LAUSR

STUDY OBJECTIVE To compare preoperative transvaginal ultrasound (TVUS) and magnetic resonance imaging (MRI) with intraoperative ultrasound (IOUS) in surgeons first learning to use this technique. DESIGN A prospective study of IOUS accuracy for mapping the size and location of myomas compared with TVUS or MRI (Canadian Task Force classification II-2). SETTING Five University of California academic centers (Davis, Irvine, Los Angeles, San Diego, and San Francisco). PATIENTS Twenty-six premenopausal women seeking uterine-sparing surgical treatment of myomas. Eligible participants could have no more than 6 myomas ≥2 cm and <10 cm and a uterine size no larger than 16 weeks by pelvic examination. INTERVENTIONS Measurement of myomas by IOUS followed by radiofrequency ablation (RFA) of fibroids. MEASUREMENTS AND MAIN RESULTS Eligible participants had to have imaging with TVUS or MRI within the last year to assess myoma characteristics. During the RFA operation, surgeons who had undergone a 1-day training on RFA and IOUS measured all myomas visualized with IOUS. Surgeons measured more myomas than were reported on MRI (12 on MRI and 16 on IOUS) or TVUS (41 on TVUS and 62 on IOUS) in all positions (anterior, posterior, lateral, and fundal). In particular, they identified more myomas <2 cm (4 on MRI, 9 on IOUS, 1 on TVUS, and 19 on IOUS). They located 2.3 times as many myomas in the anterior position as TVUS. For the myomas ≥2 cm identified by IOUS and MRI or IOUS and TVUS, there was no statistically significant difference in the mean myoma number or the mean myoma diameter measurements. CONCLUSION Surgeons first learning to use IOUS detect the same number of myomas ≥2 cm as identified by TVUS and MRI and find a greater number of myomas <2 cm on IOUS compared with radiologist-reported TVUS.