Part 1 Ventilation-Perfusion Lung Scan
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Transcript of Part 1 Ventilation-Perfusion Lung Scan
Lung Scan Lung Scan &&
RdnRdn. . VenographyVenography
Jiraporn Jiraporn SriprapapornSriprapaporn, M.D., M.D.Nuclear MedicineNuclear MedicineSiriraj HospitalSiriraj HospitalMahidolMahidol UniversityUniversityThailandThailand
Copy Right By J Sriprapaporn
Part 1-Lung Scan_J SRIPRAPAPORN
ContentsContents--2 parts2 parts
AnatomyAnatomyPhysiologyPhysiologyMechanism Mechanism
TechniqueTechniqueIndicationsIndicationsInterpretationInterpretation
Part 2. Radionuclide Part 2. Radionuclide venographyvenography
Part 1. V/Q Lung scansPart 1. V/Q Lung scans
PART 1PART 1
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RespiratoryRespiratory SystemSystem
Perfusion lung scanPerfusion lung scan:: TcTc--9999m MAAm MAA
Ventilation lung scanVentilation lung scan:: XeXe--133,133, TcTc--9999m m aerosolaerosol,, TechnegasTechnegas
MucociliaryMucociliary clearanceclearance:: TcTc--9999m HSAm HSA
Lung epithelial permeabilityLung epithelial permeability:: TcTc--9999m m DTPADTPA
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AnatomyAnatomy
Right lung Right lung && left lungleft lungBronchopulmonaryBronchopulmonarysegments segments ((arteryartery,, veinvein,, && bronchusbronchus))
RightRight LungLung:: 33 lobeslobes;;RULRUL,,RMLRML,, && RLLRLLLeft LungLeft Lung:: 22 lobeslobes;; LUL LUL ((LingularLingular segmentssegments)) && LLLLLL
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BronchopulmonaryBronchopulmonary SegmentsSegments
1.1. LUL LUL AnteriorAnteriorApicoApico--posteriorposteriorLingularLingular :: SuperiorSuperior
: Inferior: Inferior
2.2. LLL LLL Superior Superior Anterior basalAnterior basalLateral basalLateral basalPosterior basalPosterior basal
1.1. RUL RUL AnteriorAnteriorApicalApicalPosteriorPosterior
2.2. RMLRMLMedialMedialLateralLateral
3.3. RLL RLL Superior Superior Anterior basalAnterior basalLateral basalLateral basalPosterioPosterio basal basal
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BloodBlood SupplySupply
22 SystemsSystems::
Pulmonary arteriesPulmonary arteries::95%95%
BronchialBronchial arteriesarteries:: 5%5%
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PhysiologyPhysiology
AIRAIR RespiratoryRespiratory tracttract:: tracheatrachea----bronchibronchi--bronchiolesbronchioles alveolialveoliFunctionFunction:: Gas exchangeGas exchangeDistribution of Q Distribution of Q && V from apex to base is V from apex to base is unevenuneven in in the upright position the upright position ((gravity effectgravity effect))Gravity effects the distribution of both Q Gravity effects the distribution of both Q && V V ((affects affects perfusion perfusion >> ventilationventilation))
TOPBOTTOM
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Ventilation & Perfusion DistributionVentilation & Perfusion Distribution
Modified from West, J.B., Ventilation/Blood Flow and Gas Exchange, Oxford, 1977.
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EffectsEffects oof f GravityGravity((UprightUpright PositionPosition))
APEX VENTILATION PERFUSIONPERFUSION V/Q RATIO
BASE 1.5-2 folds 33--55 foldsfolds
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PathophysiologyPathophysiology
Ventilation abnormality Ventilation abnormality redistributionredistribution of of pulmonary perfusion pulmonary perfusion HypoventilationHypoventilation reflex vasoconstriction reflex vasoconstriction hypoperfusionhypoperfusion
AcuteAcute hypoperfusionhypoperfusion rarelyrarely produces produces hypoventilationhypoventilation or minimalor minimal;; not clinically not clinically significantsignificant
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LungLung ScaScann
PERFUSIONPERFUSION LUNGLUNG SCANSCAN ((QQ))TcTc--9999m m MAAMAA
VENTILATIONVENTILATION LUNGLUNG SCANSCAN ((VV))XeXe--133,133, XeXe--127,127, KrKr-- 8181mmTcTc--9999m m DTPADTPA// phytatephytate aerosolaerosolTechnegasTechnegas
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IndicationsIndications of of VV//Q Q LungLung ScanScan
AAcute pulmonary embolismcute pulmonary embolism**
Pulmonary hypertensionPulmonary hypertension
PPriorrior to thoracic surgeryto thoracic surgery
RightRight--toto--left shuntleft shunt
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Pulmonary EmbolismPulmonary Embolism
Most important complication of DVTMost important complication of DVTSymptomatic, Symptomatic, fatal*fatal*Asymptomatic (silent)Asymptomatic (silent)
Origin: Leg DVT (70Origin: Leg DVT (70--80%)80%)
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DIAGNOSIS OF PULMONARY EMBOLISMDIAGNOSIS OF PULMONARY EMBOLISM
ClinicalsClinicals :: Inaccurate Inaccurate ((dyspneadyspnea, chest pain, , chest pain, hemoptysishemoptysis))Lab tests Lab tests :: DD--dimerdimerArterial Blood GasesArterial Blood Gases:: HypoxemiaHypoxemia,, AA--A A gradientgradientECG ECG :: Classic SClassic S11QQ33TT33 pattern pattern CXR CXR :: Normal or mild Normal or mild abnabn (*(*RR//OO otherotherdiseasesdiseases))VV//Q lung scan Q lung scan :: V/Q mismatched defectsV/Q mismatched defectsCTPA (CT Pulmonary CTPA (CT Pulmonary ArteriographyArteriography))PulmonaryPulmonary AngiographyAngiography****** Gold standardGold standardOthersOthers:: MRMRAA
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ClinicalClinical DiagnosisDiagnosis oof Pf PEE
SymptomsSymptoms::Clinical TriadClinical Triad::DyspneaDyspnea(shortness of (shortness of breath)breath), , pleuriticpleuriticchest painchest pain,,hemoptysishemoptysisDyspneaDyspnea,,tachypneatachypnea,, coughcough,,chest painchest pain,, cardiac cardiac arrythmiaarrythmia,, syncopesyncope
SignsSigns::Increased HRIncreased HR,, AFAF,,RRRR,, hypotensionhypotension,,pleural rubpleural rub,, PP22
WELLS SCORE Pretest clinical probability assessment. [Wells PS, et al. Thromb Haemost. 2000 Mar;83(3):416-20.]
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ChestChest RadiographRadiograph ((CCXRXR))
AtelectasisAtelectasis andand//or or parenchymalparenchymal opacity opacity (51%)(51%)Pleural effusion within the affected Pleural effusion within the affected hemithoraxhemithorax (35%)(35%)FleischnerFleischner''s signs sign ((regional regional oligemiaoligemia in the in the presence of an presence of an ipsilateralipsilateral enlarged PAenlarged PA))WestermarkWestermark''s signs sign ((local pulmonary local pulmonary oligemiaoligemia,,11%11% of of hemithoraceshemithoraces with PEwith PE))HamptonHampton’’ss humphump ((a wedgea wedge--shaped pleural shaped pleural based densitybased density,, 23%23% of of hemithoraceshemithoraces withwith PEPE))
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DD--dimerdimerFibrin degradation product Fibrin degradation product
SensitivitSensitivity 90y 90--9595%, %, NOT NOT specifispecific !c !High NPVHigh NPV;; negative results negative results with with ELISA testsELISA tests effectively effectively rule out DVT or PErule out DVT or PE..
Different techniques Different results !
•The diagnostic yield of D-dimer relies on its specificity, which variesaccording to patient characteristics.
•The specificity of D-dimer in suspected PE decreases steadily withage and may reach 10% in patients above 80 years.81
•D-dimer is also more frequently elevated in patients withcancer,82,83 in hospitalized patients84 and during pregnancy.85,86
European Heart Journal 2008 29(18):2276-2315
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MultidetectorMultidetector Pulmonary CTAPulmonary CTA
CTPACTPA showingshowing multiplemultiplefillingfilling defectsdefects ofof principalprincipalbranchesbranches ofof thethepulmonarypulmonary arteriesarteries,, duedue totoacuteacute andand chronicchronic PE.PE.Rad. Exposure Rad. Exposure
CTPA = 8CTPA = 8--10 10 mSvmSvV/Q = 2 V/Q = 2 mSvmSv
Sensitivity of CTA = 83 Sensitivity of CTA = 83 %, specificity = 96%, specificity = 96 %% [Stein PD & PIOPED II_NEJM 2006]
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Samuel Z Goldhaber , Henri BounameauxPulmonary embolism and deep vein thrombosis The Lancet Volume 379, Issue 9828 :2012;1835 - 1846
http://dx.doi.org/10.1016/S0140-6736(11)61904-1
Figure 1 A diagnostic algorithm for clinically suspected deep Figure 1 A diagnostic algorithm for clinically suspected deep vein vein thrombosis or pulmonary embolism Use of CUS with suspected DVT thrombosis or pulmonary embolism Use of CUS with suspected DVT and of MDCT angiography with PE. CUS=compression and of MDCT angiography with PE. CUS=compression ultrasonographyultrasonography. .
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Table 2. Performance of some tests or diagnostic Table 2. Performance of some tests or diagnostic algorithms to rule in or rule out PE algorithms to rule in or rule out PE
Likelihood ratio (95% CI)Likelihood ratio (95% CI)
To rule in PETo rule in PE
HighHigh--probability V/Q lung probability V/Q lung scintigraphyscintigraphy 1818··3 (103 (10··33––3232··5)5)
Positive CTAPositive CTA 2424··1 (121 (12··44––4646··7)7)
Positive proximal vein CUS of the legPositive proximal vein CUS of the leg 1616··2 (52 (5··66––4646··7)7)
To rule out PETo rule out PE
Normal or near normal ventilation perfusion lung Normal or near normal ventilation perfusion lung scintigraphyscintigraphy 00··05 (005 (0··0303––00··10)10)
Negative CTA (mainly single detector)Negative CTA (mainly single detector) 00··11 (011 (0··0606––00··19)19)
Negative CTA and proximal vein CUS of the legNegative CTA and proximal vein CUS of the leg 00··04 (004 (0··0303––00··06)06)
Negative proximal vein CUS of the legNegative proximal vein CUS of the leg 00··67 (067 (0··5050––00··89)89)
Quantitative ELISA DQuantitative ELISA D--dimerdimer assay less than 500 assay less than 500 μμgg/L/L 00··08 (008 (0··0404––00··18)18)
Goldhaber SZ 2012
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PerfusionPerfusion LungLung ScanScan::PrinciplePrinciple
Tracer: TcTracer: Tc--99m MAA, particle 99m MAA, particle size=10size=10--30 u30 uMechanism: Mechanism: Capillary blockadeCapillary blockade --lodged in lodged in pprecapillaryrecapillaryarteriolesarterioles in proportion to regional blood flowin proportion to regional blood flowNumber of particlesNumber of particles::
Minimum = 100,000Minimum = 100,000Optimum = Optimum = 200,000200,000--600,000600,000
About About 1/10001/1000 ( 0.1 %)( 0.1 %) capillaricapillarieses are blocked are blocked Biological T Biological T 1/21/2 in the lungs in the lungs == 22--44 hr hr RERE systemsystem
Defects from PE
// bronchopulmonarysegments
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ReducedReduced NumberNumber oof f ParticlesParticles InjectedInjected
Pediatric patientsPediatric patientsSuspected or known Suspected or known RRtt--toto--LLt shuntt shuntSevere pSevere pulmonary hypertensionulmonary hypertensionPrior pneumonectomyPrior pneumonectomySingle lung transplantSingle lung transplant100,000 to 200,000 particles100,000 to 200,000 particles
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PerfusionPerfusion LungLung ScanScan::TechniquesTechniques
Dose: TcDose: Tc--99m MAA 99m MAA 33--5 5 mCimCiInjectInjection:ion: in in supinesupine positionpositionมม avoid avoid injecting via the indwelling catheter port injecting via the indwelling catheter port containing a filtercontaining a filterDo not draw blood into syringeDo not draw blood into syringe;;
““hot spotshot spots”” in in Q Q lunglung scanscan******StaticStatic planarplanar images images 66--88 viewsviews,, 500500 kctskctsSPECT imagingSPECT imaging
Critical organ = lungs
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MultipleMultiple hothot spotsspots in Qin Q llungung sscancan
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VentilationVentilation LungLung ScanScan::PrinciplePrinciple
Gas: most physiologic !Gas: most physiologic !ParticleParticles:s: ssmaller maller sizesize deeperdeeper!!TracersTracers
Inert gasInert gas:: 133133XeXe,, 127127XeXe,, 8181mmKrKrAerosolAerosol** (0.5 u)(0.5 u):: 9999mmTcTc--DTPADTPA// phytatephytateTechnegasTechnegas:: TcTc--9999m aerosol particle sizem aerosol particle size::0.02-0.2um
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VentilationVentilation AgentsAgents
Xe-133 Xe-127 Kr-81m Tc-99m radioaerosol
Technegas/ Pertechnegas
T1/2 5.3d 36.4d 13s 6h 6h
γ energy 80 203 190 140 140
Status Gas Gas Gas Aerosol (0.5-3 um)
Gas-like (0.02-0.2 um)
Cost Low High High Low High
Before/After Q scan
B A A B B
Multiple V N N Y Y Y
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TECHNEGAS TECHNEGAS vsvs PERTECHNEGASPERTECHNEGAS
Burning 99mTcO4- in a carbon
crucible at high TempUltrafine radiolabeledaerosol (0.02-0.2um)Is purged with 5%O2 + 95%argonMore penetrate alv epithelial membraneShorter residence time in the lungTbio = 6-10 min
Burning 99mTcO4- in a carbon crucible at high TempUltrafine radiolabeledaerosol (0.02-0.2um)Is purged with 100%argonLittle transalveolar or mucociliary ClearanceLonger residence time in the lungTbio = 6 hr.
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VentilationVentilation LungLung ScanScan::TechniquesTechniques
Patient preparationPatient preparation:: NoneNonePatient cooperation: YesPatient cooperation: YesTechniquesTechniques::
InhalationInhalation,, upright position is upright position is preferredpreferred..
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XeXe--133133 VentilationVentilation LungLung ScanScan
Single view-3 phases: Washin-Equilibrium-Washout
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XeXe--133133 Ventilation Lung ScanVentilation Lung Scan
Single view, 3 phases:WashinEquilibriumWashout : most sensitive to diagnose obstructive airway disease
Xenon is fat soluble uptake in the liver refers to fatty liver.
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RadioRadio--aerosolaerosolVentilationVentilation LungLung ScanScan
O2
• Imaging of multiple views
• Relatively large particles central airway deposition !
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RadioRadio--aerosol aerosol Ventilation Lung ScanVentilation Lung Scan
TcTc--99m DTPA aerosol can 99m DTPA aerosol can cross alveolar capillary cross alveolar capillary membranemembrane shorter residence time as shorter residence time as compared to Tccompared to Tc--99m sulfur colloid aerosol. [half 99m sulfur colloid aerosol. [half time is about 1 hr.]time is about 1 hr.]
Only 2Only 2--10% of administered radioactivity goes to 10% of administered radioactivity goes to the lungs. [30 the lungs. [30 mCimCi 11--2 2 mCimCi]]
Central depositionCentral deposition of the radioactivity is common of the radioactivity is common inin COPD.COPD.
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TECHNEGASTECHNEGAS
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TechnegasTechnegas VentilationVentilation ScanScan
• Ultrafine particles
• Ideal for ventilation lung SPECT
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FigureFigure 1.1. NNormalormal VV//Q Q SPECTSPECT.. usingusing TechnegasTechnegasandand 9999mTcmTc--MAAMAA arearealignedaligned andand displayeddisplayed inintransversetransverse,, coronalcoronal andandsagittalsagittal planesplanes
Roach PJ, et al SNM08
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InterpretationInterpretation oof f LungLung ScanScan
1.1. Pretest clinical probabilityPretest clinical probability2.2. PerfusionPerfusion Lung Scan Lung Scan ((QQ))3.3. VentilationVentilation Lung Scan Lung Scan ((VV))4.4. CXRCXR ((within within 1212--2424 hrshrs))
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NormalNormal LungLung ScanScan
Uniform distribution Uniform distribution of the radioactivityof the radioactivity
No VNo V//Q defectQ defect
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1.1. NonuniformNonuniform distributiondistribution
2.2. Perfusion andPerfusion and// or ventilation or ventilation defectdefectNNonsegmentalonsegmental defectdefectSegmentalSegmental defectdefect:: wedgedwedged--shapedshaped && pleuralpleural--basedbased defectdefect
LargeLarge defectdefect:: >> 75%75% ofof segmentsegmentModerateModerate defectdefect:: 2525--75%75% ofofsegmentsegmentSmallSmall defectdefect:: << 25%25% ofof segmentsegment
AbnormalAbnormal LungLung ScanScan
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V/Q Match V/Q Match vsvs MismatchMismatch
VV//Q matched defectQ matched defect:: AbnAbn both Q both Q && VV
VV//Q mismatch defectQ mismatch defect:: AbnAbn QQ,, Normal VNormal V
Pulmonary Embolism
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Segmental Segmental NonNon--segmentalsegmental
Pulmonary embolismPulmonary embolismPulmonary infarctPulmonary infarct
TumorsTumorsPleuralPleural effusioneffusionCardiomegalyCardiomegalyMediastinalMediastinal oror hilarhilaradenopathyadenopathyPneumoniaPneumoniaBullaeBullaeMetalMetal artifactsartifacts
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NonNon--PEPE DiseasesDiseases//ConditionsConditions
PatchyPatchy distributiondistributionNonsegmentalNonsegmental defectdefectMatchedMatched VV//Q Q defectdefect((ss))CausesCauses egeg.. metallicmetallic artifactartifact,, enlargedenlarged LNLN,,tumortumor,, heartheart,, pneumoniapneumonia,, effusioneffusion
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VV//Q Q MatchedMatched AbnormalitiesAbnormalities
COPDCOPDBlebsBlebs,, bullaebullaePulmonary edemaPulmonary edema,, CHFCHFPleural effusionPleural effusionAsthmaAsthmaPulmonary traumaPulmonary traumaMucous plugMucous plugBronchogenicBronchogenic CACA
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V/Q Mismatches: CausesV/Q Mismatches: Causes
Acute PEAcute PEPrevious PEPrevious PEBronchogenicBronchogenic carcinomacarcinomaVasculitisVasculitisPrevious radiation therapyPrevious radiation therapyPulmonary vascular Pulmonary vascular anormaliesanormalies
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InterpretationInterpretation oof f AcuteAcute PPEE
““PIOPED CRITERIAPIOPED CRITERIA””NormalNormal RR//O significant O significant PEPE !!-- likelihood of likelihood of PE < 5%PE < 5%Very low probability: Very low probability: < 10%< 10%LowLow probabilityprobability :: << 20%20%IntermediateIntermediate :: 2020--80%80%HighHigh probabilityprobability:: >> 80%.80%. AtAt least least 22 large large segmental mismatched Vsegmental mismatched V//Q defectsQ defects,,negative CXRnegative CXR
PIOPED " The Prospective Investigation of Pulmonary Embolism Diagnosis "
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PIOPEDPIOPED
"" The Prospective Investigation The Prospective Investigation ofof Pulmonary Pulmonary EmbolismEmbolism Diagnosis Diagnosis ““Used pulmonary angiogram as a gold Used pulmonary angiogram as a gold standard.standard.
TheThe criteria were developed in late criteria were developed in late 19831983The largest study of accuracy of lung scan in The largest study of accuracy of lung scan in
the the DxDx of acute PEof acute PE66 medical centers in Umedical centers in U..SS..AA..
PIOPED II CTA PIOPED III MRA
PIOPED I V/Q Lung scan
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Original PIOPED CriteriaOriginal PIOPED CriteriaHigh Probability:High Probability:
> 2 large segmental perfusion defects> 2 large segmental perfusion defects without corresponding ventilation or without corresponding ventilation or roentgenographicroentgenographic abnormalities or substantially larger than either matching ventabnormalities or substantially larger than either matching ventilation ilation or CXR abnormality. or CXR abnormality. > 2 moderate segmental perfusion defects without corresponding v> 2 moderate segmental perfusion defects without corresponding ventilation or entilation or roentgenographicroentgenographic abnormalities and 1 large mismatched segmental defect. abnormalities and 1 large mismatched segmental defect. > 4 moderate segmental perfusion defects without ventilation or > 4 moderate segmental perfusion defects without ventilation or CXR abnormalities. CXR abnormalities.
Intermediate probability (indeterminate):Intermediate probability (indeterminate):Not falling into normal, veryNot falling into normal, very--lowlow--, low, low--, or high, or high--probability categories. probability categories. Borderline high or borderline low. Borderline high or borderline low. Difficult to categorize as low or high. Difficult to categorize as low or high.
Low probability:Low probability:NonsegmentalNonsegmental perfusion defects perfusion defects Single moderate mismatched segmental perfusion defect with normaSingle moderate mismatched segmental perfusion defect with normal CXR l CXR Any perfusion defect with a substantially larger CXR abnormalityAny perfusion defect with a substantially larger CXR abnormality. . Large or moderate segmental perfusion defects involving no more Large or moderate segmental perfusion defects involving no more than 4 segments in than 4 segments in 1 lung and no more than 3 segments in 1 lung region with matchin1 lung and no more than 3 segments in 1 lung region with matching ventilation defects g ventilation defects either equal to or larger in size and chest roentgenogram eithereither equal to or larger in size and chest roentgenogram either normal or with normal or with abnormalities substantially smaller than perfusion defects. abnormalities substantially smaller than perfusion defects. >3 small segmental perfusion defects with a normal >3 small segmental perfusion defects with a normal
Very low probability:Very low probability:<3 small segmental perfusion with a normal CXR.<3 small segmental perfusion with a normal CXR.
Normal:Normal:No perfusion defects No perfusion defects NOTE:CXR=chest roentgenogram. NOTE:CXR=chest roentgenogram. JAMA 1990
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VV//Q Q Lung ScanLung Scanfforor DetectionDetection oof Pf PEE oon Pn PAGAG
ProbabilitProbability y BielloBiello McNeilMcNeil PIOPED PIOPED BielloBiello McNeilMcNeil PIOPEDPIOPED
HighHigh 5757 5353 4141 9090 9191 9797HighHigh//IntermInterm.. 6969 6161 8282 7575 7979 5252HighHigh//IntermInterm.. 9797 9898 9898 5151 5151 1010
//LowLow
Sensitivity Specificity
[Worsley DF et al. Radiologic Clinics of N America 1993]
NB. High number of intermediate prob., 39% of the total populationstudied (364 of 931), while 68% of the subjects were inpatients.[Freeman LM SNM 2008]
PPV
81%
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V/Q Lung ScanV/Q Lung Scan
High High probprobNPV = 91%NPV = 91%PPV = 81% for all types of PtsPPV = 81% for all types of Pts
PPV = 91% for Pts without prior PEPPV = 91% for Pts without prior PEPPV = 74% for Pts with prior PEPPV = 74% for Pts with prior PE
Low Low probprobNPV = 84% NPV = 84% Low Low probprob VQ VQ ++veve PE in 15% of Pts.PE in 15% of Pts.Thus, should not Thus, should not misinterpretemisinterprete lowlow--probprob lung lung
scan as R/O PEscan as R/O PE
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PPVPPV oof Vf V//Q Q LungLung ScanScaniin n DiagnosisDiagnosis oof Pf PEE
Clinical Probability
Scan Category 80-100% 20-79% 0-19%
High 95% 85% 83%
Intermediate 71% 29% 14%
Low 43% 16% 4%
Normal/NN 0% 7% 2%
[PIOPED JAMA 1990, Sostman HD Radiology 1994]
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Ventilation-Perfusion Scintigraphy in thePIOPED Study. Part II. Evaluation of theScintigraphic Criteria and Interpretations
we recommend that 3 criteria should be reconsidered:1. A single moderate perfusion defect is appropriately
categonzed as intermediate, rather than as lowprobability.
2. Extensive matched V/Q abnormalitiesare appropriatefor low probability, provided that the CXR is dear.Single-matched defect may be better categonzed asintermediate probability. [small number of cases].
3. 2 segmental mismatches may not be the optimumthreshdd for high probability, and in some casesshould be considered for intermediate probability.[small number of cases]
Gottschalk A, et al. J NucIMed1993;34:1119-1126
Revised PIOPED V/Q Scan Criteria
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Ventilation-Perfusion Scintigraphy in thePIOPED Study. Part II. Evaluation of theScintigraphic Criteria and Interpretations
Gottschalk A, et al. J Nucl Med 1993;34:1119-1126 PMID: 8315488
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Revised paper_by Sostman Radiology 1994
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AIM:AIM:To compare original, revised PIOPED & gestalt To compare original, revised PIOPED & gestalt interpretation.interpretation.
RESULTS:The gestalt probability estimate was the most accurate forassessing the likelihood of PE. [area under the ROC curve0.836]The revised PIOPED criteria (area under the ROC curve =0.753) were more accurate than the original PIOPEDcriteria.
CONCLUSION:The revised PIOPED criteria are more accurate than theoriginal PIOPED criteria.Experienced readers of lung scans can achieve highestaccuracy
Sostman HD Radiology 1994; 193:103-107
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DefDef:: a matching perfusiona matching perfusion,, ventilationventilation,,and CXR abnormalityand CXR abnormality
UpperUpper && middle lung zones middle lung zones ==Very lVery lowow probprobof PE of PE (4%)(4%) [[Stein PD & Gottschalk A. RadioGraphics January 2000:20;99-105]]
Lower Lower lung zonelung zone == Intermediate Intermediate probprob of PE of PE (33%)(33%)
[[WorsleyWorsley DFDF,, AlaviAlavi AA.. J J NuclNucl MedMed 1995;1995; 36:36: 23802380--23872387WorsleyWorsley DFDF,, et alet al.. J J NuclNucl MedMed 1993;1993; 34:34: 18511851--1853]1853]
TRIPLETRIPLE MATCHMATCH
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""Stripe SignStripe Sign"" == A thin line A thin line ((stripestripe)) of activity of activity ((perfusionperfusion))at the pleural surface of a Q defectat the pleural surface of a Q defect..
The finding is associated is likely related to The finding is associated is likely related to spared perfusion in the cortex of the lungspared perfusion in the cortex of the lung[[SostmanSostman HDHD,, GottschalkGottschalk AA.. Radiology Radiology 19921992 ]]
""Stripe SignStripe Sign"" is suggested to is suggested to indicateindicate very very lowlow probabilityprobability == 7%7% of lung zones with the of lung zones with the stripe sign stripe sign had PEhad PE present on PAG in the present on PAG in the PIOPED study PIOPED study [[GottschalkGottschalk AA,, et alet al.. J J NuclNucl MedMed 1993]1993]
STRIPESTRIPE SIGNSIGN
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Low Low probprob misleading due to sig. PE misleading due to sig. PE prevprev
VV//Q Lung Scan ClassificationQ Lung Scan Classification
Stein PD & Gottschalk A. RadioGraphics January 2000:20;99-105
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785§6Stripe sign
427‡1Triple matched defect in the upper or middle lung zone
168†11-3 small segmental Q defects
330*1Matched V/Q defects in 2 or 3 zones of a single lung (normal radiograph)
840*3Q defect smaller than corresponding radiographic defect
8103*8Nonsegmental perfusion abnormality
PPV(%)No. of Patients,
Lungs, or Lung Zones or Regions
No. of Cases of PE
Criterion
*Individual lungs were evaluated. †Patients were evaluated.‡Lung zones were evaluated §Lung regions were evaluated.
CriteriaCriteria forfor VeryVery--llowow ProbabilityProbabilityInterpretationInterpretation ofof VQVQ LungLung ScansScans
Stein PD & Gottschalk A. RadioGraphics January 2000:20;99-105
PPV < 10 %
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Causes of Decreased Perfusion Causes of Decreased Perfusion to One Lungto One Lung
Pulmonary agenesis or Pulmonary agenesis or stenosisstenosisSwyerSwyer--James syndromeJames syndromeEmbolusEmbolusPneumothoraxPneumothoraxMassive pleural effusionMassive pleural effusionMediastinalMediastinal fibrosisfibrosisTumorTumor
Part 1-Lung Scan_J SRIPRAPAPORN
TypicalTypical ScintigraphicScintigraphicFindingsFindings ForFor PEPE
Multiple segmental Multiple segmental perfusion defectsperfusion defectsNormal ventilationNormal ventilationUsually normal Usually normal CXRCXR
““MismatchMismatcheded VV//Q Q defectsdefects””
Part 1-Lung Scan_J SRIPRAPAPORN
ResolutionResolution ofof Q Q DefectDefectssiin n AcuteAcute PEPE
First First 22 weeksweeks rapidrapid resolutionresolution,, then slower then slower over the next over the next 33 MoMo33%33% of of PtsPts with major emboli have perfusion with major emboli have perfusion defects beyond defects beyond 1212 MoMoThe resolution is slower with increasing age The resolution is slower with increasing age &&in the presence of cardiovascular disease in the presence of cardiovascular disease ((Tom Tom && Wagner Wagner 1967)1967)15-35% of Pts have recurrent PE with in the first yr.
Part 1-Lung Scan_J SRIPRAPAPORN
ResolutionResolution oof f PerfusionPerfusion DefectDefect
Q Defect 2 Wk 3 Wk 4 Wk Recover
4 Mo
Improve
4 Mo
Small 40% 67% 75%
Moderate 30% 38% 51%
Severe 20% 20% 70%
Note: Small: <15%, Moderate 15-30%, Severe >30% reduced pulmonary blood flow (Tom & Wagner 1967)
Part 1-Lung Scan_J SRIPRAPAPORN
PPulmonaryulmonary EEmbolismmbolism::Before & After AnticoagulantBefore & After Anticoagulant RxRx
Part 1-Lung Scan_J SRIPRAPAPORN
AcuteAcute PulmonaryPulmonary EmbolismEmbolism
PerfusionPerfusion--Ventilation lung scan Ventilation lung scan ******Multiple mismatched VMultiple mismatched V//Q defects Q defects ((segmentalsegmental),),No radiographic abnormalityNo radiographic abnormalityIncreasing noIncreasing no.. of defects of defects increasingincreasingspecificityspecificityPulmonary Pulmonary angiographyangiography is the gold standardis the gold standard..VV//Q scan cannot Q scan cannot DDxDDx acute from chronic PEacute from chronic PE,, so so FF//U scan to evaluate the lung status post Rx U scan to evaluate the lung status post Rx ****** ((Baseline for the new episodeBaseline for the new episode,, if anyif any))
Part 1-Lung Scan_J SRIPRAPAPORN
PulmonaryPulmonary HypertensionHypertensionDef: Mean Def: Mean pulmpulm arterial P > 25 mmHgarterial P > 25 mmHgCauses of PHT: PPHT (idiopathic, Causes of PHT: PPHT (idiopathic, chrchr thromboembolicthromboembolic, left , left heart disease, heart disease, pulmpulm parenchymalparenchymal disease)disease)PrimaryPrimary PHTPHT
Idiopathic PHTIdiopathic PHT,, small small vvvv..,, obliterativeobliterativeDxDx by exclusion criteriaby exclusion criteriaLung scanLung scan:: NonsegmentalNonsegmental patchy Q defect patchy Q defect
ThromboembolicThromboembolic PHTPHTLarge Large vvvvTTreatablereatable
VV//Q lung scan canQ lung scan can help help DxDx thromboembolic PHT thromboembolic PHT (found < (found < 5% of PHT cases)5% of PHT cases)
SenSen > CTA;> CTA; sensen > 96%, spec 95%, accuracy 95%> 96%, spec 95%, accuracy 95%
Part 1-Lung Scan_J SRIPRAPAPORN
PE in ThailandPE in Thailand
PalwatwichaiPalwatwichai AA,, et alet al.. J J MedMed AssocAssoc ThaiThai.. 20002000
Retrospective review oRetrospective review of 49f 49 patients patients diagnoseddiagnosedas PE in Phramongkutklao as PE in Phramongkutklao HospHosp.. betweebetween n 1994 and 19981994 and 1998The mortality rate The mortality rate wawas 10%.s 10%.Chronic Chronic thromboembolicthromboembolic pulmonary HT was pulmonary HT was diagnosed idiagnosed in 12%n 12% of the patientsof the patientsHighHigh--probability VQ lung scanprobability VQ lung scan and and DVTDVT were were demonstrated idemonstrated in 93%n 93% anand 55%d 55%,, respectivelyrespectively..
Part 1-Lung Scan_J SRIPRAPAPORN
PE in ThailandPE in Thailand
Prevalence of pulmonary embolism in Prevalence of pulmonary embolism in patients with deep venous thrombosis patients with deep venous thrombosis ((MangkharakMangkharak et al.)et al.)
Prospective study of 48 cases with proven Prospective study of 48 cases with proven leg DTVleg DTV
1212 cases cases (25%)(25%) had highhad high--probprob lung scanlung scan77 cases cases (58%)(58%) -- No No respresp symptomsymptom((asymptomaticasymptomatic PEPE))55 cases cases (42%)(42%) -- with with respresp symptom symptom ((symptomatic PEsymptomatic PE))
Part 1-Lung Scan_J SRIPRAPAPORN
VV//Q Q LungLung ScanScan fforor DxDx PEPE
ADVANTAGES VS DISADVANTAGESADVANTAGES VS DISADVANTAGES
SimpleSimple,, noninvasivenoninvasive,,safesafe,, and economicaland economicalHigh specificityHigh specificity (98%)(98%)espesp.. increasing noincreasing no.. of of defects defects The usefulness is well The usefulness is well documenteddocumented..
Not widely availableNot widely availableMinimal radiationMinimal radiationLow sensitivity Low sensitivity (41%)(41%)Limitation in Limitation in abnabn CXRCXRVV//Q scan cannot Q scan cannot DDxDDxacute from chronic PE acute from chronic PE
needneed FF//U scanU scan
Part 1-Lung Scan_J SRIPRAPAPORN
IsIs FollowFollow--upup LungLung ScanScan UsefulUseful ??
Because resolution of Q defect may not be completeBecause resolution of Q defect may not be complete,,depending on defect sizedepending on defect size,, durationduration,, also Ptalso Pt’’s age s age &&underlying cardiovascular diseases underlying cardiovascular diseases ((Tom Tom && Wagner Wagner 1967)1967) [33%[33% of of PtsPts with major emboli have perfusion with major emboli have perfusion defects beyond defects beyond 1212 MoMo]]And And 1515--35%35% of of PtsPts have recurrent PE with in the first have recurrent PE with in the first yryr..Since VQ lung scan cannot Since VQ lung scan cannot DDxDDx new or old emboli new or old emboli FF//U VU V//Q scan at least at Q scan at least at 33 MoMo is useful as the is useful as the baseline for the next episodebaseline for the next episode.. ((slower resolution slower resolution occurs after occurs after 33 MoMo))
That’s why we need F/U lung scan ?
Part 1-Lung Scan_J SRIPRAPAPORN
Part 1-Lung Scan_J SRIPRAPAPORN
ApplicationsApplications ffororNonNon--embolicembolic LungLung DisordersDisorders
RRightight--toto--lefleftt shunt shunt ******Prior thoracic surgeryPrior thoracic surgery:: Lung cancerLung cancer,,Other lung diseasesOther lung diseasesLung transplantationLung transplantationInflammatory lung diseasesInflammatory lung diseasesOthersOthers
Part 1-Lung Scan_J SRIPRAPAPORN
RRightight--toto--LLefteft SShunthunt
Intracardiac shuntIntrapulmonary shunt
Through Through pulmpulm AV fistulasAV fistulasTiny Tiny abnabn,, difficult to demonstrate by difficult to demonstrate by angiographyangiographyProduce Produce hypoxemiahypoxemia,, && assoasso with with significant significant intraopintraop.. && POPO.. risk risk Relative CRelative C//I to liver transplantI to liver transplant
Part 1-Lung Scan_J SRIPRAPAPORN
RightRight--toto--left Shuntleft ShuntSystemic Circulation
Part 1-Lung Scan_J SRIPRAPAPORN
Presence of Presence of TcTc--9999m m MAA in the systemic MAA in the systemic circulationcirculation;; brain brain &&kidneyskidneys
TechniqueTechnique:: Limited MAA Limited MAA particlesparticles..
LungLung ScanScan iin n RtRt--toto--LLt t ShuntShunt
Part 1-Lung Scan_J SRIPRAPAPORN
PriorPrior ThoracicThoracic SurgerySurgery
Quantitative lung function study Quantitative lung function study Geometric mean: Geometric mean: √√CCANTANT . . CC POSTPOST
Equivocal lung function test Equivocal lung function test ((egeg. FEV1, FVC). FEV1, FVC)
ToTo evaluate regional lung function and evaluate regional lung function and predict residual lung function post surgical predict residual lung function post surgical resectionresection
Lung cancerLung cancerOther lung Other lung diseasesdiseases
Part 1-Lung Scan_J SRIPRAPAPORN
QuantitativeQuantitativeLungLung FunctionFunction StudyStudy
FIGURE 12FIGURE 12.. Quantitative Quantitative perfusion scan perfusion scan Large perfusion defect from Large perfusion defect from tumor on posterior image tumor on posterior image ((arrowarrow).).LLeft lung contributes eft lung contributes 30.6%30.6%and right lung and right lung 69.4%69.4% of total of total pulmonary function pulmonary function ((arrowheadsarrowheads).).HenceHence,, it is anticipated that it is anticipated that removal of left lung will removal of left lung will result in decrease of result in decrease of approximately approximately 30%30% of total of total pulmonary functionpulmonary function..
JNMT March 2009 vol. 37 no. 1 1-13
Part 1-Lung Scan_J SRIPRAPAPORN
WellsWells PSPS.. PulmonaryPulmonary embolismembolism::a a clinicianclinician''s s perspectiveperspective..
SeminSemin NuclNucl MedMed.. 20082008 NovNov;38(6):404;38(6):404--11.11.
....... Diagnostic strategies should include pretest clinicalprobability,D-dimer assays, and imaging tests.
Approaches that use CTPA or V/Q scanning appear equally safe, buteach approach hasadvantages and disadvantages that should beappreciated to provide the best care.
Importantly, patients at low risk with a negative D-dimer can avoidimaging tests
V/Q scanningmay be more appropriate in premenopausal women,in those with renal dysfunctionor diabetes, in those with knowncontrast allergies, and perhaps in patients withknown familyhistory of breast cancer.
Part 1-Lung Scan_J SRIPRAPAPORN
Prof Leonard M. FreemanMontefiore Medical CenterAlbert Einstein College of MedicineBronx, New York
•VQ Scan as a primary examination•VQ scan as a F/U study
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Part 1-Lung Scan_J SRIPRAPAPORN
VQVQ ScanScan asas a a primaryprimary examinationexamination
DrawbacksDrawbacks withwith usingusing MDCTAMDCTA forfor SuspectedSuspected1.1. ContrastContrast--relatedrelated
ContrastContrast AllergyAllergyNephrotoxicityNephrotoxicity
2.2. InstrumentInstrument--relatedrelatedClaustrophobiaClaustrophobiaObesityObesity
3.3. RadiationRadiation exposureexposure--relatedrelatedChildrenChildrenPregnantPregnant womenwomen--fetusfetusYoungYoung womenwomen--breastbreast tissuetissue
2/4
Part 1-Lung Scan_J SRIPRAPAPORN
VQVQ scanscan asas a Fa F//U U studystudyIt is most beneficial to follow all positive CT studies with abaseline V/Q study for the purpose of long-term follow-up.
DDx old vs new clot facilitate such importantdecisions.
A baseline V/Q study should be routinely performed inpatients with DVT since the incidence of silent PE is about38% or greater.
In a DVT patient who has been anticoagulated and,subsequently, presents with suspected PE judge whetherthe embolus has occurred before or after the start of theanticoagulation.
If the PE was present at the time of DVT diagnosis,continuation of anticoagulant therapy will suffice. (besufficient)If the latter IVC ‘‘umbrella’’ procedure may bewarranted. 3/4
Part 1-Lung Scan_J SRIPRAPAPORN
ConclusionConclusion
1. It is the responsibility of the imaging physician to beknowledgeable about the relative value and the benefit-to-riskratio of each procedure to properly advise the referring physician.
2. Most medical centers do not offer ‘‘after hours’’ nuclear medicineservices on nights and weekends while there is 24-h readyavailability of CT scanners prefer MDCT
3. It is my belief that a plain CXR can be useful to determine which procedure should be performed* Normal or near-normal CXR V/Q scan* Abnormal CXR MDCTA.
4. It also is the inherent responsibility of all radiologists and NMphysicians to educate our referring clinicians about the excessiveradiation exposure associated with MDCTA, particularly to thefemale breast.
4/4
Part 1-Lung Scan_J SRIPRAPAPORN
SummarySummaryMultidetector CTA and V/Q lung scintigraphy are bothexcellent imaging examinations to evaluate patients withsuspected PE.Because of the much greater radiation exposure,particularly to the female breast, associated with CTA, itis desirable to use V/Q imaging when possible.The major problem causing difficulty in interpreting V/Q studies is underlying pulmonary disease, such aspneumonia, significant atelectasis, pleural effusions, andchronic obstructive lung disease. If abnormal CXR,directing to a CTA.Most importantly, it is the responsibility of the imagingphysician to be knowledgeable about the relative valueand the benefit-to-risk ratio of each procedure toproperly advises the referring physician.
Part 1-Lung Scan_J SRIPRAPAPORN
WellWell’’ss CriteriaCriteria forfor PEPE:: Program CalculationProgram Calculation
httphttp://://wwwwww..mdcalcmdcalc..comcom//wellswells--criteriacriteria--forfor--pulmonarypulmonary--embolismembolism--pepe
Part 1-Lung Scan_J SRIPRAPAPORN
Suggested ReadingSuggested Reading
Essentials of Nuclear Medicine ImagingEssentials of Nuclear Medicine Imaging
The Requisites: Nuclear MedicineThe Requisites: Nuclear Medicine
Part 1-Lung Scan_J SRIPRAPAPORN
Lung Scan v4_SNM Guideline Mar 2012
Continue for part 2.Continue for part 2.
Radionuclide Radionuclide VenographyVenography