Fondazione G.Monasterio CNR-Regione Toscana and Institute of Clinical Physiology, Pisa, Italy.
J Magn Reson Imaging. 2011 Feb;33(2):348-55. doi: 10.1002/jmri.22417.
To evaluate the effectiveness of the single ROI approach for the detection of hepatic iron burden in thalassemia major (TM) patients in respect to a whole liver measurement.
Five transverse hepatic slices were acquired by a T2* gradient-echo sequence in 101 TM patients and 20 healthy subjects. The T2* value was calculated in a single region of interest (ROI) defined in the medium-hepatic slice. Moreover, the T2* value was extracted on each of the eight ROIs defined in the functionally independent segments. The mean hepatic T2* value was calculated.
For patients, the mean T2* values over segments VII and VIII were significantly lower. This pattern was substantially preserved in the two groups identified considering the T2* normal cutoff. All segmental T2* values were correlated with the single ROI T2* value. After the application of a correction map based on T2* fluctuations in the healthy subjects, no significant differences were found in the segmental T2* values.
Hepatic T2* variations are low and due to artifacts and measurement variability. The single ROI approach can be adopted in the clinical arena, taking care to avoid the susceptibility artifacts, occurring mainly in segments VII and VIII.
评估单 ROI 方法在检测地中海贫血症 (TM) 患者肝脏铁负荷方面的有效性，与全肝测量相比。
通过 T2梯度回波序列在 101 例 TM 患者和 20 例健康受试者中获得 5 个肝的横断位切片。在中肝切片中定义一个 ROI 来计算 T2值。此外，在功能独立的 8 个 ROI 中提取每个 ROI 的 T2值。计算平均肝 T2值。
对于患者，VII 段和 VIII 段的平均 T2值明显较低。这种模式在考虑 T2正常截止值的两组中基本保持不变。所有节段 T2值与单 ROI T2值相关。在应用基于健康受试者 T2波动的校正图后，节段 T2值没有发现显著差异。
肝脏 T2*的变化很小，主要是由于伪影和测量的可变性。在临床实践中可以采用单 ROI 方法，但要注意避免主要发生在 VII 段和 VIII 段的磁敏感伪影。
