Objectives: Magnetic resonance imaging in pulmonary oncology is limited because of unfavourable physical and physiological conditions in ventilated lung. Previous work showed operability of One Lung Flooding using saline in vivo in MR units, and that valuable conditions for ultrasound and thermal-based interventions exist. Therefore, this study investigates the morphological details of human lung during Lung Flooding to evaluate its further value focusing on MR-guided interventions.
Materials and methods: MR imaging was performed on 20 human lung lobes containing lung cancer and metastases. Lobes were intraoperatively flooded with saline and imaged using T1w Gradient Echo and T2 Spin Echo sequences at 1.5 T. Additionally, six patients received pre-operative MRI.
Results: During lung flooding, all lung tumours and metastases were visualized and clearly demarked from the surrounding lung parenchyma. The tumour mass appeared hyperintense in T1w and hypointense in T2w MR imaging. Intra-pulmonary bronchial structures were well differentiated in T2w and calcification in T1w MR sequences.
Conclusion: Superior conditions with new features of lung MRI were found during lung flooding with an unrestricted visualization of malignant nodules and clear demarcation of intra-pulmonary structures. This could lead to new applications of MR-based pulmonary interventions such as laser or focused ultrasound-based thermal ablations.
Keywords: HIFU; Lung cancer; Lung imaging; MR intervention; MRI; One lung flooding.