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In vitro investigation of detectability of colorectal lymph nodes and diagnosis of lymph node metastasis in colorectal cancer using B‐mode sonography
Author(s) -
Tateishi Tsutomu,
Machi Junji,
Feleppa Ernest J.,
Oishi Andrew J.,
Furumoto Nancy L.,
Oishi Robert H.,
McCarthy Laurence J.,
Yanagihara Eugene,
Shirouzu Kazuo
Publication year - 2004
Publication title -
journal of clinical ultrasound
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.272
H-Index - 61
eISSN - 1097-0096
pISSN - 0091-2751
DOI - 10.1002/jcu.10210
Subject(s) - medicine , lymph , echogenicity , colorectal cancer , lymph node , metastasis , receiver operating characteristic , radiology , ultrasound , pathology , cancer
Purpose The aim of this in vitro study was to assess the feasibility of using high‐frequency sonography to identify colorectal lymph nodes and to diagnose colorectal lymph node metastasis. Methods In part 1 of this study, resected colorectal tissues from 13 patients with colorectal cancer were scanned in a water bath using B‐mode sonography performed at high frequency (10 MHz) to identify lymph nodes. The colorectal tissues were then carefully dissected to remove all lymph nodes. Detectability was calculated as the ratio of the number of sonographically detected nodes to the total number of histopathologically confirmed nodes. Student's t test was performed to compare sizes between these groups; a p value of less than 0.05 was considered significant. In part 2, 4 features of lymph nodes identified on B‐mode sonography—size, shape, border, and echogenicity—and their combinations were evaluated for their ability to diagnose lymph node metastasis. Discriminant and receiver operating characteristic curve analyses were performed. Results In part 1, B‐mode sonography performed in vitro detected 79 (48%) of the 165 histopathologically identified lymph nodes and 34 (87%) of the 39 histopathologically identified metastatic nodes. The mean size, or mean longest axis (± standard deviation), of the sonographically detected nodes (6.4 ± 2.9 mm) was significantly larger than that of undetected nodes (3.6 ± 1.7 mm; p < 0.01). In part 2, the most effective feature distinguishing metastatic from nonmetastatic lymph nodes was echogenicity, followed by size, shape, and border. However, a combination of at least 2 features (eg, echogenicity and size) provided better distinction of nodes than did any 1 feature. In the receiver operating characteristic curve of the 4‐feature combination, an increase in sensitivity is accompanied by a decrease in specificity: at a sensitivity of 100%, specificities decreased to 60% or less. However, even with the optimal combination of features, the sensitivity and specificity did not both reach 85% at any operating point. Conclusions The results of this node‐by‐node in vitro study show the current limitations and potential of sonography for assessing colorectal lymph nodes. High‐frequency sonography may be insufficient for identifying lymph node metastasis in colorectal cancer. © 2003 Wiley Periodicals, Inc. J Clin Ultrasound 32:1–7, 2004