Feasibility of combining MR perfusion, angiography, and ³He ventilation imaging for evaluation of lung function in a porcine model

Rationale and Objective. To assess the feasibility of combining magnetic resonance (MR) perfusion, angiography, and ³He ventilation imaging for the evaluation of lung function in a porcine model. Materials and Methods. Fourteen consecutive porcine models with externally delivered pulmonary emboli and/or airway occlusions were examined with MR perfusion, angiography, and ³He ventilation imaging. Ultrafast gradient-echo sequences were used for 3D perfusion and angiographic imaging, in conjunction with the use of contrast-agent injections. 2D multiple-section ³He imaging was performed subsequently via the inhalation of hyperpolarized ³He gas. The diagnostic accuracy of MR angiography for detecting pulmonary emboli was determined by two reviewers. The diagnostic confidence for different combinations of MR techniques was rated on the basis of a 5-point grading scale (5 = definite). Results. The sensitivity, specificity, and accuracy of MR angiography for detecting pulmonary emboli were approximately 85.7%, 90.5%, and 88.1%, respectively. The interobserver agreement was very strong (k = 0.82). There was a clear tendency for confidence to increase when first perfusion and then ventilation imaging were added to the angiographic image (Wilcoxon signed ranks test, P = 0.03). Conclusion. The combination of the three methods of MR perfusion, angiography, and ³H ventilation imaging may provide complementary information on abnormal lung anatomy and function.