Phase-contrast MRI data of 18 Chiari-I malformation patients and 21 controls

We collected phase-contrast MRI data (5-mm midline sagittal section, rostro-caudal direction) and obtained average velocity in certain Regions-0f-Interest (ROIs). The measured ROIs are cerebellar tonsil, ventral spinal subarachnoid space, dorsal spinal subarachnoid space, upper portion of syrinxes, upper cervical cord, and medulla. Data obtained from 18 Chiari-I patients (preoperative and postoperative) and 21 controls are included. Because the preoperative MRI data was missing in one patient, the preoperative studies included 17 MRI sessions. The unit of the data is cm/sec. The data are synchronized with pre-processing so that the rise of the caudal CSF movement be placed at the center of the cardiac cycle.

Methods
We performed phase-contrast MRI on 18 patients with Chiari-I malformationc(associated with syringomyelia) and 21 controls. The MRI on the patientscwas taken before andcafter surgery (foramen magnum decompression).

Phase-contrast MRI was takn on the midline sagittal section with 5-mmcthickness. The movement in the FH (foot-head) direction was encoded withcvelocity encoding (VENC) of 10 cm/sec.

On the data of each MRI session, six regions of interest (ROIs) were placed; namely, cerebellar tonsil (tonsil), ventral subarachnoid space just below the foramen magnum (sa), dorsal subarachnoid space just below the foramen magnum (cm), the upper portion of the syrinx (syrinx), the cord segment between the fouth ventricle and the syrinx (cord), the medulla (medulla). The average flow speed inside each ROI was measured at each time point in the cardiac cycle.

The acquired data were synchronized with post-processing so that the maximal caudal velocity of 'sa' will be at the center of the data of 50 bins encompassing a cardiac cycle.