Michael Sonnberger

Dr. Michael Sonnberger


Research Focus & Metrics

Academic Career Length

6Years (2021-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
31 October 2025 in Brain Sciences
Verified
Journal Article
Open access
PDF file
MGMaria Gollwitzer
Maria Gollwitzer
VMVanessa Mazanec
Vanessa Mazanec
MSMarkus Steindl
Markus Steindl
BABaran Atli
Baran Atli
NSNico Stroh-Holly
Nico Stroh-Holly
MGMatthias Gmeiner
Matthias Gmeiner
Background: Cerebral vasospasm is a frequent and severe complication after aneurysmal subarachnoid hemorrhage (aSAH), often causing delayed cerebral ischemia (DCI) and poor outcomes. Despite progress in neurocritical care, early vasospasm prediction after aSAH remains challenging due to its multifactorial nature but is essential for timely intervention. Methods: We retrospectively analyzed 503 consecutive patients with spontaneous subarachnoid hemorrhage (SAH) treated between 2013 and 2018. Of these, 345 with angiographically confirmed aSAH were included in the primary analysis, and 158 SAH cases in a sensitivity analysis. We extracted demographic, clinical, and imaging parameters including age, sex, Hunt and Hess grade, Fisher scale, aneurysm and treatment features, external ventricular drainage (EVD), and central nervous system (CNS) infection. Seven supervised machine learning (ML) models, including logistic regression and gradient-boosted trees, were trained using nested cross-validation and evaluated by AUC-ROC, AUC-PR, accuracy, precision, sensitivity, specificity, and F1 score. Results: Over half of aSAH patients developed moderate to severe vasospasm. Independent predictors included younger age, higher Hunt and Hess and Fisher grades, and EVD placement (all p < 0.001). Logistic regression achieved the best discrimination (AUC-ROC 0.723), while tree-based models reached higher sensitivity (0.867) at the expense of specificity. Aneurysmal etiology further increased vasospasm risk (OR 4.72). Conclusions: Routinely available clinical and imaging parameters enable reliable ML-based vasospasm prediction after aSAH. Logistic regression provided the best balance between accuracy and interpretability, while tree-based models optimized sensitivity. This web-based, interpretable ML tool—one of the first using routine clinical data—may support the bedside prediction of vasospasm and requires prospective validation.

7 June 2021 in Diagnostics
Verified
Journal Article
Open access
PDF file
RPRobert Pichler
Robert Pichler
OKOgnian Kalev
Ognian Kalev
BTBerndt Tomancok
Berndt Tomancok
MSMichael Sonnberger
Michael Sonnberger
DEDaniela Ehrlich
Daniela Ehrlich
MHMarina Hodolic
Marina Hodolic
Somatostatin analogues are considered to be the first line of treatment in acromegaly. Somatostatin analogues of the first generation mainly target the somatostatin receptor (SSTR) subtype 2 and have been proven efficient in the majority of patients with acromegaly. Pasireotide was the first somatostatin analogue also substantially targeting the SSTR subtype 5. An efficient drug for Cushing’s disease tailored to suboptimal-responding patients with acromegaly then became available. We immunohistochemically investigated SSTR subtypes expression in pituitary adenomas from operated acromegaly patients with clinical relapse and a complicated clinical course. Patients received pasireotide in the course of their disease. The predictive value of SSTR subtypes immunhistochemical analysis for the therapeutic response is discussed.

26 October 2024 in Brain Sciences
Verified
Journal Article
Open access
PDF file
NSNico Stroh-Holly
Nico Stroh-Holly
PRPhilip Rauch
Philip Rauch
HSHarald Stefanits
Harald Stefanits
PHPhilipp Hermann
Philipp Hermann
HWHelga Wagner
Helga Wagner
MGMatthias Gmeiner
Matthias Gmeiner
Background/Objectives: Microsurgical clipping has traditionally been considered a standard treatment for middle cerebral artery (MCA) aneurysms. Recently, a caseload reduction related to improved endovascular treatment options has occurred in cerebrovascular neurosurgery. Therefore, studies that report the clinical and radiological outcomes after clipping are highly warranted. Methods: Patients with an unruptured MCA bifurcation aneurysm, who were surgically treated at the Department of Neurosurgery in Linz between 2002 and 2019, were included in this study. Clinical and radiological outcome parameters were evaluated for each patient. Results: Overall, 272 patients were eligible for inclusion. Complete aneurysm occlusion was demonstrated in 266 (99.3%) of the 268 (98.5%) patients who underwent postoperative digital subtraction angiography. In six (2.2%) patients, a permanent new neurological deficit (pNND) persisted after treatment. Intraoperative aneurysm rupture was a significant factor (p = 0.0049) in the logistic regression. At the last follow-up, only two patients (0.7%) had an unfavorable outcome (mRS > 2). More recent surgeries were associated with fewer cases of pNND (p = 0.009). A transient new neurological deficit occurred in 13 patients (4.8%), with aneurysm size being a significant risk factor (p = 0.009). Surgical site infections were reported in four patients (1.5%), with patient age (p = 0.039) and time (p = 0.001) being significant factors. Two patients died (0.7%) perioperatively and two patients (0.7%) needed a retreatment in the long-term follow-up. Conclusions: The findings indicate that microsurgical clipping is a safe procedure with minimal need for retreatment. It achieves a high occlusion rate while maintaining a very low rate of adverse outcomes. Continuous intraoperative enhancements over time have contributed to a progressive improvement in clinical outcomes in recent years. This trend is exemplified by the absence of detectable pNND in the era of ICG angiography. Consequently, these data support the conclusion that microsurgical clipping should still be considered an appropriate treatment option for unruptured MCA bifurcation aneurysms.

27 November 2025 in Brain Sciences
Verified
Journal Article
Open access
PDF file
NSNico Stroh-Holly
Nico Stroh-Holly
SAStefan Aspalter
Stefan Aspalter
MVMilan S. Vosko
Milan S. Vosko
BLBenjamin Laudien
Benjamin Laudien
PHPhilipp Hermann
Philipp Hermann
MGMatthias Gmeiner
Matthias Gmeiner
Background/Objectives: Unruptured aneurysms of the anterior communicating artery (AComA) are associated with a higher risk of rupture and present unique anatomical challenges. Although endovascular techniques have advanced considerably, microsurgical clipping continues to represent an essential treatment option, particularly for complex cases. We conducted a retrospective analysis to evaluate outcomes of microsurgical clipping for unruptured AComA aneurysms over an 18-year period at a high-volume tertiary neurosurgical center. Methods: A retrospective analysis was conducted on 106 patients who underwent microsurgical clipping for unruptured AComA aneurysms between 2002 and 2020. Preoperative, intraoperative, and postoperative parameters were assessed. Excluded were previously ruptured or previously surgically treated aneurysms. Logistic regression models were used to identify predictors of postoperative complications with a focus on aneurysm projection. Results: Complete angiographic occlusion was achieved in 92.2% of cases, with a retreatment rate of 0.9%, which is comparable to the recent literature. Permanent neurological deficits occurred in 5.7% of patients. Posterior aneurysm projection was significantly associated with postoperative infarction and permanent neurological deficits. Intraoperative ICG angiography was associated with a reduced risk of ischemic complications. Conclusions: Microsurgical clipping remains a safe and effective treatment for unruptured AComA aneurysms in selected patients, offering durable occlusion and low complication rates. Aneurysm projection is a key predictor of outcome, and intraoperative ICG angiography significantly enhances surgical safety. These findings support the continued role of microsurgery in the interdisciplinary management of AComA aneurysms.

23 October 2025 in Life
Verified
Journal Article
Open access
PDF file
VBVincent Boehm
Vincent Boehm
BIBogdan-Andrei Ianosi
Bogdan-Andrei Ianosi
CKCaterina Kulyk
Caterina Kulyk
FGFranz Gruber
Franz Gruber
MLMaria Lorenz
Maria Lorenz
RHRaimund Helbok
Raimund Helbok
(1) Background: To report two cases of severe tick-borne encephalitis (TBE) in elderly patients presenting with a previously undescribed subarachnoid T2/FLAIR hyperintensity on repeated MRI examinations, which may serve as an early imaging biomarker of disease severity. (2) Methods: Two unvaccinated 82-year-old patients (one male and one female) presented with acute encephalitis and required intensive care. Serial brain MRI, EEG, CSF analysis, and neurophysiological assessments were performed. (3) Results: Both patients showed rapid progressive neurological deterioration in the context of TBE, confirmed by elevated serum and CSF IgM and IgG titers. Early follow-up MRI revealed striking sulcal hyperintensities on T2/FLAIR sequences, interpreted as protein-rich subarachnoid inflammatory changes. These changes paralleled clinical worsening and resolved on follow-up imaging. The male patient developed meningoencephalomyeloradiculitis, remained comatose, and died from respiratory failure (the brain and spinal cord were examined postmortem). The female patient had meningoencephaloradiculitis with severe dysphagia and was discharged with a modified Rankin Scale score of four. Both patients demonstrated epileptiform EEG activity. The CSF analysis revealed markedly elevated total protein, lactate, tau protein, and CXCL13, as evidence of blood–brain barrier disruption and inflammatory neurodegeneration. (4) Conclusions: We describe acute subarachnoid T2/FLAIR hyperintensity in TBE as an imaging feature that may correlate with severe systemic inflammation and a poor prognosis. This radiological finding could serve as a potential early prognostic marker in TBE.

2 April 2026
Verified
Book Chapter
Open access
PDF file
EGElke Ruth Gizewsk
Elke Ruth Gizewsk
HDHannes Deutschmann
Hannes Deutschmann
GKGregor Kasprian
Gregor Kasprian
JFJulia Furtner
Julia Furtner
MSMichael Sonnberger
Michael Sonnberger
JTJohannes Trenkler
Johannes Trenkler
The Austrian Society of Neuroradiology has, even though officially funded in 1990, a long tradition due to the work of pioneers since 1905. Today, diagnostic Neuroradiology and most neurointerventional procedures are provided by radiologists. Main activities of the society are the organization of annual meetings, support teaching and running a well-established research program for young radiologists but also supports science in Neuroradiology. Scientific publishing is encouraged by the scientific Arthur Schüller Award, provided and sponsored by the Austrian Society of Neuroradiology annually. Corresponding to the tremendous progress of clinical neuroscience in the last decades, neuroradiology also developed more and more to an independent subject. The Austrian Society of Neuroradiology aims to promote diagnostic and interventional neuroradiology in clinical practice, teaching and research and rises to the challenge to establish an independent subspecialty in Austria.