Imaging and Management in Subarachnoid Hemorrhage

The consequences of a subarachnoid hemorrhage (SAH) have a highly variable but often major impact on the individual patient but also on socioeconomics, due to the high case fatality and morbidity. Making a swift and correct diagnosis is of utmost importance, as a delay and misdiagnosis of an aneurysmal cause of SAH can detrimentally influence the outcome. Clinical neuroradiology plays a crucial role in diagnosis and treatment of SAH.The initial workup of all good- and poor-grade SAH patients is based on noninvasive neuroradiological techniques to localize the aneurysm after which swift treatment should be executed to secure the aneurysm and prevent re-bleeding. In situations where no definitive diagnosis is possible, additional digital subtraction (catheter) angiography is required to depict an aneurysmal cause and to rule out other possible causes of SAH. The distribution of blood in the subarachnoid space plays an important role in determining whether or not to proceed with additional imaging. In patients with a clear perimesencephalic distribution, and a normal CT angiography, no additional or repeat imaging is required.The endovascular and surgical management of ruptured aneurysms should be regarded complementary, with a preference for endovascular treatment. Local cerebrovascular anatomic variations should be taken in account. Hydrocephalus and delayed cerebral ischemia (DCI) are the most frequent SAH-related complications in the first 2 weeks after SAH. Imaging of DCI with the latest CT and MR perfusion techniques can support the clinical diagnosis and improve the management. Follow-up imaging after treatment is important not only to confirm the stability of aneurysm occlusion, especially after coiling, but also to define the presence and development of additional aneurysms, even many years after the initial SAH.