[show abstract][hide abstract] ABSTRACT: A, Microsurgical creation of the venous-pouch arterial-bifurcation aneurysm in the rabbit. An artificial arterial bifurcation is created between the right (1) and left (2) common carotid artery. Then a venous pouch (asterisk) is sutured into the bifurcation, mimicking the aneurysm sac. B, 2D DSA anteroposterior view of the partially embolized aneurysm shows the unoccluded part of the aneurysm (red arrow). The small white arrows indicate the longitudinal radiopaque markers of the Neuroform stent. C, The borders of the contrast medium or coil-filled aneurysm parts and the orifice plane are outlined (green). The area filled or refilled by contrast medium within the total aneurysm area is defined on the posttreatment DSA, by using an attenuation-gradient-based distinction (red area within the aneurysm total area).
[show abstract][hide abstract] ABSTRACT: A, Overview: right common carotid artery (1), left common carotid artery (2), and recanalized volume of the aneurysm (red arrow). B, The aneurysm outer border can be well-delineated (red arrow). C, The aneurysm outer border is circled in red. B and C, The embolized part of the aneurysm directly borders the left common carotid artery (white arrow, 2). D, The recanalized part (red arrow) of the aneurysm can be well identified. E, The recanalized aneurysm part is false-color-labeled (red area), and the aneurysm outer border is encircled (red). F, The 3D reconstruction: right common carotid artery, (1) left common carotid artery, (2) false-color-labeled embolized aneurysm volume (yellow), and false-color-labeled recanalized aneurysm volume (green).
[show abstract][hide abstract] ABSTRACT: For embolized cerebral aneurysms, the initial occlusion rate is the most powerful parameter to predict aneurysm rerupture and recanalization. However, the occlusion rate is only estimated subjectively in clinical routine. To minimize subjective bias, computer occlusion-rating (COR) was successfully validated for 2D images. To minimize the remaining inaccuracy of 2D-COR, COR was applied to 1.5T 3D MR imaging.
Twelve experimental rabbit aneurysms were subjected to stent-assisted coil embolization followed by 2D DSA and 3D MR imaging. Subjective occlusion-rate (SOR) was estimated. Linear parameters (aneurysm length, neck width, parent vessel diameter) were measured on 2D DSA and 3D MR imaging. The occlusion rate was measured by contrast medium-based identification of the nonoccluded 2D area/3D volume in relation to the total aneurysm 2D area/3D volume. 2D and 3D parameters were statistically compared.
There were no limiting metallic artifacts by using 3D MR imaging. Linear parameters (millimeters) were nearly identical on 2D DSA and 3D MR imaging (aneurysm length: 7.5 ± 2.6 versus 7.4 ± 2.5, P = .2334; neck width: 3.8 ± 1.0 versus 3.7 ± 1.1, P = .6377; parent vessel diameter: 2.7 ± 0.6 versus 2.7 ± 0.5, P = .8438), proving the high accuracy of 3D MR imaging. COR measured on 3D MR imaging was considerably lower (61.8% ± 26.6%) compared with the following: 1) 2D-COR (65.6% ± 27.1%, P = .0537) and 2) 2D-SOR estimations (69.2% ± 27.4%, P = .002). These findings demonstrate unacceptable bias in the current clinical standard SOR estimations.
3D-COR of embolized aneurysms is easily feasible. Its accuracy is superior to that of the clinical standard 2D-SOR. The difference between 3D-COR and 2D-COR approached statistical significance. 3D-COR may add objectivity to the ability to stratify the risk of rerupture in embolized cerebral aneurysms.
American Journal of Neuroradiology 12/2011; 33(4):661-6. · 3.17 Impact Factor
[show abstract][hide abstract] ABSTRACT: Despite rapid advances in the development of materials and techniques for endovascular intracranial aneurysm treatment, occlusion of large broad-neck aneurysms remains a challenge. Animal models featuring complex aneurysm architecture are needed to test endovascular innovations and train interventionalists.
Eleven adult female New Zealand rabbits were assigned to 3 experimental groups. Complex bilobular, bisaccular, and broad-neck venous pouch aneurysms were surgically formed at an artificially created bifurcation of both CCAs. Three and 5 weeks postoperatively, the rabbits underwent 2D-DSA and CE-3D-MRA, respectively.
Mortality was 0%. We observed no neurologic, respiratory, or gastrointestinal complications. The aneurysm patency rate was 91% (1 aneurysm thrombosis). There was 1 postoperative aneurysm hemorrhage (9% morbidity). The mean aneurysm volumes were 176.9 ± 63.6 mm(3), 298.6 ± 75.2 mm(3), and 183.4 ± 72.4 mm(3) in bilobular, bisaccular, and broad-neck aneurysms, respectively. The mean operation time was 245 minutes (range, 175-290 minutes). An average of 27 ± 4 interrupted sutures (range, 21-32) were needed to create the aneurysms.
This study demonstrates the feasibility of creating complex venous pouch bifurcation aneurysms in the rabbit with low morbidity, mortality, and high short-term aneurysm patency. The necks, domes, and volumes of the bilobular, bisaccular, and broad-neck aneurysms created are larger than those previously described. These new complex aneurysm formations are a promising tool for in vivo animal testing of new endovascular devices.
American Journal of Neuroradiology 02/2011; 32(4):772-7. · 3.17 Impact Factor
[show abstract][hide abstract] ABSTRACT: The choice of the experimental aneurysm model is essential for valid embolization-device evaluations. So far, the use of the rabbit venous pouch arterial bifurcation aneurysm model has been limited by demanding microsurgery, low aneurysm patency rates, and high mortality. This study aimed to facilitate microsurgery and to reduce mortality by optimized peri-/postoperative management.
Aneurysms were created in 16 New Zealand white rabbits under general intravenous anesthesia. Using modified microsurgical techniques, we sutured a jugular vein pouch into a bifurcation created between both CCAs. Aggressive anticoagulation (intraoperative intravenous: 1000-IU heparin, 10-mg acetylsalicylic acid/kg; postoperative subcutaneous: 14 days, 250-IU/kg /day heparin) and prolonged postoperative anesthesia (fentanyl patches: 12.5 μg/h for 72 hours) were applied. Angiographic characteristics of created experimental aneurysms were assessed.
The reduced number of interrupted sutures and aggressive anticoagulation caused no intra-/postoperative bleeding, resulting in 0% mortality. Four weeks postoperation, angiography showed patency in 14 of 16 aneurysms (87.5%) and Ohshima type B bifurcation geometry. Mean values of parent-artery diameters (2.3 mm), aneurysm lengths (7.9 mm), and neck widths (4.1 mm) resulted in a mean 1.9 aspect ratio.
Compared with historical controls, the use of modified microsurgical techniques, aggressive anticoagulation, and anesthesia resulted in higher aneurysm patency rates and lower mortality rates in the venous pouch arterial bifurcation aneurysm model. Gross morphologic features of these aneurysms were similar to those of most human intracranial aneurysms.
American Journal of Neuroradiology 10/2010; 32(1):165-9. · 3.17 Impact Factor
[show abstract][hide abstract] ABSTRACT: Recent studies have focused on mechanical thrombectomy as a means to reduce the time required for revascularization and increase the revascularization rate in acute stroke. To date no systematic evaluation has been made of the different mechanical devices in this novel and fast-developing field of endovascular interventions. To facilitate such evaluations, we developed a specific in vivo model for mechanical thrombectomy that allows visualization of dislocation or fragmentation of the thrombus during angiographic manipulation.
Angiography and embolization with a preformed thrombus was performed in 8 swine. The thrombus was generated by mixing 25 IU bovine thrombin and 10 mL autologous blood. For visualization during angiography, 1 g barium sulfate was added.
The preformed thrombus exhibited mechanical stability, reproducibility, and high radiographic absorption, providing excellent visibility during angiography. The setting allowed selective embolization of targeted vessels without thrombus fragmentation. Despite the application of barium sulfate no local or systemic reaction occurred. Histologic evaluation revealed no intimal damage caused by the thrombus or contrast agent washout.
The model presented here allows selective and reliable thromboembolization of vessels that reproduce the anatomic and hemodynamic situation in acute cerebrovascular stroke. It permits visualization of the thrombus during angiography and intervention, providing unique insight into the behavior of both thrombus and device, which is potentially useful in the development and evaluation of mechanical clot retrieval in acute cerebrovascular stroke.
American Journal of Neuroradiology 27(6):1357-61. · 3.17 Impact Factor
[show abstract][hide abstract] ABSTRACT: A case of Lhermitte-Duclos disease (LDD, dysplastic gangliocytoma) with atypical vascularization is reported. LDD is a rare cerebellar mass lesion which may be associated with Cowden's syndrome and the PTEN germline mutation.
A 61-year-old male presented 15 years before with a transient episode of unspecific gait disturbance. Initial magnetic resonance (MR) imaging revealed a right-sided, diffuse, nonenhancing cerebellar mass lesion. No definitive diagnosis was made at that time, and the symptoms resolved spontaneously. 15 years later, the patient presented with acute onset of vomiting associated with headache and ataxic gait. MR imaging showed a progression of the lesion with occlusive hydrocephalus. The lesion depicted a striated pattern characteristic for LDD with T1-hypointense and T2-hyperintense bands, nonenhancing with contrast. After resection of the mass lesion, the cerebellar and hydrocephalic symptoms improved rapidly. The pathological examination confirmed the diagnosis of dysplastic gangliocytoma (WHO Grade I) with enlarged granular and molecular cell layers, reactive gliosis and dysplastic blood vessels. No other clinical features associated with Cowden's syndrome were present.
This case illustrates that LDD with atypical vascularization is a slow-growing posterior fossa mass lesion which may remain asymptomatic for many years. Timing of surgical treatment and extent of resection in patients with LDD is controversial. The typical features on standard T1-/T2-weighted MR imaging allow a diagnosis without surgery in most cases. The authors believe that the decision to treat in these cases should be based on clinical deterioration.