Chest Radiology in Intensive Care MedicineDr. Andrew Ferguson MEd FRCA DIBICM FCCPAssistant Professor, Medicine (Critical Care) & AnesthesiaDalhousie University: Chest Radiology in Intensive Care Medicine Dr. Andrew Ferguson MEd FRCA DIBICM FCCP Assistant Professor, Medicine (Critical Care) & Anesthesia Dalhousie University


Overview: Overview Air bronchograms & silhouette sign Hilar enlargement Alveolar & interstitial infiltrates Effusions Pulmonary oedema Assessment of volume status using CXR Lobar anatomy & collapse Abnormal air collections Lines, tubes and drains


Radiographic anatomy: Or LA Radiographic anatomy NOTE In spite of what you May have heard… The right heart border Is formed by left atrium in up to 38% of patients AV TV MV


Air bronchograms: Air bronchograms Bronchi normally invisible as they are thin-walled, filled with air, and surrounded by air Except when alveoli fill with substance with the density of fluid e.g. Pulmonary oedema Blood Gastric aspirate Inflammatory exudate Bronchi visible when surrounded by diseased lung = air bronchogram


Silhouette Sign: Silhouette Sign When an object is in contact with another of different density the adjoining edge is visible e.g. heart border against aerated lung When objects of the same density are in contact the adjoining edge is invisible e.g. heart border against consolidated lung


Silhouette Sign: Silhouette Sign


Hilar enlargement: Hilar enlargement Unilateral hilar adenopathy Neoplasm Primary Tuberculosis Sarcoidosis (3-8%) Primary pulmonary fungal infection Bilateral hilar adenopathy Sarcoidosis may also see right paratracheal nodes Lymphoma False positive Expiration film Pulmonary Hypertension


Alveolar infiltrates: Alveolar infiltrates What can fill alveoli? Water: pulmonary oedema Protein: ARDS, alveolar proteinosis Fibrous tissue: BOOP, radiation Cells: Neutrophils: pneumonia; pneumonitis Eosinophils: eosinophilic pneumonia RBCs: DAH, contusion, infarction, vasculitis Neoplastic: carcinoma, lymphoma, Lymphocytes: pneumonitis, sarcoidosis Air bronchograms “Fluffy” / indistinct appearance Segmental or lobar distribution Homogeneous & confluent


Rapid Clearance of Alveolar Infiltrate: Rapid Clearance of Alveolar Infiltrate Pulmonary oedema Pulmonary haemorrhage Aspiration Pneumococcal pneumonia (possibly)


Interstitial Infiltrates: Interstitial Infiltrates Inhomogeneous Discrete No bronchograms Reticular (lines) and/or Nodular (circles) Fibrosis Connective tissue disease Sarcoidosis Radiation fibrosis Asbestosis Lymphangitis carcinomatosis Silicosis TB


Pleural effusions: Pleural effusions


Pleural Effusion Appearances: Pleural Effusion Appearances Subpulmonic effusion Blunting of Costophrenic angle Meniscus sign Layering Loculated Laminar effusion Subpleural between lung & pleura Opacified hemithorax Air-fluid levels


Subpulmonic Effusion: Subpulmonic Effusion Tented diaphragmatic dome or apex more lateral than expected Costophrenic angle more shallow than expected Elevated diaphragm appears thicker and more separated from gastric bubble Usually < 350 ml volume


Blunting of Costo-phrenic Angle: Blunting of Costo-phrenic Angle 200-300 ml effusion required (AP film) 100-150 ml blunts posterior angle on lateral CXR


Pulmonary Oedema: Pulmonary Oedema


Pulmonary Oedema: Pulmonary Oedema ? Upper lobe diversion (“cephalization”) Infiltrates Batswing Diffuse Pleural effusions Septal lines e.g. Kerley B Basal, 1-2 cm long, straight, 90o to pleura Thickening of fissures Peribronchial cuffing Interstitial Oedema


Left atrial pressure & CXR signs: Left atrial pressure & CXR signs


Slide18: < 10% of cases of pulmonary oedema, usually in rapid onset oedema e.g. acute MR


Kerley B lines: Kerley B lines


Peribronchial Cuffing: Peribronchial Cuffing May be normal finding if right at hilum


Asymmetric pulmonary oedema: Asymmetric pulmonary oedema Chronic lung disease altering vascular flow Acute MR - jet to right pulm vein often RUL Patient position (gravitational) Re-expansion


Vascular Pedicle Width in Pulmonary Oedema: Vascular Pedicle Width in Pulmonary Oedema


Slide23: Martin, G. S. et al. Chest 2002;122:2087-2095 Landmarks for measurement of VPW and CTR on a routine CXR


Vascular pedicle width andfluid status in pulmonary oedema: Vascular pedicle width and fluid status in pulmonary oedema


Using Vascular Pedicle Width: Using Vascular Pedicle Width


VPW/CTR as predictor of PCWP > 18: VPW/CTR as predictor of PCWP > 18


Lobar anatomy and collapse: Lobar anatomy and collapse


Lobar anatomy & collapse: Lobar anatomy & collapse


RUL collapse: RUL collapse


RML collapse: RML collapse Indistinct right heart border


RLL collapse: RLL collapse Fissure may be visible Sail-like line behind right heart plus indistinct diaphragm


LUL Collapse: LUL Collapse Lufsichel sign = Aerated superior segment of left lower lobe interposes between collapsed upper lobe and mediastinum producing lucency around aorta


LLL collapse: LLL collapse Sail-like line behind heart – occasionally seen as extremely straight heart border


Total collapse: Total collapse


Abnormal Air Collections: Abnormal Air Collections Subcutaneous emphysema Pneumomediastinum Pneumothorax Pulmonary interstitial emphysema


Pulmonary Interstitial Emphysema: Pulmonary Interstitial Emphysema Much more common in neonates, rare in adults Alveolar rupture: air dissects into pulmonary interstitium Factors associated: Anything increasing intrapulmonary pressure Ventilation with peak airway pressures > 30 cm H20 RDS or ARDS severity Associated pulmonary abnormalities CXR features: subtle & often hidden by other pathology Multiple small and large parenchymal cysts Small, mottled or streaky lucencies extending from hilum Perivascular halos from air collections Intra-septal air Subpleural cysts


Pulmonary Interstitial Emphysema: Pulmonary Interstitial Emphysema


Pneumomediastinum: Pneumomediastinum Sources of air Intrathoracic Trachea and major bronchi Esophagus Lung Pleural space Extrathoracic Head and neck Intraperitoneum and retroperitoneum


CXR Signs of Pneumomediastinum: CXR Signs of Pneumomediastinum Thymic sail sign (infants/young children) Tubular artery sign (AP film) “Ring around the artery” sign (lateral film) Double bronchial wall sign Continuous diaphragm sign Extrapleural air Naclerio’s V sign Linear density parallel to heart border Dissection of air into neck Dissection of air into chest wall


Continuous diaphragm sign: Continuous diaphragm sign


Naclerio’s V sign: Naclerio’s V sign Lucent band of gas extending along descending aorta and intersecting band of gas that extends along medial left hemi- diaphragm, together forming “V’


Double bronchial wall sign: Double bronchial wall sign Air on both sides of bronchial wall makes full wall visible


“Ring around the artery” sign: “Ring around the artery” sign Air around pulmonary artery


Tubular artery sign: Tubular artery sign Air outlining left subclavian & left carotid


Thymic sail sign: Thymic sail sign Thymus outlined by air Also air tracking up into neck


Extrapleural air: Extrapleural air e.g. pleura peeled off diaphragm


Slide47: Mediastinal air


Slide48: Mediastinal air running parallel to descending aorta


Pneumomediastinum vs pneumothorax: Pneumomediastinum vs pneumothorax


Pneumomediastinum vs pneumocardium: Pneumomediastinum vs pneumocardium


Pneumopericardium: Pneumopericardium


Pitfalls – Mach band effect: Pitfalls – Mach band effect “The Mach band effect is associated with convex surfaces, appearing as a region of lucency adjacent to structures with convex borders. The absence of an (associated) opaque line, which is typically seen in pneumomediastinum, can aid in differentiation” Zylak C. Pneumomediastinum Revisited. Radiographics 2000; 20: 1043-1057.


Pneumothorax: Pneumothorax Apicolateral visceral pleural line Generally requires erect/semi-erect film Skin fold may be mistaken for pleural line Lack of lung markings outside line Caution in COPD/bullous disease Bullae generally convex ICU CXR often supine/semi-erect Different criteria for diagnosis Often subtle WATCH OUT!


“Occult” pneumothorax: “Occult” pneumothorax Crisp cardiac silhouette with increased lucency


Occult pneumothorax II: Occult pneumothorax II Cardiophrenic sulcus highly visible Crisp heart border


Potential signs of pneumothorax: Potential signs of pneumothorax Pleural line with absent markings Double diaphragm sign Visible anterior costophrenic recess interface Sharpened cardiac silhouette & apex Hyperlucent hemithorax Inferior edge of collapsed lung Deep sulcus sign Depressed diaphragm Apical pericardial fat Discrete lobulated densities (1-1 .5cm) adjacent to cardiac apex


Tension pneumothorax: Tension pneumothorax Flattening of heart border Flattening of adjacent vascular structures e.g. SVC Mediastinal shift - AWAY Diaphragmatic inversion


Double diaphragm sign: Double diaphragm sign


Pneumothorax in Supine Patients: Pneumothorax in Supine Patients Anteromedial - unusually sharp outline of: Mediastinal vascular structures Heart border Cardiophrenic sulcus Posteromedial Lucent band outlining mediastinal surface of a collapsed lower lobe Increased visibility of paraspinous line & descending aorta Increased visibility of posterior costophrenic sulcus Subpulmonic Hyperlucent upper abdominal quadrant Deep costophrenic sulcus (“deep sulcus” sign) Sharp hemidiaphragm despite opacification in lower lobe of lung (if consolidated) Visualisation of inferior surface of consolidated lung


Posteromedial Pneumothorax: Posteromedial Pneumothorax


Subpulmonic pneumothorax: Subpulmonic pneumothorax Deep sulcus, lucent RUQ Rankine, J. J et al. Postgrad Med J 2000;76:399-404


Anteromedial pneumothorax: Anteromedial pneumothorax Sharp outline of mediastinum and right heart border. Right hemithorax has concurrent consolidation and effusion Rankine, J. J et al. Postgrad Med J 2000;76:399-404


Mimics - Skin fold: Mimics - Skin fold


Subcutaneous emphysema: Subcutaneous emphysema


Lines, tubes and drains: Lines, tubes and drains


Central line positioning - issues: Central line positioning - issues Right upper heart border is left atrium, not the right, in 38% of patients Radiographic SVC/RA junction: hard to see in 10% inaccurate: can be up to 2.8 cm higher than echocardiographic junction not all lines within heart shadow on xray are in the RA CVC tip should lie in SVC above pericardial reflection (but no radiographic marker of this structure) BUT is acceptable for dialysis line tip to lie at SVC/RA junction or in RA Line should lie parallel to vessel wall Line tip < 2.9 cm beyond take-off of right main bronchus is always in SVC Right tracheobronchial angle is always below junction of brachiocephalic veins Carina is mean of 1.3 cm below mid-point of the SVC and up to 0.7 cm below pericardial reflection – is suitable location for line tip


Slide67: British Journal of Anaesthesia 2006 96(3):335-340


Slide68: Catheter tips abutting SVC wall – risk of perforation


Slide70: Malposition – subclavian line into jugular vein


Images to review: Images to review


Slide72: Asthma + diversion + peribronchial cuffing


Slide73: Right Haemothorax with bullet


Slide74: LUL collapse + LLL collapse


Slide75: Linear (plate) atelectasis + small bowel obstruction


Slide76: Bilateral hilar enlargement - lymphoma


Slide77: Bilateral cavitating lesions with fluid levels - Staph abcess


Slide78: Chilaiditi's syndrome – colon interspersed between liver/spleen and diaphragm


Slide79: Deep sulcus sign – left pneumothorax


Slide81: Diffuse alveolar haemorrhage


Slide82: Node in aortopulmonary window


Slide83: Fluid level behind heart – hiatus hernia


Slide84: Silicone breast implants


Slide85: Pneumothorax - blocked chest drain


Slide86: Subcutaneous emphysema, LIJ CVC tip position poor


Slide87: Residual haemothorax on left with chest tube and LLL collapse/consolidation + air bronchogram: haemothorax on right. Oesophagus displaced to left