CT imaging of the patulous eustachian tube--comparison between sitting and recumbent positions. 
The objective was to evaluate the three-dimensional anatomy of the eustachian tube (ET) and its surrounding tissues of patulous ET patients in the sitting positions by the horizontal computed tomography (CT) system with the multiplanar reconstruction (MPR) technique, and to compare the findings with those obtained in the recumbent position.  Two patients with severe bilateral patulous ET were investigated.  After performing temporal bone CT examination both in the sitting and recumbent position, MPR images of the ET were reconstructed and measurement was made on a workstation.  The ET lumen was identified at most of the portion from the pharyngeal orifice to the tympanic orifice in both positions.  At the cartilaginous portion, the air space in the ET lumen was larger in the sitting position than in the recumbent position.  At the bony portion of the ET, there did not seem to be any significant difference in the results of measurement in both cases.  For the first time, we were able to obtain reconstructed images of patulous ET patients in the sitting position and to compare the findings with those of the recumbent position.  We suggest that this method is useful for better understanding of the ET and ET-related diseases such as patulous ET.