Head-to-head comparison of eight late gadolinium-enhanced cardiac MR (LGE CMR) sequences at 1.5 tesla: from bench to bedside.

PURPOSE: To compare-theoretically and experimentally-clinically available two-dimensional/three-dimensional (2D/3D), breathhold and non-breathhold, inversion-recovery (IR) gradient-echo (GRE) sequences used to differentiate between nonviable injured and normal myocardium with late gadolinium-enhanced techniques (IR-GRE2D sequence is used as a reference), and to evaluate their respective clinical benefit. MATERIALS AND METHODS: Six breathhold (2D-IR-GRE, 3D-IR-GRE, balanced steady-state free precession 2D-IR-bSSFP and 3D-IR-bSSFP, phase-sensitive 2D-PSIR-GRE, and 2D-PSIR-bSSFP) and two non-breathhold late gadolinium-enhanced techniques (single-shot 2D-ssbSSFP and 2D-PSIR-ssbSSFP) were consecutively performed in 32 coronary artery disease patients with chronic myocardial infarction. Qualitative assessment and manual planimetry were performed by two independent observers. Quantitative assessment was based on percentage signal intensity elevation between injured and normal myocardium and contrast-to-noise ratio. Theoretical simulations were compared with experimental measurements performed on phantoms with various concentrations of gadolinium. RESULTS: The 3D-IR-GRE image quality appeared better than the other 2D and 3D sequences, showing better delineation of complex nontransmural lesions, with significantly higher percentage signal intensity and contrast-to-noise ratio. PSIR techniques appeared more limited in differentiating sub-endocardial lesions and intracavity blood pool, but in all other cases were comparable to the other techniques. Single-shot PSIR-ssbSSFP appeared to be a valuable alternative technique when breathhold cannot be achieved. CONCLUSION: We recommend 3D-IR-GRE as the method of choice for late gadolinium-enhanced cardiac magnetic resonance imaging in clinical practice.

The reliability of high resolution MRI in the measurement of early stage carotid wall thickening.

PURPOSE: To study the repeatability of common carotid mean wall thickness (MWT) measured with high resolution MRI, in comparison with intima media thickness (IMT) assessed by ultrasound and to investigate the relative capabilities of these two modalities. MATERIALS AND METHODS: Ten healthy volunteers and 10 subjects with carotid artery atherosclerosis were imaged with both high resolution MRI and US. Measurement of both MWT and IMT was performed by three blinded observers. Intra- and inter-observer repeatability was calculated and a Bland-Altman plot used to compare IMT and MWT. Circumferential variation in arterial wall thickness was also evaluated. RESULTS: Intra- and inter-observer repeatability were comparable between IMT and MWT. The Bland-Altman plot showed a difference between IMT and MWT in controls with a trend towards equivalence in atherosclerotic patients. Analysis of circumferential variation in wall thickness by MRI identified greater focal thickening in patients compared with controls (p<0.001), which was not evident with ultrasound (p=0.98). CONCLUSION: MRI and ultrasound have similar repeatability for the assessment of carotid wall thickness. There are differences between MWT and IMT, potentially due to the inclusion of the adventitia by MRI which, in addition to better detection of focal thickening, may provide a more complete estimation of early stage atherosclerosis.