Microscopic magnetic resonance imaging of the thoracic venous system in rats with congenital diaphragmatic hernia.

BACKGROUND/AIM: Infants and rats with congenital diaphragmatic hernia (CDH) have malformations of the heart and the great arteries caused by neural crest (NC) dysregulation during embryogenesis. Abnormally narrow jugular veins have been found in babies during cannulation for ECMO. However, the venous system has not been examined in depth so far. We hypothesized that abnormal patterning and/or size of the thoracic veins could occur in rats with CDH. This hypothesis was tested by microscopic magnetic resonance imaging (MMRI), a high-resolution tool able to detect subtle changes of vessels in small animals.

MATERIAL/

METHODS

Fetuses from pregnant rats fed either 100 mg i.g. nitrofen or vehicle on E9.5 were recovered near term. A 7 T MMRI system with a coronal multislice fast spin echo sequence allowed diagnosis of CDH (n = 19), and T2 SE high-resolution sequences made assessment of the pattern and width of cervico-thoracic veins possible. Values were corrected for body size by dividing them by the length of thoracic vertebrae T3-T5. The results in nitrofen and control (n = 11) groups were compared by non-parametric tests (*p < 0.05).

RESULTS

Congenital diaphragmatic hernia fetuses were smaller than controls (4.5 ± 0.26 vs. 5.3 ± 0.2 g*). The widths (corrected for body size) of left external, both innominate, right superior vena cava and azygos veins were significantly smaller in CDH rats than in controls.

CONCLUSIONS

The cervico-thoracic veins are normally patterned but abnormally narrow (except the internal jugulars) in rats with CDH. The same embryonic NC dysregulation that accounts for cardiovascular malformations could also explain these venous anomalies in CDH.