Test–retest reliability of internal pudendal artery blood flow using color Doppler ultrasound in healthy women

Introduction and hypothesis The internal pudendal artery (IPA) is one of the main arteries supplying the pelvic floor muscles (PFMs) and vulvo-vaginal tissues. Its assessment with color Doppler ultrasound has been documented previously, but the reliability of IPA measurements has never been assessed. This study evaluates the test–retest reliability of IPA blood flow parameters measured by color Doppler ultrasound under two conditions: at rest and after a PFM contraction task. Methods Twenty healthy women participated in this study. One observer performed two measurement sessions using a clinical ultrasound system with a curved-array probe on the participant’s gluteal area. IPA measurements were repeated: at rest and after a PFM contraction task. Peak systolic velocity (PSV), time-averaged maximum velocity (TAMX), end-diastolic velocity (EDV), pulsatility index (PI), and resistance index (RI) were measured. Test–retest reliability was assessed using a paired t test, intraclass correlation coefficient (ICC), and Bland and Altman plots. Results There was no significant difference for all IPA blood flow measurements between the two repeated sessions. At rest, reliability was excellent for PSV and TAMX and the variability between measurements, as per Bland and Altman plots, was small. After PFM contractions, reliability was excellent for PSV and TAMX and fair to good for PI. The variability between measurements was small for PSV and acceptable for TAMX and PI. EDV and RI parameters did not perform as well. Conclusion The assessment of IPA blood flow with color Doppler ultrasound to evaluate vascular change in women is reliable.