Chest Radiology in Intensive Care MedicineChest Radiology in Intensive Care MedicineDr. Andrew Ferguson Dr. Andrew Ferguson

MEd FRCA DIBICM FCCPMEd FRCA DIBICM FCCPAssistant Professor, Medicine (Critical Care) & AnesthesiaAssistant Professor, Medicine (Critical Care) & Anesthesia

Dalhousie UniversityDalhousie University

OverviewOverview

• Air bronchograms & silhouette signAir bronchograms & silhouette sign• Hilar enlargementHilar enlargement• Alveolar & interstitial infiltratesAlveolar & interstitial infiltrates• EffusionsEffusions• Pulmonary oedemaPulmonary oedema• Assessment of volume status using CXRAssessment of volume status using CXR• Lobar anatomy & collapseLobar anatomy & collapse• Abnormal air collectionsAbnormal air collections• Lines, tubes and drainsLines, tubes and drains

Or

LA

Radiographic anatomyRadiographic anatomy

NOTEIn spite of what youMay have heard…

The right heart borderIs formed by left atriumin up to 38% of patients

AV

TV

MV

Air bronchogramsAir bronchograms• Bronchi normally Bronchi normally invisibleinvisible as they are thin-walled, as they are thin-walled,

filled with airfilled with air, and , and surrounded by airsurrounded by air• Except when alveoli fill with substance with the Except when alveoli fill with substance with the

density of fluid e.g.density of fluid e.g.• Pulmonary oedemaPulmonary oedema• BloodBlood• Gastric aspirateGastric aspirate• Inflammatory exudateInflammatory exudate

• Bronchi visible when surrounded by diseased Bronchi visible when surrounded by diseased lung = lung = air bronchogramair bronchogram

Silhouette SignSilhouette Sign

• WhenWhen anan objectobject isis inin contactcontact withwith anotheranother ofof differentdifferent densitydensity thethe adjoiningadjoining edgeedge isis visiblevisible e.g.e.g. heartheart borderborder againstagainst aeratedaerated lunglung

• WhenWhen objectsobjects ofof thethe samesame densitydensity areare inin contactcontact thethe adjoiningadjoining edgeedge isis invisibleinvisible e.g.e.g. heartheart borderborder againstagainst consolidatedconsolidated lunglung

Silhouette SignSilhouette Sign

LobeLobe Silhouetted structureSilhouetted structure

Right middle lobeRight middle lobe Right heart borderRight heart border

Left lingulaLeft lingula Left heart borderLeft heart border

Right lower lobeRight lower lobe Right hemidiaphragmRight hemidiaphragm

Left lower lobeLeft lower lobe Left hemidiaphragmLeft hemidiaphragm

Post apical segment left upper lobePost apical segment left upper lobe Aortic knobAortic knob

Ant segment right upper lobeAnt segment right upper lobe Ascending aortaAscending aorta

Hilar enlargementHilar enlargementUnilateralUnilateral hilar adenopathy hilar adenopathy

Neoplasm Neoplasm Primary TuberculosisPrimary Tuberculosis Sarcoidosis (3-8%) Sarcoidosis (3-8%) Primary pulmonary fungal infection Primary pulmonary fungal infection

Bilateral Bilateral hilar adenopathyhilar adenopathy SarcoidosisSarcoidosis

may also see right paratracheal nodesmay also see right paratracheal nodes

Lymphoma Lymphoma False positive False positive

Expiration filmExpiration film

Pulmonary Hypertension Pulmonary Hypertension

Alveolar infiltratesAlveolar infiltrates

What can fill alveoli?What can fill alveoli?Water: pulmonary oedemaProtein: ARDS, alveolar proteinosisFibrous tissue: BOOP, radiationCells:

Neutrophils: pneumonia; pneumonitis Eosinophils: eosinophilic pneumoniaRBCs: DAH, contusion, infarction, vasculitisNeoplastic: carcinoma, lymphoma, Lymphocytes: pneumonitis, sarcoidosis

• Air bronchogramsAir bronchograms• ““Fluffy” / indistinct appearanceFluffy” / indistinct appearance• Segmental or lobar distributionSegmental or lobar distribution• Homogeneous & confluentHomogeneous & confluent

Rapid Clearance of Alveolar InfiltrateRapid Clearance of Alveolar Infiltrate

• Pulmonary oedemaPulmonary oedema• Pulmonary haemorrhagePulmonary haemorrhage• AspirationAspiration• Pneumococcal pneumonia (possibly)Pneumococcal pneumonia (possibly)

Interstitial InfiltratesInterstitial Infiltrates• InhomogeneousInhomogeneous• DiscreteDiscrete• NoNo bronchogramsbronchograms• ReticularReticular (lines)(lines) and/orand/or• NodularNodular (circles)(circles)

FibrosisFibrosis ConnectiveConnective tissuetissue diseasedisease SarcoidosisSarcoidosis RadiationRadiation fibrosisfibrosis AsbestosisAsbestosis LymphangitisLymphangitis carcinomatosiscarcinomatosis SilicosisSilicosisTBTB

Pleural effusionsPleural effusions

Pleural Effusion AppearancesPleural Effusion Appearances

• Subpulmonic effusion Subpulmonic effusion • Blunting of Costophrenic angle Blunting of Costophrenic angle • Meniscus sign Meniscus sign • Layering Layering • Loculated Loculated • Laminar effusionLaminar effusion

• Subpleural between lung & pleura Subpleural between lung & pleura

• Opacified hemithorax Opacified hemithorax • Air-fluid levels Air-fluid levels

Subpulmonic EffusionSubpulmonic Effusion• Tented diaphragmatic dome or apex more lateral than Tented diaphragmatic dome or apex more lateral than

expectedexpected• Costophrenic angle more shallow than expectedCostophrenic angle more shallow than expected• Elevated diaphragm appears thicker and more separated from Elevated diaphragm appears thicker and more separated from

gastric bubblegastric bubble• Usually < 350 ml volumeUsually < 350 ml volume

Blunting of Costo-phrenic AngleBlunting of Costo-phrenic Angle• 200-300 ml effusion required (AP film)200-300 ml effusion required (AP film)• 100-150 ml blunts posterior angle on lateral CXR100-150 ml blunts posterior angle on lateral CXR

Pulmonary OedemaPulmonary Oedema

Pulmonary OedemaPulmonary Oedema• ? Upper lobe diversion (“cephalization”)? Upper lobe diversion (“cephalization”)• InfiltratesInfiltrates

• BatswingBatswing• DiffuseDiffuse

• Pleural effusionsPleural effusions• Septal lines e.g. Kerley BSeptal lines e.g. Kerley B

• Basal, 1-2 cm long, straight, 90Basal, 1-2 cm long, straight, 90oo to pleura to pleura

• Thickening of fissuresThickening of fissures• Peribronchial cuffingPeribronchial cuffing

Interstitial Oedema

Left atrial pressure & CXR signsLeft atrial pressure & CXR signs

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

Kerley B linesKerley B lines

Peribronchial CuffingPeribronchial Cuffing

May be normal finding if right at hilum

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

Vascular Pedicle Width in Vascular Pedicle Width in Pulmonary OedemaPulmonary Oedema

Martin, G. S. et al. Chest 2002;122:2087-2095

Landmarks for measurement of VPW and CTR on a routine CXR

Vascular pedicle width andVascular pedicle width andfluid status in pulmonary oedemafluid status in pulmonary oedema

Using Vascular Pedicle WidthUsing Vascular Pedicle Width

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

CriteriaCriteria SensitivitySensitivity SpecificitySpecificity PPVPPV NPVNPV Odds ratioOdds ratio

VPW VPW >> 70 & CTR 70 & CTR >> 0.55 0.55 54%54% 83%83% 76%76% 65%65% 3.23.2

VPW VPW >> 70 70 69%69% 72%72% 70%70% 72%72% 2.52.5

CTR CTR >> 0.55 0.55 63%63% 50%50% 56%56% 57%57% 1.31.3

Lobar anatomy and collapseLobar anatomy and collapse

Lobar anatomy & collapseLobar anatomy & collapse

RUL collapseRUL collapse

RML collapseRML collapse

Indistinct right heart border

RLL collapseRLL collapse

Fissure may be visible Sail-like line behind right heart plus indistinctdiaphragm

LUL CollapseLUL Collapse

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

LLL collapseLLL collapse

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

Total collapseTotal collapse

Abnormal Air CollectionsAbnormal Air Collections

• Subcutaneous emphysemaSubcutaneous emphysema• PneumomediastinumPneumomediastinum• PneumothoraxPneumothorax• Pulmonary interstitial emphysemaPulmonary interstitial emphysema

Pulmonary Interstitial EmphysemaPulmonary Interstitial Emphysema• Much more common in neonates, rare in adultsMuch more common in neonates, rare in adults• Alveolar rupture: air dissects into pulmonary interstitiumAlveolar rupture: air dissects into pulmonary interstitium• Factors associated:Factors associated:

• Anything increasing intrapulmonary pressureAnything increasing intrapulmonary pressure

• Ventilation with peak airway pressures > 30 cm HVentilation with peak airway pressures > 30 cm H2200

• RDS or ARDS severityRDS or ARDS severity

• Associated pulmonary abnormalitiesAssociated pulmonary abnormalities

CXR featuresCXR features: subtle & often hidden by other pathology: subtle & often hidden by other pathology• Multiple small and large parenchymal cystsMultiple small and large parenchymal cysts

• Small, mottled or streaky lucencies extending from hilumSmall, mottled or streaky lucencies extending from hilum

• Perivascular halos from air collectionsPerivascular halos from air collections

• Intra-septal airIntra-septal air

• Subpleural cystsSubpleural cysts

Pulmonary Interstitial EmphysemaPulmonary Interstitial Emphysema

PneumomediastinumPneumomediastinum

• SourcesSources ofof airair– IntrathoracicIntrathoracic

TracheaTrachea andand majormajor bronchibronchi

EsophagusEsophagus

LungLung• PleuralPleural spacespace

– ExtrathoracicExtrathoracicHeadHead andand neckneck

IntraperitoneumIntraperitoneum andand retroperitoneumretroperitoneum

CXR Signs of PneumomediastinumCXR Signs of Pneumomediastinum

• ThymicThymic sailsail signsign (infants/young(infants/young children)children)

• TubularTubular arteryartery signsign (AP(AP film)film)

• ““RingRing aroundaround thethe arteryartery”” signsign (lateral(lateral film)film)

• DoubleDouble bronchialbronchial wallwall signsign

• ContinuousContinuous diaphragmdiaphragm signsign

• ExtrapleuralExtrapleural airair• NaclerioNaclerio’’ss VV signsign

• LinearLinear densitydensity parallelparallel toto heartheart borderborder• DissectionDissection ofof airair intointo neckneck• DissectionDissection ofof airair intointo chestchest wallwall

Continuous diaphragm signContinuous diaphragm sign

Naclerio’s V signNaclerio’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 signDouble bronchial wall sign

Air on both sides of bronchial wall makes full wall visible

““Ring around the artery” signRing around the artery” sign

Air around pulmonary

artery

Tubular artery signTubular artery sign

Air outlining left subclavian & left carotid

Thymic sail signThymic sail sign

Thymus outlinedby air

Also air trackingup into neck

Extrapleural airExtrapleural air

e.g. pleura peeled off diaphragm

Mediastinal air

Mediastinalair runningparallel to

descendingaorta

Pneumomediastinum vs pneumothoraxPneumomediastinum vs pneumothorax

Pneumomediastinum vs pneumocardiumPneumomediastinum vs pneumocardium

PneumopericardiumPneumopericardium

Pitfalls – Mach band effectPitfalls – Mach band effect

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

PneumothoraxPneumothorax

• Apicolateral visceral pleural lineApicolateral visceral pleural line• Generally requires erect/semi-erect filmGenerally requires erect/semi-erect film

• Skin foldSkin fold may be mistaken for pleural linemay be mistaken for pleural line

• Lack of lung markings outside lineLack of lung markings outside line• Caution in COPD/bullous diseaseCaution in COPD/bullous disease

• Bullae generally convexBullae generally convex

• ICU CXR often supine/semi-erectICU CXR often supine/semi-erect• Different criteria for diagnosisDifferent criteria for diagnosis

• Often subtleOften subtle

• WATCH OUT!WATCH OUT!

““Occult” pneumothoraxOccult” pneumothorax

Crisp cardiac silhouette with increased lucency

Occult pneumothorax IIOccult pneumothorax II

Cardiophrenic sulcus highly visible Crisp heart border

Potential signs of pneumothoraxPotential signs of pneumothorax

• PleuralPleural lineline withwith absentabsent markingsmarkings• DoubleDouble diaphragmdiaphragm signsign

• VisibleVisible anterioranterior costophreniccostophrenic recessrecess interfaceinterface

• SharpenedSharpened cardiaccardiac silhouettesilhouette && apexapex• HyperlucentHyperlucent hemithoraxhemithorax• InferiorInferior edgeedge ofof collapsedcollapsed lunglung• DeepDeep sulcussulcus signsign• DepressedDepressed diaphragmdiaphragm• ApicalApical pericardialpericardial fatfat

• Discrete lobulated densities (1-1 .5cm) adjacent to cardiac apex

Tension pneumothoraxTension pneumothorax

• Flattening of heart borderFlattening of heart border• Flattening of adjacent Flattening of adjacent

vascular structures e.g. SVCvascular structures e.g. SVC• Mediastinal shift - AWAYMediastinal shift - AWAY• Diaphragmatic inversionDiaphragmatic inversion

Double diaphragm signDouble diaphragm sign

Pneumothorax in Supine PatientsPneumothorax in Supine Patients

• AnteromedialAnteromedial - unusually sharp outline of: - unusually sharp outline of:

• Mediastinal vascular structuresMediastinal vascular structures

• Heart borderHeart border

• Cardiophrenic sulcusCardiophrenic sulcus

PosteromedialPosteromedial• Lucent band outlining mediastinal surface of a collapsed lower lobeLucent band outlining mediastinal surface of a collapsed lower lobe

• Increased visibility of paraspinous line & descending aortaIncreased visibility of paraspinous line & descending aorta

• Increased visibility of posterior costophrenic sulcusIncreased visibility of posterior costophrenic sulcus

SubpulmonicSubpulmonic• Hyperlucent upper abdominal quadrantHyperlucent upper abdominal quadrant

• Deep costophrenic sulcus (“deep sulcus” sign)Deep costophrenic sulcus (“deep sulcus” sign)

• Sharp hemidiaphragm despite opacification in lower lobe of lung (if consolidated)Sharp hemidiaphragm despite opacification in lower lobe of lung (if consolidated)

• Visualisation of inferior surface of consolidated lungVisualisation of inferior surface of consolidated lung

Posteromedial PneumothoraxPosteromedial Pneumothorax

Subpulmonic pneumothoraxSubpulmonic pneumothorax

Deep sulcus, lucent RUQ

Rankine, J. J et al. Postgrad Med J 2000;76:399-404

Anteromedial pneumothoraxAnteromedial pneumothorax

Sharp outline of mediastinum and right heart border. Right hemithoraxhas concurrent consolidation and effusion

Rankine, J. J et al. Postgrad Med J 2000;76:399-404

Mimics - Skin foldMimics - Skin fold

Subcutaneous emphysemaSubcutaneous emphysema

Lines, tubes and drainsLines, tubes and drains

Central line positioning - issuesCentral line positioning - issues• Right upper heart border is left atrium, not the right, in 38% of patients

• RadiographicRadiographic SVC/RASVC/RA junction:junction:• hardhard toto seesee inin 10%10%

• inaccurate:inaccurate: cancan bebe upup toto 2.82.8 cmcm higherhigher thanthan echocardiographicechocardiographic junctionjunction

• notnot allall lineslines withinwithin heartheart shadowshadow onon xrayxray areare inin thethe RARA

• CVCCVC tiptip shouldshould lielie• inin SVCSVC

• aboveabove pericardialpericardial reflectionreflection (but(but nono radiographicradiographic markermarker ofof thisthis structure)structure)

• BUTBUT isis acceptableacceptable forfor dialysisdialysis lineline tiptip toto lielie atat SVC/RASVC/RA junctionjunction oror inin RARA

• LineLine shouldshould lielie parallelparallel toto vesselvessel wallwall• LineLine tiptip << 2.92.9 cmcm beyondbeyond take-offtake-off ofof rightright mainmain bronchusbronchus isis alwaysalways inin SVCSVC• RightRight tracheobronchialtracheobronchial angleangle isis alwaysalways belowbelow junctionjunction ofof brachiocephalicbrachiocephalic veinsveins• CarinaCarina isis meanmean ofof 1.31.3 cmcm belowbelow mid-pointmid-point ofof thethe SVCSVC andand upup toto 0.70.7 cmcm belowbelow pericardialpericardial

reflectionreflection –– isis suitablesuitable locationlocation forfor lineline tiptip

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

Catheter tips abutting SVC wall – risk of perforation

Malposition – subclavian line into jugular vein

Images to reviewImages to review

Asthma + diversion + peribronchial cuffing

Right Haemothorax with bullet

LUL collapse + LLL collapse

Linear (plate) atelectasis+ small bowel obstruction

Bilateral hilar enlargement - lymphoma

Bilateral cavitating lesions with fluid levels- Staph abcess

Chilaiditi's syndrome – colon interspersed between liver/spleen

and diaphragm

Deep sulcus sign – left pneumothorax

Diffuse alveolar haemorrhage

Node in aortopulmonary window

Fluid level behind heart – hiatus hernia

Silicone breast implants

Pneumothorax - blocked chest drain

Subcutaneous emphysema, LIJ CVC tip position poor

Residual haemothorax on left with chest tube and LLL collapse/consolidation + air bronchogram: haemothorax

on right. Oesophagus displaced to left