Original Research Assessment of the Carotid Artery by MRI at 3T: A Study on Reproducibility Reza Alizadeh Dehnavi, MD, 1 * Joost Doornbos, PhD, 2 Jouke T. Tamsma, MD, 1 Matthias Stuber, PhD, 3 Hein Putter, PhD, 4 Rob J. van der Geest, MS, 5 Hildo J. Lamb, MD, 2 and Albert de Roos, MD 2 Purpose: To examine the reproducibility of carotid artery dimension measurements using 3T MRI. Materials and Methods: Ten healthy volunteers under- went three scans on two occasions for assessment of total vessel wall area (TVWA), total luminal area (TLA), and min- imum (MinT) and maximum (MaxT) vessel wall thickness. A double inversion-recovery (IR) fast gradient-echo (FGRE) sequence was used on a commercial 3T system. During the first visit the subjects were scanned twice. The third scan was performed at least four days later. One observer traced all scans, and a second observer retraced the first scan series. Results: For TVWA an interclass correlation (ICC) of 0.994 was calculated with all three scans taken into account. The interobserver ICC was 0.984. The agreement between the scans for TLA showed an ICC of 0.982 with an interobserver ICC of 0.998. For MinT and MaxT an ICC of 0.843 and 0.935 were calculated, with interobserver ICCs of 0.860 and 0.726, respectively. Conclusion: With the use of a commercial 3T MR system, TVWA, TLA, and wall thickness measurements of the ca- rotid artery can be assessed with good reproducibility. Key Words: carotid artery; vessel wall area; luminal area; 3T MRI; reproducibility; fast gradient echo J. Magn. Reson. Imaging 2007;25:1035–1043. © 2007 Wiley-Liss, Inc. CARDIOVASCULAR DISEASE IS THE LEADING CAUSE of morbidity and mortality in the western world, and atherosclerosis is the primary underlying patho- physiological process. Atherosclerosis is regarded as a chronic inflammatory disease that can start at an early age (1) and progress throughout life, causing structural changes in the arterial wall (2). This process is modu- lated by known risk factors such as dyslipidemia, dia- betes, and hypertension, and can result in more prom- inent arterial wall structural changes in subjects who are at risk for developing cardiovascular disease (3). The relevance of arterial vascular structural changes for both clinical and research settings has been dem- onstrated in several studies (4 –9). The carotid intima media thickness (IMT) as mea- sured by high-resolution B-mode ultrasound imaging has been shown to correlate both with clinical cardio- vascular disease and the level of risk factors present (5– 8). Both the absolute IMT and its increase have been demonstrated to be predictive of future coronary events in subjects with prior coronary heart disease (9). The predictive power of the IMT has been shown to be inde- pendent of other risk factors (4 –9). Furthermore, the importance of tomographic assessments of the arterial wall has been illustrated in studies in which, after a pharmacological intervention, a reduction in either the event rate or the vessel wall area was observed dispro- portionately to or in the absence of luminal changes (10 –12). Accurate assessments of the arterial vascular structure and possible changes in that structure over time are therefore of great importance because they both reflect the current disease burden and are predic- tive of future events. Magnetic resonance imaging (MRI) has emerged in recent years as a promising noninvasive imaging modality for the serial assessment of athero- sclerosis (13–15). Its ability to quantify total plaque volume and disease burden has been demonstrated (16 –18). The accuracy of the technique for assessing the atherosclerotic plaques was validated in compari- son with histopathology in an ex vivo study (19). MRI has also been shown to be able to characterize plaque composition in vivo (20). The introduction of whole-body 3.0T field-strength magnets has created new opportunities to further de- velop MRI. Improved signal-to-noise ratio (SNR), con- 1 Vascular Medicine, Department of General Internal Medicine and En- docrinology, Leiden University Medical Center, Leiden, The Nether- lands. 2 Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands. 3 Department of Radiology, Division of MRI Research, Johns Hopkins University Medical School, Baltimore, Maryland, USA. 4 Department of Medical Statistics and Bio-Informatics, Leiden Univer- sity Medical Center, Leiden, The Netherlands. 5 Image Processing, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands. *Address reprint requests to: R.A.D., Vascular Medicine (C4-R), Dept. of General Internal Medicine and Endocrinology, Leiden University Med- ical Center, PO Box 9600, 2300 RC Leiden, The Netherlands. E-mail: R.Alizadehdehnavi@lumc.nl Received April 22, 2006; Accepted December 6, 2006. DOI 10.1002/jmri.20904 Published online in Wiley InterScience (www.interscience.wiley.com). JOURNAL OF MAGNETIC RESONANCE IMAGING 25:1035–1043 (2007) © 2007 Wiley-Liss, Inc. 1035