title: Noninvasive Tissue Characterization of Lung Tumors Using Integrated Backscatter Intravascular Ultrasound: An Ex Vivo Comparative Study With Pathological Diagnosis.
abstract: BACKGROUND
  Endobronchial ultrasonography (EBUS) facilitates a lung cancer diagnosis. However, qualitative tissue characterization of lung tumors is difficult using EBUS. Integrated backscatter (IBS) is an ultrasound technique that calculates the power of the ultrasound signal to characterize tissue components in coronary arteries. We hypothesized that qualitative diagnosis of lung tumors is possible using the IBS technique. The aim of the present study was to elucidate whether the IBS technique can be used in lung tissue diagnoses.
  
  
  METHODS
  Thirty-five consecutive patients who underwent surgery for lung cancer were prospectively enrolled. Surgical specimens of the lung and the tumor tissue were obtained, and the IBS values were measured within 48 h after surgery. Histologic images of lung and tumor tissues were compared with IBS values, and the relative interstitial area according to results of Masson's trichrome staining were determined by using an imaging processor.
  
  
  RESULTS
  The IBS values in tumor tissue were significantly lower than those in normal lung tissue (-50.9 ± 2.6 dB and -47.6 ± 2.6 dB, respectively; P < .001). The IBS values of adenocarcinomas associated with a good 5-year survival rate were higher than those of non-adenocarcinomas (-48.1 ± 1.6 dB and -52.6 ± 1.4 dB; P < .001). There were significant correlations between the IBS values and the relative interstitial area or micro air area in tumor (r = 0.53 and r = 0.67; P < .01). After combining normal lung tissue and adenocarcinomas with a good prognosis, the sensitivity and specificity for establishing the presence of lung tumors were 84% and 85%.
  
  
  CONCLUSIONS
  Qualitative diagnosis of lung tumors was possible, with a sensitivity of 84% and a specificity of 85%, using the ultrasound IBS technique.
authors.affiliation: Department of Respirology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Fumitaka
authors.initials: F
authors.lastname: Ito
authors.affiliation: Department of Cardiology, Gifu University Graduate School of Medicine, Gifu, Japan. Electronic address: masanori@ya2.so-net.ne.jp.
authors.forename: Masanori
authors.initials: M
authors.lastname: Kawasaki
authors.affiliation: Department of Respirology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Ohno
authors.affiliation: Department of Respirology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Sayaka
authors.initials: S
authors.lastname: Toyoshi
authors.affiliation: Department of Respirology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Megumi
authors.initials: M
authors.lastname: Morishita
authors.affiliation: Department of Respirology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Daizo
authors.initials: D
authors.lastname: Kaito
authors.affiliation: Department of Respirology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Komei
authors.initials: K
authors.lastname: Yanase
authors.affiliation: Department of Respirology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Norihiko
authors.initials: N
authors.lastname: Funaguchi
authors.affiliation: Department of Respirology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Asano
authors.affiliation: Department of Respirology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Junki
authors.initials: J
authors.lastname: Endo
authors.affiliation: Department of Respirology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Hidenori
authors.initials: H
authors.lastname: Mori
authors.affiliation: Pathology Division, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kobayashi
authors.affiliation: Department of Cardiology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Nishigaki
authors.affiliation: Pathology Division, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Tatsuhiko
authors.initials: T
authors.lastname: Miyazaki
authors.affiliation: Department of Cardiology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Genzou
authors.initials: G
authors.lastname: Takemura
authors.affiliation: Department of Cardiology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Minatoguchi
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D000368:Aged; D001999:Bronchoscopy; D018287:Carcinoma, Large Cell / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D018278:Carcinoma, Neuroendocrine / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D019160:Endosonography; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018084:Ultrasonography, Interventional / Q000295:instrumentation*
keywords: endobronchial ultrasonography; integrated backscatter ultrasound; lung tumor; tissue characterization