Department of Radiology, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China.
Siemens Healthcare Ltd, Guangzhou Branch, 510620, China.
Eur J Radiol. 2021 Feb;135:109472. doi: 10.1016/j.ejrad.2020.109472. Epub 2020 Dec 10.
To compare the clinical utility of single-shot echo-planar imaging (SS-EPI) using different breathing schemes and readout-segmented EPI (RS-EPI) in the repeatability of apparent diffusion coefficient (ADC) measurements, signal-to-noise ratio (SNR) and image quality.
In this institutional review board-approved prospective study, hepatic DWIs (b = 50, 300, 600 s/mm) were performed in 22 volunteers on 3.0 T MRI using SS-EPI with free-breathing diffusion-weighted imaging (FB-DWI), breath-hold (BH-DWI), respiratory-triggered (RT-DWI) and navigator-triggered (NT-DWI), and readout-segmented EPI (RS-DWI). ADC and surrogate SNR (sSNR) were measured in nine anatomic locations in the right lobe, and image quality was assessed on all FB-DWI, BH-DWI, RT-DWI, NT-DWI, and RS-DWI sequences. The sequence with the optimal clinical utility was decided by systematically comparing the ADC repeatability, sSNR and image quality of the above DWIs.
In all the five sequences, NT-DWI had the most reliable intra-observer agreement (intraclass correlation coefficient (ICC): 0.900-0.922; all P > 0.05), and a better interobserver agreement (ICC: 0.853-0.960; all p > 0.05) than RS-DWI (ICC:0.881-0.916; some P < 0.05). NT-DWI had the best ADC repeatability in the nine locations (mean ADC absolute differences: 38.47-56.38 × 10 mm/s, limits of agreement (LOA): 17.33-22.52 × 10 mm/s). Also, NT-DWI had the highest sSNR (Reader 1: 50.58 ± 20.11 (Superior), 74.06 ± 28.37 (Central), 80.99 ± 38.11(Inferior)); Reader 2: 48.07 ± 23.92 (Superior), 68.23 ± 32.91 (Central), 76.78 ± 33.07 (Inferior)) in three representative sections except for RS-DWI. Furthermore, NT-DWI had a better image quality than RS-DWI (P < 0.05) and was superior to FB-DWI and BH-DWI in sharpness of the liver (at b = 300 s/mm) (P < 0.05) CONCLUSION: RS-DWI has the best SNR. However, NT-DWI can provide sufficient SNR, excellent image quality, and the best ADC repeatability on 3.0 T MRI. It is thus the recommended sequence for the clinical application of hepatic DWI.
比较单次激发回波平面成像（SS-EPI）使用不同呼吸方案和分段读出 EPI（RS-EPI）在表观扩散系数（ADC）测量的重复性、信噪比（SNR）和图像质量方面的临床实用性。
本研究为机构审查委员会批准的前瞻性研究，在 3.0T MRI 上对 22 名志愿者进行单次激发 EPI 弥散加权成像（SS-EPI），采用自由呼吸弥散加权成像（FB-DWI）、屏气（BH-DWI）、呼吸触发（RT-DWI）和导航触发（NT-DWI）以及分段读出 EPI（RS-DWI）。在右叶的 9 个解剖位置测量 ADC 和替代 SNR（sSNR），并对所有 FB-DWI、BH-DWI、RT-DWI、NT-DWI 和 RS-DWI 序列进行图像质量评估。通过系统比较上述 DWIs 的 ADC 重复性、sSNR 和图像质量，决定具有最佳临床实用性的序列。
在所有 5 种序列中，NT-DWI 具有最可靠的观察者内一致性（组内相关系数（ICC）：0.900-0.922；均 P>0.05），以及优于 RS-DWI 的观察者间一致性（ICC：0.853-0.960；均 P>0.05）。NT-DWI 在 9 个位置的 ADC 重复性最好（平均 ADC 绝对差异：38.47-56.38×10mm/s，一致性限（LOA）：17.33-22.52×10mm/s）。此外，NT-DWI 具有最高的 sSNR（读者 1：50.58±20.11（上部），74.06±28.37（中部），80.99±38.11（下部）；读者 2：48.07±23.92（上部），68.23±32.91（中部），76.78±33.07（下部）），除 RS-DWI 外，在三个代表性切片中均具有最高的 sSNR。此外，NT-DWI 具有比 RS-DWI 更好的图像质量（P<0.05），并且在肝脏清晰度方面优于 FB-DWI 和 BH-DWI（在 b=300s/mm 时）（P<0.05）。
RS-DWI 具有最佳 SNR。然而，NT-DWI 可以在 3.0T MRI 上提供足够的 SNR、出色的图像质量和最佳的 ADC 重复性。因此，它是肝 DWI 临床应用的推荐序列。
