A Multicenter Pilot Study on the Clinical Utility of Computational Modeling for Flow-Diverter Treatment Planning.

BACKGROUND AND PURPOSE: Selection of the correct flow-diverter size is critical for cerebral aneurysm treatment success, but it remains challenging due to the interplay of device size, anatomy, and deployment. Current convention does not address these challenges well. The goals of this pilot study were to determine whether computational modeling improves flow-diverter sizing over current convention and to validate simulated deployments. MATERIALS AND METHODS: Seven experienced neurosurgeons and interventional neuroradiologists used computational modeling to prospectively plan 19 clinical interventions. In each patient case, physicians simulated 2-4 flow-diverter sizes that were under consideration based on preprocedural imaging. In addition, physicians identified a preferred device size using the current convention. A questionnaire on the impact of computational modeling on the procedure was completed immediately after treatment. Rotational angiography image data were acquired after treatment and compared with flow-diverter simulations to validate the output of the software platform. RESULTS: According to questionnaire responses, physicians found the simulations useful for treatment planning, and they increased their confidence in device selection in 94.7% of cases. After viewing the simulations results, physicians selected a device size that was different from the original conventionally planned device size in 63.2% of cases. The average absolute difference between clinical and simulated flow-diverter lengths was 2.1 mm. In 57% of cases, average simulated flow-diverter diameters were within the measurement uncertainty of clinical flow-diverter diameters. CONCLUSIONS: Physicians found computational modeling to be an impactful and useful tool for flow-diverter treatment planning. Validation results showed good agreement between simulated and clinical flow-diverter diameters and lengths.

Interobserver variability in retreatment decisions of recurrent and residual aneurysms.

BACKGROUND AND PURPOSE: The degree of variation in retreatment decisions for residual or recurrent aneurysms among endovascular therapists remains poorly defined. We performed a multireader study to determine what reader and patient variables contribute to this variation. MATERIALS AND METHODS: Seven endovascular therapists (4 neuroradiologists, 3 neurosurgeons) independently reviewed 66 cases of patients treated with endovascular coil embolization for ruptured or unruptured aneurysm. Cases were rated on a 5-point scale recommending for whether to retreat and a recommended retreatment type. Reader agreement was assessed by intraclass correlation coefficient and by identifying cases with a "clinically meaningful difference" (a difference in score that would result in a difference in treatment). Variables that affect reader agreement and retreatment decisions were examined by using the Wilcoxon signed-rank test, Pearson χ(2) test, and linear regression. RESULTS: Overall interobserver variability for decision to retreat was moderate (ICC = 0.50; 95% CI, 0.40-0.61). Clinically meaningful differences between at least 2 readers were present in 61% of cases and were significantly more common among neuroradiologists than neurosurgeons (P = .0007). Neurosurgeons were more likely to recommend "definitely retreat" than neuroradiologists (P < .0001). Previously ruptured aneurysms, larger remnant size, and younger patients were associated with more retreat recommendations. Interobserver variability regarding retreatment type was fair overall 0.25 (95% CI, 0.14-0.41) but poor for experienced readers 0.14 (95% CI, 0-0.34). CONCLUSIONS: There is a large amount of interobserver variability regarding the decision to retreat an aneurysm and the type of retreatment. This variability must be reduced to increase consistency in these subjective outcome measurements.

Spontaneous disappearance of vein of galen malformation and posterior fossa venous pouch.

Cerebrovascular anomalies remain an issue of controversy regarding diagnosis, classification, and treatment. We report the first case of total and asymptomatic regression and disappearance of a vein of Galen malformation associated with a posterior fossa venous pouch. Different aspects of the vein of Galen are discussed together with emphasis on the underlying mechanisms of spontaneous thrombosis and regression.A 4-month-old boy presented with macrocrania and signs of intracranial hypertension. Computerized tomography disclosed two masses, the first was a giant aneurysmal dilatation in the posterior fossa, and the second was a gigantic pouch at the level of the vein of Galen. Hydrocephalus was treated by ventriculo-peritoneal shunting. Two months later, the shunt was revised, and posterior fossa was explored without active treatment. Both abnormalities regressed spontaneously. No recurrence occurred, and the child remained neurologically intact. Total disappearance of the masses as well as normal brain and cerebrovascular anatomy were confirmed by angiography, MRI, and MRA. Over a follow-up period of 17 years, the patient did not develop complications. He had perfect clinical tolerance and resumed a normal life.