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imaging in gyne

Introduction

Diagnostic U/S

      Normal pelvic appearance

      Pathological appearance

      Clinical applications

Other imaging modalities

     XR imaging

               HSG

    CT scan

    MRI

INTRODUCTION

Imaging is an important tool help in making diagnosis of many clinical problems in medicine and in our field we can say that imaging (mainly U/S) is our right hand in solving many clinical problems in gynecology and obstetrics

Diagnostic u/s is inexpensive and as a bedside test as part of the clinical examination.

The widely used abdominal u/s is now replaced by endovaginal u/s which is of high frequency and because of its close proximity to the pelvic organs provide better image than the abdominal u/s which in addition require a full bladder to visualize pelvic organs.

Other modalities like XR , CT , MRI are additional tools can aid in accomplishing the diagnosis.

Diagnostic ultrasound:

The technique employs high frequency (3-7.5)mHz low intensity pulsed sound waves, which are transmitted through the abdomen or pelvis by an ultrasound transducer.

Reflected signals from surfaces or discontinuities within organs are displayed as a 2 dimensional echo map and the frequent updates provide real-time information. Doppler u/s information can also be provided by the same transducer. The Doppler shifted signals can be displayed as a colour map of blood vessel on the top of the gray scale image.quantitative information about the actual velocity or resistance to flow can be obtained.

It is especially useful in gynecology because it cal show the process of normal (as in follicular growth, corpous luteum formation and endometrial proliferative phase) and abnormal (as in case of certain cancer) angiogenesis

Few notes about normal and abnormal appearance of the genital organs:

The uterus:

On TVUS the uterus and the cervix can be visualized and measured in longitudinal and transverse planes. The myometrium is of uniform grainy texture around a central endometrial strip. The endomt changing continuously in morphology and measurement throughout the menstrual cycle.

Initially it is thin <3mm but in the midcycle it has 3 distinct lines (triple layer) which indicate good receptivity.

In the luteal phase the endomet. become thick and white (scretory phase), and for the improvement of the uterine receptivity the uterine blood flow increase toward the luteal phase.

After the menopause the uterus become small and atrophic with very thin endomet. <5mm.

Abnormalities of the uterus:

Fibroid can easily be seen as round discrete structure arising in the myometrium, if the fibroid is so large it is better to be examined by transabdominal u/s.

Adenomyosis causes a diffuse thickening of the myometrium with spots of hypo and hyperechogenicity. Endometrial polyp can be seen as a localized thickening of the endomet.

Sometime by instilling saline into the uterine cavity we can visualize endometrial lesion and this is known as saline sonohysterography.

Ovaries:

Ovaries can be seen as lozenge- shape structure lateral to the uterus usually related to the internal iliac vein.

During the menstrual cycle the several follicle af about 5mm can be seen but after day 8 of the cycle a dominant follicle can be seen in one of the ovaries and prior to ovulation the dominant follicle diameter is about 20mm and after ovulation an irregular solid cystic structure, the corpus luteum can be seen. By Doppler u/s the  blood flow is increased just before ovulation, and become more intense in the vascular corpus luteum

Abnormalities of the ovaries are:

1- PCO as large sized ovaries necklace appearance of the peripherally arranged small follicles about 5mm in diameter round a dense central stroma with intensely vascular stroma by colour Doppler

2- ovarian cyst whether a functional simple cyst (thin walled and clear content) these usually disappear within 2-4 weeks or neoplastic cysts which have more complicated appearance (complex with locules or internal papillae)

3- dermoid cyst has mixture of different tissues inside (different echogenicities)

4- endometriotic cyst has ground glass appearance (unclotted blood)

Features of malignancy:

Complex cyst , bilateral, fixity, ascitis, and increased vascularity.

Fallopian tubes:

Normally not seen but if chronically iflamed destroyed tubes with hydrosalpnix or pyosalpnix can be seen as elongated retort shaped cystic structure adjacent to the uterus

Clinical applications of u/s in gynecology:

1- menstrual disorders like menorrhagia, oligomenorrhoea or hypomenorrhoea as in Asheman syndrome which can be demonstrated by saline sonohysterography

2- postmenopausal bleeding

3- In case of pelvic pain (acute as in ectopic pregnany or PID or complicated ovarian cyst) or chronic as in endometrioma of the ovaries

4- lower abdominal mass

5- Monitoring of infertility treatment

    For initial assessment of the genital organs by TVUS  then to monitor the infertility treatment to track the mature follicle to time the IUI

And to 1-determine the number of the follicle 2- to time the hCG injection

3- for the assistance in the aspiration of the oocytes as an ultrasound guided needle in IVF.

6- for early pregnancy scanning if it is normal or abnormal pregnancy:

By TVUS the pregnancy can be detected as a gestational sac from the 5^th wk of the LMP, and the FH pulsation at 6^th wk and then until 14 wks the GA is assessed by the CRL (crown rump length).

If there is bleeding and pain in early pregnancy it may be threatened miscarriage or ectopic pregnancy for accurate diagnosis we can do a quantitative B- hCG and TVUS

And in few words ectopic pregnancy can be suspected when the hCG is >1000 IU and there is no GS inside the uterus or there is free fluid in the peritoneal cavity or adnexial mass.

If GS is >20mm and there is no embryo inside it this condition is called blighted ovum.

And finally if there is an embryo inside the sac of > than 10 mm then the cardiac pulsation should be seen otherwise missed abortion is diagnosed.

Other imaging modalities:

Standard X-ray:

Rarely used but previously the calcifications in ovarian cyst was seen.

HSG ( hystero salpingo graphy) a standard method for the evaluation of the tubal patency and any filling defect inside the uterine cavity and see the spillage of the dye into the peritoneal cavity under a fluoroscope control.

This test should be done in the 9^th day of the cycle ( i.e. before ovulation to exclude pregnancy).

CT scanning:

It provide a good soft tissue images, it provide better information than U/S on parametrial spread of cervical cancer and lymph nodes metastasis.

After radiotherapy a CT scanning is not differentiating between fibrosis and tumor recurrence.

MRI:

This technique does not use ionizing radiation and it can produce sectional images in any plane. And the female pelvis is a good area for MRI because it is away from respiratory movement.

It is better than U/S in staging of the endometrial cancer because it can show the myometrial invasion.

It is better than U/S in the detection of the ovarian cancer recurrence.

It can visualize the pelvic floor effectively and can detect small deposits of endometriosis.