913Dual Bolus Dynamic Contrast Enhanced Cardiac Perfusion Imaging: Comparison of Turbo FLASH and True FISP

Abstract

Objective: To compare Turbo FLASH and True FISP data from 3 Tesla MRI for the analysis of cardiac perfusion flow. Methods: An anaesthetized healthy minipig was repeatedly (x 10) scanned with a 14 day interval with Turbo FLASH (x 5) and True FISP (x 5). Voxel size was 2.00 x 2.47 x 8 mm3 and prepulse delay time was TI=110 ms. Total scan time for 120 scans was 2:00 min. Prebolus and bolus CA were 1.2 ml and 6 ml 0.5 mmol/ml GdDTPA (Magnevist) with an injection speed of 4 ml/sec. Perfusion was assessed in 6 segments of the mid ventricle short axis view from the heart with eight reported methods: (1) Fermi, (2) Model-free Deconvolution, (3) modified Tofts, (4) Exchange, (5) Uptake, (6) Tofts, (7) Patlak, and (8) Upslope. We compared the outcome of the methods by regression analysis and by comparing medians and distribution of the data. Data yielding perfusion flow values of more than 200 ml/ 100 ml/ min that resulted for one of the 8 methods was completely discarded for all methods. Results: In Turbo FLASH imaging, 5 out of 30 measurements had to be discarded, whereas in True FISP imaging, only 1 out of 30 measurements had to be discarded. The highest correlations (R2>0.9) were observed for methods 1-3, 5, 6 (Turbo FLASH), and for 1, 3, 5, 6 (True FISP). From the Turbo FLASH data, the 5 methods 1-3, 5, 6 were considered as a reference. The Figure shows the box-plots of perfusion flow from the Turbo FLASH and True FISP data. Method 7 underestimates the flow in both cases. The median values of the methods 1-3, 5, (Turbo FLASH), and for all methods (True FISP) match within an interval of ±2 SD (computed from the 5 methods) around the median of the reference (which came out to be 56.0 ml/100 ml/ min for Turbo FLASH, respectively 50.0 ml/100ml/min for True FISP). Perfusion flow assessed by the methods 1-3, 8, (Turbo FLASH), and by the methods 2-4, 6, 8, (True FISP), was observed not to be significantly different from the chosen reference (p<0.01, related samples Wilcoxon rank test). Box plots for Turbo FLASH and True FISP Box plots for Turbo FLASH and True FISP