在頸動脈的非顯影劑磁振血管攝影(non-contrast enhance MRA)中，常用的掃描波序為TOF (time of flight)及PC(phase contrast)，但其仍受到複雜血流影響或掃描時間過長的限制，在頸動脈分叉處更容易出現因訊號喪失所產生的假性狹窄，雖然顯影劑磁振血管攝影(contrast enhance MRA)常成為臨床檢查的替代方式，但對於腎功能異常或顯影劑過敏體質者，仍造成潛在的醫療危險，因此希望以Time-SLIP (Time-Spatial Labeling Inversion Pulse)的新技術搭配3D True-SSFP (True-steady-state free-precession)波序，在不需施打顯影劑下，能夠呈現頸動脈的血管影像，藉由進行Time-SLIP 的參數最佳化，找出適合的TI(inversion time)值，並與傳統TOF 影像進行比較，評估其影像品質是否能成為頸動脈臨床檢查的另一項選擇。

For non-contrast enhance MR angiography (MRA) of the carotid arteries, the most commonly used pulse sequences are time of flight (TOF) and phase contrast (PC). However, there is still limitation due to complex hemodynamics of the carotid arteries, and prolonged scanning time. At the carotid bifurcation, signal loss frequently results in an imaging feature of pseudostenosis. In such condition, contrast enhanced MRA is an alternative way in clinical practice. However, for those with renal function impairment or allergy to contrast medium, contrast administration is associated with potential risk.
Therefore, in our institution, a novel technique called Time-Spatial Labeling Inversion Pulse (Time-SLIP) combined with 3 dimensional true-state free-precession (3D True-SSFP) was applied to achieve images for vasculature detail of the carotid artery without injection of contrast medium. In our study, the optimal parameters for Time-SLIP are tested to find out the best inversion time (TI) value. The imaging quality of Time-SLIP was compared with that of conventional TOF, to evaluate if it can provide another imaging of choice in the clinical application of carotid artery examination.