What is Fertility Scan ?
Investigation of the probable cause of infertility is complex and in many instances a complicated process.
Investigation of the woman is based upon the availability of high quality ultrasound with Doppler, preferably 3D USG facilities and usually involves assessment of tubal patency.
Thus, the ultrasound scan for the fertility assessment should be “one-stop procedure” called the ‘fertility scan’
To yield the best results, the scan must be performed transvaginally and the equipment should be of high resolution with sensitive colour and spectral Doppler modalities. A three dimensional (3D) facilitycan provide additional valuable information.
What’s the best time to do such scan ?
Timing of the scan is also important and should be performed at a time which maximises the amount and quality of information provided,
While an assessment of number of potential eggs in each ovary ( antral follicles) are best assessed within first few days of period, whether a ‘good’ dominant follicle (egg) is present, improved ability to diagnose polycystic ovaries and the ability to assess the uterine lining (endometrium) response to egg development to receive an embryo – all favour performing the scan on day 10-12.
How Uterus is examined ?
Dimensions and position of uterus (anteverted or retroverted – both are normal ), whether the uterus is mobile and it’s relation to surrounding organs (e.g. bladder, bowel) are assessed.
Excluding gross abnormalities of the uterus such as congenital anomalies , large tumours (fibroids ), polyps, evidence of adenomyosis in uterine wall are all important .
A trilaminar appearance (triple line) with a minimum thickness of 7 mm of the lining of uterus and a uterine artery blood flowaround mid cycleare regarded as reliable markers of good endometrial receptivity to receive an emryo.
How fallopian tubes are examined ?
Normal tube is usually invisible on ultrasound unless there is free fluid present in pelvis.
We look for tubal abnormalities like swollen tubes (hydrosalpinx) suggestive of tubal disease.
Hystero-contrast sonography (HyCoSy)offers an alternative to HSG to check whether tubes are open or not. Hydrosonography( SIS) is part of the HyCoSy test for enhancedevaluation of uterine cavity.
Total pain scores for HyCoSy are reported to be significantly lower than for HSG in the majority of patients.
How ovaries are examined ?
Ovaries should be measured in three planes and possibly ovarian volume be calculated.
Each ovary should contain 5-10 antral follicles (potential eggs in each ovary) with good blood flow.
There should be a dominant follicle in one of the ovaries of about 16-18 mm in diameter with a circle of blood vessels around the follicle demonstrated on colour or power Doppler in mid cycle before release of eggs.
On day 10-12 of the cycle normal ovaries can be easily differentiated from those that are polycystic ovaries
When the ovarian volume is less than 3 ml or there are less than five antral follicles between the two ovaries, ovarian reserve is diminished.
Apart from assessing antral count, size of ovaries and diagnosis of polycystic ovaries, any gross pathologies of the ovaries like ovarian tumours and complex ovarian cysts are also assessed.
Detail assessment of an ovarian cyst involve character of a cyst wall (smooth versus irregular) and intracystic anatomic appearance (septated / papillary) to assist in establishing the likelihood of a tumour, inflammatory or endometrioticprocess, as opposed to a simple functional cyst.
What else can be seen through such procedure ?
To differentiate a pelvic infection from appendicitis, urinary tract infection, and complications of a bleeding ovarian cyst, all of which can cause lower abdominal pain.
After the infectious episode, patient may present with a pelvic mass, which can be seen.
Why 3D Ultrasound ?
Three-dimensional ultrasound (3D USG) is a fast-evolving imaging technique that holds a great potential for use in gynaecology. Patients can benefit in adding 3D USG to their routine gynaecological workup as it provides fast and accurate results in a relative cost effective way , compared to CT Scan or MRI.
As in two-dimensional ultrasound (2D USG), transvaginal approach is preferred in gynaecologic examination with 3D USG.
Here are some of the reasons for specially using the 3 D USG by TVS
- Detection of congenital uterine anomalies
- Defining and mapping uterine lesions such as fibroids, very valuable when making clinical decisions and surgical planning.
- Assessing the Ovaries by Sonography-based Automated
Volume Calculation (Sono AVC) is one for counting antral follicles and monitoring follicular growth
