WE-FG-206-07: Assessing the Lung Function of Patients with Non-Small Cell Lung Cancer Using Hyperpolarized Xenon-129 Dissolved-Phase MRI.

PURPOSE: Hyperpolarized xenon-129 dissolved-phase MRI is the first imaging technique that allows 3-dimensional regional mapping of ventilation and gas uptake by tissue and blood the in human lung. Multiple outcome measures can be produced from this method. Existing studies in subjects with major lung diseases compared to healthy controls demonstrated high sensitivities of this method to pulmonary physiological factors including ventilation, alveolar tissue density, surface-to-volume ratio, pulmonary perfusion and gas-blood barrier thickness. The purpose of this study is to evaluate the utility of this new imaging tool to assess the lung function in patients with non-small cell lung cancer (NSCLC).

METHODS: Ten healthy controls (age: 63±10) and five patients (age: 62±13) with NSCLC underwent the xenon-129 dissolved-phase MRI, pulmonary function test (PFT) and CT for clinical purpose. Three outcome measures were produced from xenon-129 dissolved-phase MRI, including ventilation defect fraction (Vdef%) reflecting the airflow obstruction, tissue-to-gas ratio reflecting lung tissue density, and RBC-to-tissue ratio reflecting pulmonary perfusion and gas exchange.

RESULTS: Compared to healthy controls, patients with NSCLC showed more ventilation defects (NSCLC: 22±6%; control: 40±18%; P=0.01), lower tissue-to-gas (NSCLC: 0.82±0.31%; control: 1.07±0.13%; P=0.05) and RBC-to-tissue ratios (NSCLC: 0.82±0.31%; control: 1.07±0.13%; P=0.01). Maps for ventilation and gas uptake by tissue and blood were highly heterogeneous in the lungs of patients. Vdef% and RBC-to-tissue ratios in all 15 subjects correlated with corresponding global lung functional measures from PFT: FEV1/FVC (R=-0.91, P<0.001) and DLCO % predicted (R=0.54, P=0.03), respectively. The tissue-to-gas ratios correlated with tissue density (HU) measured by CT (R=0.88, P<0.001).

CONCLUSION: With the unique ability to provide detailed information about lung function including ventilation, tissue density, perfusion and gas exchange with 3D resolution, hyperpolarized xenon-129 dissolved-phase MRI has high potential to be used as an important reference for radiotherapy treatment planning and for evaluating the side effects of the treatment. Receive research support and funding from Siemens.