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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