Radiology Flashcards
Differential diagnosis for round pneumonia?
• pulmonary masses o bronchogenic cyst o neuroblastoma o type III CCAM o pulmonary metastases o pleural fibroma o fungal infection o pulmonary sequestration
What is tree in bud appearance on CT?
- describes the CT appearance of multiple areas of centrilobular nodules with a linear branching pattern
- can be due to disease in distal airways (at the level of bronchiole, small airway disease) or distal vasculature
- usually due to endobronchial spread of infection
- Invasive pulmonary aspergillosis
- TB - endobronchial spreading
- NTM
- ABPA
Causes of centrilobular nodules?
- things that enter lung through airway can give centrilobular nodules
- Hpersensitivity pneumonitis
- Infection - TB, mycoplasma
Is you see an area of opacification on CT, what are the 2 terminology descriptions?
- Consolidation: ● Increase in lung opacity obscuring vessels, may see air bronchograms since air can still be present in airways
- Ground glass opacification: ● Hazy increase in lung opacity without obscuration of underlying vessels
What is crazy paving and differential diagnosis for crazy paving?
Ground glass superimposed on septal thickening
Differential:
- PAP
- Infection like PJP (which can also cause PAP)
- ARDS
- diffuse alveolar hemorrhage
- organizing pneumonia
- lipoid pneumonia
What is the difference between high attenuation versus low attenuation lesion on CT scan?
- High attenuation - something that is occupying and displacing air and appears white–>opacity
- Low attenuation - increased air content, appears black –>lucency
What are signs of bronchiectasis on CT?
- bronchus visualised within 1 cm of pleural surface
* especially true of lung adjacent to costal pleura * most helpful sign for early cylindrical change * lack of tapering * increased bronchoarterial ratio 9
* diameter of a bronchus should measure approximately 0.65-1.0 times that of the adjacent pulmonary artery branch * between 1 and 1.5 may be seen in normal individuals, especially those living at high altitude * greater than 1.5 indicates bronchiectasis
A number of ancillary findings are also recognised:
*
bronchial wall thickening: normally wall of bronchus should be less than half the width of the accompanying pulmonary artery branch
*
mucoid impaction
*
air-trapping and mosaic perfusion
Signs described on CT include: * tram-track sign * signet ring sign
Causes of diffuse cystic lung disease?
- lymphangioleiomyomatosis (these women often get pneumothorax)
- Birt-Hogg-Dubé syndrome
- pulmonary Langerhans cell histiocytosis
- desquamative interstitial pneumonia
- lymphocytic interstitial pneumonitis (LIP, which is associated with HIV)
PJP
(I think BPD could also be on this list, Filamin A mutation)
Differential diagnosis for honeycombing?
● Fibrosis ○ IPF/UIP ○ RA, scleroderma ○ Drug reaction ○ End-stage HP ● End-stage sarcoidosis
Differential diagnosis for mediastinal lymphadenopathy?
● Lymphoma
● Infection: TB, histoplasmosis
● Sarcoidosis (symmetric)
● Silicosis
Other: pneumonia, scleroderma
Differential diagnosis for anterior, middle and posterior mediastinal mass?
- Anterior: posterior sternum to pericardium. Thymoma, termatoma, lymphoma, goitre
- Middle mediastinum: anterior pericardium to ventral surface of thoracic spine. Lymphadenopathy, bronchogenic cyst, esophageal tumor, vascular mass/enlargement
- Posterior (spine): meningocele, neuroblastoma, gastroenteric duplication cyst (can present in infants and there can be associated vertebral anomalies)
- foregut duplication cyst is a more generic name for cysts, including bronchogenic cyst and enteric cyst
Differential diagnosis for hyperlucency and mediastinal shift on an infant’s CXR?
- pneumothorax
- congenital lobar emphysema
- CPAM
- absence of contralateral lung
- CDH
Other:
- PIE (there would be a pattern of hyerlucency in the interstitium, but I’m not sure if there would be mediastinal shift)
- foreign body
Radiopedia:
bronchial atresia: the parenchyma distal to the atretic segment can have air trapping
congenital pulmonary airway malformation (CPAM)
pulmonary arterial hypoplasia
pulmonary hypoplasia
Swyer-James syndrome - unilateral BO, the affected lung is hyperinflated and hyperlucent
filamin A mutation
Other:
Air: pneumothoax, pneumonectomy
Obstruction: * foreign body * airway obstruction - endobronchial TB, carcinoid, mucous plug * Swyer James
Unilateral large bullae
Differential diagnosis for unilateral diaphragm elevation on imaging?
Above the diaphragm
- Atelectasis
- Pulmonary hypoplasia
- Prior lobectomy and pneumonectomy
- diaphragmatic hernia
- Sub-pulmonic effusion (between lung and diaphragm)
Within the diaphragm
- Diaphragm eventration
- Diaphragm paralysis - tumor, viral infection like HSV, surgical injury
Below the diaphragm
- Abdominal mass
- Sub-phrenic abscess
- Distended colon or stomach
What is a ground glass opacity? Differential diagnosis?
increased attenuation, but you can still see bronchial and vascular markings
- it could be due to alveolar process (due to partial filling or collapse, in contrast to consolidation) or could be an interstitial process
- Infection:
- PJP
- Viral - CMV, RSV, influenza, paraflu
(you generally aren’t thinking of a typical bacterial pneumonia with ground glass, these would usually cause consolidation) - Drug toxicity
- Alveolar - ARDS, edema, TRALI, DAH
- interstitial diseases–COP, eosinophilic pneumonia, sarcoid
Differential diagnosis for pulmonary consolidation?
- fill up alveoli
- common to get associated air bronchograms
- typical infection
- edema
- PAP
- ARDS
- lipoid pneumonia
- aspiration pneumonia
- DAH
- other: COP, eosinophilic pneumonia