囊球血管擴張術配合使用支架(PTAS)在對於治療血管狹窄症方面已有相當的療效，並且也可利用核磁共振造影(MRI)作為術前術後的評估工具。對於椎內動脈(VA)狹窄的病人，使用核磁共振的囊球擴張術成效評估是透過相位血流量化(PCFQ)去量測手術前後基底動脈(BA)的血流變化。由於病人是在手術前後兩個不同的日期進行掃描，所以病人在第二天掃描時，頭部一定會和第一次的位置有所偏差。另外在操作核磁共振儀器選擇血流分析的切面時，是透過三維飛行時間血管造影(3D TOF MRA)去手動找出基底動脈的中央位置；並且在選擇分析的血管面積時也是使用手動圈選的方式進行。這些病人本身頭部偏差和人為操作所產生的誤差會降低手術成效評估的意義性，因此我們提出使用自動切面定位及自動圈選技術以排除人為造成的誤差。透過影像定位的原理去判斷出病人於術前術後兩天頭部的移動差異量，在和第一天掃描的切面位置參數進行加總，就可計算出第二天掃描時相應的切面位置。如此一來，可更加確保術前術後掃描切麵位置的一致性，更可進一步提高整體囊球擴張術的成效評估之可靠度及意義。此外，本研究的結果也可作為判斷手術成效性的一個標準。

In order to evaluate the effect of percutaneous transluminal angioplasty with stent (PTAS) for the patients with vertebral artery stenosis, PCMRI is used to quantify the blood flow of basilar artery. In traditional flow quantification, the slice with transaction of vessel and the ROI of lumen area were manually selected. Thus, the deviation of the arterial position caused by manual selection would deteriorate the evaluation. In order to solve this problem, an automatic slice positioning method combined with automatic lumen area segmentation was proposed. Using the automatic routines, the variation caused by operator would be minimized, and then the MR evaluation of PTAS outcome could be more significant and robust. Moreover, the flow variation might only be influenced by the physiological variation and MR system error after automating the evaluation process. The reproductive study of basilar arterial flow quantification with automatic process exhibits some statistical data from eight healthy subjects without cardiac disease. Ultimately, the result of the longitudinal flow variation could be provided to be a reference for assessing the outcome of PTAS.

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