7 Tesla MRI - Novel Imaging Biomarkers

Research Focus

The 7 Tesla (7T) oncologic imaging group at the German Cancer Research Center (DKFZ) focusses on the investigation and clinical translation of molecular MRI contrasts at ultra-high field strength. The goal is to further characterize tumor biology and to assess tumor response in clinical trials employing novel imaging biomarkers sensitive to cellular and microenvironmental information. The research group consists of an interdisciplinary team of scientists from the department of Radiology (E010) and the department of Medical Physics in Radiology (E020). Several projects are ongoing.

Dynamic Glucose-Enhanced (DGE) MRI: Prospective Investigation in Glioblastoma Patients

Fusion image of a T1-rho-weighted Dynamic Glucose-Enhanced MR and T2-w image, both acquired at 7.0 Tesla. The MR image shows a newly diagnosed patient with glioblastoma revealing increased glucose uptake, particularly in the tumor region. DGE MRI may help to identify highly proliferative tumor areas by visualizing increased glucose uptake due to high energy demand.
© dkfz.de

Contact: Paech/ Schünke

DGE MRI uses natural unlabeled glucose as biodegradable MR contrast agent. The aim of this work is to evaluate the contrast's potential to detect intracerebral regions of increased glucose uptake and potentially tumor metabolism following intravenous glucose administration. We could show that a dynamic glucose-enhanced contrast can be obtained that enables the identification of increased glucose uptake in gray matter structures of the brain and the delineation of pathophysiologically altered glucose uptake in glioblastoma, both with high temporal resolution. DGE MRI may allow glucose-enhanced imaging without the limitations of ionizing radiation and the expenses of radioisotopes.

Chemical Exchange Saturation Transfer (CEST) Imaging at 7 Tesla (7T) in Glioma Patients

Contact: Paech/ Schlemmer

CEST imaging is a non-invasive novel molecular MRI technique sensitive to endogenous proteins and their tissue specific concentration. Amide Proton Transfer (APT) and Nuclear Overhauser Enhancement (NOE) mediated CEST imaging are the most commonly used CEST-contrast. We could show that CEST MRI at 7T provides additional information on tumor heterogeneity and displays increased signal intensities beyond the borders of blood brain barrier disruption that may be linked to tumor infiltration. In ongoing research studies possible clinical applications such as therapy assessment or biopsy planning are investigated. Particularly, the response of brain tumors to radiation therapy is assessed in prospective clinical trials employing CEST MRI.

Mapping Brain Metabolism Using Dynamic O17 MRI at 7 Tesla in Healthy Volunteers and Glioblastoma Patients

Contact: Paech/ Niesporek

Dynamic 17O MRI utilizes the MR detectable oxygen isotope (17O) to determine functional dynamics in the human brain. The energy metabolism of the human brain (cerebral metabolic rate of oxygen consumption (CMRO2)) is an indicator of cell viability. In many diseases such as cancer (‘Warburg effect’), Parkinson’s or in Alzheimer’s disease CMRO2 is reduced and might therefore be an important diagnostic parameter. In 2012, the world wide first glioblastoma patient successfully underwent 17O MRI at 7 Tesla at the German Cancer Research Center. The method, which includes inhalation of 17O2 gas, was subsequently validated in a volunteer cohort study. In ongoing studies, we investigate the 17O contrast in brain tumor patients, in order to evaluate the method's potential as metabolic imaging technique in clinical cohorts.  

Monitoring Early Treatment Response Effects of Brain Cancer Patients in the Course of Radiotherapy Employing Longitudinal CEST and Sodium MR Imaging at 7T

Contact: Paech/ Meissner/ Behl/ Adeberg

Sodium (­­23Na) MR imaging can be used to assess the tissue sodium concentration (TSC) in human brain parenchyma and tumors. The aim of this work is the evaluation of variations in the TSC for brain tumor patients in the course of radiation therapy, both in the tumor region and surrounded tissue to monitor treatment effects. TSC is linked to the viability of cells in the observed tissue and could therefore give insights into early treatment response effects.

Furthermore, novel imaging biomarkers such as CEST MRI are investigated in radiotherapy patients in order to evaluate how these advanced imaging methods could contribute to clinical decision making.

CEST Imaging in Breast and Prostate Cancer at 7 Tesla and Clinical Field Strength (3T)

Contact: Paech/ Bickelhaupt/ Bonekamp

CEST MRI yields physiological information about protein concentration and pH of living tissue and therefore provides a new MR imaging (MRI) contrast which may highlight active tumor regions. Moreover, it may help to monitor tumor progression and guide treatment of cancer patients. Since CEST uses endogenous metabolite protons, this information is obtained without the need of contrast agents.

In our work, we evaluate the potential of CEST imaging at 7T for breast and prostate lesion detection and characterization. Ultimately, the research group is working on the translation of these novel MRI contrasts to clinical scanners (at 3T field strength) into benefit for patients in daily clinical practice.  

Selected Publications

1    Paech, D., Schuenke, P., Koehler, C., et al. (2017) T1ρ -weighted dynamic glucose enhanced MRI in the human brain. Radiology (in press)
 
2.    Schuenke, P., Paech, D., Koehler, C., et al. (2017) Fast and quantitative T1ρ-weighted Dynamic Glucose Enhanced MRI. Nature Scientific Reports 7, 42093 (2017); DOI: 10.1038/srep42093
 
3.    Paech, D., Burth, S., Windschuh, J., et al. (2015) Nuclear Overhauser Enhancement imaging of Glioblastoma at 7 Tesla: Region Specific Correlation with Apparent Diffusion Coefficient and Histology. PLoS ONE; 10(3):e0121220. DOI: 10.1371/journal.pone.0121220
 
4.    Zaiss, M., Windschuh, J., Paech, D., et al.  (2015) Relaxation-compensated CEST-MRI of the human brain at 7 T: Unbiased insight into NOE and amide signal changes in human glioblastoma. NeuroImage; 112. DOI: 10.1016/ j.neuroimage.2015.02.040
 
5.    Paech, D., Zaiss, M., Meissner, J-E., et al. (2014) Nuclear Overhauser Enhancement Mediated Chemical Exchange Saturation Transfer Imaging at 7 Tesla in Glioblastoma Patients. PLoS ONE; 9(8):e104181.

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