An innovative technique for detecting the caudal end of occluded inferior petrosal sinus in cavernous arteriovenous fistula using intravascular ultrasonography--technical note.

INTRODUCTION: Although cavernous sinus (CS) dural arteriovenous fistulas (d-AVFs) are usually treated with transvenous embolization (TVE) via the inferior petrosal sinus (IPS), IPSs are sometimes thrombosed and angiographically invisible. In such cases, the first obstacle to TVE is detecting the entry to the IPS. We report a new technique for TVE via IPS using intravascular ultrasonography (IVUS). METHODS: Three consecutive cases of CS d-AVF with ipsilateral or bilateral IPS occlusion were involved in this study. On TVE, the orifice of the IPS was investigated with IVUS placed in the jugular vein or jugular bulb. RESULTS: This technique has been successfully adapted in all three cases. In two of these cases, IPS was well visualized with the help of IVUS, and TVE was successfully performed. CONCLUSION: To our knowledge, this is the first report to mention the usefulness of IVUS for detecting angiographically occult IPS.

Post-embolisation susceptibility changes in giant meningiomas: multiparametric histogram analysis using non-contrast-enhanced susceptibility-weighted PRESTO, diffusion-weighted and perfusion-weighted imaging.

PURPOSE: To investigate imaging characteristics of post-embolised meningioma and to determine if SW imaging can delineate tumour ischaemia. MATERIALS AND METHODS: Sixteen patients were studied before and after preoperative embolisation therapy (8 histopathologically determined with ischaemia, 8 with non-ischaemia). In each patient, a slice-wise ROI for the entire tumour was established, and histogram variables (mean, SD, minimum, maximum, histogram width, mode, and peak height) of SW, ADC, CBV, CBF, MTT, and TTP maps were compared between ischaemic and non-ischaemic groups. Changes in SW histogram were correlated with histopathological characteristics. RESULTS: Signal intensity on the SW map tended to decrease in the ischaemic group and partially increased in the non-ischaemic group. A similar trend was observed on the ADC map. The PW histogram showed an MTT increase in ischaemic group; however, CBV did not show significant changes between ischaemic and non-ischaemic groups. Microhaemorrhage was slightly correlated with Δpeak height in the SW histogram. CONCLUSION: Post-embolisation changes of intrinsic T2-weighted MR contrasts on SW map are most likely associated with alterations in deoxyhaemoglobin levels and arterial blood flow.

Diffuse-Type Tenosynovial Giant Cell Tumor Arising in the Temporomandibular Joint Extending to the External Auditory Canal: A Case Report and Literature Review.

A 74-year-old Japanese woman with a 1-year history of right preauricular pain and a 2-month history of bleeding from the right ear was admitted to our department. Tumor was observed in the anterior wall in the right external auditory canal. Bony swelling of the right preauricular area was palpated. Computed tomography revealed an ill-defined, osteogenic tumor around the mandibular condyle with a destructive bony lesion involving the temporal bone. Magnetic resonance imaging revealed a 2.0 × 1.5 × 1.3-cm solid tumor around the mandibular condyle, exhibiting a low-intensity signal on T1-weighted imaging and an isointense central area surrounded by low-signal intensity on T2-weighted imaging. Histological examination of biopsy specimens revealed diffuse-type tenosynovial giant cell tumor (D-TGCT). After the feeding arteries for the tumor were embolized, the patient underwent surgery with combined temporal craniotomy and mandibular condylectomy. The soft and cystic tumor with calcification located in the extradural space was totally resected along with the mandibular condyle. No facial paralysis or recurrence was evident as of 6 months postoperatively. To date, only 23 cases of D-TGCT arising in the temporomandibular joint (TMJ) with ear involvement have been reported since 2011. We report successful resection of a rare case of D-TGCT arising in the TMJ.

Vasospasm as a major complication after acute mechanical thrombectomy with stent retrievers.

OBJECTIVE: Mechanical thrombectomy using a stent retriever for acute large vessel occlusion is indispensable in stroke treatment, however, vasospasm may occur. The objective of this retrospective study was to investigate which cases are more likely to experience vasospasm after thrombectomy with stent retrievers. METHODS: We included 29 patients diagnosed with acute cardiogenic cerebral embolism who were treated with stent retrievers at our facility from December 2014 to December 2017. Atherothrombotic brain infarction cases were excluded because it was difficult to evaluate for vasospasms. Vasospasm was defined as reversible arterial narrowing of <80% of the normal vessel diameter after usage of the stent retriever. The age, sex, type of stent retriever, occlusion site, number of procedures, thrombolysis in cerebral infarction (TICI) grade, degree of vasospasm, intracranial hemorrhage by the procedure, and neurological outcomes were analyzed. RESULTS: Among the 29 cases, 12 (41.4%) resulted in vasospasm; nine cases were mild (20-50% stenosis) and 3 cases were severe (≥50% stenosis). Vasospasm frequently occurred in the distal part of the anterior circulation when compared to the proximal part. In addition, the frequency of vasospasm increased as the number of procedures increased. Pooled analysis showed significant difference in the intravenous tissue-type plasminogen activator group (P = 0.029). There was no significant difference in the other groups. CONCLUSION: Stent retrievers appear to cause vasospasm more than expected when including mild cases. Vasospasm tends to occur especially in cases with IV-tPA; prognosis is generally good, and it rarely requires any treatment.

Aberrant left subclavian artery occlusion in right-sided aortic artery associated with left cerebral infarction: A case report.

Purpose Right-sided aortic arch is a rare vessel anomaly with an incidence of 0.1% worldwide. Supra-aortic branches form a mirror image of the left-sided aortic arch or an aberrant left subclavian artery associated with Kommerell diverticulum. Most patients are diagnosed by a difference in blood pressure in each upper extremity or by the presence of left subclavian steal syndrome in their younger age. The diagnosis of onset of ischemic stroke in middle age is rare. Methods We present the case of a female patient who presented with an ischemic stroke in the left posterior circulation area. She had no history of congenital heart malformation. We performed head magnetic resonance imaging, cerebral angiography, and enhanced computed tomography of the aortic arch and major branches. Results The patient had a right-sided aortic arch and an aberrant left subclavian artery. The left subclavian artery was occluded at the proximal portion with a fibrous string. Collateral flow in the anterior cervical subcutaneous area supported left limb perfusion. Conclusion An atheromatous change reduced shunt flow via collateral networks at the anterior cervical region. Congenital subclavian steal supported the ischemic stroke.

Choroid plexus AVM with anomalous origin of the capsulothalamic artery: A case report.

Background and importance Traditionally, it has been believed that the plexal segment of the anterior choroidal artery (AChoA) can be sacrificed safely. Here, we present a case of choroid plexus arteriovenous malformation (AVM) in which the capsulothalamic artery originated from distal plexal segment of the AChoA. Clinical presentation A 45-year-old man was diagnosed with arteriovenous malformation involving the left inferior horn in screening MRI. Preceding stereotactic radiosurgery, transarterial target embolization was performed. In this procedure, 20% n-butyl-2-cyanoacrylate (NBCA) was successfully injected from the lateral plexal branch of the AChoA. After embolization, right homonymous hemianopsia developed due to cerebral infarction on the left optic radiation. This infarction was considered to be within the territory of the capsulothalamic artery. Conclusion This anomalous capsulothalamic artery might be formed by hemodynamic compromise of the brain surrounding AVM in early gestation. We must be aware of this unusual anatomical variation to avoid ischemic complication in embolization of the AChoA.

Usefulness of 18F-fluorodeoxyglucose-Positron Emission Tomography in Comparison with Methionine-Positron Emission Tomography in Differentiating Solid Hemangioblastoma from Adult Cerebellar Tumors.

BACKGROUND AND PURPOSE: Among adults with posterior fossa tumors, an intraaxial location of the tumor is less common than an extraaxial location. Moreover, the differential diagnosis of a single cerebellar tumor in adults is sometimes difficult by conventional magnetic resonance imaging. We aimed to report the findings of positron emission tomography (PET) using 18F-fluorodeoxyglucose (FDG) and methionine in adult patients with intraaxial and solitary metastatic brain tumors. MATERIALS AND METHODS: FDG-PET was performed on 12 patients with posterior fossa tumors: 4 had solid hemangioblastoma (HB), 3 had primary central nervous system lymphomas, 1 had a glioblastoma, and 4 had single metastatic brain tumors (METs). Methionine-PET was performed on 9 patients except for 1 patient with a MET. The maximum standardized uptake value (SUVmax) of the tumor was measured and compared with pathologic findings. RESULTS: The SUVmax of FDG in HB was lower compared with that of other tumors (P = 0.001). On the other hand, the SUVmax of methionine in the HB cases was almost the same as that in other tumors (P = 0.07). CONCLUSION: FDG-PET was helpful in differentiating HBs from adult cerebellar tumors.

Falcotentorial meningioma: surgical outcome in 14 patients.

OBJECT: The authors evaluated their surgical experience over 20 years with 14 treated falcotentorial meningiomas. METHODS: In the past 20 years, 14 patients with falcotentorial junction meningiomas were surgically treated. There were seven men and seven women, whose ages ranged from 34 to 79 years. On the basis of neuroimaging studies, the authors analyzed the influence of the anatomical relationship of the tumor to the vein of Galen, patency of the vein of Galen, tumor size, and the signal intensities on the magnetic resonance images to determine possible difficulties that might be encountered during surgery and to prognosticate the outcome of surgery. Depending on the relationship with the vein of Galen, tumors were labeled as either a superior or an inferior type. All tumors were resected via an occipital transtentorial approach. The surgical outcome in eight patients was excellent; in the remaining six patients, it was fair. Of the prognostic factors, tumor location especially seemed to be the most important (p < 0.01, Fisher exact test). The outcome associated with the inferior type of tumor was significantly less optimal probably due to the relationship to the deep veins and the brainstem. In this series, the occlusion of deep veins did not significantly influence outcome. CONCLUSIONS: . Classification of the tumor location by preoperative neuroimaging studies can be helpful in estimating the surgical difficulty that might be encountered in treating the falcotentorial junction meningioma.

Surgical management of petroclival chordomas: report of eight cases.

In the management of skull base chordomas, surgical treatment is essential to achieve long-term control. A petroclival chordoma growing laterally in the skull base is one of the most challenging tumors for neurosurgeons. We have treated petroclival chordomas based on the principle of maximal surgical resection of the tumor with minimal morbidity. Lateral skull base approaches were used to approach petroclival chordomas in eight patients. The surgical procedure involved removal of soft tumor tissue and extensive drilling of adjacent bony structures. Gross total resection of the tumor was achieved in six patients. Subtotal resection in the remaining two patients was associated with acceptable morbidity. In cases of petroclival chordomas, lateral skull base approaches can be used as a primary procedure, although those approaches may be associated with high rates of morbidity and mortality.

Histological characteristics of arterialized medullary vein in spinal dural arteriovenous fistulas related with clinical findings: report of five cases.

The histological features of arterialized medullary vein (MV) in spinal dural arteriovenous fistulas (SDAVF) were studied in five consecutive patients who presented with progressive congestive myelopathy. Retrograde venous filling on preoperative angiography was recognized as being severe in 3 cases and moderate in 2 cases. Direct intradural interruption of the arterialized MV was performed in all patients. The arterialized MV was sampled and examined histologically to determine the percentage of the hyperplasia of venous wall (hypertrophic ratio). Histological examination of arterialized MV showed that hypertrophic alteration of venous wall structure was due to hyperplasia of elastic fibers, ranging from 41 to 82%. Patients with angiographically severe venous hypertension tended to have a higher hypertrophic ratio than patients with moderate venous hypertension. Our observations support the clinical concept that long-standing arterial stress in the spinal venous circulation causes histological alterations of spinal vascular structure associated with the progression of venous hypertension. We suggested that possibly the histological parameter can be used for predicting neurological recovery after occlusion of the fistulas.

Microsurgical interruption of dural arteriovenous fistula at the foramen magnum.

We report two rare cases of progressive congestive myelopathy caused by dural arteriovenous fistulae (DAVF) at the foramen magnum. The first, a 69-year-old male with a 2-year history of progressive myelopathy, had symptoms unrecognized due to a past history that included spinal caries and congenital dislocation of the hip. The second, a 60-year-old male, had a recurrence of the myelopathy three months after endovascular occlusion of the DAVF feeding artery. Both patients were successfully treated by direct microsurgical interruption of the arterialized medullary vein with functional and radiological improvement. The clinical manifestations of DAVF at the foramen magnum are nonspecific, mimicking those of cervical spondylotic myelopathy or cervical neoplasm. Accurate and early diagnosis followed by complete obliteration of the fistula is mandatory to avoid permanent neurological deficit.

Usefulness of interventional embolization of the middle meningeal artery for recurrent chronic subdural hematoma: Five cases and a review of the literature.

PURPOSE: Although several strategies against recurrent chronic subdural hematoma (CSDH) have been proposed, no consensus has been established. Recently, middle meningeal artery (MMA) embolization has been proposed as radical treatment for recurrent CSDH. We wanted to estimate the usefulness of MMA embolization for recurrent CSDH. METHODS: From February 2012 to June 2013, 110 patients with CSDH underwent single burr-hole surgery with irrigation and drainage. Among these patients, 13 showed recurrent hematoma formation and were retreated surgically. Furthermore, repeated recurrence of CSDH was observed in six patients. Five of these six patients underwent middle meningeal artery (MMA) embolization with polyvinyl alcohol particles. All five patients with interventional treatment were observed for four to 60 weeks. RESULTS: No more recurrence of CSDH was observed in any of the patients. During the follow-up period, no patients suffered from any side effects or complications from the interventional treatment. CONCLUSION: MMA embolization with careful attention paid to the procedure might be a treatment of choice for recurrent CSDH.

Prevention of postoperative posterior tethering of spinal cord after resection of ependymoma.

OBJECT: The authors evaluated an alternative method to avoid postoperative posterior tethering of the spinal cord following resection of spinal ependymomas. METHODS: Twenty-five patients with spinal ependymoma underwent surgery between 1978 and 2002. There were 16 male and nine female patients whose ages at the time of surgery ranged from 14 to 64 years (mean 41.8 years). The follow-up period ranged from 6 to 279 months (mean 112.4 months). In the initial 17 patients (Group A), the procedure to prevent arachnoidal adhesion consisted of the layer-to-layer closure of three meninges and laminoplasty. In the subsequently treated eight patients (Group B), the authors performed an alternative technique that included pial suturing, dural closure with Gore-Tex membrane-assisted patch grafting, and expansive laminoplasty. In Group A, postoperative adhesion was radiologically detected in eight cases (47%), and delayed neurological deterioration secondary to posterior tethering of the cord was found in five cases. In Group B, there was no evidence of adhesive posterior tethering or delayed neurological deterioration. A significant intergroup statistical difference was demonstrated for radiologically documented posterior tethering (p < 0.05, Fisher exact test). Moreover, patients with radiologically demonstrated posterior tethering suffered a significant delayed neurological functional deterioration (p < 0.01, Fisher exact test). CONCLUSIONS: This new technique for closure of the surgical wound is effective in preventing of postoperative posterior spinal cord tethering after excision of spinal ependymoma.

Hydroxyapatite laminar spacers and titanium miniplates in cervical laminoplasty.

OBJECTIVE: The authors describe a new surgical technique for cervical laminoplasty that was performed in 25 patients. The posterior elements along with the various ligaments are removed en bloc and are stabilized in a lift-up position by placing hydroxyapatite (HA) laminar spacers and titanium miniplates and screws. The procedure and clinical results are discussed. METHODS: The posterior spinal elements, including the lamina(e), spinous process(es), and various attached ligaments, are removed en bloc by incising the lamina in its lateral aspect. Trapezoid-shaped HA spacers are placed between the cut ends of the laminae or between the laminae and lateral masses bilaterally at each level. Malleable titanium miniplates and screws are used for fixation of the spacers. The fixation of transected laminae was judged to be successful. Postoperative care included application of a soft neck collar for 1 week but no further restriction of activity. Surgery-related outcome was assessed in the 21 patients who attended more than 6 months of follow up after laminoplasty. There were 18 men and three women who ranged in age from 27 to 81 years. Cervical stenotic myelopathy was demonstrated in 15 patients who underwent decompressive and expansive laminoplasty, and spinal tumors were documented in six patients who underwent a nonexpansive laminoplasty. Postoperative and follow-up computerized tomography scans demonstrated no hardware failure. Bone formation around the spacers was observed either at 6- or at 9-month follow-up examination in all 21 patients. Fusion of the reconstructed laminae was found to be completed at 12 months in all 18 patients able to attend follow up for this duration. Spinal alignment and the range of motion of the cervical spine were well preserved. In patients with stenotic cervical myelopathy, neurological and anatomical outcome of canal expansion were satisfactory. CONCLUSIONS: This technique enables rigid laminoplasty while maintaining anatomical and biomechanical integrity of posterior elements of cervical spine. Expansive and nonexpansive laminoplasty procedures are possible.

Methionine positron emission tomography for differentiation of recurrent brain tumor and radiation necrosis after stereotactic radiosurgery--in malignant glioma.

OBJECT: Following stereotactic radiosurgery (SRS), we examined how to differentiate radiation necrosis from recurrent malignant glioma using positron emission tomography (PET) with 11C-methionine (Met). METHODS: Met-PET scans were obtained from 11 adult cases of recurrent malignant glioma or radiation injury, suspected on the basis of magnetic resonance images (MRI). Patients had previously been treated with SRS after primary treatment. PET images were obtained as a static scan of 10 minutes performed 20 minutes after injection of Met. We defined two visual grades (e.g., positive or negative Met accumulation). On Met-PET scans, the portion of the tumor with the highest accumulation was selected as the region of interest (ROI), tumor-versus-normal ratio (TN) was defined as the ratio of average radioisotope counts per pixel in the tumor (T), divided by average counts per pixel in normal gray matter (N). The standardized uptake value (SUV) was calculated over the same tumor ROI. Met-PET scan accuracy was evaluated by correlating findings with subsequent histological analysis (8 cases) or, in cases without surgery or biopsy, by the subsequent clinical course and MR findings (3 cases). RESULTS: Histological examinations in 8 cases showed viable glioma cells with necrosis in 6 cases, and necrosis without viable tumor cells in 2 cases. Three other cases were considered to have radiation necrosis because they exhibited stable neurological symptoms with no sign of massive enlargement of the lesion on follow-up MR after 5 months. Mean TN was 1.31 in the radiation necrosis group (5 cases) and 1.87 in the tumor recurrence group (6 cases). Mean SUV was 1.81 in the necrosis group and 2.44 in the recurrence group. There were no statistically significant differences between the recurrence and necrosis groups in TN or SUV. Furthermore, we made a 2 x 2 factorial cross table (accumulation or no accumulation, recurrence or necrosis). From this result, the Met-PET sensitivity, specificity, and accuracy in detecting tumor recurrence were determined to be 100%, 60%, and 82% respectively. In a false positive-case, glial fibrillary acidic protein (GFAP) immunostaining showed a positive finding. CONCLUSION: There were no significant differences between recurrent malignant glioma and radiation necrosis following SRS in Met-PET. However, this study shows Met-PET has a sensitivity and accuracy for differentiating between recurrent glioma and necrosis, and presents important information for developing treatment strategies against post radiation reactions.

Evaluation of treatment effects in brain abscess with positron emission tomography: comparison of fluorine-18-fluorodeoxyglucose and carbon-11-methionine.

Positron emission tomography (PET) imaging is in common use preoperatively to clinically evaluate patients who present with central nervous system mass lesions. The usefulness of PET is also recognized as a method to detect intracranial tumorous lesions. A number of papers reportthat some inflammatory processes also showed the uptake of Fluorine-18-Fluorodeoxyglucose (FDG) and Carbon-11-Methionine (Met) tracers. We performed two PET studies before and after treatment in 4 patients with brain abscess. PET showed the uptake of both tracers to thebrain abscess before treatment. The area showing an increased uptake of Met corresponded closely to the enhanced area on both CT and MR images. FDG-PET visually showed an uptake of FDG in a small area corresponding to an enhanced lesion within the CT and MR images. After treatment the area of lesions became small on enhancement CT or MRI and both PET studies showed reduced lesion and decreased uptake. The mechanism of Met uptake in the inflammatory area may be related to the higher metabolic rate and the active transport of amino acids as well as disruption of the blood brain barrier. Furthermore, it appears that the mechanism of FDG uptake is also related to a higher metabolic rate and, in addition, is related to the increased density of inflammatory cells. PET studies, more directly, reflect the degree of inflammatory response in brain abscess than enhancement CT or MRI. Therefore, PET is useful in detecting the inflammatory lesion and assessing the clinical effects of antibiotics treatment on brain abscesses.

Dural arteriovenous fistula involving the superior sagittal sinus following sinus thrombosis--case report.

A 57-year-old woman presented with a dural arteriovenous fistula (AVF) involving the superior sagittal sinus (SSS) based upon serial radiological examinations. Her chief complaints were headache and vomiting. Cerebral angiography and magnetic resonance (MR) venography revealed the sinus thrombosis involving the SSS, the bilateral transverse sinuses (TSs), and the right sigmoid sinus. Her symptoms disappeared after anticoagulant therapy. Follow-up MR venography revealed almost complete recanalization of the occluded sinuses, followed by restenosis of the SSS and the left TS and occlusion of the right TS without symptoms. She developed transient right hemiparesis 13 months after the initial onset. Cerebral angiography revealed a dural AVF involving the SSS with cortical reflux into the left frontoparietal region. The dural AVF was occluded by transarterial and transvenous embolization. Her symptom disappeared during the follow-up period.

Percutaneous transluminal angioplasty and stent placement for subclavian steal syndrome with concomitant anterograde flow in the left internal mammary artery graft for coronary artery bypass--case report.

A 63-year-old man presented with subclavian steal syndrome associated with left internal mammary artery (IMA) bypass graft to a coronary artery. He was admitted with a history of oppressive sensation in the chest, dizziness, and light headedness on exertion for 2 weeks in March 2002. He had undergone myocardial revascularization consisting of a left IMA-to-left anterior descending coronary artery graft in April 1988. His blood pressure was 140/70 mmHg in the right arm and 80/64 mmHg in the left arm. Aortic arch arteriography revealed complete occlusion of the left subclavian artery proximal to the left IMA takeoff and subclavian steal with anterograde flow of the left IMA. Percutaneous angioplasty and stent placement with protection of the left IMA bypass graft using a balloon catheter was successfully performed without complication by cerebral or myocardial ischemia. Complete recanalization of the occluded left subclavian artery and anterograde flow of the left vertebral artery were achieved. His symptoms disappeared and blood pressure in the left arm recovered. This variant of coronary subclavian steal might require protection of the left IMA during angioplasty and stent placement.