Quantitative Flow Measurements of Pelvic Venous Vasculature Using 4D Flow MRI.

To evaluate 4D Flow magnetic resonance imaging (MRI) sequences for quantitative flow measurements of the pelvic venous vasculature. A prospective study of healthy volunteers was performed. After informed consent all subjects underwent 4D flow sequences at a 3 T MRI scanner with different isotropic resolution and different velocity encoding (Venc) settings: (sequence #1) voxel size (VS) 1.6³ mm³, Venc 50 cm/s; (sequence #2) VS 1.6³ mm³, Venc 100 cm/s and (sequence #3) VS 2.0³ mm³, Venc 50 cm/s. Perfusion parameters were calculated for all venous vessel segments starting at the level of the inferior vena cava and extending caudally to the level of the common femoral vein. For reference, arterial flow was calculated using 1.6³ mm³ isotropic resolution with a Venc of 100 cm/s. Ten healthy subjects (median age 28 years, interquartile range [IQR]: 26.25–28 years) were enrolled in this study. Median scanning time was 12:12 minutes (IQR 10:22–13:32 minutes) for sequence #1, 11:02 minutes (IQR 9:57–11:19 minutes) for sequence #2 and 6:10 minutes (IQR 5:44–6:47 minutes) for sequence #3. Flow measurements were derived from all sequences. The venous pelvic vasculature showed similar perfusion parameters compared to its arterial counterpart, for example the right common iliac arterial segment showed a perfusion of 8.32 ml/s (IQR: 6.94–10.68 ml/s) versus 7.29 ml/s (IQR: 4.70–8.90 ml/s) in the corresponding venous segment (P = 0.218). The venous flow measurements obtained from the three investigated sequences did not reveal significant differences. 4D Flow MRI is suitable for quantitative flow measurement of the venous pelvic vasculature. To reduce the scanning time without compromising quantitative results, the resolution can be decreased while increasing the Venc. This technique may be utilized in the future for the diagnosis and treatment response assessment of iliac vein compression syndromes. [ABSTRACT FROM AUTHOR]