T2 Quantifications of Lungs in the Fetal Lamb with Experimentally-Induced Congenital Diaphragmatic Hernia

Abstract

Objective: As an aid to evaluate lung hypoplasia, we investigated the difference between T2 value in fetal lungs of lambs with surgically-induced left-sided diaphragmatic hernia (DH) and gestational age (GA)-matched control littermates (normal [NL]). Methods: Lungs were divided into two groups: DH (n = 4) and NL (n = 6). DH was induced at 65–75 days GA (term = 145 days). Fetal MRI was performed (mean GA: 120 days) with half-Fourier acquisition single-shot turbo spin-echo (TE: 60 ms) and rapid acquisition with relaxation enhancement (TE: 350 ms) in the same location (1.5-T Philips, Gyroscan, Best, The Netherlands). T2 of each lung was calculated for multiple regions of interest by taking natural logarithm of signal-to-noise ratio. Mean T2 was compared between DH and NL (unpaired analysis for entire group). Paired comparison between left/right lung was made within DH and NL. Results: Unpaired analysis showed significantly lower T2 of left respectively right lungs in DH (p = 0.02 [respectively] 0.05]) compared to NL (n = 6), as well as between the T2 of all DH versus NL (p = 0.001). In DH, calculated T2 appeared to be lower in left than in right lungs (difference ranged from –2 to +49%). In NL, left and right lungs showed comparable T2. Conclusion: Measurement of T2 signal intensity in DH lungs is feasible and show lower T2 in comparison to NL lungs. Left lungs from lambs with DH show lower T2 than right lungs.