腹盆腔孤立性纤维瘤的CT和MRI表现及征象分析

目的 分析腹盆腔孤立性纤维瘤（SFT）的CT和MRI影像学表现及征象，提高对其的认识和诊断的准确性。 方法 回顾性分析2008年1月至2017年6月经手术病理证实的18例腹盆腔SFT患者[男性9例、女性9例，年龄41~71（53.0±10.6）岁]的影像学表现、临床及病理资料。18例患者中，13例行CT平扫和动态增强扫描，5例行MRI平扫和动态增强扫描，分析肿瘤的大小（最大径）、形态、密度或信号、动态增强特点、动脉期肿瘤体内血管及肿瘤周围有无血管等情况。采用卡方精确检验分析肿瘤大小、边界及形态与良恶性肿瘤的关系；Fisher检验比较三者在良恶性肿瘤中表现的差异性。 结果 ① CT影像学表现：13例患者的肿瘤直径为（10.53±6.21） cm，最大直径为2.7~23.4 cm。12例患者肿瘤的病灶边界清晰；8例呈分叶状，7例出现囊变，1例有钙化。CT动态增强扫描显示有11例呈不均匀明显强化；8例病灶内出现延迟强化区，2例表现为轻中度强化；10例动脉期病灶内显示强化血管；8例病灶周围出现迂曲血管。② MRI影像学表现：5例患者的肿瘤直径为（11.93±3.21） cm，最大直径为10.0~13.4 cm。5例患者的病灶边界均清晰；4例病灶呈分叶状；T2加权成像显示有3例出现囊变，4例病灶内见瘢痕状及片状低信号区，1例均匀等高信号；5例出现流空血管影。4例病灶表现为明显不均匀强化；4例病灶内出现延迟强化区；1例表现为均匀强化；5例动脉期在病灶内显示强化血管。③病理结果显示：18例SFT患者中，7例为恶性、11例为良性。7例恶性SFT患者中，有5例病灶最大直径超过平均直径[（10.88±5.62） cm]，而良性SFT患者中仅有2例最大直径超过平均直径，差异有统计学意义（χ2=5.103，P=0.039）。 结论 腹盆腔SFT的CT及MRI表现呈多样性，当腹腔内出现丰富的血供伴瘢痕状、片状延迟强化肿瘤，同时瘤体周围出现迂曲血管及瘤体内出现点、条状动脉期强化血管的表现有助于诊断，且MRI中T2加权成像出现低信号也具有一定的诊断价值。

CT and MRI features of solitary fibrous tumors in abdomen and pelvis

Objective To observe the CT and MRI results of solitary fibrous tumors(SFT) in the abdomen and pelvis, analyze their characteristic imaging, and improve the accuracy of diagnosis and understanding of the disease. Methods Retrospective analysis of 18 cases confirmed by pathology from January 2008 to June 2017[9 men, 9 women, age 41–71(53.0±10.6) years old] through imaging findings and clinical and pathological data of patients with pelvic SFT. Among the 18 patients, 13 received dynamic CT and 5 received dynamic MRI. The tumor size(maximum diameter), morphology, density or signal, dynamic enhancement characteristics, arterial tumor vessels, and tumors were mainly analyzed. Fisher's exact test was conducted to examine the relationship between tumor size, boundary, and morphology of benign and malignant tumors. The differences among the three characteristics in malignant tumors were determined by Fisher' s test. Results ① Characteristics of CT imaging: The maximum diameter of tumor lesions in the 13 patients with CT was(2.7–23.4) cm, and the mean diameter was(10.53±6.21) cm. Among the 13 cases, 8 were lobulated and 7 exhibited cystic degeneration. One patient showed calcification. Furthermore, 11 cases of nonuniform enhancement by dynamic enhancement was observed. Delayed enhancement was observed in 8 cases. Mild to moderate enhancement was observed in 2 cases. In 10 cases, pointy and linear enhancement of vessels could be seen at the arterial stage, and in 8 cases, tortuous vessels were observed around the lesions. The maximum diameter of the lesions was (10.0–13.4) cm and the mean diameter was(11.93±3.21) cm. ② Characteristics of MRI: The lesion boundaries of 5 patients were clear, and the lesions were lobulated in 4 of 5 patients. In T2 weighted imaging, cystic changes were observed in 3 patients. In 4 cases, scarlike or flaky low-signal areas were found in the lesions, 1 case showed uniform isobaemic signals, and 5 cases presented empty vascular shadows. Moreover, 4 cases indicated an obvious uneven enhancement. Delayed enhancement was observed in 4 cases, and uniform enhancement was observed in 1 case. In 5 cases, vessels were strengthened in the lesion at the arterial stage. ③ Pathology results showed that among the 18 SFT cases, 7 were malignant and 11 were benign. For the malignant SFT, 5 of 7 cases exceeded the average diameter[(10.88±5.62) cm], whereas for the benign SFT, only 2 of 11 cases exceeded the mean. The maximum diameter was different between the benign and malignant lesions(χ2=5.103, P=0.039), showing statistical significance. Conclusions Although radiological findings on abdomino-pelvic SFT vary between dynamic contrast enhanced CT and MRI, a hypervascular mass with delayed enhancement is the imaging feature. Peripheral tortuous vessels and filiform vessels in the lesion may reinforce the diagnosis. The low signal of T2 weighted imaging in MRI also has a certain diagnostic value.