1. New Insights in Atherosclerosis Imaging 3D carotid plaque imaging 64 year old male patient with coronary artery disease and carotid plaques on ultrasound imaging underwent voluntary first step using CMR plaque imaging 3 D sequences M Romanens, 03.12.2001

2. 3D carotid plaque imaging: rationale and imaging parameters Rationale: atherosclerosis imaging with high resolution CMR (2000x400x400 microns) determination of reproducibility of measurements for plaque area and components extending CMR information with image fusion and isotropic computed tomography Imaging parameters: T1 3D black blood*ST 2 mmFOV 100 mmTE 9.4 msFlip 90° PD 3D black blood*ST 2 mmFOV 100 mmTE 9.4 ms**Flip 90° T2 3D black blood*ST 2 mmFOV 100 mmTE 40 ms**Flip 90° T2 3D black blood* with fat suppressionTE 40 ms**Flip 90° TOF 3DST 2 mmFOV 100 mmTE shortestFlip 25° * denotes cardiac triggering ** RR Interval two heart beats

3. 3D carotid plaque imaging: first results Interpretation: Ultrasound revealed a 3-4 mm thick long and smooth fibrous plaque in the left common carotid artery 3 cm below the flow devider. CMR confirms results of ultrasound with a homogenous fibrous plaque with only slight vessel lumen reduction (planimetry: 37%). Top row shows overview, lower row shows detail of left carotid artery always T1Proton Density T2T2 SPIR TOF Left CCA

4. 3D carotid plaque imaging: Conclusions These first preliminary results show that smooth plaque imaging using 3D CMR is possible no relevant flow artifacts occured swallowing did not degrade image quality plaque components may be characterized accuaretaly TOF imaging may be improved with increased flip angles Expectations for the future 3D black blood and 3D TOF imaging of plaque components of the carotid artery may be defined in a reproducible manner 3D imaging increases signal to noise ratio and may therefore increase image quality and reproducibility of measures of plaque components 3D imaging is still not warranted near the flow devider or when plaques should be imaged that create turbulent flow, because turbulances degrade image quality severely in most cases (possibly true for 2D also) 3D imaging may be difficult in heavily calcific plaques. Further research with emphasis on impact of calcifications on CMR plaque imaging is warranted using imaging fusion with isotropic contrast enhanced multislice computed tomography. Notification We are indepted to Philips Medical for their logistic help, especially Mr Wyss