Journal of Gynecological Research and Obstetrics 031 5.5 mm sheath (EMD Endoscopy Technologies). Normal saline (0.9% sodium chloride) is used for the distention, at controlled intrauterine pressure of 80-100 Hgmm. A digital camera is connected to the optic, so the results can be objectively evaluated and documented. The examination begins with a routine office hysteroscopy, during which any deformity of the uterine cavity and the endometrium can be visualized. Technique of pertubation In the second step a 1.7 mm plastic catheter (Cavafix, B-Braun) is inserted through the working channel of the sheath and the tip is placed to the tubal ostium (Figures 1,2). During selective pertubation, each Fallopian tube is considered as a diagnostic unit. By rotating the hysteroscope, the direction of the catheter can be modified toward the ostium. The cone shape of the tubal ostium will help in leading the tip of the flexible catheter into the ostium. The catheter should not to be inserted into the tube, only the tip should be placed at the entry of it. Through the catheter 2-10 ml of methylene blue dye (Patente Blue, 2 ml in 1000 ml saline) is injected slowly. In case of a patent Fallopian tube no blue fluid will appear in the uterine cavity. Normal color of the endometrium can be seen, while the transparent catheter turns blue, due to the methylene blue flowing inside it (Figure 3). Occluded Fallopian tube changes the uterine cavity into blue, due to the backflow of the methylene blue (Figure 4). In case of corneal occlusion, blue dye will flow back immediately. If the blockage is at the distal part of the tube, the first fraction of the blue dye will disappear and after some time of the injection will the back-flow be detectable. After the evaluation of tubal patency, blue dye clears up within 5-10 seconds