Biometry

Question 1

How do you measure BPD

Answer 1

outer to inner from left to right

Question 2

How do you measure head circumference (HC) ?

Answer 2

right to left

Question 3

What is doliocephaly?

Answer 3

When the AP diameter is longer than the transverse diameter and the CI is less than 70%

Question 4

wht plane do we use to measure the BPD and HC

Answer 4

transthalamic plane

Question 5

What anatomy should be seeen when measuring the BPD

Answer 5

3rd ventricle, thalami, and cavum septi pellucidi

Question 6

Where do you measure the head circumference?

Answer 6

through a plane that crosses the 3rd ventricle, thalami, and CSP.

Question 7

Where is Cavum septi pellucidi located?

Answer 7

in the anterior portion of the brain

Question 8

How should the calvaria (skull) appear sonographically?

Answer 8

smooth, symmetrical, and hyperechoic

Question 9

How does the cavum septi pellucidi (CSP) appear sonographically?

Answer 9

a box like structure in the anterior portion of the brain

Question 10

What are the hyperechoic structures in the CSP image?

Answer 10

the medial walls of the lateral ventricle

Question 11

What is the structure that is inferior to the CSP and shows up as three hyperechoic lines

Answer 11

columns of fornix which represents paired nerve columns

Question 12

What view is best for visualizing the columns of fornix?

Answer 12

transaxial plane

Question 13

Dolicocephaly is commonly seen with what conditions

Answer 13

oligohydraminos and multiple gestations

Question 14

What is oligohydraminos

Answer 14

low amounts of amniotic fluid (less than 5 cm)

Question 15

Brachycephaly is commonly seen with what conditions

Answer 15

trisomy 21, hydrocephalus, synostosis (premature fusion of bones)

Question 16

Where should the abdominal circumference measurement be taken?

Answer 16

in a transverse plane at the level of the portal and umbilical veins and stomach.

Question 17

Where should the calipers be placed when measuring the abdominal circumference

Answer 17

outside skin line

Question 18

What should the transducer be placed when measuring a fetal femur

Answer 18

perpendicular with the bone

Question 19

what should not be included in the femur measurement?

Answer 19

the epiphysis at the ends of the bone

Question 20

What is the normal value of a Nuchal Thickness? What is an increased thickness associated with?

Answer 20

The normal value is <6 mm between 15-21 weeks. If it exceeds this, it might indicate down syndrome

Question 21

What plane and where is Nuchal Thickness measured?

Answer 21

in an axial plane at the level of the cerebellum and cisterna magna

Question 22

Where are calipers placed when measuring nuchal thickness

Answer 22

outer edge of bone to outer edge of skin

Question 23

In what plane and where do you measure the lateral ventricle? Where do you put the calipers?

Answer 23

axial view, posterior to the glomus of the choroid plexus. The calipers are placed on the inner to inner walls of the ventricle

Question 24

What is the normal width of the lateral ventricle?

Answer 24

less than 10 mm

Question 25

In what plane and where do you measure the cisterna magna? Where do you put the calipers?

Answer 25

in an axial plane in the same view as the nuchal fold. It is measured anterior to posterior.

Question 26

Where do you put the calipers when measuring the cerebellum?

Answer 26

They are placed on the outer edge to outer edge of the cerebellar hemispheres and are measuring right to left.

Question 27

What is the difference in shape between the cisterna magna and cerebellum?

Answer 27

The cerebellum is shaped more like a peanut and the cisterna is more like an M

Question 28

What are the measurements required during a biometry protocol? How are they measured?

Answer 28

3 BPD measurements (outer to inner), 3 head circumferences, 3 abdomen circumferences (including stomach and umbilical vein), 3 femur and 3 humerus lengths.

Question 29

What are the head measurements required during a biometry protocol?

Answer 29

cerebellum, nuchal thickness, lateral ventricle, cisterna magna

Question 30

What are the heart images required during a biometry protocol?

Answer 30

M-mode fetal heart measurement, M-mode cine