Imaging in Gynaecology Flashcards
What imaging modalities are used in gynaecology?
US, CT, MRI, fluoroscopy (HSG), PET-CT
What are the indications for using radiology?
Diagnosis of pelvic pain Assessment of pelvic pain Investigation of abnormal menstrual bleeding Assessment of postmenopausal bleeding Investigation of infertility Interventional radiology
Where can US be performed?
Radiology department, gynaecology clinic and some GP practices
What are the two types of US used?
Transabdominal and transvaginal
How are pelvic organs scanned during a transabdominal US?
Through the anterior pelvic wall
Should the upper abdomen be looked at during a transabdominal US?
Yes = look for hydronephrosis, ascites or primary abdominal pathology
What preparation is needed for a transabdominal US?
Need a full bladder = urine-distended bladder acts as acoustic window
What are the advantages of transabdominal US?
Safe, readily available, no ionising radiation
What are the disadvantages of transabdominal US?
Difficult to image obese patients and if there is gaseous bowel
Difficult to produce exactly the same image every time
What are some features of transvaginal US?
Higher frequency so shorter wavelength and better spatial resolution but needs to be close to target as more likely to scatter
How should the bladder be prepared for a transvaginal US?
Requires empty bladder = uncomfortable if the bladder is full
What are the advantages of a transvaginal US?
Excellent depiction of pelvic organs
What are the disadvantages of a transvaginal US?
Invasive, not suitable for those who haven’t had sex, may not depict full extent of large pelvic masses
What are CT scans used for as a second line investigation?
Often used as second line investigation after US in patients with acute abdominal pain
What are some uses of CT in gynaecology?
Can be used to assess post-surgical complications
Useful for staging malignancy (endometrial, ovarian)
Can assess response to treatment after chemotherapy +/- radiotherapy
What are the advantages of CT?
Quick, entire chest/abdomen/pelvis can be assessed in one image, can manipulate images to give many different views
What are the disadvantages of CT?
High radiation dose, doesn’t provide optimal depiction of different pelvic organs
How does MRI create images?
Uses radiofrequency energy rather than ionising radiation = different protocols can be used to define tissue composition in the area being scanned
What are the advantages of MRI?
Provides excellent depiction of pelvic organs, no ionising radiation, can give some idea about composition of soft tissue masses
What are the disadvantages of MRI?
Time consuming, poor depiction of lung parenchyma, not suitable if claustrophobic
What are the contraindications of MRI?
Pacemaker, artificial metal heart valves, nerve stimulators, cochlear implants
What are the gynaecological uses of MRI?
Cancer staging = especially cervical
Evaluation of adnexal and uterine masses
Evaluation of patients with subfertility
MRI of pituitary for suspected prolactinoma
How is endometriosis diagnosed?
Difficult to diagnose = patients may need diagnostic laparoscopy
How is endometriosis recognised on MRI?
Deposits contain altered blood and haemoglobin degradation products = cause characteristic MRI changes
How does the altered blood in endometriosis appear on MRI?
Returns high signal on T1 sequences = looks white
Returns low signal on T2 sequences = looks grey
How does fat appear on MRI?
Looks white on T1 sequences but appears dark on special fat-suppression sequences
What do dermoid cysts contain?
Tissue derived from ectoderm, mesoderm and endoderm = mostly contain fat v=but can contain many types of tissue
How is fat imaged?
Has predictable MRI signal characteristics and can also use CT, but difficult to perceive on US
What is a hysterosalpingography (HSG)?
X-ray screening procedure = real-time imaging, usually takes 3-5mins
What is an HSG used for?
Assessment of tubal patency in suspected infertility and assessment of uterine cavity
How is an HSG carried out?
Cervix cannulated and radiopaque contrast instilled to fill uterine cavity
What is done before contrast is instilled during an HSG?
A scout “control” film is obtained just before
When are images captured during an HSG?
Once contrast is instilled = series of images captured as contrast fills uterine cavity, then into fallopian tubes and spills into peritoneal cavity
How is cancer staged?
Using TMN system
What is the purpose of the pre-treatment scan for cancer?
Serves as baseline so subsequent scans can be used to assess treatment response
How does ovarian cancer spread?
Disseminates by peritoneal spread
What extra-ovarian features are common in ovarian cancer?
Ascites, omental and peritoneal nodules are common
How do malignant pleural effusions occur in ovarian cancer?
Result from spread of disease via pleuro-peritoneal communications
Are lymph node, lung and liver metastases common in ovarian cancer?
No = tend to be seen in patients in whom disease behaviour has been modulated by chemo or in cancers with BRCA1 mutation
How is the initial diagnosis of ovarian cancer made?
Using US
How is ovarian cancer staged?
CT usually used for radiological staging
What must be determined when when staging cervical cancer?
Presence of = spread into parametrium, extensions into vagina, infiltration of adjacent organs, metastases to regional lymph nodes
What is used for imaging cervical cancer?
MRI (esp T2) is better than CT for local disease
CT used for determining presence of distant metastases
What modality is best for diagnosing endometrial cancer?
Transvaginal US = best for establishing abnormally thickened endometrium
What are MRI scans used for in endometrial cancer?
Assessing degree of myometrial invasion
Why is there difficulty using MRI to image endometrial cancer?
Many patients obese so are too large for narrow MRI bore
What are CT scans used for in endometrial cancer?
Used to find distant metastases and pulmonary metastases
