Cicuttini Flavia, Morris Kevin F, Glisson Michael, Wluka Anita E
Department of Epidemiology and Preventive Medicine, Monash University, Alfred Hospital, Prahran, Victoria 3181, Australia.
J Rheumatol. 2004 Dec;31(12):2444-8.
The optimal magnetic resonance image (MRI) slice thickness required to assess cartilage volume accurately and efficiently in cross-sectional and longitudinal studies is unknown. We compared cartilage volume measured from MRI of the knees using different slice thicknesses (1.5 to 7.5 mm) and assessed longitudinal change.
A total of 123 subjects with osteoarthritis had baseline and followup MRI on their symptomatic knee at 2 years. Medial and lateral tibial cartilage volumes were calculated using increasing slice thickness by extracting each second, third, fourth, or fifth slice area to calculate total volume, which was compared to the "gold standard" volume calculated from the original 1.5 mm slices.
There was little difference in the average medial and lateral tibial cartilage volume observed as the slice thickness increased from 1.5 to 7.5 mm; medial tibial cartilage volume ranged from 1750 microl to 1787 microl and lateral tibial cartilage volume ranged from 1949 microl to 2007 microl. There was also little absolute difference in the average change in medial and lateral tibial cartilage volume measured over 2 years. However, with increasing slice thickness, there was a decreased correlation between the tibial cartilage volume change calculated from the increased slice thickness, with the lowest correlation being 0.77 (p < 0.001) when the lateral cartilage volume calculated from the 7.5 mm slice was compared to the 1.5 mm slices.
Increasing slice thickness may provide sufficiently accurate measurement of tibial cartilage volume and change over time in some studies. This would result in reduction in MRI scanning and postimaging processing time, which has the potential of increasing the feasibility of this technique.
在横断面和纵向研究中，准确且高效地评估软骨体积所需的最佳磁共振成像（MRI）层厚尚不清楚。我们比较了使用不同层厚（1.5至7.5毫米）的膝关节MRI测量的软骨体积，并评估了纵向变化。
共有123名骨关节炎患者在其有症状的膝关节处进行了基线检查，并在2年后进行了随访MRI检查。通过提取每隔第二、第三、第四或第五个切片区域来计算内侧和外侧胫骨软骨体积，以增加层厚，从而计算总体积，并将其与从原始1.5毫米切片计算出的“金标准”体积进行比较。
当层厚从1.5毫米增加到7.5毫米时，观察到的内侧和外侧胫骨软骨平均体积差异不大；内侧胫骨软骨体积范围为1750微升至1787微升，外侧胫骨软骨体积范围为1949微升至2007微升。在2年期间测量的内侧和外侧胫骨软骨体积的平均变化的绝对差异也很小。然而，随着层厚增加，根据增加的层厚计算出的胫骨软骨体积变化之间的相关性降低，当将从7.5毫米切片计算出的外侧软骨体积与1.5毫米切片进行比较时，最低相关性为0.77（p < 0.001）。
在某些研究中，增加层厚可能会提供足够准确的胫骨软骨体积测量以及随时间的变化。这将减少MRI扫描和成像后处理时间，有可能提高该技术的可行性。
