Introduction Helium magnetic resonance imaging (3He MRI) provides functional information on lung ventilation, perfusion and microstructure. We describe use of 3He MRI to assess lung function in a patient with “horse-shoe” lung.
Case presentation EB is a 46 year old female with congenital lung abnormalities diagnosed during infancy. Chest x-ray confirmed an abnormal right upper lobe (RUL). Pulmonary arteriography reported hypoplastic RUL vessels. Bronchoscopy confirmed tracheal stenosis, and cardiac catheterisation reported an abnormal pulmonary arterial pattern. A diagnosis of congenital lung anomalies along with asthma was made during her childhood. Throughout her life her condition has been characterised by recurrent severe respiratory tract infections requiring hospitalisation.
Recent CT chest confirmed right lung hypoplasia a deformed right main bronchus, moderate hypoplasia of the right main pulmonary artery and severe hypoplasia of RUL pulmonary vessels. An isthmus joins the two lungs consistent with “horse-shoe lung”.1 Ventilation-perfusion scan reported 26% functioning right lung. Bronchoscopy confirmed tracheal and right main stem stenosis with left main stem bronchomalacia.
Surgical resection is an option for ‘horse-shoe ‘lung characterised by recurrent infections.2 In this context, we proceeded to 3He MRI to obtain more detailed functional information.
Results of 3He Functional MRI Communication between the right and left lungs was visualised (Figure 1). In the right lung, ventilation was reduced with increased heterogeneity (Figure 1a, f). And perfusion notably reduced, in the RUL (Figure 1c. 3He apparent diffusion coefficient (ADC), which estimates acinar airway dimensions, was elevated and heterogeneous (Figure 1c), consistent with hypoplasia. The left lung was well ventilated and perfused with normal ADC values.
Conclusion 3He MRI shows promise in functional analysis of “horse-shoe” lung with hypoplasia. This can prove useful in surgical assessment of these patients and therefore improve their management.
References 1 Dikensoy O, Kervancioglu R, Bayram NG, Elbek O, Uyar M, Ekinci E. Horseshoe lung associated with scimitar syndrome and pleural lipoma. J Thorac Imaging 2006;21(1):73–5
2 Orzan F, Angelini P, Oglietti J, Leachman RD, Cooley DA. Horses lung: report of two cases. Am Heart J 1977;93(4):501–5