HyCoSy technique
Indications
Evaluation for tubal patency
1. in infertile patients
2. in patients who undergo previous tubal surgery (ectopic pregnancy, endometriosis, adhesiolysis)
Evaluation of tubal occlusion:
1. in women who undergo permanent hysteroscopic tubal sterilization to confirm tubal occlusion
2. in women with hydrosalpinx eligible for IVF, to confirm tubal occlusion after hysteroscopic tubal device insertion
Exclusion criteria:
1. Pregnancy ongoing
2. Reproductive tract cancer
3. History of pelvic infection
4. Currently vaginal infections (especially Chlamydia)
5. Patients with tubal pathology, detectable by ultrasound (hydrosalpinx, acute salpingitis)
6. Patients with risks factors (heart disease, especially heart shunt hypertension, ictus etc.)
7. Vaginal bleeding
Preparation prior to HyCoSy:
Infertile patients should be during the proliferative phase of the cycle (day 5–12)
Couples should also be advised to avoid intercourse or to use contraception prior
A negative pregnancy test offers insufficient reassurance
The procedure should be delayed if there is any possibility that the patient may be pregnant.
Screen for vaginal infections at least for Chlamydia
Before the procedure written consensus should be signed by the patients and complications explained
Complications of HyCoSy:
Infection
Pain
Vasovagal episode
Intravasation
Contrast medium allergic reaction
Vaginal bleeding
Exclusion criteria as for HSG are: ongoing pregnancy reproductive tract cancer, pelvic and vaginal infections, presence of tubal pathology, detectable by ultrasound (hydrosalpinx, acute salpingitis), vaginal bleeding, presence of risks factors such as heart disease, especially heart shunt hypertension, ictus, etc. Prior to the procedure, an ultrasound of the uterus for myomas and adenomyosis and of the ovaries for cysts can also be performed, allowing for a complete evaluation of the pelvis.
HyCoSy is performed better and safer during the proliferative phase of the cycle (day 5–12). In order to perform these procedures in other phases of the cycle, couples should also be advised to avoid intercourse or to use barrier methods of contraception prior to the exam. A negative pregnancy test offers insufficient reassurance, and the procedure should be delayed if there is any possibility that the patient may be pregnant.
HyCoSy is an aseptic rather than a sterile procedure; however, all staff involved must observe strict aseptic technique and all equipment used must be sterile for single use only. The introitus is cleaned (with 0.1 % chlorhexidine) and a well-lubricated speculum introduced gently into the vagina. The cervical canal is cannulated by a balloon catheter (Fig. 8.1). The balloon is inflated and can be placed in the cervical canal or in the uterine cavity possible at the level of the internal cervical os (Fig. 8.2). This step ensures that the cervical canal is closed, thus preventing leakage of fluid in the vagina and keeping the catheter in the correct position. The most frequently used catheters are the 5 F catheter with a 2 cc balloon catheter (Fig. 8.1); however, also other type of catheter without balloon but with other form that occlude the uterine cervical os has been proposed. The contrast medium is infused slowly and gently by hand injection into the uterine cavity under sonographic control. It is crucial to infuse the contrast slowly in order to minimize discomfort. Forcible or rapid infusion causes significant pain, which in turn may limit the investigation and cause tubal spasm.
Fig. 8.1
(a–d) Procedures for the insertion of the balloon catheter
Fig. 8.2
Visualization of the balloon catheter in the uterus (a) balloon (white arrow) in the cervical canal, (b) balloon the uterine cavity at the isthmic level occluding the internal cervical os, (c) balloon the uterine cavity
During the intrauterine injection of contrast fluid is visualized by TVS, the contrast media first is seen in the uterus as hyperechoic fluid due to the air bubbles (Fig. 8.3), then with small movements of the probe it is seen in the intramural part of tube and it is followed again by moving the tip of the probe in the intrapelvic part of the tube. Being the tube on different scanning plan, the research of the plane where the hyperechoic fluid in the tube is seen could be sometimes difficult especially in cases where the tube is tortuous or showed an acute angle (Fig. 8.4). If the tube is patent, the hyperechoic contrast medium is seen in the intramural part of the tube, then in the distal part, and then it spills into the abdominal cavity. Tubal occlusion was assessed when the contrast media remains concentrated only in the uterus or in the tube and when it does not spill in the abdominal cavity. The process of scanning and searching for salpinges during injection should be methodical and constant. It seems reasonable to start at the uterine cornua in a plane that also visualize the interstitial part of the tubes and then scan laterally. Finally the contrast media can be detected around the ovaries (Fig. 8.5). Salpinges are examined separately at 2D HyCoSy.
Fig. 8.3
Visualization of hyperechoic contrast medium (saline and air) in the uterus and in the tube (arrows), note the overlapping of similar hyperechoic signals coming from the surrounding tissues especially from air in the bowel
Fig. 8.4
Ultrasound image from tubes filled by hyperechoic contrast medium (gel foam) in the tube (arrows), (a, b) two different cases of tortuous tubes, (c) tube with an acute angle
Fig. 8.5
Visualization of hyperechoic contrast medium (gel foam) in the uterine cavity, in the tube (white arrows), and then it spills into the abdominal cavity around the ovary (yellow arrows)
Generally the solution is injected slowly and with a constant pressure, higher pressure can be applied if the tubes seem to be occluded. If the procedure became intolerable or at patient request the examination is interrupted for a short period to allow tubal spasm to pass.
8.3 Contrast Media for HyCoSy
Different contrast media can be injected through the catheter and visualized going through the cornua, traversing the fallopian tube, surrounding the ovaries, and then spilling into the peritoneal cavity. It was found that to evaluate fallopian tubes by HyCoSy a sonographic enhancing positive-contrast medium might be used. These positive-contrast agents outline the fallopian tubes, giving a hyperechoic appearance (Figs. 8.4 and 8.5). The most simple and inexpensive contrast medium used is saline solution mixed with air. When this solution is shaken, it generates a suspension of air bubbles that are easily identified sonographically when injected into the uterine cavity and the fallopian tubes
Tubal patency is observed by visualizing the hyperechoic air bubbles traversing the tubal course and surrounding the ovary and then spilling into the peritoneal cavity.
HyCoSy with saline and air is a very accurate and feasible method to evaluate tubal status [2]: several authors [3, 4] showed a similar concordance rate (80–90 %) between HSG and dye test and HyCoSy and dye test, showing that HyCoSy and HSG are equally effective in diagnosing tubal patency
Accuracy of HyCoSy has been shown to be comparable to HSG when compared to laparoscopic dye test, sensitivity ranges from 75 to 96 % and specificity ranges from 67 to 100 % [2, 4, 5]. The role of HyCoSy as the initial screening of infertile patients has been established being the positive predictive value of this screening method of 85–95 % when compared to laparoscopic chromo perturbation
The main limits of HyCoSy with air and saline result in highly observer-dependent technique, and it is only accurate in the hands of experienced investigators because fallopian tubal course is not linear and lies on different planes so rapid movements of the probe are needed in order to visualize the fluid passage in the entire tube during infusion time; it is not so accurate on occluded tubes, possibly due to the difficulties distinguishing saline and air in the tubes from air moving in the bowels; finally it does not provide an image of the entire tube and its course, as HSG does.
This led to the model of HyCoSy where the entire course of the tube is visualized using ultrasound dedicated ultrasound contrast media. These media improved operator feasibility by allowing for longer and easier visualization of the contrast medium in the tube. These ultrasound dedicated contrast media are safe and FDA and CE approved for intravenous use, but not indicated for intrauterine use. Therefore their use, despite no adverse effects during HyCoSy have been registered, is off label.
In 2007 a nonembryo-toxic gel (ExEm-gel®; GynaecologIQ, Delft, The Netherlands), containing hydroxyethylcellulose and glycerol, was introduced and registered for the dilatation of the uterine cavity during sonography, being an intrauterine medium for sonohysterography as an alternative to saline [13]. When this gel is diluted and pushed rigorously through small openings in syringes or tubes, turbulence will cause local pressure decrease resulting in air dissolving in the solution, thus yielding foam that is stable for several minutes. This ExEm foam is now registered and CE approved for tubal patency evaluation [6, 7]. The visualization of contrast passage in the tubes is really improved with this hyperechoic positive ExEm foam, increasing HyCoSy diagnostic accuracy. However, some limits are still encountered concerning the requirement of an experienced sonographer able to quickly manipulate the TVS probe during the fluid injection in order to visualize the entire tubal course. Because sometimes there is tubal spasm, partial obstructions or overlapping ultrasound images of other organs, (i.e. bowel, ovaries, etc.), it is not always possible to visualize the entire tube also with this hyperechoic positive-contrast media. The false positive rate for tubal occlusion remains 5–10 %. These results may indicate that HyCoSy can identify tubal patency more easily than obstruction. This could be explained by temporary tubal occlusion caused by spasm that can lead to a false diagnosis by HSG, whereas tubal patency can be recognized during HyCoSy by reinjection the solution after some minutes when tubal spasm has passed. One of the main advantages of HyCoSy over HSG seems therefore to be that it allows continuous, repeatable, and direct real-time examination of the fallopian tubes. However, it requires a well-trained sonographer with experience in the procedure. Learning to differentiate between a real occlusion and a temporary spasm requires patience and experience.
8.4 Other Ultrasound Technologies for HyCoSy
To overcome all the problems of conventional 2D HyCoSy, with different contrast media and ultrasound techniques, two ultrasound technologies have been proposed to improve HyCoSy feasibility [8–10]: the first to better visualize the signals coming from the contrast medium and the second, three dimensional (3D) sonography, to acquire a volume of the fallopian tubes [11–13].
The first technology emits an ultrasound beam at a selected frequency and receives a narrow band of harmonic signal, avoiding the overlapping between the tissue and the contrast response. These technologies, by means of low acoustic pressure, allow the detection of the contrast media by selecting the harmonic response of the microbubbles of the contrast medium from the signals coming from insonated organs. Excluding the fundamental image, the US contrast media can be easily identified without interference from other pelvic organs (Fig. 8.6). Coded contrast imaging (CCI) (GE Healthcare, Zipf, Austria) is one of the technical solutions for the optimization of the use of ultrasound contrast media by means of low acoustic pressure.
Fig. 8.6
Visualization with 2D coded contrast imaging (CCI) of hyperechoic contrast medium (gel foam) in the tubes. Note only the harmonic response from the signals coming from the contrast medium excluding the fundamental waves and obtaining an image without appearance from other pelvic organs. (a, b) two different cases where the uterus is seen in center as hypoechoic image and the contrast media in both tubes can be easily identified (white arrows)
Furthermore, 3D ultrasound technologies were combined to CCI, detecting on the volume and on the multiplanar view only the signals coming from the contrast medium in the uterus and in the tubes 3D TVS permits to acquire volume of the uterus and tubes during injection of the contrast media. 3D HyCoSy volume is seen first as in multiplanar view of the uterus and tubes showing these organs on different plane, especially on the coronal section (Figs. 8.7, 8.8, 8.9, and 8.10). The possibility to rotate this volume more accurately shows the tubal course in space (Fig. 8.11).
