The Hysteroscopy Encyclopedia

Will hysteroscopy replace HSG in diagnosis of IUA? Since the renewed interest in hysteroscopy, the question has been commonly asked. For a long time hysterography was the only feasible method to visualise the uterine cavity and a high degree of refinement was attained in the interpretation of the hysterogram.( Barbot ,1989)

   

While a normal HSG may be used to exclude Asherman’s syndrome, the conserve is not true. Neither the extent nor the severity of intrauterine adhesions can be established with certainty by hysterography. (March & Israel,1976).
    It is useful to recall that hysteroscopy was established as an examination method many years before hysterography. Thanks to the use of Lipiodol, hysterographies rapidly improved in quality, and this radiographic examination became widely used. Hysteroscopy, however, was much more difficult to perfect for widespread use. Optical instruments, initially larger than todays models, had to be introduced through the narrow and sensitive cervical canal to explore the uterine cavity (Gamerre & Serment, 1983).

    As the efficiency of hysteroscopy was increasingly its confrontation with hysterography gradually showed the weak points of the radiological method. To day, the tendency is to consider hysterography as an outmoded technique that lost its utility( Barbot ,1989).

    In a retrospective study by Fayez et al,1987, four hundred infertile patients had hysterosalpingography and hysteroscopy as part of infertility workup. It was found that hysterosalpingography was as accurate as hysteroscopy in the diagnosis of normal and abnormal uterine cavities while the nature of the intrauterine filling defects was accurately revealed by hysteroscopy only. They concluded that hysterosalpingography is an important screening procedure for the diagnosis of normal or abnormal uterine cavities and that hysteroscopy should be reserved only for the confirmation and treatment of intrauterine abnormalities discovered by hysterosalpingography.

    Evaluation of suspected intrauterine pathology determined by hysteroscopy rather than by hysterography has been advocated because of the improved diagnostic accuracy of hysteroscopy. Several investigators have shown that up to one third of hysterogram may have  false positive findings and that 25% of the cases reported as normal by hysterography demonstrated  a uterine lesion by hysteroscopy ( Dunn, 1994).

    Hysterography is an indirect method, using a contrast medium .What is seen of the uterine cavity on the radiograph is in fact the geometric projection of this cavity on a flat surface (radiographic plate).The aim is  to disclose the contour of the uterine cavity and providing only black and white shadows. HSG provides valuable information only when the procedure is performed with technical perfection. The uterus should be parallel  to the plate to maintain the right proportions in the final image. An accurate mapping of the cavity is obtained witha small enlargement because the film is not in contact with the uterus.
    The image is used to determine the uterine contour, size, and general configuration, small filling defects, congenital malformation, myoma. In addition, it also reveals the anatomy and patency of the tubes.

    On the normal hysterogram the endocervical canal appears as fusiform cavity tapering toward the internal os. The isthmus is a narrow channel with a stricture at each end. The endometrial cavity appears as a triangle with the short base up. The lateral sides of the hysterogram are not straight lines but are made up of two segments forming an angle about half way between the internal os and tubal ostium with the upper segment diverging out. The tubal ostia are often marked by a stricture followed by a dilated triangle corresponding to the initial portion of the tube. (Barbot,1989).

    Barbot ,1989, recorded some technical mistakes that are not uncommon when performing HSG and may be responsible for erronous interpretation:
*The introduction of air bubbles during filling by way of the cannula may cause artifacts suggestive of intrauterine adhesions.
*Failure to apply enough traction on the cervix in order to correct for anteversion or retroversion will not allow adequate exposure of theuterus perpendicularly to the X-rays and results in distortion and foreshorting of the image.
*If there is a filling defect it is difficult to determine its exact location with respect to the anterior or posterior wall of the uterus. Non removal of a radiopaque speculum after fixing the cannula to the cervix will miss meaningful evaluation of the endocervical canal. All of these mistakes can be easily avoided.
*IUA are diagnosed on hysterogram by sharp outlying defects placed at different sites in the uterine cavity which usually persist on sequential film images.
This is an important feature, since a polyp for example, will more or less fade as the filling advances. Adhesions may be central, marginal or may be severe enough to cause blockage to the passage of the dye inside the cavity.

*When synechiae completely obliterate the uterine horn, the remaining portion of the uterine cavity closely simulates a unicornuate uterus. A central synechia located in the middle of the cavity extending to the fundus may cause the uterus to appear as bicornuate on HSG.

*The investigation should be performed during the proliferative phase of the menstrual cycle. Uterine bleeding is a contraindication, since blood clots cause artificial filling defects on the imaging study.

*Routine HSG may demonstrate IUA in about 1.5% of infertile patients, HSG perfromed in patients with habitual abortions show IUA in about 5%.
Klein and Garcia, 1973, demonstrated IUA in 39% of HSG performed on patients with previous puerperal endometrial curettage.

*Hysteroscopy demonstrates not only the location, shape size of the adhesions but also their nature. These can be mucosal, fibrous or myometrial. The endoscopic view also evaluates the status of the remaining endometrium ( i.e. functional or non responsive to hormones). This extrainformation is of great value for the treatment and subsequent prognosis of the disease.

    Gamerre & Serment, 1983, wrote that in the investigation of synechiae, hysteroscopy seems absolutely necessary.Hysteroscopy provides more precise data than hysterosalpingography, as it allows us to choose the most appropriate therapy: a synechia in column  can be excised under operative hysteroscopy but a  marginal one with a firm consistency will be broken down less easily with endoscopy and in that case, these two investigations can provide complementary information. Hysteroscopy is also useful during follow-up after the treatment of uterine malformations or synechiae. While hysterography seems more efficacious in the study of adenomyoma and genital tuberculosis.

    However, long experience with the two techniques and  repeated comparison of the results provided by each of them has shown that each technique has inherent defects and strength, often the two are complementary.( Barbot ,1989)

    In a prospective study of 68 infertile patients, the findings of hysterosalpingography and hysteroscopy have been compared by Romer et al, 1994. Hysterosalpingography showed in 3 cases false-negative results and in 10 cases false positive results. Hysterosalpingography is especially limited in diagnosis of intrauterine adhesions. Hysteroscopy should be a necessary component of diagnosis of sterility, even in cases with normal hysterosalpingographical findings (Romer et al., 1994).



    Munro, 1996, stated that for women with infertility, hysterosalpingography is the best initial imaging step because it provides information about the patency of the oviducts. In the presence of suspicious abnormality in the endometrial cavity, hysteroscopy  can be done to confirm the diagnoses. 
Munro,1996, added that confirmation of patency of the oviduct is unnecessary in women who have recurrent abortions, therefore , can be evaluated primarily with hysteroscopy.

    Finally we can  have this  simple comparison of Hysterography and Hysteroscopy done by March,1992.
Table 5:- Comparison between Hysteroscopy and Hysterosalpingography

 

Parameter	Hysteroscopy	Hysterosalpingography
Method of inspection	direct	indirect
Diagnosis	definitive	presumptive
Localisation of lesion	accurate	vague
Type of procedure	diagnostic & therapeutic	diagnostic
Organ studied	uterus	uterus & tubes
Cost	moderate	low

He considered hysteroscopy the best to detect intrauterine pathology, however, HSG is preferred for those physicians who don’t have office hysteroscopy available. In addition, for infertile patients the additional information about the fallopian tube that can be obtained only by HSG makes this procedure an important one. (March,1992).