Imaging Flashcards
What imaging methods are used in obs & gynae?
USS CT MRI X-ray screning fluoroscopy e.g. hysterosalpimgograms (HSG) Functional imaging (PET-CT)
What are indications for radiology?
Pelvic pain/masses Abnormal menstrual bleeding Post menopausal bleeding Infertility Fallopian tube recanulisation Urinary artery embolism etc
What imaging technique is the most common, and why?
USS
Cheap
Safe
Can be used in clinic
What are the 2 main ultrasound techniques used?
Transabdominal
Transvaginal
Describe transabdominal USS
Scanning using a standard general abdominal US transducer
Describe transvaginal USS
Scanning using a dedicated endocavity high-frequency transucer
Why should you USS the upper abdomen briefly when doing an obs&gynae USS?
Check for hydronephrosis
Early ascites
CHeck the pelvic issue isn’t secondary to a upper abdo pathology
Why must the patient have a full bladder?
The urine-distended bladder acts as an “acoustic window”
Displaces gas-filled loops of bowel out of the pelvis
What are the advantages of doing an USS?
Safe
Readily available
No ionising radiation
What are the disadvantages of an USS?
Difficult to obtain good images in obese patients and those with gaseous bowel distension
Operator dependant
Hard to produce same image every time so not good at assessing the response to cancer treatment
Describe the waves of a higher frequency
Shorter wavelengths
Better spatial resolution
What is bad about using a higher frequency?
Need to be closer target organ
What is needed for a transvaginal USS?
An empty bladder
What is an advantage of Transvaginal scanning?
Excellent depiction of the pelvic organs
What are some disadvantages of transvaginal screening?
More invasive
Not suitable for patients who have not been sexually active
May not depict the whole issue
When is a CT scan usually used?
2nd line to an USS when patient demonstrates pain
What can a CT be good for?
Assess post-surgical complications
Staging of malignancy
Assessing response to treatments
What are advantages of CT?
Quick
entire chest, abdo and pelvis can be seen in one scan
Multiple coronal and sagittal pics
What are some disadvantages of CT?
High radiation
Doesn’t provide optimal depiction of different pelvic organs
What are advantages to MRI?
Provides an excellent depiction of pelvic organs
No ionising radiation
Can give info on soft tissue masses
What are disadvantages of MRI?
Time-consuming
Poor depiction of lung paranchyma
Not tolerated if patients have claustorphobia
Contra-indicated in patients with pacemakers, many artificial heart valves, nerve stimulators, cochlear implants etc.
When can MRI be useful in obs&gynae patients?
Cancer staging
Further evaluation and characterisation of adnexal and uterine masses
Sub-fertility evaluation
MRI of pituitary gland is performed in patients with suspected prolactinoma
What do endometriosis deposits contain?
Altered blood and haemoglobin degradation products
What type of scan is better to see endometriosis?
T1 sequences
What do dermoid cysts contain? (Ovarian teratomas)
Tissue derived from the ectoderm and fat
What is a Hysterosalpingogaphy (HSG)?
X-ray screening procedure
Assessment for tubal patency in infertility
Outline uterine cavity
How long does a HSG take?
3-5 mins
What is done in a HSG?
Cervix is cannulated and radioopaque contrast instilled to fill the uterine cavity
In cancer staging, what does TNM stand for?
Tumour
Nodes
Metastases
How does ovarian cancer disseminate?
peritoneal spread
What is important to find out regarding cervical cancer?
Spread to parametrium?
Extension into vagina?
infiltration of adjacent organs?
Metastases to regional lymph nodes?
What is best imaging for depicting local disease?
MRI (T2)
What is the best method for looking at endometrial cancer?
Transvaginal USS
What use to MRI and CT have in endometrial cancer?
MRI - assess degree of myometrial invasion
CT - Look for distant nodal metastases and pulmonary mets
What are many endometrial cancer patients?
Obese
