Computed Tomography Angiography of Carotid Stent. Comparison of Various Self-expandable Stent in a Phantom Model

Carotid computed tomography angiography after cobalt-based alloy carotid artery stenting using ultra-high-resolution computed tomography with model-based iterative reconstruction

In conventional carotid computed tomographic angiography, the artifacts of the stent vary depending on the structure and characteristics of the alloy type. Cobalt-based alloy stents have been reported to exhibit high artifacts, and accurate evaluation of the internal lumen can be difficult. Recently, ultra-high-resolution computed tomography scanner systems have become available for clinical practice. The primary features of this computed tomography scanner are a 0.25-mm detector row width and a 1024 × 1024 matrix. We report a case-series of carotid artery stenting using a cobalt-based alloy stent scanned by an ultra-high-resolution computed tomography scanner system and model-based iterative reconstruction. We also report that the combination of the ultra-high-resolution computed tomography scanner system with model-based iterative reconstruction would be useful to evaluate vessel patency after placement of a cobalt-based alloy stent.

Influence of stenting with open-cell stents vs close-cell stents on the outcomes of patients with bilateral carotid stenosis

BACKGROUND

Carotid artery stenting (CAS) is an effective way to prevent stroke in patients with severe carotid stenosis. However, several studies comparing the outcomes of stenting with open-cell stents (OCS) vs closed-cell stents (CCS) have yielded inconclusive results. This study aimed to compare the outcomes of CAS with OCS vs CCS in the same patients.

METHODS

From year 2000 to 2016, we included 52 patients with severe bilateral carotid stenosis who underwent OCS deployment in one artery and CCS deployment in the contralateral artery. Stents were selected according to arterial anatomy and lesion morphology, and the peri-procedural and long-term outcomes of treatment with OCS vs CCS, were compared in terms of rates of ischemic spot development on early post-procedural diffusion-weighted imaging (ISDWI), in-stent restenosis (ISR), and recurrent stroke.

RESULTS

After stenting with OCS vs CCS, the number (rate) of arteries with no lesion, < 5 lesions, and ≥ 5 lesions on DWI was 9 (32%) vs 8 (27%), 8 (29%) vs 17 (57%), and 11 (39%) vs 5 (17%) (p = .10); number (rate) of arteries with 0%, < 50%, and >50% ISR was 34 (65%) vs 34 (65%), 9 (17%) vs 11 (21%), and 9 (17%) vs 7 (13%) (p = .71); number (rate) of recurrent strokes after CAS was 2 (4%) vs 0 (0%).

CONCLUSION

The rates of peri-procedural cerebral ischemic insult, long-term stent patency, and stroke recurrence indicate that no one carotid stent cell design is superior to the other. We suggest both OCS and CCS are reasonable options for the treatment of severe carotid stenosis.

Application of Time-Resolved 3D Digital Subtraction Angiography to Plan Cerebral Arteriovenous Malformation Radiosurgery

BACKGROUND AND PURPOSE

Time-resolved 3D-DSA (4D-DSA) enables viewing vasculature from any desired angle and time frame. We investigated whether these advantages may facilitate treatment planning and the feasibility of using 4D-DSA as a single imaging technique in AVM/dural arteriovenous fistula radiosurgery.

MATERIALS AND METHODS

Twenty consecutive patients (8 dural arteriovenous fistulas and 12 AVMs; 13 men and 7 women; mean age, 45 years; range, 18-64 years) who were scheduled for gamma knife radiosurgery were recruited (November 2014 to October 2015). An optimal volume of reconstructed time-resolved 3D volumes that defines the AVM nidus/dural arteriovenous fistula was sliced into 2D-CT-like images. The original radiosurgery treatment plan was overlaid retrospectively. The registration errors of stereotactic 4D-DSA were compared with those of integrated stereotactic imaging. AVM/dural arteriovenous fistula volumes were contoured, and disjoint and conjoint components were identified. The Wilcoxon signed rank test and the Wilcoxon rank sum test were adopted to evaluate registration errors and contoured volumes of stereotactic 4D-DSA and integration of stereotactic MR imaging and stereotactic 2D-DSA.

RESULTS

Sixteen of 20 patients were successfully registered in Advanced Leksell GammaPlan Program. The registration error of stereotactic 4D-DSA was smaller than that of integrated stereotactic imaging (P = .0009). The contoured AVM volume of 4D-DSA was smaller than that contoured on the integration of MR imaging and 2D-DSA, while major inconsistencies existed in cases of dural arteriovenous fistula (P = .042 and 0.039, respectively, for measurements conducted by 2 authors).

CONCLUSIONS

Implementation of stereotactic 4D-DSA data for gamma knife radiosurgery for brain AVM/dural arteriovenous fistula is feasible. The ability of 4D-DSA to demonstrate vascular morphology and hemodynamics in 4 dimensions potentially reduces the target volumes of irradiation in vascular radiosurgery.