Imaging Flashcards
imaging methods in obs and gynae?
US mainly CT MRI X ray screening fluroscopy (e.g hysterosalpingograms) functional imaging (PET CT)
indications for imaging?
pelvic pain
assessment of pelvic masses
investigation of abnormal menstrual bleeding
post menopausal bleeding
investigation of infertility
interventional radiology (e.g fallopian tube recanalisation, uterine artery embolisation etc)
how are US scan images stored?
electronically via PACS
- scans done outside of radiology clinic may not appear on PACS
2 main US techniques?
transabdominal
- scan using a standard general abdominal US transducer
- first line
transvaginal
- scan using a dedicated endocavity high-frequency transducer
- 2nd line
often both used in same appointment
how is transabdominal US performed?
pelvic organs are scanned through anterior abdominal wall
should perform a brief assessment of upper abdomen (ensure theres no hydronephrosis, ascites or any other pathology causing the pelvic symptoms)
patient must have a full bladder
why must the patient have a full bladder for transabdominal US?
distended bladder acts as an acoustic window
distended bladder displaces gas filled loops out of the pelvis (bowel gas scatters the US beam and degrades image quality)
advantages of TA US?
safe
readily available
no ionising radiation and therefore ideal for children and women of reproductive age
disadvantages of TA US?
difficult to obtain good image in obese patients or people with gaseous distention of bowel
operator dependant
difficult to produce exact same image every time the patient attends clinic which means US is often not used for assessing the response to cancer treatment etc
important landmarks in scanning for ovaries?
external iliac arteries
follow them down and should lead to ovary
how is TV (transvaginal) US different to TA?
higher frequency
shorter wavelength
better spatial resolution
requirements before TV US and why?
patient must have an empty bladder
- can make scan uncomfortable
- higher frequency is more likely to be scattered in body so transducer has to be close as possible to the target organ
advantage of TV US?
excellent depiction of pelvic organs
disadvantages of TV US?
more invasive
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
how can TV US be used in ovarian disorders?
can assess size of ovary (e.g PCOS)
can visualise follicles
when is CT scan used?
2nd line after US in patients presenting with acute pain
assess post surgical complications (bowel obstruction, abscesses etc)
stage gynae malignancy (esp ovarian and endometrial)
assess response to treatment in patients after chemotherapy