Use of diffusion-weighted magnetic resonance imaging to distinguish between normal and small for gestational age pregnancies: comparison of intravoxel incoherent motion derived parameters and apparent diffusion coefficient

OBJECTIVES: We compared the predictive performance of apparent diffusion coefficient (ADC) and intravoxel incoherent motion (IVIM) parameters in assessing small for gestational age (SGA) pregnancies. METHODS: Perspective study. Twenty-eight normal controls and 30 SGA pregnancies underwent IVIM scans on a 3.0 T MRI scanner. The diffusion coefficient (D), pseudodiffusion coefficient (D*), and perfusion fraction (f) were calculated from the IVIM, and the ADC was derived from the IVIM sequence with monoexponential fitting of the IVIM data at b-values of 0 and 800 s/mm. All 4 parameters and AUC within the placenta were compared between normal and SGA pregnancies. RESULTS: All of mean ADC ([1.69 ± 0.19] × 10-3 mm2/s vs [1.42 ± 0.28] × 10-3 mm2/s), D (1901.08 ± 199.77 µm2/s vs 1635.17 ± 244.18 µm2/s), D* (56 445.78 ± 8125.91 µm2/s vs 47 600.62 ± 7642.15 µm2/s), and f (33.35% ± 3.36% vs 27.30 ± 3.48%) were significantly decreased in SGA pregnancies (P < .001 for all). The diagnostic performance of f (AUC = 0.896; sensitivity, 80.00%; specificity, 92.86%; cut-off value, 29.28%) was significantly better than ADC (AUC = 0.788; sensitivity, 86.67%; specificity, 70.83%; cut-off value, 1.63 × 10-3 mm2/s; P = .035), D (AUC = 0.798; sensitivity, 70.00%; specificity, 82.14%; cut-off value, 1708.17 µm2/s; P = .041), and D* (AUC = 0.800; sensitivity, 63.33%; specificity, 89.29%; cut-off value, 48181.97 µm2/s; P = .044). CONCLUSIONS: Our study suggested that f, a perfusion parameter derived from IVIM, was a more powerful independent predictor than ADC and other IVIM parameters of SGA pregnancies. ADVANCES IN KNOWLEDGE: This study compared the ADC and IVIM in diagnosing SGA.