Correlation of Inflow Velocity Ratio Detected by Phase Contrast Magnetic Resonance Angiography with the Bleb Color of Unruptured Intracranial Aneurysms

Intracranial aneurysm stiffness assessment using 4D Flow MRI

BACKGROUND

Although arterial stiffness is known as a biomarker for cardiovascular events and stroke, there is limited information in the literature regarding the stiffness of intracranial aneurysms. In this study, we aim to assess the stiffness of intracranial aneurysms using 4D Flow MRI.

METHODS

A total of 27 aneurysms in 25 patients with internal carotid artery aneurysms were included in this study. Using 4D Flow MRI, we measured the arterial pulse wave form during a cardiac cycle at planes proximal and distal to the target aneurysm. The damping of these waveforms through the aneurysm was defined as the aneurysm damping index (ADI) and compared to the contralateral side. We also investigated the clinical factors related to the ADI.

RESULTS

ADI assessment was successful in all cases. The average ADI was 1.18±0.28, which was significantly larger than 1.0 (P = 0.0027 [t-test]). The ADI on the aneurysm side was larger than on the contralateral side (1.19±0.30 vs 1.05±0.17, P = 0.029 [t-test]). On multivariate analysis, the use of beta-blockers (β=0.46, P = 0.015) and smoking history (β=-0.22, P = 0.024) showed a significant correlation with ADI.

CONCLUSION

We have proposed a novel method to observe arterial pulse wave dumping through intracranial aneurysm using 4D Flow MRI. The damping can be quantitatively observed, and the ADI has correlations with clinical factors such as antihypertensive drugs and smoking. Further studies should focus more on evaluating aneurysm stiffness and its clinical applications.

"Cutoff Clipping" Technique as a Tentative Clipping Alternative for Large Aneurysms: A Preliminary Study

BACKGROUND

Intraoperative rupture of an aneurysm is potentially devastating. The thin-walled regions (TIWRs) of an aneurysm are associated with rupture risk. This study aimed to describe the feasibility and concerns of the "cutoff clipping" technique for TIWRs disposition of certain complex aneurysms.

METHODS

Three cases were reported to illustrate the "cutoff clipping" technique which was applied to clip a large aneurysm. This study emphasized the exposure and clipping of the aneurysm fundus. The fundus was dissected according to the TIWRs size threshold the author proposed and was clipped transversely by a temporary clip to achieve size reduction and blood flow disconnection. The authors called this the "cutoff clipping" technique. After the cutoff clip was placed, the neck of the aneurysm was further dissected and clipped.

RESULTS

After successfully placing the cutoff clip, the surgeon achieved to reduce the size of the fundus, decrease the TIWRs proportion, and disconnect the blood flow from the neck to the distal thin-walled dome. Sequentially, three aneurysms were clip-ligated without complications.

CONCLUSION

The "cutoff clipping" technique applied under suitable conditions is a potential choice to dissect and clip a complex aneurysm with an adhesive neck and thin-walled dome.