[03.07] RAD - Chest Radiology V2.pdf

Streptococcus pneumoniae and Haemophilus influenzae

What are the typical pathogens associated with community-acquired pneumonia CAP?

Alveolus and terminal airway

What part of the respiratory system does community-acquired pneumonia primarily involve?

Alveolar transudation or edema

What pathological fluid processes are present in community-acquired pneumonia that lead to consolidation?

Consolidation and air bronchograms

What two major chest radiograph findings should be anticipated in community-acquired pneumonia?

Air within the consolidation that gets displaced in a retrograde manner

What is the definition of air bronchograms in the context of pneumonia?

Exudates fill the alveolar sacs displacing air retrogradely from the alveolus to the terminal bronchioles

What is the mechanical cause of air bronchograms?

Lucent points in the terminal bronchioles

How are air bronchograms seen visually on a chest radiograph?

Lobar opacification

What is the characteristic appearance of community-acquired pneumonia on a CT scan?

Consolidation

What does the term bronchogram indicate or represent when heard in chest imaging?

Upper lung lobe

In Figure 2 of the right lateral view of CAP, where is the consolidation specifically located?

Air bronchograms

In Figure 2 of the right lateral view of CAP, what do the subtle lucencies seen within the consolidation represent?

Staphylococcus aureus and Gram-negative bacteria

What are the primary pathogens associated with hospital-acquired pneumonia?

Airway

Where does hospital-acquired pneumonia typically begin before spreading to the alveoli?

Exudates in the airways accompanied by a concomitant volume loss

What causes the atelectasis seen in hospital-acquired pneumonia?

Nosocomial pneumonia

What is the alternative medical term for hospital-acquired pneumonia?

Multiple patchy opacities and volume loss or atelectasis

What are the expected chest radiograph findings in hospital-acquired pneumonia compared to community-acquired pneumonia?

More diffuse and bilateral

What is the typical appearance of hospital-acquired pneumonia on a CT scan?

Patchy areas

What general radiographic pattern is definitely indicative of pneumonia requiring clinical correlation to determine acquisition type?

Pattern recognition and clinical correlation such as whether the patient is already admitted

How do clinicians determine if pneumonia is community-acquired or hospital-acquired on chest imaging?

Diffuse patchy infiltrates

What is shown in Figure 4 on a chest radiograph of a pediatric patient with HAP?

Patchy opacities at the base of both sides of the lungs

What is the main finding in Figure 5?

Linear and thin region of the lung where exudates go

What is the definition and structural appearance of the lung interstitium?

Viruses and Mycoplasma pneumoniae

What are the primary pathogens associated with acute interstitial pneumonia?

Peribronchial areas

In acute interstitial pneumonia, where does inflammation occur due to pathogens attacking interstitial tissues rather than alveoli?

Bilateral spread

Is the spread of interstitial exudates in acute interstitial pneumonia typically unilateral or bilateral?

Viral etiology

What etiology is most commonly suspected by clinicians when an interstitial pattern is reported on imaging?

Peribronchial and interstitial streaky densities or opacities appearing over time

What are the delayed chest radiograph findings in acute interstitial pneumonia?

Inflamed interstitial tissue

What do the streaky densities seen on chest radiographs in acute interstitial pneumonia represent?

Bilateral reticular and interstitial opacities

What distinctive streaky appearance features emerge on a CT scan in acute interstitial pneumonia?

Ground glass opacification

What CT finding appears as hazy areas in the lungs indicating partial filling of air spaces or interstitial thickening?

Fine interstitial streak-like opacities indicated by pointed arrows

What is shown in the magnified lower right lung view of Figure 6?

Axial CT at lung bases showing prominent interstitial and ground glass opacities

What is shown in Figure 7?

Formation of cavities or hollow spaces in the lung tissue

What is the defining radiologic characteristic of cavitary pneumonia?

Necrosis of the lung parenchyma

What pathological process leads to the formation of cavitations?

Bronchial connections

What structural connection allows air and fluid to enter necrotic lung cavities?

Aspiration

What is the most common clinical event or cause leading to cavitary pneumonia?

Posterior segment of the right upper lung lobe

What is the most common anatomic location for cavitary pneumonia?

It is well aerated favoring the growth of air-loving tuberculous bacilli

Why does the posterior segment of the right upper lung lobe have a predilection for tuberculous and cavitary growth?

Anaerobes and Fungi

What are the common classes of pathogens associated with cavitary pneumonia?

Roughly spherical opacity

What is the basic visual appearance of a cavitary lesion on a chest radiograph?

Air fluid level

What radiological feature is visible on chest radiograph if a necrotic lung cavity is connected to a bronchus?

Round thick-walled opacity

What is the detailed CT scan appearance of a cavitary pneumonia lesion?

Surrounding inflamed and necrotic tissue

What do the thick walls of a cavitary lesion represent on CT scan?

Lucency representing air above and dependent fluid below separated by a horizontal line

What are the specific visual components of an air-fluid level within a cavity on a radiograph?

Cavitary lesion with fluid level pointed by an arrow in left lower lung lobe

What is shown in the left lung lateral view of Figure 9?

Liver

What structure does the diamond symbol represent in the axial chest CT scan at the lung bases of Figure 10?

Heart

What structure does the red heart symbol represent in Figure 10?

Cavitary lesion

What structure does the yellow circle outline in Figure 10?

Homogenous gray areas

How is lung consolidation represented visually on the CT scan in Figure 10?

Pockets of lucencies within the consolidations

How are cavities represented visually on the CT scan in Figure 10?

Hyperdense needle structure on the right side

What biopsy device is visualized performing a sampling in Figure 10?

An upper and a lower lobe only

What is the lobar anatomy of the left lung?

Major fissure

What anatomical landmark diagonally courses through the chest to separate the upper and lower lung lobes on a lateral view?

Pneumothorax and concomitant atelectasis

What are the major structural risks associated with puncturing the lung parenchyma during a needle-guided biopsy?

Free air compresses the lung immediately beside it

How does a pneumothorax lead to atelectasis during a lung puncture?

Biopsy

What is the definitive procedure required when laboratory results are inconsistent with the imaging pattern or when treatment is ineffective?

Radiologic patterns overlap and one pattern is not representative of a single etiology

Why can a biopsy be necessary to differentiate cavitations or other patterns on a chest radiograph?

Mycobacterium tuberculosis

What highly contagious pathogen is the causative agent of pulmonary tuberculosis?

Inhalation of air droplets coughed or sneezed by an infected person

How is pulmonary tuberculosis transmitted between individuals?

Apico-lordotic view

Which specialized chest radiograph view is utilized to clearly visualize the lung apices?

Primary and secondary

What are the two major clinical types of pulmonary tuberculosis infections?

Younger age group or pediatric patients

In what age group is primary tuberculosis most commonly seen?

Heals without complications

What is the typical clinical course of primary tuberculosis in many cases?

Small calcified granuloma that remains as a residual scar

What imaging trace is left after primary tuberculosis heals?

Pulmonary consolidation involving the lower lobes

What is the classic parenchymal chest radiograph finding in primary tuberculosis?

Basilar infiltrates

What term describes the increased areas of opacity typically located at the lung bases in primary tuberculosis?

Perihilar nodules

What radiographic finding represents swollen lymph nodes near the hilum in primary tuberculosis?

Caseous necrosis

What cheese-like form of cell death occurs in the affected lung tissue of pulmonary tuberculosis patients?

Two to ten weeks after initial infection

When does caseous necrosis typically manifest in pulmonary tuberculosis?

Lymphadenopathy particularly in the hilar regions

What is the common lymph node finding in pediatric patients with primary tuberculosis?

Abnormal opacities mostly at lung bases and perihilar lymph node prominence

What are the major chest radiograph findings of primary TB in Figure 11?

Perihilar nodularities marked by black arrows and abnormal basilar opacities

What does Figure 12 show on chest radiograph?

Post-primary tuberculosis

What is the alternative medical term for secondary tuberculosis?

Reactivation of a primary focus years after initial exposure

What is the pathogenesis of secondary tuberculosis?

Weakened immune systems such as from HIV infection malnutrition or aging

What patient factors predispose to the reactivation seen in secondary tuberculosis?

Adults

In what age demographic is secondary tuberculosis most commonly seen?

Apical and posterior segments of upper lung lobes

To which anatomical lung segments is secondary tuberculosis typically limited?

Upper lung areas are rich in oxygen which favors the growth of air-loving tuberculous bacteria

Why does secondary tuberculosis localize to the upper lung lobes?

Patchy or confluent infiltrates in the upper lung lobes

What is the primary parenchymal finding of secondary tuberculosis on a chest radiograph?

Sharp linear opacities radiating towards the hilum

What radiographic feature represents fibrotic changes or inflamed bronchovascular structures in secondary tuberculosis?

Forty percent

In what percentage of cases does secondary tuberculosis present with cavitations?

No adenopathy

What lymph node finding distinguishes secondary tuberculosis from primary tuberculosis?

Atelectasis pulling structures close to it

What is the mechanism behind the upward traction of the hila in secondary tuberculosis?

Pulmonary nodules or granulomas

What term describes the round opacities of varied sizes and shapes seen on a secondary tuberculosis CT scan?

Consolidation in the upper lung zone

What is the most obvious finding on the chest radiograph of Figure 13?

Volume loss with upward traction of the hila and round thick-walled cavitations

What are the main findings on the CT scan in Figure 13?

Upper and lower lung zones

What lung zones are involved in the more advanced pulmonary TB case of Figure 14?

Irreversible dilatation of the bronchi

What structural airway abnormality characterizes bronchiectasis?

Destruction of the elastic and muscle tissue of the bronchial wall

What pathological destruction leads to bronchiectasis?

Recurring pneumonia and hemoptysis

What are the two key clinical presentations of bronchiectasis?

Cylindrical or tubular varicose and cystic or saccular

What are the three morphological categories of bronchiectasis?

Tramline parallel linear shadows

What classic chest radiograph finding represents the thickened walls of dilated bronchi in bronchiectasis?

High-resolution CT scan HRCT

What is the imaging modality of choice for diagnosing bronchiectasis?

Signet ring sign

What CT sign is present when a cross-section of a dilated bronchus appears larger than its accompanying pulmonary vessel?

Outer third of the lung

In what region of the lung parenchyma can dilated bronchi be visualized on CT to help diagnose bronchiectasis?

Linear tubular lucencies

What does Figure 15 show on chest radiograph?

Branching lucencies indicated by an arrow

What does HRCT of bronchiectasis in Figure 16 display?

Varicose-type bronchiectasis

What specific morphologic type of bronchiectasis is shown in the CT of Figure 17?

Clinical diagnosis

What type of diagnosis is chronic bronchitis based on symptom history?

Excessive mucus formation and cough for more than three months in two straight years

What clinical history criteria are required to diagnose chronic bronchitis?