Nakagawa Daichi, Cushing Cameron, Nagahama Yasunori, Allan Lauren, Hasan David
Department of Neurosurgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA; Department of Biomedical Engineering, Seamans Center for the Engineering Arts and Sciences, University of Iowa, Iowa City, Iowa, USA.
Department of Neurosurgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA.
World Neurosurg. 2017 Jul;103:954.e1-954.e4. doi: 10.1016/j.wneu.2017.04.151. Epub 2017 Apr 30.
Sentinel headache (SH) occurs before aneurysm rupture in an estimated 15%-60% of cases of aneurysmal subarachnoid hemorrhage (aSAH). By definition, noncontrast computed tomography (CT) scan of the brain and lumbar puncture are both negative in patients presenting with SH. One of the theories explaining this phenomenon is that microhemorrhage (MH) from the aneurysm wall contribute to iron deposition in the interface between the aneurysm wall and brain parenchyma. Quantitative susceptibility mapping (QSM) is a recently introduced magnetic resonance imaging (MRI) technique that has proven capable of localizing the deposition of paramagnetic metals, particularly ferric iron. Thus, the QSM sequence may be able to detect iron deposition secondary to MH.
A 76-year-old male presented with the "worst headache of my life." Noncontrast head CT scan and lumbar puncture were negative. Magnetic resonance angiography (MRA) of the brain revealed an anterior communicating artery (A-com) aneurysm measuring 7 mm with a large bleb. T1-weighted imaging (WI), T2-WI, MRA, T2 star-weighted angiography (SWAN), and QSM sequences were obtained. T2-WI, SWAN, and QSM revealed isointense, hypointense, and hyperintense signals, respectively, at the interface of the aneurysm wall and brain tissue. These findings were consistent with deposition of ferric iron at this interface. The A-com aneurysm was treated with coil embolization, and the patient exhibited no postoperative deficits.
The MRI QSM sequence can localize iron deposition resulting from MH within an aneurysmal wall. This sequence may be a promising imaging tool for screening patients presenting with SH.
在约15%-60%的动脉瘤性蛛网膜下腔出血（aSAH）病例中，哨兵头痛（SH）发生在动脉瘤破裂之前。根据定义，出现SH的患者进行的脑部非增强计算机断层扫描（CT）和腰椎穿刺结果均为阴性。解释这一现象的理论之一是，动脉瘤壁的微出血（MH）导致铁在动脉瘤壁与脑实质之间的界面沉积。定量磁化率成像（QSM）是一种最近引入的磁共振成像（MRI）技术，已被证明能够定位顺磁性金属，特别是三价铁的沉积。因此，QSM序列可能能够检测到由MH引起的铁沉积。
一名76岁男性因“我一生中最严重的头痛”就诊。脑部非增强CT扫描和腰椎穿刺结果均为阴性。脑部磁共振血管造影（MRA）显示前交通动脉（A-com）有一个7毫米的动脉瘤，带有一个大的瘤泡。获取了T1加权成像（WI）、T2加权成像、MRA、T2*加权血管造影（SWAN）和QSM序列。T2加权成像、SWAN和QSM分别在动脉瘤壁与脑组织的界面显示等信号、低信号和高信号。这些发现与该界面处三价铁的沉积一致。对A-com动脉瘤进行了弹簧圈栓塞治疗，患者术后无神经功能缺损。
MRI的QSM序列可以定位动脉瘤壁内由MH导致的铁沉积。该序列可能是筛查出现SH患者的一种有前景的成像工具。
