[Intravascular ultrasound in preoperative diagnosis of central bronchial tumors--initial clinical experiences]

In the course of preoperative diagnosis, intravasal sonography for tumour imaging was conducted in three patients suffering from central bronchial carcinoma. The catheters of 6.0 or 4.8 French diameter were advanced in each case after pulmonary angiography via the left or right pulmonary artery up to the tumour area. Endosonographic tumour imaging was compared with the findings of the other preoperative diagnostic measures and in two cases with intraoperative and postoperative findings. The vascular walls of the central pulmonary arterial segments showed sonographically no typical three-layer structure. In all cases, however, tumour infiltration was showed up by disappearance of the vascular wall reflexes in the relevant pulmonary artery branches. Visualisation of the mediastinal pulmonary artery segments or of the main stem of the pulmonary artery is difficult with the wire-guided catheters used, since these cannot be stabilised in the centre of the vessel. Development of suitable catheters with low-frequency transducers and greater depth of penetration is imperative especially for the diagnostically important visualisation of the surrounding mediastinal structures.