Efficacy of DynaCT digital angiography in the detection of the fistulous point of dural arteriovenous fistulas

Transvenous embolization along with intraprocedural image fusion technique for complex intracranial dural arteriovenous fistula

PURPOSE

This study aimed to investigate the efficacy and safety of an intraprocedural image fusion technique using flat-panel detector computed tomography-based rotational angiography (FDCT-RA) and image fusion (IF) for the transvenous approach in treating intracranial dural arteriovenous fistulas (dAVFs).

METHODS

A retrospective review was conducted on patients who underwent transvenous embolization for dural AVFs. The patients were classified into two groups according to the treatment technique used: the FDCT-RA and IF technique group and the conventional technique group. The primary outcomes assessed were the angiographic and clinical outcomes, complications, fluoroscopy time, and radiation exposure. Univariate analyses were performed to compare the two treatment modalities.

RESULTS

Eighty-six patients with intracranial dAVFs were treated with transvenous embolization (TVE), of which 37 patients underwent transvenous approach with flat-panel detector computed tomography-based rotational angiography (FDCT-RA) and image fusion (IF) technique used. The FDCT-RA and IF group showed difference in the location of dAVFs, occlusion state of the sinus, and access routes in comparison to the conventional treatment group. The FDCT-RA and IF technique was predominantly used for dAVFs involving the anterior condylar confluence and cavernous sinus with ipsilateral inferior petrosal sinus (IPS) occlusion. Patients treated with this technique demonstrated a higher rate of complete occlusion (91.9%, n = 34) compared to those treated with the conventional technique (79.6%, n = 39), but this difference was not statistically significant (p = 0.136). Although the implementation of this technique during the treatment procedure showed a tendency to decrease both fluoroscopy duration and radiation dose, the observed results did not reach statistical significance (p = 0.315, p = 0.130).

CONCLUSION

The intraprocedural image fusion technique using FDCT-RA for transvenous treatment of intracranial dAVFs could provide help in treatment of dAVFs of certain locations or access routes. It might provide aid in microcatheter navigation, without increasing the radiation exposure and fluoroscopy time.

Head-Mounted Augmented Reality in the Planning of Cerebrovascular Neurosurgical Procedures: A Single-Center Initial Experience

BACKGROUND

Augmented reality (AR) technology has played an increasing role in cerebrovascular neurosurgery over the last 2 decades. Hence, we aim to evaluate the technical and educational value of head-mounted AR in cerebrovascular procedures.

METHODS

This is a single-center retrospective study of patients who underwent open surgery for cranial and spinal cerebrovascular lesions between April and August 2022. In all cases, the Medivis Surgical AR platform and HoloLens 2 were used for preoperative and intraoperative (preincision) planning. Surgical plan adjustment due to the use of head-mounted AR and subjective educational value of the tool were recorded.

RESULTS

A total of 33 patients and 35 cerebrovascular neurosurgical procedures were analyzed. Procedures included 12 intracranial aneurysm clippings, 6 brain and 1 spinal arteriovenous malformation resections, 2 cranial dural arteriovenous fistula obliterations, 3 carotid endarterectomies, two extracranial-intracranial direct bypasses, two encephaloduroangiosynostosis for Moyamoya disease, 1 biopsy of the superficial temporal artery, 2 microvascular decompressions, 2 cavernoma resections, 1 combined intracranial aneurysm clipping and encephaloduroangiosynostosis for Moyamoya disease, and 1 percutaneous feeder catheterization for arteriovenous malformation embolization. Minor changes in the surgical plan were recorded in 16 of 35 procedures (45.7%). Subjective educational value was scored as "very helpful" for cranial, spinal arteriovenous malformations, and carotid endarterectomies; "helpful" for intracranial aneurysm, dural arteriovenous fistulas, direct bypass, encephaloduroangiosynostosis, and superficial temporal artery-biopsy; and "not helpful" for cavernoma resection and microvascular decompression.

CONCLUSIONS

Head-mounted AR can be used in cerebrovascular neurosurgery as an adjunctive tool that might influence surgical strategy, enable 3-dimensional understanding of complex anatomy, and provide great educational value in selected cases.

Nidus delineation and dosimetric comparison in arteriovenous malformation in stereotactic radiosurgery by using MRI and 3DCT angiography

Purpose/Objectives

Accurate delineation of target is key to any successful radiosurgery. C-arm Dyna CT/ 3DCT angiography (3DCTA) has the potential of improving the accuracy of nidus delineation in intracranial arteriovenous malformations (AVM) due to high temporo-spatial resolution of vessel architecture. Here, we present a comparison of nidus delineation and dosimetric parameters between digital 3DCTA and MRI.

Materials/Methods

Ten consecutive patients treated for intracranial AVMs were included in this study. All patients underwent MRI/MRA, and 3DCTA and all images were co-registered. AVM were delineated using 3DCTA (GTV_3DCTA) and contrast enhanced MRI/MRA (GTV_MRI). Hausdorff distance (HD) matrices and dice similarity coefficient (DSC) matrices were analysed. Stereotactic radiosurgery plans were developed for both the volumes for all patients and statistical analysis were performed with T-test.

Results

Mean volumes of GTV_3DCTA and GTV_MRI were 1.771 cc (SD 1.794cc, range 0.124-4.191cc) and 2.183cc (SD 2.16cc, range 0.221-6.133cc), respectively. Significant deviation (p=0.018) was found when taking GTV_MRI as a primary and comparing it to GTV_3DCTA (MD=0.723cc±0.816cc). Similar result was observed with GTV_3DCTA as primary and GTV_MRI as secondary (MD=0.188cc, SD=0.193cc, p=0.024). Maximum HD was in the range of 1.71 to 7.44mm (mean=4.27mm, SD=1.56). For GTV_3DCTA based plans, significant deviation was found between GTV_MRI and GTV_3DCTA in dose coverage and the mean difference was 22.17% (SD 16.73). In GTV_MRI based plans, the mean CIRTOG deteriorated from 1.33 to 2.18 for GTV_MRI and GTV_3DCTA, respectively. Significant deviation was found in CI_RTOG (0.005) and mean deviation was 0.86(SD=0.72) when comparing GTV_MRI and GTV_3DCTA. Highly significant (p=0.002) deviation was found in CI_Paddick between GTV_MRI and GTV_3DCTA for GTV_MRI based plans with mean difference of 0.26(SD=0.4, for GTV_MRI=0.3, GTV_3DCTA=0.46).

Conclusion

Nidus volume was significantly altered with the use of 3DCTA compared to that of MRA/MRI images. Multimodality imaging is crucial for accurate target delineation, and successful radiosurgical obliteration of nidus.

Preoperative Embolization of Spinal Metastatic Tumor: The Use of Selective Computed Tomography Angiography for the Detection of Radiculomedullary Arteries

Introduction

Preoperative embolization for metastatic spinal cord compression (MSCC) has a risk of spinal ischemia. This study aimed to assess the efficacy and safety of preoperative embolization in patients with MSCC and evaluate the use of computed tomography (CT) angiography for the detection of the radiculomedullary arteries (RMA).

Methods

This retrospective study included 20 patients (12 men and 8 women; median age, 66 years), who underwent preoperative embolization before a decompression surgery, which corresponded to 22 embolization procedures. The detection ability of RMA was evaluated using angiography and selective CT angiography. Surgical data including intraoperative blood loss and transfusion were also evaluated.

Results

Six RMAs were identified at the levels of affected vertebrae and one level above and below in the diagnostic spinal angiography. In addition to spinal angiography, adjunctive selective CT angiography allowed visualization of another five RMAs. Overall, 11 RMAs were identified in 9 patients. Preoperative embolization was successfully achieved in all patients. As regards complications related to embolization procedure, palsy exacerbated in one patient (4.5%), which improved postoperatively. During the surgical procedure, the mean intraoperative blood loss was 353.4±254.2 mL without intraoperative transfusion in all patients.

Conclusions

The present study showed small amounts of intraoperative blood loss without any severe complications related to preoperative embolization. Selective CT angiography was a useful technique to detect RMAs and contributed to the safety of preoperative embolization.

Adjunctive efficacy of intra-arterial cone-beam computed tomography angiography in the endovascular treatment of vertebra-venous fistula

Vertebro–venous fistula (VVF) refers to an abnormal arteriovenous shunt connecting the extracranial vertebral artery and the paraspinal venous structures. Coil embolization is the mainstay treatment of choice for VVF, and accurate definition of the endovascular target is mandatory. Traditionally, catheter-based angiograms are used for treatment planning, but those images lack bony information to delineate the precise relationship of the drainage veins to the spinal structure. Herein, we presented two VVF cases and demonstrated how we used intra-arterial cone-beam computed tomography angiography (IA-CBCTA) to determine the safe embolization zone for dense coil packing. We propose that IA-CBCTA is a useful adjunct in the endovascular planning of VVF by offering an image consisting of bony and vascular information.

Diagnostic accuracy of three-dimensional-rotational angiography and heavily T2-weighted volumetric magnetic resonance fusion imaging for the diagnosis of spinal arteriovenous shunts

BACKGROUND

Spinal arteriovenous shunts (SAVSs) are rare entities occurring in various areas, from the craniocervical junction to the sacral level. Recently, better understanding of SAVS angioarchitecture and elucidation of its pathogenesis have become possible with the advancement of imaging techniques. However, the utility of fusing different image modalities for SAVS diagnostics has not been determined. This study aimed to investigate whether three-dimensional-rotational angiography (3D-RA) and 3D-heavily T2-weighted volumetric MR (3D-MR) fusion imaging would improve the diagnostic accuracy for SAVSs.

METHODS

We retrospectively reviewed 12 SAVSs in 12 patients. Assessment of 3D-RA and 3D-RA/3D-MR fusion images for SAVS was performed by seven blinded reviewers. The final diagnosis was performed by two interventional neuroradiologists with extensive experience, and the interobserver agreement between the reviewers and the final diagnosis was calculated using κ statistics. The comparison of the interobserver agreement between 3D-RA and 3D-RA/3D-MR fusion images was performed for the diagnosis of SAVS subtypes. We also statistically compared the image-quality gradings (on a 4-grade scale) to delineate the 3D relationship between vascular malformations and the surrounding anatomical landmarks.

RESULTS

The interobserver agreement for the 3D-RA/3D-MR fusion images was substantial (κ=0.7071) and higher than that for the 3D-RA images (κ=0.3534). Significantly better image quality grades were assigned to 3D-RA/3D-MR fusion images than to 3D-RA images (p<0.0001) for the evaluation of the examined 3D relationships.

CONCLUSION

The 3D-RA/3D-MR fusion images provided better interobserver agreement of SAVS subtype diagnosis, allowing for detailed evaluation of the SAVS anatomical structures surrounding the shunt.

Usefulness of preoperative cone beam computed tomography and intraoperative digital subtraction angiography for dural arteriovenous fistula at craniocervical junction: Technical case report

Background:

Direct surgery is commonly selected for the treatment of cranio-cervical junction dural arteriovenous fistula and its outcome is more satisfactory than that of embolization. Intraoperative treatment evaluation is relatively easy in embolization, whereas in direct surgery it can be difficult.

Case Description:

A 67-year-old male suffered a subarachnoid hemorrhage. On three-dimensional (3D) images of preoperational cone-beam computed tomography (CBCT), the structure of the draining vein was depicted in detail along with the surrounding bone structures. The radial artery penetrated the dura mater, and it was found that there were two veins derived from the radiculospinal vein; one was the anterior radicular vein descending toward the dorsal side (the shallow layer of the surgical field) and the other was the anterior spinal medullary vein ascending toward the ventral side (the deep layer of the surgical field) and flowing out to the anterior spinal vein.

Conclusion:

Without detailed assessments with preoperative CBCT, the surgery might have been done with dissection of only the anterior radicular vein in the shallow layers. For identification of the draining vein located deep in the surgical field, such as the cranio-cervical junction, careful assessments using 3D CBCT images are important.

Selective and super-selective C-arm based cone beam CT angiography (CBCTA) with DynaCT for CyberKnife radiosurgery planning of intracranial arteriovenous malformations (AVMs)

BACKGROUND

Successful radiosurgery for intracranial arteriovenous malformations (AVMs) requires accurate delineation of the nidus in 3D. Exact targeting and precise equipment is needed to achieve obliteration of the nidus while minimizing toxicity to the surrounding brain. In some micro-AVMs and poorly visible AVMs we have used cone beam CT angiography (CBCTA) with selective and super-selective angiography where a micro-catheter is advanced into the feeding arteries- to assist with nidus definition for CyberKnife radiosurgery planning.

METHODS

Four patients who had AVMs inadequately visualized with MRI, MRA, CT, CTA, and dynamic CT angiography (dCTA) were identified for selective angiography (2 had super-selective angiography) for CyberKnife radiosurgery. The mean age at the time of treatment was 45 years (range: 22 - 71 years). All patients had suffered prior hemorrhage and were deemed inoperable. Super-selective angiography was done under general anesthesia to minimize motion artefact and the risk of arterial dissection. Angiography was performed using the biplane angiographic suite (ArtisQ; Siemens). Cone beam reconstructions were performed using DynaCT software. For each scan, volumetric data was acquired over 20 seconds in a single rotation of the C-arm mounted flat-panel detector cone-beam CT system. The data set was imported into the CyberKnife TPS and co-registered with the treatment planning CT, T2 MRI and Toshiba dCTA. Delineation of the AVM nidus was performed by the multi-disciplinary AVM team.

RESULTS

There were no adverse events related to the angiography or radiosurgery treatment. CBCTA data sets created using DynaCT were accurately co-registered with the treatment planning scans in the CyberKnife treatment planning system (Multiplan). For all 4 patients, feeding arteries, draining veins and nidi were clearly visualized and used to develop radiosurgery plans. Mean nidus size was 0.45cc (range: 0.07 - 1.00cc).

CONCLUSIONS

For intracranial micro-AVMs and AVMs otherwise poorly visualized using DSA, MRA, CTA or dCTA, selective and super-selective CBCTA images (created using DynaCT) can be successfully imported into the CyberKnife TPS to assist in nidus delineation. Advancement of a micro-catheter into the feeding arteries to allow continuous contrast injection during volumetric scanning constitutes super-selective CBCTA. This technique provides superior visualization of micro-AVMs and should be utilized for radiosurgery planning of poorly visualized AVMs.

Efficacy of Cone Beam Computed Tomography in Treating Cavernous Sinus Dural Arteriovenous Fistula

BACKGROUND

Exact identification of feeding arteries, shunt points, and draining veins is essential in treating cavernous sinus dural arteriovenous fistula (CS dAVF). In addition to digital subtraction angiography (DSA) and 3-dimensional rotational angiography (3DRA), high-resolution cone beam computed tomography (CBCT; especially 80-kv high-resolution cone beam computed tomography) have been performed in recent years. We evaluated the efficacy of CBCT in treating CS dAVF.

METHODS

Eight CS dAVFs were treated with endovascular embolization between January 2013 and December 2016. We retrospectively examined these cases regarding information from DSA, 3DRA, and CBCT with contrast medium.

RESULTS

Although all procedures can evaluate feeding arteries, shunt points, and draining veins, CBCT can provide the best definition of feeders and their course through the bony structures and the compartment of CS. Therefore, CBCT with placed microcatheter in the CS can reveal whether the microcatheter is set at the appropriate compartment to be embolized.

CONCLUSIONS

The efficacy of CBCT in treating dAVF is illustrating the relationships among the bony structures and feeders, compartment of CS, and the position of the microcatheter. Detailed information obtained with CBCT can lead to fewer complications and more effective treatment.

Digital Subtraction Angiography-Dynavision in Pretreatment Planning for Embolization of Dural Arterio-Venous Fistulas

BACKGROUND AND PURPOSE

We have found DSA-Dynavision with multiplanar reconstruction very helpful in understanding the complex anatomy and planning of treatment of carotico-cavernous fistulas. The purpose of our study was to examine whether using DSA-Dynavision in pretreatment planning results in better outcome after endovascular treatment of dural arterio-venous fistulas (dAVFs).

METHODS

Patients with dAVF treated with endovascular embolization were retrospectively identified from our interventional neuroradiology database. Patients were assessed and divided into those with DSA-Dynavision and those without. They were compared for procedural time, angiographic evidence of cure, rates of resolution of cortical venous reflux (CVR), complications, and need for postembolization surgery.

RESULTS

Eighty-six percent of 28 patients (mean age 57 years, range 1.67-84 years) had Borden type 3 DAVF; 7% had Borden type 2; and 7% had Borden type 1. DSA-Dynavision was used in 14 of 28 (50%) patients. Fewer patients with DSA-Dynavision required postendovascular embolization surgery (7% vs. 50%, P = .01) and fewer DSA-Dynavision patients had CVR postprocedure (29% vs. 71%, P = .023). Mean procedural time (207 vs. 249 minutes; P = .40); permanent neurological complication rates (7% vs. 7%, P = 1.0); rate of immediate angiographic occlusion (64% vs. 29%, P = .061), and reported resolution of symptoms (79% vs. 53%, P = .18) were not significantly different. There was no significant difference in follow-up (mean: 75 vs 120 weeks, P = .47).

CONCLUSION

The use of DSA-Dynavision in planning of endovascular treatment of dAVF is associated with higher rates of elimination of CVR and less need for postembolization surgery.

CT reconstruction and MRI fusion of 3D rotational angiography in the evaluation of pediatric cerebrovascular lesions

PURPOSE

Complex neurovascular lesions in children require precise anatomic understanding for treatment planning. Although 3DRA is commonly employed for volumetric reformation in neurointerventional procedures, the ability to reconstruct this data into CT-like images (3DRA-CT) is not widely utilized. This study demonstrates the feasibility and usefulness of 3DRA-CT and subsequent MRI fusion for problem solving in pediatric neuroangiography.

METHODS

This retrospective study includes 18 3DRA-CT studies in 16 children (age 9.6 ± 3.8 years, range 2-16 years) over 1 year. After biplane 2D-digital subtraction angiography (DSA), 5-second 3DRA was performed with selective vessel injection either with or without subtraction. Images were reconstructed into CT sections which were post-processed to generate multiplanar reformation (MPR) and maximum intensity projection (MIP) images. Fusion was performed with 3D T1 MRI images to precisely demonstrate neurovascular relationships. Quantitative radiation metrics were extracted and compared against those for the entire examination and for corresponding biplane 2D-DSA acquisitions.

RESULTS

In all 18 cases, the 3DRA procedure and MRI fusion were technically successful and provided clinically useful information relevant to management. The unsubtracted and subtracted 3DRA acquisitions were measured to deliver 5.9 and 132.2%, respectively, of the mean radiation dose of corresponding biplane 2D-DSA acquisitions and contributed 1.2 and 12.5%, respectively, to the total procedure dose.

CONCLUSION

Lower radiation doses, high spatial resolution, and multiplanar reformatting capability make 3DRA-CT a useful adjunct to evaluate neurovascular lesions in children. Fusing 3DRA-CT data with MRI is an additional capability that can further enhance diagnostic information.

Computational Modeling of Venous Sinus Stenosis in Idiopathic Intracranial Hypertension

BACKGROUND AND PURPOSE

Idiopathic intracranial hypertension has been associated with dural venous sinus stenosis in some patients, but the hemodynamic environment of the dural venous sinuses has not been quantitatively described. Here, we present the first such computational fluid dynamics model by using patient-specific blood pressure measurements.

MATERIALS AND METHODS

Six patients with idiopathic intracranial hypertension and at least 1 stenosis or atresia at the transverse/sigmoid sinus junction underwent MR venography followed by cerebral venography and manometry throughout the dural venous sinuses. Patient-specific computational fluid dynamics models were created by using MR venography anatomy, with venous pressure measurements as boundary conditions. Blood flow and wall shear stress were calculated for each patient.

RESULTS

Computational models of the dural venous sinuses were successfully reconstructed in all 6 patients with patient-specific boundary conditions. Three patients demonstrated a pathologic pressure gradient (≥8 mm Hg) across 4 dural venous sinus stenoses. Small sample size precludes statistical comparisons, but average overall flow throughout the dural venous sinuses of patients with pathologic pressure gradients was higher than in those without them (1041.00 ± 506.52 mL/min versus 358.00 ± 190.95 mL/min). Wall shear stress was also higher across stenoses in patients with pathologic pressure gradients (37.66 ± 48.39 Pa versus 7.02 ± 13.60 Pa).

CONCLUSIONS

The hemodynamic environment of the dural venous sinuses can be computationally modeled by using patient-specific anatomy and physiologic measurements in patients with idiopathic intracranial hypertension. There was substantially higher blood flow and wall shear stress in patients with pathologic pressure gradients.

Percutaneous Glycerol Rhizotomy for Trigeminal Neuralgia Using a Single-Plane, Flat Panel Detector Angiography System: Technical Note

Percutaneous treatments for trigeminal neuralgia (TN) including glycerol rhizotomy (GR), radiofrequency thermocoagulation (RT), and balloon compression (BC) are effective for patients with medical comorbidities and risk factors of microvascular decompression (MVD). These procedures are usually performed under fluoroscopy. Surgeons advance the needle to the trigeminal plexus through the foramen ovale while observing landmarks of fluoroscopic images; however, it is sometimes difficult to appropriately place the needle tip in Meckel's cave. We present the technical details of percutaneous GR using a single-plane, flat panel detector angiography system to check the needle positioning. When the needle tip may be located near the trigeminal cistern, three-dimensional (3-D) bone images are taken with cone-beam computed tomography (CT). These images clearly show the position of the needle tip in Meckel's cave. If it is difficult to place it through the foramen ovale, surgeons perform cone beam CT to observe the actual position of the needle tip at the skull base. After confirming the positional relation between the needle tip and foramen ovale, surgeons can advance it in the precise direction. In 10 procedures, we could place the nerve-block needle in about 14.5 minutes on average without complications. We think that our method is simple and convenient for percutaneous treatments for TN, and it may be helpful for surgeons to perform such treatments.

Artery of the Superior Orbital Fissure: An Undescribed Branch from the Pterygopalatine Segment of the Maxillary Artery to the Orbital Apex Connecting with the Anteromedial Branch of the Inferolateral Trunk

BACKGROUND AND PURPOSE

Some branches of the internal maxillary artery have anastomoses with the inferolateral trunk that are important as intracranial-extracranial collateral pathways and as dangerous anastomoses for transarterial embolization of these branches. We present here an undescribed branch potentially anastomosing with the anteromedial branch of the inferolateral trunk, which is provisionally named the artery of the superior orbital fissure, defined as an arterial branch from the pterygopalatine segment of the maxillary artery to the orbital apex at the superior orbital fissure.

MATERIALS AND METHODS

Two neuroradiologists reviewed 3D and MPR images of the external and/or common carotid artery with particular interest paid to the artery of the superior orbital fissure in 54 patients who underwent 3D angiography with a field of view covering the pterygopalatine fossa and the cavernous sinus. The underlying diseases in these patients were 17 parasellar hypervascular lesions (including 13 cavernous sinus dural arteriovenous fistulas and 4 meningiomas), 18 internal carotid artery stenoses/occlusions, and 19 other diseases.

RESULTS

The artery of the superior orbital fissure was identified in 20 of 54 patients; it arose at the pterygopalatine segment of the maxillary artery, either singly or from a common trunk with the artery of the foramen rotundum, and ran upward to reach the superior orbital fissure. It anastomosed with the anteromedial branch of the inferolateral trunk at the superior orbital fissure with blood flow toward the cavernous sinus (n = 14) and/or the ophthalmic artery (n = 2). It was more prominent in parasellar hypervascular lesions and internal carotid artery stenoses/occlusions than in other diseases.

CONCLUSIONS

The artery of the superior orbital fissure, a remnant of the anastomotic artery, was often identified, especially in patients with parasellar hypervascular lesions.

Evaluation of Intracranial Dural Arteriovenous Fistulas: Comparison of Unenhanced 3T 3D Time-of-flight MR Angiography with Digital Subtraction Angiography

PURPOSE

We compared gross characterization of intracranial dural arteriovenous fistulas (DAVFs) between unenhanced 3-tesla 3-dimensional (3D) time-of-flight (TOF) magnetic resonance angiography (MRA) and digital subtraction angiography (DSA).

METHODS

We subjected 26 consecutive patients with intracranial DAVF to unenhanced 3T 3D TOF MRA and to DSA. Two independent sets of observers inspected the main arterial feeders, fistula site, and venous drainage pattern on MRA and DSA images. Interobserver and intermodality agreements were assessed by k statistics.

RESULTS

Interobserver agreement was excellent for fistula site (κ = 0.919; 95% confidence interval [CI], 0.805 to 1.000), good for main arterial feeders (κ = 0.711; 95% CI, 0.483 to 0.984), and very good for venous drainage (κ = 0.900; 95% CI, 0.766 to 1.000). Intermodality agreement was excellent for fistula site (κ = 0.968; 95% CI, 0.906 to 1.000) and good for main arterial feeder (κ = 0.809; 95% CI, 0.598 to 1.000) and venous drainage (κ = 0.837; 95% CI, 0.660 to 1.000).

CONCLUSION

Gross characterization of intracranial DAVF was similar for both imaging modalities, but unenhanced 3T 3D TOF MRA cannot replace DSA.

Shunted pouches of cavernous sinus dural AVFs: evaluation by 3D rotational angiography

INTRODUCTION

The aims of this study were to evaluate the angioarchitecture of cavernous sinus dural arteriovenous fistulas (CSdAVFs), including the number and location of shunted pouches (SPs), and to evaluate whether the location and number of the SPs affect the outcomes of transvenous embolization of CSdAVFs.

METHODS

Nineteen consecutive cases of CSdAVFs that underwent rotational angiography and transvenous embolization were reviewed. Multiplanar reconstruction images of rotational angiography and selective angiography were reviewed with particular interest in the SPs. Relationships of the locations and number of SPs with the results of transvenous embolization were statistically analyzed.

RESULTS

All cases showed SPs, with numbers ranging from 1 to 4 (mean, 2.2). The location of the SPs was "posteromedial" in 16, "posterolateral" in 13, "lateral" in 6, and "medial" in 3 patients. Six cases showed posteromedial SPs alone, and three cases showed posterolateral SPs alone. The other 10 cases showed multiple locations of SPs. All cases were treated by transvenous embolization with sinus packing (n = 11) or selective embolization of the SP (n = 8). Complete occlusion of dAVF was obtained in 16 cases immediately after embolization. Locations of SPs and drainage types were significantly associated with the immediate angiographic results (p < 0.01).

CONCLUSION

The SP of CSdAVFs is often multiple and is located posteriorly to the CS. The number and location of SPs affect immediate angiographic results of transvenous embolization.

DynaCT imaging for intraprocedural evaluation of flow-diverting stent apposition during endovascular treatment of intracranial aneurysms

The treatment of large, complex intracranial aneurysms is being increasingly performed using flow-diverting stents (FDS) such as the Pipeline Embolization Device (PED; ev3, Irvine, CA, USA). Malapposition of a FDS to the parent artery wall decreases the likelihood of aneurysm obliteration and increases the risk of both immediate and delayed complications. DynaCT scanning (Siemens Medical Solutions, Erlangen, Germany) is a novel imaging modality which uses a flat plane detector to generate CT images using the same C-arm employed for digital subtraction angiography. We present a 40-year-old woman with an unruptured, 11 mm cavernous internal carotid artery aneurysm who was treated with endovascular obliteration using a PED. Intraprocedural DynaCT scan performed after PED deployment demonstrated incomplete stent apposition to the parent vessel which could not be detected on digital subtraction angiography alone. Balloon angioplasty was performed to improve apposition of the stent to the vessel wall. There were no procedural or clinical complications. The aneurysm shrank in size at follow-up angiography 6 months after the procedure and will be monitored for progressive occlusion. While gross stent malapposition is readily evident after stent deployment, minor instances of malapposition may be undetectable by standard angiography. Therefore the use of DynaCT imaging may improve intraprocedural stent visualization and potentially avert long-term endovascular aneurysm treatment complications associated with inadequate stent apposition.

Use of Dyna CT in evaluation and treatment of pseudoaneurysm secondary to craniofacial tumor resection: Case report and diagnostic implications

Background:

Digital subtraction angiography (DSA) is considered the gold standard for the evaluation of head and neck vascular abnormalities. It serves as a useful diagnostic and, in many cases, therapeutic tool for treatment of acute head and neck bleeding.

Case Description:

We report the case of a patient who presented with life threatening, uncontrollable epistaxis several weeks after resection of a large recurrent chondrosarcoma of the nasal cavity and anterior skull base. A DSA study, with an adjunctive C-arm computed tomography (CT) (Dyna CT), was ultimately helpful in revealing and precisely localizing a large anterior ethmoidal artery pseudoaneurysm adjacent to the tumor resection cavity.

Conclusion:

This additional information helped define the arterial anatomy in postoperative region, allowed precise localization and direct ligation of the pseudoaneurysm to resolve the bleeding with a favorable patient outcome.

Superselective shunt occlusion for the treatment of cavernous sinus dural arteriovenous fistulae

BACKGROUND

In treating cavernous sinus dural arteriovenous fistulae (CSdAVFs), transvenous embolization of the whole affected sinus is usually performed, which may result in the disturbance of normal venous drainage or permanent cranial nerve palsy.

OBJECTIVE

To describe superselective shunt occlusion of CSdAVFs.

METHODS

Between July 2005 and August 2011, we had 20 consecutive cases of CSdAVFs. In 14 cases (70%), we could detect the restricted locus of arteriovenous shunts by 3-dimensional rotational angiography and/or superselective arteriography. After navigating the microcatheter to the shunt segment, consecutive superselective arteriovenography was performed to confirm the location of the microcatheter at the proper position.

RESULTS

In 12 of 14 cases (85.7%) in which the shunt was restricted, coiling only in the small venous pouch or compartment, which was just downstream of the shunt point, led to complete disappearance of the shunt without obliterating the entire sinus. No recurrence or permanent cranial nerve palsy was observed during the follow-up period with a mean of 46 months (range, 3-69 months) in 12 cases treated by superselective shunt occlusion.

CONCLUSION

This technique, which enables complete extirpation of shunts by small amounts of coils, is a feasible way to treat CSdAVFs with excellent mid- to long-term results. Understanding of the angioarchitecture by 3-dimensional rotational angiography and consecutive superselective arteriovenography was useful. This method should be considered before sinus packing or mere obliteration of dangerous venous outlets.

Novel application of 3-dimensional rotational C-arm conebeam computed tomography angiography for metastatic hypervascular tumor mass in the spine

STUDY DESIGN

This is a case report.

OBJECTIVE

To report a 3-dimensional (3D) rotational C-arm conebeam computed tomography (CT) (DynaCT) angiography generating computed tomographic data concurrently with spinal angiographic datasets. This technology allowed 3D modeling of the anterior spinal arterial supply in juxtaposition to a hypervascular tumor mass, thus affording unprecedented guidance in presurgical planning.

SUMMARY OF BACKGROUND DATA

An enhanced demonstration of spatial relationships between the vascular elements and their adjacent soft-tissue structures is needed to visualize the minute anterior spinal artery optimally.

METHODS

A 76-year-old male with a history of renal cell carcinoma metastasis to the T6 vertebra 1 year prior, presented with worsening myelopathy caused by severe spinal cord compression at T6 level, and a plan for surgical decompression was established. Because of the hypervascular nature of this renal cell carcinoma metastasis, preoperative embolization was requested to minimize blood loss during the operation. A digital subtraction angiogram identified the major arterial contribution to the tumor to also supply the radiculomedullary branch to the anterior spinal artery. To further characterize this blood supply, a rotational DynaCT angiography was performed.

RESULTS

The rotationally acquired data were processed generating volumetric CT datasets demonstrating the 3D relationships of the anterior spinal artery, the blood supply to the tumor and the adjacent soft-tissue and bony structures. A shared blood supply to both the tumor mass and the anterior spinal artery from the left T6 segmental artery was confirmed. The dual nature of this blood supply presented increased risk of ischemic spinal cord injury by possible nontarget embolization. Therefore, the embolization was deferred.

CONCLUSION

The DynaCT angiography precisely characterized the complex blood supply of a hypervascular vertebral tumor mass in relation to a shared arterial supply to the thoracic spinal cord. The optimal visualization properly aided presurgical planning.

LEVEL OF EVIDENCE

N/A.

The use of susceptibility-weighted imaging as an indicator of retrograde leptomeningeal venous drainage and venous congestion with dural arteriovenous fistula: diagnosis and follow-up after treatment

BACKGROUND

Retrograde leptomeningeal venous drainage (RLVD) in dural arteriovenous fistulas (DAVFs) is associated with intracerebral hemorrhage and nonhemorrhagic neurological deficits or death. Angiographic evidence of RLVD is a definite indication for treatment, but less invasive methods of identifying RLVD are required.

OBJECTIVE

To evaluate the efficacy of susceptibility-weighted magnetic resonance imaging (SWI) in detecting RLVD in DAVFs.

METHODS

We retrospectively identified 17 DAVF patients who had angiographic evidence of RLVD and received treatment. Conventional angiography and SWI were assessed at pretreatment and posttreatment time points. The presence of RLVD on SWI was defined as cortical venous hyperintensity, and the presence of venous congestion on SWI venograms was defined as increased caliber of cortical or medullary veins.

RESULTS

Cortical venous hyperintensity was identified in pretreatment SWI of 15 patients. Cortical venous hyperintensity was absent in early posttreatment SWI, consistent with the absence of RLVD in posttreatment angiography, in all but one of these patients. In 2 patients, cortical venous hyperintensity was identified during follow-up, indicating the recurrence of RLVD. Cortical venous hyperintensity was not identified in the pretreatment SWI of 2 patients despite angiographic evidence of RLVD. Venous congestion was identified in pretreatment SWI venograms of 11 patients and had an appearance similar to that identified from angiography. Venous congestive signs improved over the follow-up period.

CONCLUSION

The presence of SWI hyperintensity within the venous structure could be a useful indicator of RLVD in DAVF patients. Thus, SWI offers a noninvasive alternative to angiography for the identification of RLVD in pretreated and posttreated DAVF patients.

Angioarchitecture of transverse-sigmoid sinus dural arteriovenous fistulas: evaluation of shunted pouches by multiplanar reformatted images of rotational angiography

BACKGROUND AND PURPOSE

Recognition of shunted pouches dural arteriovenous fistula allows us to treat the disease effectively by selective embolization of the pouches at first. However, the shunted pouches in transverse-sigmoid sinus dural arteriovenous fistulas have not been well-documented. Our aim was to evaluate the angioarchitecture of transverse-sigmoid sinus dural arteriovenous fistulas, including the frequency and location of shunted pouches and their feeding arteries. MATERIALS AND METHODS Twenty-five consecutive cases of TSS-DAVFs that underwent rotational angiography and transvenous embolization between 2008 and 2011 were reviewed. Multiplanar reformatted images of rotational angiography and selective angiography were reviewed with a particular focus on the shunted pouches.

RESULTS

All 25 cases showed SPs, with numbers ranging from 1 to 4 pouches (mean, 2.35). The SPs were located at the transverse-sigmoid junction in 16, close to the vein of Labbé in 9, at the dorsal-to-sigmoid sinus in 9, inferior to the sigmoid sinus in 6, at the sigmoid-jugular junction in 5, and inferior to the transverse sinus or the sinus confluence in 14. The SP at the sigmoid sinus was frequently fed by the jugular branch of the ascending pharyngeal artery and the stylomastoid artery. The SP at the transverse-sigmoid junction and the vein of Labbé was fed by the petrosal/petrosquamous and posterior branches of the middle meningeal artery and the transosseous branches of the occipital artery. The SP inferior to the transverse sinus and the sinus confluence was fed by the transosseous branches of the occipital artery and the posterior meningeal artery. All cases were successfully treated by transvenous embolization with sinus packing (n = 13) or selective embolization of the SP (n = 12).

CONCLUSIONS

The presence of SP is a common angioarchitecture of TSS-DAVFs. Identification of the SPs would be useful for their treatment.

Turn-back embolization technique for effective transvenous embolization of dural arteriovenous fistulas

For effective transvenous embolization of DAVFs, it is important to place coils at the shunting venous pouch in the initial step of the procedure. When it was difficult to navigate a microcatheter to the shunting venous pouch due to the anatomic relationship of approach routes with targeted pouches, we navigated the microcatheters by a "turn-back technique" within the involved sinuses into the target pouches. Complete occlusion or regression of the DAVF was obtained in all cases.

Imaging of cerebral arteriovenous malformations and dural arteriovenous fistulas

Imaging plays a major role in the identification, grading, and treatment of cerebral arteriovenous malformations and cerebral dural arteriovenous fistulas. Digital subtraction angiography is the gold standard in the diagnosis and characterization of these vascular malformations, but advances in both magnetic resonance imaging and computed tomography, including advanced imaging techniques, have provided new tools for further characterizing these lesions as well as the surrounding brain structures that may be affected. This article discusses the role of conventional as well as advanced imaging modalities that are providing novel ways to characterize these vascular malformations.

Simultaneous arteriovenous shunting and venous congestion identification in dural arteriovenous fistulas using susceptibility-weighted imaging: initial experience

In this short report, we describe the potential contribution of SWI in the noninvasive evaluation of DAVFs. SWI images were compared with DSA for the identification of the location of the fistulous point, the presence of CVR, and the presence of the PPP. In 5 of 6 patients, it was possible to identify the fistulous locations depicted as hyperintensity within venous structures. Cortical venous reflux was underestimated on SWI in 3 cases of robust CVR and not identified in 2 cases of less severe CVR. The PPP seen on angiograms correlated anatomically with increased number, caliber, and tortuosity of hypointense veins seen on SWI. Furthermore, SWI was superior to conventional MR imaging in the detection of these dilated veins. These preliminary results suggest an important role for SWI in the detection and assessment of the complex hemodynamics associated with DAVFs.

CT angiography as a screening tool for dural arteriovenous fistula in patients with pulsatile tinnitus: feasibility and test characteristics

BACKGROUND AND PURPOSE

The diagnosis of intracranial DAVF with noninvasive cross-sectional imaging such as CTA is challenging. We sought to determine the sensitivity and specificity of CTA compared with cerebral angiography for DAVF in patients presenting with PT.

MATERIALS AND METHODS

Following approval of the institutional review board, we reviewed all patients who underwent CTA for PT from 2004 to 2009 and collected clinical and imaging data. Seven patients with PT and proved DAVF and 7 age- and sex-matched control patients with PT but no DAVF composed the study group. CTA images were blindly interpreted by 2 experienced neuroradiologists for the presence of 5 variables: asymmetric arterial feeding vessels, "shaggy" appearance of a dural venous sinus, transcalvarial venous channels, asymmetric venous collaterals, and abnormal size and number of cortical veins. Asymmetric attenuation of jugular veins was additionally assessed.

RESULTS

The presence of arterial feeders showed good test characteristics for screening, with a sensitivity of 86% (95% CI, 42-99) and a specificity of 100% (95% CI, 52-100). A shaggy sinus or tentorium was highly specific: sensitivity of 42% (95% CI, 11-79) and specificity of 100% (95% CI, 56-100). The presence of transcalvarial venous channels demonstrated a poor sensitivity of 29% (95% CI, 5-70) but a high specificity 86% (95% CI, 42-99). CT attenuation of the jugular veins showed statistically significant asymmetry in the DAVF group versus the control group (P < .05).

CONCLUSIONS

CTA can be used to screen for DAVF in patients with PT. The presence of asymmetrically visible and enlarged arterial feeding vessels has a high sensitivity and specificity for the diagnosis of DAVF.

Use of angiographic CT imaging in the cardiac catheterization laboratory for congenital heart disease

OBJECTIVES

This study sought to retrospectively evaluate our initial experience using angiographic computed tomography (ACT) in a pediatric cardiac catheterization laboratory.

BACKGROUND

ACT provides cross-sectional CT images from a rotational angiography run using a C-arm mounted flat-panel detector in the interventional suite. A 3-dimensional (3D) angiographic image can be created from the CT volume set and used in real time during the procedure. To our knowledge, its use has never previously been described for congenital heart disease.

METHODS

3D reconstructions were created and we retrospectively reviewed cases during our first year of ACT use. Images obtained were independently evaluated to determine their diagnostic utility. Radiation dose reduction protocols were defined using phantom testing and radiation dose calculation.

RESULTS

ACT was used during 41 cardiac catheterizations in patients at a median age of 5.1 years (range: 0.4 to 58.8 years) for evaluation of: right ventricular outflow tract (RVOT)/central pulmonary arteries (PAs) in 20; cavopulmonary connection (CPC) in 11; pulmonary veins in 5; distal PAs in 4; and other locations in 5. Four subjects had 2 anatomic areas studied by ACT. The mean contrast volume for ACT was 1.2 ± 0.4 ml/kg. Diagnostic-quality imaging was obtained in 71% of cases: 13/20 RVOT/central PAs; 9/11 CPC; 4/5 pulmonary veins; 2/4 distal PAs; and 4/5 others. In 12 cases, ACT contributed to clinical outcomes beyond standard angiography. Radiation dose reduction protocols allowed ACT to be comparable in exposure to a standard biplane cineangiogram.

CONCLUSIONS

Diagnostic-quality imaging can be obtained using ACT in 71% of cases without a significant increase in contrast or radiation exposure. In certain cases, ACT provides additional anatomic detail and may aid complex catheter manipulations. Future work is needed to continue to define applications of this new technology.

Usefulness of C-Arm Cone-Beam Computed Tomography in Endovascular Treatment of Traumatic Carotid Cavernous Fistulas

BACKGROUND

Detailed information about the anatomy of traumatic carotid cavernous fistula (CCF) is required for determining the appropriate treatment strategy.

OBJECTIVE

We report the usefulness of C-arm cone-beam computed tomography (CBCT) for visualizing traumatic CCF during endovascular treatment.

CLINICAL PRESENTATION

A 63-year-old woman presented with right pulsating tinnitus 1 week after a bicycle accident. Right internal carotid angiography demonstrated a right CCF but failed to visualize its precise location because the cavernous portion of the right internal carotid artery (ICA) was hidden by early filling of the cavernous sinus during both conventional digital subtraction angiography (DSA) and 3-dimensional digital angiography.

TECHNIQUE

C-arm CBCT, performed with a flat-panel detector mounted in a C-arm angiographic system, clearly depicted the tear in the medial wall of the C4 segment of the right ICA. Transarterial embolization with coils achieved complete occlusion of the CCF, and the patient's symptoms resolved immediately after the procedure.

CONCLUSION

C-arm CBCT is useful to visualize the communication between the ICA and cavernous sinus and helps to determine the treatment strategy for traumatic CCFs.

3D C-arm conebeam CT angiography as an adjunct in the precise anatomic characterization of spinal dural arteriovenous fistulas

BACKGROUND AND PURPOSE

Precise anatomic understanding of the vascular anatomy of SDAVFs is required before treatment. This study demonstrates the utility of C-arm conebeam CT to locate precisely the fistulous point in SDAVFs and the courses of their feeding arteries and draining veins.

MATERIALS AND METHODS

This retrospective study reports 14 consecutive patients with SDAVFs who underwent DSA and C-arm conebeam CT angiography. SDAVF sites included 5 thoracic, 7 lumbar, and 2 sacral fistulas. Selective DSA initially identified the location and arterial supply of the SDAVF. C-arm conebeam CT angiography was then performed with selective injection into the feeding artery. Reconstructed images were reviewed at a workstation with the referring surgeon, in conjunction with the standard 2D DSA images. The value of C-arm conebeam CT in depicting the fistula and the relationship to adjacent structures was qualitatively assessed.

RESULTS

In all 14 patients, C-arm conebeam CT angiography was technically successful and precisely demonstrated the site of the fistula, feeding arteries, draining veins, and the relationship of the fistula to adjacent osseous structures. Information obtained from the C-arm conebeam CT angiogram was considered useful in all surgically (12 patients) and endovascularly (2 patients) treated SDAVFs.

CONCLUSIONS

3D C-arm conebeam CT angiography is a useful adjunct to 2D DSA in the anatomic characterization of SDAVFs. The technique allowed improved visualization of the vascular anatomy of the SDAVFs and clearer definition of their spatial relationships to adjacent structures.