Imaging in gynaecology 2 Flashcards
What are the uses of CT scanning in gynaecology ?
- Often used as a second-line investigation after ultrasound in patients presenting with acute abdominal pain
- 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
What are the advantages and disadvantages of CT scanning in gynaecology ?
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)
Go over abdo CT structures
Describe the 2 main different types of MRI scan and what they look at
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
What are the advantages and disadvantages of MRI scans ?
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.
What are the uses of MRI scans in gynaecology ?
- 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 – are there are contributory anatomical variations?
- MR of the pituitary gland is performed in patients with suspected prolactinoma
Go over this normal MRI of the female pelvis
What abnormality is shown in this MRI ?
Uterine fibroid
What abnormality is shown in this MRI ?
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.
Describe the role of MRI in diagnosing endometriosis and also how endometriosis may appear on scan
- 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
Describe the appearnace of dermoid cysts on MRI
They can contain an admixture of many types of tissue, but most contain a large amount of fat.
What is Hysterosalpingography (HSG) used for ?
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
Describe HSG procedure
- Cervix is cannulated and radiopaque contrast instilled to fill the uterine cavity
- Once contrast instilled, a series of images are captured as the contrast fills uterine cavity, then into fallopian tubes and spills into peritoneal cavity
How are gynaecological cancers staged ?
TNM staging
What imaging modality is usually used to diagnose ovarian cancer ?
US
