A Preliminary Study On The Ability Of 3D-ASL To Localize The Epileptogenic Zone During Interictal Period Of Epilepsy

Objective To study the changes of epileptogenic zone perfusion in epileptic patients in interictal period,and to initially explore the ability of three-dimensional arterial spin labeling(3D-ASL)imaging technology to locate the epileptic region laterally.Materials and methods We collected epilepsy patients in the database of our hospital from September 2017 to December 2019.Forty patients was included.Follow-up was performed every three months after operation,until 24 months,and the shortest follow-up time was half a year.Postoperative outcome according to the2017 International Anti-Epilepsy Coalition(ILAE)postoperative effect classification:29 cases with satisfactory postoperative results were included in the follow-up evaluation of Eagle gradeⅠorⅡ.29 patients with a clear epileptogenic zone underwent high resolution T2FLAIR,T2WI propeller,DWI,3D-ASL,3D Bravo T1WI.The post labeling delay(PLD)time of the 3D-ASL scan is 1525ms.A total of29 healthy control groups were collected.The ASL pseudo-color image and 3D Bravo T1WI volume imaging were fused with post-processing software and the region of??interest(ROI)was manually hooked to measure the cerebral blood flow(CBF)value.The ROI area was about??30-60mm~2.All the participants were measured the epilepsy side,contralateral side of the bilateral cortex and cortex-medullary junction and white matter.The CBF value is expressed as mean±standard deviation.Paired t test was used to compare the bilateral CBF values??in the two groups.The independent sample t test was used for comparison between the two groups.The difference is statistically significant with P<0.05.Receiver operating characteristic(ROC)curve was used to analysis on statistically significant CBF values??with area under curve(AUC),threshold,sensitivity and specificity,and further diagnostic effectiveness of the threshold using paired chi-square test.Paired chi-square test was used to compare the diagnostic ability of3D-ASL and MR high resolution images in epileptogenic zone.Results The CBF value of the cortico-medullary junction in the epileptogenic zone of the case group was significantly lower than that of the contralateral side(P<0.05),but the CBF value of the epileptogenic zone and the contralateral cortex and white matter in the case group had no significant difference(P>0.05).The CBF value of the cortical and cortico-medullary junction on the side of the epileptogenic zone in the case group was significantly higher than that in the control group(P<0.05),and the CBF value in the mirror side of the epileptogenic zone was significantly higher than that in the control group(P<0.05).The CBF threshold at the junction of cortex and cortico-medulla was generally consistent in the diagnosis of epileptogenic zone(χ~2=0.506,P<0.001).The positive rate of CBF threshold diagnosis at the dermis-medullary junction was 75.9%,which was higher than that of cortical CBF threshold diagnosis(72.4%),and the difference was statistically significant(P=0.003).The consistency of 3D-ASL and MR high resolution images in the localization of epileptogenic zone was general(χ~2=0.512,P<0.001).The positive rate of location diagnosis of epileptogenic zone by ASL was 82.8%,which was higher than that of MR high-resolution image(72.4%),and the difference was statistically significant(P=0.004).Conclusion There is abnormal perfusion in the epileptogenic zone during the interictal period in epilepsy patients,which can be qualitatively evaluated by3D-ASL technology.It is concluded that the low perfusion at the junction of the cortex and medulla in the epileptogenic zone is of significance for the localization of the epileptogenic zone.The CBF values of epileptic cortex and cortico-medullary junction in epilepsy patients during interictal period are different from those in healthy subjects,which can be quantitatively evaluated by 3D-ASL technique.Compared with MR high-resolution images,3D-ASL can improve the location of epileptogenic zone during interictal period,which can assist the preoperative localization of epileptogenic zone.