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

[congenital diaphragmatic hernia]

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 3 T MRI system ; protocol A (n = 18 ) based on a high spatial (3 .0 s ; voxel : 1 .25 mm (3 )) and protocol B (n = 18 ) on a high temporal resolution (1 .5 s ; voxel : 2 mm (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 ± 26 ml /100 ml /min to contralateral PBF of 63 ± 28 ml /100 ml /min (p = 0 .0016 ) for protocol A ; and for protocol B , side differences were equivalent (ipsilateral PBF = 62 ± 24 vs . contralateral PBF = 85 ± 30 ml /100 ml /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 perfusion in CDH can be measured with different MR protocols . • Temporal resolution of 1 .5 s with spatial resolution of 2 mm (3 ) is suitable .