Aneurysm wall enhancement on magnetic resonance imaging as a risk factor for progression of unruptured vertebrobasilar dissecting aneurysms after reconstructive endovascular treatment

J Neurosurg 128:747–755, 2018

The recurrence rate of vertebrobasilar dissecting aneurysms (VBDAs) after reconstructive endovascular treatment (EVT) is relatively high. The aneurysm wall enhancement on high-resolution MRI (HRMRI) reportedly predicts an unsteady state of an intracranial aneurysm. The authors used HRMRI to investigate the relationship between wall enhancement on HRMRI and progression of VBDAs after reconstructive EVT.

METHODS From January 2012 to December 2015, patients with an unruptured VBDA who underwent reconstructive EVT were enrolled in this study. Preoperative enhanced HRMRI was performed to evaluate radiological characteristics. The relationships between aneurysm wall enhancement and various potential risk factors were statistically analyzed. Follow-up angiographic examination was performed with digital subtraction angiography and conventional HRMRI. Cox regression analysis was performed to identify predictors of VBDA progression after reconstructive EVT.

RESULTS Eighty-two patients (12 women and 70 men, mean age 53.48 ± 9.23 years) with 83 VBDAs were evaluated in the current study. The average maximum diameter of the VBDAs was 11.30 ± 7.90 mm. Wall enhancement occurred in 43 VBDAs (51.81%). Among all 83 VBDAs, 62 (74.70%) were treated by stent-assisted coil embolization and 21 (25.30%) by stenting alone. The mean duration of imaging follow-up among all 82 patients was 10.55 months (range 6–45 months), and 15 aneurysms (18.07%) exhibited progression. The statistical analysis indicated no significant differences in age, sex, risk factors (high blood pressure, smoking, diabetes mellitus, and a high cholesterol level), VBDA stage, or VBDA size between enhanced and unenhanced VBDAs. Univariate Cox regression analysis showed that both the maximum diameter of the VBDAs and wall enhancement were associated with recurrence (p < 0.05). Multivariate Cox proportional hazard regression analysis showed that the maximum diameter of the VBDAs and wall enhancement on HRMRI were independent risk factors for aneurysm progression (p < 0.05).

CONCLUSIONS Aneurysm size and wall enhancement on HRMRI can predict the progression of VBDAs after reconstructive EVT.

Partially thrombosed intracranial aneurysms: symptoms, evolution, and therapeutic management

Acta Neurochir (2010) 152:2133–2142. DOI 10.1007/s00701-010-0772-9

Partially thrombosed intracranial aneurysms (PTIAs) are different from saccular or nonthrombosed giant or large aneurysms, as they are characterized by multiple intramural thrombotic phenomena related to recurrent vessel wall dissections.

Methods We retrospectively reviewed clinical and radiological files of 23 consecutive patients with PTIAs (mean age 49.3 years). Twenty-two lesions were studied by magnetic resonance imaging (MRI). Patients were managed by endovascular treatments, medically with steroids, or conservatively.

Results Thirteen patients presented with progressive neurological symptoms. Subarachnoid hemorrhage was suspected but not proven in three. At MRI, 90.9% of PTIAs caused mass effect; perilesional T2 hypersignal compatible with edema was evident in 13.6%. Aneurysmal wall enhancement was detectable in 63.2% of the PTIAs and considered a marker of inflammatory processes. Parent artery occlusion was performed in seven patients with clinical improvement in six. Selective coiling was proposed in three patients (one improved, one remained stable, and one experienced symptoms progression). Three patients were treated with steroids and improved. Ten patients were managed conservatively: eight because spontaneous thrombosis of the lesion had been diagnosed and two because of clinical and radiological stability.

Conclusions The natural history of PTIAs is different from other aneurysms. They most commonly present with progressive neurological symptoms due to mass effect. MRI properly diagnoses PTIAs and allows precise followup, more accurately than angiography because it detects prominent “abluminal” features indicating inflammation and neovascularization. Spontaneous thrombosis is part of the natural history of PTIAs and it should be taken in consideration when discussing the therapeutic management.