33 results on '"Grunder L"'
Search Results
2. Spine MRI in Spontaneous Intracranial Hypotension for CSF Leak Detection: Nonsuperiority of Intrathecal Gadolinium to Heavily T2-Weighted Fat-Saturated Sequences
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Dobrocky, T., primary, Winklehner, A., additional, Breiding, P.S., additional, Grunder, L., additional, Peschi, G., additional, Häni, L., additional, Mosimann, P.J., additional, Branca, M., additional, Kaesmacher, J., additional, Mordasini, P., additional, Raabe, A., additional, Ulrich, C.T., additional, Beck, J., additional, Gralla, J., additional, and Piechowiak, E.I., additional
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- 2020
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3. Predicting spinal CSF leaks in intracranial hypotension – a scoring system based on brain MRI findings
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Dobrocky, T, Breiding, P, Grunder, L, Mosimann, P, Mordasini, P, Fung, C, Raabe, A, Ulrich, C, Gralla, J, Beck, J, and Piechowiak, EI
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ddc: 610 ,610 Medical sciences ,Medicine - Abstract
Objective: Various signs may be observed on brain magnetic resonance imaging (MRI) in patients with spontaneous intracranial hypotension (SIH). However, the lack of a classification system integrating these findings limits decision making in clinical practice. The objective was to assess the likelihood[for full text, please go to the a.m. URL], 70. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), Joint Meeting mit der Skandinavischen Gesellschaft für Neurochirurgie
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- 2019
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4. Highway Traffic Contributions to Air Pollution
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Grunder, L. J., primary
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- 1953
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5. West Coast Diesel Smoke And Odor Problems
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Grunder, L. J., primary
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- 1949
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6. War Developments of the Oil Industry In Austria and Roumania
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Grunder, L. J., primary
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- 1946
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7. Weshalb ausländische Jugendliche besonders grosse Probleme haben, eine Lehrstelle zu finden
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Christian Imdorf, Laboratoire d'économie et de sociologie du travail (LEST), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), H-U. Grunder, L. von Mandach, Laboratoire d'Economie et de Sociologie du Travail (LEST), and UMR 7317, LEST
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[SHS.SOCIO]Humanities and Social Sciences/Sociology ,[SHS.SOCIO] Humanities and Social Sciences/Sociology ,qualification - Published
- 2007
8. Susceptibility vessel sign, a predictor of long-term outcome in patients with stroke treated with mechanical thrombectomy.
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Beyeler M, Rea E, Weber L, Belachew NF, Barvulsky Aleman E, Kielkopf M, Kurmann CC, Grunder L, Piechowiak EII, Meinel TR, Heldner MR, Seiffge D, Pilgram-Pastor S, Dobrocky T, Pabst T, Berger MD, Jung S, Arnold M, Gralla J, Fischer U, Kaesmacher J, and Mujanovic A
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Background: The absence of the susceptibility vessel sign (SVS) in patients treated with mechanical thrombectomy (MT) is associated with poor radiological and clinical outcomes after 3 months. Underlying conditions, such as cancer, are assumed to influence SVS status and could potentially impact the long-term outcome. We aimed to assess SVS status as an independent predictor of long-term outcomes in MT-treated patients., Methods: SVS status was retrospectively determined in consecutive MT-treated patients at a comprehensive stroke center between 2010 and 2018. Predictors of long-term mortality and poor functional outcome (modified Rankin Scale (mRS) ≥3) up to 8 years were identified using multivariable Cox and logistic regression, respectively., Results: Of the 558 patients included, SVS was absent in 13% (n=71) and present in 87% (n=487) on baseline imaging. Patients without SVS were more likely to have active cancer (P = 0.003) and diabetes mellitus (P < 0.001) at the time of stroke. The median long-term follow-up time was 1058 days (IQR 533-1671 days). After adjustment for active cancer and diabetes mellitus, among others, the absence of SVS was associated with long-term mortality (adjusted HR (aHR) 2.11, 95% CI 1.35 to 3.29) and poor functional outcome in the long term (adjusted OR (aOR) 2.90, 95% CI 1.29 to 6.55)., Conclusion: MT-treated patients without SVS have higher long-term mortality rates and poorer long-term functional outcome. It appears that this association cannot be explained by comorbidities alone, and further studies are warranted., Competing Interests: Competing interests: MB reports research support from the Kurt und Senta Hermann-Stiftung. JK reports grants from the Swiss Academy of Medical Sciences/Bangerter Foundation, Swiss Stroke Society, and Clinical Trials Unit Bern during the conduct of the study. UF reports grants during the conduct of the study from Medtronic, Stryker, and CSL Behring, unrelated to the submitted work. JG is a global principal investigator of STAR (Solitaire FR Thrombectomy for Acute Revascularisation), Clinical Event Committee member of the PROMISE study (Prospective, Multicenter, Observational, Single-Arm European Registry on the ACE Reperfusion Catheters and the Penumbra System in the Treatment of Acute Ischemic Stroke; Penumbra), and a principal investigator and consultant for the SWIFT DIRECT study (Solitaire With the Intention for Thrombectomy Plus Intravenous tPA Versus DIRECT Solitaire Stent-Retriever Thrombectomy in Acute Anterior Circulation Stroke; Medtronic) and receives Swiss National Science Foundation grants for magnetic resonance imaging in stroke. MA reports personal fees from Bayer, Bristol-Myers Squibb, Medtronic, Amgen, Daiichi Sankyo, Nestlé Health Sciences, Boehringer Ingelheim, and Covidien during the conduct of the study. TRM reports research support from the Bangerter Rhyner Foundation, Swiss National Foundation, and the Swiss Heart Foundation. SJ reports grants from the Swiss National Science Foundation and the Swiss Heart Foundation. EIIP reports grants from the Swiss National Science Foundation. MRH reports grants from Swiss National Science Foundation, SITEM Research Support Funds and Swiss Heart Foundation, not directly related to this manuscript., (© Author(s) (or their employer(s)) 2023. No commercial re-use. See rights and permissions. Published by BMJ.)
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- 2023
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9. Intra-Arterial Thrombolysis is Associated with Delayed Reperfusion of Remaining Vessel Occlusions following Incomplete Thrombectomy.
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Mujanovic A, Kurmann CC, Serrallach BL, Dobrocky T, Meinel TR, Windecker D, Grunder L, Beyeler M, Seiffge DJ, Pilgram-Pastor S, Arnold M, Piechowiak EI, Gralla J, Fischer U, and Kaesmacher J
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- Humans, Middle Aged, Aged, Aged, 80 and over, Treatment Outcome, Thrombectomy methods, Fibrinolytic Agents therapeutic use, Reperfusion methods, Thrombolytic Therapy, Retrospective Studies, Stroke drug therapy, Stroke surgery, Brain Ischemia therapy
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Background and Purpose: Intra-arterial thrombolytics may be used to treat distal vessel occlusions, which cause incomplete reperfusion following mechanical thrombectomy. Because immediate reperfusion after intra-arterial thrombolytics occurs rarely, the aim of this study was to assess the delayed effect of intra-arterial thrombolytics using follow-up perfusion imaging., Materials and Methods: We included patients from a prospective stroke registry (February 2015 to September 2022) who had undergone mechanical thrombectomy and had incomplete reperfusion (expanded TICI 2a-2c) and available 24 hour perfusion imaging. Perfusion imaging was rated as delayed reperfusion if time-sensitive perfusion maps did not show wedge-shaped delays suggestive of persisting occlusions corresponding to the post-mechanical thrombectomy angiographic deficit. Patients treated with intra-arterial thrombolytics were compared with controls using multivariable logistic regression and inverse probability of treatment weighting matching for baseline differences and factors associated with delayed reperfusion., Results: The median age of the final study population ( n = 459) was 74 years (interquartile range, 63-81 years), and delayed reperfusion occurred in 61% of cases. Patients treated with additional intra-arterial thrombolytics ( n = 40) were younger and had worse expanded TICI scores. After matching was performed, intra-arterial thrombolytics was associated with higher rates of delayed reperfusion (adjusted OR = 2.7; 95% CI, 1.1-6.4) and lower rates of new infarction in the residually hypoperfused territory after mechanical thrombectomy (adjusted OR = 0.3; 95% CI, 0.1-0.7). No difference was found in the rates of functional independence (90-day mRS, 0-2; adjusted OR = 1.4; 95% CI, 0.4-4.1)., Conclusions: Rescue intra-arterial thrombolytics is associated with delayed reperfusion of remaining vessel occlusions following incomplete mechanical thrombectomy. The value of intra-arterial thrombolytics as a potential therapy for incomplete reperfusions after mechanical thrombectomy should be assessed in the setting of randomized controlled trials., (© 2023 by American Journal of Neuroradiology.)
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- 2023
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10. Prediction of delayed reperfusion in patients with incomplete reperfusion following thrombectomy.
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Mujanovic A, Brigger R, Kurmann CC, Ng F, Branca M, Dobrocky T, Meinel TR, Windecker D, Almiri W, Grunder L, Beyeler M, Seiffge DJ, Pilgram-Pastor S, Arnold M, Piechowiak EI, Campbell B, Gralla J, Fischer U, and Kaesmacher J
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- Humans, Female, Aged, Male, Thrombectomy, Cerebral Infarction, Reperfusion, Disease Progression, Stroke surgery
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Background: The clinical course of patients with incomplete reperfusion after thrombectomy, defined as an expanded Thrombolysis in Cerebral Infarction (eTICI) score of 2a-2c, is heterogeneous. Patients showing delayed reperfusion (DR) have good clinical outcomes, almost comparable to patients with ad-hoc TICI3 reperfusion. We aimed to develop and internally validate a model that predicts DR occurrence in order to inform physicians about the likelihood of a benign natural disease progression., Patients and Methods: Single-center registry analysis including all consecutive, study-eligible patients admitted between 02/2015 and 12/2021. Preliminary variable selection for the prediction of DR was performed using bootstrapped stepwise backward logistic regression. Interval validation was performed with bootstrapping and the final model was developed using a random forests classification algorithm. Model performance metrics are reported with discrimination, calibration, and clinical decision curves. Primary outcome was concordance statistics as a measure of goodness of fit for the occurrence of DR., Results: A total of 477 patients (48.8% female, mean age 74 years) were included, of whom 279 (58.5%) showed DR on 24 follow-up. The model's discriminative ability for predicting DR was adequate (C-statistics 0.79 [95% CI: 0.72-0.85]). Variables with strongest association with DR were: atrial fibrillation (aOR 2.06 [95% CI: 1.23-3.49]), Intervention-To-Follow-Up time (aOR 1.06 [95% CI: 1.03-1.10]), eTICI score (aOR 3.49 [95% CI: 2.64-4.73]), and collateral status (aOR 1.33 [95% CI: 1.06-1.68]). At a risk threshold of R = 30%, use of the prediction model could potentially reduce the number of additional attempts in one out of four patients who will have spontaneous DR, without missing any patients who do not show spontaneous DR on follow-up., Conclusions: The model presented here shows fair predictive accuracy for estimating chances of DR after incomplete thrombectomy. This may inform treating physicians on the chances of a favorable natural disease progression if no further reperfusion attempts are made.
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- 2023
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11. Absence of susceptibility vessel sign and hyperdense vessel sign in patients with cancer-related stroke.
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Beyeler M, Grunder L, Göcmen J, Steinauer F, Belachew NF, Kielkopf M, Clénin L, Mueller M, Silimon N, Kurmann C, Meinel T, Bücke P, Seiffge D, Dobrocky T, Piechowiak EI, Pilgram-Pastor S, Mattle HP, Navi BB, Arnold M, Fischer U, Pabst T, Gralla J, Berger MD, Jung S, and Kaesmacher J
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Background and Aim: Identification of paraneoplastic hypercoagulability in stroke patients helps to guide investigations and prevent stroke recurrence. A previous study demonstrated an association between the absence of the susceptibility vessel sign (SVS) on brain MRI and active cancer in patients treated with mechanical thrombectomy. The present study aimed to confirm this finding and assess an association between the absence of the hyperdense vessel sign (HVS) on head CT and active cancer in all stroke patients., Methods: SVS and HVS status on baseline imaging were retrospectively assessed in all consecutive stroke patients treated at a comprehensive stroke center between 2015 and 2020. Active cancer, known at the time of stroke or diagnosed within 1 year after stroke (occult cancer), was identified. Adjusted odds ratios (aOR) and their 95% confidence interval (CI) for the association between the thrombus imaging characteristics and cancer were calculated using multivariable logistic regression., Results: Of the 2,256 patients with thrombus imaging characteristics available at baseline, 161 had an active cancer (7.1%), of which 36 were occult at the time of index stroke (1.6% of the total). The absence of SVS was associated with active cancer (aOR 3.14, 95% CI 1.45-6.80). No significance was reached for the subgroup of occult cancer (aOR 3.20, 95% CI 0.73-13.94). No association was found between the absence of HVS and active cancer (aOR 1.07, 95% CI 0.54-2.11)., Conclusion: The absence of SVS but not HVS could help to identify paraneoplastic hypercoagulability in stroke patients with active cancer and guide patient care., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Beyeler, Grunder, Göcmen, Steinauer, Belachew, Kielkopf, Clénin, Mueller, Silimon, Kurmann, Meinel, Bücke, Seiffge, Dobrocky, Piechowiak, Pilgram-Pastor, Mattle, Navi, Arnold, Fischer, Pabst, Gralla, Berger, Jung and Kaesmacher.)
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- 2023
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12. Association of Intravenous Thrombolysis with Delayed Reperfusion After Incomplete Mechanical Thrombectomy.
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Mujanovic A, Kammer C, Kurmann CC, Grunder L, Beyeler M, Lang MF, Piechowiak EI, Meinel TR, Jung S, Almiri W, Pilgram-Pastor S, Hoffmann A, Seiffge DJ, Heldner MR, Dobrocky T, Mordasini P, Arnold M, Gralla J, Fischer U, and Kaesmacher J
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- Humans, Female, Aged, Male, Fibrinolytic Agents therapeutic use, Thrombolytic Therapy, Thrombectomy, Retrospective Studies, Treatment Outcome, Reperfusion, Cerebral Infarction drug therapy, Stroke diagnostic imaging, Stroke drug therapy, Brain Ischemia therapy, Mechanical Thrombolysis
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Purpose: Treatment of distal vessel occlusions causing incomplete reperfusion after mechanical thrombectomy (MT) is debated. We hypothesized that pretreatment with intravenous thrombolysis (IVT) may facilitate delayed reperfusion (DR) of residual vessel occlusions causing incomplete reperfusion after MT., Methods: Retrospective analysis of patients with incomplete reperfusion after MT, defined as extended thrombolysis in cerebral infarction (eTICI) 2a-2c, and available perfusion follow-up imaging at 24 ± 12 h after MT. DR was defined as absence of any perfusion deficit on time-sensitive perfusion maps, indicating the absence of any residual occlusion. The association of IVT with the occurrence of DR was evaluated using a logistic regression analysis adjusted for confounders. Sensitivity analyses based on IVT timing (time between IVT start and the occurrence incomplete reperfusion following MT) were performed., Results: In 368 included patients (median age 73.7 years, 51.1% female), DR occurred in 225 (61.1%). Atrial fibrillation, higher eTICI grade, better collateral status and longer intervention-to-follow-up time were all associated with DR. IVT did not show an association with the occurrence of DR (aOR 0.80, 95% CI 0.44-1.46, even in time-sensitive strata, aOR 2.28 [95% CI 0.65-9.23] and aOR 1.53 [95% CI 0.52-4.73] for IVT to incomplete reperfusion following MT timing <80 and <100 min, respectively)., Conclusion: A DR occurred in 60% of patients with incomplete MT at ~24 h and did not seem to occur more often in patients receiving pretreatment IVT. Further research on potential associations of IVT and DR after MT is required., (© 2022. The Author(s).)
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- 2023
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13. Importance of Delayed Reperfusions in Patients With Incomplete Thrombectomy.
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Mujanovic A, Jungi N, Kurmann CC, Dobrocky T, Meinel TR, Almiri W, Grunder L, Beyeler M, Lang MF, Jung S, Klail T, Hoffmann A, Seiffge DJ, Heldner MR, Pilgram-Pastor S, Mordasini P, Arnold M, Piechowiak EI, Gralla J, Fischer U, and Kaesmacher J
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- Humans, Female, Male, Retrospective Studies, Treatment Outcome, Thrombectomy methods, Reperfusion, Cerebral Infarction diagnostic imaging, Cerebral Infarction surgery, Brain Ischemia therapy, Stroke diagnostic imaging, Stroke surgery, Endovascular Procedures
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Background: There is paucity of data regarding the effects of delayed reperfusion (DR) on clinical outcomes in patients with incomplete reperfusion following mechanical thrombectomy. We hypothesized that DR has a strong association with clinical outcome in patients with incomplete reperfusion after mechanical thrombectomy (expanded Thrombolysis in Cerebral Infarction, 2a-2c)., Methods: Single-institution's stroke registry retrospective analysis of patients admitted from February 2015 to December 2020. DR was defined as the absence of any perfusion delay on ≈24-hour contrast-enhanced follow-up perfusion imaging, whereas persistent perfusion deficit denotes a perfusion delay corresponding to the catheter angiographic deficit directly after the intervention. The association of perfusion outcome (DR versus persistent perfusion deficit) with the occurrence of new infarcts and 90-day functional independence (modified Rankin Scale score 0-2) was evaluated using logistic regression analyses. Comparison of predictive accuracy was evaluated by calculating area under the curve for models with and without perfusion outcome., Results: In 566 patients (mean age 74, 49.6% female), new infarcts in the incomplete reperfusion areas were less common in DR versus persistent perfusion deficit patients (small punctiform: 17.1% versus 25%, large confluent: 7.9% versus 63.2%; P =0.001). After adjustment for confounders, DR was a strong predictor of functional independence (adjusted odds ratio, 2.37 [95% CI 1.34-4.23]). There was a significant improvement in predictive accuracy of functional independence when perfusion outcome was added to expanded Thrombolysis in Cerebral Infarction alone (area under the curve 0.57 versus 0.62, P =0.01)., Conclusions: Occurrence of DR is closely associated with tissue outcome and functional independence. DR may be an independent prognostic parameter, suggesting it as a potential outcome surrogate for medical rescue therapies.
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- 2022
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14. Absence of Susceptibility Vessel Sign in Patients With Malignancy-Related Acute Ischemic Stroke Treated With Mechanical Thrombectomy.
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Beyeler M, Belachew NF, Kielkopf M, Aleman EB, León Betancourt AX, Genceviciute K, Kurmann C, Grunder L, Birner B, Meinel TR, Scutelnic A, Bücke P, Seiffge DJ, Dobrocky T, Piechowiak EI, Pilgram-Pastor S, Mattle HP, Mordasini P, Arnold M, Fischer U, Pabst T, Gralla J, Berger MD, Jung S, and Kaesmacher J
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Background and Purpose: Clots rich in platelets and fibrin retrieved from patients with acute ischemic stroke (AIS) have been shown to be independently associated with the absence of the susceptibility vessel sign (SVS) on MRI and active malignancy. This study analyzed the association of SVS and the presence of active malignancy in patients with AIS who underwent mechanical thrombectomy (MT)., Methods: This single-center, retrospective, and cross-sectional study included consecutive patients with AIS with admission MRI treated with MT between January 2010 and December 2018. SVS status was evaluated on susceptibility-weighted imaging. Adjusted odds ratios (aORs) were calculated to determine the association between absent SVS and the presence of active or occult malignancy. The performance of predictive models incorporating and excluding SVS status was compared using areas under the receiver operating characteristics curve (auROC)., Results: Of 577 patients with AIS with assessable SVS status, 40 (6.9%) had a documented active malignancy and 72 (12.5%) showed no SVS. The absence of SVS was associated with active malignancy (aOR 4.85, 95% CI 1.94-12.11) or occult malignancy (aOR 11.42, 95% CI 2.36-55.20). The auROC of predictive models, including demographics and common malignancy biomarkers, was higher but not significant (0.85 vs. 0.81, p = 0.07) when SVS status was included., Conclusion: Absence of SVS on admission MRI of patients with AIS undergoing MT is associated with malignancy, regardless of whether known or occult. Therefore, the SVS might be helpful in detecting paraneoplastic coagulation disorders and occult malignancy in patients with AIS., Competing Interests: TM reports research support from the Bangerter Rhyner Foundation, Swiss National Foundation, and the Swiss Heart Foundation. HM reports personal consulting fees outside of this study from Servier, Bayer, Medtronic, Stryker and Cerenovus. PM reports receipt of research support from Siemens, Cerenovus, iSchmaview, Medtronic, Stryker, the Swiss Heart Foundation and the Swiss National Foundation, receipt of consultant fees paid to the institution from Medtronic, Cerenovus, Phenox and Microvention during the conduct of the study, unrelated to the submitted work. MA reports personal fees from Bayer, Bristol-Myers Squibb, Medtronic, Amgen, Daiichi Sankyo, Nestlé Health Sciences, Boehringer Ingelheim, and Covidien during the conduct of the study. UF reports grants during the conduct of the study from Medtronic, Stryker, and CSL Behring, unrelated to the submitted work. JK reports grants from the Swiss Academy of Medical Sciences/Bangerter Foundation, Swiss Stroke Society, and Clinical Trials Unit Bern during the conduct of the study. SJ reports grants from the Swiss National Science Foundation and the Swiss Heart Foundation. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Beyeler, Belachew, Kielkopf, Aleman, León Betancourt, Genceviciute, Kurmann, Grunder, Birner, Meinel, Scutelnic, Bücke, Seiffge, Dobrocky, Piechowiak, Pilgram-Pastor, Mattle, Mordasini, Arnold, Fischer, Pabst, Gralla, Berger, Jung and Kaesmacher.)
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- 2022
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15. Association of reperfusion success and emboli in new territories with long term mortality after mechanical thrombectomy.
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Beyeler M, Weber L, Kurmann CC, Piechowiak EII, Mosimann PJ, Zibold F, Meinel TR, Branca M, Goeldlin M, Pilgram-Pastor SM, Grunder L, Arnold M, Seiffge D, Meier R, Heldner MR, Dobrocky T, Mordasini P, Gralla J, Fischer U, and Kaesmacher J
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- Humans, Reperfusion, Retrospective Studies, Thrombectomy adverse effects, Treatment Outcome, Brain Ischemia therapy, Embolism etiology, Stroke etiology, Stroke surgery
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Background: The degree of reperfusion is the most important modifiable predictor of 3 month functional outcome and mortality in ischemic stroke patients treated with mechanical thrombectomy. Whether the beneficial effect of reperfusion also leads to a reduction in long term mortality is unknown., Methods: Patients undergoing mechanical thrombectomy between January 2010 and December 2018 were included. The post-thrombectomy degree of reperfusion and emboli in new territories were core laboratory adjudicated. Reperfusion was evaluated according to the expanded Thrombolysis in Cerebral Infarction (eTICI) scale. Vital status was obtained from the Swiss population register. Adjusted hazard ratios (aHRs) using time split Cox regression models were calculated. Subgroup analyses were performed in patients with borderline indications., Results: Our study included 1264 patients (median follow-up per patient 2.5 years). Patients with successful reperfusion had longer survival times, attributable to a lower hazard of death within 0-90 days and for >90 days to 2 years (aHR 0.34, 95% CI 0.26 to 0.46; aHR 0.37, 95% CI 0.22 to 0.62). This association was homogeneous across all predefined subgroups (p for interaction >0.05). Among patients with successful reperfusion, a significant difference in the hazard of death was observed between eTICI2b50 and eTICI3 (aHR 0.51, 95% CI 0.33 to 0.79). Emboli in new territories were present in 5% of patients, and were associated with increased mortality (aHR 2.3, 95% CI 1.11 to 4.86)., Conclusion: Successful, and ideally complete, reperfusion without emboli in new territories is associated with a reduction in long term mortality in patients treated with mechanical thrombectomy, and this was evident across several subgroups., Competing Interests: Competing interests: UF reports grants during the conduct of the study from Medtronic, Stryker, and CSL Behring, unrelated to the submitted work. JG is a global principal investigator of STAR (Solitaire FR Thrombectomy for Acute Revascularisation), Clinical Event Committee member of the PROMISE study (Prospective, Multicenter, Observational, Single-Arm European Registry on the ACE Reperfusion Catheters and the Penumbra System in the Treatment of Acute Ischemic Stroke; Penumbra), and a principal investigator and consultant for the SWIFT DIRECT study (Solitaire With the Intention for Thrombectomy Plus Intravenous tPA Versus DIRECT Solitaire Stent-Retriever Thrombectomy in Acute Anterior Circulation Stroke; Medtronic) and receives Swiss National Science Foundation grants for magnetic resonance imaging in stroke. JK reports grants from the Swiss Academy of Medical Sciences/Bangerter Foundation, Swiss Stroke Society, and Clinical Trials Unit Bern during the conduct of the study. MA reports personal fees from Bayer, Bristol-Myers Squibb, Medtronic, Amgen, Daiichi Sankyo, Nestlé Health Sciences, Boehringer Ingelheim, and Covidien during the conduct of the study. TRM reports research support from the Bangerter Rhyner Foundation, Swiss National Foundation, and the Swiss Heart Foundation. MRH reports research support from the Bangerter Foundation, scientific advisory board honoraria from Amgen, and personal fees from Bayer., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)
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- 2022
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16. Chronic Covert Brain Infarctions and White Matter Hyperintensities in Patients With Stroke, Transient Ischemic Attack, and Stroke Mimic.
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Epstein A, Schilter M, Vynckier J, Kaesmacher J, Mujanovic A, Scutelnic A, Beyeler M, Belachew NF, Grunder L, Arnold M, Seiffge DJ, Jung S, Fischer U, and Meinel TR
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- Aged, Brain Infarction, Cohort Studies, Female, Humans, Magnetic Resonance Imaging, Male, Prospective Studies, Risk Factors, Ischemic Attack, Transient complications, Ischemic Attack, Transient diagnosis, Ischemic Attack, Transient epidemiology, Ischemic Stroke, Leukoaraiosis, Stroke complications, Stroke diagnosis, Stroke epidemiology, White Matter diagnostic imaging, White Matter pathology
- Abstract
Background This study was conducted to compare frequencies of chronic brain infarctions (CBIs) and white matter hyperintensities (WMHs) as well as their associations with established early recurrence risk scores in patients with transient ischemic attack (TIA) and stroke mimics compared with ischemic stroke. Methods and Results Single-center cohort study including consecutive patients with TIA, stroke mimics, and acute ischemic stroke, with available magnetic resonance imaging from January 2015 to December 2017. Blinded raters adjudicated WMH (age-related white matter changes score) and CBI according to established definitions. A total of 2112 patients (median [Q1-Q3] age 71 [59-80] years, 43% women, National Institutes of Health Stroke Scale score of 2 [1-7], 80% ischemic stroke, 18% TIA, 2% stroke mimics) were included. While CBIs were present in only 10% of patients with stroke mimic, they were detected in 28% of TIAs and 38% of ischemic strokes ( P <0.001). WMHs were less pronounced (0, 0-1) in patients with stroke mimic, but there was no difference between TIA (1, 1-2) and ischemic stroke (0, 1-2) patients. CBIs (adjusted odds ratio, 0.3; 95% CI, 0.1-0.9) were associated with a lower rate of stroke mimic as the final diagnosis, while WMHs were not (adjusted odds ratio per point, 1.3; 95% CI, 0.7-2.2). WMH (β per point, 0.4; 95% CI, 0.3-0.6) and presence of CBI (β, 0.6; 95% CI, 0.3-0.9) were associated with a higher cardiovascular risk profile according to the ABCD3-I score. The accuracy of prediction was good for high-risk TIA (cross-validated area under the receiver operating characteristic curve, 0.89; 95% CI, 0.79-0.93) on the basis of brain imaging, age, and sex. Conclusions CBI and WMH differ between patients with stroke mimic and patients with TIA/ischemic stroke and are closely associated with established recurrence risk scores. Prospective studies need to clarify whether including brain frailty markers may contribute to the refinement of current management algorithms and risk stratifications.
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- 2022
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17. Phenotypes of Chronic Covert Brain Infarction in Patients With First-Ever Ischemic Stroke: A Cohort Study.
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Vynckier J, Kaesmacher J, Wardlaw JM, Roten L, Beyeler M, Belachew NF, Grunder L, Seiffge DJ, Jung S, Gralla J, Dobrocky T, Heldner MR, Prange U, Goeldlin MB, Arnold M, Fischer U, and Meinel TR
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- Aged, Aged, 80 and over, Atrial Fibrillation complications, Cerebellar Diseases diagnostic imaging, Cerebellar Diseases etiology, Cerebral Cortex diagnostic imaging, Cerebral Infarction etiology, Cohort Studies, Female, Gray Matter diagnostic imaging, Humans, Intracranial Embolism complications, Ischemic Stroke complications, Magnetic Resonance Imaging, Male, Middle Aged, Phenotype, Risk Factors, Tomography, X-Ray Computed, White Matter diagnostic imaging, Cerebral Infarction diagnostic imaging, Ischemic Stroke diagnostic imaging
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Background and Purpose: The aim of this study was to assess the rate of chronic covert brain infarctions (CBIs) in patients with acute ischemic stroke (AIS) and to describe their phenotypes and diagnostic value., Methods: This is a single-center cohort study including 1546 consecutive patients with first-ever AIS on magnetic resonance imaging imaging from January 2015 to December 2017. The main study outcomes were CBI phenotypes, their relative frequencies, location, and association with vascular risk factors., Results: Any CBI was present in 574/1546 (37% [95% CI, 35%-40%]) of patients with a total of 950 CBI lesions. The most frequent locations of CBI were cerebellar in 295/950 (31%), subcortical supratentorial in 292/950 (31%), and cortical in 213/950 (24%). CBI phenotypes included lacunes (49%), combined gray and white matter lesions (30%), gray matter lesions (13%), and large subcortical infarcts (7%). Vascular risk profile and white matter hyperintensities severity (19% if no white matter hyperintensity, 63% in severe white matter hyperintensity, P <0.001) were associated with presence of any CBI. Atrial fibrillation was associated with cortical lesions (adjusted odds ratio, 2.032 [95% CI, 1.041-3.967]). Median National Institutes of Health Stroke Scale scores on admission were higher in patients with an embolic CBI phenotype (median National Institutes of Health Stroke Scale, 5 [2-10], P =0.025)., Conclusions: CBIs were present in more than a third of patients with first AIS. Their location and phenotypes as determined by MRI were different from previous studies using computed tomography imaging. Among patients suffering from AIS, those with additional CBI represent a vascular high-risk subgroup and the association of different phenotypes of CBIs with differing risk factor profiles potentially points toward discriminative AIS etiologies.
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- 2022
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18. Early Neurologic Deterioration in Lacunar Stroke: Clinical and Imaging Predictors and Association With Long-term Outcome.
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Vynckier J, Maamari B, Grunder L, Goeldlin MB, Meinel TR, Kaesmacher J, Hakim A, Arnold M, Gralla J, Seiffge DJ, and Fischer U
- Abstract
Background and Objectives: To determine the rate and predictors of early neurologic deterioration (END) in patients with lacunar strokes and its implications for management and outcome., Methods: We enrolled consecutive patients with MRI-defined lacunar stroke who presented within 12 hours after symptom onset from a prospective stroke database (2015-2019). END was defined as any persisting increase in NIH Stroke Scale (NIHSS) score of ≥2 points within 24 hours after admission and favorable outcome as modified Rankin Scale (mRS) score of 0 to 2 at 90 days. We assessed the association of END with clinical and imaging variables, acute treatment, and outcome using multivariable regression, calculating adjusted odds ratios (aORs)., Results: Sixty-one of 365 (16.7%) patients with acute lacunar stroke (median age 71.8 years, 39.5% female, median NIHSS score on admission 3) had END. Lower NIHSS score on admission (per point, aOR 0.81, p = 0.006), capsular warning syndrome (aOR 7.00, p < 0.001), ventral pontine infarct (aOR 3.49, p = 0.008), and hypoperfusion lesion on imaging (aOR 2.13, p = 0.026) were associated with END. Acute dual antiplatelet therapy was associated with reduced risk of END (aOR 0.10, p = 0.04). Patients with END had less favorable outcome at 90 days (aOR 0.13 p < 0.001), but IV thrombolysis (IVT) was associated with favorable outcome at 90 days (aOR 3.95, p = 0.002)., Discussion: One in 6 patients with lacunar stroke has END, and patients at high risk of END can be identified with radiologic and clinical variables. Targeted therapeutic trials for this population seem justified., Classification of Evidence: This study provides Class II evidence that early neurologic deterioration in patients with acute lacunar stroke predicts poorer functional outcome at 90 days as determined by the mRS., (© 2021 American Academy of Neurology.)
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- 2021
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19. Imaging Neurovascular Uncoupling in Acute Migraine with Aura with Susceptibility Weighted Imaging.
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Kellner-Weldon F, Jossen M, Breiding PS, Grunder L, Schankin C, Scutelnic A, Fischer U, Muri R, Pastore-Wapp M, Wiest R, and El-Koussy M
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- Adolescent, Adult, Aged, Aged, 80 and over, Female, Humans, Magnetic Resonance Imaging, Male, Middle Aged, Young Adult, Cerebral Veins, Epilepsy, Migraine with Aura diagnostic imaging
- Abstract
Purpose: Migraine with aura (MwA) in the emergency setting is common and sometimes difficult to distinguish from mimicking conditions. Susceptibility weighted imaging (SWI), a magnet resonance (MR) technique is sensitive to deoxygenated hemoglobin in cerebral veins and depicts these according to their level of oxygenation. Our study aimed at evaluating the frequency of regions of prominent focal veins (PFV) on SWI in the acute phase., Methods: Between 2011 and 2018 we evaluated symptoms and MR imaging of adult patients with acute MwA attacks (< 5 days after onset of symptoms). Abnormal imaging was visually scored in 12 ROIs on both hemispheres distributed on 3 slices. The score ranged from 0 to 3., Results: In all, 638 patients (436 female) mean age 37.39 years (18-89 ± 14.13) were included. Susceptibility weighted imaging was abnormal in 18.8% of patients. The inferior and posterior medial temporal lobe and the occipital lobe were most often affected. Susceptibility weighted imaging was more likely abnormal when MR was performed within 24 hours with an average around 5 hours after symptom onset. The side of aura symptoms and hemispheric imaging alteration in patients with abnormal SWI was highly significant (p < 0.001)., Conclusion: In the acute episode of MwA, SWI imaging can show a combination of increased deoxygenation. The results may indicate linking PFV to MwA., (© 2020. Springer-Verlag GmbH Germany, part of Springer Nature.)
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- 2021
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20. Bridging May Increase the Risk of Symptomatic Intracranial Hemorrhage in Thrombectomy Patients With Low Alberta Stroke Program Early Computed Tomography Score.
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Kaesmacher J, Meinel TR, Nannoni S, Olivé-Gadea M, Piechowiak EI, Maegerlein C, Goeldlin M, Pierot L, Seiffge DJ, Mendes Pereira V, Heldner MR, Grunder L, Costalat V, Arnold M, Dobrocky T, Gralla J, Mordasini P, and Fischer U
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- Aged, Aged, 80 and over, Cohort Studies, Diffusion Magnetic Resonance Imaging, Female, Humans, Male, Middle Aged, Risk, Stroke mortality, Tissue Plasminogen Activator adverse effects, Tissue Plasminogen Activator therapeutic use, Tomography, X-Ray Computed, Treatment Outcome, Intracranial Hemorrhages etiology, Stroke diagnostic imaging, Stroke therapy, Thrombectomy adverse effects
- Abstract
Background and Purpose: Whether intravenous thrombolysis (IVT) increases the risk for symptomatic intracranial hemorrhage (sICH) in patients treated with mechanical thrombectomy (MT) is a matter of debate. Purpose of this study was to evaluate the extent of early ischemia as a possible factor influencing the risk for sICH after IVT+MT versus direct MT., Methods: An explorative analysis of the BEYOND-SWIFT (Bernese-European Registry for Ischemic Stroke Patients Treated Outside Current Guidelines With Neurothrombectomy Devices Using the SOLITAIRE FR With the Intention for Thrombectomy) multicenter cohort was performed. We hypothesized that the sICH risk between IVT+MT versus direct MT differs across the strata of Alberta Stroke Program Early CT Scores (ASPECTS). For this purpose, all patients with ICA, M1, and M2 vessel occlusions and available noncontrast computed tomography or diffusion-weighed imaging ASPECTS (n=2002) were analyzed. We used logistic regression analysis in subgroups, as well as interaction terms, to address the risk of sICH in IVT+MT versus direct MT patients across the ASPECTS strata., Results: In 2002 patients (median age, 73.7 years; 50.7% women; median National Institutes of Health Stroke Scale score, 16), the overall rate of sICH was 6.5% (95% CI, 5.5%-7.7%). Risk of sICH differed across ASPECTS groups (9-10: 6.3%; 6-8: 5.6% and ≤5 9.8%; P =0.042). With decreasing ASPECTS, the risks of sICH in the IVT+MT versus the direct MT group increased from adjusted odds ratio of 0.61 ([95% CI, 0.24-1.60] ASPECTS 9-10), to 1.72 ([95% CI, 0.69-4.24] ASPECTS 6-8) and 6.31 ([95% CI, 1.87-21.29] ASPECTS ≤5), yielding a positive interaction term (1.91 [95% CI, 1.01-3.63]). Sensitivity analyses regarding diffusion-weighed imaging versus noncontrast computed tomography ASPECTS did not alter the primary observations., Conclusions: The extent of early ischemia may influence relative risks of sICH in IVT+MT versus direct MT patients, with an excess sICH risk in IVT+MT patients with low ASPECTS. If confirmed in post hoc analyses of randomized controlled trial data, IVT may be administered more carefully in patients with low ASPECTS eligible for and with direct access to MT.
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- 2021
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21. Simultaneous lesion and brain segmentation in multiple sclerosis using deep neural networks.
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McKinley R, Wepfer R, Aschwanden F, Grunder L, Muri R, Rummel C, Verma R, Weisstanner C, Reyes M, Salmen A, Chan A, Wagner F, and Wiest R
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- Brain diagnostic imaging, Humans, Image Processing, Computer-Assisted, Magnetic Resonance Imaging, Multiple Sclerosis diagnostic imaging, Neural Networks, Computer, Brain pathology, Multiple Sclerosis pathology
- Abstract
Segmentation of white matter lesions and deep grey matter structures is an important task in the quantification of magnetic resonance imaging in multiple sclerosis. In this paper we explore segmentation solutions based on convolutional neural networks (CNNs) for providing fast, reliable segmentations of lesions and grey-matter structures in multi-modal MR imaging, and the performance of these methods when applied to out-of-centre data. We trained two state-of-the-art fully convolutional CNN architectures on the 2016 MSSEG training dataset, which was annotated by seven independent human raters: a reference implementation of a 3D Unet, and a more recently proposed 3D-to-2D architecture (DeepSCAN). We then retrained those methods on a larger dataset from a single centre, with and without labels for other brain structures. We quantified changes in performance owing to dataset shift, and changes in performance by adding the additional brain-structure labels. We also compared performance with freely available reference methods. Both fully-convolutional CNN methods substantially outperform other approaches in the literature when trained and evaluated in cross-validation on the MSSEG dataset, showing agreement with human raters in the range of human inter-rater variability. Both architectures showed drops in performance when trained on single-centre data and tested on the MSSEG dataset. When trained with the addition of weak anatomical labels derived from Freesurfer, the performance of the 3D Unet degraded, while the performance of the DeepSCAN net improved. Overall, the DeepSCAN network predicting both lesion and anatomical labels was the best-performing network examined.
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- 2021
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22. Findings in susceptibility weighted imaging in pediatric patients with migraine with aura.
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Kellner-Weldon F, Lehmann VF, Breiding PS, Grunder L, Muri R, Pastore-Wapp M, Bigi S, Wiest R, El-Koussy M, and Slavova N
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- Adolescent, Brain pathology, Child, Female, Humans, Magnetic Resonance Imaging methods, Male, Migraine with Aura pathology, Retrospective Studies, Brain blood supply, Brain diagnostic imaging, Migraine with Aura diagnostic imaging
- Abstract
Background: Migraine with aura (MwA) in pediatric patients is clinically frequent. Clinically complex symptoms need to be differentiated to exclude mimicking conditions., Purpose: We hypothesize that MwA in children induces abnormalities readily visible in perfusion time to peak (TTP) maps as well as non-enhanced susceptibility weighted magnetic resonance imaging (SWI)., Materials and Methods: Between 2010 and 2018, we retrospectively evaluated symptoms and imaging of consecutive pediatric patients <18 years with MwA. We visually scored abnormalities on SWI and TTP maps in 12 regions of interest on both hemispheres on three axial slices, as normal, slightly, distinctly or severely abnormal., Results: 99 patients (69.7% female), mean age 14.07 y (±2.8) were included. Focally increased deoxygenation (FID) in SWI was present in 61.6%. FID on SWI was dominant for the left hemisphere (60.7% vs. 31.1%, (p < .001)), and in 8.2% symmetric. Side of aura symptoms and contralateral hemispheric imaging alterations in patients with FID correlated significantly (p = .002.). 61 of 99 patients had perfusion MR and 59% of these patients showed focal increase of TTP. Age correlated significantly with FID in SWI (r = -.248, p = .013) and increase of TTP in perfusion (r = -.252, p = .05). Focal abnormalities correlated significantly between SWI and TTP maps. Brain regions most often abnormal were the temporal superior, occipital and fronto-parietal regions., Conclusions: This study provides confidence in recognizing FID, and linking FID in SWI to acute MwA in pediatric patients. FID phenomenon had a left hemispheric significant dominance, and can be found bilaterally., Competing Interests: Declaration of competing interest Roland Wiest: UNRELATED: Grants/Grants Pending: Swiss National Foundation, Swiss Heart Foundation., (Copyright © 2020 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2020
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23. Spine MRI in Spontaneous Intracranial Hypotension for CSF Leak Detection: Nonsuperiority of Intrathecal Gadolinium to Heavily T2-Weighted Fat-Saturated Sequences.
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Dobrocky T, Winklehner A, Breiding PS, Grunder L, Peschi G, Häni L, Mosimann PJ, Branca M, Kaesmacher J, Mordasini P, Raabe A, Ulrich CT, Beck J, Gralla J, and Piechowiak EI
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- Adult, Aged, Aged, 80 and over, Cerebrospinal Fluid Leak complications, Female, Gadolinium DTPA, Humans, Image Enhancement methods, Intracranial Hypotension etiology, Male, Middle Aged, Myelography methods, Retrospective Studies, Cerebrospinal Fluid Leak diagnostic imaging, Intracranial Hypotension diagnostic imaging, Magnetic Resonance Imaging methods, Spinal Cord diagnostic imaging
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Background and Purpose: Spine MR imaging plays a pivotal role in the diagnostic work-up of spontaneous intracranial hypotension. The aim of this study was to compare the diagnostic accuracy of unenhanced spine MR imaging and intrathecal gadolinium-enhanced spine MR imaging for identification and localization of CSF leaks in patients with spontaneous intracranial hypotension., Materials and Methods: A retrospective study of patients with spontaneous intracranial hypotension examined from February 2013 to October 2017 was conducted. Their spine MR imaging was reviewed by 3 blinded readers for the presence of epidural CSF using 3 different sequences (T2WI, 3D T2WI fat-saturated, T1WI gadolinium). In patients with leaks, the presumed level of the leak was reported., Results: In total, 103 patients with spontaneous intracranial hypotension (63/103 [61%] women; mean age, 50 years) were evaluated. Seventy had a confirmed CSF leak (57/70 [81%] proved intraoperatively), and 33 showed no epidural CSF on multimodal imaging. Intrathecal gadolinium-enhanced spine MR imaging was nonsuperior to unenhanced spine MR imaging for the detection of epidural CSF ( P = .24 and .97). All MR imaging sequences had a low accuracy for leak localization. In all patients, only 1 leakage point was present, albeit multiple suspicious lesions were reported in all sequences (mean, 5.0)., Conclusions: Intrathecal gadolinium-enhanced spine MR imaging does not improve the diagnostic accuracy for the detection of epidural CSF. Thus, it lacks a rationale to be included in the routine spontaneous intracranial hypotension work-up. Heavily T2-weighted images with fat saturation provide high accuracy for the detection of an epidural CSF collection. Low accuracy for leak localization is due to an extensive CSF collection spanning several vertebrae (false localizing sign), lack of temporal resolution, and a multiplicity of suspicious lesions, albeit only a single leakage site is present. Thus, dynamic examination is mandatory before targeted treatment is initiated., (© 2020 by American Journal of Neuroradiology.)
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- 2020
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24. Quantification of cerebral veins in patients with acute migraine with aura: A fully automated quantification algorithm using susceptibility-weighted imaging.
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Breiding PS, Kellner-Weldon F, Grunder L, Scutelnic A, Fischer U, Meinel TR, Slavova N, Gralla J, El-Koussy M, and Denier N
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- Adult, Feasibility Studies, Female, Humans, Male, Middle Aged, Prospective Studies, Retrospective Studies, Young Adult, Algorithms, Cerebral Veins diagnostic imaging, Image Processing, Computer-Assisted, Magnetic Resonance Angiography methods, Migraine with Aura diagnosis
- Abstract
Introduction: Susceptibility weighted imaging (SWI) is a very sensitive technique that often depicts prominent focal veins (PFV) in patients with acute migraine with aura (MwA). Interpretation of visual venous asymmetry (VVA) between brain hemispheres on SWI may help support the clinical diagnosis of MwA. Our goal was to develop an automated algorithm for segmentation and quantification of cerebral veins using SWI., Materials and Methods: Expert readers visually evaluated SWI of patients with acute MwA for VVA. Subsequently a fully automated algorithm based on 3D normalization and 2D imaging processing using SPM and MATLAB image processing software including top-hat transform was used to quantify cerebral veins and to calculate volumetric differences between hemispheres., Results: Fifty patients with MwA were examined with SWI. VVA was present in 20 of 50 patients (40%). In 95% of patients with VVA, the fully automated calculation agreed with the side that visually harboured more PFV. Our algorithm showed a sensitivity of 95%, specificity of 90% and accuracy of 92% for detecting VVA. Patients with VVA had significantly larger vein volume on the hemisphere with more PFV compared to patients without (15.90 ± 5.38 ml vs 11.93 ± 5.31 ml; p = 0.013). The mean difference in venous volume between hemispheres in patients with VVA was larger compared to patients without VVA (16.34 ± 7.76% vs 4.31 ± 3.26% p < 1E-10). The average time between aura onset and SWI correlated negatively with venous volume of the dominant brain hemisphere (r = -0.348; p = 0.038)., Conclusion: A fully automated algorithm can accurately identify and quantify cerebral venous distribution on SWI. Absolute quantification may be useful for the future assessment of patients with suspected diseases, which may be associated with a unilateral abnormal degree of venous oxygenation., Competing Interests: The authors have declared that no competing interests exist.
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- 2020
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25. [Imaging of the peripheral nervous system].
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Grunder L, Guggenberger R, and Wurnig MC
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- Humans, Magnetic Resonance Imaging, Tomography, X-Ray Computed, Ultrasonography, Peripheral Nervous System, Peripheral Nervous System Diseases diagnosis, Peripheral Nervous System Diseases diagnostic imaging
- Abstract
Imaging of the peripheral nervous system Abstract. With the technical advances in imaging achieved in recent years, the significance of radiology in everyday clinical practice has become definitely increased. This also applies to the diagnosis and evaluation of neuropathies. Highly sensitive electrophysiology is increasingly complemented by specific imaging. Therapy-relevant information from imaging includes the localization and cause, but also the distribution pattern of a neuropathy. Neurography helps to increase diagnostic certainty and is an important part in management of patients with neuropathy. In this article we would like to present the possibilities and the value of different imaging modalities including ultrasound (US), computed tomography (CT) and magnetic resonance imaging (MRI).
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- 2020
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26. Automatic detection of lesion load change in Multiple Sclerosis using convolutional neural networks with segmentation confidence.
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McKinley R, Wepfer R, Grunder L, Aschwanden F, Fischer T, Friedli C, Muri R, Rummel C, Verma R, Weisstanner C, Wiestler B, Berger C, Eichinger P, Muhlau M, Reyes M, Salmen A, Chan A, Wiest R, and Wagner F
- Subjects
- Adult, Brain pathology, Humans, Image Interpretation, Computer-Assisted standards, Longitudinal Studies, Magnetic Resonance Imaging standards, Multiple Sclerosis pathology, Neuroimaging standards, Brain diagnostic imaging, Deep Learning standards, Image Interpretation, Computer-Assisted methods, Magnetic Resonance Imaging methods, Multiple Sclerosis diagnostic imaging, Neuroimaging methods
- Abstract
The detection of new or enlarged white-matter lesions is a vital task in the monitoring of patients undergoing disease-modifying treatment for multiple sclerosis. However, the definition of 'new or enlarged' is not fixed, and it is known that lesion-counting is highly subjective, with high degree of inter- and intra-rater variability. Automated methods for lesion quantification, if accurate enough, hold the potential to make the detection of new and enlarged lesions consistent and repeatable. However, the majority of lesion segmentation algorithms are not evaluated for their ability to separate radiologically progressive from radiologically stable patients, despite this being a pressing clinical use-case. In this paper, we explore the ability of a deep learning segmentation classifier to separate stable from progressive patients by lesion volume and lesion count, and find that neither measure provides a good separation. Instead, we propose a method for identifying lesion changes of high certainty, and establish on an internal dataset of longitudinal multiple sclerosis cases that this method is able to separate progressive from stable time-points with a very high level of discrimination (AUC = 0.999), while changes in lesion volume are much less able to perform this separation (AUC = 0.71). Validation of the method on two external datasets confirms that the method is able to generalize beyond the setting in which it was trained, achieving an accuracies of 75 % and 85 % in separating stable and progressive time-points., (Copyright © 2019. Published by Elsevier Inc.)
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- 2020
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27. Assessing Spinal Cerebrospinal Fluid Leaks in Spontaneous Intracranial Hypotension With a Scoring System Based on Brain Magnetic Resonance Imaging Findings.
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Dobrocky T, Grunder L, Breiding PS, Branca M, Limacher A, Mosimann PJ, Mordasini P, Zibold F, Haeni L, Jesse CM, Fung C, Raabe A, Ulrich CT, Gralla J, Beck J, and Piechowiak EI
- Subjects
- Adolescent, Adult, Aged, Case-Control Studies, Cranial Sinuses diagnostic imaging, Dura Mater diagnostic imaging, Female, Humans, Logistic Models, Magnetic Resonance Imaging, Male, Middle Aged, Multivariate Analysis, Myelography, Subdural Space diagnostic imaging, Tomography, X-Ray Computed, Young Adult, Brain diagnostic imaging, Cerebrospinal Fluid Leak diagnostic imaging, Intracranial Hypotension diagnostic imaging
- Abstract
Importance: Various signs may be observed on brain magnetic resonance imaging (MRI) in patients with spontaneous intracranial hypotension (SIH). However, the lack of a classification system integrating these findings limits decision making in clinical practice., Objective: To develop a probability score based on the most relevant brain MRI findings to assess the likelihood of an underlying spinal cerebrospinal fluid (CSF) leak in patients with SIH., Design, Setting, and Participants: This case-control study in consecutive patients investigated for SIH was conducted at a single hospital department from February 2013 to October 2017. Patients with missing brain MRI data were excluded. Three blinded readers retrospectively reviewed the brain MRI scans of patients with SIH and a spinal CSF leak, patients with orthostatic headache without a CSF leak, and healthy control participants, evaluating 9 quantitative and 7 qualitative signs. A predictive diagnostic score based on multivariable backward logistic regression analysis was then derived. Its performance was validated internally in a prospective cohort of patients who had clinical suspicion for SIH., Main Outcomes and Measures: Likelihood of a spinal CSF leak based on the proposed diagnostic score., Results: A total of 152 participants (101 female [66.4%]; mean [SD] age, 46.1 [14.3] years) were studied. These included 56 with SIH and a spinal CSF leak, 16 with orthostatic headache without a CSF leak, 60 control participants, and 20 patients in the validation cohort. Six imaging findings were included in the final scoring system. Three were weighted as major (2 points each): pachymeningeal enhancement, engorgement of venous sinus, and effacement of the suprasellar cistern of 4.0 mm or less. Three were considered minor (1 point each): subdural fluid collection, effacement of the prepontine cistern of 5.0 mm or less, and mamillopontine distance of 6.5 mm or less. Patients were classified into groups at low, intermediate, or high probability of having a spinal CSF leak, with total scores of 2 points or fewer, 3 to 4 points, and 5 points or more, respectively, on a scale of 9 points. The discriminatory ability of the proposed score could be demonstrated in the validation cohort., Conclusions and Relevance: This 3-tier predictive scoring system is based on the 6 most relevant brain MRI findings and allows assessment of the likelihood (low, intermediate, or high) of a positive spinal imaging result in patients with SIH. It may be useful in identifying patients with SIH who are leak positive and in whom further invasive myelographic examinations are warranted before considering targeted therapy.
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- 2019
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28. Rebound After Fingolimod and a Single Daclizumab Injection in a Patient Retrospectively Diagnosed With NMO Spectrum Disorder-MRI Apparent Diffusion Coefficient Maps in Differential Diagnosis of Demyelinating CNS Disorders.
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Wagner F, Grunder L, Hakim A, Kamber N, Horn MP, Muellner J, Hoepner R, Wiest R, Metz I, Chan A, and Salmen A
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Objective: Differential diagnosis of neuromyelitis optica spectrum disorders (NMOSD) and multiple sclerosis (MS) or mimics can be challenging, especially in patients with atypical presentations and negative serostatus for aquaporin-4 antibodies (AQP4-Ab). This brief research report describes magnetic resonance imaging (MRI) findings focusing on quantitative apparent diffusion coefficient (ADC) histogram analysis as a potential tool to differentiate NMOSD from MS. Methods: Longitudinal MRI data obtained during routine clinical examinations were retrospectively analyzed in a patient with histologically determined cerebral NMOSD, a patient with an acute tumefactive MS lesion, and a patient with ischemic stroke. Histogram analyses of ADC maps were evaluated. Results: A patient diagnosed with MS experienced a severe rebound after fingolimod withdrawal and a single daclizumab injection. Cerebral NMOSD manifestation was confirmed by brain biopsy. However, the patient did not fulfill consensus criteria for NMOSD and was AQP4-Ab negative. Comparison of ADC histogram analyses of this patient with those from a patient with MS and one with ischemic stroke revealed differential ADC characteristics: namely a more pronounced and prolonged ADC leftward shift in inflammatory than in ischemic pathology, even more accentuated in NMOSD versus MS. Conclusion: ADC map histograms and ADC threshold values for different conditions may be useful for differentiation of large inflammatory brain lesions and further studies are merited.
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- 2018
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29. Segmentation of Peripheral Nerves From Magnetic Resonance Neurography: A Fully-Automatic, Deep Learning-Based Approach.
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Balsiger F, Steindel C, Arn M, Wagner B, Grunder L, El-Koussy M, Valenzuela W, Reyes M, and Scheidegger O
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Diagnosis of peripheral neuropathies relies on neurological examinations, electrodiagnostic studies, and since recently magnetic resonance neurography (MRN). The aim of this study was to develop and evaluate a fully-automatic segmentation method of peripheral nerves of the thigh. T2-weighted sequences without fat suppression acquired on a 3 T MR scanner were retrospectively analyzed in 10 healthy volunteers and 42 patients suffering from clinically and electrophysiologically diagnosed sciatic neuropathy. A fully-convolutional neural network was developed to segment the MRN images into peripheral nerve and background tissues. The performance of the method was compared to manual inter-rater segmentation variability. The proposed method yielded Dice coefficients of 0.859 ± 0.061 and 0.719 ± 0.128, Hausdorff distances of 13.9 ± 26.6 and 12.4 ± 12.1 mm, and volumetric similarities of 0.930 ± 0.054 and 0.897 ± 0.109, for the healthy volunteer and patient cohorts, respectively. The complete segmentation process requires less than one second, which is a significant decrease to manual segmentation with an average duration of 19 ± 8 min. Considering cross-sectional area or signal intensity of the segmented nerves, focal and extended lesions might be detected. Such analyses could be used as biomarker for lesion burden, or serve as volume of interest for further quantitative MRN techniques. We demonstrated that fully-automatic segmentation of healthy and neuropathic sciatic nerves can be performed from standard MRN images with good accuracy and in a clinically feasible time.
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- 2018
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30. Adipogenic and antiapoptotic protein levels in human adipose stromal cells after weight loss.
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Aubin D, Gagnon A, Grunder L, Dent R, Allen M, and Sorisky A
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- Adipose Tissue blood supply, Adult, Aged, Aged, 80 and over, Body Constitution, Female, Humans, Male, Middle Aged, Neuronal Apoptosis-Inhibitory Protein, Neurons chemistry, Receptors, Cytoplasmic and Nuclear analysis, Stromal Cells chemistry, Transcription Factors analysis, Adipose Tissue chemistry, CCAAT-Enhancer-Binding Protein-alpha analysis, Nerve Tissue Proteins analysis, Weight Loss physiology
- Abstract
Objective: Obesity is a major risk factor for type 2 diabetes and cardiovascular disease. However, current strategies to achieve sustained weight loss are often unsuccessful. Fat reaccumulation might be favored by enhanced adipose cell differentiation or survival in the postreduced state., Research Methods and Procedures: We measured adipogenic and apoptotic protein expression in subcutaneous abdominal adipose stromal-vascular cells from 10 obese patients (7 women and 3 men) that were obtained before and after a 16% weight loss in a medically supervised weight loss program., Results: After weight loss, protein expression was 2.4-fold higher (p < 0.005) for p42 C/CAAT enhancer binding protein alpha, but there was no change for peroxisome proliferator-activated receptor gamma1; both of these are adipogenic regulators. For neuronal apoptosis inhibitory protein, a protein associated with adipose cell apoptotic resistance, there was a rise of 1.7-fold (p < 0.02)., Discussion: Alterations in C/CAAT enhancer binding protein alpha and neuronal apoptosis inhibitory protein expression occurred in human adipose stromal-vascular cells after weight loss in a pilot study of 10 patients. It will be important for future studies to directly examine whether the adipogenic and antiapoptotic capacity of these cells is changed after weight loss.
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- 2004
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31. Comparison of human abdominal subcutaneous versus omental preadipocyte differentiation in primary culture.
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Shahparaki A, Grunder L, and Sorisky A
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- Adipocytes enzymology, Cell Differentiation, Cells, Cultured, Cytosol enzymology, Female, Glycerolphosphate Dehydrogenase metabolism, Humans, Male, Stem Cells enzymology, Abdomen, Adipocytes cytology, Omentum, Skin, Stem Cells cytology
- Abstract
Excess intra-abdominal fat is associated with a higher risk for type 2 diabetes mellitus and cardiovascular disease, yet little is known about what influences regional adipose tissue accumulation. Adipocytes arise from specialized fibroblast-like preadipocytes within the adipose tissue stromal-vascular compartment. The aim of our study was to determine if there are variations in preadipocyte differentiation between abdominal subcutaneous (SC) and omental (OM) preadipocytes. Abdominal SC and OM preadipocytes were isolated from adipose tissue obtained from 18 subjects (7 men, 11 women), undergoing elective abdominal surgery, by collagenase treatment and filtration/centrifugation. Preadipocytes were placed in culture and then differentiated for 3 weeks in a serum-free medium containing insulin, dexamethasone, isobutylmethylxanthine, and carbaprostacyclin. The cells were then harvested for measurement of cytosolic glycerol phosphate dehydrogenase (GPDH), a marker of terminal differentiation. Data are expressed as a differentiation index (DI), which was the log of the SC/OM ratio of GPDH values for each patient (calculated as 0 for an equivalent SC v OM responses). The mean DI for the group (n = 18) was 0.04, with a 95% confidence interval (CI) of -0.11 to 0.20. The mean DI for men was 0.07 (95% CI, -0.06 to 0.19), and that for women was 0.03 (95% CI, -0.21 to 0.27). This indicates that SC versus OM preadipocyte differentiation responses were not significantly different from each other, either for the group as a whole or when divided by gender. Overall, 8 subjects had a DI favoring SC preadipocyte differentiation, compared to 11 subjects with a DI reflecting greater OM preadipocyte differentiation. There was no correlation of the DI with body mass index or age. Our results indicate that preadipocytes from the abdominal SC adipose tissue depot do not uniformly differentiate more than those from the OM depot., (Copyright 2002, Elsevier Science (USA). All rights reserved.)
- Published
- 2002
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32. Functional TSH receptor in human abdominal preadipocytes and orbital fibroblasts.
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Bell A, Gagnon A, Grunder L, Parikh SJ, Smith TJ, and Sorisky A
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- Abdomen, Abdominal Muscles, Adipocytes drug effects, Animals, CHO Cells, Cells, Cultured, Cricetinae, Fibroblasts drug effects, Humans, Jurkat Cells, Mice, Omentum, Rats, Receptors, Thyrotropin drug effects, Ribosomal Protein S6 Kinases drug effects, Thyroid Gland drug effects, Thyroid Gland metabolism, Thyrotropin pharmacology, Adipocytes metabolism, Fibroblasts metabolism, Receptors, Thyrotropin metabolism, Ribosomal Protein S6 Kinases metabolism
- Abstract
Controversy continues about whether, and to what levels of abundance, thyroid-stimulating hormone receptors (TSHR) are found in human tissues other than the thyroid gland. Restricted expression to the thyroid and orbit would suggest that TSHR represents the target autoantigen in thyroid-associated ophthalmopathy. A more generalized pattern of tissue expression would be inconsistent with TSHR acting as the autoantigen that is solely responsible for selectively targeting the immune system to the orbit. We have detected TSHR mRNA in human abdominal adipose tissue by Northern blot analysis. TSHR protein was also detected, by immunoblotting with two different antibodies, in preadipocytes isolated from human abdominal subcutaneous and omental adipose tissue and in derivative adipocytes differentiated in primary culture. Preadipocytes treated with thyroid-stimulating hormone (TSH) exhibited a sevenfold increase in the activity of p70 S6 kinase, a serine/threonine kinase recently recognized as a downstream target of TSHR in thyroid cells. Activation of p70 S6 kinase by TSH was also observed in orbital fibroblasts. Thus TSHR protein expression is found in fibroblasts from several anatomic locations, suggesting that factors other than site-limited TSHR expression must be involved in restricting the distribution of Graves' disease manifestations. Furthermore, the presence of functional TSHR in preadipocytes raises the possibility of a novel role for TSHR signaling in adipose tissue development.
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- 2000
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33. Rapamycin inhibits human adipocyte differentiation in primary culture.
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Bell A, Grunder L, and Sorisky A
- Subjects
- Adipocytes cytology, Azo Compounds chemistry, Cell Culture Techniques, Cell Differentiation physiology, Cells, Cultured, Coloring Agents chemistry, Female, Glycerolphosphate Dehydrogenase analysis, Humans, Male, Middle Aged, Scintillation Counting, Thymidine chemistry, Adipocytes drug effects, Adipose Tissue cytology, Cell Differentiation drug effects, Immunosuppressive Agents pharmacology, Sirolimus pharmacology
- Abstract
Objective: The immunosuppressant drug rapamycin, has been reported to inhibit 3T3-L1 adipocyte differentiation by interfering with critical postconfluent mitoses that are required early on for successful differentiation of this cell line (clonal expansion phase). In contrast to the murine 3T3-L1 preadipocyte cell line, human preadipocytes in primary culture do not undergo clonal expansion during differentiation. We investigated whether rapamycin could inhibit human adipocyte differentiation., Research Methods and Procedures: The effect of rapamycin on the induction of differentiation of human preadipocytes in primary culture into adipocytes was measured using Oil Red O staining and glycerol phosphate dehydrogenase activity., Results: We have observed that rapamycin severely curtails human adipocyte differentiation of both omental and abdominal subcutaneous preadipocytes (to 14% and 19% of standard differentiation, respectively). The rapamycin-mediated inhibition of human adipocyte differentiation could be reversed in the presence of excess amounts of FK-506, which displaces rapamycin from its intracellular receptor, FKPB12. Measurement of cytosolic protein and [3H]thymidine incorporation into DNA confirmed the absence of proliferation during differentiation of human preadipocytes in primary culture., Discussion: Our data indicate that rapamycin exerts important negative regulatory effects on adipogenesis in human preadipocytes, through a mechanism that does not depend on interruption of clonal expansion.
- Published
- 2000
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