Imaging in Obs & Gynae Flashcards

1
Q

what imaging methods are often used?

A

ULTRASOUND

CT

MRI

x-ray screening fluroscopy eg hysterosalpingograms (HSG)

functional imaging - PET-CT

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2
Q

what are the different indications for using radiology?

A

diagnosis of pelvic pain assessment of pelvis masses

investigation of abnormal menstrual bleeding

assessment of patients with post-menopausal bleeding

investigation of infertility

interventional radiology - fallopian tube recanalisation, uterine artery embolism etc

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3
Q

what is the most common investigation in gynaecology imaging?

A

US

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4
Q

what are the two main US techniques that are used?

A

transabdominal = scanning using a standard general abdominal US transducer

transvaginal = using a dedicated endocavity high-frequency transducer

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5
Q

why must patient have a full bladder for a transabdominal US?

A

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 US beam and degrades the image quality)

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6
Q

what are the advantages of transabdominal US?

A

safe

readily available

no ionising radiation and therefore ideal for children and women of reproductive age

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7
Q

what are the disadvantages of a transabdominal US?

A

difficult to obtain good images in obese patients and in those where there is gaseous distension of bowel

operator dependent

it is difficult to produce exactly the same images every time - therefore not often used to assessing response to cancer treatment

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8
Q

identify the bladder, endometrium and vagina on transabdominal US?

A
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9
Q

identify the left ovary on transabdominal US?

A
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10
Q

during a transvaginal US, is the patient required to have a full or empty bladder?

A

empty = a full bladder can make examination uncomfortable

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11
Q

what is the advantage of transvaginal US?

A

excellent depiction of the pelvic organs

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12
Q

what are the disadvantages of transvaginal US?

A

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)

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13
Q

identify the features of a normal transvaginal US?

A
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14
Q

identify a ruptured ovarian cyst on TVUS?

A
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15
Q

what is often used as 2nd line investigation after US in patients presenting with acute abdominal pain?

A

CT (computed tomography)

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16
Q

what types of things within obs and gynae is CT typically used for?

A

assess post-surgical complications eg small bowel obstruction secondary to adhesions, post-operative collections / abscesses etc

staging of gynaecological malignancy, especially ovarian and endometrial cancers

assessing response to treatment in patients after chemotherapy +/- radiotherapy

17
Q

what are the advantages of CT scanning?

A

quick

the entire chest abdomen 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

18
Q

what are the disadvantages of CT scanning?

A

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)

19
Q

what is the difference between MRI and CT scanning?

A

MRI uses radiofrequency energy rather than ionising radiation

20
Q

how is it possible to have MRI scans with different characteristics (eg T1 and T2 weighted scans)?

A

because it is possible to alter the time between transmitting the RF signal and receiving the RF signal from the patient

21
Q

what are the advantages of MRI scanning?

A

provides an excellent depiction of pelvic organs

no ionising radiation so can be used in children and women of reproductive age

can give some idea about the composition of soft tissue masses eg do they contain fluid, fat, blood etc

22
Q

what are the disadvantages of MRI scanning?

A

time consuming

poor deciption of lung parenchyma - a CT scan should be performed if there is query about pulmonary mets

not tolerated if patients have claustrophobia

contra-indicated in patients with pacemakers, many artificial metalic heart valves, nerve stimulators, cochlear implants etc

23
Q

what is MRI scans often used for in gynaecological patients?

A

cancer staging - esp cervical cancer

further evaluation and characterisation of adnexal and uterine masses, where pelvic US or other imaging have not provided a diagnosis

evaluation of patients with sub-fertility - are there contributory anatomical variations?

MR of the pituitary gland is perfromed in patients with suspected prolactinoma

24
Q

identify a normal MRI of female pelvis in sagittal, axial and coronal view?

A
25
Q

what abnormal finding is found on this MRI scan?

A

uterine fibroid

26
Q

what abnormality is found on these MRI scans?

A

hydrosalpinx

27
Q

endometriosis can be difficult to diagnose and patients may need diagnostic laparoscopy, but what image method may be able to diagnose it?

A

MRI

*endometriosis deposits contain altered blood and haemoglobin degradation products - these degradation products cause characteristic MR signal changes

*altered blood returns high-signal on T1 sequences (looks white) whereas it returns lower signal sequences on T2 (looks grey)

28
Q

what are dermoid cysts?

A

ovarian teratomas - contain tissue derived from ectoderm, mesoderm and endoderm and can therefore contain an admixture of many types of tissue but most contain large amounts of fat

*can be difficult to perceive on US but can be seen on MRI and CT

29
Q

what is a hysterosalpinogography (HSG) and what is it used for?

A

x ray screening procedure - real time imaging (done in 3-5 mins)

for assessment of tubal patency in patients with infertility

can also assess outline of uterine cavity - cervix is cannulated and radiopaque contrast is instilled to fill the uterine cavity

30
Q

in HSG, what is obtained just before instillation of contrast?

A

a scout “control” film

31
Q

what are the characteristics of ovarian cancer complications?

A

disseminates by peritoneal spread - ascites, omental and peritoneal nodules are common

sub-diaphragmatic deposits and deposits on the surface of the liver are also seen

malignant pleural effusions can result from spread of disease via pleuro-peritoneal communications

32
Q

for ovarian cancers, lymph nodes mets, lung mets and hepatic mets are less common and tend to be seen in patients whom disease behaviour has been modulated by chemothrapy or in cancers with what mutation?

A

BRCA1

33
Q

what imaging methods are used for initial diagnosis and radiological staging of ovarian cancer?

A

initial = US

staging = CT

34
Q

in cervical cancer, when is MRI better for imaging than CT and vice versa?

A

MRI (especially T2 weighted) is far better than CT at depiciting local disease

CT often used to determine whether or not there are distant metastases eg lung, para-aortic and mediastinal lymphadenopathy

35
Q

what is the best method of establishing abnormally thickened endometrium in patient with PMB?

A

TVUS

36
Q

in endometrial cancer, when is MRI used and when is CT used?

what is the probem with MR scanning in these patients?

A

MRI - assess degree of myometrial invasion

CT - used to loook for distant nodal metastases and pulmonary metastases

*many patients with endometrial carcinoma are obese and they may be too large for MR scanners