心肌T2 mapping显示志愿者存在年龄和性别相关差异。
Myocardial T2 mapping reveals age- and sex-related differences in volunteers.
作者信息
Bönner Florian, Janzarik Niko, Jacoby Christoph, Spieker Maximilian, Schnackenburg Bernhard, Range Felix, Butzbach Britta, Haberkorn Sebastian, Westenfeld Ralf, Neizel-Wittke Mirja, Flögel Ulrich, Kelm Malte
机构信息
Department of Cardiology, Pulmonology and Vascular Medicine, Heinrich Heine University, Medical Faculty, Moorenstraße 5, Düsseldorf, 40225, Germany.
出版信息
J Cardiovasc Magn Reson. 2015 Feb 6;17(1):9. doi: 10.1186/s12968-015-0118-0.
BACKGROUND
T2 mapping indicates to be a sensitive method for detection of tissue oedema hidden beyond the detection limits of T2-weighted Cardiovascular Magnetic Resonance (CMR). However, due to variability of baseline T2 values in volunteers, reference values need to be defined. Therefore, the aim of the study was to investigate the effects of age and sex on quantitative T2 mapping with a turbo gradient-spin-echo (GRASE) sequence at 1.5 T. For that reason, we studied sensitivity issues as well as technical and biological effects on GRASE-derived myocardial T2 maps. Furthermore, intra- and interobserver variability were calculated using data from a large volunteer group.
METHODS
GRASE-derived multiecho images were analysed using dedicated software. After sequence optimization, validation and sensitivity measurements were performed in muscle phantoms ex vivo and in vivo. The optimized parameters were used to analyse CMR images of 74 volunteers of mixed sex and a wide range of age with typical prevalence of hypertension and diabetes. Myocardial T2 values were analysed globally and according to the 17 segment model. Strain-encoded (SENC) imaging was additionally performed to investigate possible effects of myocardial strain on global or segmental T2 values.
RESULTS
Ex vivo studies in muscle phantoms showed, that GRASE-derived T2 values were comparable to those acquired by a standard multiecho spinecho sequence but faster by a factor of 6. Besides that, T2 values reflected tissue water content. The in vivo measurements in volunteers revealed intra- and interobserver correlations with R2=0.91 and R2=0.94 as well as a coefficients of variation of 2.4% and 2.2%, respectively. While global T2 time significantly decreased towards the heart basis, female volunteers had significant higher T2 time irrespective of myocardial region. We found no correlation of segmental T2 values with maximal systolic, diastolic strain or heart rate. Interestingly, volunteers´ age was significantly correlated to T2 time while that was not the case for other coincident cardiovascular risk factors.
CONCLUSION
GRASE-derived T2 maps are highly reproducible. However, female sex and aging with typical prevalence of hypertension and diabetes were accompanied by increased myocardial T2 values. Thus, sex and age must be considered as influence factors when using GRASE in a diagnostic manner.
背景
T2 映射被证明是一种检测组织水肿的敏感方法，这种水肿隐藏在 T2 加权心血管磁共振（CMR）的检测极限之外。然而，由于志愿者基线 T2 值存在变异性，需要定义参考值。因此，本研究的目的是在 1.5T 场强下，使用涡轮梯度自旋回波（GRASE）序列研究年龄和性别对定量 T2 映射的影响。出于这个原因，我们研究了 GRASE 衍生的心肌 T2 图的敏感性问题以及技术和生物学效应。此外，使用来自大量志愿者组的数据计算了观察者内和观察者间的变异性。
方法
使用专用软件分析 GRASE 衍生的多回波图像。在序列优化后，在离体和活体肌肉模型中进行了验证和敏感性测量。使用优化后的参数分析了 74 名不同性别、年龄范围广泛且具有典型高血压和糖尿病患病率的志愿者的 CMR 图像。对心肌 T2 值进行整体分析，并根据 17 节段模型进行分析。另外进行了应变编码（SENC）成像，以研究心肌应变对整体或节段 T2 值的可能影响。
结果
在肌肉模型中的离体研究表明，GRASE 衍生的 T2 值与标准多回波自旋回波序列获得的值相当，但速度快 6 倍。除此之外，T2 值反映了组织含水量。志愿者的活体测量显示观察者内和观察者间的相关性分别为 R2 = 0.91 和 R2 = 0.94，变异系数分别为 2.4%和 2.2%。虽然整体 T2 时间朝着心底方向显著降低，但无论心肌区域如何，女性志愿者的 T2 时间显著更高。我们发现节段 T2 值与最大收缩期、舒张期应变或心率之间没有相关性。有趣的是，志愿者的年龄与 T2 时间显著相关，而其他同时存在的心血管危险因素则不然。
结论
GRASE 衍生的 T2 图具有高度可重复性。然而，女性以及伴有典型高血压和糖尿病患病率的衰老与心肌 T2 值升高有关。因此，在以诊断方式使用 GRASE 时，必须将性别和年龄视为影响因素。
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