Subcarinal lymph node enlargement: radiographic findings and CT correlation

Detection of subcarinal lymph node enlargement on the posteroanterior chest radiograph was assessed in 90 patients who also had computed tomography (CT). Sixty of the 90 patients had normal-sized and 30 had enlarged (greater than 15 mm diameter) subcarinal lymph nodes on CT. An abnormality in the contour of the azygoesophageal recess interface was present on plain radiographs in only 23% of patients with lymphadenopathy; increased subcarinal opacity was present in 40%. The external surface of the medial wall of the right main-stem bronchus and bronchus intermedius was visible in 87% of patients with normal-sized lymph nodes but in only 27% of patients with lymphadenopathy. CT showed that the medial wall of the right main-stem and intermediate bronchi normally is delineated laterally by air within the bronchus and medially by lung or subcarinal fat. Nonvisualization may be due to replacement of lung or fat by enlarged nodes or tumor and may be helpful in assessing patients with suspected subcarinal adenopathy.     

Evaluation of the "N" factor in nonsmall cell lung cancer. Correlation between computerized tomography and pathologic anatomy

PURPOSE: To evaluate the role of CT in identifying other morphological signs of metastatic lymph node involvement from non small cell bronchogenic carcinoma. This is done to improve N staging, a critical step in this disease. In fact, since diameter is the only criterion used to distinguish normal form abnormal lymph nodes, medistinal CT only has 80% diagnostic accuracy. MATERIAL AND METHODS: 137 patients with known or suspected lung cancer were examined with Helical CT during early and late arterial phases (2 min delay, 3 mm thickness, 5 mm interslice gap) to depict node characteristics. Mediastinal lymph nodes, located according to the American Thoracic Society mapping, were considered normal when they were not visible or, if visible, less than 1 cm in diameter and of homogeneous density; lymph nodes over 1 cm in diameter and homogeneous density were considered reactive. A lymph node was considered metastatic when, independent of size, the following signs were found: central hypodensity; hyperdense thin/thick rim, with nodules within; hyperdense strands or diffuse hyperdensity in perinodal adipose tissue. The tumor site was also considered. RESULTS: Seventy patients were excluded because they were inoperable. Sixty-five of the remaining 67 patients were operated on, 1 underwent mediastinoscopy and another one mediastinoscopy followed by surgery. Based on the above CT signs, 46 patients were staged as N0, 61 as N1 and 15 as N2. In 44/46 N0 patients there was agreement between anatomical and pathologic findings; 3 of the 44 patients had lymph nodes over 1 cm in diameter and with homogeneous density. Micrometastases to mediastinal lymph nodes (N2) were found at histology in 2/46 patients (CT false negatives). In the 6 N1 and the 15 N2 patients there was complete agreement between anatomical and pathologic findings; in particular, 9 N2 patients had lymph nodes less than 1 cm in diameter with signs of metastasis and 4 had lymph nodes over 1 cm in diameter with signs of metastasis and 2 had lymph nodes either over or less than 1 cm. In all N2 patients the tumor histotype and the mediastinal location were also considered relative to the lesion site. DISCUSSION: A closer correlation was found with node morphology and density than with size. Indeed, CT sensitivity, specificity and diagnostic accuracy were 97, 100 and 97%, respectively, for the former versus 52, 93 and 77% for the latter. Adenocarcinoma was the predominant histotype (70.5%) in N2 patients. Metastases to node region 4 were predominant in right upper lobe carcinomas while node region 5 was predominant in left upper lobe lesions. CONCLUSIONS: Other criteria can be associated with size to improve CT diagnostic accuracy in N staging. Technique optimization plays a major role particularly in the late, thin slice, examination phase.     

T1N0M0 bronchogenic carcinoma: assessment by CT

We reviewed medical records and conventional chest radiographs that showed a solitary T1N0M0 nodule in 23 patients who had non-oat-cell bronchogenic carcinoma. No patient had evidence of metastases, either on the chest radiograph or clinically. All patients underwent computed tomography (CT) examination of the thorax, including the adrenal glands. Only one patient (4%) had mediastinal lymph nodes greater than 1 cm in diameter accessible to mediastinotomy; anterior mediastinotomy confirmed metastatic spread in this patient, which precluded curative resection. Three patients each had a mildly enlarged (2 cm or less) adrenal gland; however, follow-up study suggested that metastasis was not the cause of adrenal enlargement in these patients. This study reinforces concern over whether CT is warranted in the preoperative assessment of T1N0M0 bronchogenic carcinoma.     

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.     

胸段食管癌颈胸腹三野淋巴结转移的CT表现与分布特征

目的通过对胸段食管癌颈胸腹三野淋巴结转移CT影像分析,探讨其分布特征。方法对110例经病理及影像随诊证实胸段食管癌转移性淋巴结的位置、大小、数目、形态及强化特征进行分析。淋巴结根据美国胸科协会（ATS）的纵隔淋巴结分组标准及颈腹部淋巴结分组标准分为15组,设定淋巴结直径大于1.0 cm为转移淋巴结。结果 110例胸段食管癌中,共观察到231枚转移性淋巴结。胸段食管癌淋巴结转移以右下气管旁组、主肺动脉窗组、隆突下组最多,其次为右上气管旁组、右锁骨上组、胃左动脉旁组及腹腔干旁组。中上段食管癌注意观察右上气管旁组及右锁骨上组,中下段食管癌注意观察胃左动脉旁组及腹腔干旁组。结论螺旋CT可以准确显示颈胸腹三野淋巴结转移的分布特征,为临床分期及选择合理化的治疗方案提供重要依据。     

Aortopulmonary window lesions: detection with chest radiography

A retrospective morphologic study of 80 cases was undertaken to determine factors affecting detectability of computed tomographically (CT) proved aortopulmonary (AP) window lesions on conventional posteroanterior (PA) and lateral chest radiographs. Criteria used for determining abnormality were: solitary lymph node enlargement over 1.5 cm or three or more 1-cm nodes and obvious large masses or vascular anomalies. CT scans and corresponding PA and lateral radiographs were analyzed for lesion detectability, size, and location. In 49% of cases there was no detectable lesion in the AP window on radiographs; a definite AP window lesion was seen in 41%, and 10% were equivocal. Major contributing factors to low detectability of AP window lesions on radiographs include size and, more important, location of the lesion. An additional 45 cases of CT-proved normal AP windows were retrospectively reviewed to determine the false-positive rate of PA and lateral radiographs in detection of AP window lesions: 43 (96%) were classified as negative, the remaining two (4%) as equivocal. Although the AP window is a small space, it is the site of many pathologic conditions; the study results indicate that CT may be an essential procedure for its evaluation.     

Mediastinal evaluation in lung cancer

Findings of mediastinal imaging were compared with pathologic findings following thoracotomy and full nodal sampling in 50 patients with bronchogenic carcinoma. All patients underwent full nodal sampling and chest radiography, conventional tomography, CT, and Ga-67 radionuclide scanning. The highest sensitivity for mediastinal metastases noted was 54%, considering nodes greater than or equal to 1.0 cm abnormal at CT. The small size of some involved nodes precluded sensitivity from reaching 100%. Using differing size criteria for nodal abnormality at CT (greater than or equal to 1.0 cm, greater than or equal to 1.5 cm, greater than or equal to 2.0 cm abnormal) sensitivity decreased as specificity increased. The highest specificity noted was 97% with CT, considering nodes greater than or equal to 2.0 cm abnormal. Ga-67 scanning did not offer additional information when compared with that of other studies. The predictive value of considering mediastinal lymph nodes greater than or equal to 1.0 cm abnormal at CT was 35%. Reasons for this include reactive nodes proximal to obstructions and prior granulomatous disease. In 13 peripheral T1N0 cancers (determined by chest radiography) no additional information was gained with any other imaging technique. The utility of CT in peripheral T2 cancers and central cancers is not clear.     

Non-seminomatous testicular tumors: Effect of lesion side on CT detection of lymph node metastasis

Abdominal CT examinations of 40 patients with non-seminomatous testicular tumors were reviewed with previous knowledge of the side of the testicular primary. Metastatic nodes, between 1.5 cm and 2.0 cm in diameter were overlooked more frequently in patients with right than in those with left testicular primaries, because mildly enlarged aorto-caval or para-caval nodes (which are the most frequent site of metastasis from a right testicular lesion) were more difficult to detect than enlarged left para-aortic lymph nodes. Efforts to delineate the aorto-caval region on CT examinations of patients with right-sided lesions must be increased in order to reduce a surprisingly high false negative rate.     

Contribution of computer tomography to the diagnosis of bronchial carcinoids

The CT findings in 10 patients with carcinoid tumors of the lung (highly differentiated in 8 cases, undifferentiated in 2 cases) are reported. The tumors were located in the hilar region (n = 4), in the perihilar region (n = 3) and in the periphery of the lung (n = 3). Dystelectasis and atelectasis of the lung with poststenotic inflammation were found in 4 patients. Infiltrating tumor growth with lymph node metastases were detected only once; this tumor was not able to be differentiated from other malignant space occupying lesions. There were no reliable CT criteria for bronchial carcinoids. Compared to conventional radiography the CT examination has the following advantages: better demonstration of size and location of the tumor, and the exclusion of infiltrating tumor growth, enlarged lymph nodes and calcified lung nodules.     

Location,size, and distribution of mediastinal lymph node enlargement in chronic congestive heart failure

PURPOSE: The purpose of this study is to identify the prevalence, location, and size of enlarged mediastinal lymph nodes in patients with chronic congestive heart failure and to correlate the presence of lymph node enlargement with cardiac ejection fraction. METHODS: Sixty-six consecutive, retrospectively identified patients underwent computer tomography (CT) imaging of the thorax as part of a routine work-up prior to cardiac transplantation from 1993 to 1996. CT images of 44 of these patients were independently examined by 3 radiologists for evidence of pulmonary edema, pleural effusions, and the presence, size, and location of lymph nodes >1 cm in short axis. Multigated acquisition (MUGA) scans were available for cardiac ejection fraction assessment in 38 of the 44 patients. RESULTS: Twenty-nine (66%) patients had at least 1 mediastinal lymph node >1 cm. The mean ejection fraction was significantly less for patients with lymph node enlargement when compared with patients without lymph node enlargement (20% versus 35%; P < 0.01). Adenopathy was observed in 81% of patients with a calculated ejection fraction of <35%. No patient with an ejection fraction of >35% had lymph node enlargement. There was no correlation between pulmonary edema and the frequency of lymph node appearance. Sixty-three percent of the enlarged nodes were pretracheal, with a mean short axis diameter for all the enlarged nodes of 1.3 cm. CONCLUSIONS: Enlarged mediastinal lymph nodes were observed in 81% of patients with a calculated ejection fraction of <35%, most commonly in the pretracheal group. The presence of the lymph nodes did not correlate with CT evidence of pulmonary edema.     

Magnetic resonance imaging, chest radiography, computed tomography and ultrasonography in malignant lymphoma

Magnetic resonance imaging (MRI) was compared with chest radiography, computed tomography (CT) and ultrasonography (US) for demonstration of spleen and liver engagement and enlarged lymph nodes in patients with malignant lymphoma. The investigation comprised 24 patients with Hodgkin's disease (HD) and 39 with non-Hodgkin lymphoma (NHL). MRI demonstrated enlarged lymph nodes, distinctly separated from vessels, fat, muscle, liver and occasionally also pancreas without any contrast medium. The distinction between lymph nodes and spleen was, however, poor in the images. In the mediastinum, MRI was superior to chest radiography and had an accuracy similar to that of CT. In the abdomen and the pelvis MRI had slight advantages over CT in detection of enlarged lymph nodes. Compared with US the MRI results were similar in the abdomen and somewhat better in the pelvis. MRI and US were better than CT in revealing HD infiltrates in the spleen. Infiltration of NHL in the spleen was slightly better disclosed at US than at CT and MRI; most of the NHL infiltration, confirmed at histopathology, could, however, not be revealed with any of the modalities, except when the size of the spleen was considered. Regions in the spleen, displayed with low image intensity in the T2 weighted image, were most likely due to increased amount of fibrotic tissue in the lymphomatous lesions. Good demonstration of lymph nodes and lymphomatous lesions in the spleen with MRI required two sequences; one with short TR and TE (T1 weighted image) and one with long TR and TE (T2 weighted image).     

CT evaluation of cardiophrenic angle lymph nodes in patients with malignant lymphoma

Two hundred seventy-four computed tomographic (CT) scans of the thorax were obtained in 209 patients with malignant lymphoma (153 Hodgkin disease and 56 non-Hodgkin lymphoma). Fourteen patients (6.6%) were shown to have adenopathy involving the cardiophrenic angle lymph nodes on CT. Of these, only three were considered positive on the basis of chest radiography alone. The anatomy of these diaphragmatic lymph nodes and CT appearance of these nodes when pathologically enlarged are discussed.     

淋巴结反应性增生的CT诊断

目的分析淋巴结反应性增生的CT表现及CT的诊断价值。方法回顾性分析13例经手术及病理证实的淋巴结反应性增生的CT表现。结果13例淋巴结反应性增生中,单独侵犯颈外侧淋巴结7例,同时侵犯颈外侧区及面淋巴结、颏下淋巴结各2例,1例侵犯腋窝及腹股沟淋巴结,1例为颈、腋、纵隔、腹膜后区和腹股沟淋巴结同时肿大。肿大淋巴结短径最小0.6 cm,最大2.6 cm,平均1.6 cm。肿大淋巴结孤立存在12例,仅1例有融合。1例因相互融合而密度不均,12例密度均匀并有明显强化,增强后CT值增加19.1~113.2 HU,平均59.1 HU。结论淋巴结反应性增生的CT表现有一定的特征性,CT检查对该病的定性诊断与鉴别诊断具有重要价值。     

Enlarged mediastinal lymph nodes in the fibrosing alveolitis of systemic sclerosis.

The aim of this study was to determine the prevalence of enlarged mediastinal lymph nodes in systemic sclerosis (SSc) and relate this to the extent of pulmonary disease and disease activity as judged by high resolution computed tomography (HRCT). The HRCT scans of 78 patients with SSc were reviewed. The extent of lung disease and HRCT pattern were analysed and CT scans examined on soft tissue window settings for evidence of mediastinal lymph node enlargement. Sixty six (85%) patients had evidence of lung involvement on CT. Enlarged mediastinal lymph nodes were present in 21 (32%) patients with lung involvement but in only 1 (8%) patient without. The prevalence of enlarged mediastinal nodes increased with more extensive lung involvement on CT (p < 0.025), but correlated poorly with the type of CT appearance and concurrent erythrocyte sedimentation rate. Mediastinal lymph node enlargement occurs frequently in patients with SSc, particularly if lung involvement is extensive.     

Paratracheal lymphadenopathy: radiographic findings and correlation with CT

Possible signs of paratracheal lymphadenopathy on the posteroanterior (PA) chest radiograph were assessed in 98 patients and correlated with computed tomography (CT). The nodes were normal in size in 62 patients and enlarged (greater than 15 mm) in 36. Among the latter group, widening of the right paratracheal stripe was seen in 11 (31%) and enlargement of the azygos node in 15 (42%). While the lateral contour of the superior vena cava (SVC) was convex in 46 patients (47%), 81 (83%) had an increased density in the region of the SVC. When all four parameters were combined, lymphadenopathy could be detected on the PA view in 87 patients (89%). CT demonstrated that the enlarged nodes were anterolateral rather than directly lateral to the trachea and also immediately posterior to the SVC, explaining the findings on the PA radiograph.     

CT of interpectoral lymph nodes

The presence of lymph nodes between the pectoralis major and minor muscles (Rotter's nodes) has been noted in the anatomic and surgical literature. We analyzed the appearance of the interpectoral space and nodes on chest CT scans of 25 patients without known chest wall abnormalities or causes for lymphadenopathy. In some of these cases small structures were detected in the interpectoral fat that could be either vessels or nodes. In addition we studied chest CT scans in six patients with interpectoral adenopathy due to metastases from breast cancer. The nodes were oval soft-tissue densities ranging from 1.5 X 1 cm to 3.5 X 3 cm in diameter.     

Mediastinal lymph node involvement in non-small cell lung cancer: evaluation with 99mTc-tetrofosmin SPECT and comparison with CT.

In patients with non-small cell lung cancer (NSCLC), surgical resection offers the best chance of cure. The preoperative assessment of mediastinal lymph node involvement is crucial to selecting those patients for whom surgery is indicated. METHODS: To evaluate the possible clinical role of (99m)Tc-tetrofosmin scintigraphy in the presurgical detection of mediastinal node metastases from NSCLC, we performed a prospective comparative study with CT on 83 patients (48 men, 35 women; age range, 38-81 y) with primary NSCLC (36 adenocarcinomas, 39 epidermoid squamous cell carcinomas, and 8 large cell anaplastic carcinomas). They underwent chest SPECT 20 min after (99m)Tc-tetrofosmin injection (740 MBq intravenously). The metastatic involvement of mediastinal nodes was assessed by histologic examination after mediastinoscopy or thoracotomy. Both chest CT and (99m)Tc-tetrofosmin scintigraphy were performed within 2 wk before the surgical staging. RESULTS: Metastatic mediastinal lymph nodes were found in 35 patients. (99m)Tc-Tetrofosmin imaging in assessing the mediastinal involvement yielded a sensitivity of 85.7%, a specificity of 89.6%, and an accuracy of 88.0%; CT results were 68.6%, 75.0%, and 72.3%, respectively. SPECT accuracy was significantly higher than CT accuracy (P < 0.05). However, precise anatomic localization of (99m)Tc-tetrofosmin uptake in the mediastinum was not always present on SPECT images. (99m)Tc-Tetrofosmin SPECT precisely detected the presence or absence of lymph node metastases in 33 of the 36 patients with positive CT findings (enlarged mediastinal nodes with a short axis > or =1 cm), with an accuracy (91.7%) significantly higher (P < 0.05) than that of CT (66.7%). CONCLUSION: (99m)Tc-Tetrofosmin SPECT is a useful presurgical noninvasive method to assess mediastinal lymph node involvement in NSCLC. In particular, it could play a clinical role in reducing the number of invasive staging surgical procedures in selected patients, especially in those with enlarged lymph nodes at CT. Fusing SPECT with CT images could further improve the interpretation of the scintigraphic data.     

艾滋病合并非结核分枝杆菌肺病的胸部影像表现

目的 探讨艾滋病合并非结核性分枝杆菌肺病的胸部影像表现.方法 10例艾滋病合并非结核性分枝杆菌肺病患者均行胸部X线检查,其中7例行胸部HRCT检查.结果 10例患者X线胸片显示:9例有明显病变,1例只有轻微病变;6例为双肺受累,4例为单肺受累(其中右肺3例,左肺1例);其中5例为大面积实变并空洞形成(4例伴对侧肺野散发病灶).在病变形态上有斑片状渗出实变(6例)、大片状(叶、段分布)实变(5例)、空洞(5例)、小结节病灶(3例)、粟粒病灶(2例)、纤维索条(1例).7例患者HRCT显示:斑片状渗出实变(7例)、小结节病灶(6例)、大面积(肺叶、段)实变(5例)及随实变吸收消散而出现的空洞、支气管扩张(各5例),纵隔淋巴结肿大(4例),磨玻璃密度影(3例),粟粒病灶及树芽征(各2例),胸腔积液、心包积液、纤维索条(各1例).结论 大面积实变合并空洞、结节病灶、支气管扩张及纵隔和肺门淋巴结肿大是艾滋病合并非结核性分枝杆菌肺病的胸部影像特点.     

Magnetic resonance imaging of the lymph nodes: comparison with CT

This retrospective study of 144 patients was made to (a) assess the potential of magnetic resonance (MR) for demonstrating lymph nodes using spin-echo technique, (b) compare the MR results with those of CT, and (c) determine the optimal pulse-sequence interval (TR) and echo-delay time (TE) for imaging lymph nodes. The reported CT findings on normal lymph nodes were compared with MR findings in 60 patients who underwent MR imaging of the neck (20 patients), chest (20 patients), abdomen (10 patients), and pelvis (10 patients) for conditions other than lymph node disease. The results showed that CT is presently better than MR for imaging neck and abdominal lymph nodes less than 13 mm in diameter. The ability of MR to demonstrate normal-size (less than 10 mm) lymph nodes in the chest was comparable to that of CT. In addition, MR scans of 84 patients with proven abnormal lymph nodes (8 neck, 49 chest, and 27 abdomen and pelvis) were assessed: in 72 patients, these nodes had also been imaged by CT. MR and CT gave similar results with abnormal lymph nodes (greater than 13 or 15 mm), but MR displayed these nodes better because of its excellent soft-tissue contrast resolution. MR can clearly differentiate abnormal lymph nodes from normal fat, muscle, vessels, adult thymus, thyroid, and diaphragmatic crura, as well as from primary tumor and lymphoceles. Optimal demonstration of lymph nodes with MR required two sequences: one with a short TR and one with a long TR and long TE. Preliminary results indicate that MR holds great promise for the demonstration of lymph nodes in every part of the body.     

Cryptococcus infection in a patient with nasopharyngeal carcinoma: imaging findings mimicking pulmonary metastases

An asymptomatic pulmonary mass was found in a 42-year-old unmarried male with controlled nasopharyngeal carcinoma (NPC) during routine follow-up chest radiography 8 months following completion of radiotherapy. Chest CT demonstrated a 3x2 cm(2) left lower lobe (LLL) mass, with further small nodules in the same lobe. A presumptive diagnosis of lung metastases was made, and the patient underwent surgical resection with left lower lobectomy and mediastinal lymph node dissection. Pathologic examination of the masses in the LLL revealed granulomatous inflammation with cryptococcus infection. The dissected lymph nodes revealed anthracosis. The patient received 6 months of antifungal treatment with fluconazole. His NPC showed no evidence of local recurrence or distant metastases. Recognition that pulmonary cryptococcus infection can mimic metastases is important in reaching the correct diagnosis and therefore determining the correct treatment.