Swinford R R, Warden S J
Department of Physical Therapy, School of Health and Rehabilitation Sciences, Indiana University, 1140 W. Michigan St., CF-326, Indianapolis, IN 46202, USA.
Osteoporos Int. 2010 Nov;21(11):1863-70. doi: 10.1007/s00198-009-1151-3. Epub 2010 Jan 6.
Few studies have investigated factors influencing the precision of peripheral quantitative computed tomography (pQCT) measures. This study found time between repeat scans and subject anthropometric characteristics to influence short-term precision of pQCT-derived measures in the lower leg. These findings have implications for both investigators and clinicians utilizing pQCT outcomes.
Peripheral quantitative computed tomography (pQCT) is increasingly being used to investigate musculoskeletal changes associated with age, disease and/or intervention. Precision of pQCT measures is of paramount importance in this endeavor. This study aimed to establish the short-term precision of pQCT-derived musculoskeletal measures of the lower leg and investigate factors influencing this precision.
Thirty healthy subjects had a series of six pQCT scans of the lower leg (66% of tibial length proximal from its distal end) performed on two separate days by two different testers. The influences of different testers, time between repeat scans, and subject anthropometric characteristics on precision were explored.
Overall precision error (root mean square) increased from bone (<1%) to muscle (<1.5%) to fat (3%). The two testers were equally precise in performing pQCT measures; however, precision error increased when repeat scans were repeated 1 week apart as opposed to on the same day. Subject anthropometric characteristics influenced precision errors with the general finding being that an increase in subject size was associated with less precise pQCT measures.
pQCT is a relatively precise technique for the assessment of bone and muscle, but precision is influenced by time between repeat scans and subject anthropometric characteristics. Investigators and clinicians need to be aware of these factors influencing pQCT outcomes as they may influence statistical power in clinical studies and the characterization of change in individual patients.
很少有研究调查影响外周定量计算机断层扫描（pQCT）测量精度的因素。本研究发现重复扫描之间的时间以及受试者人体测量学特征会影响pQCT得出的小腿测量结果的短期精度。这些发现对使用pQCT结果的研究者和临床医生均有启示。
外周定量计算机断层扫描（pQCT）越来越多地用于研究与年龄、疾病和/或干预相关的肌肉骨骼变化。在这项工作中，pQCT测量的精度至关重要。本研究旨在确定pQCT得出的小腿肌肉骨骼测量结果的短期精度，并调查影响该精度的因素。
30名健康受试者在两天内由两名不同的测试者对小腿（从其远端起胫骨长度的66%处）进行了一系列六次pQCT扫描。探讨了不同测试者、重复扫描之间的时间以及受试者人体测量学特征对精度的影响。
总体精度误差（均方根）从骨骼（<1%）到肌肉（<1.5%）再到脂肪（3%）逐渐增加。两名测试者在进行pQCT测量时精度相同；然而，与同一天重复扫描相比，当重复扫描间隔1周进行时，精度误差会增加。受试者人体测量学特征影响精度误差，一般发现是受试者体型增大与pQCT测量精度降低相关。
pQCT是评估骨骼和肌肉的一种相对精确的技术，但精度受重复扫描之间的时间和受试者人体测量学特征影响。研究者和临床医生需要意识到这些影响pQCT结果的因素，因为它们可能影响临床研究的统计效力以及个体患者变化的特征描述。
