Dear Safal Khanal Sir,ASL MRI has been validated against other quantitative technologies such as Dynamic Susceptibility-Weighted Contrast-Enhanced MRI, PET scan, and using different exogenous contrast agents. Furthermore, since ASL image contrast is not based on susceptibility effects, it could be used to study regions of high static field inhomogeneity. This property of ASL is especially valuable while imaging highly layered structures such as the eye’s retina.ASL implementations are now commercially available on all major MRI platforms and their reproducibility has been confirmed by several multicentre studies. However, before applying this technique in the clinic, many of its technical parameters have to be studied and optimized. Here we are going to review the effects of a number of these factors on the quality of the ASL measurements.

Also you should note that The retinal circulation has no autonomic innervation and is regulated by local factors while the choroidal circulation is not autoregulated and is mainly controlled by sympathetic innervation. Using a 9 T Phillips magnet in a preliminary study, we have previously shown that ASL can be applied to image this nonregulated blood flow in the retina. 

Hi Christo. Many thanks for the update. Would love to go through the paper if it is available.