Background and Aim: flow-sensitive MRI techniques have been applied to quantitatively and qualitatively assess CSF flow dynamics to discriminate between communicating and non-communicating hydrocephalus. So, we aimed to Correlate between thin cuts T2 ,3D- heavy T2 {CISS, sampling perfection with application-optimized contrasts using different flip angle evolutions (SPACE) with variable flip angle mode (VFAM) & constant angle} & phase contrast (PC) Sequences in pediatric hydrocephalus Patient & methods :20 Patients with age below 18yrs old with evidence of hydrocephalic changes by clinical examination and by previous U/S,CT or MR scan with ventriculomegaly were included. 2D-T2-TSE, 3D-heavy T2 & PC-MRI were analyzed qualitatively by evaluating the capabilities of visualization of the obstructive pathology, overall image quality, severity of artifacts, and delineation of the CSF pathways. Results: showed that 3D heavily T2WI were superior to T2-TSE, 3D-SPACE showed fewer artifacts than 3D-CISS or T2-TSE sequences. 3D-SPACE VFAM is considered as a highly accurate alternative to PC-MRI for physiological and morphological evaluation of aqueductal patency compared to T2-TSE. Conclusion: 3D heavily T2 sequences are necessary for the assessment of CSF pathways in patients with hydrocephalus when compared with T2-TSE. 3D-SPACE VFAM is considered as a highly accurate alternative to PC-MRI for physiological and morphological evaluation of aqueductal patency. Key words: Hydrocephalus, 3D-SPACE, variable flip angle, phase contrast. Abbreviations: CSF; Cerebrospinal fluid, CISS; Constructive interference in steady state, SPACE; sampling perfection with application optimised contrasts using different flip angle evolutions, VFAM; variable flip angle mode, TSE; Turbo spin echo, PC; phase contrast.