Cross-sectional imaging with CT and/or MRI of pediatric chest tumors

The purpose of this study was to provide an overview of the spectrum of pediatric chest masses, to present the results of cross-sectional imaging with CT and/or MRI, and to define diagnostic criteria to limit differential diagnosis. Seventy-eight children with thoracic mass lesions were retrospectively evaluated using CT (72 patients) and/or MR imaging (12 patients). All masses were evaluated for tissue characteristics (attenuation values or signal intensity, enhancement, and calcification) and were differentiated according to age, gender, location, and etiology. Twenty-eight of 38 (74 %) mediastinal masses were malignant (neuroblastoma, malignant lymphoma). Thirty of 38 (79 %) pulmonary masses were metastatic in origin, all with an already known primary tumor (osteosarcoma, Wilms tumor). With one exception, all remaining pulmonary lesions were benign. Seventeen of 21 (81 %) chest wall lesions were malignant (Ewing sarcoma, primitive neuroectodermal tumor). The majority of mediastinal and chest wall tumors in children is malignant. Lung lesions are usually benign, unless a known extrapulmonary tumor suggests pulmonary metastases. Cross-sectional imaging with CT and/or MRI allows narrowing of the differential diagnosis of pediatric chest masses substantially by defining the origin and tissue characteristics. Magnetic resonance imaging is preferred for posterior mediastinal lesions, whereas CT should be used for pulmonary lesions. For the residual locations both modalities are complementary. Received 7 March 1997; Revision received 9 September 1997; Accepted 14 November 1997     

Dynamic contrast-enhanced breath-hold MR imaging of thoracic malignancy using cardiac compensation

The purpose of this paper was to evaluate the use of dynamic gadopentetate dimeglumine-enhanced, breath-hold spoiled gradient-recalled (SPGR) MR imaging with cardiac compensation (CMON) compared to spin-echo MR imaging in patients with thoracic malignancy. We retrospectively reviewed MR images from 29 patients with thoracic tumors. MR imaging included axial electrocardiogram (ECG)-gated T1-weighted, fast spin echo (FSE) T2-weighted, and contrast-enhanced breath-hold fast multiplanar SPGR imaging with CMON, which selects the phase-encoding gradient based on the phase within the cardiac cycle. Images were reviewed for lung masses, mediastinal or hilar tumor, disease of the pleura, chest wall, and bones, and vascular compression or occlusion. Contrast-enhanced fast multiplanar SPGR imaging with CMON produces images of the chest that are free of respiratory artifact and have diminished vascular pulsation artifact. ECG-gated T1-weighted images were preferred for depicting mediastinal and hilar tumor. The gadopentetate dimeglumine-enhanced fast multiplanar SPGR images were useful for depicting chest wall tumor, vascular compression or thrombosis, osseous metastases, and in distinguishing a central tumor mass from peripheral lung consolidation. Pleural tumor was depicted best on the FSE T2-weighted images and the contrast-enhanced SPGR images. As an adjunct to spin echo T1-weighted and T2-weighted imaging, contrast-enhanced fast multiplanar SPGR imaging with CMON is useful in the evaluation of thoracic malignancy.     

Tumor invasion of the chest wall and mediastinum in lung cancer: evaluation with pneumothorax CT

For preoperative evaluation of chest wall and mediastinal invasion by lung cancer, computed tomography (CT), combined with artificial pneumothorax (pneumothorax CT), was performed in 43 patients with lung cancer in whom conventional CT scans showed that the mass was contiguous to the chest wall (n = 30) and/or mediastinum (n = 25) but without evidence of definite tumor invasion. Invasion was diagnosed on the basis of whether an air space existed between the mass and the adjacent structures. In three patients pneumothorax was not produced. After the procedure, four patients developed symptomatic pneumothorax, and one, subcutaneous emphysema. Comparison of diagnoses based on findings at pneumothorax CT, surgery, and pathologic examination showed that pneumothorax CT is 100% accurate for chest wall invasion and 76% accurate for mediastinal invasion. The authors conclude that this procedure is helpful in accurate evaluation of the T criterion in lung cancer, especially for patients in whom findings at conventional CT suggest tumor invasion of the chest wall and mediastinum.     

纵隔肿瘤定性诊断中值得重视的几种X线征象

通过对２１８例经病理学证实的纵隔肿瘤影像学资料（全部有胸部正、侧位片，８９例加作ＣＴ扫描，７例加作ＭＲＩ检查）的分析，讨论了５种对纵隔肿瘤平片定性诊断有价值的Ｘ线征象。立舌征提示胸腺瘤；倒置三角形征提示胸内甲状腺；肺尖圆球征提示后纵隔神经源肿瘤；攀藤征见于前纵隔者提示胸腺瘤，见于中纵隔者提示脉管性肿瘤；蛋壳样钙化征见于前纵隔者提示胸腺瘤，见于纵隔中上区者提示胸内甲状腺。     

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.     

Lung cancer staging: the role of computed tomography and magnetic resonance imaging

Because complete resection remains the only reliable method of cure of lung cancer, one important aim of preoperative staging is to select patients with localised disease who may benefit from surgery, while avoiding unnecessary thoracotomies in patients with unresectable neoplasm. Computed tomography (CT) of the chest is a valuable method for staging local and regional spread of lung neoplasms, although limitations in its accuracy are well-known. While gross invasion of the mediastinum and major structures as well as the presence of metastatic disease can be easily demonstrated with CT, differentiation between tumour contiguity and subtle invasion of mediastinum or chest wall often remains a problem. Although magnetic resonance imagaing (MRI) may have the same limitations as CT, in specific situations it may b superior in diagnosing minimal chest wall or mediastinal invasion. Moreover, MRI is useful in the assessment of patients with superior sulcus tumours as well as in patients with contraindication to intravenous administration of ionic contrast material. Since nodal size is the only useful criterion for evaluating lymph node metastases, CT and MRI show similar, poor accuracies in lymph node staging reesulting from both low sensitivity (normal-sized nodes may contain microscopic metastases) and low specificity (enlarged lymph nodes may be reactive). For this reason, if enlarged lymph nodes are detected, further evaluation is recommended before excluding the patient from a potentially curative resection. Advantages and limitations of CT and MRI in the preoperative staging of non-small-cell carcinoma are reviewed in this article. The imaging of small-cell carcinoma is not included because most patients with this cell type do not benefit from surgical resection. Similarly we do not discuss imaging of distant metastases.     

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.     

Imaging of penetrating chest trauma

This article discusses the role of imaging in evaluating patients who are admitted with penetrating injuries to the chest. Emphasis is placed on the role of multidetector row CT, which has been introduced in the past 5 years into the arena of care for trauma victims. It is important to take full advantage of this new CT technology with its capability to produce high-resolution multiplanar and volumetric images to diagnose penetrating chest injuries. This article emphasizes detection of active bleeding and assessment of the mediastinum for penetrating injury.     

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.     

Multislice computed tomography in staging lung cancer: the role of multiplanar image reconstruction

OBJECTIVE: The role of multiplanar image reconstruction (MPR) in staging lung cancer was investigated using multislice helical computed tomography (CT), which allows high-quality volumetric imaging. METHODS: Forty-one consecutive patients with lung cancer (mean age = 71 years) underwent multislice CT of the thorax. The scans were acquired using contiguous 4-mm x 2.5-mm slices from the lung apex to the diaphragm in a single breath hold after injection of 100 mL intravenous contrast media. Contiguous axial, coronal, and sagittal images (5-mm slice thickness) were reconstructed in the lung and mediastinal windows. The axial images with and without multiplanar reformatted images were reviewed on a workstation on 2 separate occasions (a minimum of 6 weeks apart) by 2 experienced chest radiologists. The films were assessed for features relating to the primary lesion (size; location; and invasion of the chest wall, mediastinum, diaphragm, and/or fissures) and secondary features (mediastinal lymphadenopathy and lung metastases). The diagnostic confidence of each feature was expressed on a 4-point scale. RESULTS: A significant increase in confidence was seen on the part of both observers when diagnosing features relating to the primary lesion. The mean confidence score increased from 1.68 to 2.08 (P = 0.038) for observer A and from 1.50 to 1.80 (P = 0.020) for observer B. Confidence in assessing invasion of fissures was increased from 1.70 to 2.30 (P = 0.022) for observer A and from 1.67 to 2.27 (P = 0.006) for observer B. Improvement in interobserver agreement (kappa-value from 0.61 to 0.75) was observed with multiplanar reconstruction (MPR) in the assessment of tumor location. No statistical difference was demonstrated in the diagnosis of mediastinal lymphadenopathy or lung secondaries. CONCLUSION: Multiplanar imaging of the thorax is a useful supplementary tool in the staging of lung cancer, particularly in delineating the relation of the primary lesion to fissures and the diaphragm.     

Evaluation of the role of chest computed tomography in the management of trauma patients

The role of chest computed tomography (CT) in the management of trauma patients is evolving. The present study reviews the chest radiographic and chest CT findings in a group of trauma patients to determine the clinical impact of findings noted exclusively on chest CT.Fifty-five trauma patients examined with chest radiography and chest CT and whose clinical charts were available for review were retrospectively identified. There were 46 men and 9 women, with a mean age of 39 years. The presence (and size) of pneumothorax, hemothorax, pulmonary contusion, and fractures was tabulated for the chest radiographs and CT scans. The presence of mediastinal widening on chest radiographs and all mediastinal findings on CT were noted. The results of aortography, when applicable, were correlated. The clinical charts were reviewed to assess the impact of CT findings on patient management.Pneumothorax (P<0.05), hemothorax (P<0.05), pulmonary contusions, and fractures were noted more frequently on chest CT than on chest radiography. However, clinical management was affected in only three (5%) of these patients. Chest CT findings related to the mediastinum affected patient management in 13 (24%) patients. CT obviated the need for aortography in 7 of 10 patients with mediastinal widening on chest radiographs. Six other patients had aortography, four for mediastinal hematoma with a normal-appearing aorta on contrast medium-enhanced CT, and two for mediastinal hematoma and aortic injury on CT.Despite detection of significantly more pneumothoraces and hemothoraces on chest CT, clinical management was affected in only a small minority (5%) of cases. CT did prove useful in evaluating the mediastinum, obviating the need for aortography in 7 of 10 patients with a widened mediastinum on chest radiography and accurately diagnosing the presence and site of aortic injury in the two patients with that diagnosis.     

Imaging of chest wall infections

A wide variety of infections can affect the chest wall including pyogenic, tuberculous, fungal, and some other unusual infections. These potentially life-threatening disorders are frequent especially among immunocompromised patients but often misdiagnosed by physical examination and radiographs. The purpose of this article is to describe the clinical and imaging features of these different chest wall infections according to the different imaging modalities with emphasis on ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI). The outcome of chest wall infection depends on early diagnosis, severity of the immunosuppression, offending organism, and extent of infection. Because clinical findings and laboratory tests may be not contributive in immunocompromised patients, imaging plays an important role in the early detection and precise assessment of the disease. US, CT, and MRI are all useful: bone destruction is more accurately detected with CT whereas soft tissue involvement are better visualized with US and MRI. CT and US are also used to guide percutaneous biopsy and drainage procedures. MR images are helpful in pre-operative planning of extensive chest wall infections.     

Askin瘤的影像诊断

目的:分析8例Askin瘤的影像征象。材料和方法:回顾性分析8例Askin瘤的胸部平片、B超和CT资料。年龄13~62岁,平均29.8岁。全组均拍摄正侧位胸片和CT扫描,6例胸壁肿瘤行B超检查。全组均经病理组织学和免疫组织化学检查证实。结果:6例原发于胸壁软组织,肿瘤较小(平均大小3cm),术后半数近期复发,复发灶平均大小为5.5cm。2例原发于纵隔,肿瘤平均大小为7cm。瘤实质主要为软组织,散在液化、坏死或出血。CT增强后扫描呈不规则强化。5例受累胸膜表现为不规则状、结节状增厚。结论:Askin瘤典型影像表现为胸壁、胸膜和纵隔病灶相互融合成巨大肿块。因此,面对青少年患者的胸部软组织肿瘤,鉴别诊断时应考虑到Askin肿瘤。     

Imaging of chest wall disorders.

Pathologic processes that may involve the chest wall include congenital and developmental anomalies, inflammatory and infectious diseases, and soft-tissue and bone tumors. Many of these processes have characteristic radiologic appearances that allow definitive diagnosis. Sternal deformities can be visualized at radiography and their severity quantified with computed tomography (CT). In cervical rib, CT with multiplanar reconstruction may demonstrate relevant anatomic detail and the relationship between bone deformity and arterial compression. In Poland syndrome, radiography reveals an area of hyperlucency on the affected side, whereas CT demonstrates the absence of the greater pectoral muscle and clearly depicts associated musculoskeletal anomalies. Tuberculosis typically manifests at radiography and CT as osseous and cartilaginous destruction and soft-tissue masses with calcification and rim enhancement. Aspergillosis involving the chest wall manifests as pulmonary consolidations and permeative osteolytic changes of the rib and spine at CT and as an area of increased signal intensity at T2-weighted magnetic resonance (MR) imaging. Neurogenic tumors and hemangiomas also typically have high signal intensity at T2-weighted MR imaging. Apparent mass extension or unequivocal bone destruction seen at CT or MR imaging may indicate chest wall involvement by lymphoma. Radiologically, soft-tissue sarcomas typically appear as areas of soft-tissue density or attenuation, often associated with necrotic areas of low density or attenuation. At radiography, plasmacytoma typically manifests as well-defined, "punched-out" lytic lesions with associated extrapleural soft-tissue masses. Chondrosarcoma frequently appears as a large, lobulated excrescent mass arising from a rib with scattered flocculent calcifications characteristic of its cartilaginous mix. Familiarity with these radiologic features facilitates accurate diagnosis and optimal patient treatment.     

原发纵隔囊肿影像学表现

目的探讨原发纵隔囊肿影像表现特征,提高影像诊断的准确率。方法回顾性分析经手术病理证实且资料完整的42例原发纵隔囊肿的影像学表现。所有病例均摄胸部后前位与侧位片,胸部CT平扫29例,其中15例行增强扫描,胸部MRI平扫6例。观察病变的部位、大小、形态、密度(信号)、边缘、壁及其厚度、邻近结构。每一病种均分为影像征象典型与不典型2类。结果病变位于前纵隔28例,中、后纵隔各7例。上纵隔9例,中纵隔24例,下纵隔9例。支气管囊肿9例,囊性淋巴管瘤4例,胸腺囊肿11例,心包囊肿5例,成熟性囊性畸胎瘤13例。影像征象典型38例,不典型4例。结论90%的纵隔囊肿,根据CT、MRI显示的病变部位与内部密度、信号特征,可做出正确的影像诊断;不典型者确诊仍依靠手术病理。     

纵隔囊性病变的CT与MRI诊断

目的：探讨纵隔囊性病变的CT、MRI诊断及鉴别诊断。方法：回顾性总结30例经手术、病理确诊的纵隔囊性病变的CT及MRI表现，包括胸腺囊肿7例，囊性畸胎瘤8例，气管、支气管囊肿9例，食管囊肿4例，囊性淋巴管瘤2例。结果：不同纵隔囊性病变均有其较特定的发病部位。7例胸腺囊肿中6例位于前上纵隔的胸腺区，1例位于前纵隔中下部；8例囊性畸胎瘤主要位于前纵隔中部、大血管起始处；9例气管、支气管囊肿位于中上纵隔，气管、支气管右旁区；4例食管囊肿，其中3例位于后纵隔，1例位于中纵隔；2例囊性淋巴管瘤，其中1例为颈纵隔型，1例为颈一腋纵隔型。结论：纵隔囊性病变虽无明显特征性影像学表现，仔细观察CT与MRI征象特点，结合发病部位，对提高本病的诊断具有重要意义。     

Tumors of the pediatric chest

A wide spectrum of malignant and benign diseases can present as tumors involving the chest in children. The imaging evaluation of these children is initially directed by clinical presentation and usually begins with a chest radiograph. Further imaging with CT, MRI, or rarely ultrasonography may be performed to better detect, localize, or characterize the lesion(s). The differential diagnosis of these tumors is guided not only by tumor location and characterization, but also by patient age and clinical presentation. Familiarity with the clinical and radiographic aspects of these diseases will help the radiologist to continue to play a crucial role in the diagnosis and management of these children.     

纵隔型肺癌的CT及MR表现分析

目的 探讨纵隔型肺癌CT及MRI诊断能力.方法 回顾分析15例经纤支镜、穿刺活检及手术病理证实为纵隔型肺癌的CT及MRI影像资料,15例全部行CT平扫,其中11例增强扫描,3例行MR平扫与增强扫描.分析CT及MRI图像上肿块的位置、大小、形态、边缘及其与纵隔和肺的关系.结果 15例纵隔型肺癌为单发肿块,5例小细胞型肺癌,8例鳞癌、腺癌及腺鳞癌各1例.肿块均位于纵隔胸膜下,与纵隔呈宽基底相贴,大多呈类圆形或椭圆形.边缘分叶12例,毛刺9例.肿块位于上纵隔8例,中纵隔5例,下纵隔2例.其中前中纵隔区12例,后纵隔3例.肿块与肿大淋巴结融合7例.癌肿邻近相应支气管变窄或闭塞9例.4例有胸廓骨转移性骨质破坏.结论 纵隔型肺癌易误诊,仔细分析CT及MRI表现,结合临床可作出较准确的诊断.     

Primary malignant fibrous histiocytoma of the chest wall: CT and MR appearance

PURPOSE: The purpose of this work is to describe the CT and MR appearance of primary malignant fibrous histiocytoma (MFH) of the chest wall. METHOD: Eleven men and eight women (45-76 years old) with primary MFH of the chest wall who underwent both CT and MRI were enrolled, and the imaging interpretation was retrospectively compared to the pathologic specimen. RESULTS: All tumors were inhomogeneous in appearance on CT scans. All tumors showed high signal intensity on T2-weighted images. On T1-weighted MR images, tumors displayed inhomogeneous isosignal intensity in 15 cases (79%) and low signal intensity in 5 (21%) compared with the surrounding muscle. Tumors exhibited inhomogeneous enhancement in all except three localized tumors on enhanced CT and MRI. Invasion of intercostal muscle was noted on MR images in 18 patients (95%) and on CT in 11 patients (58%). CONCLUSION: There might be various radiologic appearances of MFH. However, CT and MRI are able to demonstrate the exact localization and disease extent of MFH arising in the chest wall.     

Diagnosis of chest wall invasion by lung cancer: useful criteria for exclusion of the possibility of chest wall invasion with MR imaging

PURPOSE: To compare the accuracy of thin-section CT, conventional static MR imaging (conventional MRI), and breathing dynamic echo planar magnetic resonance imaging (BDEPI) in evaluating lung cancer invasion to the chest wall. MATERIALS AND METHODS: Thin-section CT, conventional MRI, and BDEPI were performed preoperatively in 20 patients suspected of having primary lung cancers adjacent to the chest wall on conventional CT. The results of imaging findings were compared with those of surgical and histopathological findings. RESULTS: All patients were confirmed to have no chest wall invasion after surgery. By thin-section CT, 10 of 20 patients were correctly diagnosed as having no chest wall invasion (50% specificity). Two of the 20 patients were incorrectly diagnosed as having chest wall invasion by conventional MRI and BDEPI (90% specificity). CONCLUSION: When chest wall invasion is suspected on CT scans, static and breathing dynamic MRI are recommended to avoid false positive interpretations.