Inflow-weighted pulmonary perfusion: comparison between dynamic contrast-enhanced MRI versus perfusion scintigraphy in complex pulmonary circulation
1 Department of Electronic and Computer Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan
2 Section of Thoracic and Circulation Imaging Department of Radiology, Kaohsiung Veterans General Hospital, No.386, Ta-Chung 1st Road, 813, Kaohsiung, Taiwan, People’s Republic of China
3 Graduate Institute of Applied Physics, National Chengchi University, Taipei, Taiwan
4 Department of Electrical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan
5 Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan
6 Faculty of Medicine, School of Medicine, National Yang Ming University, Taipei, Taiwan
7 Department of Pediatrics, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
8 Department of Nuclear Medicine, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
9 Institute of Clinical Medicine, School of Medicine, National Yang Ming University, Taipei, Taiwan
Journal of Cardiovascular Magnetic Resonance 2013, 15:21 doi:10.1186/1532-429X-15-21Published: 28 February 2013
Due to the different properties of the contrast agents, the lung perfusion maps as measured by 99mTc-labeled macroaggregated albumin perfusion scintigraphy (PS) are not uncommonly discrepant from those measured by dynamic contrast-enhanced MRI (DCE-MRI) using indicator-dilution analysis in complex pulmonary circulation. Since PS offers the pre-capillary perfusion of the first-pass transit, we hypothesized that an inflow-weighted perfusion model of DCE-MRI could simulate the result by PS.
22 patients underwent DCE-MRI at 1.5T and also PS. Relative perfusion contributed by the left lung was calculated by PS (PSL%), by DCE-MRI using conventional indicator dilution theory for pulmonary blood volume (PBVL%) and pulmonary blood flow (PBFL%) and using our proposed inflow-weighted pulmonary blood volume (PBViwL%). For PBViwL%, the optimal upper bound of the inflow-weighted integration range was determined by correlation coefficient analysis.
The time-to-peak of the normal lung parenchyma was the optimal upper bound in the inflow-weighted perfusion model. Using PSL% as a reference, PBVL% showed error of 49.24% to −40.37% (intraclass correlation coefficient RI = 0.55) and PBFL% had error of 34.87% to −27.76% (RI = 0.80). With the inflow-weighted model, PBViwL% had much less error of 12.28% to −11.20% (RI = 0.98) from PSL%.
The inflow-weighted DCE-MRI provides relative perfusion maps similar to that by PS. The discrepancy between conventional indicator-dilution and inflow-weighted analysis represents a mixed-flow component in which pathological flow such as shunting or collaterals might have participated.