Pulmonary emphysema: radiation dose and section thickness at multidetector CT quantification--comparison with...

Area of Science:

• Radiology
• Pulmonary Medicine
• Medical Imaging

Background:

• Pulmonary emphysema quantification using multidetector computed tomography (CT) is essential for diagnosis and management.
• Assessing the impact of varying radiation doses and section thicknesses on CT-based emphysema metrics is critical for optimizing imaging protocols.

Purpose of the Study:

• To prospectively evaluate how radiation dose and section thickness influence quantitative CT indexes used to measure pulmonary emphysema.

Main Methods:

• Seventy patients underwent multidetector CT at different radiation doses (20 and 120 effective mAs) and reconstructed section thicknesses (1.25, 5.0, 10.0 mm).
• Relative areas (RAs) of lung with low attenuation coefficients were compared with histopathologic emphysema extent (mean interwall distance, mean perimeter).
• Spearman correlation coefficients were used to analyze the relationship between CT parameters and histopathology.

Main Results:

• The 1st percentile and attenuation thresholds of -960/-970 HU showed the strongest correlation with emphysema extent, irrespective of dose or thickness.
• Both radiation dose and section thickness significantly affected RAs for thresholds -960/-970 HU.
• Section thickness significantly impacted the 1st percentile, while radiation dose did not.

Conclusions:

• Tube current-time product can be reduced to 20 mAs for CT quantification of pulmonary emphysema.
• Consistency in tube current-time product and section thickness is vital for reliable follow-up examinations in emphysema assessment.