MRI-Based Assessment of Neovasculariation in Carotid

Plaque – A Novel Risk Marker for Plaque Rupture

Michael Jerosch-Herold, PhDAssociate Professor of Radiology

Director of Physics for the Cardiac Imaging ProgramBrigham & Women’s Hospital

New 3.0 T Bilateral 8-Channel Carotid Array and Head-Holder for Reynold Carotid Study

Coil mounted on a frame with head-holder consists of two curved paddles

MGH DesignWiggins/Wald

Reference: Hinton-Yates et al., TMRI 2007

8- Coils = pair of four 4.8 cm loops

Head Holder

MRI Protocol for Dynamic Contrast Enhancement

• T1-weighted 3D fast gradient echo– TR/TE/flip angle: 4.3/2.3 ms/ 20°– 3 mm slices– In-plane resolution: 0.7 x 0.7 mm– Time per dynamic view: 14 s

• With new 8-element neck phased array the time per dynamic view is reduced to 10 s.

Post-Processing

Contrast-Enhancement in Carotid Wall

Kinetic Modeling(Kety-Schmidt Model)

Arterial Input Venous Outflow

Tissue Extraction (Ktrans)

vb

Model Parameters Determined by Optimization at Pixel Level• vb vascular volume• Ktrans First order blood-to-tissue transfer rate constant

Measured in vessel lumen

Ktrans Parametric Map

Ktr

ans*

1e3

[1/m

in]

24

20

16

12

8

4

Examp

Ktrans Parametric Map

Ktr

ans*

1e3

[1/s

]

24

20

16

12

8

4

T2 TSE: carotid plaque

Example of Test-Scan in Patient with 8-Channel Phased Array Coil