Zhongbin Tian

Bifurcation Type and Larger Low Shear Area Are Associated with Rupture Status of Very Small Intracranial Aneurysms

Background Characterization of the risk factors for rupture of very small intracranial aneurysm (VSIA, ≤3 mm) is clinically valuable, since VSIAs are implicated in subarachnoid hemorrhage. The aim of this study was to identify morphological and hemodynamic parameters that independently characterize the rupture status of VSIAs. Methods We conducted a retrospective study of consecutive VSIAs between September 2010 and February 2014 in our institute. A series of morphologic and hemodynamic parameters were evaluated using computational fluid dynamics, based on patient-specific three-dimensional geometrical models. Results We identified 186 patients with 206 VSIAs (73 ruptured, 133 unruptured). Univariable logistic regression analysis showed that bifurcation type, parent artery diameter, size ratio, time-averaged wall shear stress (WSS), maximum WSS, minimum WSS, and low shear area (LSA) were related to rupture status. Bifurcation type and larger LSA were independently associated with rupture status in multivariable logistic regression (p = 0.002 and p = 0.003, respectively). Conclusion Bifurcation type and larger LSA were independently associated with VSIA rupture status. Further studies are needed prospectively on patient-derived geometries prior to rupturing based on large multi-population data to confirm the present findings.

Rupture Risk Assessment for Mirror Aneurysms with Different Outcomes in the Same Patient.

Background The purpose of this research was to analyze the effect of morphologic and hemodynamic characteristics on mirror aneurysms in which one ruptured and the other did not, within the same patient, and to identify reliable predictors of rupture. Methods We performed three-dimensional angiographic imaging in 56 patients with intracranial mirror aneurysms for computational fluid dynamic studies from January 2009 to December 2015. The ruptured aneurysm simulations were conducted with geometry obtained after rupture. The significance of morphologic and hemodynamic parameters with respect to rupture was analyzed. Multivariate logistic regression analysis was applied to significant parameters to identify independent discriminators. Results Three morphologic factors (aneurysm size, aspect ratio, and size ratio) and two hemodynamic factors [time-averaged mean wall shear stress (WSS) and low WSS area] were statistically associated with aneurysm rupture (p < 0.05). On multivariate logistic regression, a larger size (OR 2.572, p = 0.001) and lower WSS (OR 0.609, p = 0.045) were independent significant factors for rupture. Conclusion Larger aneurysm size and lower WSS were independently associated with the rupture status of aneurysms. These findings need to be confirmed by large multicenter and multi-population studies.

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

OBJECTIVE 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.

Treatment for Spontaneous Intracranial Dissecting Aneurysms in Childhood: A Retrospective Study of 26 Cases

Objective This study aimed to assess the clinicoradiological features and treatment outcomes of intracranial dissecting aneurysms (IDAs) in childhood. Methods We conducted a retrospective study of pediatric patients who were treated for spontaneous IDAs in our institute between January 2010 and December 2015. The clinical presentation, aneurysm characteristics, treatment modality, and outcome were studied. Results We studied 26 pediatric patients (mean age, 13.4 years; range, 4–18 years) with 31 IDAs who comprised 6.9% of all IDA patients treated during the same period. Seventeen (65.4%) patients were males, and nine (34.6%) were females. The incidence of large (≥10 mm in size) or giant aneurysms (≥25 mm in size) was 65.5%. Twenty-one (80.8%) patients underwent endovascular or surgical treatment and five (19.2%) received conservative treatment. Perioperative complications occurred in three patients, in whom two eventually recovered completely with a Glasgow Outcome Scale (GOS) score of 5 and one partially recovered with a GOS score 4. Overall, 25 (96.2%) patients had a favorable outcome and one (3.8%) had an unfavorable outcome at a mean follow-up of 22.8 months (range, 6–60 months). Conclusion Pediatric IDAs are rare. In this series, endovascular management was a relatively safe and effective method of treatment for pediatric IDAs. However, continued follow-up is required because of the possibility of aneurysm recurrence and de novo aneurysm formation after treatment.

Efficient simulation of a low-profile visualized intraluminal support device: a novel fast virtual stenting technique

BackgroundThe low-profile visualized intraluminal support (LVIS) stent has become a promising endovascular option for treating intracranial aneurysms. To achieve better treatment of aneurysms using LVIS, we developed a fast virtual stenting technique for use with LVIS (F-LVIS) to evaluate hemodynamic changes in the aneurysm and validate its reliability.MethodsA patient-specific aneurysm was selected for making comparisons between the real LVIS (R-LVIS) and the F-LVIS. To perform R-LVIS stenting, a hollow phantom based on a patient-specific aneurysm was fabricated using a three-dimensional printer. An R-LVIS was released in the phantom according to standard procedure. F-LVIS was then applied successfully in this aneurysm model. The computational fluid dynamics (CFD) values were calculated for both the F-LVIS and R-LVIS models. Qualitative and quantitative comparisons of the two models focused on hemodynamic parameters.ResultsThe hemodynamic characteristics for R-LVIS and F-LVIS were well matched. Representative contours of velocities and wall shear stress (WSS) were consistently similar in both distribution and magnitude. The velocity vectors also showed high similarity, although the R-LVIS model showed faster and more fluid streams entering the aneurysm. Variation tendencies of the velocity in the aneurysm and the WSS on the aneurysm wall were also similar in the two models, with no statistically significant differences in either velocity or WSS.ConclusionsThe results of the computational hemodynamics indicate that F-LVIS is suitable for evaluating hemodynamic factors. This novel F-LVIS is considered efficient, practical, and effective.

Risk Factors of Recurrence after Stent(s)-Assisted Coiling of Intracranial Vertebrobasilar Dissecting Aneurysms: A Multicenter Study

Background We aimed to evaluate the risk factors of recurrence after stent(s)-assisted coiling (SAC) of intracranial vertebrobasilar dissecting aneurysms (VBDAs) based on 168 consecutive patients. Methods Between January 2011 and December 2015, 168 consecutive patients with 170 intracranial VBDAs, which were treated by SAC, were recruited from four high-volume centers. We used multivariate logistic regression to examine factors that affected recurrence of VBDAs. Results The mean duration of clinical follow-up of the 168 patients was 7.81 months (range, 3–24 months). Of the 168 patients, 4 (2.38%) suffered from intraoperative complications and 16 (9.52%) had postoperative complications. Two (1.19%) had severe disability. Imaging follow-up was available for 168 patients (170 VBDAs), with a mean duration 7.81 months, and 24 (14.12%) cases of recurrence of aneurysms were noted. Aneurysm size and metal coverage of stent(s) at the neck were independent predictors of recurrence after SAC by logistic regression analysis. Conclusion This multicenter cohort study shows that aneurysm size and the metal coverage of stent(s) at aneurysmal neck are independent factors associated with recurrence of VBDAs after SAC.