Imaging assessment in Gynaecology

Question 1

What imaging methods are used in obstetrics and gynaecology?

Answer 1

• Ultrasound
• CT
• MRI
• X-ray screening fluoroscopy - e.g. hysterosalpingograms (HSG)
• Functional imaging- PET CT

Question 2

What are the indications for using radiology in obs & gynae?

Answer 2

• Diagnosis of pelvic pain – 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 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

Why is ultrasound used so commonly?

Answer 3

Cheap

No ionising radiation

Very good definition of different pelvic organs

Can be used in clinic as an adjunct to pelvic examination

Question 4

What are the two main US techniques?

Answer 4

Transabdominal: standard general abdominal US transducer

Transvaginal: dedicated endocavity high-frequency transducer

Question 5

How is transabdominal ultrasound performed?

Answer 5

Pelvic organs are scanned thorugh the anterior abdominal wall

Question 6

Why should a brief assessment of the abdomen be performed before transabdominal ultrasound?

Answer 6

• 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 7

Why must a patient have a full bladder for a transabdominal ultrasound?

Answer 7

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 US beam and degrades image quality)

Question 8

What are the advantages of transabdominal ultrasound?

Answer 8

• safe
• readily available
• no ionising radiation and therefore ideal for children and women of reproductive age

Question 9

What are the disadvantages of transabdominal ultrasound?

Answer 9

• difficult to obtain good images in obese patients or when there is distension of the bowel
• operator dependant
• can’t get the same images every time- cant be used for assessing response to cancer treatment

Question 10

What are the advantages of transvaginal ultrasound scanning?

Answer 10

Excellent depiction of the pelvic organs

Question 11

What are the disadvantages of transvaginal scanning?

Answer 11

• More invasive procedure
• Not suitable for indivuduals who have not been sexually active
• Can sometimes not depict the full extent of pelvic masses

Question 12

What is often used as a second-line investigation after ultrasound in patients presenting with acute abdominal pain?

Answer 12

CT scaninng

Question 13

What can CT scanning be used for?

Answer 13

• assess post surgical complications
  
  • small bowel obstruction secondary to adhesions
  • post-operative collections/abscesses
• staging of gynaecological malignancy, especially ovarian and endometrial cancers
• assessing response to treatment in patients after chemotherapy +/- radiotherapy

Question 14

What are the advantages of CT scanning?

Answer 14

• quick
• the entire chest and abdomen can be assessed on one scan
• modern multiple detector row (multislice) scanners

Question 15

What are the disadvantages of CT scanning?

Answer 15

• high radiation dose (160 chest x-rays) with a significant dose to ovaries
• doesn’t provide optimal depiction of different pelvic organs

Question 16

MRI scanning uses what rather than ionising radiation?

Answer 16

Radiofrequency energy

Question 17

What are the advantages of MRI?

Answer 17

• provides excellent depiction of pelvic organs
• NO ionising radiaiton
• can give some idea about the composition of soft tissue masses- fluid, fat, blood

Question 18

What are the disadvantages of MRI?

Answer 18

• time consuming
• poor depiction of lung parenchyma- a CT scan should be performed if there is query about pulmonary metastases
• not tolerated if patents have claustrophobia
• contra-indicated in patients with;
  
  • pacemakers
  • artificial metallic heart valves
  • nerve stimulators
  • cochlear implants

Question 19

What are the uses of MRI in gynaecology patients?

Answer 19

• cancer staging- especially cervical
• evaluation and characterisation of adnexal and uterine masses, where pelvic US or other imaging techniques havent provided a diagnosis
• evaluation of patients with sub-fertility- are there contributory anatomical variations
• MR of pituitary glands is performed in patients with suspected prolactinoma

Question 20

Why can endometriosis be diagnosed on MRI scans?

Answer 20

As deposits contain altered blood and haemoglobin degradation products. These degradation products cause characteristic MR signal changes.

Altered blood returns high-signal on T1 weighted sequency (looks white on scan) whereas it returns lower signal on T2 sequences (looks grey)

Question 21

What is contained in a dermoid cyst?

Answer 21

Tissue derived from ectoderm, mesoderm and endoderm.

There can be a mixture of tissue but mostly fat

Question 22

What is hysterosalingography?

Answer 22

X-ray screening procedure- real-time imaging for assessment of tubal patency in patients with infertility

can also assess outline of uterine cavity

Question 23

How long dues hysterosalpingography take and how is it done?

Answer 23

Usually completed in 3-5 minutes

Cervix is cannulated and radiopaque contrast instilled to fill the uterine cavity- just before the contrast a scout ‘control film’ is obtained

Once instilled a series of images are captured as the contrast fills cavity then spills into peritoneal cavity

Question 24

How does ovarian cancer disseminate?

Answer 24

By peritoneal spread

Question 25

In ovarian cancer;

Ascites, _____ and ________ nodules are common

Sub-________ deposits and deposits on the surface of the _____ are also seen.

Answer 25

Ascites, omental and peritoneal nodules are common

Sub-diaphragmatic deposits and deposits on the surface of the liver are also seen.

Question 26

What do pleuro-peritoneal communications result in?

Answer 26

Malignant pleural effusions can result from spread of disease via pleuro-peritoneal communications

Question 27

Who tends to get lymph node, lung and hepatic metastases of ovarian cancer?

Answer 27

In patients in whom the disease behaviour has been modulated by chemotherapy or in cancers with the BRCA1 mutation

Question 28

how is the initial diagnosis of ovarian cancer made?

Answer 28

By ultrasound (ovarian masses)

Question 29

What is used for radiological staging of ovarian cancer?

Answer 29

CT scanning

Question 30

What must be determined when staging cervical cancer?

Answer 30

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 31

In cervical cancer __ (especially __ _______ sequences) is far better than __ at depicting local disease, but __ is often used to determine whether or not there are ______ _______.

Answer 31

In cervical cancer MR (especially T2 weighted sequences) is far better than CT at depicting local disease, but CT is often used to determine whether or not there are distant metastases.

Question 32

What is the best method of determining wether the endometrium is abnormally thickened?

Answer 32

Transvaginal ultrasound

Question 33

What is used to assess the degree of myometrial invasion in endometrial cancer?

Answer 33

MR scanning