Intrapulmonary lymph nodes: CT and pathological features.

Intrapulmonary lymph nodes are not uncommon and may be seen frequently in high quality computed tomography (CT) images and chest radiographs. We report four patients, older than 55 years, who had a long history of heavy smoking. Four intrapulmonary lymph nodes were located in the subpleural region (within 3 mm of the visceral pleural surface) of the right or left lower lobes. The lymph nodes were ovoid or round, homogeneous, well-defined and ranged from 9 to 10 mm in diameter. In one case, coexistent small nodules in the same or in other lobes on initial CT studies increased slightly in size over the following 3 years. All nodules contained lymphoid follicles and anthrocotic pigment, and in one case adjacent small aggregates of lymphocytes along interlobular septa were seen. Intrapulmonary lymph nodes have non-specific CT and clinical features. Follow-up CT may be useful in patients with suspected intrapulmonary lymph nodes.     

Thin-section CT features of intrapulmonary lymph nodes

PURPOSE: The objective of this study was to evaluate CT findings of pathologically proven intrapulmonary lymph nodes (IPLNs) and discuss the utility of thin-section CT and contrast-enhanced CT. METHOD: CT findings of 18 nodules in 14 patients with pathologically proven IPLNs were reviewed. CT scanning of the whole lung was performed contiguously with slice thickness of 10 mm. In addition, a helical scan with slice thickness of 2 mm was performed in nine patients, focusing on the nodule. Contrast-enhanced helical CT was performed in four patients, and the utility of thin section CT and contrast-enhanced CT was investigated. RESULTS: One patient had three nodules, 2 patients had two nodules, and the remaining 11 patients had a solitary nodule. All nodules were located below the level of the carina and within 15 mm of the pleura. In one case, conventional CT revealed the nodule 20 mm away from the pleura; however, the nodule attached to the major fissure was clearly revealed on thin-section CT. The size of the nodules was < or =15 mm, and the shape was round (n = 8), oval (n = 9), or lobulated (n = 1) with sharp border. One nodule demonstrated a spiculated border due to a surrounding pulmonary fibrosis on conventional CT; however, thin-section CT showed precisely a sharp border. The lobulated shape of one case histopathologically reflected a hilus of lymph node. On contrast-enhanced helical CT, all four nodules were enhanced and the degree enhancement was 36-85 HU (median 66.6 HU). CONCLUSION: In current times, IPLNs are not uncommon lesions. We should consider IPLN in the differential diagnosis of solitary or multiple pulmonary nodules in the peripheral field and below the level of the carina. Thin-section CT showed precisely the border or relation between IPLNs and the surrounding structure. It was difficult to distinguish between IPLNs and malignant nodules from the degree of enhancement on contrast-enhanced CT. On thin-section and contrast-enhanced CT, the findings of IPLNs are not necessarily specific. Therefore, strict observation on CT is necessary; in certain cases that are increasing in size, video-assisted thoracic surgery should be considered because of their location.     

Minute pulmonary meningothelial-like nodules: thin-section CT appearance

Minute pulmonary meningothelial-like nodules are often incidentally discovered during pathologic evaluation of pulmonary parenchymal specimens. These lesions were once thought to represent pulmonary chemodectomas, but pathological studies have shown that they are not of neuroendocrine origin. Minute pulmonary meningothelial-like nodules are benign, perhaps reactive in nature, but are occasionally found in association with lung carcinoma. They may appear as randomly distributed well-defined micronodules on thin-section chest CT, and thus may simulate metastatic disease when associated with lung carcinoma.     

腮腺淋巴结结核病的CT表现

大涎腺的结核病很罕见,即使在结核病高发病区亦属少见.大涎腺结核病有70%发生在腮腺,27%发生在颌下腺,3%发生在舌下腺[1].腮腺结核病多数发生于腮腺淋巴结,少数发生在腮腺实质内.     

CT features of intrapulmonary lymph nodes confirmed by cytology

We retrospectively assessed the computed tomography features of intrapulmonary lymph nodes confirmed by cytology in 18 patients. The median size of the lymph nodes was 5.8 mm (range=3.3–8.5 mm). All were below the carina, and only one nodule, which was associated with an interlobar fissure, was over 20 mm from the chest wall. The nodules were oval, round, triangular, or trapezoidal; had sharply defined borders; were solid and homogenous; and were without calcification. Six nodules (33.3%) had a discrete thin tag extending to the pleura. Intrapulmonary lymph nodes can reliably be confirmed by fine needle aspiration with cytological diagnosis.     

Intrapulmonary lymph nodes: computed tomography findings with histopathologic correlations

We retrospectively assessed the computed tomography (CT) features of 31 intrapulmonary lymph nodes (IPLNs) with histopathologic correlations. CT scans revealed that the IPLNs are located in the subpleural region, frequently below the level of the carina, and angular in shape. Most of the IPLNs are solid in texture but occasionally present with a ground-glass appearance. For pleura-attached and pleura-separated IPLNs, one or more and 3 or more linear opacities extending from the nodules can be identified, respectively. Histologically, the IPLNs are located either at the junction of the pleura and lung lobules or at the junction of adjacent lung lobules.     

Appearances of mediastinal and pulmonary hilar lymph nodes on thin-section CT: comparison with 5 mm slice thickness CT

AIM: This study aimed to evaluate the efficacy of thin-section CT of the mediastinum in the assessment of thoracic lymph nodes in comparison with conventional CT. MATERIALS AND METHODS: A total of 193 CT examinations from 193 patients with suspected pulmonary disease were reconstructed into thin-section CT and conventional CT. The appearances of the lymph nodes were assessed and compared between thin-section CT and conventional CT. RESULTS: Intranodal fat was more often detected on thin-section CT than on conventional CT (P<.001). There were no statistically significant differences in the frequencies of inhomogeneous enhancement and bulging margin of the hilar lymph node. CONCLUSION: Thin-section CT can improve clinical N-staging of lung cancer due to classification of enlarged mediastinal lymph nodes as benign based on identification of intranodal fat.     

Metastases to pelvic lymph nodes from carcinoma in the pelvic cavity: diagnosis using thin-section CT

OBJECTIVE: To assess the accuracy of thin-section computed tomography (CT) in the diagnosis of pelvic lymph nodes affected by metastatic cancer. METHODS: Incremental CT was performed by obtaining 3 mm sections with 3 mm intervals in 34 patients who had carcinoma in the pelvis, pre-operatively and prospectively. CT diagnoses were made before surgery using the cine mode with a manual trackball. Lymph nodes with a maximum short axis diameter of greater than 5 mm were considered enlarged. RESULTS: The accuracy, sensitivity, specificity, positive and negative predictive values of CT diagnoses were 79.7%, 54.5%, 84.9%, 42.9% and 90.0% on a hemipelvis basis; and 79.4%, 85.7%, 77.8%, 50.0% and 95.5% on a patient basis, respectively. There was only one false-negative case on a patient basis analysis. CONCLUSION: Because of a fairly high negative predictive value, negative thin-section CT can be considered an alternative to surgical lymphadenectomy. This is clinically important as unnecessary staging operations and extended surgery are avoided.     

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.     

Asbestosis and idiopathic pulmonary fibrosis: comparison of thin-section CT features

PURPOSE: To identify differences, if any, in thin-section computed tomographic (CT) features between asbestosis and idiopathic pulmonary fibrosis (IPF) and to test the findings in a subset of histopathologically proved cases of usual interstitial pneumonia (UIP) and nonspecific interstitial pneumonia (NSIP). MATERIALS AND METHODS: Consecutive patients with a diagnosis of IPF (n = 212) or asbestosis (n = 74) were included. The relationships derived from the initial comparison were tested in a separate group of biopsy-proved UIP (n = 30) and NSIP (n = 23) cases. Two observers independently scored thin-section CT images for extent, distribution, and coarseness of fibrosis; proportion of ground-glass opacification; severity of traction bronchiectasis; and extent of emphysema. RESULTS: After controlling for extent of fibrosis, patients with asbestosis had coarser fibrosis than those with IPF (odds ratio, 1.52; 95% CI: 1.25, 1.84; P <.001). Compared with the biopsy-proved cases, the asbestosis cases involved coarser fibrosis (after controlling for disease extent) than the NSIP cases (odds ratio, 2.48; 95% CI: 1.49, 4.11; P <.001) but fibrosis similar to that in the UIP cases. A basal and subpleural distribution of disease was usual in all subgroups but significantly more prevalent (P, <.01 to.001) with asbestosis than with UIP or NSIP. CONCLUSION: The thin-section CT pattern of asbestosis closely resembles that of biopsy-proved UIP and differs markedly from that of biopsy-proved NSIP.     

Resolving small pulmonary nodules: CT features

Our aim was to analyse the CT morphology of resolving nodules over time in order seek morphologic features helpful in initial nodule classification. The imaging characteristics of 133 consecutive resolving pulmonary nodules detected in 56 subjects in a screening trial for early lung cancer with low-dose CT were retrospectively reviewed by two readers in consensus. Nodule size ranged from 2 to 28 mm, with a mean diameter of 5.9 mm. The maximum diameter of resolving nodules was 5 mm in 71/133 (53%), 6–10 mm in 52/133 (39%), and >10 mm in 10/133 (8%). Their location was mainly peripheral, with a mean distance to the costal pleura of 10 mm. There was no lobe predominance of nodules. In 85% (113/133) of cases the nodules were solid, 77% (103/133) were well-defined, and 73% (97/133) were non-lobulated. Eighty percent (107/133) resolved completely within 14–1,671 (mean 492) days, 20% (26/133) resolved incompletely with residual abnormalities within 51–1,777 (mean 613) days. Resolving pulmonary nodules were mostly 10 mm, peripherally located, solid, well-defined, and non-lobulated. Most resolve completely within a variable interval ranging from several days to years.     

颈部淋巴结病变的CT灌注成像研究

目的 分析不同病理类型颈部淋巴结的CT灌注特点及鉴别诊断价值.方法 对83个经病理证实的淋巴结结核、淋巴瘤及肿瘤转移性淋巴结行多层螺旋CT灌注扫描,比较其形态学、血流方式及灌注参数等方面的差异性.3组间灌注参数及淋巴结的长径/横径(L/T)比较采用单因素方差分析和LSD检验.结果 淋巴结结核、淋巴瘤及肿瘤转移性淋巴结3组的平均通过时间(MTT)分别为(28.13±5.08)、(31.08±5.82)、(11.24±5.31)s,肿瘤转移性淋巴结的MTT值低于淋巴结结核、淋巴瘤(P值均＜0.05).3组病变边缘型血流的出现率分别为5/9、4/19、39/55(70.9%),淋巴结结核、转移性淋巴结边缘型血流的出现率高于淋巴瘤(P值均＜0.05);3组中心型血流的出现率分别为2/9、11/19、9/55(16.4%),淋巴瘤中心型血流的出现率高于肿瘤转移性淋巴结和淋巴结结核(P值均＜0.05);3组淋巴结的L/T分别为1.82±0.32、1.80±0.39、1.84±0.36;血流量(BF)分别为(34.23±5.96)、(34.00±6.88)、(35.62±10.84)ml·min-1·100 g-1;血容量(BV)分别为(24.68±2.84)、(25.30±3.16)、(25.15±8.81)ml·100 g-1;达峰时间(TTP)分别为(40.90±8.85)、(40.67±6.45)、(40.98±6.62)s;上述各参数比较差异均无统计学意义(P值均＞0.05).结论 应用CT灌注成像技术,把功能性成像与灌注血流图相结合可全面、客观地对病变做出诊断.

Abstract：

Objective To study the CT perfusion features of various lymph nodes in the neck.Methods Dynamic perfusion CT scanning was performed in 83 neck lymph nodes proved by pathology,including tuberculosis lymph nodes, lymphoma and metastatic lymph nodes. The shapes, blood flow modes,and perfusion parameters of these lymph nodes were compared among 3 groups. Statistical analysis of L/T and CT perfusion parameters was performed by one-way ANOVA and LSD test. Results The values of MTT of tuberculosis lymph nodes, lymphoma and metastatic lymph nodes were (28. 13 ±5.08), (31.08 ±5.82),and ( 11.24 ±5.31 ) s,respectively. The MTT of metastatic lymph nodes was statistically lower than that of tuberculosis lymph nodes and lymphoma (P ＜ 0. 05). Their frequencies of marginal blood flow were 5/9,4/19, and 39/55 (70. 9% ), respectively. The frequency of marginal blood flow in the tuberculosis lymph nodes and metastatic lymph nodes was statistically higher than that of lymphoma ( P ＜ 0. 05 ). Their frequencies of central blood flow were 2/9, 11/19, and 9/55 (16.4%), respectively. The frequency of central blood flow in the lymphoma was statistically higher than that of tuberculosis lymph nodes and metastatic lymph nodes ( P ＜ 0. 05 ). Their values of L/T were 1.82 ± 0. 32, 1. 80 ± 0. 39, and 1.84 ± 0. 36,(40. 98 ±6. 62) s,respectively. There were no significant differences in L/T, BF, BV and TTP among tuberculosis lymph nodes, lymphoma and metastatic lymph nodes( P ＞ 0. 05 ). Conclusion CT perfusion,especially combination functional imaging with perfusion images may be helpful in judging the nature of neck lymph nodes.     

Recent progress in computer-aided diagnosis of lung nodules on thin-section CT.

Computer-aided diagnosis (CAD) provides a computer output as a "second opinion" in order to assist radiologists in the diagnosis of various diseases on medical images. Currently, a significant research effort is being devoted to the detection and characterization of lung nodules in thin-section computed tomography (CT) images, which represents one of the newest directions of CAD development in thoracic imaging. We describe in this article the current status of the development and evaluation of CAD schemes for the detection and characterization of lung nodules in thin-section CT. We also review a number of observer performance studies in which it was attempted to assess the potential clinical usefulness of CAD schemes for nodule detection and characterization in thin-section CT. Whereas current CAD schemes for nodule characterization have achieved high performance levels and would be able to improve radiologists' performance in the characterization of nodules in thin-section CT, current schemes for nodule detection appear to report many false positives, and, therefore, significant efforts are needed in order further to improve the performance levels of current CAD schemes for nodule detection in thin-section CT.     

Predictive CT findings of malignancy in ground-glass nodules on thin-section chest CT: the effects on radiologist performance

Our purpose was to identify thin-section chest computed tomography (CT) findings of malignancy other than the presence of a solid portion within ground-glass nodules (GGNs) and to evaluate whether the radiologists’ performance in determining malignancy can be enhanced with this information. The predictive CT findings of malignancy extracted from the CT findings of 80 GGNs (47 malignant, 33 benign) were a size of >8 mm [odds ratio (OR), 10.930; P = 0.045] and a lobulated border (OR, 13.769; P = 0.016) for pure GGNs and a lobulated border (OR, 10.200; P = 0.024) for mixed GGNs. Four chest radiologists and five radiology residents participated in the observer performance study with CT of 130 GGNs (67 malignant, 63 benign). Receiver-operating characteristic (ROC) analysis was used to compare radiologists’ performances before and after providing these predictive findings. For pure GGNs, mean areas under the curve (A_z) of all readers without and with CT predictive information were significantly different (0.621 ± 0.052 and 0.766 ± 0.055, P < 0.05). For mixed GGNs, the A_z values achieved without and with predictive information were not significantly different (0.727 ± 0.064 and 0.764 ± 0.056, P > 0.05). Information about lesion size and morphological characteristics can enhance radiologists’ performance in determining malignancy of pure GGNs.     

Pancreas divisum: thin-section CT

Twelve patients with known pancreas divisum underwent thin-section computed tomography (CT) to determine the capability of CT to depict this pancreatic anomaly. Focal pancreatic enlargement was present in five patients. Two distinct pancreatic moieties separated by a fat cleft were noted in three patients; a fourth patient had focal atrophy in the distribution of the dorsal pancreas. The two pancreatic moieties were identified at the same craniocaudal level in all four of these patients. The dorsal duct was depicted in all 12 patients, while the short ventral duct was seen in only five of the 12 patients. Failure of the ventral and dorsal pancreatic ducts to fuse was identified in all five patients in whom both ducts were seen. CT may not enable specific diagnosis of pancreas divisum in the majority of patients. If, however, distinct pancreatic moieties or unfused ductal systems are evident, the diagnosis may be confidently suggested.     

Fractal analysis of small peripheral pulmonary nodules in thin-section CT: evaluation of the lung-nodule interfaces

OBJECTIVES: To analyze the lung-nodule interfaces on small peripheral pulmonary nodules (<2 cm) in thin-section CT (HRCT) images with fractal analysis. METHODS: Thin-section CT images from 70 patients with bronchogenic carcinomas (61 adenocarcinomas and 9 squamous cell carcinomas) and 47 patients with benign pulmonary nodules (23 hamartomas, 13 organizing pneumonias, and 11 tuberculomas) were used. For calculation of fractal dimensions (FDs), the authors used a box-counting method for binary- and gray-scale images of nodules. FD(two-dimensional [2D]) was an FD obtained from the binary image, and FD(three-dimensional [3D]) was an FD obtained from the gray-scale image. RESULTS: The FD(2D)s of hamartomas were smaller than those of other nodules ( < 0.05). The FD(3D)s obtained from the gray-scale images of organizing pneumonias and tuberculomas were greater than those of bronchogenic carcinomas ( < 0.0001) and hamartomas ( < 0.0001). In bronchogenic carcinomas, FD(3D)s of adenocarcinomas were greater than those of squamous cell carcinomas ( < 0.05). CONCLUSIONS: Fractal dimensions reflect the characteristics of the lung-nodule interfaces of small peripheral pulmonary nodules. The FD(2D)s revealed the irregularities of the contours. On the other hand, FD(3D)s revealed the complexities of the heterogeneous textures. With use of FD(2D) and FD(3D), it may be possible to distinguish bronchogenic carcinomas from benign pulmonary nodules. Moreover, FD(3D) may make it possible to distinguish between adenocarcinomas and squamous cell carcinomas.