Ramona Woitek

Dr. Ramona Woitek

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Research Focus & Metrics

Academic Career Length

19Years (2008-Present)

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

Representative Publications

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21 January 2020 in Proceedings of the National Academy of Sciences
Verified
Journal Article
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FGFerdia Gallagher
Ferdia Gallagher
Ramona WoitekRamona Woitek
Ramona Woitek
MMMary A. McLean
Mary A. McLean
AGAndrew B. Gill
Andrew B. Gill
RGRaquel Manzano Garcia
Raquel Manzano Garcia
KBKevin M. Brindle
Kevin M. Brindle
Our purpose is to investigate the feasibility of imaging tumor metabolism in breast cancer patients using 13 C magnetic resonance spectroscopic imaging (MRSI) of hyperpolarized 13 C label exchange between injected [1- 13 C]pyruvate and the endogenous tumor lactate pool. Treatment-naïve breast cancer patients were recruited: four triple-negative grade 3 cancers; two invasive ductal carcinomas that were estrogen and progesterone receptor-positive (ER/PR+) and HER2/neu-negative (HER2−), one grade 2 and one grade 3; and one grade 2 ER/PR+ HER2− invasive lobular carcinoma (ILC). Dynamic 13 C MRSI was performed following injection of hyperpolarized [1- 13 C]pyruvate. Expression of lactate dehydrogenase A (LDHA), which catalyzes 13 C label exchange between pyruvate and lactate, hypoxia-inducible factor-1 (HIF1α), and the monocarboxylate transporters MCT1 and MCT4 were quantified using immunohistochemistry and RNA sequencing. We have demonstrated the feasibility and safety of hyperpolarized 13 C MRI in early breast cancer. Both intertumoral and intratumoral heterogeneity of the hyperpolarized pyruvate and lactate signals were observed. The lactate-to-pyruvate signal ratio (LAC/PYR) ranged from 0.021 to 0.473 across the tumor subtypes (mean ± SD: 0.145 ± 0.164), and a lactate signal was observed in all of the grade 3 tumors. The LAC/PYR was significantly correlated with tumor volume ( R = 0.903, P = 0.005) and MCT 1 ( R = 0.85, P = 0.032) and HIF1α expression ( R = 0.83, P = 0.043). Imaging of hyperpolarized [1- 13 C]pyruvate metabolism in breast cancer is feasible and demonstrated significant intertumoral and intratumoral metabolic heterogeneity, where lactate labeling correlated with MCT1 expression and hypoxia.

28 April 2020 in Journal of Clinical Medicine
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ASAriane Steindl
Ariane Steindl
JLJohannes Leitner
Johannes Leitner
MSMatthias Schwarz
Matthias Schwarz
KNKarl-Heinz Nenning
Karl-Heinz Nenning
UAUlrika Asenbaum
Ulrika Asenbaum
Julia FurtnerJulia Furtner
Julia Furtner
Temporal muscle thickness (TMT) was investigated as a novel surrogate marker on MRI examinations of the brain, to detect patients who may be at risk for sarcopenia. TMT was analyzed in a retrospective, normal collective cohort (n = 624), to establish standard reference values. These reference values were correlated with grip strength measurements and body mass index (BMI) in 422 healthy volunteers and validated in a prospective cohort (n = 130) of patients with various neurological disorders. Pearson correlation revealed a strong association between TMT and grip strength (retrospective cohort, ρ = 0.746; p < 0.001; prospective cohort, ρ = 0.649; p < 0.001). A low or no association was found between TMT and age (retrospective cohort, R2 correlation coefficient 0.20; p < 0.001; prospective cohort, ρ = −0.199; p = 0.023), or BMI (retrospective cohort, ρ = 0.116; p = 0.042; prospective cohort, ρ = 0.227; p = 0.009), respectively. Male patients with temporal wasting and unintended weight loss, respectively, showed significantly lower TMT values (p = 0.04 and p = 0.015, unpaired t-test). TMT showed a high correlation with muscle strength in healthy individuals and in patients with various neurological disorders. Therefore, TMT should be integrated into the diagnostic workup of neurological patients, to prevent, delay, or treat sarcopenia.

19 October 2021 in Radiology
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Journal Article
Closed access
SHSarah E. Hickman
Sarah E. Hickman
Ramona WoitekRamona Woitek
Ramona Woitek
ELElizabeth Phuong Vi Le
Elizabeth Phuong Vi Le
YIYu Ri Im
Yu Ri Im
CLCarina Mouritsen Luxhøj
Carina Mouritsen Luxhøj
FGFiona J. Gilbert
Fiona J. Gilbert
Retrospective studies demonstrate the performance of stand-alone machine learning applications in screening mammography can reach reader performance and can provide a mechanism for case triage, whi... Background Advances in computer processing and improvements in data availability have led to the development of machine learning (ML) techniques for mammographic imaging. Purpose To evaluate the re...

3 January 2017 in European Radiology
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Journal Article
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Julia FurtnerJulia Furtner
Julia Furtner
ABAnna S. Berghoff
Anna S. Berghoff
OAOmar M. Albtoush
Omar M. Albtoush
Ramona WoitekRamona Woitek
Ramona Woitek
UAUlrika Asenbaum
Ulrika Asenbaum
MPMatthias Preusser
Matthias Preusser
Objectives To evaluate the prognostic relevance of temporal muscle thickness (TMT) in brain metastasis patients. Methods We retrospectively analysed TMT on magnetic resonance (MR) images at diagnosis of brain metastasis in two independent cohorts of 188 breast cancer (BC) and 247 non-small cell lung cancer (NSCLC) patients (overall: 435 patients). Results Survival analysis using a Cox regression model showed a reduced risk of death by 19% with every additional millimetre of baseline TMT in the BC cohort and by 24% in the NSCLC cohort. Multivariate analysis included TMT and diagnosis-specific graded prognostic assessment (DS-GPA) as covariates in the BC cohort (TMT: HR 0.791/CI [0.703–0.889]/p < 0.001; DS-GPA: HR 1.433/CI [1.160–1.771]/p = 0.001), and TMT, gender and DS-GPA in the NSCLC cohort (TMT: HR 0.710/CI [0.646–0.780]/p < 0.001; gender: HR 0.516/CI [0.387–0.687]/p < 0.001; DS-GPA: HR 1.205/CI [1.018–1.426]/p = 0.030). Conclusion TMT is easily and reproducibly assessable on routine MR images and is an independent predictor of survival in patients with newly diagnosed brain metastasis from BC and NSCLC. TMT may help to better define frail patient populations and thus facilitate patient selection for therapeutic measures or clinical trials. Further prospective studies are needed to correlate TMT with other clinical frailty parameters of patients. Key Points • TMT has an independent prognostic relevance in brain metastasis patients. • It is an easily and reproducibly parameter assessable on routine cranial MRI. • This parameter may aid in patient selection and stratification in clinical trials. • TMT may serve as surrogate marker for sarcopenia.

14 February 2015 in European Radiology
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HRHelmut Ringl
Helmut Ringl
MLMathias Lazar
Mathias Lazar
MTMichael Töpker
Michael Töpker
Ramona WoitekRamona Woitek
Ramona Woitek
HPHelmut Prosch
Helmut Prosch
TMThomas Mang
Thomas Mang

28 October 2008 in European Journal of Immunology
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JKJohanna Kober
Johanna Kober
JLJudith Leitner
Judith Leitner
CKChristoph Klauser
Christoph Klauser
Ramona WoitekRamona Woitek
Ramona Woitek
OMOtto Majdic
Otto Majdic
PSPeter Steinberger
Peter Steinberger
Activating signals generated by members of the tumour necrosis factor receptor superfamily upon interaction with their cognate ligands play important roles in T‐cell responses. Members of the tumour necrosis factor family namely 4‐1BBL, OX40L, CD70, GITRL, LIGHT and CD30L have been described to function as costimulatory molecules by binding such receptors on T cells. Using our recently described system of T‐cell stimulator cells we have performed the first study where all these molecules have been assessed and compared regarding their capacity to costimulate proliferation and cytokine production of human T cells. 4‐1BBL, which we found to be the most potent molecule in this group, was able to mediate sustained activation and proliferation of human T cells. OX40L and CD70 were also strong inducers of T‐cell proliferation, whereas the costimulatory capacity of human GITRL was significantly lower. Importantly CD30L and LIGHT consistently failed to act costimulatory on human T cells, and we therefore suggest that these molecules might be functionally distinct from the costimulatory members of this family.