Mika Okahara

Diagnostic accuracy of magnetic resonance angiography for cerebral aneurysms in correlation with 3D-digital subtraction angiographic images: a study of 133 aneurysms.

Background and Purpose— We investigated the sensitivity of 3D–time-of flight (3D-TOF) magnetic resonance angiography (MRA) in the detection of cerebral aneurysms with the use of 3D digital subtraction angiography as the gold standard. We also evaluated the effects of location and number of aneurysms (and experience of the reader) on the sensitivity. Methods— 3D-TOF MRA was performed in 82 patients with 133 cerebral aneurysms. Each patient underwent rotational angiography. Three-dimensional reconstructed images were obtained from data of the rotational angiography (as the gold standard). A blind study with 4 readers of different experiences was performed to evaluate the diagnostic accuracy of 3D-TOF MRA for cerebral aneurysms. Results— One hundred five (79%) of all 133 aneurysms were detected with MRA by a neuroradiologist, 100 (75%) were detected by an experienced neurosurgeon, 84 (63%) were detected by a general radiologist, and 80 (60%) were detected by a resident neuroradiologist. For each reader, the detectability was lower for small aneurysms (<3 mm in maximum diameter) and/or for those located at the internal carotid artery and anterior cerebral artery. False-positive aneurysms were 29 for the neuroradiologist, 19 for the neurosurgeon, 31 for the general radiologist, and 30 for the resident neuroradiologist; most of the aneurysms were at the internal carotid artery. Causes of the false-positive and false-negative results included complex flow in a tortuous artery and susceptibility artifacts. Conclusions— Although MRA is useful in the diagnosis of cerebral aneurysms, sufficient experience and careful attention are necessary for accurate diagnosis of aneurysms located at the internal carotid and anterior cerebral arteries.

Parotid tumors: MR imaging with pathological correlation

Most parotid tumors grow slowly, whether benign or malignant; thus, it is difficult to predict the malignant or benign nature of a tumor clinically. Magnetic resonance imaging may have a place in the diagnostic work-up of parotid tumors. The purpose of this article is to illustrate the MR imaging findings of parotid tumors and to correlate them to pathologic findings. The MR imaging may be helpful in differentiation of benign and malignant tumors of the parotid gland, and can provide important clues in the diagnosis of their histologies.

Treatment of mandibular arteriovenous malformation by transvenous embolization: A case report.

Arteriovenous malformations (AVMs) of the mandible are relatively rare and potentially life‐threatening lesions. Treatment is usually difficult. This study presents a case with high‐flow AVM of the mandible in which most of the AVM were occluded by transvenous coil embolization.

Endovascular recanalization of acute intracranial vertebrobasilar artery occlusion using local fibrinolysis and additional balloon angioplasty

IntroductionVertebrobasilar artery occlusion (VBO) produces high mortality and morbidity due to low recanalization rate utilization in endovascular therapy. The use of percutaneous transluminal angioplasty (PTA) to improve recanalization rate additional to local intra-arterial fibrinolysis (LIF) was investigated in this study. Results obtained following recanalization therapy in acute intracranial VBO are reported.MethodsEighteen consecutive patients with acute VBO underwent LIF with or without PTA, from August 2000 to May 2006. Eight patients were treated using LIF alone, and ten required additional PTA. Rate of recanalization, neurological status before treatment, and clinical outcomes were evaluated.ResultsOf 18 patients, 17 achieved recanalization. One procedure-related complication of subarachnoid hemorrhage occurred. Overall survival rate was 94.4% at discharge. Seven patients achieved good outcomes [modified Rankin scale (mRS) 0–2], and the other 11 had poor outcomes (mRS 3–6). Five of six patients who scored 9–14 on the Glasgow Coma Scale (GCS) before treatment displayed good outcomes, whereas ten of 12 patients who scored 3–8 on the GCS showed poor outcomes. GCS prior to treatment showed a statistically significant correlation to outcomes (p < 0.05). Moreover, the National Institutes of Health Stroke Scale (NIHSS) before treatment correlated well with mRS (correlation coefficient 0.487). No statistical difference between the good and poor outcome groups was observed for the duration of symptoms, age, etiology, and occlusion site.ConclusionsEndovascular recanalization can reduce mortality and morbidity of acute VBO. Good GCS and NIHSS scores prior to treatment can predict the efficacy of endovascular recanalization.

The anterior medullary-anterior pontomesencephalic venous system and its bridging veins communicating to the dural sinuses: normal anatomy and drainage routes from dural arteriovenous fistulas

IntroductionWe evaluated the normal venous anatomy of the anterior medullary/anterior pontomesencephalic venous (AMV/APMV) system and bridging veins connected to the dural sinuses using magnetic resonance (MR) imaging and demonstrated cases of dural arteriovenous fistulas (DAVFs) with bridging venous drainage.Materials and methodsMR images obtained using a 3D gradient echo sequence in 70 patients without lesions affecting the deep or posterior venous channels were reviewed to evaluate the normal anatomy of the AMV/APMV system and bridging veins. MR images and digital subtraction angiography in 80 cases with intracranial or craniocervical junction DAVFs were reviewed to evaluate the bridging venous drainage from DAVFs.ResultsMR images clearly revealed AMV/APMV in 35 cases. Fifteen cases showed a direct connection between AMV and APMV, while 15 cases showed an indirect communication via the transverse pontine vein or the bridging vein. In the five remaining cases, the AMV and APMV end separately to the bridging vein or the transverse pontine vein. Bridging veins were identified in 34 cases, connecting to the cavernous sinus in 33, to the suboccipital cavernous sinus in 11, and the inferior petrosal sinus in five cases. In 80 DAVF cases, seven of 40 cavernous sinus DAVFs, two craniocervical junction DAVFs, and one inferior petrosal sinus DAVF drained via bridging veins to the brain stem.ConclusionThe AMV/APMV and bridging veins showed various anatomies and frequently showed a connection to the cavernous sinus. Knowledge of the venous anatomy is helpful for the diagnosis and intravascular treatment of DAVFs.

Dural Arteriovenous Fistula Involving the Posterior Condylar Canal

SUMMARY: Although dural arteriovenous fistulas (DAVFs) occur in any structure that is covered by the dura mater, DAVFs at the posterior condylar canal have not been reported. We present a DAVF that involves the posterior condylar canal and drains into the posterior condylar vein and the occipital sinus, which was treated by selective transvenous embolization. Knowledge of venous anatomy of the craniocervical junction and careful assessment of the location of the arteriovenous fistula can contribute to successful treatment.

Selective Transvenous Embolization of Dural Arteriovenous Fistulas Involving the Hypoglossal Canal

The hypoglossal canal contains a venous plexus that connects the inferior petrous sinus, condylar vein, jugular vein and paravertebral plexus. The venous plexus is one of the venous drainage routes of the posterior skull base. Only a few cases of dural arteriovenous fistulas (AVFs) involving the hypoglossal canal have been reported. We describe three cases (a 62-year-old female, a 52-year-old male, and an 83-year-old male) of dural AVFs involving the hypoglossal canal. Symptoms were pulse-synchronous bruit in two cases and proptosis/chemosis in one. All dural AVFs were mainly fed by the ipsilateral ascending pharyngeal artery. Two of three dural AVFs involving the hypoglossal canal mainly drained through the anterior condylar confluence into the inferior petrosal sinus retrogradely with antegrade drainage through the lateral condylar vein. The other one drained through the lateral and posterior condylar veins into the suboccipital cavernous sinus. All dural AVFs were completely occluded by selective transvenous embolization without any complications, and the symptoms disappeared within one week in all cases. Dural AVFs involving the hypoglossal canal can be successfully treated by selective transvenous embolization with critical evaluation of venous anatomy in each case.

Arterial supply to the pancreas; variations and cross-sectional anatomy

The pancreas has complex arterial supplies. Therefore, special attention should be paid in pancreatic arterial intervention for patients with acute pancreatitis and pancreatic carcinomas. Knowledge of pancreatic arterial anatomy and arterial territory is important not only to perform pancreatic arterial intervention, but to read the pancreatic angiography and cross-sectional image. We reviewed 226 selective abdominal angiography and CT scans during selective arteriography (CTA) of common hepatic artery, superior mesenteric artery, splenic artery, or peripancreatic arteries including posterior superior pancreaticoduodenal artery, anterior superior pancreaticoduodenal artery, inferior pancreaticoduodenal artery, and dorsal pancreatic artery. CTA images were evaluated to clarify the cross-sectional anatomy of the pancreatic arterial territory. Variations of the peripancreatic arteries were also investigated. In this exhibit, schemes and illustrative cases demonstrate pancreatic arterial territory and variations.

Transportal Intravariceal Sclerotherapy with N-Butyl-2-Cyanoacrylate for Gastric Varices

Four patients with gastric varices without catheterizable draining veins through a systemic vein were treated with transportal intravariceal sclerotherapy with n-butyl-2-cyanoacrylate (NBCA). In all patients, the gastric varices were successfully obliterated with 2-5 mL of NBCA-lipiodol mixture injected via a microcatheter introduced into the varices with transhepatic or transileocolic portal venous access. No complications related to the procedure were encountered. Follow-up gastroendoscopy showed disappearance (n = 3) or marked decrease (n = 1) of the varices. Neither recurrent gastric varices nor variceal bleeding were observed during the follow-up period (6-46 months). Transportal intravariceal sclerotherapy is useful for obliteration of gastric varices in selected cases.

Development of a New Coaxial Balloon Catheter System for Balloon-Occluded Retrograde Transvenous Obliteration (B-RTO)

PurposeTo develop a new coaxial balloon catheter system and evaluate its clinical feasibility for balloon-occluded retrograde transvenous obliteration (B-RTO).MethodsA coaxial balloon catheter system was constructed with 9 Fr guiding balloon catheter and 5 Fr balloon catheter. A 5 Fr catheter has a high flexibility and can be coaxially inserted into the guiding catheter in advance. The catheter balloons are made of natural rubber and can be inflated to 2 cm (guiding) and 1 cm (5 Fr) maximum diameter. Between July 2003 and April 2005, 8 consecutive patients (6 men, 2 women; age range 33–72 years, mean age 55.5 years) underwent B-RTO using the balloon catheter system. Five percent ethanolamine oleate iopamidol (EOI) was used as sclerosing agent. The procedures, including maneuverability of the catheter, amount of injected sclerosing agent, necessity for coil embolization of collateral draining veins, and initial clinical results, were evaluated retrospectively. The occlusion rate was assessed by postcontrast CT within 2 weeks after B-RTO.ResultsThe balloon catheter could be advanced into the proximal potion of the gastrorenal shunt beyond the collateral draining vein in all cases. The amount of injected EOI ranged from 3 to 34 ml. Coil embolization of the collateral draining vein was required in 2 cases. Complete obliteration of gastric varices on initial follow-up CT was obtained in 7 cases. The remaining case required re-treatment that resulted in complete obstruction of the varices after the second B-RTO. No procedure-related complications were observed.ConclusionB-RTO using the new coaxial balloon catheter is feasible. Gastric varices can be treated more simply by using this catheter system.