10 MHz ultrasound linear array catheter for endobronchial imaging

This paper presents the acoustical design, manufacture and evaluation of an ultrasound catheter array for endobronchial imaging. In order to be used in an existing bronchofiberscope, the 64 elements transducer is included in a 7 French (2.3 mm OD) catheter, using a ribbon-based cabling technology. The ultrasound array has a 200 /spl mu/m pitch, a 1.5 mm elevation, and operates at 10 MHz center frequency. The piezoelectric material is based on 1-3 piezo-composite technology and the front layer (optimized multilayer stack of passive materials) is selected to act both as a matching and protection layer. The probe is integrated into the catheter and interfaced to a commercial ultrasound system. The paper also reviews electro-acoustical characteristics including sensitivity, frequency, bandwidth and homogeneity performances. The aim of this probe is the detection of epithelial abnormalities, transparietal extension of lesions and detection of lymph nodes related to local cancer. Finally, in vivo images obtained through a bronchofiberscope are presented and discussed from a clinical point of view.