Ultrasound Obstet Gynecol 2007; 29: 717–719 Published online in Wiley InterScience (www.interscience.wiley.com). Correspondence Sonohysterography in the preoperative grading of submucous myomas: considerations on three-dimensional methodology Lee et al. 1 report good intra- and interobserver repro- ducibility of three-dimensional (3D) saline contrast sono- hysterography (SCSH) in the preoperative grading of submucous myomas. This is good news, as presurgical sonohysterographic assessment of submucous myomas simplifies the diagnostic triage of women with this lesion. However, no method for the reproducible 3D assessment of submucous myomas with intramural extension (G1, G2) – for which accuracy is lower than that for intracavi- tary myomas (G0) 2 – was given. We tried to define strict criteria in our recent study, which used traditional mono- planar transvaginal sonohysterographic assessment 3 . We believe that a 3D technique could simplify this methodo- logy when step-by-step processing of the acquired volume is performed as follows: 1. Start with the multiplanar display mode; 2. Identify and magnify the selected image of the fibroid: use longitudinal sections of the uterus if the myoma is anterior, posterior or fundal, transverse sections if the myoma is lateral, and coronal sections if the myoma is periostial; 3. Shift the selected plane forwards and backwards until the plane containing the largest diameter of the submucous myoma protruding into the cavity is identified; 4. Rotate the fibroid on its ideal center (‘fulcrum’) on the z-axis until the line passing through the center of the myoma and the perimetrial point (where the myometrium is thinner) becomes coincident with the y-axis (Figure 1). This axis must be perpendicular to the plane tangential to the perimetrium (x-plane); 5. Carry out fine rotations and shifts to improve the identification of the best plane possibile as defined in Steps 3 and 4. If all these steps are performed correctly, complete rotation of the myoma on the y-axis should not change the relationship between the intramural and intracav- itary portions of the myoma. The line joining the two myoma – endomyometrial junctions should divide the myoma into the two portions on which grading is based (intramural/intracavitary ratio; Figure 1). The myometrial free margin (the thickness of myometrium within the deep- est intramural portion of the submucous myoma and the perimetrium) can be easily evaluated on this image. In addition to these considerations, accuracy in grading by SCSH is also largely determined by the intrauter- ine pressure achieved at sonohysterography and hys- teroscopy. In the paper by Salim et al. 2 , to which Lee y z x Figure 1 Three-dimensional processing for grading of submucous myomas. Rotation on the y-axis (planes outlined by gray dashed lines) does not modify the intramural/intracavitary ratio. et al. refer for their methodology, we observed that intrauterine pressures on hysteroscopy were much higher (100 – 120 mmHg) than those generated by gentle instilla- tion of 5 – 10 mL sterile saline on sonohysterography. This difference in intrauterine pressure renders the two diag- nostic techniques incomparable. Not only would the high pressures used for hysteroscopy cause unbearable pain at SCSH but they may have a noticeably different effect on protrusion of myomas into the cavity which could partly explain the lower accuracy observed for submucous myomas with intramural extension (G1–G2) in Salim et al.’s study. We suggest that SCSH and hysteroscopy should be compared at similar intrauterine pressures and one that never exceeds 50 mmHg, as in our study. F. P. G. Leone*, T. Bignardi, C. Marciante and E. Ferrazzi Department of Obstetrics and Gynaecology, Clinical Sciences Institute L. Sacco, University of Milan, Via G.B.Grassi 74, 20157 Milan, Italy *Correspondence. (e-mail: f.leone@hsacco.it) DOI: 10.1002/uog.4043 References 1. Lee C, Salim R, Ofili-Yebovi D, Yazbek J, Davies A, Jurkovic D. Reproducibility of the measurement of submucous fibroid Copyright  2007 ISUOG. Published by John Wiley & Sons, Ltd. CORRESPONDENCE