颅底脊索瘤的MR影像研究(论动态增强扫描的意义)

MRI study of chordoma of the skull base: value of dynamic contrast enhanced scan

目的 探讨颅底脊索瘤动态增强MRI上T1WI信号的变化规律。方法 分析 15例颅底脊索瘤的MRI资料 ;测量 15例脊索瘤和 3例鼻咽癌注射钆喷替酸葡甲胺 (Gd DTPA)后 0s至 6 0～90min期间肿瘤实质同一区域各时相的T1WI信号强度 ,获取并比较两类肿瘤的动态时间 信号强度曲线。结果 颅底脊索瘤呈持续缓慢强化 ,动态时间 信号强度曲线分上升期、平台期和消退期 :0s至12～ 35min(平均 2 7min) ,信号逐渐上升至最大值 ,持续 35～ 6 6min(平均 5 0min)后逐渐下降 ,平均强化速率 10 /min ,平均下降速率 1 5 /min。鼻咽癌呈快速强化和快速消退 ,平均强化速率 32 5 /min ,平均下降速率 17/min。结论 持续缓慢强化是颅底脊索瘤的MRI影像特征 。

Objective To investigate the dynamic change of T 1WI signal intensity of chordoma of the skull base on dynamic Gd DTPA enhanced MRI Methods MRI appearances of 15 cases of chordoma of the skull base were analyzed In the 15 cases of chordoma and 3 nasopharyngeal carcinomas, a circle area in tumoral parenchyma was selected as region of interest(ROI), the T 1WI signal intensity of ROI was measured during the period from 0 to 60-90 min after contrast, and the dynamic time signal intensity curves of the two types of tumor were acquired and compared Results Slow and sustained enhancement was noticed in chordoma of the skull base, whose dynamic time signal intensity curve was composed of 3 phases: increment, plateau and decrement In the increment phase, during the first 12 to 35 minutes(mean 27 minutes), the signal intensity gradually climbed up to the maximum at the mean rate of 10/min After 35 to 66 minutes (mean 50 minutes) the signal intensity maintained in the plateau phase, the maximum started to decline at the mean rate of 1 5/min in the decrement phase In 3 cases of nasopharyngeal cancer rapid enhancement at the mean rate of 325/min and fast subsidence at the mean rate of 17/min were found without the plateau phase Conclusion The slow and sustained enhancement pattern was the MRI characteristics of chordoma of the skull base, which had differential diagnostic value