HSG- blocked tube analysis

FYI for anyone having an HSG that shows 1 or 2 blocked tubes. I found a study/analysis that might give some insight into reasons it might not be a true blockage:

       If an HSG procedure shows blockage of one tube and patency of the other,

there could simply be a resistance difference between the two tubes, resulting in the contrast following the path of least resistance and thus falsely suggesting that the tube with greater resistance is blocked.12 Another scenario resulting in false-positive diagnosis of tubal occlusion is when inadequate wedging of cervical cannula allows leakage of contrast material into the vagina, thus interfering with generation of sufficient intracavitary pressure and often leading to a misdiagnosis of tubal occlusion.19 In these situations, it would be of great benefit to proceed with a selective salpingogram and clearance of the apparently blocked tube, as that would result in correct diagnosis of the patient.12, 19 It is also important to be aware of the fact that tubal spasm may mimic tubal occlusion and result in false-positive diagnosis of tubal occlusion.2 In order to minimize such diagnostic errors, use of smooth muscle relaxants for the relief of tubal spasms has been suggested.26 In addition, concluding the study prematurely, failing to obtain delayed or follow-up films as well as to use adequate amounts of contrast material can lead to a false diagnosis of proximal tubal obstruction. If an apparent unilateral blockage is visualized, one should continue to add 1-2 ml of contrast material until either the material from the patent side appears to obscure the pelvic shadow or the opposite tube fills and spills.20  Several authors have shown the importance of consistency in injection pressure and spot film timing in carrying out HSG procedures. Differences in both of these aspects have been shown to have a great effect on visualization of anatomic contours as well as the assessment of tubal patency and filling.9,19