Quantitative multi-slice imaging of perfusion of the brain.

Aim: To develop an MR pulse sequence that allows the determination of the q uantitative perfusion of the brain by imaging the passage of a contrast age nt bolus with high temporal and spatial resolution. Methods: An EPI sequenc e, EPIDET (Echo Planar Imaging using Different Echo Times), was developed t hat allows the acquisition of different slices at different echo times. The passage of a contrast agent bolus was recorded in a slice through the larg e brain feeding arteries at a short echo time (TE1 = 17 ms), while brain pa renchyma was imaged in up to nine additional slices at a long echo time (TE 2 = 34 ms). Results: The different echo times allowed the determination of the arterial input function (signal decrease to 32%-59% of baseline intensi ty) and gave a sufficient signal reduction (14-22%) for reliable quantifica tion of perfusion in brain parenchyma. Conclusions: The combination of diff erent echo times of the DUAL-FLASH sequence and the multislice capability o f EPI sequences in the EPIDET sequence enables the quantification of multi- slice perfusion examinations. Compared to the DUAL-FLASH sequence EPIDET im proves spatial and temporal resolution.