Fertility ultrasound scan examinations
 
As for general gynaecology transvaginal scanning improved infertility screening and reduced the need for more invasive tests. It has been used in different ways to improve patients' management within the field of Reproductive Medicine.
 
Basic scan
 
Infertility investigations would not be complete without a basic transvaginal ultrasound scan examination. Though each scan is a snap shot at the time of examination it gives important information regarding certain problems which could interfere with fertility chances. It is important to exclude such conditions as
  • Fibroids location and size
  • Endometrial polyps
  • Ovarian cysts
  • Tubal dilatation
  • Signs of intrauterine adhesions
  • Signs of pelvic adhesions including dislocated ovaries, encysted fluid in the pelvis, dilated tubes and restricted pelvic organs movement in relation to each other during examination [negative organ sliding test]
  • Locolisation of site specific tenderness during examination in cases of chronic pelvic pain assessment.
  

Two large hydrosalpinges stuck behind the uterus

It is important to remember that HSG could give false results with tubal patency. A large hydrosalpinx could allow spread of the dye into the dilated distal part of the tube simulating proper smearing as seen with normal tubes. I have seen this problem in few occasions when HSG reports document patent tubes where as transvaginal scanning confirmed the presence of large hydrosalpinges. Unfortunately most clinicians not personally involved in scanning their own patients tend to follow the result of the HSG.   

It is very easy to diagnose a hydrosalpinx with transvaginal scanning using 3 diagnostic criteria :  
  • Loculated clear fluid in the pelvis.
  • The presence of incomplete septa within the dilated tube. This could be identified easily by scanning the tube in different planes by gentle rotation of the probe.
  • It has a retort shape but could be seen in multiple cross sections depending on the plane of scanning.

   

Longitudinal and cross-section views of the same hydrosalpinx
 
 
Dilated tubes usually drain back into the uterus during the luteal phase rendering them less identifiable by ultrasound. This is secondary to relaxation of the interstitial part of the tube induced by progesterone. Such tubes are called communicating hydrosalpinges. Accordingly pelvic scanning for tubal pathology should be timed to the pre-ovulatory phase of the cycle.

Hydrosalpinges and IVF

It is now an accepted fact that hydrosalpinges could significantly reduce pregnancy rate after IVF and they should be removed before starting such treatment.
 
However the practice of clip application to block the promixal part of these dilated tubes should be discouraged. Continuous secretion of fluid secondary to the elevated oestrogen levels during IVF treatment could lead to gross enlargement of these tubes without a relief route for drainage. This could lead to the following 3 problems depicted by the 3 pictures as well respectively: 
  • Difficulty during monitoring follicular growth in some cases due to ovarian displacement and the increased amount of fluid in the pelvis around them .  
  • Increased risk of tubal torsion due to the gross lateral enlargement of the tubes with narrow proximal part
  • Increased risk of infection  after transvaginal egg collection leading to pyosalpinges formation with turbid / particulate fluid.
 
  
Monitoring natural cycles

Serial ultrasound scan examinations during one or more menstrual cycles could add very important information which would be of help in infertility management. Different issues are examined including:

  • Early follicular phase scanning would show how many antral follicles are present which is an important point in studying ovarian reserve. On the other hand multiple and rapid recruitment could be signs of incipient ovarian failure especially in women with short follicular phase.
  • Rate of follicular growth and follicle size at ovulation. These are important for diagnosis of ovulation of small follicles after premature LH surge, failure of ovulation altogether as in luteinised unruptured follicle syndrome.
  • Follow up of endometrial growth and echo pattern. Normally an endometrium should at least reach 8 mm in thickness and show a trilaminar pattern. Failure of either or both by the time of ovulation are indications of reduced endometrial receptivity.   
  • Doppler studies of the subendometrial blood flow and uterine artery pulse wave give useful information regarding the blood flow within the uterus. As well peripheral vascularisation of a dominant follicle indicates imminent ovulation.  A relationship has been recorded between unexplained infertility and high uterine artery pulsatility index.

A dominant  follilce with  peripheral vascularisation within a polycystic ovary
 A sagittal view of a uterus showing midcycle trilaminar endometrium

Echogenic endometrium with persistent central echo

  • Occasionally moderate amount of fluid could be seen in the pouch of Douglas at midcycle. This could be utilised to see the fimbrial end of the tube in few cases. The patient might need to sit up a little bit to allow accumulation of the fluid in the pelvis.

                                       

The neighbouring picture shows the right ovary and fimbrial end of the right tube clearly demarcated by fluid in the pouch of Douglas

  Induction of ovulation

Serial ultrasound scan examinations for follicular number and growth and for studying changes in the shape and thickness of the endometrium improved patients' safety as well as results. However though careful monitoring did reduce the risk of ovarian hyperstimulation syndrome it did not eliminate it all together.   

  Invasive diagnostic ultrasonography
 
Saline infusion sonohysterography is becoming an important technique for investigating infertile women. It is very useful for excluding or confirming the presence of submucous fibroids, polyps, intrauterine adhesions and for studying the uterine cavity shape in a coronal view with 3-D ultrasonography.
 
Similarly Hysterosalpingo-Contrast-Sonography [HyCoSy] has already replaced X-ray hysterosalpingographyadhesions [HSG] for fallopian tubes studies in many centres avoiding the need for pelvic organs radiation.
 
 
3D rendered coronal view of a normal uterine cavity. Saline infusion sonohysterography gives more information.

3D rendered coronal view of a uterine cavity disrupted with intrauterine adheshions
Colour Doppler used to  demonstrate  a tube in a case  of  difficulty due to increased bowel shadows. See HyCoSy.
   
 
Invasive therapeutic ultrasonography

Within the fertility units transvaginal scanning helped a lot with certain therapeutic procedures including:

  • Cysts aspiration
  • Egg collection during IVF treatment cycles
  • Injection of ectopic pregnancy with potassium chloride or methotrexate.
  • Pregnancy related procedures including chorionic villus sampling, embryo reduction and amniocentesis.
 
 
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