Numerical simulations of carotid MRI quantify the accuracy in measuring atherosclerotic plaque components in vivo

Abstract

Current clinical MRI can quantify carotid plaques but shows limitations for thin FC thickness quantification. These limitations could influence the reliability of carotid MRI for assessing plaque rupture risk associated with FC thickness. Overall, MRI simulations provide a feasible methodology for assessing segmentation and quantification accuracy, as well as for improving scan protocol design.

The Influence of Inaccuracies in Carotid MRI Segmentation on Atherosclerotic Plaque Stress Computations

“…The current clinically achievable resolution of in vivo MRI is a limiting factor in measuring submillimeter features such as thin FCs, which are especially present in vulnerable plaques [11,15,19,23,24]. This raises concern, because the sensitivity of biomechanical FEA plaque models to FC thickness is very high [13,14,25,26].…”

Carotid Plaque Morphological Classification Compared With Biomechanical Cap Stress

“…These 32 cross sections were used in our previous studies. 15,16 A numeric MRI simulation consists of modeling MRI physics by solving the Bloch equations for a provided pulse sequence and ground truth computer sample model. The Jülich Extensible MRI Simulator was used for simulations.…”

“…17 A clinically applied, 2D, T1-weighted, turbo spin-echo, gadolinium contrast enhanced, black-blood sequence on a 3.0T full-body system was simulated. 15 The repetition/echo times were 800 ms/10 ms respectively. A reduced field-of-view of 37×37 mm 2 was simulated with a matrix size of 60×60.…”

“…An MRI-based stress computation resulted in a severely underestimated and imprecise peak cap stress because of overestimation of cap thickness, in particular for plaques with caps <0.62 mm. 15,16 The results of the comparison between the MRI-based peak cap stress and the histological classification of the underlying ground truth plaque are shown in Figure 4. In the high stress group (highest 25%), there was a large variation in the classification of the underlying plaque cross sections and large differences between the readers.…”

“…8 However, recent MRI simulation studies addressed limitations of carotid MRI about the spatial resolution for thickness measurements of thin fibrous caps. 15 This also has consequences for the reliability of stress computations of thin-cap, high-stress plaques. 16 Numeric computer simulations of MRI can be used as an effective means to investigate in vivo MRI segmentation accuracy.…”