Week 3 - I - Imaging in Gynaecology - ultrasound, CT, MRI, hydrosalpingography

Question 1

What is the most common investigation in gynaecology imaging, and is of course used in ante-natal practice?

Answer 1

This is ultrasound

Question 2

What are two main advantages of ultrasound?

Answer 2

It is cheap and relatively safe as there is no ionising radiation

Question 3

What are the two main types of ultrasound scanning?

Answer 3

Transabdominal ultrasound scan Transvaginal ultrasound scan

Question 4

What is the difference in transducers used in transabdominal and transvaginal ultrasound scans?

Answer 4

Transabdominal scan - standard general US abdominal transducer Transvaginal - this uses a deidcated endocavity high frequency transducer

Question 5

In a transabdominal ultrasound scan, the pelvic organs are are scaned through the anterior abdominal wall Should the bladder be full or empty in this scan? (should it be full or empty in transvaginal)

Answer 5

The bladder should be full in a transabdominal ultrasound scan - The urine-distended bladder acts as an “acoustic window” A distended bladder displaces gas-filled bowel loops out of the pelvis (bowel gas scatters the ultrasound beam and degrades image quality) In a trranvaginal ultrasound scan - the bladder should be empty

Question 6

Why is it important that the patient must have a full bladder on transabdominal ultrasound scan? Why is important that the bladder should be empty on transvaginal?

Answer 6

On transabdominal - a full bladder acts as an acoustic window - it displaces gas-filled bowel loops out of the pelvis - bowel gas can scatter the ultrasound beam and degrade image quality Empty bladder is important as a full bladder can be uncomfortable on transvaginal

Question 7

What type of patients is transabdominal not great in? What are its advantages? Why is it not used in the staging of cancer treatment?

Answer 7

Advantages - * safe, ready to use, and no ionising radiatio so safe for children and women of reproductive age Disadvantages - * It is difficult to obtain good images in obese patients and in patients where there is gaseous distension of the bowel * Also operator dependent Not used in the staging of cancer as difficult to produce exactly the same images every time a patient attends

Question 8

What type of thing is usually anechoic on ultrasound? Give example of an anechioic organ?

Answer 8

Fluid filled structures

Full bladder is anechoic - fluid is black on ultrasound

Question 9

Transvaginal ultrasound scan has a dedicated endocavity high frequency transducer Higher frequency ultrasound has a shorter wavelength and better spatial resolution, but what is the risk?

Answer 9

Higher freuqncies are more likely to be scattered in the body and the transducer needs to be held close to the target organ Transvaginal scanning is used so that the ultrasound probe is as close as possible to the pelvic organs

Question 10

TVUS or TAUS require a full bladder and why?

Answer 10

TAUS - requires a full bladder - urine distended bladder acts as an acoustic window - the distended bladder displaces gas-filled bowl loops out of the pelvis (bowel gas scatters the ultrasound beam and degrades image quality) TVUS - empty bladder as it can be uncomfortable for the patient

Question 11

What is the main advantage of the transvaginal ultrasound scan?

Answer 11

Excellent depiction of pelvic organs

Question 12

What are the disadvantages of TVUS? What should be carried out first, TVUSorTAUS? Can see the ovarian follicles on image

Answer 12

Disadvamtages are it is more invasive

Also not suitbale for indicvudals who have not been sexually active

• TAUS may only present tip of the iceberg of pelvic masses and therefore TVUS ideally should be carried out after TAUS

Question 13

There was an abnormal mass on TAUS and therefore a TVUS was carried out What does the TVUS show?

Answer 13

This shows a ruptured ovarian cyst - fluid is black on ultrasound

Question 14

In patients presenting with acute abdominal pain, what is often second line to the ultrasound?

Answer 14

A CT scan

Question 15

CT scanning ADVANTAGES * Quick * The entire chest abdomen and pelvis can be assessed on one scan * Modern multiple detector row (“multislice”) scanners produce very thin slices and images can be manipulated to produce coronal and sagittal reformats, as well as the axial source images What are the disadvantages of CT scanning?

Answer 15

There is a high radiation dose (equivalent to about 160 Xrays) - therefore used sparingly in children and women of reproductive age Doesnt show optimal reflection of different pelvic organs - MR is better for soft tissue structures

Question 16

What are the advantages of CT scanning vs the advantages of MRI scanning?

Answer 16

CT scanning * Quick and the entire chest and pelvis can be assessed in one scan * Provides multiple images (multislice) so can change the plane of the scan MRI scanning * Provides an excellent depection of the pelvic organs unlike CT * Doesnt use ionising radiation, therefore can be used for children and women of reproductive age

Question 17

MRI scans can also give some idea about the composition of soft tissue masses – e.g. do they contain fluid, fat, blood etc ? What are some disadvantages about using this scanning method? (remember metastases)

Answer 17

It is time consuming and poor for lung parenchyma so pulmonary metastases should use CT scan instead Also not tolerated well in patients with claustrophobia or metal stuff

Question 18

Both MRI and CT scans are good for use in cancer staging What cancer staging is CT used more in? What cancer staging is MRI used especially in?

Answer 18

CT scans - great for ovarian and endometrial cancer staging MRI - great for cervical cancer staging

Question 19

In patients with suspected prolactinoma as the cause of sub-fertility, what scan is carried out?

Answer 19

MRI scan of pituitary gland is carried out

Question 20

Which structures are each of the arrows pointing to?

Answer 20

Blue area - pubic symphysis (bone is black on MRI)

Red arrow - Bladder

Green arrow - anteverted uterus

Question 21

Hematometra develops when the uterus becomes distended with blood secondary to obstruction or atresia of the lower reproductive tract—the uterus, cervix or vagina—which would otherwise provide an outflow for menstrual blood.. It is most commonly caused by an imperforate hymen What can this shed uterine blood collection cause?

Answer 21

This can cause endometriosis when the blood flows elsewhere ie fallopian tubes - These displaced endometrial cells stick to the pelvic walls and surfaces of pelvic organs, where they grow and continue to thicken and bleed over the course of each menstrual cycle.

Question 22

Endometriosis can be difficult to diagnose and patients may need diagnostic laparoscopy Endometriosis deposits contain altered blood and haemoglobin degradation products. In the appropriate clincial contet, what scan can be used to diagnose endometriosis? (usually laproscopy - allows surgeon to look inside (keyhole) is used though)

Answer 22

MI scan can be used in the right context to diagnose endometriosis- Endometriosis deposits contain altered blood and haemoglobin degradation products. These degradation products cause characteristic MR signal changes

Question 23

These cysts/tumours 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 is this type of tumour known as?

Answer 23

This is a dermoid cyst - ovarian teratoma

Question 24

Dermoid cyst Fat, when admixed with other tissues, can be difficult to perceive on ultrasound, but has predictable MR signal characteristics and can also be diagnosed on CT What is used to measure teratoma with yolk sac elements and what for highly malignant teratoma containing trophoblastic tissue?

Answer 24

Teratoma containing yolk sac elements - measure alfa fetoprotein (AFP) Teratoma containing trophoblastic tissue - Human chorionic gonadotrophin (HCG)

Question 25

What imaging investigation is used to assess tubal patency in patients with infertility?

Answer 25

Hysterosalpingography (HSG) - treal time xray showing the progression of dyeOnce contrast instilled, a series of images are captured as the contrast fills uterine cavity, then into fallopian tubes and spills into peritoneal cavity

Question 26

How is hysterosalpingography carried out?

Normal hysterosalpingogram picture - smooth triangular uterine cavity and spill from both tubes The bones of the pelvis are seen on the x-ray around edges of image

Answer 26

Radiographic contrasts (Dye) is injected into the uterine cavity via the vagina and cervix

The uterine cavity fills with ye and if the fallopian tubes are open, the dye will pass into them and spill into the peritoneal cavity at the other end

The HSG makes sure the fallopian tubes are patent the uterine end (proximal) and the ovarian end (distal)

Question 27

The HSG procedure usually takes 3-5 minutes to complete and is therefore quick What is seen in this picture?

Answer 27

A normal triangular shaped uterus is seen However distal ends of the right and left fallopian tubes are not patent (hydrosaplinx - distally blocked fallopian tube filled with serous or clear fluid) therefore this patient is infertile Can treat with IVF

Question 28

Cancers are staged using the TNM (Tumour Nodes Metastases) classification Staging plays an important role in treatment planning and can assist in discussions about the patient’s prognosis How does ovarian cancer usually disseminate?

Answer 28

Tends to disseminate by peritoneal spread - ascites is a common symptom

Question 29

Ovarian cancers 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 is initial disgnosis often made for ovarian cancers? What is used for radiological staging?

Answer 29

Initial diagnoses often made by ultrasound and CT is used to stage the tumour

Question 30

When staging cervical cancer, it is important to determine whether there is: Spread into the parametrium Extension into the vagina Infiltration of adjacent organs: rectum, ureters, urinary bladder Metastases to regional lymph nodes (internal iliac and obturator) What is the parametrium? What is better for depicting local disease and metastases?

Answer 30

Parametrium is the fibrous tissue separating the supravaginal portion of the cervix from the bladder

• MR scan is better for depicting local disease
• CT is better for looking for distant metastases

Question 31

The cervical cancer tumour is blocking the cervical canal hear What ca be seen in the uterus?

Answer 31

Can see hydrometra of the uterus - Hydrometra is a descriptive term that refers to a distended uterus filled with clear, non-infected fluid. Hematometra or hemometra is a medical condition involving collection or retention of blood in the uterus.

Question 32

Endometrial cancers usually present in post menopausal women who have bleeding What is the best method of establishing abnormally thickened endometrium ? What is used for looking for distant metastases in endometrial cancer?

Answer 32

This would be transvaginal ultrasound scanning MR scanning can be used to assess the degree of myometrial invasion but CT scanning is used to look for distant nodal metastases and pulmonary metastases Many patients with endometrial carcinoma are obese, and they may be too large for the narrow bore of MR scanners