Data acquisition is based on 3D radial sampling, and the arterial spin-labeling technique is used as a preparation pulse for visualization of the blood flow. Silent MRA uses a Silenz pulse sequence (GE Healthcare, Milwaukee, Wisconsin) containing an ultrashort echo time (UTE) combined with arterial spin-labeling. 15 ⇓– 17 Furthermore, it has been reported that gadolinium-based contrast material accumulates in the dentate nucleus and globus pallidus. However, the use of contrast materials in CE-MRA is associated with nephrogenic systemic fibrosis and anaphylactic shock therefore, this technique might not be appropriate for repeated examinations. Therefore, contrast-enhanced MRA (CE-MRA) is used for follow-up after stent-assisted coil embolization. 11 ⇓ ⇓– 14 Although there have been reports of 3D TOF-MRA being used after stent-assisted coil embolization, 12, 13 it remains difficult to visualize flow in an intracranial stent when using this method because of magnetic susceptibility and radiofrequency shielding. On the other hand, 3D TOF-MRA is widely used as a noninvasive substitute for DSA for the follow-up of coiled aneurysms. However, DSA is an invasive technique that carries a risk of neurologic complications, contrast materials, and x-ray radiation. X-ray DSA is the standard technique used for follow-up after an intracranial stent. The use of 2 stents in a “Y” configuration to assist with coil embolization for bifurcation aneurysms has been accepted for broad-neck aneurysms. The 2 stents overlap in the distal BA trunk, with 1 stent penetrating the mesh of the other. 1 ⇓ ⇓ ⇓ ⇓– 6 The Y stent deploys 2 stents from the BA to the bilateral posterior cerebral artery (PCA). The Y-configuration stent-assisted coil embolization technique has been generally used for wide-neck bifurcation aneurysms such as those at the tip of the basilar artery (BA). In recent years, intracranial stents have been used for the treatment of wide-neck aneurysms. ABBREVIATIONS: BA basilar artery CE-MRA contrast-enhanced MRA PCA posterior cerebral artery UTE ultrashort echo time
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