Value of volumetric data acquisition in expiratory high-resolution computed tomography of the lung

The purpose of this study is to determine the potential advantages of volumetric expiratory high-resolution computed tomography (HRCT) over noncontiguous expiratory HRCT in visualizing the airway conducting to the areas of air trapping and in providing additional significant information in patients with diffuse lung disease with small airway abnormalities.

Forty-one consecutive patients with suspected diffuse lung diseases with airway abnormalities who underwent volumetric expiratory HRCT scans from April to June 2003 were studied. Respiratory motion artifacts were evaluated at 3 anatomic levels (aortic arch, carina, and lung bases). The detectability of air trapping and its conducting airway were compared on contiguous versus noncontiguous (6 evenly spaced images per patient) end-expiratory HRCT images. Additional findings on contiguous HRCT images were also assessed regarding their diagnostic significance.

The volumetric expiratory HRCT was diagnostically acceptable in 93% (38/41) of patients at arch level, 95% (39/41) at carina level, and 83% (34/41) at the lung bases, even with respiratory motion artifacts. In 35 patients with air trapping, the contiguous HRCT images enabled better identification of the conducting airway to the areas of air trapping and added diagnostically significant findings compared with noncontiguous images (P < 0.0001).

Volumetric expiratory HRCT allows for better identification of the airway conducting to the areas of air trapping compared with noncontiguous images as well as additional findings of diagnostic significance.