Imaging in Gynaecology Flashcards
What imaging methods can be used in gynaecology?
- Ultrasound
- CT
- MRI
- X-ray fluoroscopy – e.g. hysterosalpingograms (HSG)
- Functional imaging – PET-CT
What indications would make you consider gynaecological imaging?
- pelvic pain
- pelvis mass
- abnormal menstrual bleeding
- post menopausal bleeding
- infertility
In what gynaecological cases may you consider interventional radiology?
- Fallopian tube recanalisation (clear blockages)
- uterine artery embolisation
When may a pituitary MRI be considered alongside gynaecological imaging?
If patients bloods show high prolactin
may be coming from a pituitary adenoma
Where can a gynaecological US scan be performed?
- Radiology departments
- Gynaecology clinics
- Some GP practices
What disadvantage is there with conducting a gynaecological US outwith of the radiology department?
- Images aren’t stored on same electronic database
=> patient has an incomplete imaging record
=> difficulty for comparison of serial scans
What two US techniques can be used to image suspected gynae pathology?
Transabdominal - general abdominal US transducer
Transvaginal - high- frequency transducer
A transabdominal and transvaginal US cannot be performed on the same attendance to clinic. TRUE/FALSE?
FALSE
both techniques are used at the same attendance
During a transabdominal US, clinians have a quick scan of the upper abdomen. Why may they do this and what are they looking for?
- ensure that there is no hydronephrosis
- detect early ascites
- check pelvic abnormality is not secondary to upper abdominal pathology
Why must a patients bladder be FULL on a transabdominal US?
- bladder acts as an “acoustic window”
- distended bladder displaces gas-filled bowel loops out of the pelvis
- bowel gas usually scatters the US beam => poor image quality
What are the drawbacks of transabdominal US?
- difficult to obtain good images in obese patients
- difficult if patients have gaseous distension of bowel
- Operator dependent
- difficult to produce same images every time => NOT used to assess response to cancer tx
What structures can normally be visualised on a transabdominal US?
Bladder (dark as it is FULL of fluid)
Uterus and endometrial lining (lining is brighter on scan)
Ovary or vagina may also be seen on scan
What vessels lie in closes proximity to the ovary and therefore act as a landmark on Transabdominal scanning?
External iliac artery and vein
Why does transvaginal US need to be closer to the target organ?
- Higher frequency waves => shorter wavelength => dont travel as far
- Higher frequency waves scatter in the body
=> transducer has to be close to the target organ
Does a transvaginal US require a full or empty bladder?
Empty
(a full bladder can make the examination uncomfortable).
What are the disadvantages of a TVUS?
- More invasive
- Not suitable for individuals who have not been sexually active
- may not depict full extent of large pelvic masses
In what situations is CT used to investigate suspected gynaecological pathology?
- 2nd line investigation (after US) in acute abdominal pain
- Surgical complications – e.g.small bowel obstruction secondary to adhesions, post-op collections/abscesses etc.
- Stage Gynaecological malignancy
- Assess response to treatment (chemo+/-radio)
What are the main disadvantages of CT scanning?
- High radiation dose (160 CXRs)
- significant dose to ovaries
=> used sparingly in children and patients of reproductive age - MR is better at providing good tissue resolution of pelvic organs
What type of energy is used in an MRI and is this harmful?
radiofrequency energy rather than ionising
=> NOT harmful
Why are different MRI sequences used in scans?
- define the tissue composition in the body area being
scanned - e.g. T1 fat suppression scan can be used to check for dermoid cyst
T2 - Fluid = bright white
T1 - Blood, protein and fat = white
What are the main disadvantages of MRI?
- Time-consuming
- Poor depiction certain orans (e.g. lungs)
- Not tolerated claustrophobic
- Contra-indicated - pacemakers, metallic heart valves, cochlear implants etc
When are MRI scans normally indicated to investigate gynaecological patients?
- Cancer staging – esp. cervical cancer
- Further analysis of adnexal and uterine masses
- Evaluation of sub-fertility – are there are contributory anatomical variations in the pt?
- MRI pituitary gland if suspected prolactinoma
How can endometriosis show characteristic signs on MRI?
- 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)
What are dermoid cysts and what do they contain?
Dermoid cysts = also known as ovarian teratomas
- contain tissue derived from ectoderm, mesoderm and endoderm
- contain a mixture of tissues, but most contain a large amount of fat
What scan is used to assess tubal patency with radio-opaque dye? And how long does this procedure take?
- Hysterosalpingography
- X-ray screening procedure – real-time imaging
- Procedure usually completed ~3-5 minutes
- Cervix is cannulated
- radiopaque contrast instilled to fill the uterine cavity and spill out of fallopian tubes
How does ovarian cancer spread ?
Disseminates by peritoneal spread
What causes the abdomen to be distended in ovarian cancer?
ascites - fluid round the abdomen
What other collection of fluid is common in ovarian cancer?
Malignant pleural effusions can result from spread of disease via pleuro-peritoneal communications
L
Initial diagnosis is often made by ultrasound (ovarian masses)
CT scanning is the usual method used for radiological staging
What type of spread is UNCOMMON in ovarian cancer?
- Lymph node mets
- Lung mets
- hepatic mets
LESS common - usually patients displaying these have cancers with the BRCA1 mutation
What scans are used to diagnose and stage ovarian cancer?
Diagnosis - ultrasound (ovarian masses)
Staging - CT scan
What spread of disease do you need to look out for in cervical cancer?
- Spread into the parametrium (adj. to cervix)
- Extension into the vagina
- Infiltration of adjacent organs: rectum, ureters, urinary bladder
- Metastases to regional lymph nodes (internal iliac and obturator)
What scans are used to determine the extent of local disease and distant disease in cervical cancer?
Local - MRI
Distant - CT
What women are most likely to develop endometrial cancer and what signs of this can be picked up on TVUS?
- Post menopausal women (complaining of bleeding)
- abnormally thickened endometrium
PMB
What scans are used to assess local and distant disease in Endometrial cancer?
MRI used for degree of myometrial invasion
CT scan used to look for distant metastases
Why may MRI be contraindicated or not work for patients with endometrial cancer?
Many patients with endometrial carcinoma are obese
=> may be too large for the narrow bore of MR scanners
