Radiology department, Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology, Samory Mashela st., 1, Moscow, Russia, 117997.
Philips Healthcare, Moscow, Russia.
Eur Radiol Exp. 2020 Apr 17;4(1):25. doi: 10.1186/s41747-020-00156-3.
Timely diagnosis of cardiac iron overload is important for children with transfusion-dependent anaemias and requires modern measure methods. Nowadays, myocardial iron quantification is performed by magnetic resonance (MR) breath-hold techniques, sensitive to respiratory motion and unfeasible in patients who are unable to hold their breath. Free-breathing T2* mapping sequences would allow to scan children who cannot hold their breath for a specified duration. Our aim was to test a free-breathing T2* mapping sequence, based on motion correction by multiple signal accumulation technique.
We used an electrocardiographically gated T2* mapping sequence based on multiple gradient echo at 3-T in 37 paediatric patients with haematologic disorders aged from 2 to 16. We compared T2* values of myocardium and signal-to-noise ratio of this new sequence with standard breath-holding T2* mapping sequence. T2* values were measured in the interventricular septum for both methods in studies with adequate image quality.
All children were scanned without complications. Five patients were excluded from analysis because of the presence of respiratory artefacts on the T2* images with breath-holding technique due to patient's inability to hold their breath. Breath-holding T2* was 19.5 ± 7.7 ms (mean ± standard deviation), free-breathing T2* was 19.4 ± 7.6 ms, with positive correlation (r = 0.99, R = 0.98; p < 0.001). The free-breathing sequence had a higher signal-to-noise ratio (median 212.8, interquartile range 148.5-566.5) than the breath-holding sequence (112.6, 71.1-334.1) (p = 0.03).
A free-breathing sequence provided accurate measurement of myocardial T2* values in children.
对于依赖输血的贫血症儿童，及时诊断心脏铁过载很重要，这需要采用现代测量方法。目前，心肌铁定量采用磁共振（MR）屏气技术进行，该技术对呼吸运动敏感，对于无法屏气的患者不可行。自由呼吸 T2* 映射序列将允许扫描无法屏气特定时长的儿童。我们的目的是测试一种基于多信号累加技术进行运动校正的自由呼吸 T2* 映射序列。
我们使用基于 3-T 心电门控多梯度回波的 T2* 映射序列，对 37 名年龄 2 至 16 岁的血液系统疾病患儿进行检查。我们比较了新序列和标准屏气 T2* 映射序列的 T2* 值和信噪比。在图像质量足够的研究中，两种方法均测量了室间隔的 T2* 值。
所有患儿均顺利完成扫描，无并发症。由于 5 名患儿因无法屏气而导致屏气 T2* 图像存在呼吸伪影，故被排除在分析之外。屏气 T2* 为 19.5±7.7ms（平均值±标准差），自由呼吸 T2* 为 19.4±7.6ms，两者呈正相关（r=0.99，R=0.98；p<0.001）。自由呼吸序列的信噪比（中位数 212.8，四分位距 148.5-566.5）高于屏气序列（112.6，71.1-334.1）（p=0.03）。
自由呼吸序列可准确测量儿童心肌 T2* 值。
