Med Imaging: Lungs Pt 2

Bronchiectasis

Definition: thickening of the walls of the bronchi due to inflammation or infection. Can be diffuse or focal

Cause: chronic or severe infection damaging the bronchial cartilage (irreversible)

Common Pathogens: Klebsiella, S Aureus, Mycobacterium TB, Mycoplasma pneumo, nonTB mycobacteria, measles, pertussis, influenza, RSV, HSV, adenovirus

Associated Conditions: cystic fibrosis, allergic bronchopulmonary aspergillosis

Bronchiectasis CXR

often normal or shows nonspecific findings. Later signs include tram-tracking and honeycomb infiltrates in the medial aspects of lower lobes

Bronchiectasis CT Scan

preferred method, clearly shows bronchiectasis

Blebs and Bullae

Definition: lung tissue w/ air space but no alveoli (non-functioning)

Bleb: < 1 cm in diameter

Bullae: > 1 cm, often much larger

Blebs and Bullae: CXR

difficult to see, may appear as absence of pulmonary markings

Blebs and Bullae: CT Scan

easily seen

COPD/Emphysema

Definition: chronic obstructive pulmonary disease, a clinical dx

COPD/Emphysema: CXR

not indicated unless symptoms exacerbate. Normal in early stages, signs of hyperinflation in advanced stages

Signs: flattening of hemidiaphragms, blunting of costophrenic angles, inc AP diameter, presence of bullae or large air cavities

Atelectasis

Definition: complete or partial collapse of the lung or a lobe

Cause: no air reaching the alveoli due to obstruction, compression, fibrosis, or loss of surface tension

Types: liner (discoid or plate-like) - often seen post-op

Atelectasis: CXR

confirms atelectasis, differentiates from air-space opacification

Atelectasis: CT Scan

may be needed to determine the cause

Asthma: CXR

usually not indicated in acute exacerbations. Long-standing may show interstitial patterns due to scarring or mild bronchiectasis

Pneumothorax

air in the pleural space causing lung collapse. Seen as an area of no vascularity and a thin white line on CXR

Pleural Effusion

fluid in the pleural space. Causes include CHF, pneumonia, pancreatitis, cirrhosis, malignancy

Pleural Effusion: CXR

upright shows costophrenic angle blunting, lateral decubitus shows fluid along the lateral chest wall

Pleural Effusion: CT Scan

indicated for suspect loculated effusion or empyema

Empyema

Pus in the pleural space. Appears elliptical and can be loculated. Best visualized w/ CT scan

Pleural Calcifications & Masses

result from old calcified empyema or asbestosis. Mesothelioma may appear as a focal pleural mass

Diaphragmatic Rupture

Cause: usually due to trauma, more common on the left side

Imaging: loops of bowel in the lower chest cavity, best seen on CXR

Hemoptysis

Coughing up blood. CXR indicated if true hemoptysis

Chest pain or Dyspnea

CXR indicated if exam is abnormal or pt is over 40 or at risk for CVD

Hypertension

CXR not needed for routine follow-up but may be useful in new onset w/ tobacco use Hx or symptomatic cases

CHF

CXR indicated for Dx and progression. Shows progressive changes from normal to pulmonary edema

Mediastinal Lesions

Definition: lesions in the mediastinum, can be focal or diffuse, anterior, middle, posterior

Imaging: CT scan or MRI w/ contrast is always indicated. MRI preferred for neurogenic lesions

Epiglottis

Definition: inflammation of the epiglottis

Causes: infectious (H influenza type B, group A B-hemolytic Strep, TB) or inflammatory (sarcoidosis)

Anterior lesions

Thymoma, thyroid lesions, teratoma, T-cell lymphomas, lymphadenopathy

Middle lesions

Thoracic aortic aneurysms, hematomas, neoplasms, lymphadenopathy, esophageal lesions, diaphragmatic hernias

Posterior lesions

Neurogenic lesions, hiatal hernias, descending aortic aneurysm, neoplasms, hematomas