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Purpose To quantify the cervical muscle volume variation by means of three-dimensional reconstruction from MRI images. Materials and Methods Sixteen subjects were scanned using a Philips MRI scanner, including 11 men and 5 women, aged from 23 to 33 years, weighting between 49–80 kg. The deformation of a parametric specific object method was used to develop three-dimensional muscle models from contours on a small number of MRI images. Six subjects were reconstructed by two observers for evaluating the reliability by means of intraclass correlation coefficient (ICC). The results were also compared with in vivo measurement on a single specimen from a reference literature. The difference in left and right muscles volumes was assessed with a paired Wilcoxon signed rank test. Results The results showed good reliability by means of ICC study and were consistent with the in vivo specimen measurements. The left and right paired muscle volumes showed no significant difference. Interindividual variance was large that could reach 364 cm3, but the ratio of a given muscle volume to the total volume was less variable, always lower than 13%. The maximum cross sectional areas of cervical muscles varied greatly between individuals and the maximum values were mostly found at the C6–C7 level. Conclusion This study provides initial results which could be used as reference data for clinical evaluation and biomechanical model development. J. Magn. Reson. Imaging 2014;39:1411–1416. © 2013 Wiley Periodicals, Inc.

Purpose To establish a new imaging technique using dynamic MRI three-dimensional (3D) volumetric acquisition in real-time, on six normal shoulders for the analysis of the 3D shoulder kinematics during continuous motion. Materials and Methods At first, a standard static acquisition was performed. Then, fast images were obtained with a multi-slice 3D balanced gradient echo sequence to get a real time series during the initial phase of shoulder abduction. Subsequently, the images were reconstructed; registered and the translational patterns of the humeral head relative to the glenoid and the size of the subacromial space were calculated. Additionally, the intraobserver reproducibility was tested. Results The maximal abduction was on average 43° (30° to 60°) and the mean width of the subacromial space was 7.7 mm (SD: ± 1.2 mm). Difference between extreme values and average values was low, respectively 2.5 mm on X-axis, 2 mm on Y-axis, 1.4 mm for the width of the subacromial space and 1.2° for the measure of the glenohumeral abduction. Conclusion This study reported a dynamic MRI protocol for the monitoring of shoulder 3D kinematics during continuous movement. The results suggest that there is no superior shift of the humeral head during the first phase of abduction. J. Magn. Reson. Imaging 2014;39:729–734. © 2013 Wiley Periodicals, Inc.

Purpose To compare the precision of four methods to estimate the volume of quadriceps muscles using axial MRI. Materials and Methods Entire legs of 10 healthy young subjects were scanned using a 1.5 Tesla magnetic resonance imaging scanner and 4-mm-thick sections without any gaps. Quadriceps muscles were outlined on all of the slices to obtain the MRI reference standard measure of quadriceps muscle volume. This MRI reference standard was compared with the volume estimated using (i) the truncated cone formula, (ii) the Cavalieri method, (iii) a cubic spline interpolation of missing cross sectional areas, and, (iv) the deformation of a parametric specific object. For each method, 3 to 21 slices were used. Results The average volume error was significantly (P < 0.001) different in comparing the four methods (4.4%, 2.3%, 1.1%, and 1.2%, respectively). In addition, the number of slices required to reach a given volume error was significantly (P < 0.001) different across all methods (respectively, 12, 9, 5, and 7 slices required to reach a volume error of 1.1%). Conclusion While methods based on interpolation and deformation of a parametric specific object have not been used in literature, these two methods are the most precise approaches to reach a given level of precision. J. Magn. Reson. Imaging 2009;30:1116–1123. © 2009 Wiley-Liss, Inc.