Definitive diagnosis and location of peanuts in the airways using magnetic resonance imaging techniques.

A 14-month-old boy suspected to have aspirated peanut fragments into the airways was transferred to our hospital. His chest radiographs revealed Holzknecht's sign, which indicated left mainstem bronchial obstruction. Magnetic resonance imaging with T1-weighted images clearly showed a high-intensity signal of peanut fragments in the left mainstem bronchus. Removal was performed by bronchoscopy in a shorter time under general anesthesia. Magnetic resonance imaging with T1-weighted images (T1WI) is useful for definitive diagnosis and location of peanut fragments in the lower airway because the peanut material appears as a high-intensity signal surrounded by the low-intensity lung tissue. Various slice orientations of T1WI provide accurate information concerning anatomic location of such fragments, thus facilitating removal by bronchoscopy.