Subtyping preserved ratio impaired spirometry (PRISm) by using quantitative HRCT imaging characteristics

Area of Science:

• Pulmonary Medicine
• Radiology
• Medical Imaging

Background:

• Preserved Ratio Impaired Spirometry (PRISm) is a common condition with significant health implications.
• PRISm is associated with increased respiratory symptoms, systemic inflammation, and mortality.
• Radiological studies on PRISm are limited, highlighting a gap in understanding its imaging characteristics.

Purpose of the Study:

• To investigate quantitative high-resolution computed tomography (HRCT) characteristics of PRISm.
• To evaluate the correlation between quantitative HRCT parameters and pulmonary function.
• To establish a nomogram model for predicting PRISm using quantitative HRCT.

Main Methods:

• A prospective study included 488 outpatients, with 51 diagnosed with PRISm.
• Deep inspiratory and expiratory CT scans and pulmonary function tests (PFTs) were performed.
• Automatic segmentation software (Aview) was used for quantitative analysis of lung parenchyma, airways, and vessels.

Main Results:

• Significant differences in pulmonary function parameters were observed across normal, PRISm, and mild-to-moderate COPD groups.
• Quantitative CT parameters showed differences in airways and vessels between normal and PRISm groups, and between PRISm and mild-to-moderate COPD.
• A nomogram model using smoking, mean lung density (MLD), PRMfSAD, and Lumen area predicted PRISm from normal controls with an AUC of 0.786.

Conclusions:

• PRISm exhibits distinct small airway and vessel abnormalities, resembling mild-to-moderate COPD without parenchymal attenuation.
• Quantitative HRCT parameters demonstrate predictive value for PRISm.
• The developed nomogram offers objective evidence for early PRISm screening.