AJNR SILENZ PULSE SEQQUENCE FULL

The average interval between the aneurysm treatment and both MRAs was 187.9 days (range, 1вЂ“395 days). The average interval between the latest DSA and both MRAs was 27 days (range, 1вЂ“180 days). All patients had incidentally found unruptured aneurysms and were followed-up with silent MRA, 3D TOF-MRA, and DSA. Written informed consent was not required because of the retrospective nature of this study.

Therefore, in the present study, we evaluated the usefulness of silent MRA compared with 3D TOF-MRA for follow-up after Y-configuration stent-assisted coil embolization for basilar tip aneurysms.Д«etween October 2014 and September 2015, 7 aneurysm cases treated with Y-configuration stent-assisted coil embolization were retrospectively examined. To the best of our knowledge, there have been no studies of the use of nonвЂ“contrast-enhanced MRA for follow-up after Y-configuration stent-assisted coil embolization for basilar tip aneurysms. Thus, silent MRA can evaluate the blood flow in an intracranial stent. UTE of silent MRA minimizes phase dispersion of the labeled blood flow signal and decreases magnetic susceptibility to coils and stents. 19, 20 It is a nonвЂ“contrast-enhanced MRA technique therefore, it is better for the patient and suitable for repeated follow-ups. 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 в‡“вЂ“ 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 в‡“ в‡“вЂ“ 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 вЂњYвЂќ 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 в‡“ в‡“ в‡“ в‡“вЂ“ 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. This method can achieve selective fat suppression and enhancement in IR imaging.ABBREVIATIONS: BA basilar artery CE-MRA contrast-enhanced MRA PCA posterior cerebral artery UTE ultrashort echo time The noise level of synthetic signals was generally no more than twice that of direct acquisition signals, as predicted.

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Synthetic IR signals of the brain parenchyma consistently matched directly acquired signals to within 6%, with respect to the full magnetization signal. Other combinations of pulse sequences were also studied, and synthetic images were compared visually and quantitatively to directly acquired images with corresponding parameters. MSE data acquired in a time equivalent to a TR of 2,000 msec can be used to generate inversion-recovery (IR) images for arbitrarily chosen TI inversion times. A new method-'pulse sequence extrapolation' -synthesizes images for pulse sequences different from that of the acquisition. Previous reports have presented validation studies of magnetic resonance (MR) image synthesis in which multiple spin-echo (MSE) source data were used to generate spin-echo images for various echo times and repetition times (TRs).

Ajnr silenz pulse seqquence