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.