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Dive into the research topics where Tomas Dobrocky is active.

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Featured researches published by Tomas Dobrocky.


Journal of NeuroInterventional Surgery | 2017

Thrombectomy of calcified emboli in stroke. Does histology of thrombi influence the effectiveness of thrombectomy

Tomas Dobrocky; Eike Immo Piechowiak; Alessandro Cianfoni; Felix Zibold; Luca Roccatagliata; Pascal J. Mosimann; Simon Jung; Urs Fischer; Pasquale Mordasini; Jan Gralla

Background and purpose Thrombus composition has been postulated to affect the success of endovascular therapy. Calcified clots are composed of large amounts of calcium phosphate which influences their mechanical properties and may serve as a model for testing this hypothesis. The aim of this study was to evaluate the recanalization and complication rates of calcified thromboemboli in patients with acute ischemic stroke who underwent thrombectomy. Material and methods A retrospective analysis was performed of all calcified intracranial thromboemboli in patients suffering an acute ischemic stroke, referred for endovascular therapy at two centers between January 2013 and July 2016. Results Eight patients with a calcified intracranial clot underwent stent retriever thrombectomy (five women; mean age 80 years). Mean clot attenuation was 305 HU (range 150–640 HU). Successful reperfusion defined, as Thrombolysis in Cerebral Infarction grade 2b–3 was achieved in only one patient (12.5%). Two periprocedural adverse events occurred: one peripheral vessel perforation which was coiled and one inadvertent stent retriever detachment due to fracture of the stent retriever wire. Conclusion Stent retriever thrombectomy of calcified thromboemboli seems less effective than with other types of clots. Different mechanical properties of calcified clots may render them stiffer and less accessible for stent retrievers. When faced with a calcified intracranial thromboembolus in clinical practice, a more contained approach may be warranted in view of low recanalization rates, and the potential for periprocedural adverse events.


Stroke | 2017

Direct Mechanical Intervention Versus Bridging Therapy in Stroke Patients Eligible for Intravenous Thrombolysis: A Pooled Analysis of 2 Registries

Sebastian Bellwald; Ralph Weber; Tomas Dobrocky; Hannes Nordmeyer; Simon Jung; Jeffrie Hadisurya; Pasquale Mordasini; Marie-Luise Mono; Christian P. Stracke; Hakan Sarikaya; Corrado Bernasconi; Klaus Berger; Marcel Arnold; René Chapot; Jan Gralla; Urs Fischer

Background and Purpose— Randomized controlled trials have shown that mechanical thrombectomy (MT) plus best medical treatment improves outcome in stroke patients with large-vessel occlusion in the anterior circulation. Whether direct MT is equally effective as bridging thrombolysis (intravenous thrombolysis plus MT) in intravenous thrombolysis eligible patients remains unclear. Methods— We compared clinical and radiological outcomes at 3 months in 249 bridging patients with 111 patients receiving direct MT for large-vessel occlusion anterior circulation stroke from 2 prospective registries (study period Essen: June 2012 to August 2013, Bern February 2009 to August 2014). We matched all patients from the direct MT group who would have qualified for intravenous thrombolysis with controls from the bridging group, using multivariate and propensity score methods. Subgroup analyses for internal carotid artery occlusions were performed. Results— Baseline characteristics did not differ between the direct MT group and bridging cohort, except for higher rates of coronary heart disease (P=0.029) and shorter intervals from onset to endovascular therapy (P<0.001) in the MT group. Functional outcome, mortality, and intracerebral hemorrhage did not differ, neither in univariate nor after multivariate and propensity score matching. However, in patients with internal carotid artery occlusion, mortality in the direct cohort was significantly lower. Conclusions— In this matched-pair analysis, there was no difference in outcome in patients with large-vessel occlusion anterior circulation stroke treated with direct MT compared with those treated with bridging thrombolysis; however, mortality in patients with internal carotid artery occlusion treated with direct MT was significantly lower than after bridging thrombolysis. Randomized trials comparing direct MT with bridging therapy are needed.


American Journal of Roentgenology | 2016

Maximum-Intensity-Projection and Computer-Aided-Detection Algorithms as Stand-Alone Reader Devices in Lung Cancer Screening Using Different Dose Levels and Reconstruction Kernels

Lukas Ebner; Justus E. Roos; Jared D. Christensen; Tomas Dobrocky; Lars Leidolt; Barbara Brela; Verena Carola Obmann; Sonya Joy; Adrian Thomas Huber; Andreas Christe

OBJECTIVE The objective of our study was to evaluate lung nodule detection rates on standard and microdose chest CT with two different computer-aided detection systems (SyngoCT-CAD, VA 20, Siemens Healthcare [CAD1]; Lung CAD, IntelliSpace Portal DX Server, Philips Healthcare [CAD2]) as well as maximum-intensity-projection (MIP) images. We also assessed the impact of different reconstruction kernels. MATERIALS AND METHODS Standard and microdose CT using three reconstruction kernels (i30, i50, i70) was performed with an anthropomorphic chest phantom. We placed 133 ground-glass and 133 solid nodules (diameters of 5 mm, 8 mm, 10 mm, and 12 mm) in 55 phantoms. Four blinded readers evaluated the MIP images; one recorded the results of CAD1 and CAD2. Sensitivities for CAD and MIP nodule detection on standard dose and microdose CT were calculated for each reconstruction kernel. RESULTS Dose for microdose CT was significantly less than that for standard-dose CT (0.1323 mSv vs 1.65 mSv; p < 0.0001). CAD1 delivered superior results compared with CAD2 for standard-dose and microdose CT (p < 0.0001). At microdose level, the best stand-alone sensitivity (97.6%) was comparable with CAD1 sensitivity (96.0%; p = 0.36; both with i30 reconstruction kernel). Pooled sensitivities for all nodules, doses, and reconstruction kernels on CAD1 ranged from 88.9% to 97.3% versus 49.6% to 73.9% for CAD2. The best sensitivity was achieved with standard-dose CT, i50 kernel, and CAD1 (97.3%) versus 96% with microdose CT, i30 or i50 kernel, and CAD1. MIP images and CAD1 had similar performance at both dose levels (p = 0.1313 and p = 0.48). CONCLUSION Submillisievert CT is feasible for detecting solid and ground-glass nodules that require soft-tissue kernels for MIP and CAD systems to achieve acceptable sensitivities. MIP reconstructions remain a valuable adjunct to the interpretation of chest CT for increasing sensitivity and have the advantage of significantly lower false-positive rates.


Pediatric Radiology | 2015

Pre- and postnatal imaging of Pai syndrome with spontaneous intrauterine closure of a frontal cephalocele

Tomas Dobrocky; Lukas Ebner; Benjamin Liniger; Christian Weisstanner; Enno Stranzinger

Pai syndrome is a rare congenital disorder characterized by cutaneous polyps of the face, pericallosal lipoma and median cleft lip. We report on a newborn girl with a variant of Pai syndrome presenting with all typical findings except a median cleft. In addition, fetal sonography and MRI showed the unique intrauterine evolution of a cephalocele into an atretic cephalocele.


Journal of Neurology, Neurosurgery, and Psychiatry | 2018

Systematic review and meta-analysis on outcome differences among patients with TICI2b versus TICI3 reperfusions: success revisited

Johannes Kaesmacher; Tomas Dobrocky; Mirjam Rachel Heldner; Sebastian Bellwald; Pascal J. Mosimann; Pasquale Mordasini; Sandra Bigi; Marcel Arnold; Jan Gralla; Urs Fischer

Objective A reperfusion quality of thrombolysis in cerebral infarction (TICI)≥2b has been set as the therapeutic angiography target for interventions in patients with acute ischaemic stroke. This study addresses whether the distinction between TICI2b and TICI3 reperfusions shows a clinically relevant difference on functional outcome. Methods A systematic literature review and meta-analysis was carried out and presented in conformity with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria to test the primary hypothesis that TICI2b and TICI3 reperfusions are associated with different rates of modified Rankin Scale (mRS) ≤2 at day 90. Secondary endpoints included rates of haemorrhagic transformations, mortality and excellent functional outcome (mRS ≤1). Summary estimates of ORs (sOR) with 95% CI were calculated using the inverse variance heterogeneity model accounting for multiple true effect sizes. Results Fourteen studies on 2379 successfully reperfused patients were included (1131 TICI3, 1248 TICI2b). TICI3 reperfusions were associated with higher rates of functional independence (1.74, 95% CI 1.44 to 2.10) and excellent functional outcomes (2.01, 95% CI 1.60 to 2.53), also after including adjusted estimates. The safety profile of patients with TICI3 was superior, as demonstrated by lower rates of mortality (sOR 0.59, 95% CI 0.37 to 0.92) and symptomatic intracranial haemorrhages (sOR 0.42, 95% CI 0.25 to 0.71). Conclusion TICI3 reperfusions are associated with superior outcome and better safety profiles than TICI2b reperfusions. This effect seems to be independent of time and collaterals. As reperfusion quality is the most important modifiable predictor of patients’ outcome, a more conservative definition of successful therapy and further evaluation of treatment approaches geared towards achieving TICI3 reperfusions are desirable.


American Journal of Neuroradiology | 2017

Endovascular Treatment of Dural Arteriovenous Fistulas of the Transverse and Sigmoid Sinuses Using Transarterial Balloon-Assisted Embolization Combined with Transvenous Balloon Protection of the Venous Sinus

Eike Immo Piechowiak; Felix Zibold; Tomas Dobrocky; Pascal J. Mosimann; David Bervini; Andreas Raabe; Jan Gralla; Pasquale Mordasini

BACKGROUND AND PURPOSE: Combined transarterial balloon-assisted endovascular embolization with double-lumen balloon microcatheters and concomitant transvenous balloon protection was described as a promising treatment technique for dural arteriovenous fistulae of the transverse and sigmoid sinus. The purpose of this study was to evaluate the technical efficacy and safety of this combined treatment technique. MATERIALS AND METHODS: Nine consecutive patients presenting with dural arteriovenous fistulas of the transverse and sigmoid sinuses underwent combined transarterial and transvenous balloon-assisted endovascular embolization. Prospectively collected data were reviewed to assess the technical success rate, complication rate, and clinical outcome. RESULTS: Six patients presented with clinically symptomatic Borden type I, and 3 patients, with Borden type II dural arteriovenous fistulas of the transverse and sigmoid sinuses (3 men, 6 women; mean age, 50.4 years). Transarterial embolization was performed with a double-lumen balloon with Onyx and concomitant transvenous sinus protection with a dedicated venous remodeling balloon. Complete angiographic occlusion at the latest follow-up (mean, 4.8 months) was achieved in 6 patients, and near-complete occlusion, in 2 patients. Clinical cure or remission of symptoms was obtained in 6 and 2 patients, respectively. One patient with a residual fistula underwent further treatment in which the dural arteriovenous fistula was cured by sinus occlusion. Complete occlusion of the dural arteriovenous fistula was visible on the follow-up angiography after final treatment in 8 patients. One patient refused follow-up angiography but was free of symptoms. There were no immediate or delayed postinterventional complications. CONCLUSIONS: Transarterial balloon-assisted embolization of dural arteriovenous fistulas of the transverse and sigmoid sinuses with combined transvenous balloon protection is safe and offers a high rate of complete dural arteriovenous fistula occlusion and remission of clinical symptoms.


CardioVascular and Interventional Radiology | 2015

Disastrous Portal Vein Embolization Turned into a Successful Intervention

Tomas Dobrocky; Joachim Kettenbach; Ruben Lopez-Benitez; Levent Kara

Portal vein embolization (PVE) may be performed before hemihepatectomy to increase the volume of future liver remnant (FLR) and to reduce the risk of postoperative liver insufficiency. We report the case of a 71-year-old patient with hilar cholangiocarcinoma undergoing PVE with access from the right portal vein using a mixture of n-butyl-2-cyanoacrylate and ethiodized oil. During the procedure, nontarget embolization of the left portal vein occurred. An aspiration maneuver of the polymerized plug failed; however, the embolus obstructing portal venous flow in the FLR was successfully relocated into the right portal vein while carefully bypassing the plug with a balloon catheter, inflating the balloon, and pulling the plug into the main right portal vein.


Acta radiologica short reports | 2014

Imaging findings in uncorrected tetralogy of Fallot and pulmonary atresia with major aortopulmonary collateral arteries and septic embolism.

Tomas Dobrocky; Thorsten Klink; Christian Weisstanner; Johannes T. Heverhagen; Andreas Christe

Tetralogy of Fallot (TOF) is one of the most common congenital heart malformations comprising a ventricular septal defect, right ventricular outflow tract obstruction, right ventricular hypertrophy, and overriding aorta. A rare variant includes pulmonary atresia and major aortopulmonary collateral arteries. Altered hemodynamics within the functional single-ventricle results in turbulent flow and predisposes to endocardial vegetation formation which may consequently lead to thromboembolic events. We present a rare case of an adult survivor of uncorrected TOF with pulmonary atresia.


Stroke | 2018

Rates and Quality of Preinterventional Reperfusion in Patients With Direct Access to Endovascular Treatment.

Johannes Kaesmacher; Mattia Giarrusso; Felix Zibold; Pascal J. Mosimann; Tomas Dobrocky; Eike Immo Piechowiak; Sebastian Bellwald; Marcel Arnold; Simon Jung; Marwan El-Koussy; Pasquale Mordasini; Jan Gralla; Urs Fischer

Background and Purpose— Preinterventional reperfusion before endovascular treatment (ET) is a benefit of bridging with intravenous tPA (tissue-type plasminogen activator). However, detailed data on reperfusion quality and rates of obviating ET in a cohort of patients with immediate access to ET is lacking. Purpose of this analysis was to evaluate prevalence and quality of preinterventional reperfusion in mothership patients. Methods— All mothership patients (n=627) from a prospective registry subjected to angiography with an intention to perform ET were reviewed. Preinterventional change of occlusion site (COS) was categorized into COS with Thrombolysis in Cerebral Infarction (TICI) 0/1, COS with TICI ≥2a, COS with TICI ≥2b, and COS with perfusion worsening. Predictors and clinical relevance were evaluated using multivariable logistic regression and results are displayed as adjusted odds ratios (aOR) and corresponding 95% confidence intervals (95% CI). Results— Prevalence of COS in all patients was 10.7% (95% CI, 8.3%–13.1%), subdividing into 2.7% COS with TICI 0/1, 6.2% COS with ≥TICI 2a (including 2.9% with TICI ≥2b), and 1.8% COS with perfusion worsening. Factors related to COS with ≥TICI 2a were intravenous tPA (aOR, 11.98; 95% CI, 4.5–31.6), cardiogenic thrombus origin (aOR, 2.3; 95% CI, 1.1–4.6), and thrombus length (aOR per 1 mm increase 0.926; 95% CI, 0.87–0.99). Additional ET was performed despite COS with ≥TICI 2a in 51.3%. COS with ≥TICI 2a showed a tendency for favorable outcomes (modified Rankin Scale, ⩽2; aOR, 2.65; 95% CI, 0.98–7.17). Rates of COS with ≥TICI 2a were particularly low in internal carotid artery and proximal M1 occlusions (2.2%; 95% CI, 0.9%–5%), where intravenous tPA was associated with perfusion worsening (aOR, 4.33; 95% CI, 1.12–16.80). Conclusions— Prevalence of preinterventional reperfusion is non-negligible in patients with direct access to ET and is clearly favored by intravenous tPA treatment. However, it is often incomplete and often requires additional ET. Preinterventional reperfusion of internal carotid artery and proximal M1 occlusions is rare and usually of low quality, where intravenous tPA may also promote perfusion worsening.


Stroke | 2018

Multivessel Occlusion in Patients Subjected to Thrombectomy: Prevalence, Associated Factors, and Clinical Implications

Johannes Kaesmacher; Pascal J. Mosimann; Mattia Giarrusso; Marwan El-Koussy; Felix Zibold; Eike Immo Piechowiak; Tomas Dobrocky; Raphael Meier; Simon Jung; Sebastian Bellwald; Marcel Arnold; Pasquale Mordasini; Urs Fischer; Jan Gralla

Background and Purpose— Patients with embolic large-vessel occlusion may present with additional coincidental acute occlusions within or distant from the involved territory, referred to as multivessel occlusion (MVO). Purpose of this study was to assess prevalence of MVO, associated factors, and clinical relevance in patients undergoing endovascular stroke treatment. Methods— Image data of consecutive endovascular candidates (n=720) with direct access to angiography were extracted from a prospective registry. Prevalence of MVO was assessed with multimodal magnetic resonance imaging/computed tomography and confirmed by intra-arterial angiography. Explorative analysis of associated factors and clinical relevance was evaluated using multivariable logistic regression including variables with P<0.15 in univariate comparison. Good functional outcome was defined as modified Rankin Scale score ⩽2 at day 90. Results— MVO was present in 10.7% of patients (95% confidence interval [CI], 6.4%–13.0%). Two, 3, and 4 concomitant occlusions were found in 80.5%, 16.9%, and 2.6% of MVO cases, respectively. Detection rate on initial radiological report was 54.5%. Downstream MVO was present in around one third of MVO (n=27/77, 35.1%), whereas all other MVO (n=50/77, 64.9%) occurred in different territories. Independent factors related to MVO were statin treatment (adjusted odds ratio [aOR], 0.477; 95% CI, 0.276–0.827), higher systolic blood pressure (aOR per mm Hg increase, 1.014; 95% CI, 1.005–1.023), and primary occlusion site M2 (aOR, 1.870; 95% CI, 1.103–3.170). MVO was related to lower rates of successful reperfusion (aOR, 0.549; 95% CI, 0.316–0.953) and lower rates of good functional outcome (aOR, 0.437; 95% CI, 0.207–0.923). Conclusions— Every tenth patient subjected to angiography for endovascular stroke treatment experienced MVO in our series, and only half were prospectively identified on preinterventional diagnostic imaging. Patients with MVO had higher baseline systolic blood pressure and were less often medicated with statins, an observation that warrants external validation and evaluation regarding causality. Occurrence of MVO has implication for treatment decisions, negatively affects endovascular treatment success, and is predictive of worse clinical outcome.

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