Imaging in gynaecology Flashcards
What imaging methods are utilised in gynae radiology?
In order of most useful: USS CT MRI X-ray (HSG) PET
What are the indications for gynae radiology?
Dx of pelvic pain
Assessment of pelvic masses
Ix of AUB
Assessment of post-menopausal bleeding (endometrial thickness)
Ix of fertility (HSG, MR pituitary)
IR; fallopian tube recanalisation, uterine artery embolisation
What are the 2 USS techniques utilised in gynae?
Transabdominal
Transvaginal - detailed scan of uterus and ovaries
What is a transabdominal ultrasound?
Pelvic organs are scanned through the anterior abdominal wall
What should be included in a brief assessment in the transabdominal USS?
Hydronephrosis
Early ascites
Ensure that the pelvic abnormality is not secondary to upper abdominal pathology
Why must the patient have a full bladder for a transabdominal USS?
A urine-distended bladder acts as an acoustic window
A distended bladder displaces gas filled bowel loops out of the pelvis (bowel gas scatters USS beam and degrades image quality)
Advantages of transabdominal USS?
Safe
Readily available
No ionising radiation and therefore ideal for children and women of reproductive age
Disadvantages of transabdominal USS?
Difficult to obtain good images in obese patients and in patients where there is gaseous distention of bowel
Operator dependent
Difficult to produce exactly the same images every time patient attends and this means uss is not often used for assessing the response to cancer treatment
To what vessels are the ovaries in close proximity to?
External iliac vessels
What are the benefits of transvaginal scanning?
Higher frequency ultrasound, has a shorter wavelength and better spatial resolution but higher frequencies are more likely to be scattered in the body and the ultrasound transducer has to be close to the target organ
Should the bladder be empty of full for transvaginal scanning?
Empty bladder
Advantages of TVUSS?
Excellent depiction of pelvic organs
Disadvantages of TVUSS?
More invasive
Not suitable for individuals who have not been sexuallly active
Can sometimes demonstrate the tip of the iceberg and may not depict the full extend of large pelvic masses
What is an anteverted uterus?
Pointing towards bladder
Describe the different ovary volumes?
PCOS; increased
Failure; reduced
Where will fluid accumulate in a ruptured ovarian cyst when lying down?
Hepatorenal recess
When is a CT used in gynae radiology?
2nd line to acute abdo pain
Post-surgical cx; small bowel obstruction secondary to adhesions, post-op collections/ abscesses
Staging of gynae malignancy, esp ovarian and endometrial ca
Assessing response to tx in patients after chemo +/- radiology
Advantages of CT scanning?
Quick
Entire chest, abdo and pelvis can be assessed on one scan
Modern multiple detector row scanners produce very thin slices and images can be manipulated to produce coronal and sagittal reformats as well as the axial source images
Disadvantages of CT scanning?
High radiation dose with a significant dose delivered to ovaries
Used sparingly in children and patients of reproductive age
Does not provide optimal depiction of different pelvic organs (MR better at tissue resolution)
What does fat within a cyst indicate?
Dermoid cyst
Difference between T1 and T2 weighted imaging?
T1 = fat, protein and blood = bright
T2 =fat and water bright. More fluid sensitive
Advantages of MRI
Excellent depiction of pelvic organs
No ionising radiation; suitable for children and women of reproductive age
Can give idea about composition of soft tissue masses; do they contain fluid? Do thy contain fat? do they contain blood?
Can MRI be given in all stages of pregnancy?
Try to avoid 1st trim
Disadvantages of MRI?
Time consuming
Poor depiction of lungs; CT scan is query pulmonary mets
Not tolerated in claustrophobia
CI: pacemakers, heart valves, nerve stimulators, cochlear implants
For what purposes is MRI used in gynae patients?
Cancer staging
Evaluation of adnexal and uterine masses, where pelvic uss not helpful
Evaluation of patients with subfertility
MR of pituitary gland if suspected prolactinoma
What is a hydrosalpinx?
Fallopian tube blocked with fluid
Commonly post chlamydia infection
Can be seen on T2 MRI; bright white fallopian tube
How can endometriosis be diagnosed via MRI?
Deposits contain altered blood and haemaglobin degradation products
Cause characteristic MR signal changes
Altered blood - white on T1, grey on T2
Fat white on T1
What does a dermoid cyst contain?
Ovarian teratoma
Tissue derived from ectoderm, mesoderm and endoderm
FAT
For what condition is HSG utilised?
Tubal patency in those with infertility
Cervix cannulated and radiopaque contrast instilled to fill uterine cavity
What indicates a patent tube on HSG?
Contrast fills uterine cavity and then from fallopian tubes spills into the peritoneal cavity
How does ovarian cancer spread?
Disseminated by peritoneal spread
Ascites, omental and peritoneal nodules are common
Sub-diaphragmatic deposits and deposits on surface of liver are also seen
Malignant pleural effusions
How is ovarian cancer initially diagnosed?
USS
THEN CT for staging
What does is suggest if an ovarian cancer has lymph node, lung and hepatic mets?
BRAC1 mutation
What is important in cervical cancer staging?
Spread into paramtrium
Extension in vagina
Infiltration of adjacent organs; rectum, ureters, urinary bladder
Mets to regional lymph nodes (internal iliacs and obturator)
Which mode of MRI is best for staging of cervical cancer?
T2 weighted MRI
What is the best method for diagnosis of endometrial ca?
TVUSS; abnormally thickened endometrium in post-menopausal women with PMB
What is the use of MR in endometrial ca?
Assess degree of myometrial invasion
What is the use of CT in endometrial ca?
Distant nodal mets
Pulmonary mets
