Biopsy-based calibration of T2* magnetic resonance for estimation of liver iron concentration and comparison with R2 Ferriscan.
Biopsy-based calibration of T2* magnetic resonance for estimation of liver iron concentration and comparison with R2 Ferriscan.
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DOI：
10.1186/1532-429x-16-40
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发表时间：
2014-06-10
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影响因子：
--
通讯作者：
Porter JB
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作者：
Garbowski MW;Carpenter JP;Smith G;Roughton M;Alam MH;He T;Pennell DJ;Porter JB
有必要简化肝脏铁浓度（LIC）的非侵入性测量，以便明确推断与铁过载的肝脏和肝外并发症相关的体内铁水平。自从首次使用概念验证T2* 序列证明活检LIC和肝脏磁共振（MR）之间的反比关系以来，MR技术已经取得了显着进步，具有更短的最小回波时间，更近的回波间隔和恒定的重复时间。这些重要的进展使肝脏T2* 的计算更加准确，特别是在高LIC患者中。在这里，我们使用了一个优化的肝脏T2* 序列校准对50个肝活检样本的25例输血性含铁血黄素沉着症患者使用普通最小二乘线性回归，并评估了方法的重现性在96个扫描LIC范围高达42毫克/克干重（dw）使用Bland-Altman图。使用混合模型线性回归，我们比较了新的T2*-LIC与R2-LIC（Ferriscan）对54例输血性含铁血黄素沉着症患者的92次扫描，并使用Bland-Altman方法检查方法一致性。ln（T2*）和ln（LIC）之间的强线性相关性导致校准方程LIC = 31.94（T2*）-1.014。这产生的LIC值比概念验证T2* 方法高约2.2倍。在92次扫描中将这种新的T2*-LIC与R2-LIC（Ferriscan）技术进行比较，我们观察到两种方法之间的密切关系，值高达10 mg/g dw，但方法一致性较差。针对肝脏活检的T2* 的新校准以可重现的方式估计LIC，将概念验证校准校正2.2倍。由于一致性较差，两种方法应分别用于诊断或排除铁蛋白升高患者的肝脏铁超载。
There is a need to standardise non-invasive measurements of liver iron concentrations (LIC) so clear inferences can be drawn about body iron levels that are associated with hepatic and extra-hepatic complications of iron overload. Since the first demonstration of an inverse relationship between biopsy LIC and liver magnetic resonance (MR) using a proof-of-concept T2* sequence, MR technology has advanced dramatically with a shorter minimum echo-time, closer inter-echo spacing and constant repetition time. These important advances allow more accurate calculation of liver T2* especially in patients with high LIC. Here, we used an optimised liver T2* sequence calibrated against 50 liver biopsy samples on 25 patients with transfusional haemosiderosis using ordinary least squares linear regression, and assessed the method reproducibility in 96 scans over an LIC range up to 42 mg/g dry weight (dw) using Bland-Altman plots. Using mixed model linear regression we compared the new T2*-LIC with R2-LIC (Ferriscan) on 92 scans in 54 patients with transfusional haemosiderosis and examined method agreement using Bland-Altman approach. Strong linear correlation between ln(T2*) and ln(LIC) led to the calibration equation LIC = 31.94(T2*)-1.014. This yielded LIC values approximately 2.2 times higher than the proof-of-concept T2* method. Comparing this new T2*-LIC with the R2-LIC (Ferriscan) technique in 92 scans, we observed a close relationship between the two methods for values up to 10 mg/g dw, however the method agreement was poor. New calibration of T2* against liver biopsy estimates LIC in a reproducible way, correcting the proof-of-concept calibration by 2.2 times. Due to poor agreement, both methods should be used separately to diagnose or rule out liver iron overload in patients with increased ferritin.