Magnetic resonance imaging with even-echo rephasing sequences in the assessment and management of giant intracranial aneurysms.

The role of magnetic resonance imaging in the assessment of giant intracranial aneurysms was compared with angiography and contrast-enhanced computed tomography (CT) in 18 patients. The use of T1- and T2-weighted spin-echo (SE) sequences demonstrated both the presence and the evolution of thrombus within these lesions. High-velocity flow within the parent vessels and still-patent lumen could be defined as an area of absent signal. The use of even-echo rephasing (EER) sequences provided a rapid technique for demonstrating and confirming the presence of luminal flow, which is shown as areas of high signal. The combination of SE and EER techniques proved superior to CT in the assessment of thrombus and flow patterns in these lesions, as well as enabling superior demonstration of the patency of the parent vessel following surgical ligation. Computed tomography remains the most accurate method of defining the presence and location of associated calcification.