Perioperative Management of Spinal Arteriovenous Malformation Embolization: Delayed Venous Thrombosis and Implications for Severe Back Pain.

BACKGROUND AND PURPOSE: The prognosis of untreated spinal arteriovenous malformations (SAVMs) is poor. Embolization plays an important role in the management of intramedullary SAVMs. Delayed aggravation due to spinal venous thrombosis following successful embolization has been reported; however, perioperative management strategies to prevent thrombosis have not been explored. We present our single-center experience of SAVM embolization and perioperative management, including anticoagulation. MATERIAL AND METHODS: We retrospectively evaluated 18 patients with SAVMs who underwent transarterial embolization. Perioperative anticoagulation therapy was administered to selected patients. We compared the characteristics of the patients, including perioperative management procedures, between those with and without postoperative worsening following embolization. RESULTS: Acute postoperative worsening within 1 week occurred in 4 (22.2%) patients. Of these, immediate worsening was observed in one patient as a procedure-related complication. Delayed worsening after 24 h was observed in 3 patients, caused by delayed venous thrombosis with severe back pain. Rescue anticoagulation for delayed worsening improved symptoms in two patients. A comparison between patients with and without acute postoperative worsening revealed significant differences in age (median 46.5 vs. 26.5 years, p = 0.009) and the presence of postoperative back pain (75.0% vs. 0%, p = 0.005); however, there was no significant difference in use of selective anticoagulation (p = 0.274). CONCLUSION: The results of this study suggest that SAVM embolization can cause acute worsening due to postoperative venous thrombosis with severe back pain, which may be reversed by anticoagulation therapy. Back pain is an important finding that suggests venous thrombosis, and anticoagulation should be urgently administered.

Comparison of efficacy between clazosentan and fasudil hydrochloride-based management of vasospasm after subarachnoid hemorrhage focusing on older and WFNS grade V patients: a single-center experience in Japan.

Subarachnoid hemorrhage often leads to poor outcomes owing to vasospasm, even after successful aneurysm treatment. Clazosentan, an endothelin receptor inhibitor, has been proven to be an effective treatment for vasospasms in a Japanese randomized controlled trial. However, its efficacy in older patients (≥ 75 years old) and those with World Federation of Neurosurgical Societies (WFNS) grade V has not been demonstrated. We retrospectively evaluated the efficacy of clazosentan in older patients and those with WFNS grade V, using real-world data. Patients with subarachnoid hemorrhage treated before and after the introduction of clazosentan were retrospectively evaluated. The patients were categorized into two groups (clazosentan era versus pre-clazosentan era), in which vasospasm management and outcomes were compared. Vasospasms were managed with fasudil hydrochloride-based (pre-clazosentan era) or clazosentan-based treatment (clazosentan era). Seventy-eight patients were included in this study: the clazosentan era (n = 32) and pre-clazosentan era (n = 46). Overall, clazosentan significantly reduced clinical vasospasms (clazosentan era: 31.3% versus pre-clazosentan era: 60.9%, p = 0.01), delayed cerebral ischemia (DCI) (9.4% versus 39.1%, p = 0.004), and vasospasm-related morbidity and mortality (M/M) (3.1% versus 19.6%, p = 0.03). In subgroup analysis of older patients or those with WFNS grade V, no significant difference was observed in clinical outcomes, although both DCI and vasospasm-related M/M were lower in the clazosentan era. Clazosentan was more effective than fasudil-based management in preventing DCI and reducing vasospasm-related M/M. Clazosentan could be used safely in older patients and those with WFNS grade V, although clinical outcomes in these patients were comparable to those of conventional treatment.

Functional characterization of variants found in Japanese patients with hereditary hemorrhagic telangiectasia.

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant form of vascular dysplasia. Genetic diagnosis is made by identifying loss-of-function variants in genes, such as ENG and ACVRL1. However, the causal mechanisms of various variants of unknown significance remains unclear. In this study, we analyzed 12 Japanese patients from 11 families who were clinically diagnosed with HHT. Sequencing analysis identified 11 distinct variants in ACVRL1 and ENG. Three of the 11 were truncating variants, leading to a definitive diagnosis, whereas the remaining eight were splice-site and missense variants that required functional analyses. In silico splicing analyses demonstrated that three variants, c.526-3C > G and c.598C > G in ACVRL1, and c.690-1G > A in ENG, caused aberrant splicing, as confirmed by a minigene assay. The five remaining missense variants were p.Arg67Gln, p.Ile256Asn, p.Leu285Pro, and p.Pro424Leu in ACVRL and p.Pro165His in ENG. Nanoluciferase-based bioluminescence analyses demonstrated that these ACVRL1 variants impaired cell membrane trafficking, resulting in the loss of bone morphogenetic protein 9 (BMP9) signal transduction. In contrast, the ENG mutation impaired BMP9 signaling despite normal cell membrane expression. The updated functional analysis methods performed in this study will facilitate effective genetic testing and appropriate medical care for patients with HHT.

Sinus reconstruction therapy for superior sagittal sinus dural arteriovenous fistula caused by parasagittal meningioma invasion: a case report.

A dural arteriovenous fistula (dAVF) involving the superior sagittal sinus (SSS) is relatively rare, and its clinical course is usually aggressive. Its concomitance with a tumor has rarely been reported. Here, we present a case of SSS dAVF due to meningioma invasion, which was treated with sinus reconstruction and endovascular embolization. A 75-year-old man who had undergone tumor resection for parasagittal meningioma 4 years prior presented with intra-ventricular hemorrhage. Computed tomography angiography and magnetic resonance imaging revealed recurrent tumor invasion into the SSS causing occlusion. Cerebral angiography revealed multiple shunts along the occluded segment of the SSS, diffuse deep venous congestion, and cortical reflux. Borden type 3 SSS dAVF was diagnosed. We first performed direct tumor resection, followed by stenting for the occluded SSS and partial embolization of the shunts. After a 6-month interval, transvenous occlusion of the SSS was performed along the stent, resulting in complete obliteration of the dAVF. Sinus reconstruction therapy was effective in the immediate improvement of venous hypertension, obtaining the access route to the fistulas, and eradicating the shunts.

Detailed Anatomy of Bridging Veins Around the Foramen Magnum: a Multicenter Study Using Three-dimensional Angiography.

BACKGROUND AND PURPOSE: There has been limited literature regarding the bridging veins (BVs) of the medulla oblongata around the foramen magnum (FM). The present study aims to analyze the normal angioarchitecture of the BVs around the FM using slab MIP images of three-dimensional (3D) angiography. METHODS: We collected 3D angiography data of posterior fossa veins and analyzed the BVs around the FM using slab MIP images. We analyzed the course, outlet, and number of BVs around the FM. We also examined the detection rate and mean diameter of each BV. RESULTS: Of 57 patients, 55 patients (96%) had any BV. The median number of BVs was two (range: 0-5). The BVs originate from the perimedullary veins and run anterolaterally to join the anterior condylar vein (ACV), inferior petrosal sinus, sigmoid sinus, or jugular bulb, inferolaterally to join the suboccipital cavernous sinus (SCS), laterally or posterolaterally to join the marginal sinus (MS), and posteriorly to join the MS or occipital sinus. We classified BVs into five subtypes according to the draining location: ACV, jugular foramen (JF), MS, SCS, and cerebellomedullary cistern (CMC). ACV, JF, MS, SCS, and CMC BVs were detected in 11 (19%), 18 (32%), 32 (56%), 20 (35%), and 16 (28%) patients, respectively. The mean diameter of the BVs other than CMC was 0.6 mm, and that of CMC BV was 0.8 mm. CONCLUSION: Using venous data from 3D angiography, we detected FM BVs in most cases, and the BVs were connected in various directions.

De Novo Radicular Arteriovenous Fistula After Treatment of Spinal Arteriovenous Fistula: A Case Report and Literature Review.

De novo spinal dural arteriovenous fistulas (AVFs) have been reported as metachronous AVFs However, metachronous spinal AVFs are extremely rare, and their pathogenesis remains uncertain. We report a case of de novo radicular AVF (RAVF) following treatment for spinal AVF at the craniocervical junction (CCJ). We also reviewed the literature and discussed the pathogenesis of metachronous spinal AVF. A 64-year-old male patient diagnosed with spinal AVF at the CCJ supplied from the right C1 segmental artery was treated with Onyx-18 (eV3 Inc, CA, USA) trans-arterial embolization, resulting in partial occlusion. Angiography showed a slight residual shunt two weeks after the embolization without another shunt lesion. A five-year follow-up spinal angiography showed de novo RAVF at the C4 level and complete occlusion of the first AVF. The second AVF was not treated because it was asymptomatic, and the patient remained asymptomatic. De novo RAVF was found to develop five years after the embolization of a CCJ-spinal AVF in a patient. This is the first case of de novo RAVF post-treatment of a spinal AVF. This case demonstrated that RAVF could develop as an acquired disease.

Successful embolization of ventricular arteriovenous malformation supplied by the choroidal artery: A case report and literature review.

Background: Ventricular arteriovenous malformations (AVMs) are localized in the ventricles and are mainly fed by the anterior choroidal artery (AChoA) and posterior choroidal artery (PChoA). Surgical resection of ventricular AVMs is difficult as the lesions are localized deep in the brain. Therefore, endovascular treatment is expected to treat ventricular AVMs. However, embolization from the AChoA and PChoA carries the risk of ischemic complications. Even though there are some major reports on embolization strategies from the choroidal arteries, embolization of these arteries remains technically challenging. In this article, we report two successful cases of ventricular AVM embolization using AChoA and PChoA. Case Description: Case 1: A 34-year-old male presented with intraventricular hemorrhage (IVH). Subsequently, ventricular AVM embolization in the anterior horn was performed using n-butyl-2-cyanoacrylate (NBCA) through the AChoA and medial PChoA, and complete obliteration was observed without neurological deterioration. Case 2: A 71-year-old female presented with IVH. Subsequently, ventricular AVM embolization in the lateral ventricle was performed through the AChoA and lateral PChoA with Onyx and NBCA, and partial obliteration was observed without complications. Furthermore, Gamma Knife surgery for residual lesions resulted in complete obliteration. Conclusion: Embolization through the choroidal arteries for ventricular AVMs is an effective curative or adjunctive treatment.

Postsurgical dural supply to the spinal cord arteriovenous malformation in spinal arteriovenous metameric syndrome.

Dural supply from the external carotid system in cerebral arteriovenous malformations (AVMs) is well known, but actual angiographic evidence of dural supply to spinal cord AVMs (SCAVMs) has not been reported. Here, we report a case of dural supply to the conus SCAVM in the spinal arteriovenous metameric syndrome segment 25-30. Thirteen years after spinal surgery (T12-L2 laminoplasty), spinal angiography showed multiple dural supplies from the dorsal somatic branches, prelaminar arteries, and radiculomeningeal arteries to the SCAVM at the level of the previous spinal surgery. To the best of our knowledge, this is the first reported case with dural supply to the spinal cord. This case demonstrates that the extradural and extraspinal branches can supply the spinal cord in rare instances of spinal dural adhesions following repeated hemorrhages and surgical intervention under a metameric link background.

Angiographic Index for the Treatment Efficacy and Functional Outcomes of Spinal Cord Arteriovenous Shunts: the Vertebral Blush Sign.

BACKGROUND: The functional outcomes in spinal cord arteriovenous shunts (SCAVSs) are usually unpredictable from current assessments of treatment results. We aimed to investigate and propose a new index marker, the vertebral blush (VB) sign, for assessing the treatment efficacy of SCAVSs. METHODS: This retrospective cohort study enrolled patients diagnosed with SCAVSs between June 2012 and May 2021. The VB sign was defined as the angiographic finding of reappearance or enhanced contrast staining of the vertebral bodies fed by shunt-related arteries observed after shunt occlusion. The primary outcome was the improvement in motor/sensory disturbances or sphincter impairments within 1 year after treatment. The secondary outcome was shunt recanalization. VB sign characteristics and associations with outcomes were analyzed. RESULTS: Of 65 patients with SCAVSs, 57 were eligible for VB sign assessment; among these, there were 26 with the VB sign and 31 without the VB sign. Among vascular shunts perimedullary arteriovenous fistula showed the greatest difference in prevalence rate between those with and without the VB sign (33.3%, n = 9/27 versus 10.0%, n = 3/30; P = 0.031). On multivariable logistic regression analysis, SCAVSs with the VB sign had significantly more favorable outcomes than those without the VB sign (adjusted odds ratio, 5.61; 95% confidence interval, 1.48-21.23; P = 0.01). There was no relationship between the VB sign and secondary outcomes (P = 0.35). CONCLUSION: The VB sign is independently associated with functional recovery after shunt occlusion and could be an assessment tool for the treatment efficacy of SCAVSs.

Pure spinal intraosseous arteriovenous fistula: A case report.

Spinal osseous arteriovenous fistula (AVF) is a rare disease with a characteristic angioarchitecture involving an intraosseous venous pouch (VP) of the vertebral body where the feeders are converging. Using spinal angiography alone, it is difficult to distinguish spinal osseous AVF from classical spinal epidural AVF (EDAVF) with fistulas in the epidural VP and bone erosion because both subtypes have an angiographically similar dilated VP appearance. Thus, spinal osseous AVF may be often misdiagnosed as spinal EDAVF. With advancing imaging techniques, it would be possible to determine the exact location of the fistula. Here, we present the case of a 37-year-old woman with a pure spinal thoracic osseous AVF and radiculopathy. She was diagnosed with spinal intraosseous AVF using high-resolution three-dimensional rotational angiography (3D-RA). The fistula was located in the Th1 lateral mass with a VP where multiple osseous feeders were converging. There was paravertebral venous drainage without intradural venous drainage. Transvenous embolization with Onyx and coils was performed through the azygos vein to the lateral epidural venous plexus, resulting in complete obliteration. This case suggests that 3D-RA reconstructed images are essential for accurate diagnosis and successful treatment of this condition. It is important to occlude only intraosseous VPs by accurate subtype diagnosis. Transvenous embolization is a treatment option for spinal intraosseous AVF with paravertebral epidural venous drainage.

FLOW-diverted Glue Embolization to Target lesions (FLOW-GET) technique for spinal vascular diseases: A technical note.

We present and exemplify the flow-diverted glue embolization to target lesions (FLOW-GET) technique for spinal vascular diseases. In this technique, the occlusion of the posterior intercostal artery or dorsal muscular branch by coils diverts the injected glue from the segmental artery to the target lesions. This technique was applied to a ruptured retrocorporeal artery aneurysm and spinal dural arteriovenous fistulas. The FLOW-GET accomplished the complete obliteration of all lesions. This simple and useful technique can be applied to spinal vascular lesions even if a microcatheter is not placed in proper feeders or advanced close to the shunt points or aneurysms.

Optimal guiding catheter position during advancement of the guiding catheter into the carotid artery from the aortic arch via transfemoral approach.

BACKGROUND: Guiding catheter (GC) advancement into the target carotid artery is a crucial step in neuroendovascular therapy. In difficult anatomies, alternative methods have been reported to overcome difficult carotid access for swift GC advancement. However, studies focusing on the positional relationship between the GC and inner catheter (IC) at the aortic arch are lacking. METHODS: We evaluated the impact of the positional relationship between the GC and IC on whether the GC position affects catheter support or system straightening. We retrospectively reviewed 89 patients who underwent neuroendovascular therapy. We assessed the time to carotid access across difficult arch anatomies. The GC position was divided into Position 1, descending aorta level; Position 2, aortic arch level; and Position 3, origin of the left common carotid artery or innominate artery. We also evaluated the GC support and straightening effects in an in vitro vascular model study. RESULTS: The coaxial catheter flexion angle at the aortic arch was significantly larger when the GC was set to Position 3 (p < 0.0001). A significantly shorter time to carotid access was observed with Positions 2 and 3 than with Position 1 in the difficult arch anatomy group. In the in vitro vascular model evaluation, the catheter support effect significantly increased as the GC position became closer to the IC tip (p < 0.0001) and straightening effect significantly increased as the GC moved to Position 2 from Position 1 (p < 0.0001). CONCLUSION: During GC advancement, the GC positional relationship changed the support of the coaxial system with system straightening. The optimal GC position, Position 3, facilitated swift GC advancement.

Targeted embolisation for coexisting conus medullaris arteriovenous malformation and cauda equina arteriovenous fistulas with a varix on a shared drainer†.

BACKGROUND: The coexistence of vascular malformations in the conus medullaris and cauda equina has been rarely reported, and the complex angioarchitecture in multiple arteriovenous lesions remains poorly understood. CASE DESCRIPTION: A 17-year-old woman presented with a sudden-onset, stepwise worsening of weakness and pain in the bilateral legs. Angiography revealed conus medullaris arteriovenous malformation and cauda equina arteriovenous fistulas. One of the drainers was shared between the coexisting lesions and harboured a varix. Targeted embolisation of a fistulous point in the conus lesion was performed with precaution to prevent occluding the common drainage route, which led to symptom improvement with angiographical diminishment of the varix. CONCLUSIONS: Recognising that communications between drainers can be observed in multiple spinal arteriovenous lesions is important in facilitating a safe embolisation. Cautious assessment of angiogram with fusion images of cone-beam computed tomography and volumetric T2 magnetic resonance imaging can help in establishing the diagnosis and treatment strategy.

Cerebral venous thrombosis associated with hyperhomocysteinemia and iron-deficiency anemia induced by autoimmune gastritis: A case report and literature review.

Cerebral venous thrombosis (CVT) is a rare disease, occurring in 0.5%-1% of all patients with strokes. Systemic and hereditary diseases and traumas are potential causes of CVT. We report a case of CVT and systemic thromboembolism complicated with hyperhomocysteinemia and iron-deficiency anemia caused by autoimmune gastritis. A 47-year-old female patient was admitted to the emergency department due to difficulty in movement, impaired consciousness, and urinary incontinence. Brain computed tomography (CT) and magnetic resonance imaging (MRI) showed bilateral thalamic edema associated with venous sinus thrombosis and embolic cerebral infarction in the deep white matter of the bilateral cerebral hemispheres. In addition, contrast enhanced whole-trunk CT scan showed deep femoral thrombosis and pulmonary artery embolism. She had no medical history of diseases or drug use that may cause thrombosis. Blood test results revealed iron-deficiency anemia and hyperhomocysteinemia, which were determined to be the cause of systemic thromboembolism. The patient tested positive for intrinsic factor antibodies. Moreover, the patient was diagnosed with autoimmune gastritis by gastrointestinal endoscopy. Therapies including anticoagulant and replacement with iron and vitamin B12 were administered. The patient was discharged from the hospital without neurological deficits. A favorable clinical course was achieved with anticoagulant administration and replacement therapy with iron and vitamin B12 for cerebral arteriovenous embolism that developed due to autoimmune gastritis.

Spinal epidural arteriovenous fistula with improved sphincter impairment detected by intraoperative neurophysiological monitoring.

Background: A spinal epidural arteriovenous fistula (SEAVF) is a rare type of arteriovenous shunt that occurs mainly in the thoracic or lumbar spine. Patients with SEAVF develop motor/sensory disturbances of the lower extremities and sphincter dysfunction. Among these symptoms, sphincter impairments show less improvement than others, and its relevance to neurophysiological monitoring has not been documented. Case Description: A 77-year-old woman presented with progressive motor weakness and numbness in the lower extremities and urinary and fecal incontinence. Spinal magnetic resonance imaging showed spinal cord edema in Th5-Th11 and enlarged perimedullary veins. We performed spinal angiography and endovascular treatment under intraoperative neurophysiological monitoring (IOM), including sensory evoked potential (SEP), motor evoked potential (MEP), and bulbocavernosus reflex (BCR) monitoring. Diagnostic angiography revealed a SEAVF with perimedullary venous drainage fed by the left L2 segmental artery. The shunt was completely embolized using N-butyl-2-cyanoacrylate. Although SEP and MEP of the lower legs were recordable during treatment, anal MEP and BCR were not observed. The sphincter symptoms improved 1.5 years after the treatment. Follow-up angiography revealed no shunt recurrence and improved venous congestion. Anal MEP and BCR were detected during angiography, indicating neurophysiological improvement in sphincter function. The prolonged latency of the monitoring suggested a pudendal nerve injury. Conclusion: This case report first described improvement of the IOM correlated with the functional recovery of sphincters after embolization of a SEAVF. Follow-up neurophysiological monitoring is important to assess the functional recovery of the sphincter.

Syndromic vascular malformations related to the PIK3CA and RAS pathways: A clinical and imaging review.

Vascular malformations are a complex and diverse group of disorders. They may enlarge with time, impair quality of life, and even be fatal. While many are sporadic, others are part of inherited syndromes; several gene mutations responsible for vascular anomalies have been identified. The PI3K/AKT/mTOR and RAS/MEK/ERK cascades have been extensively studied, and new molecular agents targeting these cascades are being developed. Diagnostic imaging findings are increasingly used to guide genetic testing, and in some cases, pathognomonic imaging characteristics can lead to a specific diagnosis. We review each of the representative syndromes associated with PIK3CA and RAS cascades, with updates of the latest in clinical and imaging information.

Tortuosity of middle cerebral artery M1 segment and outcomes after mechanical thrombectomy.

BACKGROUND: We aimed to quantify the tortuosity of the middle cerebral artery (MCA) and assess its effects on radiological and clinical outcomes in patients with acute MCA occlusions who received mechanical thrombectomy (MT). METHODS: This retrospective study enrolled 53 patients with acute ischemic stroke due to MCA M1 or M2 segment occlusion who underwent MT using stent retrievers (SRs). Tortuosity index (TI) was defined to quantify the tortuosity of the MCA M1 segment using the following formula: (actual distance / straight distance) × 100. For each patient, four TIs were measured in the anteroposterior and caudal views for both ipsilateral and contralateral sides to the occluded site (TI-APi, TI-APc, TI-CAUi, and TI-CAUc, respectively) using magnetic resonance angiography (MRA) or computed tomography angiography (CTA). We defined the first-pass effect (FPE) as first-pass mTICI classification ≥2b reperfusion. RESULTS: Patients who did not achieve FPE had significantly higher TI-APi (112 vs. 106; P = 0.004), TI-APc (111 vs. 105; P = 0.005), TI-CAUi (110 vs. 105; P = 0.002), and TI-CAUc (110 vs. 105; P = 0.001) than those who achieved FPE. In multivariable analysis, higher TI-APi, TI-CAUi, and TI-APc were independently associated with an increased rate of unsuccessful FPE (odds ratio (OR) [95% confidence interval (CI)]: 1.25 [1.02-1.61], 1.21 [1.01-1.45], and 1.27 [1.03-1.73], respectively). TI-CAUi, TI-APc, and TI-CAUc were also independent predictors of the occurrence of intracranial hemorrhage after MT (OR [95% CI]: 1.15 [1.01-1.38], 1.14 [1.01-1.38], 1.25 [1.02-1.52], respectively). CONCLUSIONS: The TIs of the MCA M1 segment on both ipsilateral and contralateral sides were associated with unfavourable outcomes after MT.

Umbilical vessel catheter retro-exchange technique (U-RET) for repeat use of the umbilical artery for neonatal vascular intervention: Technical note.

A high flow arteriovenous shunts in newborns may require urgent endovascular treatment right immediately after delivery if high output cardiac failure is resistant to medical treatment. The umbilical approach is often the first choice of the access route for endovascular treatment in the newborn. It is, however, not infrequent that the patient has an extensive lesion, which necessitates a second session of treatment because of the limitation of the usable amount of the contrast material in one session. In such a case, re-puncturing the femoral artery is difficult and carries the risk of leg ischemia. On the other hand, leaving the umbilical sheath for the second procedure carries risks of infection, thrombosis, and vessel injury. Herein we introduce our umbilical vessel catheter (UVC) retro-exchange technique (U-RET) in which we replace the umbilical sheath to a 3.5Fr UVC at the end of the first endovascular procedure to preserve the umbilical artery access and prepare for the repeated use. We believe that this method minimizes the risks of infection and vessel injury.

Angiographic classification of the inferior sagittal sinus based on the venous drainage patterns.

PURPOSE: The inferior sagittal sinus (ISS) and its tributaries have received little attention because of its inconspicuous appearance, and its anatomical variations are also unknown. This study aimed to evaluate the morphological variations of the ISS. MATERIALS AND METHODS: We retrospectively reviewed 518 patients in whom cerebral angiography was clinically indicated. The detailed angioarchitecture of the cerebral venous system, including the ISS and their tributaries, and the morphological variations of the ISS were evaluated. Abnormalities of the rostral third superior sagittal sinus (SSS) were also evaluated. RESULTS: The ISS was visualized in 270 (52.1%) patients. We proposed an angiographic ISS classification according to the venous drainage patterns: Type 0, not visualized; Type 1, small ISS with faint tributaries; Type 2, moderate ISS with developed tributaries; and Type 3: large ISS with well-developed tributaries, which are responsible for the venous drainage of the anterior frontal lobe. The frequency of each ISS type was as follows: Type 0, 248 (47.9%); Type 1, 211 (40.7%); Type 2, 44 (8.5%); and Type 3, 15 (2.9%). The mean ISS size was significantly larger with an increase in the type of ISS (p < 0.0001). The rostral third SSS hypoplasia was observed in all cases of Type 3. The hypoplasia of the rostral third SSS and development of the ISS were strongly correlated and complementary to each other. CONCLUSION: This study provided the angiographic ISS classification, and our proposed angiographic ISS classification could be helpful in better understanding of the ISS anatomy and its venous drainage pattern.

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.