Role Of Usg In Obstetrics

ROLE OF USG IN OBSTETRICS

Q. 1

Transvaginal USG can detect fetal cardiac activity in:

 A

6 weeks

 B

7 weeks

 C

8 weeks

 D

10 weeks

Q. 1

Transvaginal USG can detect fetal cardiac activity in:

 A

6 weeks

 B

7 weeks

 C

8 weeks

 D

10 weeks

Ans. A

Explanation:

Ans. is a i.e. 6 weeks 

Embryonic investigations suggest that cardiac contractions begin in fetus at 36 days gestational age.° This is evident on : Transvaginal USG

At 6 weeks of gestational age corresponding to 13 – 18mm of MSD Transabdominal USG           At 8 weeks of gestational age corresponding to 25 mm of MSD.

Note : MSD is mean Sac diameter

According to Williams Obs 23/e p 200   Using real time sunography with a vaginal transducer fetal cardiac activity ‘?0 hs seen as early as 5th menstrual week


Q. 2

Earliest detection of pregnancy by ultrasound is by:

 A

Gestation sac

 B

Fetal node

 C

FSH

 D

Fetal skeleton

Q. 2

Earliest detection of pregnancy by ultrasound is by:

 A

Gestation sac

 B

Fetal node

 C

FSH

 D

Fetal skeleton

Ans. A

Explanation:

Ans. is a i.e. Gestational sac

“The first definitive sonographic finding to suggest pregnancy is visualization of the gestational sac.” First sign of intrauterine pregnancy is presence of yolk sac within the gestational sac.°

Extra Edge

  • The position of a normal gestational sac is in the mid to upper uterus.
  • As the sac implants into the decidualized endometrium it is adjacent to the linear central cavity echo complex without displacing this echogenic anatomic landmark. This is known as Intradecidual Sign.
  • As the sac enlarges it gradually impresses on and deforms the central cavity echo complex giving rise to the characteristic sonographic appearance of the double decidual sac sign°

This sign is most effective with transabdominal sonography, performed at 5 – 6 weeks gestational age because using this approach, sonographer can confirm the presence of an intrauterine pregnancy before a yolk sac is identified.



Q. 3

Study of fetal parts in first trimester with least radiation hazard :

 A

X-ray abdomen

 B

Pelvimetry

 C

CT scan

 D

Ultrasound

Q. 3

Study of fetal parts in first trimester with least radiation hazard :

 A

X-ray abdomen

 B

Pelvimetry

 C

CT scan

 D

Ultrasound

Ans. D

Explanation:

Ultrasound


Q. 4

USG can detect gestation sac earliest at:

 A

5-6 weeks of gestation

 B

7-8 weeks of gestation

 C

10 weeks of gestation

 D

12 weeks of gestation

Q. 4

USG can detect gestation sac earliest at:

 A

5-6 weeks of gestation

 B

7-8 weeks of gestation

 C

10 weeks of gestation

 D

12 weeks of gestation

Ans. A

Explanation:

A i.e. 5-6 weeks of gestation 


Q. 5

All are signs /features of ectopic pregnancy on USG except

 A

Pseudo sac

 B

Hyprechoic ring

 C

Adenexal mass

 D

Echogenic mass with multicystic spaces within endometrial cavity

Q. 5

All are signs /features of ectopic pregnancy on USG except

 A

Pseudo sac

 B

Hyprechoic ring

 C

Adenexal mass

 D

Echogenic mass with multicystic spaces within endometrial cavity

Ans. D

Explanation:

D i.e. Echogenic mass with multicystic spaces within endometrial cavity


Q. 6

Ectopic pregnacny, characteristic finding in USG is:

 A

Absence of gestational sac in uterus 

 B

Complex adenexal mass

 C

Resistance in coloured Doppler

 D

Free fluid in peritoneal cavity

Q. 6

Ectopic pregnacny, characteristic finding in USG is:

 A

Absence of gestational sac in uterus 

 B

Complex adenexal mass

 C

Resistance in coloured Doppler

 D

Free fluid in peritoneal cavity

Ans. A

Explanation:

A i.e. Absence of gestational sac in uterus

Best method of diagnosing unruptured ectopic pregnancy is combination of transvaginal sonography & quantitative B-HCG valuesQ.


Q. 7

Most accurate assessment of gestational age by USG is done by

 A

Femur length

 B

Gestational sac size

 C

Menstrual history

 D

Crown rump length

Q. 7

Most accurate assessment of gestational age by USG is done by

 A

Femur length

 B

Gestational sac size

 C

Menstrual history

 D

Crown rump length

Ans. D

Explanation:

D i.e. Crown rump length


Q. 8

Investigation of choice in diabetic mother with a doubtful abnormal fetus:                          

March 2004

 A

USG

 B

Glycosylated hemoglobin

 C

Amniocentesis

 D

Chorionic villous biopsy

Q. 8

Investigation of choice in diabetic mother with a doubtful abnormal fetus:                          

March 2004

 A

USG

 B

Glycosylated hemoglobin

 C

Amniocentesis

 D

Chorionic villous biopsy

Ans. A

Explanation:

Ans. A i.e. USG


Q. 9

Accurate diagnosis of anencephaly on ultrasound can be done at:      

September 2005

 A

5 weeks of gestation

 B

8 weeks of gestation

 C

10 weeks of gestation

 D

14 weeks of gestation

Q. 9

Accurate diagnosis of anencephaly on ultrasound can be done at:      

September 2005

 A

5 weeks of gestation

 B

8 weeks of gestation

 C

10 weeks of gestation

 D

14 weeks of gestation

Ans. C

Explanation:

Ans. C: 10 weeks of gestation

In the first half of the pregnancy, the diagnosis is made by the elevated alfa-fetoprotein in amniotic fluid and confirmed by sonography.

The findings at 13 weeks are:

  1. Absence of cranial vault
  2. Angiomatous brain tissue

In the later half of the pregnancy the diagnosis is difficult specially when associated with hydramnios.


Q. 10

Ultrasound is done in 1st trimester for all except:

March 2009

 A

Multiple pregnancy

 B

Fetal anomalies

 C

To estimate gestational age

 D

To know the position of the placenta

Q. 10

Ultrasound is done in 1st trimester for all except:

March 2009

 A

Multiple pregnancy

 B

Fetal anomalies

 C

To estimate gestational age

 D

To know the position of the placenta

Ans. D

Explanation:

Ans. D: To know the position of the placenta

Benefits of first trimester USG:

  • Viability of the fetus
  • Pregnancy dating
  • Multiple pregnancy detection
  • Detection of ectopic pregnancy
  • Detection of H.Mole
  • Detection of fetal anomalies

Placental localization can be done with USG in second half of pregnancy.


Q. 11

Congenital anomalies that can be identified by USG are all except:     

September 2009

 A

Hydrops fetalis

 B

Esophageal atresia

 C

Anencephaly

 D

Cystic hygroma

Q. 11

Congenital anomalies that can be identified by USG are all except:     

September 2009

 A

Hydrops fetalis

 B

Esophageal atresia

 C

Anencephaly

 D

Cystic hygroma

Ans. D

Explanation:

Ans. D: Cystic Hygroma

Common anomalies that can be seen in USG are:

  • Cranial anomalies-anencephaly, hydrocephalus.choroid plaexus cysts
  • Spinal anomalies-Spina bifida occulta and Spina bifida aperta
  • Fetal heart
  • Fetal abdomen and abdominal wall-Esophageal atresia, omphalocoele, gastroschisis
  • Hydrops f etalis

Q. 12

Earliest fetal anomaly that can be diagnosed with USG:        

September 2009

 A

Duodenal atresia

 B

Fetal hydrops

 C

Down’s syndrome

 D

Anencephaly

Q. 12

Earliest fetal anomaly that can be diagnosed with USG:        

September 2009

 A

Duodenal atresia

 B

Fetal hydrops

 C

Down’s syndrome

 D

Anencephaly

Ans. D

Explanation:

Ans. D: Anencephaly

Many structural abnormalities in the fetus can be reliably diagnosed by an ultrasound scan, and these can usually be made before 20 weeks.

Common examples include hydrocephalus, anencephaly, myelomeningocoele, achondroplasia and other dwarfism, spina bifida, exomphalos, Gastroschisis, duodenal atresia and fetal hydrops.

First trimester ultrasonic ‘soft’ markers for chromosomal abnormalities such as the absence of fetal nasal bone, an increased fetal nuchal translucency (the area at the back of the neck) are now in common use to enable detection of Down syndrome fetuses.

Ultrasound can also assist in other diagnostic procedures in prenatal diagnosis such as amniocentesis, chorionic villus sampling, cordocentesis (percutaneous umbilical blood sampling) and in fetal therapy.


Q. 13

Best time for diagnosing fetal abnormalities by USG:

September 2009

 A

6-12 weeks of pregnancy

 B

13-19 weeks of pregnancy

 C

20-26 weeks of pregnancy

 D

27-32 weeks of pregnancy

Q. 13

Best time for diagnosing fetal abnormalities by USG:

September 2009

 A

6-12 weeks of pregnancy

 B

13-19 weeks of pregnancy

 C

20-26 weeks of pregnancy

 D

27-32 weeks of pregnancy

Ans. B

Explanation:

Ans. B: 13-19 weeks of pregnancy


Q. 14

Embryonic structure, identified earliest on USG, for confirmation of pregnancy is:

March 2011, March 2013

 A

Fetal pole

 B

Fetal Heart activity

 C

Gestation sac

 D

Fetal skeleton

Q. 14

Embryonic structure, identified earliest on USG, for confirmation of pregnancy is:

March 2011, March 2013

 A

Fetal pole

 B

Fetal Heart activity

 C

Gestation sac

 D

Fetal skeleton

Ans. C

Explanation:

Ans. C: Gestation sac

Gestation sac and embryonic yolk sac is identified at menstrual age of 5 weeks Fetal pole and cardiac activity is identified on USG at menstrual age of 6 weeks Lower limb buds, upper limb buds and spine at 7, 8 and 9 weeks respectively Remember:

  • Total duration of pregnancy: 280 days
  • Earliest detection of pregnancy by USG: Gestational sac
  • Pregnancy is confirmed by:

–        Fetal heart rate

–        Fetal sac on USG

–       Fetal movements

  • Transvaginal sonography detects gestational sac: at 14 days after ovulation

Q. 15

Best time to do USG in pregnancy, if it is to be done once in entire pregnancy, would be:         

March 2011

 A

6-8 weeks

 B

10-12 weeks

 C

18-22 weeks

 D

34-36 weeks

Q. 15

Best time to do USG in pregnancy, if it is to be done once in entire pregnancy, would be:         

March 2011

 A

6-8 weeks

 B

10-12 weeks

 C

18-22 weeks

 D

34-36 weeks

Ans. C

Explanation:

Ans. C: 18-22 weeks

Routine USG at 18-22 weeks gestation has the following effects 1) reduces the incidence of post-term pregnancy (39%) and rates of induction of labour for post-term pregnancy, 2) increases early detection of multiple pregnancy (92%), 3) increases early detection of major fetal anomalies when termination is possible, 4) no significant differences in the clinical outcomes such as perinatal mortality and 5) reduces neonatal admission to special care baby unit (14%)


Q. 16

Best parameter by USG to assess fetal maturity:

 A

Crown rump length at 16 weeks

 B

Head circumference at 36 weeks

 C

Biparietel diameter at 12 weeks

 D

Femur length at 12 weeks

Q. 16

Best parameter by USG to assess fetal maturity:

 A

Crown rump length at 16 weeks

 B

Head circumference at 36 weeks

 C

Biparietel diameter at 12 weeks

 D

Femur length at 12 weeks

Ans. C

Explanation:

Ans. Biparietel diameter at 12 weeks


Q. 17

The condition shown in the image below can be diagnosed by USG as early at which week of gestation? 

 A

5 weeks of gestation.

 B

8 weeks of gestation.

 C

10 weeks of gestation.

 D

14 weeks of gestation.

Q. 17

The condition shown in the image below can be diagnosed by USG as early at which week of gestation? 

 A

5 weeks of gestation.

 B

8 weeks of gestation.

 C

10 weeks of gestation.

 D

14 weeks of gestation.

Ans. C

Explanation:

Ans:C.)10 weeks of gestation.

The condition shown in the picture above represents anencephaly.

Anencephaly 

  • It is characterised by absence of the cranial vault and cerebral hemispheres.
  • It is the most common type of neural tube defect.
  • Occurs when the rostral (head) end of the neural tube fails to close, usually between the 23rd and 26th day following conception
  • Anencephaly may be sonographically detectable as early as 10 weeks.
  • Ultrasound has an accuracy of approximating 100% at 14 weeks
  • Features seen are:
    • no parenchymal tissue is seen above the orbits and calvarium is absent: parts of the occipital bone and mid brain may be present
    • less than expected value for crown rump length (CRL)
    • a “frog eye” or “mickey mouse” appearance may be seen when seen in the coronal plane due to absent cranial bone/brain and bulging orbits.
    • may show evidence of polyhydramnios: due to impaired swallowing



Q. 18

 Typical appearance of Uterus on USG Photograph is seen in 

 A

Menstruation

 B

Hydatiform mole 

 C

Twin pregnancy 

 D

Acute hydramnios

Q. 18

 Typical appearance of Uterus on USG Photograph is seen in 

 A

Menstruation

 B

Hydatiform mole 

 C

Twin pregnancy 

 D

Acute hydramnios

Ans. B

Explanation:

Hydatiform mole (Appearance shown: Snow storm appearance) 

Molar pregnancy is an abnormal form of pregnancy in which a non-viable fertilized egg implants in the uterus and will fail to come to term. A molar pregnancy is a gestational trophoblastic disease which grows into a mass in the uterus that has swollen chorionic villi. These villi grow in clusters that resemble grapes. A molar pregnancy can develop when a fertilized egg does not contain an original maternal nucleus. The products of conception may or may not contain fetal tissue. It is characterized by the presence of a hydatidiform mole (or hydatid molemola hydatidosa). Molar pregnancies are categorized as partial moles or complete moles, with the word mole being used to denote simply a clump of growing tissue, or a growth.


Q. 19

First trimester USG finding in Down syndrome‑

 A

Nuchal thickening

 B

Nuchal translucency

 C

Cardiac anomalies

 D

GI anomalies

Q. 19

First trimester USG finding in Down syndrome‑

 A

Nuchal thickening

 B

Nuchal translucency

 C

Cardiac anomalies

 D

GI anomalies

Ans. B

Explanation:

Ans. is ‘b’ i.e., Nuchal translucency



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