Pulmonary perfusion imaging: Qualitative comparison of TCIR MRI and SPECT/CT in porcine lung

•Evaluation of two-compartment inversion recovery in a multimodal animal MRI-study.•Qualitative comparison of TCIR shows similar blood distribution as gold standard.•Delineation and homogeneity of TCIR comparable or superior to standard methods.

ObjectivesTo validate the anatomical accuracy, homogeneity and sensitivity of two-compartment modeled inversion recovery (TCIR) magnetic resonance imaging (MRI) in a multimodal animal experiment as a non-invasive alternative to standard functional imaging techniques.MethodsSeven pigs were studied on a 1.5 T whole-body MR scanner and SPECT/CT. The specimens were intubated and maintained in general anesthesia throughout the experiment. TCIR maps of the fractional pulmonary blood volume were compared to dynamic contrast enhanced MRI and SPECT/CT via a region of interest (ROI) based reader study. A comprehensive statistical analysis was performed on the coefficient of variation to evaluate homogeneity properties. Sensitivity was assessed by detecting gravitation dependent perfusion variation and delineation of pathological areas.ResultsThe fPBV-maps of all examined specimens indicate a superior homogeneity in the computed values (p < 1.3 × 10−4). The sensitivity of the TCIR maps to a gravitation effect on the blood distribution was verified and a similar anteroposterior signal and count dependency was observed in DCE MRI and SPECT. Bland–Altman analysis showed no significant intra- or inter-observer difference within the ROI reader study (p > 0.06).ConclusionSuperior information content, significantly higher homogeneity and similar sensitivity of TCIR when compared to DCE and SPECT/CT demonstrated the feasibility of TCIR MRI as an alternative contrast agent-free, non-invasive functional lung imaging approach.