Research on the respiratory frequency changes of 4DCT reconstructed image

Abstract

Objective To study the impact of respiratory frequency and amplitude of patients with the thoracic or abdomen tumor on 4DCT's reconstructed image. Methods 75 thoracic or abdomen tumor patients who performed a scanning with belly belt-type respiratory gating on 4DCT between November 2012 to March 2013 in our hospital were retrieved. Reviewed their respiratory frequency, amplitude and fault distance of 4DCT's reconstructed image and analyzed the correlation fault distance of the reconstructed image. The correlation analysis was used by bivariate Spearman method. Results Among these reconstructed images, fault distance more than 6 mm could be seen in 11 cases, fault distance ranging from 3 mm to 6 mm could be found in 46 cases, and distance less than 3 mm could be detected in 18 case. Respiratory frequency correlated significantly with the amplitude (rs=0.369, P=0.000); the respiratory rate had a tight association with the fault distance of the reconstructed image (rs=0.273, P=0.018); and respiratory amplitude was associated obviously with the fault distance of the reconstructed image (rs=0.696, P=0.000). Conclusions Both 4DCT reconstructed image and respiratory amplitude are significantly correlated to the continuity of the respiratory frequency. The smaller the respiratory frequence and amplitude change are, the better continuity will be. Key words: Tomography, X-ray computed, four-dimensional; Respiratory frequency; Respiratory amplitudes; Reconstructed image