title: Three-dimensional high-frequency backscatter and envelope quantification of cancerous human lymph nodes.
abstract: Quantitative imaging methods using high-frequency ultrasound (HFU) offer a means of characterizing biological tissue at the microscopic level. Previously, high-frequency, 3-D quantitative ultrasound (QUS) methods were developed to characterize 46 freshly-dissected lymph nodes of colorectal-cancer patients. 3-D ultrasound radiofrequency data were acquired using a 25.6 MHz center-frequency transducer and each node was inked before tissue fixation to recover orientation after sectioning for 3-D histological evaluation. Backscattered echo signals were processed using 3-D cylindrical regions-of-interest (ROIs) to yield four QUS estimates associated with tissue microstructure (i.e., effective scatterer size, acoustic concentration, intercept and slope). These QUS estimates, obtained by parameterizing the backscatter spectrum, showed great potential for cancer detection. In the present study, these QUS methods were applied to 112 lymph nodes from 77 colorectal and gastric cancer patients. Novel QUS methods parameterizing the envelope statistics of the ROIs using Nakagami and homodyned-K distributions were also developed; they yielded four additional QUS estimates. The ability of these eight QUS estimates to classify lymph nodes and detect cancer was evaluated using receiver operating characteristics (ROC) curves. An area under the ROC curve of 0.996 with specificity and sensitivity of 95% were obtained by combining effective scatterer size and one envelope parameter based on the homodyned-K distribution. Therefore, these advanced 3-D QUS methods potentially can be valuable for detecting small metastatic foci in dissected lymph nodes.
authors.affiliation: F. L. Lizzi Center for Biomedical Engineering, Riverside Research Institute, New York, NY 10038, USA. jmamou@riversideresearch.org
authors.forename: Jonathan
authors.initials: J
authors.lastname: Mamou
authors.forename: Alain
authors.initials: A
authors.lastname: Coron
authors.forename: Michael L
authors.initials: ML
authors.lastname: Oelze
authors.forename: Emi
authors.initials: E
authors.lastname: Saegusa-Beecroft
authors.forename: Masaki
authors.initials: M
authors.lastname: Hata
authors.forename: Paul
authors.initials: P
authors.lastname: Lee
authors.forename: Junji
authors.initials: J
authors.lastname: Machi
authors.forename: Eugene
authors.initials: E
authors.lastname: Yanagihara
authors.forename: Pascal
authors.initials: P
authors.lastname: Laugier
authors.forename: Ernest J
authors.initials: EJ
authors.lastname: Feleppa
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D002277:Carcinoma / Q000000981:diagnostic imaging* / Q000556:secondary*; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D016247:Information Storage and Retrieval / Q000379:methods*; D008198:Lymph Nodes / Q000000981:diagnostic imaging*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012542:Scattering, Radiation; D012680:Sensitivity and Specificity; D013274:Stomach Neoplasms / Q000000981:diagnostic imaging*; D014463:Ultrasonography