High-Degree Middle Cerebral Artery Stenosis : Can Advanced 3D DSA-MRI Fusion Imaging Better Illustrate Plaques and Perforators?

Visualization of Culprit Perforating Artery in Subcortical Infarction Using 3D MRI and Angiography Fusion Image

PURPOSE

Visualizing the culprit perforating artery in subcortical infarction using in vivo imaging is challenging. We aimed to identify the culprit perforating arteries in subcortical infarctions and assess their morphology using an image fusion technique.

METHODS

We retrospectively reviewed consecutive patients who had an ischemic stroke in the anterior circulation perforating area (caudate nucleus, lentiform nucleus, internal capsule, corona radiata, or centrum semiovale) and underwent three-dimensional rotational-angiography (3D-RA) and 3D fluid-attenuated inversion recovery MRI. Images were registered using an original fusion software. The spatial relationship between the infarction and culprit perforating artery and its morphological characteristics were analyzed in the fusion images. Stenosis was defined as > 50% luminal narrowing or a focal intraluminal defect in the perforating artery.

RESULTS

Of 118 patients, the culprit perforating artery was identified in 52 patients (44%); They tended to have younger age and had a higher baseline NIHSS score and higher prevalence of infarcts in the lentiform nucleus than did those without identified culprit perforating artery. Among the 44 patients with assessable morphology of the culprit perforating artery, 27 (61%) exhibited stenosis in the proximal segment. Atrial fibrillation was more frequent in patients without stenosis in the proximal segment of the culprit perforating artery than in those with stenosis (29% vs. 4%, P = 0.03).

CONCLUSION

The 3D-RA and MRI fusion technique enables identification of the culprit perforating arteries in subcortical infarctions, especially in the lentiform nucleus. Morphological features of the culprit perforating artery may be associated with the etiological mechanism of stroke.

Intracranial stenting with the Neuroform Atlas Stent for symptomatic intracranial atherosclerotic stenosis: a bi-center retrospective analysis including stroke recurrence nomogram

Background

Intracranial stenting with the Neuroform Atlas Stent is an emerging option for patients with symptomatic intracranial atherosclerotic stenosis (sICAS) who do not respond to intensive medical treatment. However, the efficacy, safety, and risk factors associated with postoperative stroke recurrence remain controversial.

Methods

A total of 326 consecutive patients with sICAS treated with intracranial stenting using the Neuroform Atlas Stent were retrospectively analyzed to evaluate the efficacy and safety of the procedure. Patients were randomly assigned to a training set and a validation set in a 7:3 ratio. Significant variables in the univariate logistic analyses were included in the final multivariate logistic regression analyses in the training set. Subsequently, we developed a predictive nomogram for sICAS treated with a Neuroform Atlas Stent to predict the likelihood of stroke recurrence at 6 months.

Results

The overall mean stenosis rate of the target artery was 88.85% ± 6.53% before the stenting (T0), 47.58% ± 9.94% at the end of the procedure (T1), and 40.21% ± 7.77% at the 6-month follow-up (T2). The stenosis rate was statistically significant between T0 and T1 (p < 0.01) and between T0 and T2 (p < 0.01). At 6 months postoperatively, 36 patients had a stroke recurrence linked to the target artery. Diabetes, acute ischemic stroke (AIS), plaque burden on vessel wall MRI, enhancement ratio on vessel wall MRI, and stenosis (T1) were independent predictors of stroke recurrence. A predictive nomogram was developed, showing strong predictive capability with the area under the curve of 0.933 for the training set and 0.949 for the validation set.

Conclusion

Intracranial stenting with the Neuroform Atlas Stent is a potentially safe and effective treatment for sICAS. Risk factors for recurrent stroke post-procedure include diabetes, current smoker, current drinker, AIS, plaque burden, enhancement ratio, and stenosis (T1).

Benefit of Advanced 3D DSA and MRI/CT Fusion in Neurovascular Pathology

Digital subtraction angiography provides excellent spatial and temporal resolution; however, it lacks the capability to depict the nonvascular anatomy of the brain and spinal cord.A review of the institutional database identified five patients in whom a new integrated fusion workflow of cross-sectional imaging and 3D rotational angiography (3DRA) provided important diagnostic information and assisted in treatment planning. These included two acutely ruptured brain arteriovenous malformations (AVM), a small superficial brainstem AVM after radiosurgery, a thalamic microaneurysm, and a spine AVM, and fusion was crucial for diagnosis and influenced further treatment.Fusion of 3DRA and cross-sectional imaging may help to gain a deeper understanding of neurovascular diseases. This is advantageous for planning and providing treatment and, most importantly, may harbor the potential to minimize complication rates. Integrating image fusion in the work-up of cerebrovascular diseases is likely to have a major impact on the neurovascular field in the future.

Sub-satisfactory recanalization of severe middle cerebral artery stenoses can significantly improve hemodynamics

Purpose

To investigate the effect of sub-satisfactory stent recanalization on hemodynamic stresses for severe stenoses of the middle cerebral artery (MCA) M 1 segment.

Materials and methods

Patients with severe stenoses of the MCA M1 segment treated with endovascular stent angioplasty were retrospectively enrolled. Three-dimensional digital subtraction angiography before and after stenting was performed; the computational fluid dynamics (CFD) analysis of hemodynamic stresses at the stenosis and normal segments proximal and distal to the stenoses was analyzed.

Results

Fifty-one patients with severe stenosis at the MCA M1 segment were enrolled, with the stenosis length ranging from 5.1 to 12.8 mm (mean 9 ± 3.3 mm). Stent angioplasty was successful in all (100%) the patients. The angiography immediately after stenting demonstrated a significant (P &lt; 0.05) decrease in MCA stenosis after comparison with before stenting (31.4 ±12.5% vs. 87.5 ± 9.6%), with residual stenosis of 15–30% (mean 22.4 ± 3.5%). Before stenting, the total pressure was significantly higher (P &lt; 0.0001), while the WSS, velocity, and vorticity were all significantly decreased (P &lt; 0.0001) at the normal arterial segment proximal to the stenosis, and the total pressure, WSS, velocity, and vorticity were all significantly decreased (P &lt; 0.0001) at the normal arterial segment distal to the stenosis compared with those at the stenosis. After sub-satisfactory stenting recanalization, all the hemodynamic stresses proximal or distal to the stenosis and at the perforator root were improved compared with those before stenting and were similar to those after virtual stenosis removal.

Conclusion

Sub-satisfactory recanalization of severe MCA stenoses can significantly improve the hemodynamic status for cerebral perfusion at the stenoses.

Plaque morphology in acute symptomatic intracranial atherosclerotic disease

BACKGROUND

Intracranial atherosclerotic disease (ICAD) is globally a major ischaemic stroke subtype with high recurrence. Understanding the morphology of symptomatic ICAD plaques, largely unknown by far, may help identify vulnerable lesions prone to relapse.

METHODS

We prospectively recruited patients with acute ischaemic stroke or transient ischaemic attack attributed to high-grade ICAD (60%-99% stenosis). Plaque morphological parameters were assessed in three-dimensional rotational angiography, including surface contour, luminal stenosis, plaque length/thickness, upstream shoulder angulation, axial/longitudinal plaque distribution and presence of adjoining branch atheromatous disease (BAD). We compared morphological features of smooth, irregular and ulcerative plaques and correlated them with cerebral ischaemic lesion load downstream in MRI.

RESULTS

Among 180 recruited patients (median age=60 years; 63.3% male; median stenosis=75%), plaque contour was smooth (51 (28.3%)), irregular (101 (56.1%)) or ulcerative (28 (15.6%)). Surface ulcers were mostly at proximal (46.4%) and middle one-third (35.7%) of the lesions. Most (84.4%) plaques were eccentric, and half had their maximum thickness over the distal end. Ulcerative lesions were thicker (medians 1.6 vs 1.3 mm; p=0.003), had steeper upstream shoulder angulation (56.2° vs 31.0°; p<0.001) and more adjoining BAD (83.3% vs 57.0%; p=0.033) than non-ulcerative plaques. Ulcerative plaques were significantly associated with coexisting acute and chronic infarcts downstream (35.7% vs 12.5%; adjusted OR 4.29, 95% CI 1.65 to 11.14, p=0.003). Sensitivity analyses in patients with anterior-circulation ICAD lesions showed similar results in the associations between the plaque types and infarct load.

CONCLUSIONS

Ulcerative intracranial atherosclerotic plaques were associated with vulnerable morphological features and had a higher cumulative infarct load downstream.