The assessment of functional liver tissue is of growing clinical importance in predicting post-operative outcomes and optimizing liver-directed therapies. Quantitative Blood Oxygen Level Dependent (qBOLD) imaging offers a non-invasive MRI-based method to measure tissue oxygenation via the R2′ relaxation parameter. R2′ is defined as the difference between R2* and R2, and reflects magnetic field inhomogeneities caused by deoxyhemoglobin, among other factors.

This research explores the feasibility of estimating R2′ in the liver using a multiparametric qBOLD (MqBOLD) approach under free-breathing conditions. Two MRI sequences, one for R2 and one for R2* mapping, were optimized and applied at 1.5 T and 3 T. A cohort of five healthy volunteers was scanned to evaluate image quality and relaxation rates across field strengths and breathing techniques.

Results showed that R2′ mapping is feasible using an MqBOLD approach under predominantly free-breathing conditions, without apparent motion artifacts. The mean R2′ values in homogeneous liver parenchyma were 12.7 ± 2.8 s⁻¹ at 1.5 T and 24.6 ± 4.8 s⁻¹ at 3 T. Both 1.5 T and 3 T proved suitable for R2′ mapping. While 1.5 T offered better image quality, 3 T provided more reliable quantitative results and greater patient comfort.

As a proof of concept, the MqBOLD protocol was successfully integrated into a routine clinical liver MRI scan protocol for a patient with neuroendocrine liver metastasis. The additional scan time was under three minutes, and the resulting relaxation maps showed contrast between tumor and healthy liver tissue.

In conclusion, this research establishes the feasibility of R2′ mapping in the liver using a multiparametric MRI approach under mostly free-breathing conditions. It presents a foundation for non-invasive liver oxygenation imaging, with the potential to evolve into a clinically applicable tool for functional liver assessment.

Background: Oropharyngeal squamous cell carcinoma (OPSCC) not associated with the human papillomavirus (HPV) have a poor prognosis compared to their HPV-associated counterpart. In literature diffusion-weighted imaging (DWI) shows great potential as a biomarker for treatment response in HPV-associates OPSCC. For this study the possibility of using DWI parameters as biomarker for treatment response during treatment of HPV-negative OPSCC is investigated. Tumor size and shrinkage have also been investigated.
Methods: In this study sixteen patients with HPV-negative OPSCC who underwent (chemo-)radiotherapy have been included. All are current and/or former smokers. At two time point an DWI-MRI scan took place, before and 2 weeks into treatment. The mean apparent diffusion coefficient (ADC) and Non-Gaussian Intravoxel Incoherent Motion Imaging (NG-IVIM) parameters based on the gross tumor volume (GTV) have been calculated. The parameters and differences in parameters have been compared between patients that responded well to treatment and patients with progressive disease.
Results: At pre- and midtreatment no significant differences have been found between the Complete Response (CR) and Progressive Disease(PD) patient groups. Diffusion coefficient D showed a significant change between pre- and midtreatment, with an increase for PD and decrease for CR. When comparing the residual region to the region that had disappeared after two weeks based on pretreatment data significant differences have been found in ADC, D and f for CR, as well as f for PD.
Conclusion: Changes in D during treatment have shown to be a significant predictor for treatment response. However this study is limited by a small patient group and more research with larger cohorts and additional biomarkers is needed to develop reliable clinical decision-making tools.