Transarterial Embolization of Renal Arteriovenous Malformations: Treatment Outcomes According to Angiographic Classification.

PURPOSE: To assess the different adjunctive catheter techniques required to achieve complete occlusion of renal arteriovenous malformations (rAVMs) of different angioarchitectural types. MATERIALS AND METHODS: Overall, data on 18 patients with rAVM (Type 1, n = 7; Type 2, n = 2; Type 3, n = 9; mean age, 53.8 years) who underwent 25 procedures between 2011 and 2022 were reviewed. The clinical presentations, endovascular techniques, arteriovenous malformation (AVM) occlusion rate, adverse events (including the incidence of renal infarction), and clinical symptoms and outcomes (including recurrence/increase of AVM) were analyzed according to the Cho-Do angioarchitectural classification. Posttreatment renal infarction was classified as no infarction, small infarction (<12.5%), medium infarction (12.5%-25%), and large infarction (>25%) using contrast-enhanced computed tomography or magnetic resonance imaging. RESULTS: Hematuria and heart failure were presenting symptoms in 10 and 2 patients, respectively. The embolic materials used were as follows: Type 1 rAVM, coils alone or with n-butyl-2-cyanoacrylate (nBCA); Type 2 rAVM, nBCA alone or with coils; and Type 3 rAVMs, nBCA alone. Fourteen patients underwent adjunctive catheter techniques, including flow control with a balloon catheter and multiple microcatheter placement, alone or in combination. Immediate postprocedural angiography revealed complete occlusion in 15 patients (83%) and marked regression of rAVM in 3 (17%). Small asymptomatic renal infarctions were observed in 6 patients with Type 3 rAVMs without any decrease in renal function. No major adverse events were observed. All symptomatic patients experienced symptom resolution. Recurrence/increase of rAVM was not observed during the mean 32-month follow-up period (range, 2-120 months). CONCLUSIONS: Transarterial embolization using adjunctive catheter techniques according to angioarchitectural types can be an effective treatment for rAVMs.

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.

Utility of a Steerable Microcatheter for the Selective Transvenous Embolization of Dural Arteriovenous Fistulas.

Objective: Selective transvenous embolization (sTVE) is an effective technique for treating dural arteriovenous fistulas (DAVFs); however, selective catheterization into the shunted pouch is often difficult due to the acute angle of the access route between the target pouch and dural sinus. We present our initial experience using a steerable microcatheter (SM) to manually control the tip angle for selective catheterization and sTVE of DAVFs. Methods: Thirteen consecutive cases of DAVFs and 16 procedures that involved sTVE using SM between October 2016 and October 2018 were reviewed. SMs were used for selective catheterization of shunted venous pouches and/or the affected sinus and coil embolization. We evaluated the maneuverability of the SM, the success of selective catheterization into the target lesions, and the results of endovascular treatments. Results: Endovascular procedures were performed in a single session in 10 cases and in two staged sessions in 3 cases. There was no difficulty in maneuverability of the SM. Successful selective catheterization was achieved in 26 of 27 target lesions. Immediately after embolization, angiography showed complete occlusion in 10 cases and marked reduction in 3 cases. During 40.9 months of mean follow-up, 12 cases showed complete occlusion and one case showed a small residual shunt on MRI. Procedure-related complications of spontaneous thrombosis of the affected sinus were observed in one case. There were no cases of recurrence or exacerbation during follow-up. Conclusion: SM is useful for selective catheterization for target lesions during sTVE of DAVFs.

A Case of Cavernous Sinus Dural Arteriovenous Fistula Draining Solely to the Superior Ophthalmic Vein with Normal Cerebral Venous Flow from the Superficial Middle Cerebral Vein to the Inferior Petrosal Sinus due to a Septum in the Cavernous Sinus.

Objective: We report here an atypical case of cavernous sinus dural arteriovenous fistula (CSDAVF) with a septation that separates the cavernous sinus (CS) into two components, namely, normal cerebral venous drainage and shunted blood drainage into the superior ophthalmic vein (SOV) alone. The CSDAVF was successfully treated by selective transvenous embolization (TVE) through the septum with the trans-inferior petrosal sinus (IPS) approach. Case Presentation: A 74-year-old woman presented with right exophthalmos and tinnitus on the right side. Neuroradiological examination showed CSDAVF mainly supplied by multiple feeders from the bilateral ascending pharyngeal artery and meningohypophyseal trunk with a shunted pouch located medial-dorsally to the right CS. Blood from the CSDAVF drained via the anterior component of the CS to the right SOV only. Normal cerebral venous blood from the right superficial middle cerebral vein drained through the dorsolateral component of the right CS into the right IPS. These findings suggest that a septal barrier exists between the outflow tract of the dural arteriovenous fistula and the normal cerebral venous outflow tract within the CS. The CSDAVF was successfully treated by selective TVE through the septum with the trans-IPS approach after detailed evaluation of 3D rotational angiography (3DRA) and MRA/MR venography (MRV) cross-sectional images. The patient's symptoms improved, and she was discharged uneventfully. Conclusion: Septation within the CS can completely separate the drainage route of the CSDAVF from the normal cerebral drainage route. Successful catheterization to the shunted pouch through the septum with the IPS approach and selective embolization were possible with detailed evaluation of anatomy on MRA/MRV cross-sectional images and 3DRA images.

Selective transarterial embolization for arterial hemorrhage after upper third molar extraction: illustrative cases.

BACKGROUND: The present report describes 2 cases of arterial bleeding after removal of the upper third molar that were successfully treated with selective transarterial embolization. OBSERVATIONS: The first patient underwent removal of the left upper third molar. A few hours later, facial swelling and massive bleeding appeared near the extraction socket involving the posterolateral wall of the maxillary sinus. Angiography showed a pseudoaneurysm involving the posterior superior dental artery, and the lesion was selectively embolized with an N-butyl cyanoacrylate (NBCA)-lipidiol mixture. The second patient underwent removal of the left upper third molar, and massive bleeding occurred from the extraction socket involving the greater palatine foramen. Angiography revealed the pseudoaneurysm of the greater palatine artery, and the lesion was selectively embolized with an NBCA-lipiodol mixture. Both patients were discharged uneventfully, and no recurrent bleeding was observed during the 82- and 5-month follow-up periods. LESSONS: Massive arterial bleeding after a third molar extraction occurs from either the posterior superior dental artery or the greater palatine artery, which is associated with the location of the extraction socket. Selective transarterial glue embolization is a useful option for the treatment of arterial bleeding after the removal of the upper third molars.

[Brain Arteriovenous Malformations:Indications and Treatment Results of Endovascular Embolization].

Brain arteriovenous malformations(BAVMs)are rare, but have a risk of serious intracranial hemorrhage in young adults. Endovascular treatment(EVT)has an important role in BAVM management with various purposes, including preoperative devascularization, volume reduction before stereotactic radiotherapy, curative embolization, and palliative embolization. In this article, the author reviews recent studies on EVT and relevant studies on BAVM management. Although no definitive evidences of utilizing EVT have been provided because of the various EVT outcomes depending upon various angioarchitectures, treatment goals, strategies, and physician's skills, EVT is certainly useful in selected cases. The role of EVT in BAVM management should be tailored to each patient while weighing the relative risks and benefits.

Spinal intraosseous arteriovenous fistulas with perimedullary drainage associated with vertebral compression fracture: illustrative case.

BACKGROUND: Although osseous involvement is occasionally observed in spinal epidural arteriovenous fistulas (AVFs) or seen as a part of diseases of spinal arteriovenous metameric syndrome, purely intraosseous spinal AVFs are extremely rare. Their clinical and imaging characteristic features are not well known. The authors present a case of purely intraosseous AVFs associated with compression fracture. OBSERVATIONS: A 76-year-old man presented with back pain and progressive myelopathy. Computed tomography showed compression fracture of the T12 vertebral body and dilatation of perimedullary veins. Spinal angiography revealed an intraosseous AVF at the T12 spine level, which was fed by multiple feeders of ventral somatic branches and drained into the paravertebral and perimedullary veins. The intraosseous AVF was completely occluded by the combined techniques of transarterial and transvenous embolization with glue and a coil. The symptoms disappeared within 1 month after embolization. LESSONS: Although extremely rare, spinal intraosseous AVFs can develop after compression fracture and cause congestive myelopathy. Combined transarterial and transvenous embolization is useful for the specific case of spinal intraosseous AVFs with both paravertebral and perimedullary drainage.

High D-Dimer Concentration Is a Significant Independent Prognostic Factor in Patients with Acute Large Vessel Occlusion Undergoing Endovascular Thrombectomy.

OBJECTIVE: To investigate prognostic factors that affect the modified Rankin Scale score at 3 months after onset of acute stroke in patients with large vessel occlusion who underwent endovascular thrombectomy. METHODS: We retrospectively examined 87 consecutive patients who underwent endovascular cerebral thrombectomy for acute anterior circulation large vessel occlusion at Oita University Hospital and Nagatomi Neurosurgery Hospital from January 2014 to December 2020. RESULTS: Age, National Institutes of Health Stroke Scale score, and D-dimer concentration on admission were significant univariate prognostic factors related to modified Rankin Scale score at 3 months after stroke onset. Multivariate logistic regression analysis showed that D-dimer concentration was the only significant independent prognostic factor. The area under the receiver operating characteristic curve for D-dimer concentration and modified Rankin Scale score at 3 months was 0.715 (95% confidence interval 0.599-0.831); sensitivity and specificity were 60.6% and 80.0%, respectively, using a 1.9 µg/mL cutoff value. CONCLUSIONS: Prognosis may be worse in patients undergoing acute endovascular cerebral thrombectomy with high D-dimer concentration on admission. Other treatment options should be considered for these patients.

Selective transvenous embolization combined with balloon angioplasty of the occluded inferior petrosal sinus for the treatment of cavernous sinus dural arteriovenous fistulas.

BACKGROUND AND PURPOSE: Angioplasty of the dural sinus has rarely been performed for the treatment of cavernous sinus dural arteriovenous fistulas. We evaluated the efficacy of selective transvenous embolization (TVE) combined with balloon angioplasty of the occluded inferior petrosal sinus (IPS) for the treatment of cavernous sinus dural arteriovenous fistulas (CSDAVFs). MATERIALS AND METHODS: A total of 8 consecutive patients with CSDAVFs with occlusion of the IPS treated by selective TVE with balloon angioplasty of the IPS from July 2018 to January 2019 were retrospectively reviewed. There were 6 females and 2 males with an average age of 77.6 years. All patients showed ocular symptoms. Angiography showed cortical venous reflux in 7 cases and localized shunted pouches at the medial portion of the cavernous sinus, intercavernous sinus, or laterocavernous sinus. Selective TVE was performed via the occluded IPS with bilateral femoral venous approaches, and the occluded IPS was reconstructed by angioplasty with a 2- to 3-mm diameter balloon during or after selective TVE. RESULTS: CSDAVFs disappeared immediately after treatment, and the occluded IPSs were successfully reconstructed with re-establishment of normal antegrade venous flow in all cases. No complications were observed, and symptoms resolved within 2 weeks after treatment. During the 7-month mean follow-up period (range 1-12 months), no cases showed recurrence of CSDAVFs. CONCLUSION: Selective TVE combined with balloon angioplasty of the occluded IPS is safe and effective for the treatment of CSDAVFs and re-establishes normal venous circulation in selected cases with localized shunted pouches.

Angiographic features and transarterial embolization of retained placenta with abnormal vaginal bleeding.

OBJECTIVES: To clarify characteristic angiographic features and clinical efficacy of selective transarterial embolization (TAE) of retained placenta with abnormal vaginal bleeding. METHODS: The study cohort comprised 22 patients (mean age, 33.5 years; range, 22-24 years) who underwent selective TAE for retained placenta with abnormal bleeding between January 2018 and December 2020 at our institution. Angiographic images were reviewed by two certified radiologists with consensus. Medical records were reviewed to evaluate the efficacy of TAE. Angiographic features of retained placenta, technical success (disappearance of abnormal findings on angiography), complications, clinical outcomes (hemostatic effects and recurrent bleeding) were evaluated. RESULTS: Pelvic angiography showed a dilated vascular channel mimicking arteriovenous fistulas or an aneurysm contiguous with dilated uterine arteries in the mid-arterial-capillary phase in 20 patients; it showed contrast brush in the remaining two patients. TAE technical success was achieved in all patients. No major complications were observed in any patients. Fifteen patients were followed up with expectant management after TAE; all but one patient showed no re-bleeding during the follow-up period (mean follow-up interval, 3.4 months; range, 1-17 months). One patient showed minor rebleeding, which resolved spontaneously. Seven patients underwent scheduled hysteroscopic resection within 1 week after TAE, and no excessive bleeding was observed during or after the surgical procedure in all seven patients. CONCLUSIONS: The characteristic angiographic feature of retained placenta is "dilated vascular channel that mimic low flow AVM." TAE is a safe and effective treatment to manage retained placenta with abnormal bleeding.

Fenestration of the cavernous internal carotid artery associated with a persistent primitive trigeminal artery.

Fenestration of the cavernous segment of the internal carotid artery (ICA) is an extremely rare variant with unknown clinical significance. We present two cases of this variant, both of which were associated with a persistent primitive trigeminal artery (PPTA). Large dual channels of the ICA were seen extending from the part immediately distal to the origin of the PPTA to the C3 segment of the ICA. We speculate that coexistence of the two vascular anomalies might be due to failed regression or a remnant of the primitive arterial network during the same early gestation period in which development of the PTA takes place (3-5 mm crown-rump length stage).

Vessel Occlusion using Hydrogel-Coated versus Nonhydrogel Embolization Coils in Peripheral Arterial Applications: A Prospective, Multicenter, Randomized Trial.

PURPOSE: To evaluate the safety and effectiveness of hydrogel-coated coils for vessel occlusion in the body trunk. MATERIALS AND METHODS: A total of 77 patients with various peripheral vascular lesions, treatable by embolization with coils, were randomized (hydrogel group, n = 38; nonhydrogel group, n = 39). In the hydrogel group, embolization of the target vessel was conducted using 0.018-inch hydrogel-coated coils (AZUR 18; Terumo Medical Corporation, Tokyo, Japan) with or without bare platinum coils. The nonhydrogel group received both bare platinum coils and fibered coils without the use of hydrogel-coated coils. RESULTS: Complete target vessel occlusion was accomplished in 36 patients in the hydrogel group and 37 patients in the nonhydrogel group. No major adverse events were observed in either group. The median number of coils/vessel diameter and the median total coil length/vessel diameter were significantly larger in the nonhydrogel group than in the hydrogel group (P = .005 and P = .004, respectively). The median embolization length was significantly longer in the nonhydrogel group (31.95 mm) than in the hydrogel group (23.43 mm) (P = .002). If no expansion was assumed, the median packing density in the hydrogel group was 44.9%, which was similar to that in the nonhydrogel group (46.5%) (P = .79). With full expansion assumed, the median packing density in the hydrogel group was 125.7%. CONCLUSIONS: Hydrogel-coated coils can be safely used for peripheral vascular coil embolization, and hydrogel-coated and conventional coils in combination allow for a shorter embolization segment and shorter coil length.

[Dural Arteriovenous Fistula].

Dural arteriovenous fistulas(dAVFs), which are arteriovenous shunts between the dural/epidural artery and dural vein and/or dural venous sinus, can cause various symptoms, and the risk of aggressive symptoms such as cerebral hemorrhage and venous infarction mainly depends on venous drainage patterns in patients. Patients with dAVFs with cortical venous reflux have a high risk of aggressive symptoms due to cerebral venous congestion or varix rupture, and they often develop brain edema and/or hemorrhage. In some cases, patients with dAVFs may have CT and MRI findings similar to those of patients with brain tumors. Key MRI findings suggesting dAVFs include multiple small flow voids representing cortical venous reflux adjacent to the hemorrhage or edematous lesion on T2WI and dot-like high-signal-intensity patterns of the feeding arteries and draining veins on time-of-flight MR angiography source images. Cerebral angiography should be performed quickly when dAVFs are suspected with careful assessment using CT/MRI to prevent further worsening of symptoms, particularly for lesions involving the brain stem and cerebellum.

Location of embolization affects patency after coil embolization for pulmonary arteriovenous malformations: importance of time-resolved magnetic resonance angiography for diagnosis of patency.

OBJECTIVES: This study aimed to assess the diagnostic accuracy of computed tomography (CT) and time-resolved magnetic resonance angiography (TR-MRA) for patency after coil embolization of pulmonary arteriovenous malformations (PAVMs) and identify factors affecting patency. METHODS: Data from the records of 205 patients with 378 untreated PAVMs were retrospectively analyzed. Differences in proportional reduction of the sac or draining vein on CT between occluded and patent PAVMs were examined, and receiver operating characteristic analysis was performed to assess the accuracy of CT using digital subtraction angiography (DSA) as the definitive diagnostic modality. The accuracy of TR-MRA was also assessed in comparison to DSA. Potential factors affecting patency, including sex, age, number of PAVMs, location of PAVMs, type of PAVM, and location of embolization, were evaluated. RESULTS: The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of CT were 82%, 81%, 77%, 85%, and 82%, respectively, when the reduction rate threshold was set to 55%, which led to the highest diagnostic accuracy. The sensitivity, specificity, PPV, NPV, and accuracy of TR-MRA were 89%, 95%, 89%, 95%, and 93%, respectively. On both univariable and multivariable analyses, embolization of the distal position to the last normal branch of the pulmonary artery was a factor that significantly affected the prevention of patency. CONCLUSIONS: TR-MRA appears to be an appropriate method for follow-up examinations due to its high accuracy for the diagnosis of patency after coil embolization of PAVMs. The location of embolization is a factor affecting patency. KEY POINTS: • Diagnosis of patency after coil embolization for pulmonary arteriovenous malformations (PAVMs) is important because a patent PAVM can lead to neurologic complications. • The diagnostic accuracies of CT with a cutoff value of 55% and TR-MRA were 82% and 93%, respectively. • The positioning of the coils relative to the sac and the last normal branch of the artery was significant for preventing PAVM patency.

Delineability and anatomical variations of perforating arteries from normal vertebral artery on 3D DSA: implications for endovascular treatment of dissecting aneurysms.

BACKGROUND AND PURPOSE: Endovascular trapping of the vertebral artery dissecting aneurysms (VADAs) carries a risk of medullary infarction due to the occlusion of the perforating arteries. We evaluated the detectability and anatomical variations of perforating arteries arising from the vertebral artery (VA) using three-dimensional DSA. METHODS: In 120 patients without VA lesions who underwent rotational vertebral arteriography, the anatomical configurations of perforating arteries from the VA were retrospectively evaluated on the bi-plane DSA and reconstructed images to reach the consensus between two experienced reviewers. The images were interpreted by focusing on the numbers and types of perforating arteries, the relationships between the number of perforators and the anatomy of the VA and its branches. RESULTS: Zero, 1, 2, 3, 4, and 6 perforators were detected in 2, 51, 56, 9, 1, and 1 patient, respectively (median of 2 perforators per VA). The 200 perforators were classified into 146 terminal and 54 longitudinal course types and into 32 ventral, 151 lateral, and 17 dorsolateral distribution types. All ventral type perforators were also terminal type. In contrast, the longitudinal type was seen in 28.5% of lateral types and in 65% of dorsolateral types. Regarding the difference in the origin of the posterior inferior cerebellar artery (PICA), non-PICA type VAs gave off larger number of perforators than the other types of VAs. CONCLUSIONS: Non-PICA type VAs give off a significantly larger number of perforators than other types, indicating that the trapping of non-PICA type VAs is associated with a risk of ischemic complications.

Risk factors for medullary infarction after endovascular trapping of vertebral artery dissecting aneurysms.

Internal trapping (IT) is a treatment option for intracranial vertebral artery dissecting aneurysms (VADAs). Medullary infarction (MI) is a complication linked to this treatment. This study aims to clarify the outcomes of IT for VADAs and the risk factors for MIs. We retrospectively reviewed the databases from 2010 to 2017 to identify patients with VADAs treated by IT at seven collaborating institutions. Radiological findings, clinical courses, and outcomes were analyzed. Perforating arteries were classified into terminal or longitudinal types using preoperative angiography. IT was completed in 90 patients (74 ruptured and 16 unruptured VADA). Postoperative rebleeding did not occur in any ruptured VADA patients. Postoperative MRI detected MIs in 26 patients (28.9%). The incidence of MIs in the ruptured VADA (32%) was higher compared with that in the unruptured VADA (13%), though it was not significant. In the MI group, the occlusion or blind alley of the terminal-type and longitudinal-type perforator was confirmed in 23 patients (88%) and 11 patients (42%), respectively. The occlusion or blind alley of the terminal-type perforator was an independent risk factor for MIs in the logistic regression analysis (OR 5.81; 95% CI 1.34-25.11; p = 0.018). In ruptured VADA, postoperative MI (OR 12.2; 95% CI 3.19-64.55; p = 0.0001) and high-grade SAH (OR 8.02; 95% CI 2.32-37.70; p = 0.0006) were independent risk factors of an unfavorable clinical outcome. In conclusion, MIs were an independent risk factor for unfavorable outcomes after IT, especially for a ruptured VADA. The occlusion or blind alley of the terminal-type perforator caused by the IT was associated with postoperative MIs.

Transarterial Embolization of a Parasellar Hypervascular Tumor.

Embolization of hypervascular tumors has been widely performed for over four decades, particularly for preoperative meningioma. Several benefits of preoperative embolization have been reported, including reduced blood loss, surgical time and surgical complications, and improved outcomes. However, the technical details of both embolization and surgical procedures, and lesions widely vary. Thus, the actual benefits of preoperative embolization have not been clarified by prospective randomized studies. Procedure-related complications due to embolization developed in 3%-12% in previous studies. For parasellar lesions, both surgical resection and embolization have a higher risk of complication than for lesions at other locations because of the complicated neurovascular anatomy in the parasellar area. Therefore, close attention should be paid to the detailed vascular anatomy, embolic material, and related information for embolization and resection in individual cases to improve patient outcomes.

Direct Carotid Cavernous Fistulas.

A direct carotid cavernous fistula (CCF) is an abnormal shunt between the internal carotid artery (ICA) and the cavernous sinus (CS). Traumatic CCF is the most common type, accounting for up to 75% of all CCFs. For the management of direct CCF, endovascular therapy has become the standard. For successful endovascular therapy, evaluation of the size and location of orifice of the CCF, venous drainage, and tolerance for ICA occlusion on cerebral angiography is necessary. Multi-planner reformatted images of 3D rotation angiography are useful to visualize the fistula and compartments of the CS precisely. Due to the limited commercial availability of detachable balloons, detachable coils have become a widely employed endovascular tool for the treatment of direct CCFs. The advantageous aspects of coil application are their easy retrievability and better control. In the case of large/multiple fistulas, adjunctive techniques, including balloon- and stent-assisted techniques, are often needed to occlude the CCF while preserving the ICA. To avoid cranial nerve palsy related to over-packing of the CS with detachable coils or a detachable balloon, selective embolization of the fistula portion is required. Use of liquid embolic materials and covered stents was recently reported as another adjunctive technique. In cases in which it is impossible to occlude the CCF while preserving the ICA, parent artery occlusion (PAO) is considered. The selection of additional/alternative techniques and devices depends on the anatomy and hemodynamics of each CCF, and the skill and experience of individual operators.

Diploic arteriovenous fistulas with marked cortical venous reflux.

Diploic arteriovenous fistulas are rare arteriovenous shunts involving the skull, which often drain antegradely into the internal or external jugular veins. Diploic arteriovenous fistulas with marked cortical venous reflux are extremely rare. Here, we present the case of a patient with diploic arteriovenous fistulas with marked cortical venous reflux and a literature review. A 73-year-old woman presented with headache. Magnetic resonance angiography revealed abnormal signal intensity in the diploic layer of the left frontal bone. Digital subtraction angiography demonstrated a diploic arteriovenous fistulas located in the left frontal bone. The arteriovenous fistulas were fed by multiple branches of the left external carotid artery, mainly from the middle meningeal artery, branches of the ophthalmic artery, and the inferolateral trunk. The fistulas drained into the cerebral cortical veins surrounding the frontal lobe via an emissary vein of the frontal bone. With the femoral arterial approach, transarterial catheterization into the shunted diploic vein was performed with a small tapered microcatheter, and the arteriovenous fistulas were completely embolized with N-butyl-2-cyanoacrylate. The patient was discharged without complications. No recurrent arteriovenous fistulas were observed during the 12-month follow-up period. Endovascular treatment is an effective technique for the curative treatment of diploic arteriovenous fistulas.

Correction To: Where is the Origin of the Last Normal Branch from Feeding Artery of Pulmonary Arteriovenous Malformations?

On page 1852, the first sentence of the second paragraph "In all PAVMs, the mean diameter of the feeding artery was 7.24 ± 0.015 mm, and the mean maximum diameter of the sac was 19.10 ± 0.585 mm" should be corrected to read as follows.