High temporal versus high spatial resolution in MR quantitative pulmonary perfusion imaging of two-year old children after congenital diaphragmatic hernia repair.

Abstract

Congenital diaphragmatic hernia (CDH) leads to lung hypoplasia. Using dynamic contrast-enhanced (DCE) MR imaging, lung perfusion can be quantified. As MR perfusion values depend on temporal resolution, we compared two protocols to investigate whether ipsilateral lung perfusion is impaired after CDH, whether there are protocol-dependent differences, and which protocol is preferred. DCE-MRI was performed in 36 2-year old children after CDH on a 3T MRI system; protocol A (n = 18) based on a high spatial (3.0s; voxel: 1.25mm(3)) and protocol B (n = 18) on a high temporal resolution (1.5s; voxel: 2mm(3)). Pulmonary blood flow (PBF), pulmonary blood volume (PBV), mean transit time (MTT), and peak-contrast-to-noise-ratio (PCNR)were quantified. PBF was reduced ipsilaterally, with ipsilateral PBF of 45 ± 26ml/100ml/min to contralateral PBF of 63 ± 28ml/100ml/min (p = 0.0016) for protocol A; and for protocol B, side differences were equivalent (ipsilateral PBF = 62 ± 24 vs. contralateral PBF = 85 ± 30ml/100ml/min; p = 0.0034). PCNR was higher for protocol B (30 ± 18 vs. 20 ± 9; p = 0.0294). Protocol B showed higher values of PBF in comparison to protocol A (p always <0.05). Ipsilateral lung perfusion is reduced in 2-year old children following CDH repair. Higher temporal resolution and increased voxel size show a gain in PCNR and lead to higher perfusion values. Protocol B is therefore preferred. • Quantitative lung perfusion parameters depend on temporal and spatial resolution. • Reduction of lung perfusionin CDH can be measured with different MR protocols. • Temporal resolution of 1.5s with spatial resolution of 2mm (3) is suitable.