Cardiac MR -Complimentary -Competitor -Conqueror?

Transcription

1 Cardiac MR -Complimentary -Competitor -Conqueror? Dr Girish Dwivedi MRCP (UK), PhD (UK), FASE Staff Cardiologist, Assistant Professor in Medicine University of Ottawa Heart Institute University of Ottawa, Canada

2 Today s talk Physics Indications and Examples Safety Questions

3 Physics Body lies on table encompassed by coils for static field (B o ), gradient fields (G z and G x shown), and radiofrequency field (RF or B 1 ). Nishimura DG. Principles of MRI. & Lawson Imaging 3-T facility, Siemens Verio

4 Which is likely to result in most harm or damage? A. Putting a patient with mechanical valves and sternal wires in MRI. B. Putting a patient with reveal device, stents or ASD occluder in MRI. C. Putting a patient with Pacemaker in MRI. D. Putting a patient with intracranial clip in MRI. E. Returning home late after finishing consults and forgetting your sigmificant others birthday.

5 Physics MRI: Mapping abundance & behavior of hydrogen nuclei in tissues. Tissues are largely water and fat many hydrogen atoms (humans are ~ 63% hydrogen!) Hydrogen nucleus comprised of a single proton Each proton can be viewed as a small magnetic field Bare H proton has a nuclear spin, and total angular momentum

6 My old boss

7 Difference between Iron and Steel Ferromagnetic Paramagnetic Diamagnetic

8 Processing

9 How does it work? T1 weighted Spin echo Gradient echo

10 So where is it useful, really? Left ventricular function Ischaemic Heart disease One stop Cardiomyopathy Dare you do it without CMR? Fascinomas Congenital heart disease And just about every other cardiac and great vessel disease.

11 So why bother? No dependence on acoustic windows can always get good quality images Can do things echo can t New perspectives on common diseases Can pick any plane Accurate Reproducible No radiation Image quality

12 It s not all good news Expensive Fixed Not real time Cardiac/respiratory artefacts Resolution

13 Portability

14 1. CMR LV function

15 Apex Base

16

17 LV-RV stroke volumes in normal hearts Longmore Lancet 1985;

18 Reduce number of subjects in trials Echo 230 CMR 28 Pennel, AHJ, 2002

19 2. Ischaemic heart disease

20 IHD Bulk of our work Myocardial Ischaemia Stress wall motion Stress perfusion Myocardial viability Complications of IHD Coronary angiography

21 Hibernating myocardium

22 Hibernating myocardium Hypokinetic myocardium which has the potential to improve in function Cellular integrity

23 Late enhancement Gd TTC MRI R Judd, Northwestern University, Chicago

24 Validation of Gadolinium Hyper enhancement in CMR

25 This is something unique: Imaging dead heart muscle as well as live heart muscle

26 Transmural Extent of Scar and Functional Recovery Kim R, ACC Sessions 2000

27 Gadolinium

28 Cine Late Gad

29 Case example 83 years old Little comorbidity Severely limited by SOB Severe 3 vessel disease Severely impaired LV function.

30 CMR- Pre CABG

31 CMR- Post CABG

32 Myocardial Perfusion

33 Rest Stress

34 Coronary artery imaging

35 Radiation Ca scoring X Ray angio CT angio Cardiac MR Echo Exercise testing

36 Anomalous RCA with Inter-arterial Course RCA Pulmonary trunk LCX NC R L LAD

37 Can it be done? Li D. Radiology 1996; 201:

38 3 Tesla coronary MR

39 But Not robust Not reproducible Resolution Technical issues Time Is it what we need?

40 3. Cardiomyopathy

41 HCM

42 Apical HCM

43 Case example

44 Right ventricular cardiomyopathy

45 ARVC

46 Iron cardiomyopathy

47 Before

48 And after

49 Congenital heart disease

50 Quadricuspid Aortic Valve

51 Complex ACHD

52 Next Images It s an attempt to image the first test baby by echo and shows a normal heart No, they represent Zebra fish embryo heart. Actually, a resident (this time medicine) is trying image an abnormal heart. None or all the above

53 Echo: Unclear Apical views

54 Congenital Heart Disease (real case) Abdominal and atrial situs solitus, AV/VA concordance. Malposition of the great arteries Tricuspid atresia Dextrocardia Juxtaposed right atrial appendages Acquired pulmonary atresia Aged 6 weeks right classical Blalock-Taussig shunt Aged 4 years left classical Blalock-Taussig shunt Aged 7 years modified Fontan operation (SVC to right pulmonary artery, right atrial appendage to left pulmonary artery)

55 Fontan operation Done in single ventricle circulation Congenital cardiac malformation in which one ventricle is dormant or biventricular repair is not possible

56 3D non-contrast enhanced MRI

57 Safety Mechanical valves, annuloplasty rings-ok ASD device, PFO, Duct closure etc-ok Stents: OK Pacemaker, ICD-XX Sternal wires, epicardial wires-ok Catheters if poly urethane or PVC OK LVAD and IABP-XXXX Guidelines for 1.5 T scanner

58 Gold standard 1. Ventricular volumes 2. Ventricular function 3. Complex congenital heart disease 4. Imaging of other structural abnormalities 5. Myocardial viability 6. (aortic disease)

59 On it s way Myocardial perfusion imaging Coronary artery imaging? Quantification of Myocardial function Scar Perfusion

60 The Future Single examination for CAD MR spectroscopy Real time imaging

61 Thank you