Imaging in Gynaecology Flashcards
what are the gynae indications for radiology
diagnosis of pelvic pain
assessment of pelvic masses
investigations of abnormal menstrual bleeding
assessment of patients with post menopausal bleeding (assess endometrial thickness)
investigating infertility (may also have MRI of pituitary and blood test for endocrinology)
interventional radiology (fallopian tube recanalisation, uterine artery embolisation)
where might USS be performed
radiology, Obs and Gynae and GP practises
what are the devices used to do transabdominal and transvaginal USS
TA- standard general abdo transducer (provides wide view of pelvis)
TV- endocavity high frequency transducer (more focused view)
what should you do before TAUSS
brief assessment of upper abdomen:
To ensure that there is no hydronephrosis
To detect early ascites
To ensure that the pelvic abnormality is not secondary to upper abdominal pathology
what must the patient do for a TAUSS
must have full bladder:
- urine distended bladder acts as an acoustic window
- a distended bladder displaces gas filled bowel loops out of the pelvis (gas scatters US beam)
what are the disadvantages of TAUSS
It is difficult to obtain good images in obese patients and in patients where there is gaseous distension of the bowel
Operator dependent
It is difficult to produce exactly the same images every time the patient attends and this means ultrasound is not often used for assessing the response to cancer treatment
what vessels are the ovaries very close to- can be seen on USS
external iliac arteries and veins
why is a transvaginal USS higher frequency
higher frequency has shorter wavelength and better spacial resolution but these are more likely to be scattered in body so transducer needs to be closer to target organs
is the bladder full or empty in a TVUSS
empty- full can be uncomfortable
what USS provides better depiction of the pelvic organs
TVUSS
what are the disadvantages of TVUSS
More invasive procedure
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 (ideally transvaginal scan should follow a transabdominal scan which allows better overview)
what does the endometrium look like on USS
in middle of uterus, is echogenic- brighter
what happens to ovarian volume in PCOS
is increased
what happens to ovarian volume in ovarian failure
is decreased
what might be seen on USS in a ruptures ovarian cysts
ascites in hepatorenal recess
small haematoma next to ovary
when is CT used in gynae
2nd line after ISS in acute abdo pain
to asses post surgical complications - small bowel obstruction due to adhesions, post op collections/ abscesses
staging of gynae malignancy- esp ovarian and endometrial cancers
assessing response to treatment in patients after chemo +/- radio
what are the disadvantaged of CT in gynae
High radiation dose (equivalent to about 160 chest x-rays) with a 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)
what is diagnostic of a dermoid cyst
if it contains fat
what is bright on T1 MRIs
fat, protein, blood
what is bright on T2 MRIs
water
what are the advantages of MRI
excellent depiction of pelvic organs
No ionising radiation and is therefore 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 ?
is MRI safe in pregnancy
yes except in first trimester
what does MRI provide poor depiction of
lung parenchyma – a CT scan should be performed if there is query about pulmonary metastases
when is MRI used in gynae
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
what is the junctional zone
area between myo and endometrium
what is a hydrosalpinx usually caused by
previous chlamydia infection
what Ix can be used to diagnose endometriosis
laparoscopy
MRI
what can b suppressed on T1 weight MRIs
fat
what does endometriosis look like on MRI
Endometriosis deposits contain altered blood and haemoglobin degradation products
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
ovarian teratomas
what do dermoid cysts contain
tissue derived from ectoderm, mesoderm and endoderm. They can therefore contain an admixture of many types of tissue, but most contain a large amount of fat.
what Ix is best to see fat
Fat, when admixed with other tissues, can be difficult to perceive on ultrasound, but has predictable MR signal characteristics (T1, T1 fat suppression) and can also be diagnosed on CT
what happens to fat on T1 fat suppression scan
goes dark
what is hysterosalpingography
x ray with contrast
- Cervix is cannulated and radiopaque contrast instilled to fill the uterine cavity
- Just before instillation of contrast, a scout ‘control’ film is obtained
- Once contrast instilled, a series of images are captured as the contrast fills uterine cavity, then into fallopian tubes and spills into peritoneal cavity
- completed in 3-5 mins
what is HSG used to assess
tubal patency in infertility
outline of uterine cavity
why are pre cancer treatment scans important
serves as a “baseline” study so that subsequent scans can be used to assess response to treatment (chemotherapy, radiotherapy etc)
how are gynae cancers staged
TNM
how does ovarian cancer disseminate
peritoneal spread
where does ovarian cancer commonly spread
Sub-diaphragmatic deposits
omental and peritoneal nodules
Lymph node metastases, lung metastases and hepatic metastases are less common and tend to be seen in patients in whom the disease behaviour has been modulated by chemotherapy or in cancers with the BRCA1 mutation
how can ovarian cancer present
Ascites
Malignant pleural effusions can result from spread of disease via pleuro-peritoneal communications
what Ix for ovarian cancer
Initial diagnosis is often made by ultrasound (ovarian masses)
CT scanning for radiological staging
what is important in the staging of cervical cancer
determining whether there is;
Spread into the parametrium (tissue adjacent to cervix on either side)
Extension into the vagina
Infiltration of adjacent organs: rectum, ureters, urinary bladder
Metastases to regional lymph nodes (internal iliac and obturator)
what scan for staging of cervical cancer
MR (especially T2-weighted sequences) is far better than CT at depicting local disease, but CT is often used to determine whether or not there are distant metastases – e.g. lung, para-aortic and mediastinal lymphadenopathy
what is the best method of establishing abnormally thickened endometrium in a post-menopausal patient with PMB
TVUSS
what Ix for endometrial cancer staging
CT to look for distal node and pulmonary mets
MRI can assess myometrial invasion
what is the problems with patients who have endometrial cancer
many are very obese, too large for MR scanners
