Efficacy of model-based iterative reconstruction in cystic fibrosis assessment using CT

Feasibility of dynamic chest radiography to calculate lung volumes in adult people with cystic fibrosis: a pilot study

INTRODUCTION

Dynamic chest radiography (DCR) is a novel, low-dose, real-time digital imaging system where software identifies moving thoracic structures and can automatically calculate lung areas. In an observational, prospective, non-controlled, single-centre pilot study, we compared it with whole-body plethysmography (WBP) in the measurement of lung volume subdivisions in people with cystic fibrosis (pwCF).

METHODS

Lung volume subdivisions were estimated by DCR using projected lung area (PLA) during deep inspiration, tidal breathing and full expiration, and compared with same-day WBP in 20 adult pwCF attending routine review. Linear regression models to predict lung volumes from PLA were developed.

RESULTS

Total lung area (PLA at maximum inspiration) correlated with total lung capacity (TLC) (r=0.78, p<0.001), functional residual lung area with functional residual capacity (FRC) (r=0.91, p<0.001), residual lung area with residual volume (RV) (r=0.82, p=0.001) and inspiratory lung area with inspiratory capacity (r=0.72, p=0.001). Despite the small sample size, accurate models were developed for predicting TLC, RV and FRC.

CONCLUSION

DCR is a promising new technology that can be used to estimate lung volume subdivisions. Plausible correlations between plethysmographic lung volumes and DCR lung areas were identified. Further studies are needed to build on this exploratory work in both pwCF and individuals without CF.

TRIAL REGISTRATION NUMBER

ISRCTN64994816.

Best Practices: Imaging Strategies for Reduced-Dose Chest CT in the Management of Cystic Fibrosis-Related Lung Disease

OBJECTIVE. Cystic fibrosis (CF) is a multisystemic life-limiting disorder. The leading cause of morbidity in CF is chronic pulmonary disease. Chest CT is the reference standard for detection of bronchiectasis. Cumulative ionizing radiation limits the use of CT, particularly as treatments improve and life expectancy increases. The purpose of this article is to summarize the evidence on low-dose chest CT and its effect on image quality to determine best practices for imaging in CF. CONCLUSION. Low-dose chest CT is technically feasible, reduces dose, and renders satisfactory image quality. There are few comparison studies of low-dose chest CT and standard chest CT in CF; however, evidence suggests equivalent diagnostic capability. Low-dose chest CT with iterative reconstructive algorithms appears superior to chest radiography and equivalent to standard CT and has potential for early detection of bronchiectasis and infective exacerbations, because clinically significant abnormalities can develop in patients who do not have symptoms. Infection and inflammation remain the primary causes of morbidity requiring early intervention. Research gaps include the benefits of replacing chest radiography with low-dose chest CT in terms of improved diagnostic yield, clinical decision making, and patient outcomes. Longitudinal clinical studies comparing CT with MRI for the monitoring of CF lung disease may better establish the complementary strengths of these imaging modalities.