Obestetric

Question 1

15. Regarding molar pregnancy ultrasound:

A. High velocity, low impedance waveforms on Doppler occur for later in a molar pregnancy than in a normal pregnancy

B. The uterine artery Pulsatility Index (PI) is proportional to arterovenous shunting

C. Patients with a low P1 are more likely to become resistant to single drug therapy with methotrexate

D. Low impedance waveforms with high diastolic velocities are fndings in a normal pregnancy

E. A minimum normal UAPI is 2.5

Answer 1

C. Patients with a low P1 are more likely to become resistant to single drug therapy with methotrexate

Minimal normal UAPI > 1.5. High velocity low impedance waveforms on Doppler are fndings in a normal pregnancy but are found in the frst and second trimesters in molar pregnancy (far earlier than in a normal pregnancy). Low P1 indicate increased AV shunting and are more likely to become resistant to single drug therapy with methotrexate.

Question 2

6. At the 20-week fetal anomaly ultrasound scan, the cervix of a 25-year-old primagravida is measured to be 22 mm long. She is most likely to have been treated with which of the following?

a. oestrogens

b. progestogens

c. heparin

d. salbutamol

e. corticosteroids

Answer 2

a. oestrogens

Uterine cervix length can be measured transabdominally or transvaginally. With the former approach, the measurement can be 10% greater than the corresponding transvaginal measurement, because, while the full urinary bladder is a desirable acoustic window, it increases the cervical length. Transvaginally, the normal cervical length is 40+8mm in the first 14 weeks of pregnancy, 42+10mm in the second trimester and 32+12mm from 28 weeks on. An incompetent cervix usually develops during the second or early third trimester. Incidence isincreased after cervical trauma, diethylstilbestrol exposure (cervical hypoplasia), and oestrogen treatment. On imaging, dilatation of the cervical canal is seen to begin at the internal os and extend out. It produces a beaking or funnelling appearance and shortens the cervical canal to less than 25mm. Clinically, the membranes or even fetal parts may be seen through the external os.

Question 3

11) A 30-year-old woman attends for a first-trimester ultrasound scan. Her last menstrual period was approximately 10 weeks prior to the scan, but she is unsure of the exact dates. What is the most accurate ultrasound measurement for dating the pregnancy at this stage?

a. biparietal diameter

b. mean gestational sac diameter

c. crown–rump length

d. femur length

e. abdominal circumference

Answer 3

c. crown–rump length

Estimation of gestational age is most accurate in the first trimester.

The crown–rump length is used, which has a range of +0.7 weeks. Beyond about 13 weeks, the measurement becomes less reliable as the fetus becomes increasingly flexed.

In the very early first trimester, the mean gestational sac diameter can be used to estimate gestation age with similar accuracy, but this measurement should not be used once the embryo can be seen.

Biparietal diameter (or alternatively head circumference) becomes the most reliable measurement in the second trimester with an accuracy of +1.2 weeks up to 20 weeks.

Femur length is less precise. Abdominal circumference is the least accurate measurement, and is generally used only to assess fetal growth and proportionality.

Estimation of gestational age becomes considerably less reliable with advancing pregnancy; beyond about 22 weeks, fetal growth becomes the main determinant of fetal size.

Question 4

29) Endoanal ultrasound scan is performed on a 20-week pregnant patient who sustained perineal damage during a previous vaginal delivery, to guide the method of delivery. Scarring is seen involving more than 50% of the external sphincter, but the internal anal sphincter is intact. Which of the following best represents the degree of perineal injury?

a. first

b. second

c. third Ba)

d. third Bb)

e. third Bc)

Answer 4

d. third Bb)

First-degree perineal tear involves skin only.

Perineal muscle is torn in a second-degree tear and so includes episiotomy.

Anal sphincter damage defines third-degree injury, this being subdivided into

types 3a, involving less than 50% of external sphincter,

3b, more than 50% of external sphincter,

and 3c, when the internal sphincter is torn.

A tear extending into the anal epithelium is a fourth-degree tear.

Question 5

42) A 23-year-old woman is found on a 10-week dating ultrasound scan to have a twin pregnancy. A repeat examination prompted by blood spotting per vaginum, later attributed to a cervical erosion, shows a singleton pregnancy and no evidence of the twin. What should this be termed?

a. foetus papyraceus

b. vanishing twin

c. fetal death in utero

d. immune fetal hydrops

e. non-immune fetal hydrops

Answer 5

b. vanishing twin

‘Vanishing twin’ occurs at less than 13 weeks when one twin is completely resorbed with no residuum evident on ultrasound scan.

In foetus papyraceus, one twin is compressed and seen plastered to the adjacent membranes.

Fetal death in utero or intrauterine death is signalled by absent heart and somatic movement in the second and third trimesters.

Hydrops is excess total body water manifested as extracellular liquid accumulation in tissues and serous cavities.

In hydrops of immune orgin, antibodies to red blood cells are present.

Question 6

52) On the 20-week fetal anomaly scan, it is noticed that there is less than 1 mm of hypoechoic myometrium between placenta and echo-bright uterine serosa. An MRI is performed. On T2W images, the placenta is heterogeneous and bright, and causes junctional zone interruption and marked focal myometrial thinning. The serosa looks intact. These findings describe which of the following?

a. placenta accreta

b. placenta increta

c. placenta percreta

d. placenta praevia

e. placental abruption

Answer 6

b. placenta increta

The normal decidua forms a barrier between chorionic villi and uterus, preventing deep invasion of placental material.

An underdeveloped or absent decidua permits direct contact of chorionic villi with the myometrium, known as placenta accreta.

When the villi invade the myometrium, it becomes placenta increta; if the serosa is penetrated, it is placenta percreta.

Diagnosis is difficult on ultrasound scan, but MRI can help.

Risk factors are previous caesarean section and myomectomy, multiparity and increasing maternal age.

Complications include maternal haemorrhage, premature delivery, intrauterine growth retardation and 5% chance of perinatal death.

To protect the mother, balloon catheters can be placed over the internal iliac arteries prior to caesarean delivery

Question 7

54) During a 20-week fetal anomaly scan, it is noticed that the umbilical cord has only two vessels. Which of the following conditions is most frequently associated with this finding?

a. triploidy

b. Turner’s syndrome

c. trisomy 18

d. trisomy 13

e. Down’s syndrome

Answer 7

c. trisomy 18

In 67% of cases of single umbilical artery, there are chromosomal abnormalities.

Trisomy 18 has a stronger association than trisomy 13, Turner’s syndrome or triploidy.

Down’s syndrome is not associated.

Question 8

56) During the third trimester of pregnancy, a multiparous, 48-year-old woman who is a smoker experiences bleeding per vaginum. Ultrasound scan shows the edge of the placenta to cover the whole of the internal cervical os. It is decided that delivery will be by caesarean section, for which of the following reasons?

a. placental separation

b. low-lying placenta

c. marginal placenta praevia

d. complete placenta praevia

e. placental abruption

Answer 8

d. complete placenta praevia

This occurs in 1 in 200 pregnancies, and the incidence rises with increasing maternal age, multiparity, smoking and previous caesarean section. Delivery is by caesarean section. Third-trimester bleeding occurs in 90% of cases of placenta praevia, with premature delivery and perinatal and maternal death as other complications.

A low-lying placenta is one within 2cm of the internal cervical os.

Marginal placenta praevia describes a placental edge up to the os.

Partial praevia covers some of the os.

From 60% to 90% of patients with placenta praevia in the second trimester have a normal placenta by term because of differential growth of the lower uterine segment.

Question 9

58) A 28-week pregnant patient known to have uterine fibroids reports abdominal pain for the preceding 4 weeks. On questioning she admits to small amounts of brown/red vaginal loss. Ultrasound scan shows a complex but predominantly hypoechoic collection between the uterine wall and placenta. Which of the following is the most likely explanation for the imaging findings?

a. acute placental abruption

b. placental abruption 1 week previously

c. placental abruption 4 weeks previously

d. placenta membranacea

e. ectopic pregnancy

Answer 9

b. placental abruption 1 week previously

Abruption can be regarded as premature separation of the placenta from the uterine wall secondary to maternal haemorrhage after 20 weeks’ gestation.

Manifestations include vaginal bleeding, pain and disseminated intravascular coagulation.

Risk factors include hypertension (pre-eclampsia), previous abruption, smoking, cocaine, leiomyoma, idiopathic factors, fetal malformation and trauma.

Placental abruption is responsible for 15–25% of perinatal deaths.

On ultrasound scan, acute haemorrhage appears hyperechoic or isoechoic, and may be difficult to distinguish from the adjacent placenta.

The haematoma forms a complex hypoechoic collection within 1 week of abruption, and usually appears as an anechoic collection within 2 weeks.

Placenta membranacea refers to the presence of placental villi in the peripheral membranes.

Question 10

66) In antenatal ultrasound scanning, which of the following is a major marker associated with trisomy 21?

a. echogenic bowel before 20 weeks

b. echogenic intracardiac focus

c. brachycephaly

d. small cerebellum

e. hydrothorax

Answer 10

e. hydrothorax

Major markers for Down’s syndrome include ventriculoseptal defect, cystic hygroma, omphalocele, duodenal atresia, hydrothorax, mild cerebral ventricular dilatation, corpus callosum agenesis and imperforate anus.

The other options given are minor markers

Question 11

67) In a twin pregnancy, entanglement of the umbilical cords is discovered. Which of the following best describes the genetic and anatomical relationship of the twins?

a. dizygotic; both intrauterine

b. monozygotic; dichorionic diamniotic

c. monozygotic; monochorionic diamniotic

d. monozygotic; monochorionic monoamniotic

e. dizygotic; one ectopic

Answer 11

d. monozygotic; monochorionic monoamniotic

For cord entanglement, the twins must be in the same amniotic sac. Dizygotic twins are non-identical and result from fertilization of two separate ova

Question 12

80) A 25-year-old woman with pelvic inflammatory disease has a raised serum b-hCG level. Ultrasound scan reveals an empty uterine cavity and an extrauterine amniotic sac. MRI some weeks later shows circumferential bowel involvement by the placenta, which appears to be continuous with the bowel wall muscle. Which of the following is the most compelling reason for a further follow-up MRI?

a. to check that the placenta has been fully removed by surgery

b. to check for response to chemotherapy

c. to ensure that the placenta involutes following delivery and no abscess has developed

d. to stage the gestational trophoblastic neoplasia

e. to date the pregnancy

Answer 12

c. to ensure that the placenta involutes following delivery and no abscess has developed

The history and imaging features are of extrauterine abdominal pregnancy, which occurs when the fertilized ovum implants directly on the peritoneal surface of the abdomen. This is more likely when the prevalence of pelvic inflammatory disease and ectopic pregnancy is higher. The diagnosis is often established with ultrasound scan. MRI can be used to identify the location and assess adherence to abdominal viscera by the placenta. MR angiography can suggest feeding arteries. MRI at this stage also has a role in detecting fetal anomalies. If the placenta is adherent to abdominal viscera, it is not removed, because this could precipitate catastrophic arterial haemorrhage. Therefore, MRI is performed later to ensure involution of the placenta and exclude abscess formation. Placental adherence is suggested on MRI when it is contiguous with liver or spleen parenchyma, shows circumferential involvement of bowel or shows continuity with muscle of bowel wall

Question 13

100) On the third day postpartum, a 25-year-old female develops rightsided lower abdominal pain and breathlessness. CT pulmonary angiogram confirms a pulmonary embolus. Bilateral leg Doppler scan is normal. Which of the following diagnoses requires the most serious consideration?

a. appendicitis

b. right ovarian vein thrombosis

c. torsion of ovarian cyst

d. broad ligament haematoma

e. pelvic abscess

Answer 13

b. right ovarian vein thrombosis

The puerperium is a hypercoagulable state, and puerperal endometritis can seed bacteria along the ovarian vein. Eighty per cent of thromboses are on the right and 14% are bilateral. Incidence is between 1 in 600 and 1 in 2000 deliveries.

On contrast-enhanced CT, a tubular structure with low-density centre and peripheral enhancement is seen. Complications include inferior vena caval thrombosis, pulmonary embolus (25%), septicaemia, metastatic abscess formation and death (5%)

Question 14

93) A 45 year old who is assumed to be pregnant presents with a uterus large for dates and hyperemesis gravidarum. The b-hCG levels are raised. Transvaginal ultrasound scan shows hyperechoic soft tissue with cysts filling the uterine cavity and a septated large left ovarian cyst. Which of the following additional features favours the diagnosis of complete hydatidiform mole as opposed to any other gestational trophoblastic disease?

a. no fetal parts

b. dysmorphic fetus

c. associated prominent vessels

d. pelvic lymph node involvement

e. lung metastases

Answer 14

a. no fetal parts

Gestational trophoblastic disease (GTD) is abnormal proliferation of the trophoblast, which can give rise to a complete or partial hydatidiform mole, invasive mole or choriocarcinoma.

Increasing age and previous GTD are risk factors.

Elevation of b-hCG aids diagnosis and is of value in assessing risk of metastatic disease (hence prognosis), and can be used to assess treatment response or detect recurrence.

Complete moles have a higher malignant potential than partial moles.

A complete mole has no fetal parts and has a 46,XX or, less often, a 46,XY karyotype.

A partial mole has fetal parts and a triploid karyotype with 69 chromosomes.

Eighty per cent of hydatidiform moles resolve with evacuation, 15% are locally invasive and 5% give rise to metastatic choriocarcinoma.

When GTD is staged, there are no ‘regional’ nodes, and any nodal spread is considered metastatic with a significant worsening of prognosis.

On ultrasound, the mole is echogenic but with a vesicular appearance.

Fifty per cent of cases are associated with a large, septated theca lutein cyst.

On Doppler ultrasound scan, they have prominent associated vessels with low resistance and high peak systolic velocity.

Question 15

29 A 6 week pregnant lady presents to the early pregnancy unit with PV bleeding. As part of the US examination, crown-rump length (CRL) and mean gestational sac diameter (MGSD) measurements are recorded. Which of the following is not correct?

(a) Lack of detectable cardiac activity in a 8 mm CRL embryo is normal

(b) MGSD of 25 mm on transabdominal US should have adetectable embryo

(c) MGSD of 20 mm on transabdominal US should have a detectable yolk sac

(d) MGSD of 20 mm on transvaginal US should have both detectable yolk sac and embryo

(e) Cardiac activity may be detected in embryos with a CRL as small as 2 mm

Answer 15

(a) Lack of detectable cardiac activity in a 8 mm CRL embryo is normal

The discriminatory level of CRL before lack of cardiac activity becomes abnormal is 6 mm. MGSD is defined as (length +width + height)/3.

Question 16

20 A 28 year old lady presents with PV bleeding and rightsided lower abdominal pain. Serum B-HCG is elevated. Transabdominal US does not show an intrauterine pregnancy. What is the likeliest site of an ectopic pregnancy?

(a) Right ovary

(b) Tubal ampulla

(c) Tubal isthmus

(d) Pouch of Douglas

(e) Cervix

Answer 16

(b) Tubal ampulla

95% of ectopic pregnancies are tubal, with ampullary pregnancies accounting for 80% of these. Abdominal, ovarian, and cervicalpregnancies are extremely rare. In 5% of cases the pelvic US is normal.

Question 17

39 A 23 year old woman presents with abdominal pain. Her B-HCG test is positive and her LMP was 6 weeks ago. An US scan is arranged. Which of the following features suggest a pseudogestational sac rather than a true gestational sac?

(a) A well defined complete decidual reaction of greater than 2 mm

(b) Location of the lesion within the fundus

(c) A round or oval appearance

(d) The lack of a double decidual sign

(e) Eccentricity of the lesion relative to the endometrium

Answer 17

(d) The lack of a double decidual sign

The double decidual sign is useful in determining a true gestational sac particularly after 5 weeks gestation. It comprises two hyperechoic rings separated by the hypoechoic apposed endometrial walls. It has a PPV for pregnancy of 98%.

Question 18

@# 45 During a routine antenatal ultrasound performed at 11 weeks gestation, the nuchal skin thickness is measured at 5 mm. Which of the following is not part of the differential?

(a) Normal variation

(b) Noonan’s syndrome

(c) Zellwegger syndrome

(d) Klippel-Feil syndrome

(e) Fragile X syndrome

Answer 18

(e) Fragile X syndrome

The nuchal skin thickness should measure up to 3 mm at 9-13 weeks, up to 5 mm at 14-19 weeks and up to 6mm at 19-24 weeks. Although rare (<1%) normal variation is observed. Other causes of nuchal skin thickening include Turners and Downs syndromes.

Question 19

55 A 30 week pregnant 23 year old lady with a history of previous Caesarian section is found to have extension of her placenta through the uterine scar. She undergoes an MRI study which shows extension of the placenta in to the bladder wall. What is the diagnosis?

(a) Placenta accreta

(b) Choriocarcinoma

(c) Placenta percreta

(d) Endometriosis

(e) Placenta increta

Answer 19

(c) Placenta percreta

In a normal pregnancy, the placenta is adherent to the endometrial lining. Penetration beyond this is abnormal and is categorisep according to depth of invasion. In placenta accreta there is superficial invasion of the myometrium by the placental villi, whereas deep invasion of the myometrium is termed placenta increta. Extension of the placental tissue to the peritoneum, often in to the adjacent organs, is termed placenta percreta. The incidence of abnormal placental implantation ranges from 1 in 533 to 1 in 2,500, with both foetal and maternal mortality associated, due to haemorrhagic complications.

Question 20

68 A 30 year old woman who is 10 weeks pregnant presents with bleeding and lower abdominal pain. US shows an endometrial thickness of 8 mm but gross distortion of its normal midline position by heterogeneous material, with no definite sac identified. What is the likely diagnosis?

(a) Complete miscarriage

(b) Incomplete miscarriage

(c) Delayed miscarriage

(d) Intrauterine haematoma

(e) Ectopic pregnancy

Answer 20

(b) Incomplete miscarriage

This condition can be asymptomatic and the typical findings on US are those of an expanded endometrial cavity packed with blood and the products of conception.

Question 21

28. You are asked to perform an antenatal ultrasound examination and note that the placenta has an unusual morphology. You see an additional lobule, which is separate from the main bulk of the placenta. What is this variant of placental morphology known as?

A. Circumvallate placenta.

B. Bilobed placenta.

C. Placenta membranacea.

D. Succenturiate placenta.

E. Placenta accreta.

Answer 21

28. D. Succenturiate placenta.

This is an additional lobule separate from the main bulk of the placenta. The signifi cance of this variant is the rupture of vessels connecting the two components or retention of the accessory lobe with resultant post-partum haemorrhage.

Circumvallate placenta has a chorionic plate smaller than the basal plate, with associated rolled placental edges. There is known to be an increased risk of placental abruption and haemorrhage with this type of placenta.

A bilobed placenta is a placenta with two evenly sized lobes connected by a thin bridge of placental tissue. This has no known increased risk of morbidity.

Placenta membranacea is a thin membranous structure circumferentially occupying the entire periphery of the chorion. There is an increased risk of placenta praevia, as a portion of the placenta completely covers the internal os.

Placenta acreta is not a variant of placental morphology. It occurs when there is superfi cial invasion of the chorionic villi of the placenta into the basalis layer of the uterine wall. Deeper invasion of the myometrium is termed ‘placenta increta’. Even deeper invasion involving the serosa or adjacent pelvic organs is termed ‘placenta percreta’. The risk of this is catastrophic intrapartum haemorrhage at the time of placental delivery.

Question 22

44. You are asked to assess a 24-year-old woman with TVUS. The patient presents with lower abdominal cramps and is approximately 5 weeks post last menstrual period (LMP). Her pulse and blood pressure are normal. B-HCG levels suggest that the patient is pregnant. On TVUS, no adnexal mass or free fluid is seen. Which of the following findings would you expect to see in the uterus to confirm that the patient does not have an ectopic pregnancy?

A. Pseudogestational sac.

B. Normal endometrium.

C. Trilaminar endometrium.

D. Double decidual sac sign.

E. Thin-walled decidual cyst.

Answer 22

44. D. Double decidual sac sign.

All the other answers are findings in the uterus that may be associated with ectopic pregnancy. In normal pregnancies, TVUS can demonstrate an intradecidual sign approximately 4.5 weeks after the last menstrual period. The intradecidual sign is a small collection of fluid that is eccentrically located within the endometrium and is surrounded by a hyperechoic ring. At approximately 5 weeks, the double decidual sac sign can be visualized. This consists of two concentric hyperechoic rings that surround an anechoic gestational sac in a normal intrauterine pregnancy. The secondary yolk sac may be identified at TVUS at approximately 5.5 weeks. Embryonic cardiac activity should also be visualized at TVUS at approximately 5–6 weeks, when the gestational sac measures at least 18 mm or when the embryonic pole measures at least 5 mm. A pseudogestational sac is a thick decidual reaction surrounding intrauterine fluid and is seen in approximately 10% of ectopic pregnancies. A trilaminar endometrium is formed during the late proliferative phase of the menstrual cycle. When an abnormal pregnancy is suspected on the basis of laboratory results, the absence of a true gestational sac in the presence of a trilaminar endometrium is highly suggestive of ectopic pregnancy. Thin-walled decidual cysts are seen at the junction of endometrium and myometrium, and may be seen in both normal and abnormal pregnancies. The thin wall differentiates it from a true gestational sac.

Question 23

11. A 24 year old woman attends A&E with lower abdominal pain and vaginal bleeding. A pregnancy test is positive. She is haemodynamically stable and an ultrasound is requested to confirm the presumed diagnosis of an ectopic pregnancy. Which of the following is the most common location for an ectopic pregnancy?

a. Cervix

b. Ovary

c. Abdominal cavity

d. Ampullary portion of the fallopian tube

e. Interstitial portion of the fallopian tube

Answer 23

11. d. Ampullary portion of the fallopian tube

The most common site of implantation is the fallopian tube, which accounts for over 90% of ectopic pregnancies. Ovarian and abdominal sites account for only approximately 3% and 1%, respectively. Within the fallopian tube the most common site is the ampulla (73%) followed by the fimbrial and interstitial regions

Question 24

12. A 26 year old pregnant woman attends for an obstetric ultrasound at 37 weeks. She is shown to have polyhydramnios. Which of the following would be a possible cause?

a. Cystic adenoid malformation

b. Ventricular septal defect

c. Infantile polycystic kidney disease

d. Posterior urethral valves

e. Intrauterine growth retardation

Answer 24

12. a. Cystic adenoid malformation

The remainder of the conditions listed above will cause oligohydramnios. Polyhydramnios is defined as amniotic fluid volume >1500–2000 cm3 at term. Most cases are due to maternal factors, with diabetes causing the majority of these. Oligohydramnios is defined as an amniotic fluid volume of <500 cm3 at term; the most common causes include demise of the fetus, drugs and renal anomalies.

Question 25

22. A 29 year old woman with a history of three previous failed pregnancies attends the ultrasound department for a scan. She has had a positive pregnancy test. Which of the following is not necessarily indicative of a failed pregnancy?

a. A crown rump length of 11 mm with no heartbeat detectable on TA scan

b. A crown rump length of 5 mm with no heartbeat detectable on TV scan

c. A gestation sac, mean sac diameter >20 mm with no visible yolk sac

d. A gestation sac, mean sac diameter >25 mm with no visible embryo

e. A flat M mode scan

Answer 25

22. b. A crown rump length of 5 mm with no heartbeat detectable on TV scan

In order to assess the presence or absence of a heartbeat accurately on TV scanning, the crown rump length needs to be >6 mm. On TA scanning the crown rump length needs to be >10 mm in order to accurately assess the absence of a heartbeat. The other options all represent signs of fetal demise. Usually two qualified ultrasound practitioners are required to assess a fetus if there is concern regarding embryonic demise.

Question 26

34. An 18 year old woman who is 32 weeks pregnant is referred for an obstetric ultrasound for ongoing abdominal pain. She is shown to have a small placenta relative to gestational age. Which one of the following would be a possible cause?

a. Molar pregnancy

b. Maternal diabetes

c. Umbilical vein obstruction

d. Pre-eclampsia

e. Maternal anaemia

Answer 26

34. d. Pre-eclampsia

Pre-eclampsia, IUGR, chromosomal abnormality and intrauterine infection can all cause a decrease in placental size. Enlargement of the placenta is defined as a measurement of >5 cm when obtained at right angles to the long axis of the placenta. The causes of placentomegaly include maternal diabetes, chronic intrauterine infection (e.g. syphilis), maternal anaemia, thalassaemia and twin–twin transfusion syndrome. Fetal chromosomal abnormalities may cause either a large or small placenta.

Question 27

35. A 27 year old woman who is 32 weeks pregnant is admitted with acute abdominal pain. The surgical team have requested an abdominal MRI to further investigate her pain before considering laparotomy. You are asked to protocol the request card. Which one of the following statements is correct?

a. The mother should be asked to lie prone for the scan

b. MRI should be avoided in the third trimester of pregnancy

c. Gadolinium diethylenetriaminepentaacetic acid (DTPA) chelate does not cross the placenta

d. Gadolinium-based contrast material crosses the placental membrane and circulates through the amniotic fluid

e. MRI would be the first imaging modality of choice

Answer 27

35. d. Gadolinium-based contrast material crosses the placental membrane and circulates through the amniotic fluid

The use of MRI in the evaluation of abdominal pain in pregnant patients is increasing. The primary imaging modality of choice, however, remains ultrasound, and MRI is usually reserved for situations where the ultrasound findings are equivocal. The use of gadolinium is not usually necessary in the investigation of abdominal pain in the acute setting and there is little evidence as to its effect on the fetus

Question 28

24 A 26-year-old patient with a positive B-HCG undergoes pelvic ultrasound examination. Which finding on ultrasound is most likely to indicate a nonviable pregnancy?

a The intradecidual sign

b Non-visualisation of cardiac activity when crown-rump length (CRL) is 7mm

C Visualisation of the yolk sac when the gestational sac is 8 mm

d Gestational sac present at 32 days

e Asymmetry of the echogenic ring surrounding the gestational sac at five weeks

Answer 28

24 Answer B: Non-visualisation of cardiac activity when crown-rump length (CRL) is 7 mm

At 6.5 weeks the CRL is approximately 5 mm and cardiac movement can be identified. The intradecidual sign is seen in intrauterine pregnancy. The gestational sac can be seen at the fundus from five weeks and is surrounded by an echogenic ring which can be asymmetric. The yolk sac is seen at approximately five to se en weeks when the gestational sac is 6-9 mm.

Question 29

33 A 22-year-old female patient presented with acute pelvic pain. She had a positive B-HCG result and the gynaecologist on call has asked you to look for an ectopic pregnancy. What ultrasound appearance would reassure you there is an intrauterine pregnancy?

a Pseudogestational sac

b Echogenic ring-like mass outside the uterus

c Decidual cysts

d `Ring of fire’ on colour Doppler imaging

e Double decidual sac sign

Answer 29

3 Answer E: Double decidual sac sign

The double decidual sac sign is seen at approximately five weeks of pregnancy and represents the inner rim of chorionic villi surrounded by a thin rim of fluid in the endometrial cavity which is surrounded by the echogenic decidua vera. The double decidua sign is highly reliable for intrauterine gestational sac. Note: intrauterine pregnancy does not exclude heterotopic (ectopic + coexistent intrauterine pregnancy) which occur in 1:6800-30000 pregnancies.

Question 30

38 A 42-year-old female patient who is 14 weeks’ pregnant has an episode of vaginal bleeding and is referred to hospital. The admitting obstetric doctor finds an enlarged uterus on examination and a raised B-HCG on blood tests. Ultrasound examination demonstrates a large echogenic mass with several small fluid-filled spaces within it within the uterus. What is the most likely diagnosis?

a Incomplete miscarriage

b Gestational trophoblastic disease

C Uterine carcinoma d Placental abruption

e Ectopic pregnancy

Answer 30

38 Answer B: Gestational trophoblastic disease

Gestational trophoblastic disease is a group of disorders that arise from aberrant fertilisation. The spectrum includes benign hydatidiform mole, invasive mole and choriocarcinoma. Maternal age >35 and <20 years, previous molar gestation and previous spontaneous abortion are risk factors.

Question 31

30 A 29-year-old female three days post partum is unwell with pelvic pain and fever. On clinical examination she has a palpable rope-like abdominal mass. What is the most likely diagnosis?

a Right ovarian thrombosis

b Left ovarian thrombosis

c Bilateral ovarian vein thrombosis

d Ruptured uterus

e Tubo-ovarian abscess

Answer 31

30 Answer A: Right ovarian thrombosis

This is the typical clinical scenario for ovarian vein thrombosis, which is an important differential to consider as it has a mortality of 5%. Eighty per cent occur in right ovarian vein, 14% bilateral and only 6% in left ovarian vein. On CT a tubular structure is seen of low density in the location of the vein.

Question 32

31 A 25-year-old has an ultrasound at 39 weeks gestation of a singleton pregnancy. The amniotic fluid volume is less than 500 mL. What is the most likely underlying cause for this?

a Severe growth restriction

b Maternal diabetes mellitus

c Trans-oesophageal fistula (TOF)

d Duodenal atresia

e Cystic adenomatoid lung

Answer 32

31 Answer A: Severe growth restriction

Oligohydramnios is when there is less than 500 mL of amniotic fluid at term. It is associated with a 20 times increase in foetal abnormalities and occurs with renal anomalies, intrauterine growth restriction (IUGR) and most commonly with premature rupture of the membranes. The other options are associated with polyhydramnios (amniotic fluid volume >1500-2000mL at term).

Question 33

32 A 39-year-old female patient is pregnant with her fourth baby. She undergoes routine obstetric ultrasound examination which demonstrates a thickened placenta with a thickness of 6 cm. What is the most likely diagnosis?

a Maternal diabetes mellitus

b IUGR

c Increasing maternal age

d Multiparity

e Maternal hypertension

Answer 33

32 Answer A: Maternal diabetes mellitus

Both maternal and foetal disease can cause enlargement of the placenta. Increasing maternal age and multiparity are risk factors for placenta praevia.

Question 34

33 A 24-year-old patient had an IUCD fitted two days ago by her general practitioner. She returned to the GP as she could not find the threads and was referred for an ultrasound. Both transabdominal and transvaginal ultrasound examination show an empty uterine cavity with no coil seen within it. There is a small amount of pelvic free fluid and possibly an echogenic linear structure, which may represent the coil outside the uterus in the right adnexa. What is the next most appropriate investigation?

a CT

b MRI

c Repeat ultrasound examination in one week

d Hysterosalpingogram

e Abdominal radiograph

Answer 34

33 Answer E: Abdominal radiograph

An abdominal radiograph is indicated if the coil is not definitely identified by ultrasound before referral to gynaecology

Question 35

34 A 17-year-old female patient with irregular periods and occasional pelvic discomfort undergoes transabdominal pelvic ultrasound examination. This shows a right ovarian volume of 17 mL and left ovarian volume of 15 mL. Both ovaries have several small cysts seen within them measuring approximately 5 mm in a peripheral location. What is the most likely diagnosis?

a Normal findings in this age group

b Patient currently on the oral contraceptive pill

c Polycystic ovary syndrome (PCOS)

d Ovarian hyperstimulation syndrome (OHSS)

e Endometriosis

Answer 35

34 Answer C: Polycystic ovary syndrome (PCOS)

PCOS occurs in 2.5 % and is associated with elevated LH levels with an increased LH/FSH ratio. The findings on ultrasound of slightly enlarged ovaries (>15 mL) occurs in 70%. The small cysts represent an excessive number of developing follicles and are small in size in comparison to OHSS where the cysts can be >10 cm and the ovaries themselves >5 cm.

Question 36

@# 21 A 31 year old is pregnant with her first child. At 16 weeks’ gestation the corrected alphafetoprotein level is noted to be raised. What is a possible cause for this?

a Wrong dates - a normal pregnancy that is less advanced that originally dated

b Greater than average birth weight

C Ectopic pregnancy

d Trisomy 21

e Neural tube defect

Answer 36

21 Answer E: Neural tube defect

An elevated alpha-fetoprotein level is associated with foetal anomalies in 61 %, of which 51 % are neural tube defects. Other causes include a normal pregnancy that is more advanced, twin pregnancy, missed abortion, renal anomalies and anterior abdominal wall defects.

Question 37

26 A 38-year-old female in her third trimester has an episode of painless vaginal bleeding. She is referred to the obstetric team and ultrasound examination is performed. This demonstrates the placenta is completely covering the internal os. What is the most likely diagnosis?

a Low-lying placenta

b Partial placenta praevia

C Placenta accreta

d Central placenta praevia

e Placenta increta

Answer 37

26 Answer D: Central placenta praevia

Central placenta praevia totally covers the internal os. Placenta accreta, increta and percreta are increasing degrees of the placenta growing into the myometrium with contact with the myometrium, myometrial invasion and penetration to the serosa respectively

Question 38

28 A pregnant patient with a family history of Beckwith-Wiedemann syndrome has an obstetric ultrasound examination which demonstrates that the foetus is growing along the 99.6th percentile and that there is polyhydramnios. What other condition is associated with the most likely diagnosis?

a Wilms’ tumour

b Neuroblastoma

C Neurofibromatosis

d Von Hippel-Lindau

e Down’s syndrome

Answer 38

28 Answer A: Wilms’ tumour

Beckwith-Wiedemann syndrome (omphalocoele, macroglossia, gigantism) is associated with increased risk of benign and malignant tumours of multiple organs: Wilms’ tumour >adrenocortical neoplasm >hepatoblastoma.

Question 39

33. A 36-year-old woman was diagnosed with complicated pregnancy on transvaginal ultrasound scan. What is the following is unlikely to be a possible diagnosis?

(a) Deflated yolk sac

(b) Hypoechoic area behind the choriodecidua

(c) Septated fluid behind the fetal neck

(d) A very large gestational sac relative to the embryo

(e) Herniated midgut into umbilical cord at 9 weeks

Answer 39

33. (e) Herniated midgut into umbilical cord at 9 weeks

All other fndings on US point to complicated pregnancy. Physiological herniation of bowel is seen from 8–11 w

Question 40

14. Regarding ultrasonography in the first trimester of pregnancy, which of the following are correct? (T/F)

(a) Gestational sac volume is the most accurate estimate of gestational age in the first 8 weeks of pregnancy.

(b) The diameter of the yolk sac should not be more than 5mm.

(c) The yolk sac is normally identified before the foetal pole.

(d) A normal intrauterine gestational sac and foetal pole exclude an ectopic pregnancy.

(e) Cardiac pulsation becomes visible at the beginning of the eighth postmenstrual week.

Answer 40

Answers:

(a) Not correct

(b) Correct

(c) Correct

(d) Not correct

(e) Not correct

Explanation:

Once the fetus can be identified (5-6wks) then crown to rump length (CRL) is the most accurate measurement. The biparietal diameter becomes the most accurate towards end of the first trimester. Cardiac pulsation is visualized as soon as a fetal pole is visualized i.e. at 6 weeks postmenstrual week on TAS. A coexistent intrauterine and ectopic pregnancy (heterotopic pregnancy) is extremely rare (1 in 30000 pregnancy).

Question 41

15. Which of the following statements are correct? (T/F)

(a) An empty gestational sac with a mean sac diameter of 10mm and an elevated â human chorionic gonadotrophin (HCG) is consistent with a blighted ovum.

(b) Beta-HCG levels double every week in the first 8 weeks of pregnancy.

(c) An absent intrauterine pregnancy on ultrasonography and â-HCG levels between 1000 and 2000 IU is highly suspicious of an ectopic pregnancy.

(d) Vaginal bleeding is not usually associated with an ectopic pregnancy.

(e) The risk of a second ectopic pregnancy is 10%.

Answer 41

Answers:

(a) Correct

(b) Not correct

(c) Correct

(d) Not correct

(e) Not correct

Explanation:

Beta-HCG levels double every 2-3 days in the first 8 weeks of pregnancy. Vaginal bleeding is seen in 75%-85% cases of ectopic pregnancies. The risk of second ectopic pregnancy is 25%.

Question 42

16. An axial ultrasonographic section through the foetal head measurement of the biparietal diameter (BPD) should include which of the following? (T/F)

(a) The third ventricle.

(b) The thalami.

(c) The cavum septum pellucidum.

(d) A continuous echogenic midline.

(e) The cerebellum.

Answer 42

Answers:

(a) Correct

(b) Correct

(c) Correct

(d) Not correct

(e) Not correct

Explanation:

BPD is used for estimating the gestational age after 12 weeks. Its accuracy declines after 28 weeks after which it is combined with second measurement like femur length.

Question 43

21. Regarding foetal anomalies, which of the following are correct? (T/F)

(a) The nuchal-fold thickness is most prominent between 11 and 13 weeks.

(b) Endocardial cushion defects are strongly associated with Down’s syndrome.

(c) The triple screen for Down’s syndrome refers to the combination of maternal alpha-fetoprotein, oestriol and HCG levels.

(d) Short femur and humerus lengths are indicators of Down’s syndrome.

(e) Separation of the big toe from the remaining toes is a strong sign of Down’s syndrome.

Answer 43

Answers:

(a) Correct

(b) Correct

(c) Correct

(d) Correct

(e) Not correct

Explanation:

Other associations with Down’s syndrome are membranous ventricular septal defects, ostium primum atrial septal defects, cleft mitral valve, patent ductus arteriosus, 11 pairs of ribs and hypersegmented manubrium (90%). Separation of the big toe from remaining toes (sandal sign) is a weak sign of Down’s synd.

Question 44

22. The following are correct regarding transabdominal ultrasound in early pregnancy: (T/F)

(a) Yolk sac is only visible from 7 weeks onwards.

(b) Gestational sac should be visible at 4 weeks.

(c) The earliest ultrasound sign of pregnancy is fundal endometrial thickening.

(d) Cardiac movement should be identifiable in the foetus at 6.5 weeks.

(e) Biparietal diameter can be used to predict gestational age from 7 weeks

Answer 44

Answers:

(a) Not correct

(b) Not correct

(c) Correct

(d) Correct

(e) Not correct

Explanation:

Yolk sac is visible from 6 weeks onwards and gestational sac from 5 weeks onwards. Biparietal diameter is used to predict gestational age from 12 to 28 weeks.

Question 45

29. Which of the following are correct regarding gestational trophoblastic disease: (T/F)

(a) Young maternal age is a risk factor.

(b) It is associated with theca-lutein cysts.

(c) A predominantly echo-poor mass is seen on ultrasound.

(d) Invasive mole develops in approximately half of cases.

(e) Raised human chorionic gonadotrophin is seen in upto 80% of cases.

Answer 45

Answers:

(a) Not correct

(b) Correct

(c) Not correct

(d) Not correct

(e) Not correct

Explanation:

Gestational trophoblastic disease is associated with increased maternal age, presents as an echogenic mass with invasive mole developing in 12%-15% of cases. Raised human chorionic gonadotrophin is seen in 100% cases.

Question 46

47. The following transvaginal ultrasound findings are compatible with pregnancy failure: (T/F)

(a) Double decidual reaction.

(b) A 2mm embryo lacking a cardiac heartbeat.

(c) A gestational sac of 20mm containing no yolk sac.

(d) Grossly distorted sac shape.

(e) A gestational sac of 25mm containing no embryo

Answer 46

Answers:

(a) Not correct

(b) Not correct

(c) Correct

(d) Correct

(e) Correct

Explanation:

Double decidual reaction consists of two concentric rings surrounding the intra-endometrial fluid and is a sign of normal pregnancy. Cardiac activity begins by 5 weeks of gestation hence heartbeat is seen in 5 mm or bigger embryo on transvaginal scan. Thus in embryos smaller than 5 mm repeat ultrasound is suggested.