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.