Routine use of a higher order interpolator and bone algorithm in thoracic CT

This study was designed to evaluate the utility of the routine use of high spatial frequency algorithms and higher order helical interpolators for imaging lung parenchyma during routine thoracic CT. We evaluated 50 consecutive patients undergoing clinically indicated thoracic CT using the same imaging parameters and scanner. The helical volume was reconstructed three separate times using standard and higher order (180 degrees linear with double-sided lobes) interpolators and standard and high spatial frequency (bone) algorithms. The images were photographed and given to five separate readers who were kept unaware of the interpolator and algorithm and who were asked to evaluate simultaneously each patient's three sets of images for best, in-between, and worst images of the lung interstitium, pathology, and normal anatomy. All five readers rated the standard interpolator and algorithm images as the worst (p < .01). All five readers consistently rated the double-sided lobe interpolator and bone algorithm images as the best (p < .01). A second reconstruction of routine thoracic helical CT data using higher order helical interpolators and a bone algorithm significantly improves interstitial detail of lung parenchyma and overall visualization of normal anatomy and pathologic processes.