Segmentation of cerebral MRI scans using a partial volume model, shading correction, and an anatomical prior

2001 ◽  
Author(s):  
Aljaz Noe ◽  
Stanislav Kovacic ◽  
James C. Gee
Keyword(s):  
Partial Volume ◽  
Volume Model ◽  
Cerebral Mri ◽  
Mri Scans

Abstract 2568: Cerebral Infarcts in Blacks vs Whites: the Southall and Brent REvisited (SABRE) Multi-ethnic Cohort Study

Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
Dean Shibata ◽  
Therese Tillin ◽  
Norman Beauchamp ◽  
John Heasman ◽  
Wadyslaw Gedroyc ◽  
...  
Keyword(s):  
Risk Factors ◽  
Cardiovascular Health ◽  
African Descent ◽  
Health Study ◽  
Cardiovascular Health Study ◽  
Stroke Mortality ◽  
Black African ◽  
Cerebral Mri ◽  
Mri Scans

Introduction: Stroke mortality is doubled in people of Black African descent compared with Whites, but factors responsible for this excess are unclear. We wished to compare infarct like lesions (ILL) on MRI by ethnicity and the role of risk factors. Methods: SABRE is a UK community based multi-ethnic cohort of men and women aged 40-69 years at baseline (1988-1990), and 58-86 years at follow up (2008-2011). At follow up, a questionnaire was completed and investigations performed including resting and ambulatory BP, anthropometry, and bloods for glucose and lipids. Cerebral MRI scans were scored for infarcts independently by two readers according to the Cardiovascular Health Study protocol. Results: Of 2346 Whites, 684 attended follow up, and 590 completed cerebral MRI. Of 801 Blacks (first generation migrants of Black African descent to the UK), 232 attended clinic and 207 completed MRI. Mortality loss was greater in Whites (605, 25%) than Blacks (121, 15%)(p<0.0001), although stroke was more likely the underlying cause in Blacks (23, 19%), than Whites (43, 7%)(p<0.0001) . Baseline systolic/diastolic BP was similarly higher in Blacks than Whites in attendees (8/5 mmHg), non-responders (7/6 mm Hg), and those who died (8/5 mmHg). At follow up stroke risk factors were adverse in Blacks, apart from smoking ( table ). Prevalence of ILL was similar by ethnicity, not differing when those <65 years were analysed separately, or when those with stroke/TIA history were excluded. Associations between ILL and risk factors did not differ by ethnicity. But prescribed treatment in those with elevated clinic BP (≥140 mmHg systolic, or ≥90 mmHg diastolic) was 83% in Blacks, 63% in Whites (p<0.0001). Further, in those with an ILL, 95% of Blacks, and 69% (p<0.0001) of Whites were on treatment. Conclusion: Equivalence of ILL rates in Blacks and Whites was unanticipated, given the greater stroke mortality in Blacks. Mitigating against selective mortality as the explanation of our findings is the similar ethnic differential in baseline BP in survivors and non-survivors, the lower overall mortality in Blacks, and overall small numbers of stroke deaths. A more likely explanation is that better targeted more aggressive treatment is now occurring in Blacks than Whites, reducing their potential burden of ILL.

Randomized clinical trial comparing a rivaroxaban-based with an antiplatelet-based strategy for cerebral embolization after TAVR (EARTH TAVR)-a magnetic resonance imaging substudy of the GALILEO trial

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
G.M Froehlich ◽  
V Falk ◽  
M Endres ◽  
V Stangl ◽  
J Woehrle ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Acetylsalicylic Acid ◽  
Funding Source ◽  
Resonance Imaging ◽  
Cerebral Lesions ◽  
Once Daily ◽  
Cerebral Mri ◽  
Cerebral Embolization ◽  
Mri Scans

Abstract Background Cerebral embolization in patients after Transcatheter Aortic Valve Replacement (TAVR) represents a serious complication, that was related to impaired bioprosthetic leaflet motion and new-onset atrial fibrillation (AFib). Purpose Hereafter we present the first randomized study comparing the effect of an anticoagulation plus antiplatelet with a dual antiplatelet antithrombotic treatment in patients after TAVR on cerebral embolizations as assessed by serial cerebral magnetic resonance imaging (MRI). Methods The Evaluation of Cerebral Thrombembolism After TAVR (EARTH - TAVR) study was conducted as an investigator initiated substudy of the multicenter, randomized, GALILEO study. After successful TAVR, patients without indication for chronic anticoagulation were randomly assigned to rivaroxaban 10mg plus acetylsalicylic acid 75–100mg once-daily or clopidogrel 75mg plus acetylsalicylic acid 75–100mg once-daily. Cerebral MRI scans were performed pre-TAVR as a baseline, post-TAVR (within 24–48 hours after TAVR) and 90 days after TAVR. The MRI protocol included diffusion-weighted (DWI) and fluid-attenuated inversion recovery (FLAIR) imaging. Cerebral embolic lesions were evaluated by an independent cerebral MRI core lab. The primary outcome measure of this study was the occurrence and extent of cerebral embolizations as measured by total volume of new ischaemic cerebral lesions. Results 36 patients were enrolled in the EARTH and the GALILEO study. The DWI MRI scans revealed an increase of cerebral lesions and volume post-TAVR by a median of 4.75 (95% NBCI 2.1–8.9) and 0.26cm3 (95% NBCI 0.11–0.59). On FLAIR imaging, lesion number and volume increased by a median of 3 (95% NBCI 1.5–6) and 0.1 cm3 (95% NBCI 0.04–0.31). At the 90 days MRI scan, there was no statistically significant change in cerebral lesions, if compared to the post-TAVR scan, irrespective of the treatment arm. Conclusion Thromboembolic events occur largely in the periinterventional phase post TAVR. Thereafter, the risk for additional cerebral embolization is low. An additional rivaroxaban therapy beyond antiplatelet inhibition did not impact on cerebral thromboembolism. Funding Acknowledgement Type of funding source: Private company. Main funding source(s): Bayer Pharmaceuticals

Effects of cerebral magnetic resonance imaging in outpatients on observed incidence of intracranial tumors and patient survival: a national observational study

2014 ◽  
Vol 120 (4) ◽  
pp. 827-832 ◽  
Author(s):  
Ole Solheim ◽  
Magne Torsteinsen ◽  
Tom Børge Johannesen ◽  
Asgeir Store Jakola
Keyword(s):  
Overall Survival ◽  
Brain Tumor ◽  
Observational Study ◽  
Incidence Rates ◽  
Intracranial Tumors ◽  
Cerebral Mri ◽  
Mri Scans ◽  
Per Capita ◽  
Adjusted Incidence ◽  
Age And Sex

Object It is assumed that the observed increase in brain tumor incidence may at least partially be explained by increased use of MRI. However, to date no direct estimate of this effect is available. The authors undertook this registry-based study to examine whether regional frequencies of cerebral MRI use correlate to regional incidence rates of intracranial tumors and survival of patients with these lesions. Methods The authors used Norwegian national population registries from January 2002 through December 2007 to conduct this observational study. They obtained information on outpatient MRI scans in Norwegian counties and examined whether the annual regional rates of cerebral MRI scans correlated to regional age- and sex-adjusted brain tumor incidence rates. They also explored whether differences in cerebral MRI use were associated with survival and examined time trends in the study period. Results Approximately 50,000 cerebral MRI scans are carried out annually in outpatient settings in Norway, and 6363 primary intracranial tumors were diagnosed in Norway during the study period. There was an overall positive correlation between the annual number of cerebral MRI scans per 100,000 capita and age- and sex-adjusted incidence rates of intracranial tumors in the various Norwegian counties (Spearman's rho = 0.35, p < 0.001). In a linear model, an increase in 1 MRI per 100,000 capita per year results in a 0.004 (95% CI 0.002–0.006) increase in diagnosed intracranial tumors per 100,000 capita per year (p < 0.001). Subgroup analysis showed a correlation between MRI use and the annual age- and sex-adjusted incidence rates of extraaxial tumors (p = 0.04, Spearman's rho = 0.28) but not intraaxial tumors (p = 0.394). Overall survival for unselected patients with intracranial tumors is longer with increasing number of cerebral MRI scans per capita in the county of residence at the time of the diagnosis (log rank, p = 0.029). However, after adjustment for year of diagnosis and catchment region of the Norwegian neurosurgical centers, the association between MRI scans per capita and overall survival was no longer statistically significant (p = 0.076). Conclusions Presumably due to the incidental discovery of benign extraaxial tumors, regional differences in the use of cerebral MRI in outpatients affect observed incidence rates of intracranial tumors.

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