Background and aims:
Intraplaque haemorrhage (IPH) contributes to enlargement of the lipidcore
and plaque progression, leading to plaque destabilization. The
mechanisms that contribute to IPH development are not completely
understood. We hypothesise that development of IPH is affected by
biomechanical and hemodynamic variables and that fissuring or rupture of
the fibrous cap can contribute to IPH. The biomechanical load and wall
shear stress are highest in the proximal region of the plaque. We aim to
study non-invasively a possible difference in volume of IPH in the
proximal region of the plaque.
Methods:
88 symptomatic stroke patients with carotid stenosis included in the
Plaque At RISK (PARISK) study demonstrated ipsilateral carotid IPH on
multi-sequence MR images. Inner and outer vessel wall contours and IPH
area (hyperintense signal on MPRAGE/3D-T1-weighted fat suppressed spoiled
gradient echo images in the bulk of the plaque) were delineated on the MR
images by trained observers. IPH area was calculated with respect to the
total vessel wall area. Fibrous cap status was scored by comparing preand
post-contrast black blood TSE images. Differences in mean IPH
percentages between proximal and distal regions were calculated using a
paired samples t-test, while a McNemar test was used to reveal
differences in proportions of a thin and/or ruptured fibrous cap.
Results:
We found significantly larger areas of IPH in the proximal part of the
plaque at 2, 4, and 6 mm from the position of maximal luminal narrowing,
respectively: 14.4% vs. 9.6% (p=0.04), 14.7% vs. 5.4% (p < 0.001), and
11.1% vs. 2.2% (p=0.001). Additionally, we found an increased proximal
prevalence of a thin and/or ruptured fibrous cap on MRI at 2, 4, 6, and 8
mm from the MRI slice with maximal luminal narrowing, respectively; 33.7%
vs. 18.1%, p=0.007; 36.1% vs. 7.2%, p < 0.001; 33.7% vs. 2.4%, p=0.001;
30.1% vs. 3.6%, p=0.022.
Conclusion:
We demonstrated that IPH is more prevalent on the proximal side of the
plaque compared to the distal side. This may indicate that wall stress
and wall shear stress play an important role in the development of IPH.

03 - UPSTREAM REGION OF CAROTID PLAQUE SHOWS MORE INTRAPLAQUE HEMORRHAGE IN STROKE PATIENTS: THE PLAQUE AT RISK (PARISK) STUDY