Campbell B G, Zimmerman R D
Department of Radiology, The New York Hospital-Cornell University Medical Center, New York, New York 10021, USA.
Top Magn Reson Imaging. 1998 Aug;9(4):208-27.
We will review the role of magnetic resonance (MR) in assessment of patients with acute neurological abnormalities. The major stumbling block to the use of MR in these patients is the belief that MR is insensitive to hyperacute (<12 h) intracranial hemorrhage and acute subarachnoid hemorrhage (SAH). Hyperacute hemorrhage has characteristic features on MR. Hematomas are iso-to hyperintense on T1-weighted and hyperintense on T2-weighted images. Gradient-echo scans that reveal characteristic peripheral hypointensity are critical to the detection and delineation of hyperacute hematomas. Use of fast fluid-attenuated inversion recovery (FLAIR) sequences has made it possible to detect SAH on MR with a sensitivity that is equal to or greater than computed tomography (CT). SAH produces dramatic hyperintensity in the normally hypointense cerebrospinal fluid on FLAIR. MR has proven useful in the detection of hypertensive encephalopathy and venous thrombosis. These entities can be difficult to diagnose on CT, and in both, early treatment can dramatically improve prognosis. The same is true for acute intracranial infections such as pyogenic abscess, subdural empyema, and herpes simplex encephalitis. MR improves diagnostic accuracy, resulting in more rapid institution of appropriate treatment and improved outcome.
我们将回顾磁共振成像（MR）在评估急性神经功能异常患者中的作用。在这些患者中使用MR的主要障碍是人们认为MR对超急性（<12小时）颅内出血和急性蛛网膜下腔出血（SAH）不敏感。超急性出血在MR上有特征性表现。血肿在T1加权像上呈等信号至高信号，在T2加权像上呈高信号。能显示特征性周边低信号的梯度回波扫描对于超急性血肿的检测和勾画至关重要。快速液体衰减反转恢复（FLAIR）序列的应用使得在MR上检测SAH成为可能，其敏感性等于或高于计算机断层扫描（CT）。SAH在FLAIR上使正常呈低信号的脑脊液产生显著高信号。MR已被证明在检测高血压脑病和静脉血栓形成方面有用。这些疾病在CT上可能难以诊断，而对于这两者，早期治疗都能显著改善预后。急性颅内感染如化脓性脓肿、硬脑膜下积脓和单纯疱疹性脑炎也是如此。MR提高了诊断准确性，从而能更迅速地开始适当治疗并改善预后。
