Pulmonary ventilation and micro-structural findings in congenital diaphragmatic hernia

With increasing survival of patients with more severe forms of congenital diaphragmatic hernia (CDH) and risk of long-term respiratory morbidity, studies on lung morphology are needed. We used hyperpolarised (3) He MRI and anatomical (1) H MRI in a cohort of young adult CDH patients to image regional lung ventilation and microstructure, focusing on morphological and micro-structural (alveolar) abnormalities.

Nine patients with left-sided CDH, born 1975-1993, were studied. Regional ventilation was imaged with hyperpolarised (3) He MRI, and the (3) He apparent diffusion coefficient (ADC) was computed separately for the ipsilateral and contralateral lungs. (1) H MRI was used to image lung anatomy, total lung volume and motion during free-breathing.

(3) He MRI showed ventilation abnormalities in six patients, ranging from a single ipsilateral ventilation defect (3 patients) to multiple ventilation defects in both lungs (one patient treated with extra corporeal membrane oxygenation). In eight patients, (3) He ADC values for the ipsilateral lung were significantly higher than those for the contralateral lung.

Functional and micro-structural changes persist into adulthood in most CDH patients. Ipsilateral elevated (3) He ADC values are consistent with enlargement of mean dimensions of the confining lung micro-structure at the alveolar level.