Noninvasive Tissue Characterization of Lung Tumors Using Integrated Backscatter Intravascular Ultrasound

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 P r = 0.53 and r = 0.67; P Conclusions Qualitative diagnosis of lung tumors was possible, with a sensitivity of 84% and a specificity of 85%, using the ultrasound IBS technique.