Geburtshilfe Frauenheilkd 2011; 71 - V_2
DOI: 10.1055/s-0031-1286493

Angle of progression measurements of fetal head at term: a systematic comparison between open magnetic resonance imaging and transperineal ultrasound

C Bamberg 1, S Scheuermann 1, C Fotopoulou 2, T Slowinski 3, A Dückelmann 1, U Teichgräber 4, F Streitparth 4, W Henrich 1, JW Dudenhausen 1, KD Kalache 1
  • 1Department of Obstetrics
  • 2Department of Gynecology
  • 3Department of Nephrology
  • 4Department of Radiology – Charité University Hospital, Berlin, Germany

Objectives:

During labor, transperineal sonography is increasingly used to evaluate fetal head descent. The aim of the present study was to compare the angle of progression assessed by open magnetic resonance imaging (MRI) versus transperineal ultrasound.

Methods:

31 pregnant women at term (>37 weeks), who were not in labor, underwent a MRI in an open 1.0 Tesla system. A midsagittal plane of the maternal pelvis was stored. Immediately after, without changing the supine position, a transperineal ultrasound was performed. The angle of progression was measured off-line by transperineal ultrasound and MRI.

Results

The angles of progression measured by transperineal ultrasound (mean 79.05°, SD 11.44) and MRI (mean 80.48°, SD 11.06) correlated significantly (p<0.001). The intraclass correlation coefficient between the two methods was 0.89 (95% CI: 0.78–0.94).

Conclusion:

The angle of progression measurements obtained by transperineal ultrasound and open MRI showed very good agreement. This ultrasound technique provides reliable reproducible information of the fetal head station and it can become a ueful easy bed side tool to help in the clinical decision making of a trial of instrumental delivery versus a C-section at full dilatation