Signal-to-noise ratio increase in carotid atheroma MRI: a comparison of 1.5 and 3 T

Abstract

Objectives: This study reports quantitative comparisons of signal-to-noise ratio (SNR) at 1.5 and 3 T from images of carotid atheroma obtained using a multicontrast, cardiacgated, blood-suppressed fast spin echo protocol. Methods: 18 subjects, with carotid atherosclerosis (.30% stenosis) confirmed on ultrasound, were imaged on both 1.5 and 3 T systems using phased-array coils with matched hardware specifications. T 1 weighted (T 1 W), T 2 weighted (T 2 W) and proton density-weighted (PDW) images were acquired with identical scan times. Multiple slices were prescribed to encompass both the carotid bifurcation and the plaque. Image quality was quantified using the SNR and contrast-to-noise ratio (CNR). A phantom experiment was also performed to validate the SNR method and confirm the size of the improvement in SNR. Comparisons of the SNR values from the vessel wall with muscle and plaque/ lumen CNR measurements were performed at a patient level. To account for the multiple comparisons a Bonferroni correction was applied. Results: One subject was excluded from the protocol owing to image quality and protocol failure. The mean improvement in SNR in plaque was 1.9, 2.1 and 2.1 in T 1 W, T 2 W and PDW images, respectively. All plaque SNR improvements were statistically significant at the p,0.05 level. The phantom experiment reported an improvement in SNR of 2.4 for PDW images. Conclusions: Significant gains in SNR can be obtained for carotid atheroma imaging at 3 T compared with 1.5 T. There was also a trend towards increased CNR. However, this was not significant after the application of the Bonferroni correction.

Atherosclerotic Carotid Plaque Composition: A 3T and 7T MRI‐Histology Correlation Study

“…[13][14][15] Most CPI has been performed at 1.5T, although a few recent studies have used 3T. Similar relative appearances on multi-contrast techniques [18][19][20][21] have been report at 1.5T and 3T.…”

Semiautomated analysis of carotid artery wall thickness in MRI

“…In this study only PDWI images were analyzed because these have the best signal-to-noise ratio (SNR). These data were demonstrated by Young et al (26), who found that in the 3T systems the PDWI also shows the best SNR in the carotid artery wall/ plaque. In another article by Biasiolli et al (27), it was found that the PDWI images have a reduced blur edge.…”

Guideline treatment results in regression of atherosclerosis in type 2 diabetes mellitus

“…However, the inferior field strength in a head-to-head comparison has proven to be equally utilizable for morphometric measurements, despite lower signal-to-noise ratios. 25,26 Our method for patient selection using ultrasonography to detect common CA stenosis may have yielded a heterogeneous group of patients. Since carotid ultrasound measurement of plaque only includes the interior quadrant of the CA, this technique may overestimate the actual stenosis rate as measured by MRI.…”