# Discrepant Results of Post-valve CT Analysis and Pulmonary Function Test in Patients Undergoing Bronchoscopic Lung Volume Reduction

## TL;DR

This study found that pulmonary function tests showed greater volume reduction after a lung treatment than CT scans, suggesting a mismatch between anatomical and functional assessments.

## Contribution

The study highlights a discrepancy between CT and PFT in measuring post-BLVR outcomes, emphasizing the potential underestimation by CT.

## Key findings

- PFT showed a -6% total volume change compared to -3% from CT after BLVR.
- PFT reported a -490 mL volume change versus -247 mL from CT analysis.
- No linear correlation was found between CT and PFT volume changes (p = 0.315, R2 = 0.101).

## Abstract

Introduction

Emphysema is a debilitating form of chronic obstructive pulmonary disease (COPD) that causes lung hyperinflation and air trapping, leading to reduced quality of life. Bronchoscopic lung volume reduction (BLVR) with endobronchial valves (EBVs) offers a minimally invasive treatment option by collapsing diseased lung segments to improve respiratory mechanics. While both CT and pulmonary function testing (PFT) are used to assess outcomes, it remains unclear whether post-procedural volume changes measured by CT correlate with functional improvements seen on PFT.

Materials and methods

We performed a single-center chart review of patients who underwent BLVR with EBV from January 2019 to December 2023 who had both pre-and post-procedure PFT and CT volume analysis performed. Data recorded included clinical and demographic characteristics, post-valve analysis, and PFT.

Results

A total of 14 patients were included in our study. A comparison of total lung volume change between post-BLVR CT analysis and PFT showed a -3% total volume change in post-BLVR CT analysis versus -6% total volume change in PFT. Post-BLVR CT analysis showed a median volume change of -247 mL versus PFT with -490 mL volume change. The volume change in PFT and post-BLVR CT analysis did not show a linear correlation (p = 0.315, R2 = 0.101).

Conclusions

Our study found that post-BLVR pulmonary function testing showed greater volume reduction and functional improvement compared to CT analysis, suggesting a discrepancy between anatomical and physiological assessments. These findings indicate that CT may underestimate therapeutic response, and PFT may be a more reliable tool for evaluating clinical outcomes after EBV placement.