Statistical assessment of regional time-density measurement of myocardial perfusion

The measurement of time-density relationships of the myocardium in studies of magnetic resonance perfusion images is a clinical technique used in assessing myocardial perfusion. This article presents a new technique, allowing regional time-density measurement and display of myocardial perfusion with improved accuracy compared with traditional manual trace techniques. Moreover, a method using statistical methods to discriminate relative decreased perfusion regions that differ significantly from the normally perfused myocardial tissue is introduced.

Human datasets were obtained using a 1.5 T Signa Echospeed system (GE Medical Systems, Milwaukee, WI). The perfusion sequence was a 2D cardiac-gated fast gradient echo sequence with echo train readout, generating an in-plane pixel size of 1.46 mm2. Seven 10-mm-thick contiguous short axis tomographic slice images were obtained during a prolonged single breathhold. Data was collected at 30 time phases per slice image level during passage of 20 cc gadolinium contrast injected at a rate of 4-5 cc/sec into an antecubital vein.

Dilution properties can be determined and displayed as color-encoded regions superimposed on the myocardial slice according to the area of interest. Time-density curves throughout the perfusion study can be generated. Moreover, displays of normal and decreased perfusion areas can be used as statistically enhanced diagnosis guides.

This measurement, display, and diagnosis technique adds diagnostically important information to previous measurement and visualization techniques, providing enhanced detection and quantitative evaluation of regional deficits in myocardial contractility and perfusion, providing improved reliability and reproducibility of clinical diagnoses from MR-perfusion data.