Imaging in Obs and Gyn

Question 1

What imaging techniques are used in obs and gyn?

Answer 1

Ultrasound

CT

MRI

X-ray screening fluoroscopy – e.g.
hysterosalpingograms (HSG)

Functional imaging – PET-CT

Question 2

What are indications for using radiology in obs and gyn?

Answer 2

Diagnosis of pelvic pain – looking to check for cause

Assessment of pelvic masses

Investigation of abnormal menstrual bleeding

Assessment of patients with post-menopausal bleeding (in Tayside, these patients tend be scanned by the gynaecology team at the PMB/post-menopausal bleeding clinic)

Investigation of infertility (these patients may also undergo MR scanning of the pituitary)

Interventional radiology – fallopian tube recanalisation, uterine artery embolisation etc

Question 3

What is the most common investigation type for gynaecological imaging?

Answer 3

Ultrasound scan

Used commonly in gynaecological and also in ante-natal circumstances

Question 4

What are the pros of using ultrasound scanning in obs and gyn?

Answer 4

Relatively cheap

Safe – no ionising radiation

Provides very good definition of different pelvic organs

Can be used in the clinic as an adjunct to pelvic examination

Question 5

What are the 2 main ultrasound techniques used in obs and gyn?

Answer 5

Transabdominal - scanning using a standard general abdominal US transducer

Transvaginal - scanning using a dedicated endocavity high- frequency transducer

Both techniques can be used during the same visit

Question 6

How are pelvic organs scanned in transabdominal ultrasound?

Answer 6

The pelvic organs are scanned through the anterior abdominal wall

Question 7

A brief assessment can be used before transabdominal US, what can this check for?

Answer 7

To ensure that there is no hydronephrosis

To detect early ascites

To ensure that the pelvic abnormality is not secondary to upper abdominal pathology

Question 8

Why must patient have full bladder during transabdominal US?

Answer 8

The urine-distended bladder acts as an “acoustic window”

A distended bladder displaces gas-filled bowel loops out of the pelvis (bowel gas scatters the ultrasound beam and degrades image quality)

Question 9

Advantages of transabdominal US?

Answer 9

• Safe
• Readily available
• No ionising radiation and therefore ideal for children and women of reproductive age

Question 10

Disadvantages of transabdominal US?

Answer 10

• It is difficult to obtain good images in obese patients and in patients where there is gaseous distension of the bowel
• Operator dependent (the quality of the ultrasound examination is dependent in large part on the skills of the operator).
• It is difficult to produce exactly the same images every time the patient attends and this means ultrasound is not often used for assessing the response to cancer treatment

Question 11

Transvaginal ultrasound requires patient to have full bladder. True/false?

Answer 11

False

Transabdominal US requires full bladder.

Transvaginal US prefers an empty bladder as a full bladder can make the examination uncomfortable

Question 12

Advantages of transvaginal scanning?

Answer 12

Excellent depiction of the pelvic organs

Question 13

Disadvantages of transvaginal scanning?

Answer 13

More invasive procedure

Not suitable for individuals who have not been sexually active

Can sometimes just demonstrate “the tip of the iceberg” and may not depict the full extent of large pelvic masses (ideally transvaginal scan should follow a transabdominal scan which allows better overview)

Question 14

CT scanning can often be used as a second-line investigation after ultrasound in patients presenting with acute abdominal pain. True/false?

Answer 14

True

Question 15

What can CT scanning be used for in obs and gyn?

Answer 15

Can be used to assess post-surgical complications – e.g.small bowel obstruction secondary to adhesions, post-operative collections/abscesses etc.

Staging of gynaecological malignancy, especially ovarian and endometrial cancers

Assessing response to treatment in patients after chemotherapy +/- radiotherapy

Question 16

Advantages of CT scanning in obs and gyn?

Answer 16

Quick

The entire chest abdomen and pelvis can be assessed on one scan

Modern multiple detector row (“multislice”) scanners produce very thin slices and images can be manipulated to produce coronal and sagittal reformats, as well as the axial source images

Question 17

Disadvantages of CT scanning in obs and gyn?

Answer 17

High radiation dose (equivalent to about 160 chest x-rays) with a significant dose delivered to the ovaries

Therefore used sparingly in children and patients of reproductive age

Does not provide optimal depiction of different pelvic organs (MR is better at providing good tissue resolution)

Question 18

MRI scanning uses ionising radiation. True/false?

Answer 18

False

Uses radiofrequency energy rather than ionising radiation

Question 19

Advantages of MRI scan?

Answer 19

Provides an excellent depiction of pelvic organs

No ionising radiation and is therefore suitable for children and women of reproductive age

Can give some idea about the composition of soft tissue masses – e.g. do they contain fluid, fat, blood etc

Question 20

Disadvantages of MRI scan?

Answer 20

Time-consuming

Poor depiction of lung parenchyma – a CT scan should be performed if there is query about pulmonary metastases

Not tolerated if patients have claustrophobia

Contra-indicated in patients with: pacemakers, many artificial metallic heart valves, nerve stimulators, cochlear implants etc.

Question 21

What specific uses of MRI in obs and gyn?

Answer 21

Cancer staging – especially cervical cancer

Further evaluation and characterisation of adnexal and uterine masses, where pelvic ultrasound or other imaging have not provided a diagnosis

Evaluation of patients with sub-fertility

MR of the pituitary gland is performed in patients with suspected prolactinoma

Question 22

Endometriosis may be difficult to diagnose, what technique could patients require?

Answer 22

Diagnostic laparoscopy

Question 23

How can endometriosis be diagnosed on MRI scan?

Answer 23

Endometriosis deposits contain altered blood and haemoglobin degradation products.

These degradation products cause characteristic MR signal changes, and, in the appropriate clinical context, endometriosis can be diagnosed on MRI scans.

Question 24

What are dermoid cysts?

Answer 24

Also known as ovarian teratomas and contains tissue derived from ectoderm, mesoderm and endoderm. They can therefore contain an admixture of many types of tissue, but most contain a large amount of fat.

Question 25

What is HSG (hysterosalpingography) and its use?

Answer 25

X-ray screening procedure – real-time imaging

For assessment of tubal patency in patients with infertility

Can also assess outline of uterine cavity

Question 26

How long does HSG procedure usually take to complete?

Answer 26

Procedure usually completed ~3-5 minutes

Question 27

What is the classification for cancer staging?

Answer 27

Cancers are staged using the TNM (Tumour Nodes Metastases) classification

Question 28

Why is establishing the stage of the cancer important in treatment?

Answer 28

Staging plays an important role in treatment planning and can assist in discussions about the patient’s prognosis

A pre-treatment scan serves as a “baseline” study so that subsequent scans can be used to assess response to treatment (chemotherapy, radiotherapy etc)

Question 29

How does ovarian cancer disseminate?

Answer 29

By peritoneal spread

Question 30

Imaging used for initial diagnosis of ovarian cancer?

Answer 30

Ultrasound (ovarian masses)

Question 31

What is the usual method used for radiological staging of ovarian cancer?

Answer 31

CT scan

Question 32

What cancers are linked to the BRCA 1 gene?

Answer 32

Ovarian and/or breast cancer

Question 33

When staging cervical cancer, what is important to note?

Answer 33

Important to determine whether there is:

• Spread into the parametrium
• Extension into the vagina
• Infiltration of adjacent organs: rectum, ureters, urinary bladder
• Metastases to regional lymph nodes (internal iliac and obturator)

Question 34

For endometrial cancer, what is the best method of establishing abnormally thickened endometrium in a post-menopausal patient with PMB?

Answer 34

Transvaginal ultrasound

Question 35

Uses of MRI and CT in endometrial cancer?

Answer 35

MR scanning can be used to assess the degree of myometrial invasion

CT scanning is used to look for distant nodal metastases and pulmonary metastases

Question 36

Why can MRI scanning be a problem for patients with endometrial cancer?

Answer 36

Many patients with endometrial carcinoma are obese, and they may be too large for the narrow bore of MR scanners