Lung MRI and Allergic Broncho-pulmonary Aspergillosis in Cystic Fibrosis

Diagnostic Accuracy of Lung MRI to Detect Allergic Broncho-pulmonary Aspergillosis in Cystic Fibrosis

In this diagnostic study, the aim is at evaluating the diagnostic accuracy of MRI (Magnetic Resonance Imaging) to detect allergic broncho-pulmonary aspergillosis in patients with cystic fibrosis.

Allergic broncho-pulmonary aspergillosis (ABPA) is not rare in the context of cystic fibrosis (CF), with a prevalence reported between 2% to 16%. This complication is a diagnostic challenge for clinicians, since it is related with poorer outcome and higher worsening of the disease. Therefore, the treatment relies on corticosteroid and antifungal therapy and thus, it is important to detect with good sensitivity because CF patients are usually treated with antibiotics. However, the treatment is often difficult to be initiated because of potential secondary side effects related to diabetes mellitus, growth impairment, bone mineralisation or immunodepression. Therefore, there is a need for specific diagnostic tool to discriminate ABPA amongst other polymicrobial infection.

Lung MRI is a radiation-free imaging modality which offers the potential to combine several contrasts, in order to enable in vivo tissue characterization non-invasively. Investigators hypothesize that characterization of mucoid impaction using lung MR T1-weighted and T2-weighted contrasts may be a specific tool to diagnose ABPA in CF non invasively. Additional information on functional information related to ventilation and/or perfusion will be assessed using functional MR sequences, to assess the severity of small airway impairment. Moreover, the diagnostic value of structural alterations such as bronchiectasis, mucoid impaction and consolidation/atelectasis using either MRI with ultrashort echo times or CT using reduction of doses down to chest radiograph levels will be assessed.

Inclusion Criteria:

• Cystic fibrosis proven by sweat chloride and genetic tests
• Age superior or equal to 6 year-old
• Diagnosis of ABPA available on the basis of the criteria by Cystic Fibrosis Foundation Consensus Conference
• No contraindication to perform MRI

Non-Inclusion Criteria:

. Age inferior to 6-year-old

• Cystic fibrosis not proven
• ABPA status not documented
• MRI contraindications: Pregancy, Magnetically activated implanted devices (cardiac pacemakers, insulin pumps, neurostimulators, cochlear implants...), metal inside the eye or the brain (aneurysm clip, ocular foreign body not compatible with MRI), cardiac valvular prothesis not compatible with MRI, subject with claustrophobia.

Exclusion Criteria: None