Quantitative multi-slice imaging of perfusion of the brain.

Aim: To develop an MR pulse sequence that allows the determination of the quantitative perfusion of the brain by imaging the passage of a contrast agent bolus with high temporal and spatial resolution. Methods: An EPI sequence, EPIDET (Echo Planar Imaging using Different Echo Times), was developed that allows the acquisition of different slices at different echo times. The passage of a contrast agent bolus was recorded in a slice through the large brain feeding arteries at a short echo time (TE1 = 17 ms), while brain parenchyma was imaged in up to nine additional slices at a long echo time (TE2 = 34 ms). Results: The different echo times allowed the determination of the arterial input function (signal decrease to 32%-59% of baseline intensity) and gave a sufficient signal reduction (14-22%) for reliable quantification of perfusion in brain parenchyma. Conclusions: The combination of different echo times of the DUAL-FLASH sequence and the multislice capability of EPI sequences in the EPIDET sequence enables the quantification of multi-slice perfusion examinations. Compared to the DUAL-FLASH sequence EPIDET improves spatial and temporal resolution.