MSCT对胸腺上皮肿瘤WHO简化病理分型的鉴别诊断价值

目的探讨多层螺旋CT(MSCT)对低危型、高危型胸腺瘤及胸腺癌的鉴别诊断价值。方法回顾性分析经病理(穿刺或手术)证实的67例胸腺上皮肿瘤,基于WHO病理分型简化为低危型胸腺瘤、高危型胸腺瘤及胸腺癌三组,并对其CT征象进行统计分析。结果67例TETs中,低危型胸腺瘤30例(A型3例、AB型20例、B1型7例),高危型胸腺瘤22例(B2型11例、B3型11例),胸腺癌15例。高危型胸腺瘤、胸腺癌较低危型胸腺瘤易表现为边缘分叶或不规则(P均<0.05)及易出现对心包侵犯(P均<0.05);胸腺癌较低危型胸腺瘤易出现增强后密度不均、囊变坏死及胸膜转移(P均≤0.003);胸腺癌较低危型、高危型胸腺瘤易出现纵隔淋巴结肿大(P均≤0.002);纵隔大血管侵犯在三组间两两比较均有统计学差异(P均<0.05)。结论MSCT对TETs的WHO简化病理分型鉴别诊断具有重要价值。     

MSCT在鉴别≤3cm的低、高风险胸腺瘤及胸腺癌中的价值

目的 探讨多层螺旋CT(MSCT)对最大径≤3 cm的胸腺上皮肿瘤(TET)诊断价值.方法 回顾性分析56例经病理证实的最大径≤3 cm的TET病例的病理、影像学资料,根据WHO 2004标准进行组织学分型,将病例分为低风险胸腺瘤组(A/AB/B1型)、高风险胸腺瘤组(B2/B3型)、胸腺癌组(C型),分析各组TET的CT征象,包括病灶的形状、边缘是否光滑、是否伴有棘状突起、是否伴有瘤周小结节、强化程度、胸膜侵犯征象、周围脂肪间隙等.各类型间比较采用χ2检验,样本量过小时,采用Fisher精确试验.结果 低风险胸腺瘤(27例)较高风险胸腺瘤(23例)及胸腺癌(6例)更常表现为规则的类圆形的形态(χ2=73,P<0.001;χ2=116,P<0.001),纵隔-肺界面更易呈膨隆状(χ2=3.41,P=0.046;χ2=7.39,P=0.01);高风险胸腺瘤、胸腺癌较低风险胸腺瘤更常见边缘模糊、棘状突起、胸膜侵犯等征象(P<0.001);胸腺癌较高风险胸腺瘤更常见边缘模糊、棘状突起、胸膜侵犯等征象(χ2=11.5,P=0.009);B2型胸腺瘤与胸腺癌之间的差异有显著性意义(χ2=31.52,P<0.001),然而B3型胸腺瘤与胸腺癌之间无统计学差异(χ2=6.96,P=0.07).结论 MSCT可准确显示病灶的形态、边缘、瘤周情况、强化程度及胸膜侵犯情况,在一定程度上可预测胸腺瘤的组织学分型,可为术前诊断及预后评估提供依据.     

18F-FDG PET/CT of thymic epithelial tumors: usefulness for distinguishing and staging tumor subgroups.

The purpose of our study was to assess the usefulness of integrated PET/CT using 18F-FDG for distinguishing thymic epithelial tumors according to the World Health Organization (WHO) classification. METHODS: Thirty-three patients (age range, 34-68 y; mean age, 54.6 y) with thymic epithelial tumors, who underwent both integrated PET/CT and enhanced CT, were included. The clinicopathologic stages, maximum standardized uptake values (SUVs), and uptake patterns of tumors on integrated PET/CT images, and various enhanced CT findings, are described according to the simplified (low-risk [types A, AB, and B1] and high-risk [types B2 and B3] thymomas and thymic carcinomas) subgroups of the WHO classification. Discriminant analysis was performed to determine the relative capabilities of integrated PET/CT and enhanced CT findings to differentiate tumor subgroups. RESULTS: Tumors included 8 low-risk thymomas, 9 high-risk thymomas, and 16 thymic carcinomas. The maximum SUVs of high-risk thymomas (P < 0.001) and low-risk thymomas (P < 0.001) were found to be significantly lower than those of thymic carcinomas. Homogeneous 18F-FDG uptake within tumors was more frequently seen in thymic carcinomas than in high-risk thymomas (P = 0.027) or low-risk thymomas (P = 0.001). The uptake pattern (homogeneous vs. heterogeneous) on integrated PET/CT images and the presence of mediastinal fat invasion on enhanced CT images were found to be useful for differentiating tumor subgroups. In addition, integrated PET/CT helped detect lymph node metastases, which were not identified on enhanced CT in 2 patients. CONCLUSION: Integrated PET/CT was found to be useful for differentiating subgroups of thymic epithelial tumors and for staging the extent of the disease.     

Does CT of thymic epithelial tumors enable us to differentiate histologic subtypes and predict prognosis?

OBJECTIVE: The aims of our study were to describe the CT findings of thymic epithelial tumors and to correlate these findings with the histopathologic subtypes and prognosis. MATERIALS AND METHODS: The CT findings of thymic epithelial tumors were analyzed in 91 patients who had undergone surgery between May 1995 and June 2002. Two observers, who were unaware of the histopathologic classification made in accordance with World Health Organization (WHO) recommendations and the prognosis of the tumors, retrospectively reviewed the initial CT findings in terms of the contours and shapes of the tumors and the presence of necrosis, calcification, mediastinal fat or great vessel invasion, pleural seeding, contrast enhancement, and lymph node enlargement. These findings were compared with the simplified subgroups of WHO histologic classification (low-risk thymomas [types A, AB, and B1], high-risk thymomas [types B2 and B3], and thymic carcinomas [type C]) and with postoperative recurrence. RESULTS: The study found 31 low-risk thymomas (eight type A, 16 type AB, and seven type B1 tumors), 45 high-risk thymomas (25 type B2 and 20 type B3), and 15 thymic carcinomas (type C). Lobulated contour was more often seen in high-risk thymomas (26/45, 58%; p = 0.0456) and thymic carcinomas (10/15, 67%; p = 0.033) than in low-risk thymomas (9/31, 29%). Mediastinal fat invasion was more often seen in thymic carcinomas (5/15, 33%; p = 0.0133) than in low-risk thymomas (1/31, 3%). Great vessel invasion was seen only in thymic carcinomas (2/15, 13%; p = 0.0244). Tumors with a lobulated or irregular contour, an oval shape, mediastinal fat or great vessel invasion, and pleural seeding showed significantly more frequent recurrence and metastasis (all, p < 0.05). CONCLUSION: Although CT is of limited value in differentiating histologic subtypes according to the WHO classification, CT findings may serve as predictors of postoperative recurrence or metastasis for the thymic epithelial tumors.     

MR imaging of thymic epithelial tumors: correlation with World Health Organization classification

Purpose The aim of this study was to determine magnetic resonance imaging (MRI) features of various subtypes of thymic epithelial tumors based on the World Health Organization classification. Materials and methods The study included 64 patients with histologically proven thymic epithelial tumors. Two observers evaluated the MRI findings in terms of tumor size, contour, lobulation, shape, homogeneity, the presence of intratumor high- and low-signal foci, enhancement degree and pattern, the presence of capsule and septum, and associated mediastinal lymphadenopathy and pleural effusion. Results Type A tumors were more likely to have a smooth contour, round shape, distinct capsule, and smaller size compared to any other type of thymic epithelial tumor. Thymic carcinomas demonstrated a higher prevalence of low-signal foci within the mass on T2-weighted images and mediastinal lymphadenopathy than any other types. The frequency of heterogeneous intensity on T2-weighted images increased from type A tumors to thymic carcinomas. Conclusion The presence of a smooth contour, round shape, and capsule is highly suggestive of a type A tumor. Foci of low signal intensity in the mass on T2-weighted images and mediastinal lymphadenopathy are highly suggestive of thymic carcinomas.     

Computed tomography and magnetic resonance imaging of mediastinal tumors

We describe the clinical, pathological, and imaging findings of mediastinal tumors with focus on thymic hyperplasia, thymic epithelial tumors, and germ cell tumors, malignant lymphoma, and various cystic masses. Chemical shift magnetic resonance imaging (MRI) is useful in characterization of the normal thymus and differentiation of hyperplastic thymus and thymic tumors. In contrast to noninvasive thymomas, invasive thymomas and thymic carcinomas show a more aggressive growth pattern. Local invasion and pleural spread are characteristic of invasive thymoma and mediastinal lymphadenopathy and distant metastasis suggest thymic carcinomas. Mature teratoma typically shows various computed tomography (CT) attenuation, and MR signal intensity depending on its contents and fat tissue and bone within the lesions are its characteristic findings. Seminomas typically have homogenous internal CT attenuation and MR signal intensity with minimal contrast enhancement. Nonseminomatous malignant germ cell tumors characteristically show prominent internal degenerative changes and invasion to the adjacent structures. In mediastinal lymphomas, a residual mass is common after treatment and MRI provides important information in distinguishing viable tumors from residual benign masses. Some mediastinal cysts may reveal high attenuation similar to solid lesions on CT depending on their contents and MRI can be useful in the differentiation of cystic masses from solid lesions.     

胸腺上皮性肿瘤18F-FDG PET/CT显像最大标准化摄取值与WHO病理分型及Masaoka分期的关系

目的 探讨胸腺上皮性肿瘤（TET）术前18F-FDG PET/CT显像最大标准化摄取值（SUV_max）与世界卫生组织（WHO）病理分型及Masaoka分期的关系。 方法 回顾性分析2007年9月至2019年3月于南京医科大学第一附属医院经手术病理学结果证实的40例TET患者的临床资料，其中男性14例、女性26例，年龄32~79岁。分析所有患者的术前18F-FDG PET/CT显像资料，测定病灶的SUV_max。参照WHO(2015) TET病理分型将TET患者分为低危型胸腺瘤（A、AB、B1型）、高危型胸腺瘤（B2、B3型）和胸腺癌（C型）3组；采用Masaoka分期标准将TET患者分为Ⅰ期、Ⅱ期和Ⅲ期 3组；将TET患者分为胸腺瘤（包括低危型胸腺瘤和高危型胸腺瘤）和胸腺癌2组，采用受试者工作特征（ROC）曲线计算SUV_max和曲线下面积（AUC）。3组间的比较采用Kruskal-Wallis秩和检验，2组间的比较采用 Mann-Whitney U检验。 结果 低危型胸腺瘤11例（A型1例、AB型4例、B1型6例），高危型胸腺瘤15例（B2型10例、B3型5例），胸腺癌14例。Masaoka分期:Ⅰ期8例，Ⅱ期17例，Ⅲ期15例。低危型胸腺瘤、高危型胸腺瘤和胸腺癌的中位SUV_max分别为3.78、5.21和10.44，3组间SUV_max的差异有统计学意义（χ2=26.716，P<0.01）；组间的两两比较差异均有统计学意义（Z=3.088、?3.928、4.106，均P<0.01）。Ⅰ期、Ⅱ期、Ⅲ期的中位SUV_max分别为3.74、5.14、10.08，3组间SUV_max的差异有统计学意义（χ2=22.295，P<0.01），组间的两两比较差异均有统计学意义（Z=2.680、3.679、?3.644，均P<0.01）。ROC曲线分析结果:AUC为0.953（95%可变区间:0.891~1.000，P<0.01）；SUV_max=6.81是鉴别诊断胸腺瘤与胸腺癌的最佳临界值。 结论 18F-FDG PET/CT 的参数SUV_max与TET的WHO病理分型及Masaoka分期具有较好的相关性，可为临床制定治疗计划提供参考。     

MR imaging of thymoma--comparison with CT, operative, and pathological findings]

Twenty-six patients with thymoma, who had magnetic resonance (MR) imaging and computed tomography (CT) before surgery, were studied. Twenty-six thymomas were classified into 11 non-invasive thymomas (Masaoka's clinical stage I) and 15 invasive thymomas (stage II, III, and IV). On MR imaging compared with histological findings, low signal intensity rim of the tumor was corresponded to fibrous capsule of the tumor, and linear and/or reticular low signal intensity lines in the tumor were corresponded to the fibrous septae dividing thymoma into lobules. The detectability of these findings by MR imaging was superior to that by CT. Margin of the tumor was smooth in non-invasive thymoma rather than invasive thymoma. The diagnostic accuracy of invasion to vessel, and pleura or lung on MR imaging and CT was compared with operative and histological findings. MR imaging was same as CT in its ability to detect tumoral invasion to vessel, and slightly superior to pleura or lung. In conclusion MR images clearly show the findings corresponding to pathologic specimens, and MR imaging combining with CT is useful to differentiate non-invasive thymoma to invasive thymoma.     

18F-FDG PET/CT Evaluation of Thymomas: a Pictorial Review

The World Health Organization classification divides thymomas according to morphology, epithelial component, and cell atypia. They are grouped into 3 large subgroups: low-risk thymomas (types A, AB, and B1), high-risk thymomas (types B2 and B3), and thymic carcinomas. Tumor subtype represents an independent prognostic factor, which determines therapeutic decision. All thymomas show some degree of ¹⁸F-FDG uptake, which tends to increase with the grade of malignancy; this is related to glucose transporter 1 (GLUT1) expression. This review collects all types of thymomas with illustrative images and provides a guide to get familiar with histological characteristics of the lesions and have them in mind because, even imaging findings can overlap among subtypes, certain characteristics can be combined to make an accurate diagnosis based on ¹⁸F-FDG PET-CT findings.     

18F-FDG PET/CT is Useful for Pretreatment Assessment of the Histopathologic Type of Thymic Epithelial Tumors

Purpose

This study was performed to assess the usefulness of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) or PET/computed tomography (CT) for distinguishing thymic epithelial tumors according to World Health Organization (WHO) classifications.

Methods

We analyzed a total of 45 patients (range, 29–75 years of age; mean, 55 years) with pathologically confirmed thymic epithelial tumors who underwent pretreatment ¹⁸F-FDG PET or PET/CT between November 2003 and October 2009. The size, visual grading of uptake value, peak standardized uptake value (SUVpeak), uptake pattern, and contour of each tumor, and associated findings on PET or PET/CT, were analyzed relative to the three simplified WHO subgroups: less-invasive thymomas (types A and AB), more-invasive thymomas (types B1, B2, and B3) and thymic carcinomas. We statistically assessed the relationship of ¹⁸F-FDG PET or PET/CT findings with these simplified subgroups.

Results

Of the 45 patients, ten had less-invasive thymomas, 23 had more-invasive thymomas, and 12 had thymic carcinomas. The SUVpeak of the less- and more-invasive thymomas were significantly lower than those of thymic carcinomas (p < 0.000), but there was no difference in SUVpeak between less- and more-invasive thymomas. The visual grading scale (p < 0.000), uptake pattern (p = 0.001), and contour (p < 0.000) of the tumors differed significantly among the three simplified subgroups.

Conclusion

The image findings of ¹⁸F-FDG PET or PET/CT differed significantly by histologic subgroups. Pre-treatment evaluation with ¹⁸F-FDG PET or PET/CT might be helpful in differentiating subgroups of thymic epithelial tumors.     

Extrahepatic abdominal imaging in patients with malignancy: comparison of MR imaging and helical CT, with subsequent surgical correlation

PURPOSE: To compare state-of-the-art magnetic resonance (MR) imaging with single-phase helical computed tomography (CT) in abdominal screening for extrahepatic disease in patients with proved malignancy. MATERIALS AND METHODS: Fifty-seven patients with known malignancy underwent abdominal contrast material-enhanced helical CT and MR imaging from 1994 through 1997. Prospective interpretations of CT scans and MR images were used to assess each modality's sensitivity in depicting malignant extrahepatic tumor at 17 anatomic sites. Imaging findings were compared with surgical results in all patients. RESULTS: Helical CT depicted 101 (66%) of 154 surgically confirmed extrahepatic tumor sites; MR imaging depicted 139 (90%) (P < .001). MR imaging depicted tumor in more patients at 11 of the 17 anatomic sites; at six sites, MR imaging and helical CT were equivalent. MR imaging showed significantly greater depiction of extrahepatic tumor for the peritoneum (P < .05), bowel (P < .01), and mesentery (P < .05). False-negative interpretations would have altered patient care had the extrahepatic tumor remained undetected in 13 patients for helical CT and in six patients for MR imaging. CONCLUSION: State-of-the-art MR imaging can be used for effective abdominal screening for extrahepatic tumor in patients with malignancy. Compared with single-phase helical CT, MR imaging depicted more sites of extrahepatic tumor and was particularly advantageous for the peritoneum, mesentery, and bowel.     

Traumatic neuroma and recurrent lymphadenopathy after neck dissection: comparison of radiologic features

PURPOSE: To retrospectively evaluate the ultrasonographic (US), computed tomographic (CT), and magnetic resonance (MR) imaging features that differentiate traumatic neuroma from recurrent lymphadenopathy after neck dissection. MATERIALS AND METHODS: Imaging findings of 10 patients with a traumatic neuroma and 17 with recurrent lymphadenopathy were reviewed. US and CT were performed in all patients; MR imaging was performed in 16 patients. Findings analyzed at US included the diameter of the long and short axes, the short-axis-to-long-axis ratio, and the presence of a central hyperechoic area. Findings analyzed at CT were contiguity with common or internal carotid artery, lesion location in correlation with carotid artery, and the presence of a hyperattenuating rim. Findings analyzed at MR imaging included signal intensity on T1- and T2-weighted images, the presence of ring enhancement, and the presence of a hypointense rim on T2-weighted images. RESULTS: Statistically significant differences were found between traumatic neuroma and recurrent lymphadenopathy in the short-axis-to-long-axis ratio (mean, 0.47 vs 0.72; P < .001), the short-axis diameter (mean, 5.7 vs 12.2 mm; P < .001), the presence of a central hyperechoic area (five of 10 patients [50%] vs one of 17 patients [6%]; P < .05), the frequency of contact with carotid artery (two of 10 patients [20%] vs 13 of 17 patients [76%]; P < .01), and the presence of a hypointense rim on T2-weighted MR images (three of six patients [50%] vs zero of 10 patients [0%]; P < .05). Findings in other parameters were not statistically significant. CONCLUSION: Several imaging findings can differentiate traumatic neuroma from recurrent lymphadenopathy after neck dissection.     

Malignant thymic epithelial tumors: CT-pathologic correlation

OBJECTIVE: The purpose of our study was to describe and compare the CT and pathologic findings of atypical thymoma and thymic carcinoma. MATERIALS AND METHODS: Twenty-seven consecutive patients (14 men, 13 women ranging in age from 22 to 77 years [mean age, 52 years]) with pathologically proven atypical thymoma (n = 9) and thymic carcinoma (n = 18) constituted the study population. The chest CT findings in each of the 27 patients were reviewed retrospectively in consensus by two chest radiologists. These findings were correlated with pathologic findings. RESULTS: The tumors were located in the anterior mediastinum, and most tumors had a lobulated margin (24/27, 89%). Atypical thymomas were significantly smaller (mean, 4.7 cm) than thymic carcinomas (mean, 7.2 cm) (p = 0.041) on CT. The findings of invasion of the great vessels, lymph node enlargement, extrathymic metastases, and phrenic nerve palsy were seen only in patients with thymic carcinoma. The frequencies of necrosis, intratumoral calcification, pleural effusion, pleural implants, pericardial effusion, and obliteration of the mediastinal fat plane were not significantly different between atypical thymomas and thymic carcinomas (p > 0.05). Various histologic subtypes were included in thymic carcinoma. The tumor necrosis and calcification seen on CT were confirmed at pathologic examination. CONCLUSION: When a large thymic tumor appears with invasion of the great vessels, lymph node enlargement, phrenic nerve palsy, or extrathymic metastases on CT, thymic carcinoma rather than atypical thymoma should be considered.     

囊性肾癌的超声与CT诊断及鉴别诊断

目的:探讨超声及CT对囊性肾癌的诊断价值。方法:回顾性分析经手术和病例证实的25例囊性肾癌的超声及CT表现。结果:依据各种不同的影像学表现将囊性肾癌分为:单房囊肿型,多房囊肿型,附隔、壁结节型和囊实混合型四类。其特点为:囊壁及囊内间隔局部不规则增厚或附有实性结节,以囊性为主的囊实性肿块;增厚的囊壁、间隔或附壁结节内可见强化。结论:超声及CT检查对囊性肾癌的诊断与鉴别诊断具有一定的临床实用价值。     

Acinic cell carcinoma of the head and neck: radiologic-pathologic correlation

OBJECTIVE: To describe and correlate the imaging and pathologic findings of acinic cell carcinoma (ACC) in the head and neck. METHODS: We reviewed the radiologic findings of 12 patients with pathologically proven ACC in the head and neck. They were 6 males and 6 females (ages: 5-75 years, mean 36 years) who undergoing computed tomography (CT, n=9) and CT with magnetic resonance (MR) imaging (n=3). RESULTS: The lesions in the superficial lobe of the parotid gland were solid (n=7), cystic (n=1), and cystic mass with mural nodule (n=1) on CT. A parapharyngeal lesion was cystic mass with mural nodule, and a submandibular and a palate tumor were cystic lesions on CT. All solid masses in the parotid gland (n=7) included focal low-attenuating portions on CT, which were microcyst, hemorrhage, or necrosis on pathologic examination. We could not find intratumoral calcifications or metastatic lymphadenopathy on imaging and histologic studies in all 12 cases. Internal hemorrhage on the MR images was seen in a parapharyngeal and a parotid lesion. CONCLUSION: Although ACC appears to have nonspecific imaging findings, familiarity with some imaging features can be helpful for differential diagnosis of head and neck tumors.     

The CT findings of pancreatic acinar cell carcinoma in five cases

ObjectivesThe aim of this study is to analyze the computed tomographic (CT) findings of pancreatic acinar cell carcinoma (ACC).Materials and methodsThe CT features and clinical presentations of five patients (four men, one woman; mean age, 52 years) with pathology-proven pancreatic ACC were reviewed. The image characteristics included the lesion location and size, the exophytic nature of the tumor, intratumoral hemorrhage, calcification, the presence of cystic or necrotic components, bile or pancreatic duct dilation, attenuation on the noncontrast image, attenuation on the arterial- and venous-phase images, peripancreatic invasion, peripancreatic lymphadenopathy, and distant metastases.ResultsThe tumors were located at the pancreatic tail in three cases and at the pancreatic head in two cases. The average lesion size was 5.3 cm. Exophytic features and cystic/necrotic components were found in 80% (4/5) and 60% (3/5) of cases, respectively. The ACC showed a mild hypodense appearance on noncontrast CT in 100% (3/3) of cases and a hypodense appearance on arterial-/venous-phase CT in 80% (4/5) of cases. The exception was one lesion that showed a significantly hyperdense appearance and a mildly hyperdense appearance on the arterial- and venous-phase images. None of the CT images showed enhancement of a capsule, calcification, intratumoral hemorrhage, bile or pancreatic duct dilation, vascular encasement, or distant metastatic disease, but three cases showed peripancreatic invasion and lymphadenopathy.ConclusionsWith persistent mild enhancement, the typical ACC appears as an exophytic tumor with a focal cystic/necrotic component and the lack of ductal dilatation. The predilection for older male patients and elevated serum alpha fetoprotein are useful clinical features for confirming an ACC diagnosis.     

胸腺上皮肿瘤WHO病理分型与CT特征的相关性

目的：探讨胸腺上皮性肿瘤（TETs）的WHO病理分型与CT表现的相关性,以提高其CT诊断及临床诊疗水平。方法：回顾性分析经穿刺活检或手术病理证实的66例TETs患者的CT影像学表现。所有患者均行胸部CT平扫及增强扫描,均经组织病理学及细胞免疫组化检查并进行WHO组织病理分型,分析TETs各种组织学类型的CT特征。结果：66例TETs中男39例,女27例,年龄6～77岁。病理分型：A型5例（7．6％）,AB型15例（22．7％）,B1型13例（19．7％）,B2型10例（15．2％）,B3型10例（15．2％）及胸腺癌13例（19．7％）。A、AB、B1型胸腺瘤均呈圆形或类圆形,而80．0％的B3型胸腺瘤及92．3％的胸腺癌呈不规则形;大部分（92．4％）胸腺肿瘤呈中度强化。80．0％B3型胸腺瘤及100％胸腺癌有包膜破坏并侵犯邻近结构;40．0％的B3型胸腺瘤及61．5％的胸腺癌出现心包和（或）胸膜腔积液;随着肿瘤病理分级的增加,周围结构受侵的发生率亦随之升高,分别为15．4％（B1）、40．0％（B2）、80．0％（B3）及100％（胸腺癌）。TETs组织学分类与侵袭危险度CT分级之间存在显著相关性（rs=0．736,P〈0．01）。结论：不同WHO病理分型的TETs的cT表现具有一定特征性,TETs的CT特征反映了其侵袭危险性及组织病理学分型。     

Thymic hyperplasia and thymus gland tumors: differentiation with chemical shift MR imaging

PURPOSE: To prospectively evaluate chemical shift magnetic resonance (MR) imaging for differentiating thymic hyperplasia from tumors of the thymus gland. MATERIALS AND METHODS: The institutional review board approved this study; informed consent was obtained and patient confidentiality was protected. The authors assessed 41 patients (17 male, 24 female; age range, 16-78 years) in whom thymic lesions were seen at chest computed tomography. Patients were assigned to a hyperplasia group (n=23) (18 patients with hyperplastic thymus associated with Graves disease and five with rebound thymic hyperplasia) and a tumor group (n=18) (seven patients with thymomas, four with invasive thymomas, five with thymic cancers, and two with malignant lymphomas). T2-weighted fast spin-echo and T1-weighted in-phase and opposed-phase MR images were obtained in all patients and visually assessed. A chemical shift ratio (CSR), determined by comparing the signal intensity of the thymus gland with that of the paraspinal muscle, was calculated for quantitative analysis. Mean CSRs for the patient groups and subgroups were analyzed by using Welch t and Newman-Keuls tests. P<.05 indicated a significant difference. RESULTS: The thymus gland had homogeneous signal intensity in all 23 patients in the hyperplasia group and in 12 of the 18 patients in the tumor group. The mean CSR (+/- standard deviation) was 0.614 +/- 0.130 in the hyperplasia group and 1.026 +/- 0.039 in the tumor group. Mean CSRs in the patients with a hyperplastic thymus and Graves disease, rebound thymic hyperplasia, thymoma, invasive thymoma, thymic cancer, and malignant lymphoma were 0.594 +/- 0.120, 0.688 +/- 0.154, 1.033 +/- 0.043, 1.036 +/- 0.040, 1.020 +/- 0.044, and 0.997 +/- 0.010, respectively. The difference in CSR between the hyperplasia and tumor groups was significant (P<.001). Mean CSRs in the hyperplasia subgroups were lower than those in the tumor subgroups (P<.001). All hyperplasia group patients had an apparent decrease in thymus gland signal intensity at chemical shift MR imaging; no tumor group patients had a decrease in thymus gland signal intensity. CONCLUSION: Chemical shift MR imaging can be used to differentiate thymic hyperplasia from thymic tumors.     

Invasion of laryngeal cartilage by cancer: comparison of CT and MR imaging

Forty-two patients with laryngeal carcinomas were examined with computed tomography (CT) and magnetic resonance (MR) imaging. The accuracy of both CT and MR imaging in the depiction of cartilage invasion was evaluated in 16 patients by comparing findings at CT and MR with pathologic findings. Calcified cartilage that has been invaded by cancer is frequently seen on CT scans as having an intact contour. Tumor approaching nonossified cartilage may simulate cartilage invasion. On T1-weighted MR images, invaded marrow of ossified cartilage is of intermediate signal intensity, allowing it to be differentiated from normal bone marrow. On proton-density images, tumor is of increased signal intensity, which allows it to be differentiated from nonossified cartilage. In our experience, the specificities of CT and MR imaging were approximately equal (91% and 88%, respectively), but CT had a considerably lower sensitivity than MR (46% vs. 89%). Gross movement artifacts, which resulted in nondiagnostic images, occurred in 16% of the MR examinations. MR imaging is recommended as the modality of choice in the diagnosis of cartilage invasion.     

Retroperitoneal neurilemoma: CT and MR findings.

OBJECTIVE. Our objective was to characterize the CT and MR imaging findings of retroperitoneal neurilemomas. MATERIALS AND METHODS. We reviewed the CT and MR imaging findings in six women with retroperitoneal neurilemomas. RESULTS. Retroperitoneal neurilemomas were round, 5-13 cm in diameter, and located in the presacral pelvic retroperitoneum in four patients and adjacent to the kidney in two patients. CT findings of the tumors were well-demarcated round masses showing prominent cystic changes and oriented in a somewhat radial fashion. Medium and heavily T2-weighted MR images showed high-intensity necrotic areas and nonnecrotic areas of various signal intensity. CONCLUSION. CT findings of a round mass with prominent cystic degeneration, along with certain MR imaging characteristics, may be helpful in the preoperative diagnosis of retroperitoneal neurilemomas.