Tanaka Y O, Yoshizako T, Nishida M, Yamaguchi M, Sugimura K, Itai Y
Department of Radiology, Institute of Clinical Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan.
AJR Am J Roentgenol. 2000 Nov;175(5):1423-30. doi: 10.2214/ajr.175.5.1751423.
Various types of malignancy can develop in patients with endometriosis. Enhancing mural nodules have been reported as an imaging characteristic of malignant transformations. We evaluated contrast-enhanced MR imaging to determine the optimum sequence to reveal mural nodules and other characteristics of malignant transformations.
We examined 10 patients with pathologically proven ovarian adenocarcinoma in endometriosis and 10 patients (the control group) with ovarian endometrioma suggestive of malignant transformation on the basis of sonographic findings. We analyzed the size and nature of the endometriomas in each patient. We compared four types of contrast-enhanced MR imaging to determine which sequence best revealed mural nodules.
In the malignant and control groups, 80% of the cysts with findings suggestive of malignant transformation showed unilateral disease or larger endometrial cysts on the suggestive side than on the contralateral side. High signal intensity on T1-weighted images and low signal intensity on T2-weighted images relative to the myometrium were observed only in two of 10 malignant endometrial cysts and in all control cysts. All malignant endometriomas had small mural nodules with low signal intensity on T1-weighted contrast-enhanced images. Only three benign endometriomas had mural nodules and none of them enhanced. The enhancement of mural nodules was easily seen on dynamic subtraction imaging.
On the basis of our findings, endometrial cysts with malignant transformation rarely show low signal intensity on T2-weighted images and usually have enhancing mural nodules. Because the enhancement of mural nodules is often difficult to evaluate on conventional T1-weighted images, dynamic subtraction imaging can be valuable.
子宫内膜异位症患者可发生多种类型的恶性肿瘤。壁结节强化已被报道为恶性转化的影像学特征。我们评估了对比增强磁共振成像，以确定显示壁结节和恶性转化其他特征的最佳序列。
我们检查了10例经病理证实患有子宫内膜异位症相关卵巢腺癌的患者以及10例根据超声检查结果提示有恶性转化可能的卵巢子宫内膜瘤患者（对照组）。我们分析了每位患者子宫内膜瘤的大小和性质。我们比较了四种对比增强磁共振成像类型，以确定哪种序列最能清晰显示壁结节。
在恶性组和对照组中，80%提示有恶性转化的囊肿表现为单侧病变，或提示侧的子宫内膜囊肿比另一侧更大。相对于子宫肌层，仅在10个恶性子宫内膜囊肿中的2个以及所有对照囊肿中观察到T1加权图像上的高信号强度和T2加权图像上的低信号强度。所有恶性子宫内膜瘤在T1加权对比增强图像上均有小的低信号强度壁结节。只有3个良性子宫内膜瘤有壁结节，且均无强化。壁结节的强化在动态减影成像上很容易观察到。
根据我们的研究结果，发生恶性转化的子宫内膜囊肿在T2加权图像上很少表现为低信号强度，且通常有强化的壁结节。由于在传统T1加权图像上往往难以评估壁结节的强化情况，动态减影成像可能具有重要价值。
