MSCTMSCTPotential Benefits and Potential Benefits and

LimitsLimitsAntoine Sarkis, MD

Associate Professor of Cardiology

Hôtel Dieu de France Hospital

MSCT is a major innovative technique for non-MSCT is a major innovative technique for non-invasive detection of coronary artery stenosesinvasive detection of coronary artery stenoses

► 129 patients129 patients► Compare the diagnostic accuracy of multislice CT Compare the diagnostic accuracy of multislice CT

and MRIand MRI► Sensitivity for detection of clinically significant Sensitivity for detection of clinically significant

coronary stenoses (> or =50%): 82 %coronary stenoses (> or =50%): 82 %► Specificity: 90Specificity: 90► Negative predictive value: 95 %Negative predictive value: 95 %

Ann Intern Med. 2006 Sep 19;145(6):466-7.

Potential IndicationsPotential Indications

►MSCT in asymptomatic personsMSCT in asymptomatic persons►MSCT in highly suspected Coronary MSCT in highly suspected Coronary

artery diseaseartery disease►MSCT in known Coronary artery MSCT in known Coronary artery

disease: follow-up of graft patency, disease: follow-up of graft patency, stentsstents

MSCT in asymptomatic persons: MSCT in asymptomatic persons: 1st Scenario: Normal CT1st Scenario: Normal CT

► Normal CT in a person with no or minimal risk factors for Normal CT in a person with no or minimal risk factors for CADCAD

►Good news, but was-it a surprise? Was the CT really needed?Good news, but was-it a surprise? Was the CT really needed?

MSCT in asymptomatic persons:MSCT in asymptomatic persons:2nd Scenario: Plaque or mild to moderate 2nd Scenario: Plaque or mild to moderate

stenosisstenosis► This patient has risk factors, he is asymptomatic, but This patient has risk factors, he is asymptomatic, but

CT shows ~ 50% stenosis on LAD and RCA.CT shows ~ 50% stenosis on LAD and RCA.

►What is the next step?What is the next step?

MSCT in asymptomatic persons:MSCT in asymptomatic persons:2nd Scenario: Plaque or mild to moderate 2nd Scenario: Plaque or mild to moderate

stenosisstenosis

LAD

RCA

LAD

►What is the next step?What is the next step?

MSCT in asymptomatic persons:MSCT in asymptomatic persons:2nd Scenario: Plaque/or mild to moderate 2nd Scenario: Plaque/or mild to moderate

stenosisstenosis

►This patient had cardiac cath, then This patient had cardiac cath, then cardiac scintigraphy, exactly the inverse cardiac scintigraphy, exactly the inverse classical way of screening classical way of screening asymptomatic patientsasymptomatic patients

►He received a total of 36 mSvHe received a total of 36 mSv►Knowing he has multiple risk factors, did Knowing he has multiple risk factors, did

CT add information to his status?CT add information to his status?►Final treatment: Statins, Aspirin, Final treatment: Statins, Aspirin,

AnxiolyticsAnxiolytics

MSCT in asymptomatic persons:MSCT in asymptomatic persons:3rd scenario: severe disease3rd scenario: severe disease

MSCT in asymptomatic persons:MSCT in asymptomatic persons:3rd scenario: severe disease3rd scenario: severe disease

LAD

RCA

MSCT in asymptomatic persons:MSCT in asymptomatic persons:3rd scenario: severe disease3rd scenario: severe disease

►Couldn’t we identify this patient by Couldn’t we identify this patient by non invasive testing: Stress test with non invasive testing: Stress test with or without nuclear imaging or echo?or without nuclear imaging or echo?

MSCT in asymptomatic persons:MSCT in asymptomatic persons:4th Scenario: massive calcium4th Scenario: massive calcium

56 yrs old man, smoker, dyslipidemia, hypertension

MSCT as a screning test?MSCT as a screning test?ProPro

► Growing burden of atherosclerotic diseaseGrowing burden of atherosclerotic disease► Known and unknown risk factorsKnown and unknown risk factors► Stess test has limited positive predictive value Stess test has limited positive predictive value

specially for one vessel diseasespecially for one vessel disease► MSCT is a cross-sectional imaging techniqueMSCT is a cross-sectional imaging technique

It shows the contrast-enhanced vessel lumen (like cath)It shows the contrast-enhanced vessel lumen (like cath) It also has the potential to visualize the vessel wall and non-It also has the potential to visualize the vessel wall and non-

obstructive soft or calcified coronary atherosclerotic plaqueobstructive soft or calcified coronary atherosclerotic plaque ► the only clinically available non-invasive study with the only clinically available non-invasive study with

this capability.this capability.► Do it like mammography for cancer screening?Do it like mammography for cancer screening?

MSCT as screning test?MSCT as screning test?ConsCons

► Come back to the oculo-stenotic reflex?Come back to the oculo-stenotic reflex?► Does CT add to the information obtained by Does CT add to the information obtained by

risk scores based on traditional risk factors?risk scores based on traditional risk factors?► Could we identify stable plaques, which will Could we identify stable plaques, which will

stay stable for years, from vulnerable stay stable for years, from vulnerable plaques prone to rupture and MI?plaques prone to rupture and MI?

► CT detects disease, but does it make CT detects disease, but does it make difference in prognosis?difference in prognosis?

► Cost and reimbursment issuesCost and reimbursment issues

Best use of MSCTBest use of MSCT► Patients who have equivocal stress-test results, Patients who have equivocal stress-test results,

such as a result that is uncertain or suspected to such as a result that is uncertain or suspected to be false positive or false negative; then the CT is be false positive or false negative; then the CT is a good test to confirm or exclude coronary a good test to confirm or exclude coronary disease disease

► Its high negative predictive value suggests it Its high negative predictive value suggests it could select patients who should not be referred could select patients who should not be referred to conventional angiography, thus avoiding to conventional angiography, thus avoiding unnecessary coronary angiograms.unnecessary coronary angiograms.

► CT as a first test should be used only in a selected CT as a first test should be used only in a selected population, perhaps in patients of younger age in population, perhaps in patients of younger age in whom the likelihood of having a lot of calcium in whom the likelihood of having a lot of calcium in the coronaries is low. . . . the coronaries is low. . . .

MSCT in highly suspected CAD?MSCT in highly suspected CAD?

►Typical chest painTypical chest pain►Positive test for ischemia (Stress test, Positive test for ischemia (Stress test,

nuclear imaging)nuclear imaging)►Little place for MSCTLittle place for MSCT►Go directly to coronary angiography, Go directly to coronary angiography,

you can do PTCA in the same timeyou can do PTCA in the same time

MSCT in known CADMSCT in known CAD

►Follow-up of Follow-up of CABG ?CABG ?

►Follow-up of stent Follow-up of stent placement ?placement ?

LimitationsLimitations

►Need to have a relatively slow, regular Need to have a relatively slow, regular rythmrythm

►Check renal function before injecting Check renal function before injecting IodineIodine

►Problem raised by calcificationsProblem raised by calcifications►There is still some difficulty identifying There is still some difficulty identifying

stenosis in peripheral segmentsstenosis in peripheral segments► Issues raised by high level of radiationIssues raised by high level of radiation

Effective radiation dose from Effective radiation dose from various coronary diagnostic studiesvarious coronary diagnostic studies

►Cardiac Cath = 5-6 mSv.Cardiac Cath = 5-6 mSv.►MSCT = 12-14 mSv.MSCT = 12-14 mSv.►Calcium scoring scan= 2.6 mSvCalcium scoring scan= 2.6 mSv►SPECT Thallium = 18 mSv.SPECT Thallium = 18 mSv.►SPECT Sestamibi = 12.2 mSv.SPECT Sestamibi = 12.2 mSv.►Normal environment radiation is 3.5 Normal environment radiation is 3.5

mSv/y.mSv/y.Persinakis, health physics 2002. Persinakis, health physics 2002.

Risk of fatal cancerRisk of fatal cancer

► The International Commission on Radiological The International Commission on Radiological Protection (ICRP) has estimated that the additional Protection (ICRP) has estimated that the additional lifetime risk of fatal cancer is approximately 1 in lifetime risk of fatal cancer is approximately 1 in 20,000 per mSv for the whole population 20,000 per mSv for the whole population

► Based on available estimates, a coronary CT Based on available estimates, a coronary CT angiogram with an effective dose of 14.7 mSv has a angiogram with an effective dose of 14.7 mSv has a risk of inducing a fatal cancer of 1 in 1,400. risk of inducing a fatal cancer of 1 in 1,400.

► Conventional coronary angiography (5.6 mSv) has a Conventional coronary angiography (5.6 mSv) has a risk of 1 in 3,600risk of 1 in 3,600

► and a calcium-scoring scan (2.6 mSv) a risk of 1 in and a calcium-scoring scan (2.6 mSv) a risk of 1 in 7,700 7,700

► We never thought about this risk before !!We never thought about this risk before !!

ACCF/ACR/SCCT/SCMR/ASNC/NASCI/SCAI/SIR ACCF/ACR/SCCT/SCMR/ASNC/NASCI/SCAI/SIR Appropriateness Criteria for Cardiac Computed Appropriateness Criteria for Cardiac Computed Tomography and Cardiac Magnetic Resonance Tomography and Cardiac Magnetic Resonance

ImagingImaging

► A Report of the American College of Cardiology Foundation Quality A Report of the American College of Cardiology Foundation Quality Strategic Directions Committee Appropriateness Criteria Working Strategic Directions Committee Appropriateness Criteria Working Group, American College of Radiology, Society of Cardiovascular Group, American College of Radiology, Society of Cardiovascular Computed Tomography, Society for Cardiovascular Magnetic Computed Tomography, Society for Cardiovascular Magnetic Resonance, American Society of Nuclear Cardiology, North American Resonance, American Society of Nuclear Cardiology, North American Society for Cardiac Imaging, Society for Cardiovascular Angiography Society for Cardiac Imaging, Society for Cardiovascular Angiography and Interventions, and Society of Interventional Radiologyand Interventions, and Society of Interventional Radiology

Hendel RC, Patel MR, Kramer CM, Poon M.Hendel RC, Patel MR, Kramer CM, Poon M.

J Am Coll Cardiol. 2006;48:1475-1497.J Am Coll Cardiol. 2006;48:1475-1497.

Report SummaryReport Summary Cardiac Computed Tomography Cardiac Computed Tomography

(CCT)(CCT) ► 1. CCT is not appropriate for initial screening of the 1. CCT is not appropriate for initial screening of the

general population or as an initial tool in evaluation general population or as an initial tool in evaluation of symptomatic individuals suspected of having of symptomatic individuals suspected of having coronary artery disease (CAD). coronary artery disease (CAD).

► 2. CCT is considered appropriate for evaluation of 2. CCT is considered appropriate for evaluation of CAD in patients with prior inconclusive stress test CAD in patients with prior inconclusive stress test results. results.

► 3. CCT is considered highly appropriate for detection 3. CCT is considered highly appropriate for detection and evaluation of suspected coronary artery and evaluation of suspected coronary artery anomalies. anomalies.

► 4. CCT is not appropriate for evaluation of bypass 4. CCT is not appropriate for evaluation of bypass grafts and stents in asymptomatic patientsgrafts and stents in asymptomatic patients

► 5. CCT is considered highly appropriate for 5. CCT is considered highly appropriate for evaluation of complex cardiac anatomy, especially as evaluation of complex cardiac anatomy, especially as related to congenital heart disease. related to congenital heart disease.

Report SummaryReport Summary

► 6. CCT is considered highly appropriate for 6. CCT is considered highly appropriate for evaluation of cardiac masses such as tumor or evaluation of cardiac masses such as tumor or thrombus, when not ideally evaluated with thrombus, when not ideally evaluated with echocardiographic techniques. echocardiographic techniques.

► 7. 7. CCT is CCT is considered appropriate for evaluation of considered appropriate for evaluation of pericardial disease such as constriction, cyst, or pericardial disease such as constriction, cyst, or mass when information was not available from mass when information was not available from echocardiographyechocardiography

► 8. CCT with angiography was considered highly 8. CCT with angiography was considered highly appropriate for evaluation of suspected appropriate for evaluation of suspected pulmonary embolus. pulmonary embolus.

► 9. CCT is considered of uncertain appropriateness 9. CCT is considered of uncertain appropriateness for risk stratification prior to non-cardiac surgery.for risk stratification prior to non-cardiac surgery.

In conclusionIn conclusion

►MSCT will undoubtedly modify our way MSCT will undoubtedly modify our way of thinkingof thinking

► Its place in the screening of Its place in the screening of asymptomatic persons with multiple asymptomatic persons with multiple risk factors for CAD needs to be definedrisk factors for CAD needs to be defined

►Who will resist the temptation of having Who will resist the temptation of having a look to his coronary arteries by a non a look to his coronary arteries by a non invasive technique and without moving invasive technique and without moving one leg ?one leg ?