Semi-Quantitative Assessment Of Localized Pulmonary Inflammation By Magnetic Resonance Imaging In Patients With Mild Allergic Asthma Following Segmental Allergen Challenge

Segmental challenge with allergen or endotoxin is a powerful tool to study mechanisms of airway inflammation and to test for efficacy of anti-inflammatory compounds. The assessment of airway inflammation by bronchoalveolar lavage (BAL) requires a bronchoscopy. Moreover, repetitive procedures to study inflammation over time are not possible. Noninvasive assessment of airway inflammation by magnetic resonance imaging (MRI) might add to the diagnostic armamentarium and might allow for sequential assessment of inflammation. 11 Patients with mild intermittent allergic asthma with positive responses to inhaled allergen (either grass mix or house dust mite) underwent segmental allergen challenges. After a baseline (B) BAL, four segments were instilled with either saline (S: right upper lobe), a low dose of allergen (LA: medial segment of the right middle lobe), or a high dose of allergen in two segments of contralateral lungs (HA: lateral segment of the right middle lobe and a lingular segment). MRI at 1.5T (Avanto, Siemens, Germany) was acquired 6 hours and 24 hours after segmental challenge using different sequences (TrueFISP, VIBE, T2HASTE, and T2-TIRM). Introduction