GRE序列在急性颅内出血诊断中的应用研究

目的总结颅内出血在GRE序列上的表现,探讨颅内出血在GRE序列上表现的生物物理学基础。方法CT证实为急性颅内出血的21例患者,其中脑实质内出血9例,蛛网膜下腔出血7例,脑挫裂伤5例。在发病6小时内行常规SE序列的T1WI、T2WI及GRE序列的T2*WI MRI检查,对急性出血的MR征像进行总结分析,并比较常规T2WI及T2*WI对急性出血的诊断价值。结果9例脑实质内出血在常规MR上7例表现为等T1,2例表现为长T1,在T2WI上8例呈不均质的略高信号,1例为等信号,其中有5例在病灶核心区或边缘可见低信号。而在T2*WI上病灶边缘均可见明显的环状低信号或整个病变均呈低信号;7例珠网膜下腔出血中只有3例在常规MR上可见短T1信号,其余4例均正常,而在T2*WI上7例均可见明显的低信号;5例脑挫裂伤表现为不均质的长T1长T2信号,在T2*WI上可见多发的点状低信号。结论GRE序列对颅内出血的敏感性高,诊断准确率明显高于常规的SE序列。临床怀疑颅内出血的患者在进行MR检查时,检查序列应常规包含GRE序列,以进一步提高MRI对其诊断的准确性。

Value of GRE-MRI in the diagnosis of acute intracranial hemorrhage

Objective To explore the appearances of intracranial hemorrhage on GRE-MRI and discuss their biophysical basis.Methods Twenty-one intracranial hemorrhage patients proved by CT were performed conventional SE and GRE MRI examination. Among them, 9 cases were intraparenchymal hemorrhage, 7 were subarachnoid hemorrhage, and 5 were cerebral contusions. The diagnostic accuracy of SE and GRE MRI was analysed. Results Among the 9 intraparenchymal hemorrhage, isointensity was found in 7 on the SE T1WI, and hypointensity was found in 2. On the T2~*WI, inhomogeneous high signal was seen in 8 cases, and low signal area was seen in 5. The remaining one appeared isointensity. Among the 7 subarachnoid hemorrhage, only 3 cases were diagnosed because of the high signal on T1WI. On the T2~*WI, however, obvious low signal was seen in each case. For the 5 contusions, only inhomogeneous low signal on T1WI and high signal on T2WI were seen on conventional SE sequences. On T2~*WI, obvious multiple punctate low signal was seen. Conclusion GRE is very sensitive to intracranial hemorrhage. And itsdiagnostic accuracy is higher than that of SE. When the MRI examination is performed for the patients clinically suspected of intracerebral hemorrhage, the examination protocol should include GRE in order to improve the diagnostic accuracy of MRI.