Application of Postlabeling Delay Time in 3-Dimensional Pseudocontinuous Arterial Spin-Labeled Perfusion Imaging in Normal Children

Objective To explore the application value of postlabeling delay (PLD) in 3D pseudocontinuous arterial spin-labeled (3D-pcASL) perfusion imaging in normal children and to find the optimal PLD values for children at each age group. Methods Five groups of children, with 50 patients in each group, who underwent routine magnetic resonance imaging scans with normal results were included. The patients were stratified according to the following ages: younger than 1 month, more than 1 month to 6 months, more than 6 months to 12 months, more than 1 year to 3 years, more than 3 years to 6 years, and more than 6 years to 18 years. All patients received 3D-pcASL perfusion magnetic resonance scanning. The PLD values were set to 1025, 1525, or 2025 milliseconds. In subjective evaluations, the signal-to-noise ratio (SNR) and cerebral blood flow (CBF) of 3D-pcASL perfusion images under different PLD values were compared and analyzed. Results For patients in the 1-month to 6-month group, the images were mainly grade A when the PLD value was 1025 milliseconds, which equaled 43 and 46 cases, respectively. The brain CBF values and SNR values were higher than those of the images with PLD values of 1525 and 2025 milliseconds. For patients in the >6-month to 12-month group, >1-year to 3-year group, >3-year to 6-year group, and >6-year to 18-year group, the images were mainly grade A when the PLD value was 1525 milliseconds, which equaled 43, 45, 43, and 46 cases, respectively. The brain CBF values and SNR values were higher than those of the images with PLD values of 1025 and 2025 milliseconds. Conclusions The optimal PLD values for 3D-pcASL perfusion imaging are different in children of different ages. The optimal PLD value for infants who are 6 months younger is 1025 milliseconds. The optimal PLD value for children older than 6 months to 18 years is 1525 milliseconds.