General, Atelectasis & Congenital Flashcards
What are the anatomic divisions of the tracheobronchial tree?
R/L primary main bronchi –> lobar bronchi –> segmental bronchi –> terminal bronchioles –> respiratory bronchioles –> alveolar ducts –> alveolar sacs –> alveoli
True or false: the trachea cartilaginous rings are “O” shaped.
False. They are C/U shaped and are covered posteriorly by a flat band of muscle/connective tissue.
What is the difference between the right and left main stem bronchus?
Right – wider, shorter & more vertical
Left – narrower, longer & horizontal
What are the pores of Kohn?
Small communications between adjacent pulmonary alveoli.
What is an advantage and disadvantage of the pore of Kohn?
Advan: Collateral pathway for for gaseous transit when there’s proximal obstruction.
Disadvan: Pathway for dissemination of infection or malignancy.
What does the right B7 segment correspond to using the Boyden system?
Right medial segment of the lower lobe.
What does the left B4 segment correspond to using the Boyden system?
Left superior segment of the lingula “lobe”.
What does the right B4 segment correspond to using the Boyden system?
Right lateral segment of the middle lobe.
What are the canals of Lambert?
Direct communication between the alveoli and bronchioles.
Which hilar shadow is higher and why?
Left (90%) – because the pulmonary artery ascends over the left main and upper lobe bronchus
On a lateral chest view, which main stem bronchus is visualized more superiorly?
The right main stem bronchus.
What are the 4 components of the parietal pleura?
a) costal part
b) mediastinal part
c) diaphragmatic part
d) Cervical part
The apex of the lung is above which rib level?
1st
True or False: The major fissure starts at the T5 level?
True. It terminates at the anterior diaphragm.
True or False: Majority of people have complete normal fissures.
False. Majority have incomplete fissures.
At what level does the minor fissure run?
4th anterior rib
What % of the pop’n has an azygous lobe?
1%
What is the inferior accessory lobe/fissure?
Separates medial basal segment from rest of lower lobe.
What is the superior accessory fissure?
Separates superior segment of lower lobe from rest of basal segments.
On what side is the superior accessory fissure?
Both but R>L
What is the left minor fissure?
Separates lingula from rest of upper lobe.
Which accessory fissure is the M/C?
The inferior accessory fissure.
What are the 3 normal openings (for passage of vessels/organs) in the diaphragm called and at what levels do they occur?
a) Inferior vena cava hiatus (T8)
b) Esophageal hiatus (T10)
c) Aortic hiatus (T12)
What does the diaphragm attach to peripherally?
Ribs 6-12
What is the normal excursion of the diaphragms?
~3.5cm –> differences do not correlate with vital capacity
What % of diaphragm scalloping is normal? What side do they commonly occur?
5%; M/C on right
What is the ratio of air to soft tissue density in the lung?
11:1
What are 3 chest disease patterns that may present with air bronchograms?
a. Consolidation
b. Atelectasis
c. Interstitial thickening
What are the two major subtypes of atelectasis?
a. Obstructive Atelectasis – cause resorption atelectasis
- endobronchial lesions
- extrinsic bronchial compression
b. Non-obstructive Atelectasis
- relaxation
- adhesive
- cicatrization
What is the M/C form of atelectasis?
Resorption –> resorption of gas distally d/t a proximal obstruction
A resorptive collapse can be seen radiographically within what time frame?
1 hour
How long does it take all the air to disappear in atelectasis?
18-24hrs (other sources say 24-48hrs)
Lungs collapse quicker if the lungs are filled with MORE or LESS oxygen?
more –> faster absorption into alveolar capillaries
What are 2 types of relaxation atelectasis?
a. Passive
b. Compressive
What is passive atelectasis?
Retraction of lung tissue d/t a mass effect of air or fluid collection within the pleural space.
What are you likely to see in a collapsed lung in cases of passive atelectasis?
Air bronchograms (indicates collapse is not resorptive)
What is compressive atelectasis?
Intrapulmonary mass compresses adjacent lung parenchyma.
What is adhesive atelectasis?
Collapse in the presence of open airways (eg. inactivation of surfactant).
What is the function of surfactant?
Keeps surface tension low and thus prevents collapse of lung.
What is cicatrization atelectasis and what are the two subtypes?
Collapse d/t underlying, irreversible infectious or inflammatory process which causes fibrosis.
Local – eg. scarring in upper lobe from TB
Generalized – eg. diffuse interstitial fibrosis
What is platelike atelectasis?
Form of adhesive atelectasis.
Alveolar collapse from various causes: general anesthesia, surgery, trauma, phrenic nerve paralysis, mucus plugging, asthma.
What are the aka’s for platelike atelectasis (including the eponym)?
- Discoid
- Liner
- Subsegmental
- Fleischner Lines
What are the aka’s for round atelectasis?
- folded lung
- Blesovsky syndrome
- atelectatic pseudotumor
What is the cause of round atelectasis?
Form of passive atelectasis – infolding of a redundant pleura.
Local pleuritis caused by irritants such as asbestos or other pleural diseases/thickening.
What radiographic sign can be associated with round atelectasis?
Comet-tail sign
How does CT contrast help in differentiating between round atelectasis and a lung tumor?
It doesn’t. They both enhance.
What are the direct signs of atelectasis?
a. Displacement of interlobular fissures
b. Crowding of bronchovascular structures. (DI Chest)
What are the indirect signs of atelectasis?
a. Elevation of diaphragm
b. Mediastinal displacement
c. Compensatory overinflation
d. Hilar displacement
What are specific radiographic signs of a right upper lobe collapse?
a. juxtaphrenic peak
b. golden S sign
c. R hilum elevated
What are specific radiographic signs of a right middle lobe collapse?
a. silhouette sign of R cardiac border
b. inferior displacement of minor fissure & anterior displacement of major fissure
What are specific radiographic signs of a left upper lobe collapse?
a. Luftsichel sign
b. silhouette sign of left cardiac border and aortic knob
c. vertical major fissure
What is middle lobe syndrome in reference to atelectasis?
Chronic/recurrent non-obstructive middle lobe collapse d/t chronic inflammatory disease.
What is the flat waist sign?
Flatten of the aortic knob and main pulmonary artery d/t severe collapse of left lower lobe.
What is corona radiata in reference to lung nodules?
Linear spicules/strands radiating outwards from a pulmonary nodule. Usually specific for malignant lung cancer.
What is rigler’s notch in reference to lung nodules?
Indentation in a solid lung mass, representing a feeding vessel –> signifies bronchial carcinoma
(Although, can also be seen in granulomatous infections.)
What is the difference between a pulmonary air cavity and a pulmonary abscess (except for the contents)?
Cavity communicates with the bronchial tree, allowing for air to replace necrotic material.
What does the wall thickness of a pulmonary cavity signify?
The thicker the wall, the higher malignant risk.
1mm = 100% benign 5-15mm = 50% benign/malignant >15mm = 92% malignant
What is the definition of an intrathoracic lesion’s doubling time and what is its significance?
Time it takes for a nodule to double its volume. Volume doubling times faster than 1 month and less than 2 years suggest more malignant-type processes.
What is the M/C/C of Ca2+ pulmonary nodule?
Healed primary granuloma
Ca2+ of a pulmonary nodule, classically signifies what about the lesion?
Its benign (of course there are exceptions).
What are some signs of a Ca2+ non-malignant pulmonary lesion?
- Ca2+ is more peripheral
- Ca2+ is more diffuse & punctate
Loculated trapped fluid in the minor fissure that disappears quickly is called?
Vanishing tumor sign
What are the smallest size objects that can be identified by HRCT?
100-400um
What is the black bronchus sign?
The airways are more obvious (“blackness”) when surrounding parenchyma is ground-glass.
Bronchial walls should not be seen within how many cm of the costal pleura?
1cm
What is the signet ring sign as seen in the chest?
bronchial dilatation
Which side is pulmonary agenesis most common and which side has the worst prognosis?
What other conditions are associated with pulmonary agenesis?
Right = left;
Right worse prognosis
Associated with concomitant heart/skeleton/GI tract/GU malformations.
What is the difference between pulmonary aplasia and hypoplasia?
Aplasia = absence of lung tissue but rudimentary bronchus present
Hypoplasia = morphology normal; incomplete development; hemithorax smaller
What are the 3 subtypes of pulmonary hypoplasia and which one is M/C?
a. Primary unilateral pulmonary hypoplasia
b. Primary bilateral pulmonary hypoplasia
c. Secondary pulmonary hypoplasia – M/C
What is scimitar syndrome?
Hypoplastic lung & right pulmonary artery. Anomalous right pulmonary vein drains into the vena cava (or right atrium or portal vein).
What is the M/C/C of unilateral secondary hypoplasia?
Intrathoracic compression from a congenital diaphragmatic hernia.
What is bronchopulmonary sequestration?
Sequestered pulmonary tissue that does not communicate with central airway thru normal bronchial connection. It also receives its blood supply via the systemic circulation rather than pulmonary system.
What are the types of bronchopulmonary sequestration? Which one is more common?
Where is the M/C location?
Interlobar (75%) & Extralobar (15%)
M/C location = left lower lobe
What are the differences btwn intralobar and extralobar sequestration?
Intralobar = within normal lung tissue
= pulmonary venous drainage
= other congenital anomalies uncommon
= diagnosed before age 20
= M=F
Extralobar = separate w/ own pleural covering
= systemic venous drainage
= other congenital anomalies frequent
= diagnosed mostly within 1st year
= M:F = 4:1
What is the M/C foregut duplication cyst?
Congenital bronchial cyst
What is congenital bronchial cyst and where is the M/C location?
It is a closed budding of the tracheobronchial tree.
M/C location = mediastinum - hilar & carina (as opposed to parenchyma)
What is congenital bronchiectasis?
Dilation of proximal and medium-sized bronchi caused by destruction of muscular and elastic components of the bronchial wall.
What is Williams/Campbell syndrome?
Deficiency in amt of cartilage in subsegmental bronchi –> distal airway collapse and bronchiectasis
Abnormal lung tissue containing adenomatous tissue within a communicating cyst best describes which condition?
Congenital (cystic) adenomatoid malformation (CCAM)
Which type of CCAM is M/C and what are its features?
Type 1 (40%)
- one large cyst surrounded by smaller cysts
- best prognosis
- unilateral
a) Which type of CCAM presents with stillborn babies?
b) Which type of CCAM is associated with lethal cardiac or renal anomalies?
a) Type 3
b) Type 2
How does tracheomalacia present on inspiration/expiration films?
Inspiration = Dilation of trachea Expiration = Collapse of trachea
What is the name of a caudally tapered trachea?
Funnel/Carrot-shaped trachea
What is the triad of findings associated with congenital bronchial atresia?
1) Central mucocele
2) Hyperlucency
3) Hypoperfusion
What happens to the distal airways/airspaces in congenital bronchial atresia?
They develop normally and fill d/t collateral pathways.
Where is the M/C location for congenital bronchial atresia?
Upper lobes
What is Wilson-Mikity syndrome?
Found in pre-mature babies with low birth weight and are ventilated. Early development of cystic interstitial emphysema (PIE). (Emphysematous blebs & thickened alveolar walls.)
What is the cause for congenital lobar emphysema?
Unknown; but 3 theories exist:
1) Immaturity of bronchial cartilage –> bronchial collapse during expiration
2) Endobronchial obstruction – eg. mucosal folds/plugs
3) Bronchial compression from vascular structure
What are the clinical & radiographic features of congenital lobar emphysema?
- Males! (3:1)
- 90% before 6 months
- overinflation of a lobe
What is the VACTERL complex?
V = vertebral anomalies A = anal atresia C = cardio anomalies TE = tracheoesophageal fistuale R = renal anomalies L = limb anomalies (radial ray anomalies, syndactyly)
What is the M/C type of tracheoesophageal fistuale?
Type 3B (fistula between lower segment of trachea and esophagus - H shaped)
What is a type 1 tracheoesophageal fistula?
Complete absence of esophagus
What is the name of the condition where the right side has 2 lobes and the left side has 3?
Pulmonary Isomerism
Which pulmonary artery is more likely to be absent? Where does the pulmonary blood supply come from on that side instead?
Right
Blood supply comes from ascending aorta, aortic arch or right subclavian artery.
What is the pulmonary sling?
The LEFT pulmonary artery slings behind the trachea (between trachea and esophagus).
Which MSK condition is associated with pulmonary artery stenosis or coarctation?
Ehlers-Danlos syndrome
What is the M/C congenital venous anomaly?
A left superior vena cava
What is M/C form of an anomalous pulmonary venous drainage?
Supracardiac (50%) – drains into left SVC
What are other venous drainage options in left to right shunts?
- Right atrium
- Portal vein (infradiaphragmatic)
- Mixed
Which phakamatosis should you think of with arteriovenous fistulas?
Rendu-Osler-Weber (aka. Hereditary Hemorrhagic Telangiectasia)
What location is more common for AVMs in the lung?
Lower lobes
Which congenital pulmonary lymphangiectasis group is most common?
Group II – lymphatics fail to regress while lung parenchyma continues to grow
Fatal!
What is the name of the condition that results from failure of separation of the GI tract from the primitive neural crest?
Neurenteric cyst
Where do neurenteric cysts M/C occur and what are they associated with?
M/C occur in posterior mediastinum @ level of carina – have an intraspinal component.
There is a high association with vertebral anomalies (eg. butterfly, hemivertebra etc.).
Congenital lobar emphysema M/C affects which lobe?
Left upper lobe (less commonly R middle lobe)
What is the differential diagnosis for a pulmonary miliary pattern?
- TB
- Histoplasmosis
- Sarcoidosis
- Mets
- Silicosis
- EG
