Upper abdominal lymph nodes: criteria for normal size determined with CT

Reports of the upper limits of normal for lymph node size at abdominal computed tomography have varied from 6 to 20 mm. Establishment of an upper limit for node size by specific location, analogous to that which has been reported for mediastinal lymph nodes, was sought. Short-axis diameters of the lymph nodes were measured in 130 patients who were not likely to have enlarged abdominal lymph nodes. Seven locations were defined, and the largest nodal measurement for each was recorded. Histographic analysis and nonparametric statistical methods were used to determine threshold values for the maximum node size in each region. The upper limits of normal by location were as follows: retrocrural space, 6 mm; paracardiac, 8 mm; gastrohepatic ligament, 8 mm; upper paraaortic region, 9 mm; portacaval space, 10 mm; porta hepatis, 7 mm; and lower paraaortic region, 11 mm. Lower paraaortic lymph nodes larger than 11 mm by short-axis measurement are abnormal. In other locations, nodes smaller than 1 cm may be abnormal if the determined thresholds are exceeded.     

Change of sonographic findings on cervical lymph nodes before and after preoperative radiotherapy

The aim of this study was to assess the changes in the power Doppler sonographic findings in patients with oral cancer undergoing chemotherapy and radiotherapy. We performed US examinations on 187 cervical lymph nodes (71 metastatic and 116 reactive nodes) excised from 52 patients before and after preoperative therapy. On Power Doppler images, we calculated the vascular index (VI) and evaluated the vascular pattern. We also assessed the diagnostic power using receiver operating characteristic (ROC) curve analysis. Irradiation caused an increase of the VI and better visualization of the vessels within the lymph node in the reactive nodes; however, in the metastatic nodes, the VI was not significantly different between that before and after irradiation. When the reader observed the images before irradiation, the area under an ROC curve (Az values) observed by B-mode sonography were closely similar to those obtained by B-mode plus power Doppler sonography. With both images before and after irradiation, the Az value obtained by B-mode plus power Doppler sonography was higher than that by B-mode sonography alone. After irradiation, the enhanced Doppler signals contributed to a better visualization of the vessels and a better detection of any vascular abnormalities.     

The number and size of normal mediastinal lymph nodes: a postmortem study

For the CT diagnosis of pathologically enlarged nodes, information concerning the size of normal nodes is required. We studied 40 adult cadavers and determined the number and size of normal lymph nodes for each region of the mediastinum, counting all nodes and directly measuring the short and long diameters of each in the transverse plane of the node. The location of each node was classified according to the American Thoracic Society system, and the range and standard maximum sizes of normal lymph nodes in each location were determined. Nodes were found in 90-100% of cadavers in regions 4, 7, and 10; and in 68-85% of cadavers in regions 2 and 6. The average number of lymph nodes found was 3.5-4.8 in regions 4, 6, and 10R; 2.1-2.9 in regions 2, 7, and 10L; and 0.1-1.2 in all other regions. The mean short transverse diameters ranged from 2.4 to 5.6 mm, and the mean long transverse diameters ranged from 3.9 to 10.0 mm. The largest mean short and long transverse diameters were found in region 7, the next largest were in region 10R, followed by regions 4, 5, and 10L. We noted a different maximum normal size of lymph nodes in each region of the mediastinum. The short transverse diameter, which showed a smaller variation, appeared to be a more useful parameter than the long transverse diameter. We propose a standard for maximum normal short transverse diameters for nodes in each region of the mediastinum as follows: 12 mm for nodes in region 7; 10 mm for nodes in regions 4 and 10R; and 8 mm for nodes in other regions. The maximum long transverse diameters showed a wider variation, ranging from 25 to 10 mm.     

Detection of suspicious malignant cervical lymph nodes of unknown origin: diagnostic accuracy of ultrasound-guided fine-needle aspiration biopsy with nodal size and central necrosis correlate.

OBJECTIVE: To assess the role of ultrasound-guided fine-needle aspiration biopsy (US-guided FNAB) in the diagnostic workup of suspicious malignant cervical lymph nodes in patients with palpable neck masses and without known primary cancer. The diagnostic accuracy of imaging morphologic criteria, including sizes and central necrosis for assessing suspicious malignant nodes, were also examined. METHODS: This is a retrospective study of 426 patients with palpable neck masses from an outpatient department evaluated with computed tomography, magnetic resonance imaging, or US. US-guided FNABs were performed in 102 patients with suspicious malignant cervical lymph nodes at a single institution. Cytologically positive lymph nodes (n = 12) were further validated with excisional biopsy. Negative lymph nodes (n = 90) were either excised (n = 10) or followed up by imaging studies for at least one year (n = 80). The diagnostic accuracy of the FNABs along with the imaging findings of nodal sizes and presence of central necrosis, which were classified by a consensus of 2 radiologists, were assessed. RESULTS: Twelve malignant nodes were detected with US-guided FANB with one false-positive and one false-negative result. The overall sensitivity, specificity, and accuracy for FNAB were 91.7%, 98.9%, and 98.0%, respectively. The sensitivity, specificity, and accuracy were 66.7%, 30.0%, and 34.3% for size criterion and 75.0%, 83.3%, and 82.3% for central necrosis criterion. CONCLUSIONS: The size of cervical lymph node does not appear to be an important imaging criterion for assessing suspicious malignant lymph nodes, compared with the criterion of central necrosis. US-guided FNAB is highly specific and sensitive in the diagnostic workup of suspicious malignant cervical lymph nodes in patients without known primary cancers.     

Sonography of neck lymph nodes. Part I: normal lymph nodes

Grey scale and power Doppler sonography play an important role in assessment of cervical lymphadenopathy. However, before examination of pathological nodes, a clear understanding of the anatomy of cervical nodes, scanning technique and sonographic appearances of normal cervical nodes is essential. This article reviews these topics in order to provide a baseline for sonographic examination of cervical lymphadenopathy.     

Central nodal necrosis and extracapsular neoplastic spread in cervical lymph nodes: MR imaging versus CT.

Computed tomographic (CT) scans and magnetic resonance (MR) images obtained in 24 patients with cervical lymphadenopathy were retrospectively and blindly evaluated by two readers for the presence of central nodal necrosis (CNN) and extracapsular nodal spread (ENS). The CT studies were all enhanced, and the MR images were obtained with short repetition time (TR)/echo time (TE), long TR/double echo, and enhanced short TR/TE fat-suppressed sequences. Each MR imaging sequence was interpreted separately and then collectively. Sixty lymph nodes were identified with CT. Sensitivity for CNN was 16%-67% with the unenhanced MR pulse sequences, 50% with enhanced sequences, and 83%-100% with CT. The most accurate reading of MR images for CNN was with the unenhanced T1-weighted and T2-weighted images (86%-87%); the accuracy of CT was 91%-96%. The accuracy of MR imaging for detecting ENS was maximal with T1-weighted images (78%-90%). Gadolinium-enhanced, fat-suppressed images did not improve accuracy in evaluating CNN or ENS. CT is currently more accurate than unenhanced or enhanced MR imaging in detecting CNN or ENS.     

Multivariate feature analysis of sonographic findings of metastatic cervical lymph nodes: contribution of blood flow features revealed by power Doppler sonography for predicting metastasis

BACKGROUND AND PURPOSE: Sonographic criteria of the lymph node have been found to be good indicators for metastatic lymph nodes. We determined which sonographic features are most predictive of metastasis in cervical lymph nodes among patients with head and neck cancer. METHODS: Gray-scale and power Doppler sonograms were retrospectively analyzed in 133 cervical lymph nodes (57 metastatic and 76 reactive nodes) from 52 patients with head and neck cancer. The gray-scale sonographic features of the presence or absence of hilar echoes, parenchymal echogenicity, and short and long axis lengths as well as the power Doppler features of normal hilar flow and abnormal parenchymal flow were evaluated. Univariate and multivariate logistic regression analyses were conducted to determine the relative value of each sonographic feature. RESULTS: At univariate analysis, all sonographic features assessed were found to be important. Multivariate analysis, however, suggested that the presence or absence of hilar echoes, increases in short axis length, and the presence of normal hilar flow were the only sonographic features that were predictive of reactive (presence of hilar echoes and hilar flow) and metastatic (increases in short axis length) lymph nodes. Although multivariate analysis did not indicate any significant contribution of the color-flow criteria for predicting metastatic nodes, the color-flow criteria appeared to improve the overall diagnostic accuracy for the less experienced observer. CONCLUSION: The sonographic criteria most predictive of metastatic cervical lymph nodes were absent hilar echoes and increases in short axis length, as assessed by logistic regression analysis. Compared with these gray-scale criteria, color-flow criteria had fewer predictive advantages.     

Sonographic evaluation of cervical lymph nodes

OBJECTIVE: Sonography is a useful imaging tool in the evaluation of cervical lymph nodes. Gray-scale sonography and color and power Doppler sonography are commonly used in clinical practice. This article documents the common sonographic appearances of different causes of cervical lymphadenopathy. CONCLUSION: The sonographic appearances of normal nodes differ from those of abnormal nodes. Sonographic features that help to identify abnormal nodes include shape (round), absent hilus, intranodal necrosis, reticulation, calcification, matting, soft-tissue edema, and peripheral vascularity.     

Quantitative evaluation of vascularity within cervical lymph nodes using Doppler ultrasound in patients with oral cancer: relation to lymph node size

Objectives

The aim of this study was to quantitatively evaluate the relationship between vascularity within lymph nodes and lymph node size on Doppler ultrasound images of patients with oral cancer.

Methods

A total of 310 lymph nodes (86 metastatic, 224 benign) from 63 patients with oral cancer were classified into 4 groups according to their short axis diameters: Group 1, short axis diameters of 4–5 mm; Group 2, 6–7 mm; Group 3, 8–9 mm; and Group 4, ≥10 mm. Vascular and scattering indices of lymph nodes on Doppler ultrasound images were analysed quantitatively. The vascular index was defined as the ratio of blood flow area to the whole lymph node area and the scattering index was defined as the number of isolated blood flow signal units.

Results

For metastatic lymph nodes, the vascular index was highest in Group 1 and decreased as lymph node size increased. The vascular index of benign lymph nodes did not differ significantly among the four groups. The vascular index of metastatic lymph nodes was significantly higher than that of benign lymph nodes in Group 1. For metastatic lymph nodes, the scattering index increased as lymph node size increased and was significantly higher than that of benign lymph nodes in Groups 2–4.

Conclusions

An increase in vascularity is a characteristic of Doppler ultrasound findings in small metastatic lymph nodes. As the metastatic lymph node size increases, blood flow signals become scattered, and the scattering index increases.     

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.     

Size of normal retroperitoneal lymph nodes

The CT diagnosis of diseases in the retroperitoneal lymph nodes is based mainly on an evaluation of the size of the nodes in the transverse plane. Opinions on the normal size of the nodes vary, however. With the aim of obtaining a normal material, the diameters of the lymph nodes were measured on lymphograms that had been considered to be normal, from 95 patients. The upper limit for the diameter is not the same for all lymph nodes, but varies with the position of the node in the para-aortic chains, ranging from 7 to 15 mm, with increasing diameters in the caudal direction.     

Differentiation between benign and metastatic cervical lymph nodes with ultrasound

Objective:

The differentiation between benign and metastatic lymph nodes with ultrasound (US) is based primarily on the evaluation of size, shape, margin and internal echo structure. The aim of this study is to determine whether these parameters are reliable indicators and to correlate internal echo structure and histopathological findings.

Materials and Methods:

Seventy-one nodes in 21 patients with pathologically proven oral squamous cell carcinoma were examined. The shortest diameter, the short/long diameter ratio (S/L ratio), margins and internal echo structure of the lymph node were evaluated by US. The internal echo structure was divided into six patterns: homogeneous hypoechoic, homogeneous hyperechoic, heterogeneous, eccentric hyperechoic, centric hyperechoic and anechoic pattern. In addition, internal echo structure was correlated with histopathological findings.

Results:

In 71.4% of the metastatic nodes, the shortest diameter was more than 10 mm and the S/L ratio was higher than that of benign nodes (average 0.71). Eleven (84.6%) of the 13 lymph nodes with irregular margins were metastatic. Heterogeneous and anechoic patterns were observed in metastatic nodes, whereas homogeneous hypoechoic and eccentric hyperechoic patterns were present in benign nodes. On ultrasonography with the corresponding histopathological findings, echogenic areas in the homogeneous hyperechoic, heterogeneous and centric hyperechoic patterns of metastatic nodes proved to be necrosis or fibrosis. Eccentric hyperechoic areas in benign nodes corresponded to the hilus and surrounding fatty tissue.

Conclusions:

The shortest diameter, S/L ratio, margin and internal echo structure were considered to be critical indicators to differentiate between benign and metastatic nodes. Secondary changes caused by tumour infiltration, necrosis, or fibrosis should be assessed when metastatic lymph nodes are differentiated from benign ones by internal echo structure.     

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.     

Metastatic intramammary lymph nodes: mammographic and ultrasonographic features.

OBJECTIVE: To evaluate the mammographic and ultrasonographic findings in patients with intramammary lymph node (IMLN) involvement in breast cancer. MATERIALS AND METHODS: The mammograms of 1655 histopathologically proven breast cancer cases diagnosed during the last 10 years were retrospectively reviewed. There were 16 cases in which metastasis to intramammary lymph nodes was suspected mammographically and proven histopathologically. The clinical and radiological features of these 16 cases were evaluated. RESULTS: On mammograms, the involved lymph nodes were all well circumscribed, homogeneous, oval or round opacities in the upper outer quadrant of the breast. They were all larger than 1 cm in size. On US, they were seen as well circumscribed, homogeneously hypoechoic masses with mild acoustic enhancement. In one case, besides enlargement, development of malignant microcalcifications was seen inside the node in the follow up period. In another case with IMLN metastasis, the primary focus of the breast cancer could not be detected either mammographically or histopathologically. So the case was accepted as occult breast carcinoma. All of the primary tumors detected were invasive histopathologically and their sizes varied between 1-6 cm (mean, 3 cm). CONCLUSION: The involvement of the IMLN can be suspected with mammographic and ultrasonographic features. Metastatic disease from breast cancer to IMLN may be the first clinical and/or radiological sign of breast cancer.     

Intrapulmonary lymph nodes: thin-section CT features of 19 nodules

PURPOSE: The purpose of this study was to describe the thin-section CT features of intrapulmonary lymph nodes that accompanied primary or metastatic lung tumors. METHOD: A retrospective analysis of thin-section CT features was performed on 19 nodules in 16 patients with pathologically confirmed intrapulmonary lymph nodes that accompanied primary or metastatic lung tumors. RESULTS: Of the 16 patients, 13 had a solitary nodule and 3 had two nodules. All nodules were distributed in the middle lobe, lingula, or lower lobe. On thin-section CT images, the nodule was located abutting the visceral pleura (n = 10) or within 8 mm of the visceral pleura (n = 9). The thin-section CT findings showed that most of the nodules were well circumscribed (n = 18), homogeneous (n = 19), ovoid (n = 10), or round (n = 9) and smaller than 12 mm in maximal diameter. The surrounding lung field was normal (n = 16). CONCLUSION: Intrapulmonary lymph nodes are subpleural in the lower lung field. On thin-section CT, they are well circumscribed, homogeneous, round or ovoid, and smaller than 12 mm in maximal diameter. In the differential diagnosis of subpleural nodules located in the lower lung field, it should be kept in mind that they may be intrapulmonary lymph nodes even though the patient has malignancy.     

Sensitivity and specificity of sonographic diagnosis of the lymph nodes in malignant melanoma

A total of 213 melanoma patients were checked perioperatively with a 5-MHz sonographic scanner in order to detect lymph-node metastases; they were also checked in the scope of tumor follow-up. Of the 415 sonographic results, the method yielded a 97% accuracy. The soundness of lymph-node sonography has been proved histologically and/or through clinical observation. Compared to the other diagnostic techniques available for checking surface and subsurface lymph-node groups, lymph-node sonography is an advantageous combination of diagnostic practicability, accuracy, economic feasibility, and patient acceptance. The possible therapeutic implications are also discussed in this paper.     

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.