Bennett G L, Petersein A, Mayo-Smith W W, Hahn P F, Schima W, Saini S
Department of Diagnostic Imaging, Brown University School of Medicine, Rhode Island Hospital, Providence 02903, USA.
AJR Am J Roentgenol. 2000 Feb;174(2):477-85. doi: 10.2214/ajr.174.2.1740477.
The purpose of this study was to determine whether the addition of gadolinium-enhanced imaging to heavily T2-weighted MR imaging of the liver is valuable in differentiating hemangiomas from metastases. The T2 relaxation time was also included in our analysis.
Fifty-one patients with 52 proven liver lesions (24 hemangiomas and 28 metastases) larger than 1 cm underwent MR imaging at 1.5 T with T2-weighted spin-echo (TR/TE, 3000/80, 160) and gadolinium chelate-enhanced dynamic T1-weighted gradient-recalled echo (80/2.6, 80) pulse sequences. Images were reviewed by observers who were unaware of the patients' clinical history; first, only T2-weighted images were reviewed and then T2-weighted plus dynamic images were reviewed together. The T2 relaxation times were calculated for each lesion. Diagnostic accuracy by each method was compared using receiver operating characteristic analysis.
Mean T2 relaxation times were 76 +/- 26 msec for metastases and 133 +/- 25 msec for hemangiomas. The addition of dynamic scanning to the T2-weighted sequence made a statistically significant difference for only one observer (p = 0.03). However, it did not make a statistically significant contribution for either observer when compared with the T2 relaxation time. Although addition of the dynamic images resulted in correct diagnosis of six lesions, three lesions were misdiagnosed after having been correctly characterized on the T2-weighted images alone.
When optimized T2-weighted images are obtained and the T2 relaxation time is calculated, routine use of gadolinium enhancement for differentiation of hemangiomas from metastases is unnecessary although dynamic scanning is valuable in selected cases.
本研究旨在确定在肝脏的重T2加权磁共振成像中添加钆增强成像对于区分肝血管瘤和转移瘤是否有价值。我们的分析中还纳入了T2弛豫时间。
51例患者有52个经证实的肝脏病变（24个肝血管瘤和28个转移瘤），病变直径大于1 cm，均在1.5 T下接受磁共振成像检查，采用T2加权自旋回波序列（TR/TE，3000/80, 160）和钆螯合物增强动态T1加权梯度回波序列（80/2.6, 80）。由不了解患者临床病史的观察者对图像进行评估；首先，仅评估T2加权图像，然后将T2加权图像和动态图像一起评估。计算每个病变的T2弛豫时间。使用受试者操作特征分析比较每种方法的诊断准确性。
转移瘤的平均T2弛豫时间为76±26毫秒，肝血管瘤为133±25毫秒。对于仅一名观察者而言，在T2加权序列上添加动态扫描产生了统计学上的显著差异（p = 0.03）。然而，与T2弛豫时间相比，对于任何一名观察者而言，动态扫描均未产生统计学上的显著贡献。尽管添加动态图像后正确诊断了6个病变，但有3个病变在仅T2加权图像上被正确诊断后却被误诊。
当获得优化的T2加权图像并计算T2弛豫时间时，常规使用钆增强来区分肝血管瘤和转移瘤是不必要的，尽管动态扫描在某些特定病例中是有价值的。
