The recently developed multi‐acquisition with variable resonance image combination (MAVRIC) and slice‐encoding metal artifact correction (SEMAC) techniques can significantly reduce image artifacts commonly encountered near embedded metal hardware. These artifact reductions are enabled by applying alternative spectral and spatial‐encoding schemes to conventional spin‐echo imaging techniques. Here, the MAVRIC and SEMAC concepts are connected and discussed. The development of a hybrid technique that utilizes strengths of both methods is then introduced. The presented technique is shown capable of producing minimal artifact, high‐resolution images near total joint replacements in a clinical setting. Magn Reson Med, 2010.

A comprehensive literature review was performed on liver intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) technique and its applications. Heterogeneous data have been reported. IVIM parameters are magnetic field strength dependent to a mild extent. A lower Dslow (D) value at 3 T than at 1.5 T and higher perfusion fraction (PF) value at 3 T than at 1.5 T were noted. An increased number of b values are associated with increased IVIM parameter measurement accuracy. With the current status of art, IVIM technique is not yet capable of detecting early stage liver fibrosis and diagnosing liver fibrosis grades, nor can it differentiate liver tumors. Though IVIM parameters show promise for tumor treatment monitoring, till now how PF and Dfast (D*) add diagnostic value to Dslow or apparent diffusion coefficient (ADC) remains unclear. This paper shows the state-of-art IVIM MR technique is still not able to offer reliable measurement for liver. More works on the measurement robustness are warranted as they are essential to justify follow-up clinical studies on patients.

Purpose To develop a robust sequence that combines T_1ρ and T₂ quantifications and to examine the in vivo repeatability and diurnal variation of T_1ρ and T₂ quantifications in knee cartilage. Materials and Methods Six healthy volunteers were scanned in the morning and afternoon on 2 days using a combined T_1ρ and T₂ quantification sequence developed in this study. Repeatability of T_1ρ and T₂ quantification was estimated using root‐mean‐square coefficients‐of‐variation (RMS‐CV). T_1ρ and T₂ values from morning scans were compared to those from afternoon scans using paired t‐tests. Results The overall RMS‐CV of in vivo T_1ρ and T₂ quantification was 5.3% and 5.2%, respectively. The RMS‐CV of am scans was 4.2% and 5.0% while the RMS‐CV of pm scans was 6.0% and 6.3% for T_1ρ and T₂, respectively. No significant difference was found between T_1ρ or T₂ values in the morning and in the afternoon. Conclusion A sequence that combines T_1ρ and T₂ quantification with scan time less than 10 minutes and is robust to B₀ and B₁ inhomogeneity was developed with excellent repeatability. For a cohort with low‐level daily activity, although no significant diurnal variation of cartilage MR relaxation times was observed, the afternoon scans had inferior repeatability compared to morning scans. J. Magn. Reson. Imaging 2014;39:1287–1293 . © 2013 Wiley Periodicals, Inc .