Chpt. 60 Fetal Thorax

Question 1

What is the single most important determinant for fetal viability?

Answer 1

Adequacy of pulmonary development

Question 2

What is the major reason why fetuses younger than 24 weeks of gestation are generally considered nonviable?

Answer 2

Pulmonary immaturity

Question 3

Breathing movements that occur before birth results in ?

Answer 3

The aspiration of fluid into the lungs

Question 4

Name the three routes that fluid in the lungs (at birth) are cleared by?

Answer 4

1) through the mouth and nose
2) into the pulmonary copillaries
3) into the lymphatic’s and pulmonary vessels

Question 5

The fetal thorax is examined in what planes?

Answer 5

transverse and coronal or parasagittal plane

Question 6

what is the normal shape of the thoracic cavity?

Answer 6

symmetrically bell shaped, with the ribs forming the lateral margins, the clavicles forming the upper margins, and the diaphragm forming the lower margin

Question 7

The lungs serve as lateral border for ? and lie superior to ?

Answer 7

heart and diaphragm

Question 8

How much fluid is in the lungs at birth?

Answer 8

They are half full

Question 9

describe the diaphragm sonographically

Answer 9

echogenic smooth hypoechoic muscular margin between the fetal liver or spleen and the lungs

Question 10

Which is normally slightly smaller? thorax or abdominal cavity

Answer 10

thorax

Question 11

where are the chest circumference measurements made from?

Answer 11

transverse plane at the level of the four chamber view of the heart

Question 12

A fetus with a significant narrow diameter of the chest may have?

Answer 12

asphyxiating thoracic dystrophy

Question 13

What syndrom is associated with asphyxiating thoracic dystrophy?

Answer 13

Thanatophoric dwarfism

Question 14

The central portion of the thorax is occupied by the _________.

Answer 14

mediastinum

Question 15

Majority of the heart is positioned in the ?

Answer 15

midline and left chest

Question 16

How should the apex of the heart be directed?

Answer 16

toward the left chest wall at an axis that is 45 degrees from midline

Question 17

The heart occupies _______ of the chest?

Answer 17

1/3

Question 18

What direction does the base of the heart lie to the diaphragm?

Answer 18

Horizontal

Question 19

why is the location of the heart important to document?

Answer 19

as detection of abnormal heart position may indicate the presence of a chest mass, pleural effusion, or cardiac malformation

Question 20

How do the fetal lungs appear sonographically?

Answer 20

homogenous with moderate echogenicity

Question 21

In early gestation, the lungs are similar to or slightly _____ echogenic than the liver?

Answer 21

less

Question 22

As gestation progresses, there is a trend toward increased pulmonary echogencicty relative to ?

Answer 22

liver

Question 23

When is fetal breathing movements considered absent?

Answer 23

if no such fetal activity is noted during a 20 minute observation period

Question 25

what is used to detect fetal breathing through the nostrils?

Answer 25

Color flow doppler

Question 26

when does fetal breathing become more prominent?

Answer 26

2nd and 3rd trimesters

Question 27

The mature fetus spends how much time breathing?

Answer 27

almost 1/3

Question 28

when are fetal breathing movements documented?

Answer 28

when seesaw movements of the fetal chest or abdomen are sustained for 20 seconds

Question 29

What should you evaluate when looking at a fetus for a lung mass?

Answer 29

1) postion of the heart 2) orientation of the cardiac axis 3) Measurement of the thoracic circumference

Question 30

What should you look for when the heart position and axis vary from the normal position?

Answer 30

any abnormality that may be the cause of such displacement

Question 31

What is fetal echo beneficial for excluding?

Answer 31

cardiac involvement, and evaluation of an intact diaphragm is necessary to exclude diaphragmatic hernia

Question 32

The lungs will not grow or develop properly when?

Answer 32

1) small uterine cavity resulting from severe oligohydraminos 2) chest cavity os abnormally small 3) When the balance between tracheal and airway pressure and fluid volume is inadequate 4) fetus is unable to practice breathing movement

Question 33

**_Pulmonary Hypoplasia_** is caused by?

Answer 33

a decrease in the number of lung cells, airways and alveoli, with a resulting decrease in organ size and weight

Question 34

Pulmonary hypoplaia results in?

Answer 34

small inadequate development of lungs

Question 35

pulmonary hypoplasia most commonly occurs from _________ \_\_\_\_\_\_\_\_\_ or is secondary to a small thoracic cabity as a result of a structural or ________ \_\_\_\_\_\_\_\_\_.

Answer 35

prolonged oligohydraminos; chromosomal abnormality

Question 36

Pulmonary hypoplasia may also occur in fetuses with?

Answer 36

severe intrauterine grown restriction and early rupture of the membranes

Question 37

Pulmonary hypoplasia may be caused by ?

Answer 37

masses within the thoracic cavity

Question 38

Name the masses withing the thoracic cavity? (5)

Answer 38

1) pleural effusion 2) diaphragmatic hernia 3) cystic adenomatoid malformatin of the lung 4) bronchopulmonary sequestation 5) other lg. cyst and tumors of the lungs and thorax, may lead to pulmonary hypoplasia

Question 39

what may manifest with pulmonary hypoplasia?

Answer 39

cardiac defect, skeletal dysplasias, central nervous system disorder, and chromosomal trisomies ( 13, 18 and 21)

Question 40

Sonographic finding of pulmonary hypoplasia

Answer 40

1) Thoracic measurements 2) various lung measurements 3) estimation fo lung volume 4) doppler studies of the pulmonary arteries 5) assessment of fetal breathing activity

Question 41

Accumulation of fluid within the pleural cavity that may appear as an isolated lesion or secondary to multiple fetal anomalies is called?

Answer 41

**_pleural effusion or hydrothorax_**

Question 42

what is the sonographic appearance of pleural effusion?

Answer 42

echo free peripheral masses on one or both sides of the fetal heart

Question 43

\_\_\_\_\_\_\_\_ are ehco free masses that replace normal lung parenchyma

Answer 43

Lung Cyst

Question 44

Lung cystic masses may cause notable shifts of the ?

Answer 44

intrathoracic structures

Question 45

what is the most common lung cyst detected prenatally?

Answer 45

**_Bronchogenic cyst_**

Question 46

where does bronchogenic cyst usually occur?

Answer 46

within the mediastinum or lung; infrequently they are inferior to the diaphragm

Question 47

Sonographically the bronchogenic cyst appear?

Answer 47

as small circumscribed masses without evidence of a mediastinal shift or heart failure amniotic fluid volume is within a norma range

Question 48

Pleural effusions conform to the _______ cavity and often compress ________ tissue.

Answer 48

thoracic, lung

Question 49

T/F; The lung appears to float in fluid

Answer 49

True

Question 50

Pleural fluid is rarely encountered before the _____ week of gestation, except in association with _______ or\_\_\_\_\_\_\_ syndrom

Answer 50

15th, down or turner's

Question 51

compression of lung parenchyma may cause?

Answer 51

pulmonary hypoplasia (repersent life threating consequence for neonate)

Question 52

The presence of a pleural effusion may cause a shift of ?

Answer 52

mediatinal structures, compression fo the heart, and inversion fo the diaphragm

Question 53

In the presence of _____ the shpe of the lung appears normal

Answer 53

pleural effusion

Question 54

Once a pleural effusion has been discovered a careful search for ______ (3)should be attempted?

Answer 54

cardiac, lung, and diaphragmatic lesions

Question 55

when pleural effusion is large, lung develoopment is impaired, which may result in?

Answer 55

pulmonary hypoplasia

Question 56

with pleural effusion signs of ________ should be performed?

Answer 56

hydrops (ascites, scalp edema, and tissue edema)

Question 57

solid tumors of the fetal lungs appear as?

Answer 57

echo dense masses in the lung tissue

Question 58

Name two solid lung masses?

Answer 58

pulmonary sequestration and certain types of cystic ademomatoid malformations

Question 59

\_\_\_\_\_\_\_\_\_\_ is a supernumerary lobe of the lung, separated from the normal tracheobronchial tree

Answer 59

pulmonary sequestration

Question 60

In pulmonary sequestration, extra pulmonary tissue is present within the ______ \_\_\_\_\_\_ ___ or is connected to the inferior border of the _______ within its own pleural sac.

Answer 60

pleural lung sac; lung

Question 61

In solid lung masses the lung tissue is nonfuntional and recieves its blood supply for what?

Answer 61

systemic circulation

Question 62

In solid lung masses the arterial supply is usually from?

Answer 62

thoracic aorta, with venous drainage into the vena cava

Question 63

Sonographically solid lung mass appear?

Answer 63

echo-dense solid mass resembling lung tissue is observed, usually in the lower lobe of the lung

Question 64

Majority of extralobar defects occur on the ?

Answer 64

left side, rarely below the diaphragm

Question 65

describe intralobar lesions?

Answer 65

spherical, and extralobar sequestration appears as a cone shaped or triangular mass

Question 66

\_\_\_\_\_\_ is one of the bronchopulmonary foregut malformations?

Answer 66

CCAM

Question 67

is a multicystic mass within the lung consisting of primitive lung tissue and abnormal bronchial and bronchiolar-like structures?

Answer 67

**_Congenital cystic adenomatioid malformation_**

Question 68

How may forms of cystic adenomatoid malformation are there?

Answer 68

3 1) CCAM type I 2) TypeII 3) type III

Question 70

one or more large systs replace normal lung tissue ) single or multiple cysts measuring more than 2 cm and up to 19 cm)

Answer 70

CCAM type I

Question 71

Type II of cystic adenomatoid malformation constist of ?

Answer 71

multiple small cysts (less than 1 cm)

Question 72

In cystic adenomatoid malformation type II lesions are assoicated with?

Answer 72

fetal and/or chromosomal abnormalities in 25% of cases

Question 73

In type II lesions of cystic adenomatoid malformation name the three chromosomal abnormalities?

Answer 73

1) renal agenesis 2) pulmonary anomalies 2) diaphragmatic hernia

Question 74

Type III malformation fo cystic adenomatoid are characterized as?

Answer 74

bulky, large, noncystic lesions appearing as echo-dense masses of the entire lung lobe