Dose correction for post-contrast T1 mapping of the heart: the MESA study.
Dose correction for post-contrast T1 mapping of the heart: the MESA study.
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对比后T1映射的剂量校正心脏：MESA研究。
DOI：
10.1007/s10554-015-0754-3
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发表时间：
2016-02
期刊：
影响因子：
--
通讯作者：
Bluemke DA
中科院分区：
文献类型：
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作者：
Gai ND;Sandfort V;Liu S;Lima JAC;Bluemke DA
对比后心肌 T1 (T1myo,c) 值已被证明对心肌纤维化敏感。最近的研究表明，从 T1myo,c 和细胞外体积分数 (ECV) 获得的结果在纤维化百分比方面存在差异。通过探索血浆量和 T1myo,c 之间的关系，可以解释差异的根本原因。此外，基于体重指数、年龄和性别的剂量管理可以减轻结果的差异。 T1myo,c 的受试者间比较需要调整剂量（以 mmol/kg 为单位）、时间和肾小球滤过率 (GFR)。根据血液/血浆体积（PV）反映的瘦肌肉质量进一步调整有效剂量。对 MESA 研究中 605 名接受过对比前和对比后 T1 映射的受试者的测试案例进行了研究。根据血浆容量调整剂量之前和之后，比较患有和不患有代谢综合征 (MetS) 的受试者、吸烟和不吸烟受试者以及患有和不患有糖耐量受损的受试者之间的 T1myo,c 值。还进行了与 ECV（与剂量无关）、对比前心肌 T1 和血液标准化心肌 T1 值的比较，以验证校正。当前吸烟者和既往吸烟者之间的 T1myo,c（血浆容量校正后）和 ECV 存在显着差异（p 值分别为 0.017 和 0.01），但校正前的 T1myo,c 没有显着差异（p = 0.12）。在根据血浆容量进行剂量调整之前，MetS 组和非 MetS 组之间 T1myo,c 的 p 值 < 0.001，有和没有葡萄糖耐受不良受试者之间的 p 值是 0.13；调整 PV 后，p 值为 0.63 和 0.99。相应的 ECV p 值分别为 0.44 和 0.99。总体而言，与其他测量结果（校正前的 T1myo,c 和血液/血浆 T1 值标准化心肌）相比，ECV 结果显示与 PV 校正的 T1myo,c（p 值的平均绝对差 = 0.073）和对比前心肌 T1 具有最佳一致性。基于体重的对比剂量（以 mmol/kg 为单位）会导致 T1 值出现偏差，从而导致错误的结论。根据血浆量调整瘦肌肉质量后，T1myo,c 的结果与 ECV 得出的结果一致。此外，可以采用根据体重指数（BMI）、年龄、性别和血细胞比容调整的修改后的等效剂量进行定量成像。
Post-contrast myocardial T1 (T1myo,c) values have been shown to be sensitive to myocardial fibrosis. Recent studies have shown differences in results obtained from T1myo,c and extracellular volume fraction (ECV) with respect to percentage fibrosis. By exploring the relationship between blood plasma volume and T1myo,c, the underlying basis for the divergence can be explained. Furthermore, dose administration based on BMI, age and gender can mitigate the divergence in results. Inter-subject comparison of T1myo,c required adjustment for dose (in mmol/kg), time and glomerular filtration rate (GFR). Further adjustment for effective dose based on lean muscle mass reflected by blood/plasma volume (PV) was performed. A test case of 605 subjects from the MESA study who had undergone pre and post-contrast T1 mapping was studied. T1myo,c values were compared between subjects with and without metabolic syndrome (MetS), between smoking and non-smoking subjects, and subjects with and without impaired glucose tolerance, before and after dose adjustment based on plasma volume. Comparison with ECV (which is dose independent), pre-contrast myocardial T1 and blood normalized myocardial T1 values was also performed to validate the correction. There were significant differences in T1myo,c (post plasma volume correction) and ECV between current and former smokers (p-value 0.017 and 0.01, respectively) but not T1myo,c prior to correction (p = 0.12). Prior to dose adjustment for plasma volume, p-value was < 0.001 for T1myo,c between MetS and non-MetS groups and was 0.13 between subjects with and without glucose intolerance; after adjustment for PV, p value was 0.63 and 0.99. Corresponding ECV p values were 0.44 and 0.99, respectively. Overall, ECV results showed the best agreement with PV corrected T1myo,c (mean absolute difference in p values = 0.073) and pre-contrast myocardial T1 in comparison with other measures (T1myo,c prior to correction and blood/plasma T1 value normalized myocardium). Weight-based contrast dosing administered in mmol/kg results in a bias in T1 values which can lead to erroneous conclusions. After adjustment for lean muscle mass based on plasma volume, results from T1myo,c were in line with ECV derived results. Furthermore, the use of a modified equivalent dose adjusted for body mass index (BMI), age, sex and hematocrit can be adopted for quantitative imaging.