Imaging Flashcards
what imagining methods are used in obs and gynaecologiy
Ultrasound CT MRI X-ray screening fluoroscopy Functional imaging - PET CT
what are the indications for imaging in obs and gynae
Diagnosis of pelvic pain
Assessment of pelvic masses
Investigation of abnormal menstrual bleeding
Assessment of patients with post-menopausal bleeding
Investigation of infertility
Interventional radiology (Fallopian tube recanalisation, uterine artery embolisation etc)
what are the 2 main ultrasound techniques
transabdominal
-scanning using a standard general abdominal US transducer
transvaginal
-scanning using a dedicated end-cavity high frequency transducer
what happens in a transabdominal ultrasound
pelvic organs are scanned through the anterior abdominal wall
perform brief assessment of upper abdomen
the patient must have a full bladder
-acts as an acoustic window
displaces gas filled bowel loops out of the pelvis
what are the benefits of trans abdominal ultrasound
safe
readily available
no ionising radiation and therefor ideal for children and women of reproductive age
what are some disadvantages of trans abdominal ultrasound
difficult to obtain good images in obese patients
operator dependent
difficult to produce the exact same image every time (not good for assessing response to treatment)
why are the external iliac vessels important landmarks in trans abdominal ultrasound
land marks for the ovaries
follow them down to find ovaries
why is transvaginal ultrasound clearer than trans abdominal
higher frequency and gets to closer proximity to the uterus
advantages of transvaginal scanning
excellent depiction of the pelvic organs
disadvantages of transvaginal scanning
more invasive procedure
not suitable for those who haven’t been sexually active
sometimes just demonstrates ‘tip of the iceberg’ and not full extent of large pelvic masses
how do you asses the ovarian volume
take a transvaginal ultrasound scan
one horizontal and one vertical
make 3 points and measure
when is CT used in obs and gynae
2nd line after ultrasound
acute abdominal pain
post -surgical complications
staging of gynaecological malignancy
assessing response to treatment (chemo/radio)
advantages for CT
quick
entire chest, abdomen and pelvis asses in one scan
can take ‘multi slice’ images through the patient allowing you to view the image in 3 different planes
disadvantages of CT
high radiation dose -significant dose given to ovaries
used sparingly in children and patients of reproductive age
does not provide optimal depiction of pelvic organs
when is MRI scanning used in obs and gynae
cancer staging (especially cervical)
further evaluation and characterisation of adnexal and uterine masses
evaluation of patients with sub-fertility
MR of the pituitary if suspected prolactinoma
advantages of MRI
provides excellent depiction of pelvic organs
no ionising radiation
can give some idea about the composition of soft tissue masses
disadvantages of MRI
time consuming
poor depiction of lung parenchyma - need CT if worried about pulmonary mets
not tolerated if patients have claustrophobia
contra indicated in patients with pacemakers
what imaging to you use to diagnose endometriosis
MRI scan
endometriosis deposits contained altered blood and haemoglobin degredation products
these cause MR signal changes
Altered blood looks white on T1 scan
what is a dermoid cyst
tissue derived from ectoderm, mesoderm and endoderm
can contain a mixture of many types of tissue but most contain a large amount of fat
can be diagnosed on MRI or CT
what is a hysterosalingography
X-ray screening - real time imaging
for assessment of tubal potency in patients with infertility
can also asses outline of uterine cavity
procedure usually completed in 3-5 minutes
cervix cannulated and contrast instilled to fill the uterine cavity - should travel though the uterine tubes
how do you image to asses cancer treatments
take baseline scan to compare further ones to
how does ovarian cancer spear
via the perineum
ct scanning needed for radiological staging
what do you need to determine when staging cervical cancer
- spread to parametrium
- extension into vagina
- infiltration of adjacent organs
- mets to regional lymph nodes
MR T2 used to depict local disease
CT used for distant mets
how do you investigate endometrial cancer
Transvaginal ultrasound if thickened endometrium
MR used to asses degree of myometrial invasion
CT for distant mets
most are obese and too large for narrow MR scanners
