Quantitative magnetic resonance imaging analysis of neovasculature volume in carotid atherosclerotic plaque.
BACKGROUND
Neovasculature within atherosclerotic plaques is believed to be associated with infiltration of inflammatory cells and plaque destabilization. The aim of the present investigation was to determine whether the amount of neovasculature present in advanced carotid plaques can be noninvasively measured by dynamic, contrast-enhanced MRI.


RESULTS
A total of 20 consecutive patients scheduled for carotid endarterectomy were recruited to participate in an MRI study. Images were obtained at 15-second intervals, and a gadolinium contrast agent was injected coincident with the second of 10 images in the sequence. The resulting image intensity within the plaque was tracked over time, and a kinetic model was used to estimate the fractional blood volume. For validation, matched sections from subsequent endarterectomy were stained with ULEX and CD-31 antibody to highlight microvessels. Finally, all microvessels within the matched sections were identified, and their total area was computed as a fraction of the plaque area. Results were obtained from 16 participants, which showed fractional blood volumes ranging from 2% to 41%. These levels were significantly higher than the histological measurements of fractional vascular area. Nevertheless, the 2 measurements were highly correlated, with a correlation coefficient of 0.80 (P<0.001).


CONCLUSIONS
Dynamic contrast-enhanced MRI provides an indication of the extent of neovasculature within carotid atherosclerotic plaque. MRI therefore provides a means for prospectively studying the link between neovasculature and plaque vulnerability.
Kerwin
William
W
Department of Radiology, University of Washington, Seattle 98195, USA. bkerwin@u.washington.edu
Hooker
Andrew
A
Spilker
Mary
M
Vicini
Paolo
P
Ferguson
Marina
M
Hatsukami
Thomas
T
Yuan
Chun
C
D001810:Blood Volume; D002339:Carotid Arteries / Q000473:pathology / Q000601:surgery; D016893:Carotid Stenosis / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D016894:Endarterectomy, Carotid; D019786:Gadolinium DTPA / Q000493:pharmacokinetics; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008833:Microcirculation / Q000473:pathology; D008955:Models, Cardiovascular; D009389:Neovascularization, Pathologic / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D011237:Predictive Value of Tests; D011300:Preoperative Care; D014654:Vascular Patency
C064925:gadodiamide; D019786:Gadolinium DTPA