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

Lateral Spinal Artery Aneurysm Causing Subarachnoid Hemorrhage: Literature Review and Case Report

Ruptured aneurysms of the lateral spinal artery (LSA) causing subarachnoid hemorrhage (SAH) are exceptionally rare. Unlike common aneurysms in the circle of Willis, LSA aneurysms present unique diagnostic and therapeutic challenges due to their complex anatomy. We reviewed the literature, examining case reports detailing LSA aneurysm occurrences, diagnoses, treatments, and complications, and our subsequent analysis highlights the clinical presentations, imaging findings, treatment methods, and anatomical features of the LSA. We identified 10 patients from 7 case reports of LSA aneurysm presenting with SAH, and combined with the present case, this comprised a total of 11 patients. An initial CT angiography identified LSA aneurysm in only 2 of 11 patients, while 5 cases were detected in transfemoral cerebral angiography. Seven patients had stenosis or occlusion of nearby arteries. Among the 10 patients treated, 7 underwent microsurgical clipping, and 3 had endovascular treatment; complications included PICA infarction and subdural hematoma. LSA aneurysms, though rare, should be considered in differential diagnoses of posterior fossa SAH. An accurate diagnosis often requires repeated imaging. It is proposed to individualize treatment strategies based on the unique anatomical structure and hemodynamic conditions of each patient, utilizing both endovascular and surgical approaches. Understanding the vascular anatomy and collateral pathways of the LSA is crucial for improving diagnostic accuracy and treatment outcomes.

Preoperative Spinal Arterial Supply Mapping Using Non-Selective Cone Beam Computed Tomography before Complex Aortic Repair

Pre-op spinal arterial mapping is crucial for complex aortic repair. This study explores the utility of non-selective cone beam computed tomography (CBCT) for pre-operative spinal arterial mapping to identify the Adamkiewicz artery (AKA) in patients undergoing open or endovascular repair of the descending thoracic or thoracoabdominal aorta at risk of spinal cord ischemia. Pre-operative non-selective dual-phase CBCT after intra-aortic contrast injection was performed in the aortic segment to be treated. The origin of detected AKA was assessed based on image fusion between CBCT and pre-interventional computed tomography angiography. Then, the CBCT findings were compared with the incidence of postoperative spinal cord ischemia (SCI). Among 21 included patients (median age: 68 years, 20 men), AKA was detected in 67% within the explored field of view, predominantly from T7 to L1 intercostal and lumbar arteries. SCI occurred in 14%, but none when AKA was not detected (p < 0.01). Non-selective CBCT for AKA mapping is deemed safe and feasible, with potential predictive value for post-surgical spinal cord ischemia risk. The study concludes that non-selective aortic CBCT is a safe and feasible method for spinal arterial mapping, providing promising insights into predicting post-surgical SCI risk.

Adult Infratentorial Pial Arteriovenous Fistula Treated with Detachable Coils: A Case Report and a Review of Literature

An appropriate therapeutic option for pial arteriovenous fistula (PAVF) can vary according to the angioarchtecture of the lesion. We present a case of adult infratentorial PAVF treated by transarterial coil embolization. A 26-year-old man was referred to our institution for an asymptomatic intracranial vascular lesion. Cerebral angiograms revealed PAVF fed by three arteries in the right cerebellomedullary cistern. The feeding arteries were accurately identified by three-dimensional rotational angiography and were successfully embolized using coils while normal arterial flow was preserved. This case report suggests that stepwise transarterial coil embolization can cure PAVF under detailed evaluation of its angioarchitecture.

Review of spinal dural arteriovenous fistulas: Challenges, diagnostics, management, and pathophysiology

Spinal dural arteriovenous fistulae are rare, spinal vascular malformations that commonly present with progressive myelopathy in a specific demographic and are treatable with surgery (preferred) and/or endovascular embolization. PubMed and Google Scholar were searched with terms including but not limited to "spinal dural arteriovenous fistula", "imaging", "management" "surgery vs embolization", "outcomes", "pathogenesis" to find relevant studies, including emerging research. The purpose of this literature review is to highlight presentation, imaging characteristics, management strategies, pathophysiology, and future directions for these rare but distinct entities.

Ophthalmic artery angioplasty for age-related macular degeneration

BACKGROUND

There is considerable overlap of contributors to cardiovascular disease and the development of age-related macular degeneration (AMD). Compromised ocular microcirculation due to aging and vascular disease contribute to retinal dysfunction and vision loss. Decreased choroidal perfusion is evident in eyes with dry AMD and is thought to play a role in retinal pigment epithelial dysfunction, the rate of development of geographic atrophy, and the development of neovascularization. The aim of the study was to demonstrate that AMD is correlated with a compromised blood flow in the ocular pathway and show OA angioplasty as a potential treatment of late-stage AMD.

METHODS

Based on the potential for the ophthalmic artery (OA) to be an anatomical target for the treatment of AMD as outlined above, five patients were found to be eligible for compassionate use treatment, presenting clinically significant late-stage AMD with profound vision loss in one or both eyes, and are included in this retrospective study.

RESULTS

OA narrowing, or significant calcium burden at the ophthalmic segment of the internal carotid artery compromising the origin of the OA was confirmed in all cases. Subsequent OA cannulation was achieved in all patients with some difficulty. Subjective patient reports indicated that all patients perceived a benefit following the procedure; however, improved postoperative visual acuity did not confirm that perceived benefit for one of the patients.

CONCLUSIONS

Feasibility and safety of the OA angioplasty were demonstrated, and a benefit perceived in five patients with profound vision loss and a desire to achieve improved quality of life. A clinical trial with controlled schedule, imaging, and methodologies is needed to confirm these results.

Principles, techniques and applications of high resolution cone beam CT angiography in the neuroangio suite

The aim of this review is to describe the acquisition and reformatting of state of the art high resolution cone beam CT (HR-CBCT) and demonstrate its role in multiple neurovascular conditions as a tool to improve the understanding of disease and guide therapeutic decisions. First, we will review the basic principle of CBCT acquisition, followed by the injection protocols and the reformatting paradigms. Next, multiple applications in different pathological conditions such as aneurysms, arteriovenous malformations, dural arteriovenous fistulas, and stroke will be described. HR-CBCT angiography, widely available, is uniquely useful in certain clinical scenarios to improve the understanding of disease and guide therapeutic decisions. It rapidly is becoming an essential tool for the contemporary neurointerventionalist.AChoAho.

Spinal Epidural Lipomatosis Associated with Intrathecal Flow Voids: Demonstration of Engorged Veins Using Flat Panel Catheter Angiotomography

We present a case of a 54-year-old male with spinal epidural lipomatosis who had associated flow voids on magnetic resonance imaging with dilated intrathecal vessels. During spinal angiogram, 20s DynaCT (flat panel catheter angiotomography) was utilized to demonstrate the intrathecal engorged veins. Venous engorgement of epidural venous plexus has been previously described in epidural lipomatosis; however, dilated intrathecal perimedullary veins have not been demonstrated by imaging. We have described the utility of flat panel catheter angiotomography in understanding venous disorders in such patients.

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.

Spinal vascular lesions: anatomy, imaging techniques and treatment

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Vascular myelopathies include different aetiology and mechanism of damage.

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The level of the lesion and the localization within the SC correlates with the clinical symptoms.

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CT, MRI and angiography are essential for diagnosis and treatment playing a complementary role.

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MRI is the gold standard for the evaluation of spinal cord lesions.

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Spinal angiography is the gold standard for evaluation of spinal cord vasculature and vascular malformations.

Background

Vascular lesions of the spinal cord are rare but potentially devastating conditions whose accurate recognition critically determines the clinical outcome. Several conditions lead to myelopathy due to either arterial ischemia, venous congestion or bleeding within the cord. The clinical presentation varies, according with the different aetiology and mechanism of damage.

Purpose

The aim is to provide a comprehensive review on the radiological features of the most common vascular myelopathies, passing through the knowledge of the vascular spinal anatomy and the clinical aspects of the different aetiologies, which is crucial to promptly address the diagnosis and the radiological assessment.

Detection of the common origin of the radiculomedullary artery with the feeder of spinal dural arteriovenous fistula using slab maximum intensity projection image

PURPOSE

Endovascular therapy to the spinal dural arteriovenous fistula (SDAVF) with a common origin of the radiculomedullary artery and the feeder of the shunt has the risk of spinal cord infarction. This study aimed to retrospectively assess the detection rate of normal spinal arteries from the feeder of SDAVF.

METHODS

We retrospectively collected the angiographic and clinical data of SDAVFs. This study included 19 patients with 20 SDAVF lesions admitted to our department between January 2007 and December 2018. We assessed the detection rate of normal radiculomedullary artery branched from the feeder of SDAVF between the period using the image intensifier (II) and flat panel detector (FPD) and evaluated the treatment results.

RESULTS

The detection rates of the radiculomedullary artery branched from the feeder of SDAVF were 10% (1/10 lesions) during the II period and 30% (3/10 lesions) during the FPD period. During the FPD period, all normal radiculomedullary arteries branched from the feeder were only detected on slab maximum intensity projection (MIP) images of rotational angiography, and we could not detect them in 2D or 3D digital subtraction angiography. All lesions that had a common origin of a normal radiculomedullary artery and the feeder were completely obliterated without complications. There was no recurrence during the follow-up period.

CONCLUSIONS

The flat panel detector and slab MIP images seem to show the common origin of the normal radiculomedullary arteries from the feeder more accurately. With detailed analyses, SDAVF can be safety treated.

Massive Intramedullary Hemorrhage After Subarachnoid Hemorrhage in Patient with Vertebrovertebral Arteriovenous Fistula

BACKGROUND

Hemorrhagic presentations are rare in vertebrovertebral arteriovenous fistula (VVAVF). To the best of our knowledge, this is the first report of a patient initially presenting with subarachnoid hemorrhage and progressing to intramedullary hemorrhage.

CASE DESCRIPTION

The authors report on a 59-year-old man with VVAVF who developed massive intramedullary hemorrhage. Twelve months before ictus, the patient presented with subarachnoid hemorrhage. Although we recommended endovascular surgery, the patient refused treatment. Twelve months after the initial attack, the massive intramedullary hemorrhage in cervical spinal cord caused complete spinal cord injury. Emergent endovascular intervention was performed after the intramedullary hemorrhage, but there was no neurologic improvement.

CONCLUSIONS

Identification of this phenomenon is important in VVAVF because intramedullary hemorrhage dramatically degrades patient outcome. Prompt surgical intervention is mandatory for VVAVF cases presenting with subarachnoid hemorrhage.

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.

Adjunctive Efficacy of Intra-Arterial Conebeam CT Angiography Relative to DSA in the Diagnosis and Surgical Planning of Micro-Arteriovenous Malformations

BACKGROUND AND PURPOSE

Micro-arteriovenous malformations are an underrecognized etiology of intracranial hemorrhage. Our study aimed to assess the adjunctive efficacy of intra-arterial conebeam CTA relative to DSA in the diagnosis and surgical planning of intracranial micro-AVMs.

MATERIALS AND METHODS

We performed a retrospective study of all micro-AVMs (≤1-cm nidus) at our institution. Blinded neuroradiologists qualitatively graded DSA and intra-arterial conebeam CTA images for the detection of specific micro-AVM anatomic parameters (arterial feeder, micronidus, and venous drainer) and defined an overall diagnostic value. Statistical and absolute differences in the overall diagnostic values defined the relative intra-arterial conebeam CTA diagnostic values, respectively. Blinded neurosurgeons reported their treatment approach after DSA and graded the adjunctive value of intra-arterial conebeam CTA to improve or modify treatment. Intra-arterial conebeam CTA efficacy was defined as interobserver agreement in the relative intra-arterial conebeam CTA diagnostic and/or treatment-planning value scores.

RESULTS

Ten patients with micro-AVMs presented with neurologic deficits and/or intracranial hemorrhages. Both neuroradiologists assigned a higher overall intra-arterial conebeam CTA diagnostic value (P < .05), secondary to improved evaluation of both arterial feeders and the micronidus, with good interobserver agreement (τ = 0.66, P = .018) in the relative intra-arterial conebeam CTA diagnostic value. Both neurosurgeons reported that integrating the intra-arterial conebeam CTA data into their treatment plan would allow more confident localization for surgical/radiation treatment (8/10; altering the treatment plan in 1 patient), with good interobserver agreement in the relative intra-arterial conebeam CTA treatment planning value (τ = 0.73, P = .025).

CONCLUSIONS

Adjunctive intra-arterial conebeam CTA techniques are more effective in the diagnostic identification and anatomic delineation of micro-AVMs, relative to DSA alone, with the potential to improve microsurgical or radiosurgery treatment planning.

Spinal dural arteriovenous fistulas: the most frequent vascular malformations of the spinal cord

Spinal dural arteriovenous fistulas are produced by direct communication between the arterial and venous systems of the spinal cord, causing hypertension in the latter with spinal cord dysfunction. It is a rare pathology with unknown etiology and non-specific clinical symptoms that usually results in a delayed diagnosis. Often radiologists are the first to guide the disease towards an adequate diagnosis. Characteristic findings can be seen through MR or MR angiography, and may even locate the fistula in a high percentage of cases, although the pathology must be confirmed by spinal angiography. There are two treatment modalities: endovascular and surgical therapy. Endovascular treatment has improved in recent years with the advantages of a less invasive approach and is therefore usually chosen as primary therapy. In this article we review the main clinical manifestations, imaging findings and treatment of this pathology.

Angiographic and Clinical Characteristics of Thoracolumbar Spinal Epidural and Dural Arteriovenous Fistulas

BACKGROUND AND PURPOSE

The purpose of this study is to compare the angiographic and clinical characteristics of spinal epidural arteriovenous fistulas (SEAVFs) and spinal dural arteriovenous fistulas (SDAVFs) of the thoracolumbar spine.

METHODS

A total of 168 cases diagnosed as spinal dural or extradural arteriovenous fistulas of the thoracolumbar spine were collected from 31 centers. Angiography and clinical findings, including symptoms, sex, and history of spinal surgery/trauma, were retrospectively reviewed. Angiographic images were evaluated, with a special interest in spinal levels, feeders, shunt points, a shunted epidural pouch and its location, and drainage pattern, by 6 readers to reach a consensus.

RESULTS

The consensus diagnoses by the 6 readers were SDAVFs in 108 cases, SEAVFs in 59 cases, and paravertebral arteriovenous fistulas in 1 case. Twenty-nine of 59 cases (49%) of SEAVFs were incorrectly diagnosed as SDAVFs at the individual centers. The thoracic spine was involved in SDAVFs (87%) more often than SEAVFs (17%). Both types of arteriovenous fistulas were predominant in men (82% and 73%) and frequently showed progressive myelopathy (97% and 92%). A history of spinal injury/surgery was more frequently found in SEAVFs (36%) than in SDAVFs (12%; P=0.001). The shunt points of SDAVFs were medial to the medial interpedicle line in 77%, suggesting that SDAVFs commonly shunt to the bridging vein. All SEAVFs formed an epidural shunted pouch, which was frequently located in the ventral epidural space (88%) and drained into the perimedullary vein (75%), the paravertebral veins (10%), or both (15%).

CONCLUSIONS

SDAVFs and SEAVFs showed similar symptoms and male predominance. SDAVFs frequently involve the thoracic spine and shunt into the bridging vein. SEAVFs frequently involve the lumbar spine and form a shunted pouch in the ventral epidural space draining into the perimedullary vein.

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.

Spinal intraarterial computed tomography angiography as an effective adjunct for spinal angiography

OBJECT

Spinal digital subtraction angiography (DSA) is indispensable for the precise diagnosis of spinal vascular lesions and the assessment of blood supply to the spinal cord. However, comprehensive spinal DSA covering multiple segments requires repetition of selective catheterization into small segmental arteries, which is time consuming, sometimes difficult, and hazardous. The authors investigated the usefulness of CT angiography with intraarterial contrast injection (IA-CTA) as a preliminary study preceding spinal DSA. With the advent of multidetector CT, it is feasible to obtain images of the spinal cord vasculature instantaneously overa number of segments.

METHODS

A total of 56 patients with lesions involving the spinal vasculature underwent IA-CTA with 64- or 320-row detector CT in advance of comprehensive spinal DSA. Contrast material was injected via a pigtail catheter placed at the aorta in proximity to the segments of interest. Scanning was repeated twice to obtain arterial- and venous-phase images to differentiate between the arterial and venous components. The spinal arteries were identified by paging the various multiplanar reconstruction images and tracing the vessels from the aorta. Spinal DSA was subsequently performed by guiding selective catheterization to the feeding segments in reference to the IA-CTA findings. Visualization of the segmental arteries, normal spinal arteries, and abnormal vessels during IA-CTA was investigated and compared with that obtained during spinal DSA.

RESULTS

In all 56 patients, spinal IA-CTA successfully enabled visualization of the spinal vessels, including the radicular arteries and the anterior spinal artery. Below the aortic arch, all segmental arteries were identified clearly. The segmental arteries, radiculomedullary arteries, spinal arteries, and abnormal vessels were traced from the aorta, which would be the target of selective catheterization. In 3 (6.8%) patients, IA-CTA revealed severe aortic atherosclerosis and occlusion of some segmental arteries. The information obtained was useful for directing selective catheterization studies. The findings of IA-CTA corresponded well with those of spinal DSA.

CONCLUSIONS

IA-CTA is a useful adjunct to spinal DSA for surveying the vasculature surrounding the spinal cord and for orienting selective catheterization. IA-CTA can complement spinal DSA, curtail unnecessary segmental injections, and thus reduce procedural complications.

Transmedullary Venous Anastomoses: Anatomy and Angiographic Visualization Using Flat Panel Catheter Angiotomography

Flat panel catheter angiotomography, a recently developed angiographic technique, offers a spinal equivalent to the venous phase obtained during cerebral angiography. This report of 8 clinical cases discusses the flat panel catheter angiotomography appearance of a type of spinal venous structure until now principally known through the analysis of postmortem material, transmedullary venous anastomosis. The illustrated configurations include centrodorsolateral, median anteroposterior, median anteroposterior with duplicated origin, and combined centrodorsolateral/median anteroposterior transmedullary venous anastomoses, while a pathologic example documents the potential role of transmedullary venous anastomoses as collateral venous pathways. Two of the reported configurations have not been previously documented. Transmedullary venous anastomoses are normal venous structures that need to be differentiated from spinal cord anomalies, such as intramedullary vascular malformations.

Intramedullary hemorrhage from a thoracolumbar dural arteriovenous fistula

BACKGROUND CONTEXT

Spinal dural arteriovenous fistulas (AVFs) are acquired lesions presenting typically with neurologic deficits secondary to chronic congestive myelopathy. The low-flow and low-volume nature of these lesions makes hemorrhage very unlikely, and intramedullary hemorrhage caused by thoracolumbar dural AVFs is exceedingly rare.

PURPOSE

The purpose of this study was to report a case of intramedullary hemorrhage caused by a thoracolumbar dural AVF.

STUDY DESIGN/SETTING

The study design included a case report and review of literature.

METHODS

A case of intramedullary hemorrhage from a thoracolumbar dural AVF was reported, and the literature regarding hemorrhagic presentations of dural AVF was reviewed.

RESULTS

A 66-year-old woman presented with a sudden onset of abdominal pain, paraplegia, sensory loss below the costal margins, and urinary retention. Magnetic resonance imaging scan showed intramedullary hemorrhage with abnormal flow voids raising suspicion of an intramedullary AV malformation. However, subsequent selective spinal angiography demonstrated a spinal dural AVF fed by the T7 intercostal artery and a varix within the draining vein. Complete obliteration of the dural AVF and the varix was achieved via embolization. As far as we are aware, there are only two other similar cases in the literature. Literature review revealed that presentation of thoracolumbar dural AVFs with hemorrhage is frequently associated with accelerated venous flow and the presence of a venous varix.

CONCLUSIONS

Although very unusual, a spinal dural AVF may present with intramedullary hemorrhage, and hemorrhage in such conditions may be associated with an accelerated venous flow and the presence of a venous varix.

Superior performance of cone-beam CT angiography in characterization of intracranial atherosclerosis

Object

Intracranial atherosclerotic disease (ICAD) carries a high risk of stroke. Evaluation of ICAD has focused on assessing the absolute degree of stenosis, although plaque morphology has recently demonstrated increasing relevance. The authors provide the first report of the use of ultra-high-resolution C-arm cone-beam CT angiography (CBCT-A) in the evaluation of vessel stenosis as well as plaque morphology.

Methods

Between August 2009 and July 2012, CBCT-A was used in all patients with ICAD who underwent catheter-based angiography at the authors' institution (n = 18). Lesions were evaluated for maximum degree of stenosis as well as plaque morphological characteristics (ulcerated, calcified, dissected, or spiculated) via digital subtraction angiography (DSA), 3D-rotational angiography (3DRA), and CBCT-A. The different imaging modalities were compared in their assessment of absolute stenosis as well as their ability to resolve different plaque morphologies.

Results

Lesions were found to have similar degrees of stenosis when utilizing CBCT-A compared with 3DRA, but both 3DRA and CBCT-A differed from DSA in their assessment of the absolute degree of stenosis. CBCT-A provided the most detailed resolution of plaque morphology, identifying a new plaque characteristic in 61% of patients (n = 11) when compared with DSA and 50% (n = 9) when compared with 3DRA. CBCT-A identified all lesion characteristics visualized on DSA and 3DRA.

Conclusions

CBCT-A provides detailed spatial resolution of plaque morphology and may add to DSA and 3DRA in the evaluation of ICAD. Further prospective study is warranted to determine any benefit CBCTA-A may provide in clinical decision making and risk stratification over existing conventional imaging modalities.

Radiation exposure of abdominal cone beam computed tomography

PURPOSE

To evaluate patients radiation exposure of abdominal C-arm cone beam computed tomography (CBCT).

METHODS

This prospective study was approved by the institutional review board; written, informed consent was waived. Radiation exposure of abdominal CBCT was evaluated in 40 patients who underwent CBCT during endovascular interventions. Dose area product (DAP) of CBCT was documented and effective dose (ED) was estimated based on organ doses using dedicated Monte Carlo simulation software with consideration of X-ray field location and patients' individual body weight and height. Weight-dependent ED per DAP conversion factors were calculated. CBCT radiation dose was compared to radiation dose of procedural fluoroscopy. CBCT dose-related risk for cancer was assessed.

RESULTS

Mean ED of abdominal CBCT was 4.3 mSv (95 % confidence interval [CI] 3.9; 4.8 mSv, range 1.1-7.4 mSv). ED was significantly higher in the upper than in the lower abdomen (p = 0.003) and increased with patients' weight (r = 0.55, slope = 0.045 mSv/kg, p < 0.001). Radiation exposure of CBCT corresponded to the radiation exposure of on average 7.2 fluoroscopy minutes (95 % CI 5.5; 8.8 min) in the same region of interest. Lifetime risk of exposure related cancer death was 0.033 % or less depending on age and weight.

CONCLUSIONS

Mean ED of abdominal CBCT was 4.3 mSv depending on X-ray field location and body weight.

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.

C-arm Cone Beam Computed Tomography: A New Tool in the Interventional Suite

Introduction: C-arm Cone Beam CT (CBCT) is a technology that is being integrated into many of the newer angiography systems in the interventional suite. Due to its ability to provide cross sectional imaging, it has opened a myriad of opportunities for creating new clinical applications. We review the technical aspects, current reported clinical applications and potential benefits of this technology. Materials and Methods: Searches were made via PubMed using the string “CBCT”, “Cone Beam CT”, “Cone Beam Computed Tomography” and “C-arm Cone Beam Computed Tomography”. All relevant articles in the results were reviewed. Results: CBCT clinical applications have been reported in both vascular and non-vascular interventions. They encompass many aspects of a procedure including preprocedural planning, intraprocedural guidance and postprocedural assessment. As a result, they have allowed the interventionalist to be safer and more accurate in performing image guided procedures. There are however several technical limitations. The quality of images produced is not comparable to conventional computed tomography (CT). Radiation doses are also difficult to quantify when compared to CT and fluoroscopy. Conclusion: CBCT technology in the interventional suite has contributed significant benefits to the patient despite its current limitations. It is a tool that will evolve and potentially become an integral part of imaging guidance for intervention. Key words: Angiogram, Biopsy, Embolisation, Intervention, Stenting, Vascular

The diagnosis of spinal dural arteriovenous fistulas

STUDY DESIGN

Retrospective consecutive case series.

OBJECTIVE

To review and analyze clinical presentations and radiological imaging of 326 consecutive patients with spinal dural arteriovenous fistula (SDAVF) from 2 institutions.

SUMMARY OF BACKGROUND DATA

The clinical presentations of SDAVF are nonspecific. Patients may be initially diagnosed with other spinal diseases. Magnetic resonance imaging (MRI) can reveal spinal cord changes associated with the disorder, but neurosurgeons often overlook these changes.

METHODS

From 1989 to 2009, 326 patients were diagnosed with SDAVF and treated at Qilu Hospital of Shandong University and the Xuanwu Hospital of the Capital University of Medical Sciences. We retrospectively reviewed the clinical records and radiological images of all patients, and collected and analyzed the related data.

RESULTS

Two hundred eighty-two males and 44 females (male/female ratio 6.4:1; mean age, 53.9 yr; SD, 12.1) were included in the study. Fistulas were located at the T7 spinal segment (41, 12.6%), but were more typically found at T5 to L5 (273, 82.5%). The most common initial symptoms were lower extremity weakness (234, 71.8%), sensory disturbance (229, 70.2%), and sphincter disturbance (87, 26.7%). These percentages increased to, 85.6%, 80.8%, and 52.5%, respectively, until patients were properly diagnosed. The mean diagnostic time to SDAVF was 19.9 months (SD, 25.2). Two major changes noted on magnetic resonance images were intramedullary T2-weighted signal hyperintensity (284, 87.1%) and perimedullary dilated vessels (251, 77%). Fistulas were often located outside of the vertebral segments of T2-weighted signal change (P = 0.005). Magnetic resonance angiography and computed tomography angiography of 33 (71.7%) patients revealed perimedullary dilated vessels and precisely located fistulas in 19 (41.3%) patients. Magnetic resonance angiography and computed tomography angiography studies of the perimedullary vessels also led to identification of a second fistula through angiography. Degenerative disc disease and myelitis were the most common misdiagnoses, and the patients were often treated incorrectly.

CONCLUSION

"Worsening" and "symptoms combination" are progression characteristics of SDAVF. Patients should undergo spinal magnetic resonance imaging when they are first suspected to have SDAVF. Magnetic resonance angiography and computed tomography angiography as noninvasive angiography are helpful for diagnosis.

Flat panel catheter angiotomography of the spinal venous system: an enhanced venous phase for spinal digital subtraction angiography

BACKGROUND AND PURPOSE

While spinal DSA remains the reference standard technique for spinovascular imaging, visualizing spinal veins remains challenging due to their small size and motion artifacts. This study evaluates the ability of FPCA to overcome these obstacles.

MATERIALS AND METHODS

Sixty-three FPCAs, performed by intersegmental artery injections in 57 patients, were prospectively evaluated. Entrance skin doses were compared with standard spinal DSA runs, including a venous phase and cerebral FPCAs. FPCA contributions were stratified as 1) provided no added information, 2) complemented spinal DSA findings, 3) assisted therapy planning, and 4) contributed principal diagnostic findings.

RESULTS

No complications were observed. Diagnoses included vascular malformations (44%), stroke (9%), venous anomalies (10%), other (9%), and unremarkable (28%). Mean entrance skin doses were of 419 mGy for FPCA, 161 mGy for spinal DSA with venous phase, and 309 mGy for cerebral FPCAs. FPCA contributed the principal diagnostic finding in 16 cases (25.4%), assisted therapy planning in 13 cases (20.6%), complemented spinal DSA findings in 12 cases (19.1%), and provided no additional information in 20 cases (31.7%). In 8 of these 20 cases, FPCA documented a spinal venous anatomy that was poorly visualized or not visualized on spinal DSA.

CONCLUSIONS

Spinal FPCA is safe, with a moderate increase in radiation dose, compared with spinal DSA with venous phase or cerebral FPCA. It proved particularly valuable for therapy planning and the diagnosis of venous abnormalities. This study suggests that FPCA has an important role to play in the evaluation of the spinal venous system.

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.

Angioarchitecture of Spinal Dural Arteriovenous Fistula - Evaluation with 3D Rotational Angiography

Purpose

The complex angioarchitecture of spinal dural arteriovenous fistulas (SDAVFs) sometimes preclude angiographic analyses or superselective procedures. Therefore, the effectiveness of 3 dimensional rotational angiography (3DRA) as a detailed imaging technique for SDAVFs was evaluated.

Materials and Methods

Of 57 patients with spinal vascular malformations, recent 13 SDAVF patients underwent 3DRA. The advantage of 3DRA compared to digital subtraction angiography (DSA) in imaging SDAVF was assessed. Angioarchitecture of SDAVF was focused on location, number, and course of feeders and draining vein. Appropriate angled views were also selected to reveal the segmental artery and feeders.

Results

3DRA technique provided additional information for imaging evaluation of SDAVFs compared to DSA; the presence of multiple feeders, including their transdural portions, as well as their courses. The contralaterally angled anterior-oblique-caudal (spider) view showed the radicular feeder by separating the intercostal artery and the dorsal muscular branch. The bottom-to-up (tunnel) view was useful for revealing the location (ventral vs. dorsal) including sharp medial turn of the dural feeder. The dual mode, which displays both vessels and bones, revealed the course of the feeders and the fistula related to the spinal bony column.

Conclusion

Because spinal vasculature overlaps in DSA, 3DRA revealed additional information for evaluations of the number and transdural course of fistular feeders in SDAVFs, and it offers working angles to obtain appropriate views.

Feasibility of flat panel angiographic CT after intravenous contrast agent application in the postoperative evaluation of patients with clipped aneurysms

BACKGROUND AND PURPOSE

Important findings, such as aneurysm remnants or major arterial occlusion, can be detected on intra- or postoperative angiography after surgical clipping of intracranial aneurysms. The purpose of this study was to evaluate the feasibility of IV-ACT for the postoperative detection of residual aneurysms and parent vessel patency compared with IA-DSA, which was selected as the standard reference method.

MATERIALS AND METHODS

Twenty-two patients with 27 aneurysms treated by surgical clipping were examined by using both IA-DSA and IV-ACT. Both diagnostic procedures were performed on an FPD-equipped angiography system. Postprocessing of IV-ACT acquisitions was performed on a dedicated workstation producing multiplanar reformations and maximum intensity projections of the clip region and other intracranial arteries. Three interventional neuroradiologists independently evaluated both procedures.

RESULTS

A residual aneurysm was delineated in 10 cases with IA-DSA. Sufficient opacification of the intracranial vessels was assigned in 26 IV-ACT cases. Due to metal artifacts, IV-ACT images were tagged as "not diagnostic" on 8 occasions. In the other 19 aneurysms, a residual aneurysm was delineated in 6 cases-all 6 being true-positive compared with IA-DSA-and was excluded in the remaining 13 cases-all true-negative. Even small aneurysm remnants with a diameter of 1.5 mm were detected with IV-ACT.

CONCLUSIONS

Currently IV-ACT cannot be recommended as a routine tool for postoperative evaluation of clipped aneurysms due to metal artifacts in 30% of the examinations. These artifacts appear with multiple normal-sized or large clips. In patients with single or multiple small clips, IV-ACT can reliably show aneurysm remnants.

Surgical treatment of spinal dural arteriovenous fistulae: a consecutive series of 154 patients

BACKGROUND

Embolization of spinal dural arteriovenous fistulae (SDVAFs) has emerged as an alternative to surgery. However, surgical disconnection is a simple and effective procedure.

OBJECTIVE

To review results and complications of surgical treatment of 154 consecutive SDAVFs.

METHODS

The records of 154 consecutive patients with SDAVFs were retrospectively reviewed.

RESULTS

There were 120 males and 34 females (male/female ratio 3.5:1, mean age 63.6 years). The SDAVFs were located at the thoracic level in 92 patients and at the lumbar and sacral spine levels in 45 and 15 patients, respectively. The most common presenting symptoms were motor dysfunction (65 patients), sensory loss (31 patients), and paresthesias without sensory loss (13 patients). The mean interval from symptom onset to definitive diagnosis was 24.7 months (median 12 months). Surgery resulted in complete exclusion of the fistula at first attempt in 146 patients (95%). There were no deaths or major neurological complications related to the surgery. Six percent of patients experienced subjective or objective worsening of preoperative symptoms and signs by the time of discharge that persisted at follow-up. Other surgical complications consisted of wound infection in 2 patients and deep venous thrombosis in 3. Eight patients were lost to follow-up; 141 patients (96.6%) experienced improvement (120 patients, 82.2%) or stability (21 patients, 14.4%) of motor function at last follow-up compared with their preoperative status. Other symptoms such as numbness, sphincter dysfunction, and dysesthesias/neuropathic pain improved in 51.5%, 45%, and 32.6%, respectively.

CONCLUSION

Surgical obliteration of SDAVFs is safe and very effective. Prognosis of motor function is favorable after surgical treatment.

Volumetric myelographic magnetic resonance imaging to localize difficult-to-find spinal dural arteriovenous fistulas

Although more prevalent in males in the 6th and 7th decade of life, spinal dural arteriovenous fistulas (SDAVFs) are an uncommon cause of progressive myelopathy. Magnetic resonance imaging and more recently Gd bolus MR angiography have been used to diagnose, radiographically define, and preprocedurally localize the contributing lumbar artery. Three-dimensional myelographic MR imaging sequences have recently been developed for anatomical evaluation of the spinal canal. The authors describe 3 recent cases in which volumetric myelographic MR imaging with a 3D phase-cycled fast imaging employing steady state acquisition (PC-FIESTA) and a 3D constructive interference steady state (CISS) technique were particularly useful not only for documenting an SDAVF, but also for providing localization when CT angiography, MR imaging, MR angiography, and spinal angiography failed to localize the fistula. In a patient harboring an SDAVF at T-4, surgical exploration was performed based on the constellation of findings on the PC-FIESTA images as well as the fact that the spinal segments leading to T-4 were the only ones that the authors were unable to catheterize. In a second patient, who harbored an SDAVF at T-6, after 2 separate angiograms failed to demonstrate the fistula, careful assessment of the CISS images led the authors to focus a third angiogram on the left T-6 intercostal artery and to perform superselective microcatheterization. In a third patient with an SDAVF originating from the lateral sacral branch, the PC-FIESTA sequence demonstrated the arterialized vein extending into the S-1 foramen, leading to a second angiogram and superselective internal iliac injections. The authors concluded that myelographic MR imaging sequences can be useful not only as an aid to diagnosis but also for localization of an SDAVF in complex cases.