Pulmonary nodules with ground-glass opacity can be reliably measured with low-dose techniques regardless of iterative reconstruction: results of a phantom study.

OBJECTIVE. Pulmonary nodules of ground-glass opacity represent one imaging manifestation of a slow-growing variant of lung cancer. The objective of this phantom study was to quantify the effect of the radiation dose used for the examination (volume CT dose index [CTDIvol]), type of reconstruction algorithm, and choice of postreconstruction enhancement algorithms on the measurement error when assessing the volume of simulated lung nodules with CT, focusing on two radiodensity levels. MATERIALS AND METHODS. Twelve synthetic nodules of two radiodensities (−630 and −10 HU), three shapes (spherical, lobulated, and spiculated), and two sizes (nominal diameters of 5 and 10 mm) were inserted into an anthropomorphic chest phantom and scanned with techniques varying in CTDIvol (from subscreening dose [0.8 mGy] to diagnostic levels [6.5 mGy]), reconstruction algorithms (iterative reconstruction and filtered back projection), and different postreconstruction enhancement algorithms. Nodule volume was measured from the...