1. The use of Cardiac CT and MRI in Clinical Practice
Matthew W. Martinez, MD
Assistant Professor of Medicine
LVPG - Lehigh Valley Heart Specialists
Lehigh Valley Health Network
Oct. 3, 2009

2. Relevant Financial Relationship(s)
DISCLOSURE
Relevant Financial Relationship(s)
None
Off Label Usage

3. Learning Objectives Review basics of cardiac MRI and CTA
Review utility of cardiac CT and MRI in clinical practice
Clinical cases

4. Noninvasive Tests for the Diagnosis of Coronary Artery Disease
TMET
SPECT
Echo
PET CT
MRI

5. Black-Blood (Spin-Echo)
Cardiac MRI
Black-Blood (Spin-Echo)
Delayed Enhancement
White-Blood
SSFP
Still Images
Morphology
Edema
Cine Imaging
Morphology and function
Still Images
Delayed Enhancement

6. SSFP = 2D echo

7. Delayed Enhancement-MRI
Images obtained minutes post-contrast (Gd)
Normal myocardium – Black *
Necrosis/scarring/inflammation – Hyperenhanced
Image in Press – Nature of Clinical Practice

8. Infarct size by MRI Delayed Enhancement
Abundance of validation data in animal models
Dog with near-transmural infarct
Visible on SPECT and DE-MRI
3 dogs with subendocardial infarcts
Visible on DE-MRI only CP

9. Hyperenhancement Patterns Subendocardial infarct
Ischemic
Nonischemic
Subendocardial infarct
Mid-wall HE
Epicardial HE
Transmural infarct
Idiopathic dilated cardiomyopathy
Myocarditis
Hypertrophic cardiomyopathy
Right ventricular pressure overload
Sarcoidosis
Myocarditis
Anderson–Fabry disease
Shah DJ et al: Magnetic resonance of myocardial viability

10. RV Function
Mass
Cardiomyopathies

11. Tissue characterization
Cardiac MRI
Functional
Analysis
Tissue characterization
RV ESV
RV EDV
RV Stroke volume
RVEF
LVEF
LV mass
Wall Motion
LV ESV
LV EDV
LV stroke volume
Infarct identification
Infarct size
Viability

12. Unstable Hemodynamics
Evaluation of Chest Pain
Imaging
Prognosis
Viability
Function
Infarct size
ACS
Unstable Hemodynamics
and Complications CP
Echocardiography has versatile modalities for integrated cardiac function assessment. LV size, volume, and ejection fraction are obtained by 2-D, now with real time 3-D with a better reliability. Intracardiac hemodynamics including stroke volume and regrugitation as well as valvular hemodynamics can be quantitated by Doppler and CFI. Contrast echocardiography improves endocardial border definition and myocardial perfusion, and tissue/strain imaging provides
Cardiac functional information at the cellular level. Timing intervals which are very closely regulated by cardiac function are better measured by these new technologies.

13. Tissue characterization
Cardiac MRI
Functional
Analysis
Tissue characterization
RV ESV
RV EDV
RV Stroke volume
RVEF
LVEF
LV mass
Wall Motion
LV ESV
LV EDV
LV stroke volume
Infarct identification
Infarct size
Viability
Prognosis

14. Case 1 57-year-old woman Troponin – 0.56, 0.5 (3h), 0.36 (6h)
Sudden onset of achy, continuous, substernal, 8/10 chest pain
Radiating to back
Pain came on at rest
Cardiac Risk Factors
Never Smoker
Hyperlipidemia (untreated)
Sedentery Lifestyle
Troponin – 0.56, 0.5 (3h), 0.36 (6h)

15. Echocardiogram

16. Cardiac Catheterization

17. Cardiac Catheterization

19. Cardiac MRI
Left ventricular function is well maintained with an EF of 63%.
Regional wall motion abnormalities are seen with hypokinesis of the inferior and inferoseptal wall at the midventricular level. At the apex, there is akinesis of the inferior, septal, and lateral walls.
Perfusion defects are seen within the inferior and inferoseptal regions at mid ventricular level and apex.
Delayed enhancement involving the inferior wall and inferoseptal wall is seen at midventricular level and apex. This enhancement is transmural, consistent with non-viable myocardium, and there are areas of microvascular obstruction present.
LV End Diastolic Volume: mL 70 mL/m²
LV End Systolic Volume: mL 25 mL/m²
LV Stroke Volume: mL 44 mL/m²
LV Ejection Fraction: % 57-81
LV End Diastolic Mass: g 40 g/m²
LV End Diastolic Dimension: mm 36-54
RV Ejection Fraction: % 53-73

20. Cardiac MRI
Left ventricular function is well maintained with an EF of 63%.
Regional wall motion abnormalities are seen with hypokinesis of the inferior and inferoseptal wall at the midventricular level. At the apex, there is akinesis of the inferior, septal, and lateral walls.
Perfusion defects are seen within the inferior and inferoseptal regions at mid ventricular level and apex.
Delayed enhancement involving the inferior wall and inferoseptal wall is seen at midventricular level and apex. This enhancement is transmural, consistent with non-viable myocardium, and there are areas of microvascular obstruction present.
LV End Diastolic Volume: mL 70 mL/m²
LV End Systolic Volume: mL 25 mL/m²
LV Stroke Volume: mL 44 mL/m²
LV Ejection Fraction: % 57-81
LV End Diastolic Mass: g 40 g/m²
LV End Diastolic Dimension: mm 36-54
RV Ejection Fraction: % 53-73
Acute MI

21. Importance of unrecognized Myocardial scar
Aim: Assess the prognostic significance of unrecognized myocardial scar by MRI in patients without a history of MI
195 patients without known prior MI
1) Pts with unknown status of CAD referred for assessment of LV fxn, scar
2) Pts with angiographic CAD referred for prediction of segmental wall motion after revascularization (22)
16 month follow-up
Circulation, 2006

22. Case Presentation 2 History of Present Illness Past Medical History
46 year old man presents to ED, 6:30 AM with 10/10 chest pain
Began 4:30 AM - Radiated to left arm
No SOB, no n/v
Feeling ill with episodic CP over past 2 weeks
Past Medical History
Hyperlipidemia at health fair
Medications
none
Social History
30 pack year history, currently smokes 1 pack/week

23. Initial ECG

24. Angiography Results Troponin Elevation:
Baseline hr hr 0.49

25. Cardiac MRI

26. Delayed Enhancement
Myocarditis

27. Etiologies of Elevations of Cardiac Troponins
Plaque rupture mediated necrosis
STEMI
nSTEMI
Alterations in coronary vasomotor tone
Coronary spasm
Subarachnoid hemorrhage
Intracranial hemorrhage
Apical Ballooning Syndrome
Transplant vasculopathy
Sub-endocardial myocyte necrosis
CHF
Hypertensive crisis
Acute pulmonary embolism
Tachycardia-mediated – CHF, Pressure overload
Volume-Pressure overload
(renal failure, CHF, fluid resuscitation)
Anemia
Hypotension
Aortic Stenosis and / or Regurgitation
Hypertrophic Cardiomyopathy
Amyloid heart disease

28. Problem Solving Tool
Troponin is extremely sensitive for detecting myocardial cell necrosis
9-14% of patients who present with ACS will have normal or non-significant disease on coronary angiography
This cohort of patients have been shown to have a poorer prognosis; potentially from clinical uncertainty (TACTICS-TIMI-18)

29. Nice paper which demonstrated that in those patients with normal coronary arteries and elevated troponins other diagnoses were present….Myocarditis in 50%, Infarct in 11% and then no abnormalities in another 35%. This 35% have only modest elevations in troponin levels

30. Development of CT MDCT 4-slice 1998 MDCT 16-slice 2002
DSCT 128-slice 2009
MDCT 8-slice 2001
MDCT 64-slice 2004
DSCT 64-slice 2006
2000
2010
2015

32. CT Scanning
Minimally
Invasive
Angiography

33. Nuclear Cardiac Imaging Diagnostic Accuracy
Imaging Modality
# of Studies
Patients
Sen. (%)
Spec. (%)
Accuracy
SPECT 99mTc*
> 45
~7,000
83-86
73-75
83-86%
CTA*
>20
~2,000
83-94
77-92
89-92
CTA – hig-interm risk pts; 62% CAD; at least 1 vessel > 50%; NPV 97% per segment
SPECT – not corrected for referral bias; corrected-all values improved; Normalcy rate – 91%
Lack of correlation between stenosis % on QCA and CTA-64 (r=0.54)
“GOLD” Standard - Angiography

34. MDCT in Clinical Practice A Clinician’s Viewpoint
Gold Standard
Anomalous coronary vessels
Coronary fistula, aneurysms
Coronary Disease
Great for ruling out CAD
OK (but not great) for disease severity

35. What are you looking for?
Atherosclerosis
Fixed
obstruction
Ischemic
burden

36. Intermediate Probability
Patient Population
High Probability
Intermediate Probability
Low Probability
“Definite” signs of CAD:
Typical chest pain
ECG changes & cardiac enzyme elevation
Personal history of CAD

37. Intermediate Probability
Patient Population
High Probability
Intermediate Probability
Low Probability
“Indeterminate” signs of CAD:
Atypical chest pain
Discordant symptoms & stress test results
High risk factors & negative stress test
Low risk factors & positive stress test
Patient reluctant to have a cath

38. Intermediate Probability
Patient Population
High Probability
Intermediate Probability
Low Probability
CTA

39. Intermediate Probability
Patient Population
High Probability
Intermediate Probability
Low Probability
“Doubtful” signs of CAD:
“Worried well”

40. Intermediate Probability
Patient Population
High Probability
Intermediate Probability
Low Probability
? CTA ?

41. Intermediate Probability
Patient Population
High Probability
Intermediate Probability
Low Probability
CTA
? CTA ?

42. History 49yr female previously healthy
6+ months of dyspnea on exertion
No personal history of hyperlipidemia, HTN, CAD, smoking, and family history
Currently on no cardiac medications
BMI = 36.

43. History Exercise Time: 7.3 minutes
Test was stopped due to dyspnea and leg fatigue
32,736 (SBP x HR)
Stress Echo with an area of anterior ischemia was noted from mid to the base
ECG was negative

44. Appropriateness for CT

49. References supporting the use of coronary CTA following equivocal exercise sestamibi
Schuijf, J., et. al, “Relationship between Noninvasive Coronary Angiography with Multi-slice Computed Tomography and Myocardial Perfusion Imaging” Journal of the American College of Cardiology; December 19, 2006.
Rubinstein, R., et. al, “Usefulness of 64-slice multidetector computed tomography in diagnostic triage of patients with chest pain and negative or nondiagnostic exercise stress test result” American Journal of Cardiology 2007; 99:
Danciu, S., et. al, “Usefulness of multislice computed tomography coronary angiography to identify patients with abnormal myocardial perfusion stress in whom diagnostic catheterization could be avoided” American Journal of Cardiology 2007; 100:
Dewey, M., et. al, “Head-to-head comparison of multislice computed tomography and exercise electrocardiography for diagnosis of coronary artery disease” European Heart Journal 2007; 28:

50. Case 2 –chest pain 55 y/o woman Substernal chest discomfort 2 mos
Emotion and sometimes exertion
Today 10 min chest and back
pain at rest  ED
Postmenopausal
Prior smoker >15 yrs ago
No FH
No meds
Mild HTN

51. Exam: no murmur
BP 142/88
Troponin: <.01
Creat: 0.8

52. Acute chest pain What do you want to know?
Risk of
acute
event
High  Angio
Probability
CAD
Low
Intermediate
Low/inter

53. What to Do?
Sestamibi
Stress Echo
Coronary CTA

54. CTA vs Standard of Care in Chest Pain
Low risk
197 pts
MSCT
Standard care
Normal
Nondiag
Severe
Stress Nucs
Stress Nucs
Angio
HOME
HOME
Goldstein JACC :863-71

55. Length of stay: lowered by 43% 12.5 hrs vs 22.1 hrs
CTA – 67% normal and discharged
9% severe CAD  cath
24% needed further eval
Length of stay: lowered by 43%
12.5 hrs vs 22.1 hrs
Cost of care: lowered by 15%
$1586 vs $1872
Goldstein JACC :863-71

57. Conclusions Cardiac MRI EF, ESV, EDV, RV function, infarct size
ICM vs DCM
ACS
Cardiac CT
Excellent for exclusion of CAD in low to intermediate risk
ED patients, “equivocal stress test”

58. THANK YOU!