Usefulness of Vessel Wall MR Imaging for Follow-Up after Stent-Assisted Coil Embolization of Intracranial Aneurysms

Abstract

BACKGROUND AND PURPOSE: Follow-up with MRA for intracranial aneurysms after stent-assisted coiling is complicated by imaging artifacts. We evaluated the usefulness of an alternative method: vessel wall MR imaging. MATERIALS AND METHODS: We conducted a single-center, retrospective review of medical records of 47 patients who underwent 3D TOF-MRA, vessel wall MRI, and DSA after stent-assisted coiling between March 2016 and January 2018. We evaluated the mean value of the signal intensity in the stented artery and the contralateral normal artery on vessel wall MRI. The quality of visualization was further compared between TOF-MRA and vessel wall MRI. Furthermore, we evaluated the diagnostic accuracy and concordance rate of TOF-MRA and vessel wall MRI for assessing the patency of the stented parent artery. DSA was used as a reference test. RESULTS: The mean signal intensities of the stented and normal arteries on vessel wall MRI were not significantly different (P ϭ .133). The mean scores for the visualization of the stented parent artery on vessel wall MRI were significantly superior to those of TOF-MRA images (P Ͻ .001). Vessel wall MRI reached an excellent positive predictive value (100%). However, TOF-MRA had a poor positive predictive value (11%; 95% CI, 9%-12%). The likelihood ratios of vessel wall MRI and TOF-MRA were 27.36 (P Ͻ .001) and 2.98 (P ϭ .225), respectively. The concordance rate of vessel wall MRI and TOF-MRA with DSA for evaluating the state of the stented artery was 100% (ϭ 1) and 28% (ϭ 0.038), respectively. CONCLUSIONS: Vessel wall MRI may be useful in evaluating the patency of stented arteries after stent-assisted coil embolization for intracranial aneurysms.

Vessel wall imaging with advanced flow suppression in the characterization of intracranial aneurysms following flow diversion with Pipeline embolization device

“…Specifically in the case of aneurysms, emerging interest in VWI as a biomarker of aneurysm wall integrity has supported its use to identify aneurysms at high risk of rupture, to surveil aneurysms, or to remove uncertainty about the source of hemorrhage and to identify culprit aneurysms preoperatively 2 3. VWI is particularly well suited to longitudinal characterization in light of its non-invasive nature, potentially obviating the need for invasive catheter angiographic monitoring; however, past studies have focused primarily on the characterization of treatment-naïve, unruptured, and ruptured aneurysms while its usefulness for treated aneurysms remains mostly unexplored or restricted to limited series 4–7. We recently have implemented a custom-optimized black-blood VWI for characterization of treated aneurysms, with particular attention paid to the imaging evolution of aneurysms following flow diversion, now widely considered as the first-line treatment for aneurysms of varying subtypes.…”

Usefulness of black-blood magnetic resonance angiography generated from vessel wall imaging after the stent-assisted treatment of intracranial arterial diseases

“…For 3D-TOF MRA, shielding artifacts reportedly have a larger effect on the signal of the stented artery than susceptibility artifacts. 16 However, since a previous study of VWI using the same method as that used in the present study reported that an in-stent thrombus could be visualized, 14 we consider that our BB-MRA findings generated from VWI correspond to the black-blood imaging of blood flow, and not a loss in signal arising from RF shielding artifacts. Additionally, our literature search revealed no reports on RF shielding artifacts in VWI data.…”

“…However, our study did not include these cases. Kim et al 14 reported that an in-stent thrombus could be visualized using VWI. Therefore, we consider that our study of BB-MRA generated VWI would have been more convincing with the addition of cases of instent stenosis and thrombosis.…”

“… 12 , 13 A previous study of VWI using the same method reported that an in-stent thrombus could be visualized. 14 However, there is no report of quantitative evaluation of the accuracy of stented arteries between 3D-TOF MRA and VWI. Therefore, in the present study, we compared the depiction of stented arteries between black-blood MRA (BB-MRA) generated from VWI data obtained using the SPACE sequence and conventional 3D-TOF MRA as well as DSA.…”

Usefulness of 3D T1-SPACE in Combination With 3D-TOF MRA for Follow-Up Evaluation of Intracranial Aneurysms Treated With Pipeline Embolization Devices

“…This may be an effective non-invasive imaging method for assessing the risk of aneurysm rupture. Black blood MR imaging can clearly display the vascular wall as low signals by reducing the blood flow effect (27). Compared to HR-MRI technology that had limited scanning ranges and long image acquisition times, 3D T1-SPACE uses isotropic volume scanning for 3D high-resolution reconstruction at any level.…”