The PA view Left chest appears on the right and Right chest on the left.
Distinguishing Right from Left Lung in the Lateral View. • Right ribs are posterior and Larger than left ribs. • The left hemi-diaphragm is hidden anteriorly by the heart. • The Right hemi-diaphragm extends to the right ribs- more posteriorly.
DIVERGENCE & MAGNIFICATION. The difference between the projector and the patient is 6 feet in the PA & 40 inches in the AP view.
The supine AP viewIn the AP supine film there is more equalization between the pulmonary vasculature of the upper and lower lobe & heart is enlarged.
The lateral decubitus • Pleural fluid volume. • Whether mobile / loculated. • Pneumothorax in a supine patient.
Inspiration 8-10 posterior ribs & 5-6 anterior ribs is adequate inspiration.
Penetration • In PA enough to just see disk spaces in thoracic spine, left hemi- diaphragm behind heart and vessels only up to 2/3 of lung area. • In lateral view 2 sets of ribs should be seen, sternum seen, spine appears clearer as it goes down.
RotationAssess by determining if clavicular heads are equidistant from spinous process of the thoracic vertebrae.
Lobes & Silhouette sign • Loss of lung/soft tissue interface. • Abnormality adjacent/anatomic contact. • Opacity in Posterior pleural cavity or posterior mediastinum or Right Lower lobe will cause OVERLAP but not an SILHOUTTE sign.
Air Bronchogram • A tubular outline of an airway visible due to alveolar filling/ collapse. • 6 causes- lung consolidation, pulmonary edema, non-obstructive pulmonary atelectasis, severe interstitial disease, neoplasm, and normal expiration.
Atelectasis -Collapse/ incomplete expansion. • Endobronchial– mucus plug/ tumor. • Extrinsic compression– mass/ effusion/ ascites. • Scarring-- post TB/ Radiation/ inflammation. • Linear/curved/wedge(apex-hilum) density with hilar/tracheal/media-stinal/diaphragm deviation with volume loss +/- compensatory hyper- inflation.
Pulmonary edema Batwing Bronchogram Cephalization Cardiomegaly Septal lines Effusion Cuffing
Major differentiating factors between atelectasis and pneumonia Atelectasis Pneumonia Volume Loss normal or increased volume Associated Ipsilateral Shift no shift/ contralateral shift Linear, Wedge-Shaped air space process Apex at Hilum not centered at hilum • Air bronchograms can occur in both.
Type of pneumonia • Lobar - entire lobe consolidated and air bronchograms common • Lobular - multifocal, patchy. • Interstitial - starts perihilar ,can become confluent and/or patchy as disease progresses, no air bronchograms • Aspiration pneumonia • Diffuse pulmonary infections - nosocomial (Pseudomonas, debilitated, mechanical vent, high mortality rate, patchy opacities, cavitation, immuno-compromised host(bacterial, fungal, PCP)
Hampton’s Hump Westermark Sign
OPACIFIED HEMITHORAX 1)Atelectasis, 2) pleural effusion, 3) Pneumonia, 4) pneumonectomy.
Unilateral pulmonary edema • Re-expansion • Venous obstruction • Dependent position • Bronchial obstruction • PE on the other side
Lung Masses Causes of lung nodules-by frequency Granulomas Bronchogenic ca Hamartoma Metastases Calcification Doubling time
Cavitating nodule Squamous cell most common Adenocarcinoma TB Abscess Mass with air bronchogram Alveolar cell ca Lymphoma Pseudolymphoma Inflammatory pseudotumor Types of bronchogenic carcinoma Squamous cell ca (30-35%) Adenocarcinoma (25-35%) Small cell or oat cell (25%) Large cell undifferentiated (10%)
Squamous cell - Central Location (2/3), Atelectasis, Post-obstructive pneumonia, May cavitate. Adenocarcinoma - Usually peripheral, Found in scars, Solitary nodule (52%), Upper lobe distribution (69%) Small cell- Mediastinal adenopathy, Hilar mass, Small or invisible lung nodule, High metastatic potential, Rapid growth. May be associated with Hypoglycemia, Cushing's syndrome, Inappropriate secretion of ADH, excessive gonadotropin secretion Large cell undifferentiated (10%) -Large peripheral mass, Pleural involvement
Roentgenographic findings Airway obstruction – Atelectasis, No air bronchogram, postobstructive pneumonia Hilar enlargement - From either the carcinoma itself or nodes, common in oat cell, uncommon in adenoca Mediastinal node enlargement -Particularly anaplastic ca Cavitation - 2-16% -Especially in squamous cell, mostly in upper lobes, Cavity is usually thick-walled with nodular inner margin Pleural involvement - 10%- Hemorrhagic effusion denotes direct tumor invasion , Effusion carries a poor prognosis even if no malignant cells are found