The role of Magnetic Resonance Imaging in the diagnosis of viability & Coronary Artery Disease

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1 The role of Magnetic Resonance Imaging in the diagnosis of viability & Coronary Artery Disease G.P. Spanos, MSc, Phd Head of CardioVascular Imaging Tomographia Diagnostic Center

2 Cardiovascular magnetic resonance (CMR) imaging has recently emerged as a new noninvasive imaging modality.

3 MR Imaging has many advantages: not interventional no radiation (thallium >1500 Chest X-Rays) high spatial resolution imaging at any plane contrast media non-nephrotoxic

4 MR and Coronaries

5 Multi-center study of 109 patients with known CAD has shown: 636 from 759 prox and mid part (7 parts) of coronaries arteries could be evaluated with CMR (84%) LCA LAD LCx RCA Any coronary artery Left main/ triple vessel disease Sensitivity 87% 88% 83% 93% 93% 100% Specificity 90% 82% 70% 72% 42% 85% Accuracy 89% 65% 67% 80% 72% 87% Negative Predictive Value 98% 86% 86% 94% 81% 100% Kim WY, et al. N Engl J Med 2001;345:1863-9

6 MR and DSA of coronaries Kim WY, et al. N Engl J Med 2001;345:1863-9

7 Indications for MR scan of coronaries 1.Anomalous origins of coronary arteries 2.Kawasaki disease

8 Anomalous origins of coronary arteries Malignant aberrant right coronary artery Danias P, et al. Coronary Artery Disease 2001, 12:

9 MR and Infarction

10 Mechanism of myocardial Delayed contrast enhancement Late gad Normal myocardium Acute damage Scar Intact cell membrane Ruptured membrane Collagen matrix Vohringer M, et al, Herz 2007;32:129-37

11 Mechanism of Late Gad Normal myocardium Acute damage Scar Intact cell membrane Ruptured membrane Collagen matrix Vohringer M, et al, Herz 2007;32: Acute damage: acute myocarditis, acute infarcts Interstitial expansion: scar, fibrosis, myocardial disarray, deposition of amyloid distinct hyperenhancement patterns occur in different diseases

12 Delayed contrast enhancement (Late Gad) Technique 8 weeks after infarction Kim et al. Circulation 1999;100:

13 Hyperenhancement patterns that one may encounter in clinical practice Copyright restrictions may apply. Mahrholdt, H. et al. Eur Heart J : ; doi: /eurheartj/ehi258

14 Late Gad technique and MI TTC MRI Most Accurate at infarct size (40-fold higher spatial resolution than SPECT) Most Accurate at depiction of coexisting viable/non-viable myocardium Most Accurate at differenciation between transmural/nontransmural infarction

15 Late gad study of 556 patients with acute or chronic infarction with the following results: 99% sensitivity at detecting acute infarction 94% sensitivity at detecting chronic infarction Late gad valuable at symptomatic patients with no other findings (enzymes, ECG) Kim R et al, Circulation 2008

16 109 diabetics pts without clinical evidence of prior MI and 78 diabetics pts with MI underwent CMR + follow up 16 months 28% LGE >3-fold hazards increase for MACE and for death The presence of LGE by CMR was the strongest multivariable predictor of MACE and cardiac mortality compared with common clinical, ECG, and LV functional variables; Cardiac event similar with those with known MI Kwong et al., Circulation 2006

17 CMR late gad and SPECT studies has been conducted for detection of infarction at 91 patients and 15 dogs. At dogs: comparison with histological findings At dogs 100% sensitivity for CMR and SPECT at detection of transmural infarction 92% and 28% sensitivity respectively for CMR and SPECT at detection of subendocardial infarction (ischemai begins in the subendocardium as it has the highest metabolic demands) At patients SPECT detected only 47% of subendocardial infarctions depicted by CMR So, 13% of patients with subendocardial infarction depicted by CMR did not have indication of infarction at SPECT Wagner A et al. Lancet 2003 Feb 1;361(9355)

18 Kuhl HP, Beek AM, van der Weerdt AP, et al: Myocardial viability in chronic ischemic heart disease: comparison of contrast-enhanced magnetic resonance imaging with (18)F-fluorodeoxyglucose positron emission tomography. J Am Coll Cardiol 2003;41: Klein C, Nekolla SG, Bengel FM, et al. Assessment of myocardial viability with contrast-enhanced magnetic resonance imaging: comparison with positron emission tomography. Circulation 2002;105: %-96% sensitivity at detecting abnormal metabolism at PET 55% of subendocardial infarcts detected by CMR were normal at PET

19 Subendocardial MI: CMR-SPECT West A et al. Curr Prob Card, April 2010

20 Studies have shown that any increase at thickness of infarction diminishes the possibility of improvement, so: The infarct size measured by CMR predicts improvement in contractile function

21 Predictive value of late gad in 50 patients with dysfunctional LV, DE-CMR performed before and after by-pass or stenting: Kim RJ, et al. N Engl J Med 2000 Nov 16;343(20) 73% PPV for segments with akinesia, dyskinesia and DE-CMR 0-50% 0% PPV for segments with severe hypokinesia, akinesia or dyskinesia and DE-CMR >75%

22 Value of delayed-enhancement cardiovascular magnetic resonance imaging in predicting myocardial viability after surgical revascularization. Selvanayagam JB, Kardos A, Francis JM, Wiesmann F, Petersen SE, Taggart DP, Neubauer S. Circulation Sep 21;110(12): pts Delayed contrast-enhanced magnetic resonance imaging for the prediction of regional functional improvement after acute myocardial infarction. Beek AM, Kuhl HP, Bondarenko O, Twisk JW, Hofman MB, van Dockum WG, Visser CA, van Rossum AC. J Am Coll Cardiol Sep 3;42(5): Late gadolinium-enhanced magnetic resonance imaging in acute and chronic myocardial infarction. Improved prediction of regional myocardial contraction in the chronic state by measuring thickness of nonenhanced myocardium. Ichikawa Y, Sakuma H, Suzawa N, Kitagawa K, Makino K, Hirano T, Takeda K. J Am Coll Cardiol Sep 3;42(5):

23 MR and Infarction MR can detect, study, quantify and with high accuracy other findings with high prognostic value for patients with MI, like: LV dysfunction Thrombus Microvascular Obstruction (postinfarction complications, mortality and LV remodelling)

24 Posterior wall infarct Cine CMR Late gad Courtesy Royal Brompton Hospital

25 Late gad study

26 Ischaemic CM feloukidou4ch.avi Female, 63yrs, EF 46%, EDV 130(141)

27 Ischaemic CM feloukidou4ch.avi Male, 68yrs, EF 20%, EDV 295 (195)

28 Delayed Enhancement feloukidou4ch.avi Female, 49yrs, EF 70%, EDV 98(141)

29 CONCLUSION 1 Late gad technique is -the most sensitive technique to detect infarction and -the most accurate to measure infarct size Infarct size measured by CMR predicts improvement in contractile function MR can study and qualify other important factors for the prognosis of patients with MI (MO, LV dysfunction, thrombus)

30 CONCLUSION 2 Cardiac MR is very strong at DD of infarct and other causes of chest pain and positive troponin (myocarditis and non-ischemic cardiomyopathies)

31 MR and Ischemia

32 First Pass Perfusion Technique for studying the BLOOD FLOW at myocardium Stress and Rest imaging STRESS PERFUSION Courtesy Royal Brompton Hospital Stenosis delay at perfusion of contrast media > low concentration > lower signal intensity

33 First pass perfusion study and adenosine stress MR of 461 consecutive patients with suspicion or known CAD and patients were followed-up for >2yrs: The 2-year event-free survival was 99.2% After a normal nuclear scan, the major cardiac event rate is 1% per year during the 1 to 3 years after examination First pass perfusion has almost the same results (0,7% the 1 st and 2 nd year, 2,3% the 3 rd year) Prognostic stratification at least equivalent for MR and SPECT Jahnke C et al. Circulation. 2007

34 MR IMPACT STUDY In 18 centers in Europe and the United States, a total of 241 patients with known or suspected coronary artery disease (CAD) were recruited for MR-IMPACT. Patients were studied with perfusion CMR and within 4 weeks all patients were also studied with conventional x-ray coronary angiography and single photon emission computed tomography (SPECT) according to standard protocols (monitored by official authorities in Europe and US, i.e. EMEA and FDA, respectively) Thus, perfusion CMR detected 86% of patients with CAD, while only 74% were detected by SPECT. This high sensitivity of perfusion CMR went along with a specificity of 67%, which is important to keep the number of normal, and thus, unnecessary invasive x-ray coronary angiography examinations low. A similar specificity was achieved for SPECT with 57%. Schwitter J et al. Eur. Heart 2008

35 CE-MARC STUDY CE-MARC is the largest, prospective, real world evaluation of CMR funded by British Heart Foundation and published at Lancet, Dec 2011 Greenwood et al., Lancet Dec 2011

36 CE-MARC patients with suspected angina pectoris and at least one cardiovascular risk factor were scheduled for CMR, SPECT, and invasive x-ray coronary angiography. 39% had significant CHD Greenwood et al., Lancet Dec 2011

37 CE-MARC 3 MR SPECT Sensitivity 86,5% 66,5% Specificity 83,4% 82,6% PPV 77,2% 71,4% NPV 90,5% 79,1% Greenwood et al., Lancet Dec 2011

38 CE-MARC 4 Greenwood et al., Lancet Dec 2011

39 LAD stenosis stress rest Gebker R et al. Radiology. 2008

40 LAD stenosis stress rest Vogel-Claussen et al. JCMR 2009

41 LCx stenosis Chiu C.W. et al, Radiology 2003,

42 LAD stenosis Late Gad STRESS PERFUSION Plein S et al, Radiology 2005;235:

43 Global subendocardial ischemia stress rest Vogel-Claussen et al. JCMR 2009

44 Final conclusion A joint protocol of: Late gad First pass perfusion consists a: Study with the highest sensitivity at the detection of MIs Study with high prognostic value for functional improvement Viability/stress study at least equivalent with those used at daily clinical practice without radiation Highly reproducible study, no radiation, no intervention