CAM Study

Background information

Little is known on large airways mechanics in pediatric lung diseases. Bronchoscopy is considered the gold standard modality to assess the large airways and to their mechanics. However, it is an invasive technique that requires general anesthesia. As an alternative, airway dimensions and even mechanics can be measured by CT scan, but this exposes the child to radiation.To overcome this limitation magnetic resonance imaging (MRI) has been developed by our center for the dynamic cine-assessment of the large airways. The diagnostic performance of cine-MRI has never been compared to bronchoscopy. If cine-MRI proves to be as good as bronchoscopy to diagnose large airways diseases, it will be possible to reduce the number of invasive bronchoscopies.

Overall aim

We hypothesize that the new MRI protocol will be sensitive enough to detect changes in large airway dimensions in relation to standardized breathing manoeuvres. To test this hypothesis, the primary objective of this study is to determine sensitivity, specificity, positive predictive value (PPV) and negative predictive value of our MRI protocol compared to flexible bronchoscopy, used as reference test. Secondary aims include: 1) assessing concordance between malacia severity, as determined by MRI and bronchoscopy; 2) relationship between severity assessment of MRI and bronchoscopy with pulmonary function tests and respiratory symptoms; and 3) assessing the influence of bronchodilator in airways mechanics.

Research method

In this cross-sectional study, all study subjects will undergo spirometer controlled MRI within the 3 months prior or after a clinically indicated bronchoscopy. The study will be conducted at Erasmus MC / Sophia Children’s Hospital with study subjects recruited via Sophia Children’s Hospital Pulmonology outpatients’ clinic. The study will involve one visit of approximately 1 hour and 45 minutes. This study will include 60 children, over the age of 6 years from the Sophia Children’s Hospital Pulmonology outpatient clinic for whom a diagnostic bronchoscopy is clinically indicated. 

Desirable outcome

We hope that the new MRI protocol will be as sensitive or even more sensitive than bronchoscopy; sensitive enough to detect abnormal diameter changes (malacia) in relation to standardized breathing manoeuvres.
In addition we hope to study the influence of bronchodilators on the stability of the large airways. If bronchodilators have a negative impact on airways that are more collapsible, these drugs should not be prescribed to for these patients.

Collaborations within Erasmus MC

• Division of Pediatric Pulmonology.
• Department of Pediatrics.
• Department of Radiology.

Tracheomalacia in adults with cystic fibrosis: determination of prevalence and severity with dynamic cine CT. McDermott S, Barry SC, Judge EP, Collins S, de Jong PA, Tiddens HA, McKone EF, Gallagher CC, Dodd JD. (2009). Radiology. 2009 Aug;252(2):577-86.