Abstract
Background The Pulmonary Radioaerosol Mucociliary Clearance (PRMC) is a reliable method for assessing in vivo whole lung mucociliary clearance (MC) and used at the Danish PCD Centre as a supplementary diagnostic test for primary ciliary dyskinesia (PCD) for more than two decades. This study aimed to investigate genotype-specific differences in PRMC measures and evaluate its potential as outcome parameter.
Material and Methods The study was based on a retrospective analysis on PRMC tests performed over a 24-year period (1999–2022) in individuals referred for PCD work-up and included patients with genetically confirmed PCD and non-PCD controls. Nebulized 99mTc-albumin-colloid was inhaled, and static and dynamic imaging following obtained. Three parameters were evaluated: 1-hour lung retention (LR1), tracheobronchial velocity (TBV), and cough clearance.
Results The study included 69 patients from the Danish PCD cohort, representing 26 different PCD genotypes. MC by PRMC was consistently absent in most PCD patients, regardless of genotype. However, a single patient with a CCDC103 mutation, preserved ciliary function, and normal nasal Nitric Oxide (NO) exhibited normal LR1 and low TBV values. Voluntary cough significantly improved clearance, with a median improvement of 11% (IQR: 4–24%).
Conclusion Absent MC by PRMC should be expected in PCD regardless of genotype but residual ciliary function could result in measurable PRMC. This indicates a potential for PRMC to detect improvement of ciliary function if this can be restored. Addressing involuntary cough and peripheral deposition of radioaerosol is important if PRMC is to be used as outcome measure in future clinical PCD trials.
Footnotes
This manuscript has recently been accepted for publication in the ERJ Open Research. It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of the ERJOR online. Please open or download the PDF to view this article.
Conflicts of interest: June K Marthin, Mathias G Holgersen, Kim G Nielsen and Jann Mortensen have no conflicts of interest to disclose.
Conflicts of interest: The study did not receive any funding.
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- Received September 17, 2023.
- Accepted September 21, 2023.
- Copyright ©The authors 2023
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