Improved characterization of atherosclerotic plaques by gadolinium contrast during intravascular magnetic resonance imaging of human arteries.
OBJECTIVE
To determine whether gadolinium-DTPA (Gd-DTPA) facilitates discrimination of fibrous, lipid or calcified constituents during intravascular magnetic resonance imaging (IVMRI) of human atherosclerotic arteries.


BACKGROUND
Atherosclerotic plaques that cause fatal thrombosis due to rupture have high content of lipid relative to fibrous tissue. We recently demonstrated that IVMRI identifies lipid, fibrous, and calcified components within atherosclerotic human arteries with favorable sensitivity and specificity. Gd-DTPA, a T1-shortening agent, selectively amplifies the signal from fibrous tissue on T1 weighted (T1w) surface MRI.


METHODS
A 0.030 in. diameter receiver coil coupled to a 1.5T MR scanner was positioned in iliac arteries of nine subjects with atherosclerosis. Previously validated multi-parametric analysis of T1w and moderate T2w images identified 137 fibrous, lipid and calcified regions of interest within 37 arterial segments. T1w imaging was repeated following 0.1 mmol/kg IV Gd-DTPA infusion.


RESULTS
Computer-derived mean gray value in fibrous regions increased by 34.2% with Gd-DTPA (95% CI 24.3-43.5%, p=0.0001) while lipid and calcified regions showed only a non-significant increase of 4.3% (95% CI -0.6 to 9.2%, p=0.0825) and 3.8% (95% CI -1.1 to 7.7%, p=0.103), respectively. The increase in mean gray value with Gd-DTPA was greater for fibrous than for lipid or calcified regions (p=0.0001).


CONCLUSIONS
Gd-DTPA selectively enhances signal intensity of fibrous constituents during IVMRI of human atherosclerotic arteries and thus identifies key tissue characteristics associated with plaque stability. These findings have important implications for the assessment of plaque-stabilizing therapies and ultimately for reducing cardiovascular events.
Larose
Eric
E
Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, United States.
Kinlay
Scott
S
Selwyn
Andrew P
AP
Yeghiazarians
Yerem
Y
Yucel
E Kent
EK
Kacher
Daniel F
DF
Libby
Peter
P
Ganz
Peter
P
D000368:Aged; D050197:Atherosclerosis / Q000175:diagnosis*; D003287:Contrast Media; D003324:Coronary Artery Disease / Q000175:diagnosis*; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007083:Iliac Artery / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged
D003287:Contrast Media; D019786:Gadolinium DTPA