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Cardiac Perfusion MR
Perfusion assessment by cardiac magnetic resonance (CMR) is clinically applied for the detection of coronary artery disease. The standard method uses the injection of a contrast agent bolus and dynamic imaging while the bolus passes the myocardium. The contrast agent enhances the MR signal of blood so that tissue with reduced perfusion appears darker than well-perfused tissue. Today’s analysis of first-pass CMR images is a manual, interactive process resulting in relative scores such as "normal", "probably normal", "probably abnormal" or "abnormal". An overall perfusion score and scores related to the vascular territories are derived from the scores assigned to 16 standard segments. Although the use of such scores is a proven clinical method, CMR image analysis is time-consuming, not fully objective, and definitely requires expert readers.
Quantification of Cardiac Perfusion MR
The principle of CMR is similar to the use of tracers in PET, but involves complications due to the facts that the MRI signal is not always proportional to the contrast agent concentration, and that the MR acquisition is not volumetric. For more than a decade, researchers have worked on solving these problems and have recently approached truly quantitative, high-resolution perfusion CMR. These new solutions will broaden the applicability of CMR and bring added value to patients with globally reduced perfusion by multi-vessel obstruction or micro-vascular disease, which cannot be detected by a qualitative evaluation.
Cardiac MR Modeling with PCARDM
PMOD’s PCARDM tool is a joint development by PMOD Technologies and the CMR research group of ETH Zurich, Switzerland. It combines PMOD’s long-standing modeling expertise with ETH’s leading-edge MR methodology in a comprehensive package for qualitative and quantitative CMR image analysis. Using PCARDM, researchers in the field of CMR may apply the state-of-the art perfusion quantification approaches to their data and compare them with the standard qualitative outcome or an external gold standard. The PCARDM tool is most useful when bundled with accelerated MR acquisition sequences, whereby the full extent of the heart can be imaged in a single breath hold [1]. Currently, such a unique bundle is offered by GyroTools LLC for Philips MR research sites.