King's College London, Osteoporosis Screening and Research Unit, Guy's Hospital, London, UK.
J Nucl Med. 2011 Nov;52(11):1748-55. doi: 10.2967/jnumed.111.093195. Epub 2011 Oct 11.
The planning of research studies requires an understanding of the minimum number of subjects required. The aim of this study was to evaluate different methods of analyzing (18)F-fluoride PET ((18)F(-) PET) dynamic spine scans to find the approach that requires the smallest sample size to detect a statistically significant response to treatment.
Eight different approaches to (18)F(-) PET analysis (3 variants of the Hawkins 3-tissue compartmental model, 3 variants of spectral analysis, deconvolution, and Patlak analysis) were used to evaluate the fluoride plasma clearance to bone mineral (K(i)). Standardized uptake values (SUVs) were also studied. Data for 20 women who had (18)F(-) PET spine scans at 0, 6, and 12 mo after stopping long-term bisphosphonate treatment were used to compare precision errors. Data for 18 women who had scans at baseline and 6 mo after starting teriparatide treatment were used to compare response to treatment.
The 4 approaches that fitted the rate constant k(4) describing the reverse flow of (18)F from bone as a free variable showed close agreement in K(i) values, with correlation coefficients greater than 0.97. Their %CVs were 14.4%-14.8%, and treatment response to teriparatide was 23.2%-23.8%. The 3 methods that assumed k(4) = 0 gave K(i) values 20%-25% lower than the other methods, with correlation coefficients of 0.83-0.94, percentage coefficients of variation (%CVs) of 12.9%-13.3%, and treatment response of 25.2%-28.3%. A Hawkins model with k(4) = 0.01 min(-1) did not perform any better (%CV, 14.2%; treatment response, 26.1%). Correlation coefficients between SUV and the different K(i) methods varied between 0.60 and 0.65. Although SUV gave the best precision (%CV, 10.1%), the treatment response (3.1%) was not statistically significant.
Methods that calculated K(i) assuming k(4) = 0 required fewer subjects to demonstrate a statistically significant response to treatment than methods that fitted k(4) as a free variable. Although SUV gave the smallest precision error, the absence of any significant changes make it unsuitable for examining response to treatment in this study.
本研究旨在评估分析氟-18 （ 18 ） F-氟化物正电子发射断层扫描（ 18 （ F ） - 正电子发射断层扫描）动态脊柱扫描的不同方法，以找到需要最小样本量来检测治疗有统计学意义反应的方法。
使用 8 种不同的 18 （ F ） - 氟化物正电子分析方法（ Hawkins 3 组织室模型的 3 种变体，光谱分析的 3 种变体，反卷积和 Patlak 分析）来评估氟化物血浆清除到骨矿物质（ K i ）的情况。还研究了标准化摄取值（ SUV ）。使用 20 名女性在停止长期双膦酸盐治疗后 0 、 6 和 12 个月的 18 （ F ） - 正电子脊柱扫描数据来比较精度误差。使用 18 名女性在基线和开始特立帕肽治疗 6 个月后的扫描数据来比较对治疗的反应。
拟合描述 18 （ F ）从骨骼中反向流动的速率常数 k 4 的 4 种方法将 K i 值紧密一致，相关系数大于 0.97 。它们的变异系数（ %CV ）为 14.4%-14.8% ，特立帕肽治疗的反应为 23.2%-23.8% 。假设 k 4 = 0 的 3 种方法得到的 K i 值比其他方法低 20%-25% ，相关系数为 0.83-0.94 ，变异系数（ %CV ）为 12.9%-13.3% ，治疗反应为 25.2%-28.3% 。 k 4 = 0.01min -1 的 Hawkins 模型表现不佳（ %CV ， 14.2% ；治疗反应， 26.1% ）。 SUV 与不同 K i 方法之间的相关系数在 0.60 到 0.65 之间变化。虽然 SUV 提供了最佳的精度（ %CV ， 10.1% ），但治疗反应（ 3.1% ）无统计学意义。
假设 k 4 = 0 计算 K i 的方法比拟合 k 4 为自由变量的方法需要更少的受试者来证明治疗有统计学意义的反应。虽然 SUV 提供了最小的精度误差，但没有任何显著变化使其不适合在本研究中检查对治疗的反应。
