Imaging in gynaecology 2

Question 1

What are the uses of CT scanning in gynaecology ?

Answer 1

1. Often used as a second-line investigation after ultrasound in patients presenting with acute abdominal pain
2. Can be used to assess post-surgical complications – e.g.small bowel obstruction secondary to adhesions, post-operative collections/abscesses etc.
3. Staging of gynaecological malignancy, especially ovarian and endometrial cancers
4. Assessing response to treatment in patients after chemotherapy +/- radiotherapy

Question 2

What are the advantages and disadvantages of CT scanning in gynaecology ?

Answer 2

ADVANTAGES:

• 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

DISADVANTAGES:

• High radiation dose, 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 3

Go over abdo CT structures

Question 4

Describe the 2 main different types of MRI scan and what they look at

Answer 4

T1 images – 1 tissue type is bright – FAT e.g. subcutaneous fat (SC fat) and bone marrow

T2 images – 2 tissue types are bright – FAT and WATER e.g. CSF

Question 5

What are the advantages and disadvantages of MRI scans ?

Answer 5

ADVANTAGES:

• Provides an excellent depiction of pelvic organs
• No ionising radiation ==> 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 ?

DISADVANTAGES:

• 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 etc.

Question 6

What are the uses of MRI scans in gynaecology ?

Answer 6

1. Cancer staging – especially cervical cancer
2. Further evaluation and characterisation of adnexal and uterine masses, where pelvic ultrasound or other imaging have not provided a diagnosis
3. Evaluation of patients with sub-fertility – are there are contributory anatomical variations?
4. MR of the pituitary gland is performed in patients with suspected prolactinoma

Question 7

Go over this normal MRI of the female pelvis

Question 8

What abnormality is shown in this MRI ?

Answer 8

Uterine fibroid

Question 9

What abnormality is shown in this MRI ?

Answer 9

Hydrosalpinx - a distally blocked fallopian tube filled with serous or clear fluid. The blocked tube may become substantially distended giving the tube a characteristic sausage-like or retort-like shape.

Question 10

Describe the role of MRI in diagnosing endometriosis and also how endometriosis may appear on scan

Answer 10

• Endometriosis can be difficult to diagnose and patients may need diagnostic laparoscopy
• 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 (but not really used often to diagnose it)
• Altered blood returns high-signal on T1 sequences (i.e. it looks white on the scan) whereas it returns lower signal on T2 sequences (looks grey)
• Fat can also look white on T1 weighted scans but it appears dark on special fat-suppression sequences

Question 11

Describe the appearnace of dermoid cysts on MRI

Answer 11

They can contain an admixture of many types of tissue, but most contain a large amount of fat.

Question 12

What is Hysterosalpingography (HSG) used for ?

Answer 12

For assessment of tubal patency in patients with infertility - Women who are not known to have comorbidities (such as pelvic inflammatory disease, previous ectopic pregnancy or endometriosis) should be offered hysterosalpingography (HSG) to screen for tubal occlusion

Question 13

Describe HSG procedure

Answer 13

1. Cervix is cannulated and radiopaque contrast instilled to fill the uterine cavity
2. Once contrast instilled, a series of images are captured as the contrast fills uterine cavity, then into fallopian tubes and spills into peritoneal cavity

Question 14

How are gynaecological cancers staged ?

Answer 14

TNM staging

Question 15

What imaging modality is usually used to diagnose ovarian cancer ?

Answer 15

US

Question 16

What imaging modality is often used to stage ovarian cancer ?

Answer 16

CT scan

Question 17

How does ovarian cancer usually spread?

Answer 17

• Disseminates by peritoneal spread
• Ascites, omental and peritoneal nodules are common. Sub-diaphragmatic deposits and deposits on the surface of the liver are also seen

Question 18

What is it important to determine when staging cervical cancer ?

Answer 18

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 19

What imaging modality is mainly used to stage cervical cancer ?

Answer 19

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 – e.g. lung, para-aortic and mediastinal lymphadenopathy

Question 20

What is the 1st line imaging method for patinets with post-menopausal bleeding (PMB)?

Answer 20

TVS this is done to identify women with thickened endometrium which makes endometrial cancer diagnosis mor likely - they would then get an endometrial biopsy via hysteroscopy to provide a definite diagnosis

Question 21

What imaging is used to stage endometrial cancers ?

Answer 21

MR scanning can be used to assess the degree of myometrial invasion but CT scanning is used to look for distant nodal metastases and pulmonary metastases

So think CT