Detecting small pulmonary emboli with dual energy

The following question has been sent by  Minh Truong:

Please, give me a advise, How to compare between CT perfusion and MR perfusion, which one is better than? thank you and best regards

Thorsten R.C. Johnson, M.D., University Hospitals Grosshadern, Munich:

Both MR and CT pulmonary perfusion imaging are currently still being evaluated scientifically and so far not integrated into routine clinical protocols. The effort for MR perfusion imaging is much greater, scan time longer, and it is more expensive, but it provides a dynamic ‘4D’ dataset. It is partially used to evaluate clots in patients with pulmonary hypertension due to chronic recurrent pulmonary embolism for surgical planning, i.e. ebolectomy. CT on the other hand is routinely performed for the evaluation of pulmonary embolism anyway, and the perfusion information is available without additional effort, contrast material, radiation dose or cost, without additional scan time or breath holding. The ‘perfusion’ information is acutally an interpretation of a static arterial phase, and agreement with actual perfusion imaging is still being evaluated in clinical studies; there will be a paper on the agreement with scintigraphy in an upcoming special issue of European Journal of Radiology. This technique can enhance the detection of subsegmental pulmonary embolism and support the estimation of the relevance of embolism for perfusion, which should be more relevant for the clinical outcome.