The aim of the study is to compare the concordance between chest computerized tomography-scan (CTscan) and Magnetic resonance Imaging (MRI) for the description of the abnormalities seen in Allergic BronchoPulmonary Aspergillosis (ABPA).

The ABPA is responsible for pulmonary exacerbations in chronic bronchial diseases. The treatment of ABPA consists in systemic corticosteroids and anti fungal therapy, which can have severe side effects. The diagnosis is difficult, based on several but non-specific characteristics. One of the radiologic abnormalities on CTscan could be more specific : high attenuation in impacted mucus, but this sign is found in about 30% of cases. Recent articles and investigators experience seem to demonstrate that MRI could provide an interesting tool for ABPA diagnosis, studying the signal of bronchial impactions. The aim of the study is to describe the MRI characteristics of patients with ABPA and compare the results with those obtained by CTscan, and in order to determine if there is a specific signal of impaction in ABPA.

Inclusion Criteria:

• study patients have a diagnosis of ABPA
• control patients have severe asthma
• All the patients are ≥ 18 years old, have social security care, signature of consent form

Exclusion Criteria:

• cystic fibrosis
• other type of aspergilloses
• contraindication for MRI
• woman without effective contraception