Sadohara Junko, Fujimoto Kiminori, Müller Nestor L, Kato Seiya, Takamori Shinzo, Ohkuma Kazuaki, Terasaki Hiroshi, Hayabuchi Naofumi
Department of Radiology, Kurume University School of Medicine, 67 Asahi-Machi, Kurume, Fukuoka, Japan.
Eur J Radiol. 2006 Oct;60(1):70-9. doi: 10.1016/j.ejrad.2006.05.003.
To assess the CT and magnetic resonance (MR) imaging findings of thymic epithelial tumors classified according to the current World Health Organization (WHO) histologic classification and to determine useful findings in differentiating the main subtypes.
Sixty patients with thymic epithelial tumor who underwent both CT and MR imaging were reviewed retrospectively. All cases were classified according to the 2004 WHO classification. The following findings were assessed in each case on both CT and MRI: size of tumor, contour, perimeter of capsule; homogeneity, presence of septum, hemorrhage, necrotic or cystic component within tumor; presence of mediastinal lymphadenopathy, pleural effusion, and great vessel invasion. These imaging characteristics of 30 low-risk thymomas (4 type A, 12 type AB, and 14 type B1), 18 high-risk thymomas (11 type B2 and seven type B3), and 12 thymic carcinomas on CT and MR imaging were compared using the chi-square test. Comparison between CT and MR findings was performed by using McNemar test.
On both CT and MR imaging, thymic carcinomas were more likely to have irregular contours (P < .001), necrotic or cystic component (P < .05), heterogeneous contrast-enhancement (P < .05), lymphadenopathy (P < .0001), and great vessel invasion (P < .001) than low-risk and high-risk thymomas. On MR imaging, the findings of almost complete capsule, septum, and homogenous enhancement were more commonly seen in low-risk thymomas than high-risk thymomas and thymic carcinomas (P < .05). MR imaging was superior to CT in the depiction of capsule, septum, or hemorrhage within tumor (all comparison, P < .05).
The presence of irregular contour, necrotic or cystic component, heterogeneous enhancement, lymphadenopathy, and great vessel invasion on CT or MR imaging are strongly suggestive of thymic carcinomas. On MR imaging, the findings of contour, capsule, septum, and homogenous enhancement are helpful in distinguishing low-risk thymomas from high-risk thymomas and thymic carcinomas.
根据世界卫生组织（WHO）当前的组织学分类，评估胸腺上皮肿瘤的CT和磁共振（MR）成像表现，并确定区分主要亚型的有用表现。
回顾性分析60例接受CT和MR成像检查的胸腺上皮肿瘤患者。所有病例均按照2004年WHO分类进行分类。在CT和MRI上对每个病例评估以下表现：肿瘤大小、轮廓、包膜周长；均匀性、间隔的存在、出血、肿瘤内坏死或囊性成分；纵隔淋巴结肿大、胸腔积液和大血管侵犯的存在。使用卡方检验比较30例低风险胸腺瘤（4例A型、12例AB型和14例B1型）、18例高风险胸腺瘤（11例B2型和7例B3型）以及12例胸腺癌在CT和MR成像上的这些影像学特征。使用McNemar检验进行CT和MR表现之间的比较。
在CT和MR成像上，胸腺癌比低风险和高风险胸腺瘤更易出现不规则轮廓（P <.001）、坏死或囊性成分（P <.05）、不均匀强化（P <.05）、淋巴结肿大（P <.0001）和大血管侵犯（P <.001）。在MR成像上，低风险胸腺瘤比高风险胸腺瘤和胸腺癌更常见几乎完整的包膜、间隔和均匀强化的表现（P <.05）。在显示肿瘤内的包膜、间隔或出血方面，MR成像优于CT（所有比较，P <.05）。
CT或MR成像上出现不规则轮廓、坏死或囊性成分、不均匀强化、淋巴结肿大和大血管侵犯强烈提示胸腺癌。在MR成像上，轮廓、包膜、间隔和均匀强化的表现有助于区分低风险胸腺瘤与高风险胸腺瘤和胸腺癌。
