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。     

MR imaging of the chest: Mediastinum and chest wall

This review presents the options and limitations of MRI in non-vascular diseases of the mediastinum and the chest wall. In numerous thoracic pathologies, MRI is a useful supplement to spiral CT. This imaging procedure also allows a contrast-media-free differentiation of solid tumors and vascular lesions (e. g., aortic aneurysms). The advantages of MRI over CT are particularly useful when multiplanar tumor imaging is required prior to surgery to establish the exact spatial relationship between tumor and the other mediastinal structures. Primary indications for MRI in diseases of the mediastinum and chest wall are therefore: (a) tumors of the posterior mediastinum for determining their position in relation to the neural foramina and the spinal canal; (b) chest wall tumors; (c) preoperative multiplanar imaging of primary mediastinal tumors; and (d) contraindications against CT exams with iodine contrast media.     

US in the diagnosis of pediatric chest diseases.

Most pediatric chest diseases are adequately evaluated with chest radiography. However, when chest radiography does not allow identification of the location and nature of an area of increased opacity, ultrasonography (US) can help establish the diagnosis. US may be helpful in evaluation of persistent or unusual areas of increased opacity in the peripheral lung, pleural abnormalities, and mediastinal widening; US is particularly useful in patients with complete opacification of a hemithorax at radiography. In cases of pulmonary parenchymal lesions, identification of air or fluid bronchograms at US and of pulmonary vessels at color flow imaging is useful for differentiating pulmonary consolidation or atelectasis from lung masses and pleural lesions. US allows characterization of pleural fluid collections as simple, complicated, or fibroadhesive, which is important information for planning thoracentesis or thoracotomy. Computed tomography and magnetic resonance imaging are superior to US in evaluation of the mediastinum, but US is a reasonable alternative in certain situations (eg, to avoid unnecessary investigation of a normal thymus simulating a mediastinal mass). In cases of chest wall lesions, US may enable localization of the site of origin to soft tissues or an extrapleural intrathoracic location. Osseous involvement, particularly rib involvement, is easily evaluated with US.     

Reconstruction of the sternum and chest wall with methyl methacrylate: CT and MRI appearance

The aim of our study was to define the appearance of methyl methacrylate grafts replacing resected sternum and ribs on CT and MRI and how the sternal graft may mimic an abnormally sclerotic sternum on CT images. We reviewed the CT scans of nine patients who had undergone chest wall resection (eight with malignant and one with benign disease) and reconstruction with a composite of methyl methacrylate and Marlex mesh graft. One of them had an MRI study as well. The size, shape and CT attenuation were assessed on mediastinal and bone window settings. The sternal graft was seen on mediastinal and even better on bone windows as an abnormally wide, irregularly shaped structure, somewhat denser than the normal sternum. The chest wall prosthesis replacing resected ribs was seen as a continuous dense structure and of similar attenuation as that of the sternal graft. On MRI the prosthesis appeared as a well-defined structure with no signal. Reconstruction of the chest wall with methyl methacrylate appears on CT as a diffusely dense sclerotic bone lesion not unlike a malignant lesion. The possibility of a graft has to be included in the differential diagnosis in these cases. Received 8 January 1997; Revision received 23 May 1997; Accepted 4 July 1997     

儿童纵隔神经母细胞瘤的CT与MRI诊断

目的 探讨儿童纵隔神经母细胞瘤的CT与MRI表现及其诊断价值.方法 回顾性分析21例经病理证实的儿童纵隔神经母细胞瘤的CT和MRI表现.19例行CT检查,8例行MRI检查.结果 20例肿瘤位于后纵隔,呈椭圆形或不规则形软组织肿块,突向肺野,边界较清楚.CT平扫示肿瘤密度较均匀12例,密度不均匀7例,15例肿瘤内伴有钙化.13例行增强检查,7例均匀强化,6例不均匀强化.8例MRI检查T1WI示肿瘤呈等或稍低信号,与胸壁肌肉相近,T2 WI呈不均匀稍高信号,3例肿瘤内伴出血、囊变呈混杂信号.结论 儿童患者,CT或MRI检查发现后纵隔肿物,特别是其内伴钙化者,诊断时应首先考虑神经母细胞瘤.     

儿童胸壁病变的影像表现与临床分析

目的 探讨儿童胸壁病变的临床及影像表现特点，提高对胸壁病变的诊断水平。方法 收集我院2009年10月-2018年6月经手术及病理证实的50例胸壁病变患儿，包括感染组（4例）和非感染组（46例），非感染组进一步分为良性肿瘤组（41例）和恶性肿瘤组（5例）。50例患儿均行超声、CT或MRI检查。对所有病例的临床及影像表现进行回顾性分析。结果 3组病例的临床及影像表现各有不同。①临床表现：感染组病人全部出现发热、胸痛、病灶局部红肿热的临床表现，且病变均质软；良性肿瘤组中质软出现率为90.2%（37/41）；恶性肿瘤组全部病变均质韧。3组病变移动性均差。感染组及恶性肿瘤组全部病例均有局部压痛，而良性肿瘤组压痛的发生率仅为7.3%（3/41）。②影像表现：良性肿瘤组中，75.6%（31/41）病变显示内部均匀，65.9%（27/41）边缘清晰；而感染组及恶性肿瘤组病灶内部不均匀，边缘模糊。良性肿瘤组中仅9.8%（4/41）病灶可见钙化，2.4%（1/41）病灶有出血，19.5%（8/41）病灶内部出现囊腔影，14.6%（6/41）病例可见肋骨破坏；恶性肿瘤组全部侵犯入胸腔并破坏肋骨；感染组均无肋骨破坏。感染组与恶性肿瘤组病变均呈明显强化，而良性肿瘤组中80.5%（33/41）表现为无/轻度强化。结论 不同性质胸壁病变临床特点各异，结合临床和影像特征可更好地诊断胸壁病变。     

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.     

Magnetic resonance imaging in the evaluation of lung cancer

MRI is used most efficaciously in the evaluation of patients with bronchogenic carcinoma when employed as a tailored examination designed to answer specific questions relevant to patient management. CT continues to be used more generally in staging lung cancer when imaging beyond conventional chest radiography is required. Specific areas in which MRI can provide important and unique information (which may supplement a CT study) include the following: (1) evaluation of the local extent of superior sulcus tumors, and (2) distinction between stage IIIA (resectable) and stage IIIB (unresectable) tumors. Confirmation of tumor invasion of major mediastinal structures is necessary before depriving a patient of potential curative resection. MRI may contribute important information when CT findings are indefinite, particularly with regard to invasion of major cardiovascular structures (eg, superior vena cava, pulmonary artery, pericardium, and heart); invasion of the tracheal carina or bilateral involvement of main bronchi; and the presence of contralateral mediastinal or hilar lymphadenopathy. MRI should be considered as a primary imaging modality to evaluate central tumors in patients for whom intravenous contrast agents are contraindicated, and as a problem-solving modality when CT is inconclusive in the detection of a possible hilar or mediastinal mass. Other specific applications of MRI include the identification of tumor recurrence in the presence of radiation fibrosis, assessment of the extent of chest wall invasion of peripheral lung tumors, and the noninvasive characterization of adrenal masses. The scope of these MRI applications in patients with lung cancer may expand in the future with refinements in motion suppression techniques, implementation of ultrafast MRI (using variations of the echoplanar method), and further development of MRI spectroscopy and MRI contrast agents.     

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.     

CT of focal pulmonary masses in childhood.

Focal pulmonary masses in children encompass a spectrum of conditions including congenital lesions, inflammatory masses, hematomas, and benign and malignant tumors. Congenital masses include bronchial atresia, sequestration, cystic adenomatoid malformation, and pulmonary vascular anomalies. Inflammatory masses most commonly result from infection and include pulmonary abscess, granulomas, and postinflammatory pseudotumors. Blunt trauma can cause a hematoma, which decreases in size on serial radiographs. Pulmonary neoplasms may be benign such as papilloma, hamartoma, and bronchial carcinoid tumor (low-grade malignancy), or they may be malignant as in sarcoma, carcinoma, and pulmonary blastoma. Because computed tomography (CT) is the most sensitive technique in detecting and helping characterize parenchymal disease, it has become the procedure of choice for further investigation of lesions seen or suggested on plain chest radiographs. Understanding the CT appearance of these lesions can allow an accurate diagnosis and optimize management of the patient's condition.     

背部弹力纤维瘤的 CT 和 MRI 诊断

目的：探讨背部弹力纤维瘤(EFD)的 CT 和 MRI 表现及其诊断价值,提高对 EFD 的认识。方法回顾性分析经手术病理证实的20例(36个病灶)EFD 患者的 CT 或 MRI 图像,其中12例行胸部 CT 平扫,4例行胸部 MRI 平扫,4例行肩部 MRI 平扫,分析其 CT 及 MRI 表现特点。结果①EFD 发病部位均位于肩胛骨内侧前锯肌与胸壁间的脂肪间隙内,表现为扁平椭圆状或半圆形的软组织肿块,与肌肉密度(信号)相似,内均见沿病灶长轴分布的脂肪密度(信号)间隔;病灶边缘不规整,病灶外侧与前锯肌和肩胛骨交界部分界不清,脂肪间隙消失。②EFD 男女性发病率、单双侧发病率及左右侧病灶大小差异均有统计学意义(P <0.05),其中女性发病率及双侧发病率较高,以右侧病灶较大。结论①EFD 发病部位固定,影像学表现特殊,CT 及 MRI 检查可明确诊断。②肩胛骨与胸壁之间的机械性摩擦可能是肿瘤生长的协同因素。     

椎旁原始神经外胚层瘤CT和MRI诊断

目的:研究椎旁外周性原始神经外胚层瘤(pPNET)的CT及MR表现,提高对该病的认识。方法:报道5例经手术病理证实的pPNET的临床、CT、MRI及组织学所见,并复习相关文献。结果:5例均见单侧椎旁肿块,累及椎管内硬膜外,肋骨骨质侵蚀,胸髓受压变形;CT显示肿块形态不规则、密度均匀;MRI示T1WI肿块信号均匀、略高于邻近骨骼肌信号,T2WI呈不均匀高信号,增强后肿块明显均匀强化。术后MRI显示局部肿块复发和胸腔积液,CT发现肺部、纵隔多发转移结节。结论:pPNET为少见的起源于胸壁、椎旁的恶性肿瘤,其CT、MRI表现无特征性,但可明确肿瘤的范围、进行手术切除可能性评估及治疗后随访。CT易显示肋骨、椎体骨质破坏、肺部小转移灶,MRI则可显示胸壁受累、胸髓受压变形的程度和范围等。     

肺部肿块性病变的能谱CT诊断价值

目的:探讨能谱CT成像对肺部肿块性病变的诊断与鉴别诊断价值。方法:回顾性分析59例肺部肿块患者的临床及影像资料,其中良性肿块22例,恶性37例。患者均行能谱CT扫描,得到动脉期和静脉期能谱曲线40~140keV区间能量水平的CT值及碘基图、水基图,并行数据分析。结果:动脉期和静脉期40~140keV能量水平CT值中,40~80keV区间的CT值良性肿块组均低于恶性肿块组,单能量越低时CT值差别越大;动脉期和静脉期碘基图上良性肿块组的碘浓度均低于恶性肿块组,差异有统计学意义(P0.05);动脉期和静脉期良性肿块组和恶性肿块组的水基值相比,差异无统计学意义(P0.05)。结论:不同性质肺部肿块在能谱成像上碘含量不同,可用以初步区分肺部良性和恶性肿块病变。     

Diagnostic imaging of mediastinal masses in children.

Mediastinal masses are the most common thoracic masses in children. The encyclopedic list of diagnostic considerations can be distilled into a concise and practical differential diagnosis based on the location of the mass and the established prevalence of various tumors and pseudotumors in the mediastinal compartments. Malignant lymphoma, benign thymic enlargement, teratomas, foregut cysts, and neurogenic tumors make up 80% of mediastinal masses in children. Continuing advances in imaging technology have altered traditional approaches to the evaluation and diagnosis of mediastinal masses in children. Plain chest radiography remains the basic imaging examination to define location and morphology. Cross-sectional imaging subsequently clarifies the morphology and extent of the mass. In general, CT is the primary cross-sectional imaging procedure in the evaluation of most mediastinal masses in children. Exceptions to this rule include MR in children with posterior mediastinal masses or suspected vascular lesions: in such cases, MR imaging is the preferred initial postradiographic examination. Sonographic examination may be diagnostic in foregut cysts and some other mediastinal masses. Gallium-67 scintigraphy has an emerging role in management of malignant lymphoma.     

CT and MRT in mediastinal and hilar space-occupying lesions

Thirty-eight patients with mediastinal and/or hilar masses were imaged by computed tomography (CT) and magnetic resonance imaging (MRI). Results were analyzed retrospectively regarding the ability to demonstrate the masses, their number, size, definition, location and tissue characteristics. CT and MRI showed equivalent results in 32 cases; additional information was obtained in two patients by CT, in four patients by MRI. In view of the specific advantages and limitations of both CT and MRI we believed that in patients with mediastinal and/or hilar masses, contrast enhanced CT remains the procedure of choice after performing plain chest radiographs; in certain cases MRI will prove useful for further evaluation.     

The anterior mediastinum: anatomy and imaging procedures

The mediastinum is divided into compartments (anterior, middle, posterior) on the basis of lateral chest radiographs. Several anatomical and radiological classifications of the mediastinum are reported in the literature. Most mediastinal abnormalities are initially suspected following chest radiography; the need for further investigation and the most appropriate imaging modality are largely dictated by the tentative diagnosis made on this examination. Although routine chest radiography initiates the evaluation of mediastinal disorders, it is rarely diagnostic: notable exceptions are teeth or bones within a mass, which are diagnostic of a teratoma; air/fluid levels suggest an oesophageal origin, hernia, cyst, or abscess. Chest radiography is followed by spiral computed tomography (sCT). However, even sCT with contrast material is occasionally diagnostic (a confident diagnosis can be made of some lesions such as mature teratoma and mediastinal goiter) but is usually sufficient for preoperative evaluation before mediastinotomy or mediastinoscopy: it is instrumental in planning further diagnostic workup. In certain cases, magnetic resonance imaging (MRI) may be complementary to sCT, but its use is not considered routine. Besides, although the anterior mediastinum is suitable for sonographic examination, the diagnostic value of ultrasonography has not been fully exploited. Thyroid scanning with radioactive iodine is useful in identifying and evaluating masses of suspected thyroid origin. The role of fluorodeoxyglucose positron emission tomography (FDG-PET) in mediastinal diseases continues to be evaluated: it has potential for differentiating between benign and malignant disease and is expected to play a more extensive role in the imaging of mediastinal neoplasms in the future. In this paper, the radiological features of masses located in the anterior mediastinum are discussed, with particular reference to radiographic and CT patterns useful to the clinician's everyday practice.     

Diagnostic value of MR imaging in comparison to CT in the detection and differential diagnosis of renal masses: ROC analysis

The aim of this work was to compare MR imaging and CT in the detection of renal masses and in the differential diagnosis between benign and malignant lesions. In 33 patients with 54 renal lesions CT and MR images were evaluated by four readers with regard to tumor detection and characterization using a receiver-operating-characteristics (ROC) analysis. The MRI protocol consisted of a T1-weighted spin-echo (SE) sequence (TR/TE: 300/10 ms) before and after contrast administration and a heavily T2-weighted turbo-SE (TSE) sequence (TR/TE: 5500/150 ms). A_z values for the area under the ROC curves for lesion detection were 0.92 ± 0.04 for CT and 0.91 ± 0.05 for MRI, respectively, which was not statistically different. The MRI technique was slightly, but not significantly, better than CT in the overall characterization (accuracy in differentiation between benign and malignant) of renal lesions with an A_z value of 0.90 ± 0.05 compared with 0.88 ± 0.06 for CT. The MRI technique proved to be statistically superior to CT (p < 0.01) in the correct characterization of benign renal lesions. MRI equals CT in the overall detection and differential diagnosis of renal masses. MRI is very helpful for further differential diagnosis of lesions which are equivocal on CT especially in the differentiation between complicated cysts and cystic or hypovascular renal cell carcinoma. Received 29 April 1996; Revision received 14 August 1996; Accepted 2 September 1996     

False-positive CT and thallium-201 SPECT results in a patient with suspected lung cancer and mediastinal lymph node metastasis

We describe a patient with a final diagnosis of inflammatory change in which combined imaging results were strongly suggestive of lung cancer with mediastinal lymph node metastases. The patient, who was suspected of having a pulmonary lesion on chest radiography performed at a local hospital, was referred to our hospital. Contrast-enhanced computed tomography (CT) of the chest showed a small-sized opacity in the left upper lung and multiple mediastinal nodules. The largest mediastinal nodule, depicted at a pretracheal region, was 22 mm in size. Thallium-201 single photon emission computed tomography (SPECT) showed increased uptake in these lesions, which exhibited no remarkable washout of the tracer, supportive of the diagnosis of lung cancer with mediastinal lymph node metastasis. However, bronchoscopic and mediastinoscopic biopsy revealed no malignant cells or reactive lymph nodes, respectively. Therefore, no surgical procedure was performed after the biopsy. The patient has done well without evidence of malignancy for 21 months. Radiologists should be careful in the differential diagnosis of benign and malignant lesions even with combined imaging modalities.     

胸部脂肪瘤的影像学诊断(附14例报告)

目的探讨胸部脂肪瘤的影像学表现及检查方法优选. 资料与方法搜集胸部脂肪瘤14例资料,包括肺脂肪瘤2例,胸壁脂肪瘤4例,纵隔脂肪瘤3例,胸腺脂肪瘤3例,横膈脂肪瘤1例,右心房脂肪瘤1例,全部病例均有胸部正侧位片,12例进行了CT检查,1例进行了MRI检查,对全部患者的影像学表现进行分析. 结果胸部正侧位片病灶发现率78.6%,漏诊原因与肿瘤密度过低,肿瘤沿胸壁深部肌间隙浸润生长或肿瘤位于平片上较隐蔽的部位有关.CT检查不仅可进行精确的定位诊断和分类诊断,而且能作出定性诊断,但应常规摄脂肪窗片.MRI对这类肿瘤最敏感,它对病变的发现、定位、分类诊断及定性诊断有决定性意义. 结论胸部正侧位片是胸部脂肪瘤的首选检查方法,但病变的分类诊断与定性诊断需依赖胸部CT与MRI,其中MRI是该类疾病的最佳检查方法.     

MR diffusion imaging and ADC measurement in solid and cystic mediastinal masses for differentiating benign from malignant lesions

Purpose

The purpose of this study is to evaluate the role of MR diffusion imaging (DWI) and apparent diffusion coefficient (ADC) measurement of solid and cystic mediastinal masses to differentiate benign from malignant lesions.