1. 1 State of the art in Detection of Vulnerable Plaques Presented by : Shahryar Rahnamayan Ph.D. student Supervisors : Prof. H. R. Tizhoosh Prof. M. Salama 17 th March, 2003

2. 2 Our Gold Aim Stroke Prediction of Stroke

3. 3 Overview Some facts Stroke risk factors What cause stroke? What are Plaques? Plaques in carotid artery Some techniques for detection of Plaques Main factors for evaluation of techniques Conclusion

4. 4 63500 stroke Cases happened in 1999 ( Ontario ranked first (36.31%), Quebec ranked second (25.75 %) ) Canadian Institute for Health Information (CIHI). http://secure.cihi.ca/ Some facts In Canada :

5. 5 the third largest killer, after heart disease and cancer. About 700,000 People have strokes each year. About 500,000 of these are first attacks, and 200,000 are recurrent attacks. Stroke costs $30 to $40 billion per year. Texas Heart Institute, http://www.tmc.edu/ In US : S troke every 45 seconds !!!

6. 6 Stroke Risk Factors Risk Factors That Can Be Treated High Blood Pressure ( 1 in 4 American adults ) Heart disease ( at twice the risk ) Atherosclerosis ( hardening of the arteries) High red blood cell count ( can lead to blood clots ) Transient ischemic attacks (TIAs ) ( temporarily blocks an artery in the brain or neck)

7. 7 Stroke Risk Factors Risk Factors That Can't Be Changed Age ( after 55, double every ten years ) Gender ( for men 19% higher than women ) Race ( for African Americans- Afro-American - is twice ) Diabetes ( because of circulation problems, for women is greater) Prior stroke ( ten times !) Heredity

8. 8 Risk Factors That Can't Be Changed (Continued) Carotid artery disease ( fatty deposits found in the carotid artery ) Geographic location ( e.g. Stroke belt in US) Season and climate ( extreme temperature, e.g. June in Canada ) Socioeconomic factors ( lower income)

9. 9 Contributing Risk Factors Smoking ( doubles the risk ) Heavy alcohol use Physical inactivity ( 30-40 min. 3-4 time very week) Obesity ( BMI > 30 kg/msq.) Birth Control Pills ( if combined with other factors like smoking)

10. 10 Important point Many heart attack and stroke victims do not have symptoms in advanced.

11. 11 What is a stroke? A stroke is an injury to the brain that may also severely affect the body. A stroke happens when blood supply to part of the brain is cut off or when there is bleeding into or around the brain.

12. 12 Blood flow to the brain can be blocked in two ways: A clump of blood called a blood clot blocks an artery in the brain or neck. ( ~ 80% ) A weakened artery bursts in the brain. ( ~ 20%)

13. 13 What mainly causes blood cut off ?

14. 14 Short answer:Plaque

15. 15 What are Plaques ?

16. 16 “Plaque is a combination of cholesterol, other fatty materials, calcium, and blood components that stick to the artery wall lining. A hard shell or scar covers the plaque. Plaques have various sizes and shapes. Some plaques are unstable and can rupture or burst. When this happens, it causes blood clotting inside the artery. If a blood clot totally blocks the artery, it stops blood flow completely. This is what happens in most heart attacks and strokes.” Oral Chelation Therapy, http://www.oralchelation.ca/

17. 17 Stable and Unstable Plaque Heart Center Online, http://www.heartcenteronline.com

18. 18 Unstable Plaque = Vulnerable Plaques Heart Center Online, http://www.heartcenteronline.com

19. 19 Texas Heart Institute Heart Information Center, www.vp.org

20. 20 Plaques in Carotid artery cause stroke Heart Center Online, http://www.heartcenteronline.com

21. 21 MRI from Human Carotid Plaque Courtesy of Dr. Chun Yuan, University of Washington

22. 22 Relation between heart disease and obstruction in major artery Study findings showed : “Heart disease increased from 17% in people without obstruction in the carotid artery to 46% in those with obstruction of greater than 75% in at least one major artery.” Courtesy of Dr. Kallikazoros

23. 23 Some Techniques for detection of Plaques 1. Angioscopy 2. Intravascular Ultrasound (IVUS) 3. Intravascular Thermography 4. Intravascular Optical Coherence Tomography (OCT) 5. Intravascular Elastography 6. Intravascular MRI 7. Intravascular Nuclear Imaging 8. Intravascular Electrical Impedance Imaging 9. Intravascular (Photonic) Spectroscopy

24. 24 Continue … 10. Intravascular Tissue Doppler 11. Electron Beam Tomography (EBT) 12. Multi-slice Fast Spiral Computed Tomography

25. 25 Main factors for evaluation of techniques Safeness Invasive (part of the body is entered) or non-invasive Kind of information that gives Resolution Cost Acquisition time Localization Simplicity Easiness to apply

26. 26 Angioscopy Based on fiber-optic transmission of visible light - Adv. - anatomic - simple - Disadv. - just surface of plaque is visualized - limited spatial resolution - needs a proximal occluding balloon Courtesy of Uchida et al, Japan

27. 27IVUS Provides real-time, cross-sectional and high-resolution images with 3-D reconstruction capabilities - Adv. - Shows morphology of plaque - Differs between stable and unstable plaques - Disadv. - Doesn’t give information about inflammation - Low spatial resolution ( ~ 200 µm ) - Deeper plaque is not imaged Courtesy of Nissen, Yock and Fitzgerald

28. 28 Intravascular Thermography In two kinds : contact-based ( thermistor ) and non-contact based ( side-viewing infrared fiber- optic ) - Adv. - Simplicity in theory - Gives information about inflammation - Disadv. - Plaque temperature is affected by blood flow is measured - Needs a proximal occluding balloon to provide blood-free field - Not give information about eroded but non-inflamed plaques Courtesy of Volcano Therapeutics Inc. and http://www.tmc.edu

29. 29 Optical Coherence Tomography (OCT) Measures the intensity of reflected near-infrared light from tissue - Adv. - Very high resolution ( ~ 10 µm ) - Near video rate ( 8 frames/sec. ) - Catheters are small ( 0.014 inch ) - Disadv. - Long image acquisition time - Cost - Limited penetration - Lack of physiologic data Courtesy of Mark Brenzinski,James Fujimoto and Eric Swanson

30. 30 Intravascular Ultrasound Elastography Assesses the elasticity level of tissue based on cross-correlating the IVUS images acquired at different intra-arterial pressures applied to the arterial wall - Adv. - little cost added to IVUS - Provides novel information,Showing stiffness - Disadv. - Lack of chemical inferences Courtesy of de korte et al.

31. 31 Intravascular MRI An internal receiver coil is implanted at the tip of a catheter - Adv. - high resolution (~ 50 µm ) - lack of ionizing radiation - Disadv. - Long image acquisition time - High cost Courtesy of Ergin Atalar

32. 32 Electron Beam Tomography (EBT) Calcium imaging - Adv. - Quick and easy - Provides information about total burden of atherosclerosis - Disadv. -Can not distinguish unstable from stable Plaque - Not accurate Courtesy of Rumberger,Aard,Raggi, and others

33. 33 another classification for Plaques detection Techniques Morphology imaging ( IVUS, OCT,…) Activity imaging ( Thermography, Nuclear, …) Association for Eradication of Heart Attack - AEHA, http://www.vp.org/

34. 34 A good idea Using Combination of Morphological Functional Morphological and Functional imaging e.g. : IVUS + Doppler velocity measurements

35. 35 Conclusion Early detection of vulnerable Plaque is huge help for cardiovascular scientists to predict and prevent sudden death, most of mentioned techniques are in early research stage and call for scientist with any background to challenge.

36. 36 suggestion Doing joint project with great research centers like Vulnerable Plaque Research Department

37. 37 Special thanks to Association for Eradication of Heart Attack - AEHA, http://www.vp.org/

38. 38 Thank you for your time and attention Any Comments, Suggestions and Questions ?