Turk N, Kastelan D, Cukovic-Cavka S, Kraljevic I, Korsic M, Vucelic B
Department of Gastroenterology, University Department of Medicine, Zagreb University Hospital Center, Zagreb, Croatia.
Ultrasound Med Biol. 2007 Jun;33(6):863-9. doi: 10.1016/j.ultrasmedbio.2007.01.003. Epub 2007 Apr 16.
A high incidence of bone disease in patients with inflammatory bowel disease (IBD) requires frequent monitoring of skeletal status and, for that reason, evaluation of radiation-free technology is an issue of interest. Our objective was to appraise the parameters of calcaneal quantitative ultrasound (QUS): broadband ultrasound attenuation (BUA), speed of sound (SOS) and stiffness index (QUI), and establish their t-score values to investigate discriminatory ability of QUS in IBD patients with metabolic bone disease. The study included 126 patients (Crohn's disease [n = 94] and ulcerative colitis [n = 32]), and 228 age- and sex-matched healthy volunteers. Bone status was evaluated on the same day by calcaneal QUS and dual-energy x-ray absorptiometry (DXA) at spine (L1-L4) and total hip. All QUS measurements were lower in patients compared with healthy controls (BUA p < 0.001; SOS p < 0.001; QUI p < 0.001) and correlated significantly but inversely with disease duration (r = -0.3, p = 0.002). There was no difference with respect to type of disease (Crohn's disease or ulcerative colitis) or corticosteroid therapy. All three QUS t-scores were significantly lower in patients who had previously sustained fragile fractures (n = 28) than in those without fracture in their history (n = 98) (t-scores: BUA -2.0 vs. -1.3, p = 0.008; SOS -2.1 vs. -1.4, p = 0.02: QUI -2.3 vs. -1.5, p = 0.009). Axial DXA was not significantly different between the fracture and nonfracture patients (-1.7 vs. -1.2, p = 0.1), whereas total hip DXA showed a discriminatory power between the two (-1.6 vs. -0.7, p = 0.001). Patients with t-score < -1.0 scanned by DXA were classified as bone disease. The sensitivity of QUS to identify bone disease was 93% and specificity 63%. The sensitivity of QUS to detect osteopenia was 84% and 72% for osteoporosis. Alternatively, lower negative QUS t-score cutoff <or= -1.8 identified 83% of osteoporosis at lumbar spine and 100% at total hip. All three QUS variables had t-scores less than -1.8 when osteoporosis was detected at both spine and hip. However, the subgroup of IBD patients with QUI t-score cutoff <or= -1.8 still included 26% of individuals with normal bone status. Calcaneal QUS measurements may identify patients with IBD who are at a higher risk of fracture independently of DXA measurements. However, QUS showed poor agreement with bone status scanned by DXA and a low discriminatory power between osteopenia and osteoporosis.
炎症性肠病（IBD）患者中骨病的高发病率需要对骨骼状况进行频繁监测，因此，对无辐射技术的评估是一个备受关注的问题。我们的目的是评估跟骨定量超声（QUS）的参数：宽带超声衰减（BUA）、声速（SOS）和硬度指数（QUI），并确定它们的t值，以研究QUS在患有代谢性骨病的IBD患者中的鉴别能力。该研究纳入了126例患者（克罗恩病[n = 94]和溃疡性结肠炎[n = 32]）以及228名年龄和性别匹配的健康志愿者。在同一天通过跟骨QUS以及脊柱（L1-L4）和全髋部的双能X线吸收法（DXA）对骨骼状况进行评估。与健康对照组相比，患者的所有QUS测量值均较低（BUA p < 0.001；SOS p < 0.001；QUI p < 0.001），并且与疾病持续时间显著负相关（r = -0.3，p = 0.002）。在疾病类型（克罗恩病或溃疡性结肠炎）或皮质类固醇治疗方面没有差异。既往有脆性骨折的患者（n = 28）的所有三个QUS t值均显著低于无骨折病史的患者（n = 98）（t值：BUA -2.0对 -1.3，p = 0.008；SOS -2.1对 -1.4，p = 0.02；QUI -2.3对 -1.5，p = 0.009）。骨折患者和未骨折患者之间轴向DXA无显著差异（-1.7对 -1.2，p = 0.1），而全髋部DXA在两者之间显示出鉴别能力（-1.6对 -0.7，p = 0.001）。DXA扫描t值 < -1.0的患者被归类为患有骨病。QUS识别骨病的敏感性为93%，特异性为63%。QUS检测骨质减少的敏感性为84%，检测骨质疏松症的敏感性为72%。或者，较低的负QUS t值临界值≤ -1.8可识别出83%的腰椎骨质疏松症患者和100%的全髋部骨质疏松症患者。当在脊柱和髋部均检测到骨质疏松症时，所有三个QUS变量的t值均小于 -1.8。然而，QUI t值临界值≤ -1.8的IBD患者亚组中仍有26%的个体骨骼状况正常。跟骨QUS测量可以独立于DXA测量识别出骨折风险较高的IBD患者。然而，QUS与DXA扫描的骨骼状况一致性较差，并且在骨质减少和骨质疏松症之间的鉴别能力较低。
