The effects of computed tomography with iterative reconstruction on solid pulmonary nodule volume quantification

Area of Science:

• Radiology
• Medical Imaging
• Pulmonology

Background:

• Pulmonary nodules require accurate volume assessment for clinical management.
• Computed tomography (CT) is a primary imaging modality for nodule detection and characterization.
• Iterative reconstruction (IR) techniques aim to reduce radiation dose while maintaining image quality in CT.

Purpose of the Study:

• To evaluate the impact of iterative reconstruction (IR) on the accuracy of pulmonary nodule volumetry using chest CT.
• To compare volumetric measurements obtained with IR against standard filtered back projection (FBP).

Main Methods:

• Twenty patients with pulmonary nodules underwent chest CT using a 64-slice scanner.
• Data were reconstructed using filtered back projection (FBP) and iterative reconstruction (IR) at various levels (iDose(4)-levels 2, 4, 6) at similar radiation doses.
• Semi-automatic software was used for volumetric nodule measurements on thin slice reconstructions of solid nodules.

Main Results:

• No significant differences in measured pulmonary nodule volumes were observed between FBP and IR (levels 2, 4, 6) for both small (<200 mm³) and large (≥200 mm³) nodules.
• High concordance (pc-values ≥0.98) was found between FBP and all IR levels for both nodule sizes.
• Excellent intra-observer and inter-observer variability (pc-values ≥0.98) was demonstrated.

Conclusions:

• Iterative reconstruction (IR) provides pulmonary nodule volumetry results comparable to standard filtered back projection (FBP).
• The level of IR used did not significantly affect the measured volumes of small or large solid pulmonary nodules.
• IR can be reliably used for pulmonary nodule volumetry in chest CT without compromising accuracy compared to FBP.