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.

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.

A case of primary small cell neuroendocrine carcinoma of the uterus.

Neuroendocrine carcinoma of the uterine endometrium is extremely rare and found in <1% of all primary endometrial carcinomas. We report a case of neuroendocrine carcinoma of the endometrium detected in a 65-year-old woman and focus our attention on the main imaging features. The low apparent diffusion coefficient value and high maximum standardized uptake value for neuroendocrine cancer serve to distinguish this cancer from endometrial cancer.

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.

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.

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.