Evaluation of pleural disease using MR and CT. With special reference to malignant pleural mesothelioma

Purpose: To evaluate MR imaging and CT in differentiating malignant pleural mesothelioma from other malignancies or benign pleural disease.Material and Methods: Thirty-four patients (18 pleural mesotheliomas, 9 other malignancies, 7 benign pleural diseases) were examined using enhanced CT and MR. Two radiologists reviewed the CT and two others the MR images. Comparisons were made between the diagnostic groups and the imaging methods.Results: The abnormalities commonly found in malignant disease, but significantly less frequently in benign pleural disease, were focal thickening and enhancement of interlobar fissures. In mesothelioma, enhancement of interlobar fissures, tumour invasion of the diaphragm, mediastinal soft tissue or chest wall, were significantly more often observed than in other malignancies and MR was the most sensitive method. In other malignancies, invasion of bony structures was a more common finding and was also better shown by MR. The contrast-enhanced T1 fat-suppressed (CET1fs) sequence detected these features better than other MR sequences.Conclusion: MR, especially the CET1fs sequence in three planes, gave more information than enhanced CT. Focal thickening and enhancement of interlobar fissures were early abnormalities indicating malignant pleural disease. MR could be clinically useful for differentiating mesothelioma from other pleural diseases.     

Morphologic and functional imaging of malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is an aggressive tumor that arises from the pleura and frequently extends to adjacent structures. MPM cells produce and respond to many angiogenic factors, such as vascular endothelial growth factor (VEGF). VEGF expression in MPM is correlated with microvascular density, which is associated with poor survival. CT has been widely used as the primary imaging modality for the clinical evaluation of MPM. Major findings include nodular pleural thickening, unilateral pleural effusion, and tumor invasion of adjacent structures. CT tends to underestimate early chest wall invasion and peritoneal involvement and has well-known limitations in the evaluation of lymph node metastases. Perfusion CT can evaluate the microvasculature of tumors, while its disadvantages, such as high radiation exposure or side effects from iodinated contrast, limit its use in both research and clinical settings. MRI can provide additional information to CT. Because of its excellent contrast resolution, MRI is superior to CT, both in the differentiation of malignant from benign pleural disease, and in the assessment of chest wall and diaphragmatic involvement. Perfusion MRI is the most promising technique for the assessment of the tumor microvasculature. In MPM, therapeutic effects of chemotherapy can be monitored with perfusion MRI. It has been shown that FDG-PET is useful for the differentiation of benign from malignant lesions, for staging and monitoring metabolic response to therapy against MPM, and that it has prognostic value. An initial report on PET/CT imaging of MPM has shown increased accuracy of overall staging, improving the assessment of tumor resectability. PET/CT seems to be superior to other imaging modalities in detecting more extensive disease involvement, and identifying unsuspected occult distant metastases.     

Malignant pleural disease

The vast majority of pleural neoplasms invade the pleura secondarily and can be seen in patients with bronchogenic carcinoma, breast cancer, lymphoma, and ovarian or gastric carcinoma. Primary pleural neoplasms are less common, although they have developed notoriety since the up-surge of malignant mesothelioma and the knowledge of its connection to asbestos exposure. Other malignant primary tumors include localized fibrous tumor and pleural liposarcoma. In most patients with diffuse malignant pleural disease the chest radiograph shows pleural effusion with or without pleural thickening. Computed tomography (CT) usually provides precise localization and extent of the disease and may be of value in assessing chest wall and mediastinal involvement. In specific situations, magnetic resonance (MR) may be useful as a problem-solving tool when CT findings of chest wall or diaphragmatic invasion are equivocal or in patients with contraindication to intravenous administration of ionic contrast material.     

磁共振信号强度在胸膜疾病中的诊断意义

目的评价磁共振信号强度在胸膜疾病中的诊断价值.方法48例不同胸膜疾病病人在Philips0.5T扫描仪下行MR检查.成像常规为T1WI、T2WI快速自旋回波扫描,所有病例均在病理证实结合临床资料下得出恶性或良性胸膜疾病的诊断.恶性疾病包括胸膜间皮瘤(n=10)、胸膜转移瘤(n=18),良性疾病包括结核性胸膜炎(n=9)、胸膜肥厚(n=7)、纤维胸(n=1)、脓胸(n=2)和胸膜炎性假瘤(n=1).将各种胸膜疾病T1WI、T2WI上绝对信号强度(ASI),病灶信号与肌肉信号的对比噪声比(CNR),信号强度比(SIR)分别进行测量或计算,判断它们在良、恶性胸膜疾病之间,胸膜间皮瘤与胸膜转移瘤之间是否存在差别.结果ASI在良、恶性胸膜疾病之间,胸膜间皮瘤与转移瘤之间均无显著差异,CNR在良、恶性胸膜疾病之间于T2WI上有差别(P＜0.01),而SIR在良、恶性胸膜疾病之间于T1WI、T2WI上均有极显著差异(P＜0.001),同时,还在胸膜间皮瘤与转移瘤之间于T2WI上存在差别(P＜0.05).结论磁共振信号强度在胸膜疾病鉴别诊断中有重要意义,其中SIR最具有诊断价值.MR信号强度在T2WI上比T1WI上更具有区分不同胸膜疾病的能力.     

Staging of advanced ovarian cancer: comparison of imaging modalities--report from the Radiological Diagnostic Oncology Group

PURPOSE: To compare ultrasonography (US), magnetic resonance (MR) imaging, and computed tomography (CT) for diagnosing and staging advanced ovarian cancer. MATERIALS AND METHODS: US, CT, and MR imaging were performed in 280 patients. Images were read by three radiologists from each of the five hospitals. Image analysis included determination of malignancy within the peritoneum (11 sites), lymph nodes (10 sites), and hepatic parenchyma. The standard of reference was based on surgical and histopathologic findings. Statistical methods used were receiver operating characteristic (ROC) curve analysis, pairwise comparison of areas under the ROC curves (A(z)), analysis of sensitivity and specificity pairs, and assessment of agreement between the degree of suspicion and standard of reference. RESULTS: There were 118 patients with malignant tumors; 73 (62%) had stage III or IV disease. Metastases were found in the peritoneum in 70 (59%), nodes in 20 (17%), and liver in seven (6%) cases. In the peritoneum, MR imaging and CT (A(z) = 0.96 for both) were more accurate than US (A(z) = 0.86), especially in the subdiaphragmatic spaces and hepatic surfaces. MR imaging and CT were more sensitive than US (95%, 92%, and 69%, respectively) for peritoneal metastases. MR imaging was more accurate than CT for detection of lymph node metastases (A(z) = 0.76 vs 0.57, P =.04). In the liver, the A(z) values for the three modalities were 0.77-0.94. CONCLUSION: CT and MR imaging are equally accurate, and either modality can be used to stage advanced ovarian cancer.     

Costal pleura: appearances at high-resolution CT

The appearance of the costal pleura at high-resolution computed tomography (CT) was evaluated with a cadaver and 25 normal subjects. This was contrasted with the high-resolution CT appearance of the costal pleura in 15 patients with mild pleural thickening, 13 of whom had been exposed to asbestos. On high-resolution CT scans in the normal subjects, a 1-2-mm-thick line of soft-tissue attenuation at the point of contact between lung and chest wall represents the visceral and parietal pleura, pleural contents, endothoracic fascia, and innermost intercostal muscle. In a paravertebral location, the innermost intercostal muscle is lacking, and a thin line seen on high-resolution CT scans reflects pleura and endothoracic fascia. Transverse thoracic and subcostal muscles and extrapleural fat pads can be seen as tissue internal to a rib and may be confused with pleural thickening. In 13 of the 15 patients with mild pleural thickening, the 1-3-mm-thick pleura was separable from the underlying normal intercostal muscle by a layer of extrapleural fat. High-resolution CT was more sensitive than CT with 1-cm collimation in depicting this degree of pleural abnormality.     

Malignant pleural mesothelioma: the spectrum of manifestations on CT in 70 cases.

AIM: The aim of this pictorial review is to illustrate the spectrum of manifestations on computed tomography (CT) of malignant pleural mesothelioma. Malignant pleural mesothelioma is the most common primary neoplasm of the pleura, but nevertheless is a rare tumour. It has a strong association with previous occupational exposure to asbestos and has a bleak prognosis. MATERIALS AND METHODS: The pre-treatment CT findings of 70 patients at our institution, and the subsequent findings of the 35 patients who had follow-up CT, have been reviewed by three observers by consensus. 16 patients had surgical resections. RESULTS: The most common pre-treatment findings were pleural thickening (94%) and pleural effusions (76%). Both contraction (27%) and enlargement (10%) of the ipsilateral hemithorax were identified. Extension of disease to the chest wall, mediastinum, thoracic lymph nodes, and below the diaphragm were identified. Concurrent bilateral pleural calcification and plaques indicative of previous asbestos exposure were identified in 16% of patients. CT failed to identify chest wall and mediastinal invasion in a number of patients who underwent surgical resections. CONCLUSION: CT plays an important role in the diagnosis, assessment, and evaluation of treatment response of this tumour, although it has some limitations in specific areas in evaluating patients for surgical resection.     

CT在恶性胸膜间皮瘤诊断中的价值

目的探讨CT在恶性胸膜间皮瘤诊断中的价值。资料与方法回顾分析9年来我院经手术或/和病理证实的42例恶性胸膜间皮瘤患者的CT资料,并与12例手术所见作比较。结果结节状或肿块状胸膜增厚(97.6%)是胸膜间皮瘤最常见的CT表现,有诊断性的表现为胸膜增厚>1cm(59.5%),环状胸膜增厚(41.5%),病变累及纵隔胸膜(92.9%)或叶间裂(69.0%),病变侵犯周围胸壁或/和肋骨、纵隔、心包、膈肌等邻近组织或器官(65.9%),1例呈胸内巨大肿块,42.9%病例可见纵隔或/和肺门淋巴结肿大。在CT和手术所见的比较中,CT准确检出了13处(65%)对周围组织或器官的侵犯,漏诊7处(35%)。结论CT在恶性胸膜间皮瘤的诊断、分期上有重要价值,是治疗前的标准诊断方法。     

Detection of malignant hepatic tumors: comparison of gadolinium-and ferumoxide-enhanced MR imaging

OBJECTIVE: The purpose of our study was to compare how well gadolinium-enhanced and ferumoxide-enhanced MR imaging reveal malignant hepatic tumors. SUBJECTS AND METHODS: Both gadolinium-enhanced and ferumoxide-enhanced MR imaging were separately performed in 53 patients with a total of 87 malignant hepatic tumors (57 hepatocellular carcinomas, 28 metastases, two cholangiocarcinomas). Thirty-one of the 53 patients had hepatic cirrhosis. Images were reviewed by three independent off-site observers. Observer performance was evaluated by means of sensitivity, specificity, and receiver operating characteristic curve analyses. RESULTS: Gadolinium-enhanced MR imaging outperformed ferumoxide-enhanced MR imaging in sensitivity (81% versus 62%, p < 0.01) for malignant-tumor detection. Specificity was comparable (94%) between the two types of MR imaging. Area under receiver operating characteristic curve (A(z)) value was significantly higher with gadolinium-enhanced MR imaging than with ferumoxide-enhanced MR imaging in patients overall (A(z) = 0.896 versus 0.805, p < 0.001), in patients with cirrhosis (A(z) = 0.907 versus 0.807, p < 0.001), and in patients without cirrhosis (A(z) = 0.899 versus 0.834, p < 0.01). The superiority was enhanced in the subset of patients with cirrhosis. CONCLUSION: Gadolinium-enhanced MR imaging outperforms ferumoxide-enhanced MR imaging in revealing malignant hepatic tumors. Gadolinium-enhanced MR imaging is recommended, particularly for patients with cirrhosis.     

Incarcerated inguinal hernia from metastatic pleural mesothelioma: PET/CT imaging

PET/CT provides a comprehensive staging, post-therapeutic surveillance, and outcome prognosis of malignant pleural mesothelioma based on its hypermetabolic behavior. This ability of PET may allow the monitoring, prediction, and detection of uncommon distant gastrointestinal clinical manifestations of this disease. The authors present a case of PET/CT imaging of pleural mesothelioma disseminating to the abdomen and pelvis, inducing an incarcerated inguinal hernia.     

Imaging manifestations of pleural tumors.

Although radiologic assessment of pleural tumors may be accomplished with several imaging modalities, the standard noninvasive techniques include chest radiography and computed tomography (CT). These examinations may be supplemented with magnetic resonance imaging and occasionally with ultrasound. Depending on the location, size, and underlying histologic features, pleural tumors may produce a spectrum of findings. CT is particularly useful in defining the location and extent of these masses. The authors present a review of basic pleural anatomy and imaging features of both benign and malignant pleural neoplasms. The pleural may be involved by one of several primary or metastatic tumors. Specific cell types are diffuse malignant mesothelioma (the most common plain radiographic findings are unilateral pleural effusion and pleural thickening), localized fibrous tumor (circumscribed, spherical or ovoid, noncalcified lesions arising in the pleural surface), metastatic disease (radiographic findings may mimic those of malignant mesothelioma), and uncommon neoplasms including thymoma and lymphoma. Among these various pleural tumors, metastatic disease represents the most common neoplasm.     

Malignant pleural mesothelioma: value of CT and MR imaging in predicting resectability.

OBJECTIVE. Our objective was to determine if CT or MR imaging findings could be used to accurately predict resectability in patients with biopsy-proved malignant pleural mesotheliomas. SUBJECTS AND METHODS. CT and MR findings in 41 consecutive patients with malignant mesotheliomas who were referred to the thoracic surgery clinic for extrapleural pneumonectomy were studied by thoracic radiologists before surgery. Review of radiologic studies focused on local invasion of three separate regions: the diaphragm, chest wall, and mediastinum. Results of all imaging examinations were carefully correlated with intraoperative, gross, and microscopic pathologic findings. RESULTS. After radiologic and clinical evaluation, 34 patients (83%) had thoracotomy; 24 of these had tumors that were resectable. The sensitivity was high (> 90%) for both CT and MR in each region. Specificity, however, was low, probably because of the small number of patients with unresectable tumors. CONCLUSION. CT and MR provided similar information on resectability in most cases. Sensitivity was high for both procedures. Because CT is more widely available and used, we suggest it as the initial study when determining resectability. In difficult cases, important complementary anatomic information can be derived from MR images obtained before surgical intervention.     

Assessment of malignant pleural mesothelioma with (18)F-FDG dual-head gamma-camera coincidence imaging: comparison with histopathology.

Malignant pleural mesothelioma is an aggressive primary neoplasm for which early detection and accurate staging are known diagnostic challenges. The role of (18)F-FDG dual-head gamma-camera coincidence imaging ((18)F-FDG-CI) is yet to be defined. The purpose of this study was to evaluate the usefulness of (18)F-FDG-CI in the assessment of malignant pleural mesothelioma using histopathology as the gold standard. METHODS: Fifteen consecutive patients with CT scan evidence of pleural thickening, fluid, plaques, or calcification underwent (18)F-FDG imaging 1.5 h after the intravenous administration of 370 MBq (18)F-FDG. Imaging was performed with a dual-head gamma camera equipped with 2.54-cm-thick NaI crystals operating in coincidence mode. Using an iterative algorithm, whole-body images were reconstructed as transaxial, sagittal, and coronal images. No attenuation correction was applied. The results of (18)F-FDG-CI scans were compared with CT and with histopathologic diagnosis. RESULTS: Eleven of 15 patients had histologically proven malignant mesotheliomas (10 epithelial, 1 sarcomatoid). All 11 primary tumors were detected by (18)F-FDG, and absence of disease was confirmed in the 4 patients who were disease free. Thirty-four lesions were biopsied; among these, 29 were found to be positive for tumor. (18)F-FDG was true-positive in 28 lesions, true-negative in 4, false-negative in 1 (0.5 cm in diameter), and false-positive in 1 (inflammatory pleuritis). The smallest lesion detected was 0.8 cm. For biopsied lesions, overall sensitivity, specificity, and accuracy for (18)F-FDG-CI were 97%, 80%, and 94% respectively, compared with 83%, 80%, and 82% for CT. Twenty-one of 29 positive lesions involved the pleura, lung parenchyma, or chest wall and were all (18)F-FDG avid. In the mediastinum, (18)F-FDG-CI detected 7 of 8 biopsy-positive lesions (88%), whereas CT was positive in 6 of 8 lesions (75%). (18)F-FDG identified extrathoracic metastases in 5 patients, excluding them from surgical therapy. CONCLUSION: These preliminary results suggest that (18)F-FDG-CI appears to be an accurate method to diagnose and to define the extent of disease in patients with diffuse malignant pleural mesothelioma.     

Present and future roles of FDG-PET/CT imaging in the management of malignant pleural mesothelioma

Positron emission tomography/computed tomography (PET/CT) integrated with 2-[¹⁸F]fluoro-2-deoxy-d-glucose (¹⁸F-FDG) has emerged as a powerful tool for combined metabolic and anatomic evaluations in clinical oncologic imaging. This review discusses the utility of ¹⁸F-FDG PET/CT as a tool to manage patients with malignant pleural mesothelioma. We discuss different stages of patient management in malignant pleural mesothelioma, including diagnosis, initial staging, therapy planning, early treatment response assessment, re-staging, and prognosis.     

Preoperative staging of cervical carcinoma with MR imaging: a reappraisal of diagnostic accuracy and pitfalls

The purpose of this study was to assess the diagnostic accuracy and pitfalls of MR imaging in preoperative staging of cervical cancer. Magnetic resonance imaging was performed to determine the tumor staging for 41 patients with cervical carcinoma emphasizing tumor size, parametrial invasion, vaginal invasion, and lymph node metastases. According to the correlation of MR findings with surgical-pathological features, there was less than 5 mm discrepancy in the size in 29 of 34 tumors (85.3%) that were larger than 1 cm. In assessing parametrial invasion, vaginal invasion and lymph node metastases, MR imaging had an accuracy of 95, 83, and 86%, respectively. In determining stage of disease and differentiating operable (< or =stage IIA) from advanced disease (> or =stage IIB), MR imaging had an accuracy of 82.9 and 93%. Pitfalls leading to staging errors included difficulties in differentiating cancer foci from surrounding tissue edema and detecting microscopic tumor extension. Magnetic resonance imaging is accurate in the evaluation of parametrial invasion and differentiation of operable from advanced disease. The ability of MR imaging to detect microscopic extra-cervical tumor extension and differentiate cancer foci from surrounding tissue edema is not as reliable.     

青年细支气管肺泡癌X线平片及CT表现分析

目的:研究青年细支气管肺泡癌的胸片与CT表现特征性和病理学发生基础及临床特点,提高对该病诊断认识水平。方法:回顾性对比分析24例。经纤支镜,穿刺活检,手术病理证实的细支气管肺泡癌的胸片及CT表现以及转移灶的特征表现,探讨各型病变的影像学特征。结果:根据大体病理及相对影像上病变形态和分布特点,可将细支气管肺泡癌分为孤立结节型5例占21%,多发结节型11例占46%,弥漫型8例占33%。其中孤立结节型相对特异型征象较多,如分叶征,支气管充气征,胸膜凹陷征;多发结节型;胸片表现为两肺中下叶棉球样征象,但CT显示为两肺弥漫多发结节状,碎路石征象,常伴有胸膜牵拉等征象;弥漫粟粒型:两肺中下叶呈粟粒样改变,部分病例有融合,实变现象,临床上易误诊为粟粒型肺结核,转移瘤或肺炎等疾病。另外,细支气管肺泡癌骨骼转移灶呈浸润性破坏,分布较广,以肋骨和锁骨侵犯为多见。结论:细支气管肺泡癌的影像表现复杂多样,对各型的征象表现进行深入细致地分析,结合临床特点,可提高对本病的诊断符合率。     

Asbestos-related pleural disease: value of dedicated magnetic resonance imaging techniques

OBJECTIVES: We sought to compare respiratory-gated high-spatial resolution magnetic resonance imaging (MRI) and radial MRI with ultra-short echo times with computed tomography (CT) in the diagnosis of asbestos-related pleural disease. METHODS: Twenty-one patients with confirmed long-term asbestos exposure were examined with a CT and a 1.5-T MR unit. High-resolution respiratory-gated T2w turbo-spin-echo (TSE), breath-hold T1w TSE, and contrast-enhanced fat-suppressed breath-hold T1w TSE images with an inplane resolution of less than 1 mm were acquired. To visualize pleural plaques with a short T2* time, a pulse sequence with radial k-space-sampling was used (TE = 0.5 milliseconds) before and after administration of Gd-DTPA. CT and MR images were assessed by 4 readers for the number and calcification of plaques, extension of pleural fibrosis, extrapleural fat, detection of mesothelioma and its infiltration into adjacent tissues, and detection of pleural effusion. Observer agreement was studied with the use of kappa statistics. RESULTS: The MRI protocol allowed for differentiation between normal pleura and pleura with plaques. Interobserver agreement was comparable for MRI and CT in detecting pleural plaques (median kappa = 0.72 for MRI and 0.73 for CT) and significantly higher with CT than with MRI for detection of plaque calcification (median kappa 0.86 for CT and 0.72 for MRI; P = 0.03). Median sensitivity of MRI was 88% for detection of plaque calcification compared with CT. For assessment of pleural thickening, pleural effusion, and extrapleural fat, interobserver agreement with MRI was significantly higher than with CT (median kappa 0.71 and 0.23 for pleural thickening, 0.87 and 0.62 for pleural effusion, and 0.7 and 0.56 for extrapleural fat, respectively; P < 0.05). For detection of mesothelioma, median kappa was 0.63 for MRI and 0.58 for CT. CONCLUSION: High-resolution MR sequences and radial MRI achieve a comparable interobserver agreement in detecting pleural plaques and even a higher interobserver agreement in assessing pleural thickening, pleural effusion, and extrapleural fat when compared with CT.     

MR staging of clinical stage I and IIa cervical carcinoma: a reappraisal of efficacy and pitfalls

The purpose of this study was to evaluate the diagnostic efficacy and pitfalls of magnetic resonance (MR) imaging in preoperative staging of cervical cancer. MR imaging was performed to determine the tumor staging for 31 patients with cervical carcinoma emphasizing tumor size, parametrial invasion, vaginal invasion and lymph node metastases. Tumor size was 3.23+/-1.75 cm (mean+/-standard deviation) at MR imaging compared with 2.79+/-1.76 cm at surgical-pathologic evaluation. The discrepancy between the tumor size determined by MR imaging and the measured surgical specimens was consistent in tumors larger than 1 cm. In assessing parametrial invasion, vaginal invasion and lymph node metastases, MR imaging had an accuracy of 96.7 and 87%. In determining stage of disease and differentiating operable (< or =stage IIA) from advanced disease (> or =stage IIB), MR imaging had an accuracy of 83.8 and 96.7%. Pitfalls leading to staging errors included difficulties in differentiating cancer foci from surrounding tissue edema and excluding vaginal invasion in the presence of large cervical cancer. In conclusion, MR imaging is accurate in the evaluation of parametrial invasion and useful in the differentiation of operable from advanced disease. The ability of MR imaging to exclude vaginal invasion in the presence of large cervical cancer and differentiate cancer foci from surrounding tissue edema is not as reliable.     

MRI在良、恶性胸膜肿瘤鉴别诊断中的价值

目的：探讨磁共振成像在良、恶性胸膜肿瘤鉴别诊断中的作用。方法：对45例胸膜肿瘤患者（良性8例,恶性37例）进行了CT和MRI检查。评估分析良、恶性胸膜肿瘤的CT和MRI形态学特点及其分别在T1WI、T2WI和增强T1WI上的信号特点。结果：在CT图像上,共出现弥漫性胸膜增厚30例（恶性29例,良性1例）,纵隔胸膜受累28例（恶性27例,良性1例）、环绕或不规则胸膜增厚23例（恶性22例,良性1例）,胸壁或膈肌浸润9例（全部为恶性）;在MRI上,共出现弥漫性胸膜增厚32例（恶性31例,良性1例）,纵隔胸膜受累29例（恶性27例,良性2例）、环绕或不规则胸膜增厚24例（恶性23例,良性1例）,胸壁或膈肌浸润1例（全部为恶性）。根据前述形态学特点,CT与MRI对诊断胸膜恶性肿瘤总的敏感性分别为83．8％和86．5％,总特异性均为62．5％。结论形态学及信号特点,MRI对诊断良、恶性肿瘤病变的敏感性为97．3％,特异性为100％。结论：单纯依据其形态学特点,MRI对胸膜肿瘤的发现与诊断价值与CT相仿。但当MR信号与形态学特点结合时,其对良、恶性胸膜肿瘤的鉴别诊断价值则明显优于CT。