Dynamic contrast-enhanced MRI Perfusion of the Lung – Feasibility and Accuracy in Patients with COPD, lung cancer and pulmonary embolism

Abstract

Introduction: Dynamic contrast enhanced MRI (DCE-MRI) of the lung used to have its limits concerning spatial and temporal resolution and required breath-hold during the examination. However, new techniques allow for an acquisition of 4D datasets of the lung with higher temporal resolution during free breathing. Purpose of this study is the evaluation of accuracy and feasibility of MRI for the robust assessment of lung perfusion in daily routine in comparison with perfusion scintigraphy serving as standard of reference. Methods: This is a retrospective study including all patients who underwent scintigraphy and DCE-MRI at our institute between 06/2012 and 06/2014 for different clinical indications. A T1-weighted gradient echo sequence with echo sharing (TWIST) on a 1.5 T Magnetom Area scanner (Siemens Healthcare, Erlangen, Germany) was used to acquire 4D datasets of the whole lung with temporal resolution of 1.5 seconds and 20 series in total, during free breathing. This data was evaluated using the dedicated “Pulmo MR” software (Fraunhofer-MEVIS, Bremen, Germany) which included particular algorithms for motion correction and to suppress larger vessels (VS) within the lung to obtain several quantitative perfusion read-outs such as blood flow (PBF) and blood volume (PBV) for the pulmonary parenchyma. These datasets were compared with corresponding regions on scintgraphic results using scatter plots, Blant-Altman-plots and Spearman's rank correlation. Results: Currently we have evaluated datasets of 20 patients. The findings demonstrate a high agreement of perfusion parameters found at MRI using VS in comparison to scintigraphy especially in the basal parts of the lungs. In the apical parts MRI perfusion seems to constantly reveal lower perfusion ratios than scintigraphy. Discussion: MR-based 4D lung perfusion is robustly feasible and provides quantitative functional parameters allowing for a substantiated advanced assessment of pulmonary perfusion in comparison with scintigraphy in the major clinical settings COPD, lung cancer and pulmonary embolism.