudden death. CONCLUSIONS: The insular cortex is involved in almost half of patients with nonlacunar ischemic MCA territory strokes. Major insula involvement is associated with large MCA territory infarcts, proximal MCA occlusions, and greater stroke severity. Insula infarction was not a predictor of clinically significant acute cardiovascular events during hospital stay in our patients.

Adult↗
PubMed2003

Cerebrovascular cases.

Five cases are presented illustrating some of the investigative and therapeutic dilemmas faced when treating patients with cerebrovascular disease in the outpatient clinic. The results of some recent major randomized controlled trials are applied to assist the decision-making process for individual patients. The investigation and management of patients with minor stroke or transient ischemic attack, and symptomatic or asymptomatic carotid stenosis are discussed. Issues raised include the role of angiography versus noninvasive imaging, carotid endarterectomy versus carotid stenting, and how to apply new evidence regarding antihypertensive and lipid-lowering therapy to patient management. The role of thrombolysis for acute stroke is discussed, and the work-up of a patient with attacks of dizziness and a patient with atypical headache are also presented.

Acute Disease↗
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

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↗
PubMed2002

Mastoid air sinus abnormalities associated with lateral venous sinus thrombosis: cause or consequence?

BACKGROUND: Mastoiditis is a known cause of lateral venous sinus thrombosis (LST). We have encountered patients with LST associated with mastoid abnormality on MRI without any clinical signs of infection; the significance of these abnormalities is uncertain. This study examines the relationship of LST and mastoid air sinus abnormalities systematically. SUMMARY OF REPORT: We performed a retrospective clinical and radiological review of a series of 26 patients with cerebral venous thrombosis. Mastoid abnormalities were detected ipsilateral to 9 of 23 thrombosed lateral sinuses (39%) and 0 of 29 unaffected lateral sinuses (P<0.001). No patient had clinical evidence of mastoiditis. Eight of 9 patients with mastoid abnormalities were treated without antibiotics; all made uneventful clinical recoveries. Repeated MRI in 1 patient revealed reversal of the mastoid changes. CONCLUSIONS: The mastoid changes observed are likely to be due to venous congestion as a consequence of LST, not mastoiditis.

Adolescent↗