Wehrli F W, Hwang S N, Song H K
Department of Radiology, University of Pennsylvania Medical Center, Philadelphia 19104, USA.
Technol Health Care. 1998 Dec;6(5-6):307-20.
This article reviews recent progress in magnetic resonance microimaging of cancellous bone in vitro and in vivo from the perspective of the authors' laboratory. It is shown that in particular in vivo the key technical prerequisites to satisfy are: (i) achieving sufficient signal-to-noise ratio (SNR) to allow for adequate spatial resolution; (ii) the image processing algorithms have to be robust enough to provide accurate structural information in the limited spatial resolution regime, i.e., in the presence of inevitable partial volume blurring and noise. The practical lower limit of voxel size in vivo was found to be about 6 x 10(-3) mm3 in the radius, and about 10(-4) mm3 for small specimens in vitro with state-of-the-art equipment and scan times of 10 and 30 minutes, resp., and SNR approximately 10. Finally, data are presented highlighting the potential of these methods for predicting the bone's elastic modulus in vitro and fracture risk in vivo.
本文从作者所在实验室的角度回顾了松质骨磁共振显微成像在体外和体内研究的最新进展。结果表明，特别是在体内，需要满足的关键技术前提是：（i）获得足够的信噪比（SNR）以实现足够的空间分辨率；（ii）图像处理算法必须足够稳健，以便在有限的空间分辨率条件下，即在存在不可避免的部分容积模糊和噪声的情况下，提供准确的结构信息。在体内，使用最先进的设备，扫描时间分别为10分钟和30分钟，信噪比约为10时，发现桡骨体内体素大小的实际下限约为6×10⁻³立方毫米，体外小样本约为10⁻⁴立方毫米。最后，给出的数据突出了这些方法在体外预测骨弹性模量和体内预测骨折风险方面的潜力。
