Subclinical Cushing's Disease with High-Molecular-Weight Forms of Adrenocorticotropic Hormone Production.

Production of the high-molecular-weight forms of adrenocorticotropic hormone (big-ACTH) has been reported in a small number of ectopic ACTH syndrome and ACTH-producing pituitary macroadenoma. However, perioperative changes in big-ACTH in patients with subclinical Cushing's disease have not been reported. A 63-year-old woman presented 25 × 20 × 20-mm-sized macroadenoma in the pituitary gland. Her early morning plasma ACTH and cortisol levels were 111 pg/mL and 11.6 µg/dL, respectively. Cushingoid features and diurnal variation in plasma cortisol levels were not observed. The patient's urinary free cortisol (UFC) was 59.3 µg/day. The corticotropin-releasing hormone (CRH) test showed that plasma ACTH levels were 1.5 times higher than the preload value. The overnight dexamethasone suppression test (DST) showed that the plasma cortisol level was not suppressed by 0.5 mg of dexamethasone (DEX) but was suppressed by 8 mg of DEX. Inferior pyramidal sinus sampling was consistent with Cushing's disease. Taken together, the patient was clinically diagnosed with subclinical Cushing's disease caused by an ACTH-producing pituitary adenoma. Endoscopic transsphenoidal adenomectomy was performed. In the postoperative CRH test, plasma ACTH levels showed six-fold increase. The postoperative DST showed cortisol suppression at 0.5 mg of DEX. The UFC levels decreased to 35.1 µg/day. Pituitary contrast-enhanced MRI revealed no residual tumor, and plasma ACTH and cortisol levels remained within normal ranges. Gel filtration of preoperative and postoperative plasma ACTH was performed, and a high molecular weight fraction of ACTH was detected, which markedly decreased postoperatively. The absence of Cushingoid features and the lack of significant cortisol hypersecretion in this case were thought to be due in part to big-ACTH, which has low bioactivity. By careful evaluation of laboratory and clinical findings, we identified it as a big-ACTH-producing adenoma. This is the first report of a case in which the big-ACTH transition was observed perioperative and is a valuable case.

Maximal Resection of Gliomas Adjacent to the Corticospinal Tract Using 3-T Intraoperative Magnetic Resonance Imaging.

BACKGROUND: Gliomas adjacent to the corticospinal tract (CST) should be carefully resected to preserve motor function while achieving maximal surgical resection. Modern high-field intraoperative magnetic resonance imaging (iMRI) enables precise visualization of the residual tumor and intraoperative tractography. We prospectively evaluated the extent of resection and distance between the tumor resection cavity and CST using 3-T iMRI combined with motor evoked potentials (MEP) in glioma surgery. METHODS: Participants comprised patients who underwent surgery for solitary supratentorial glioma located within 10 mm of the CST. All cases underwent surgery using neuronavigation with overlaid CST under MEP monitoring. The correlation between distance from CST and transcortical MEP amplitude was calculated using Spearman rank correlation. RESULTS: Among the 63 patients who underwent surgery, 27 patients were enrolled in the study. Gross total resections were achieved in 26 of the 27 cases. Volumetric analysis showed the extent of resection was 98.6%. Motor function was stable or improved in 24 patients (Stable/Improved group) and deteriorated in 3 patients (Deteriorated group). All patients in the Deteriorated group showed motor deficit before surgery. Mean intraoperative minimal distance was significantly longer in the Stable/Improved group (7.3 mm) than in the Deteriorated group (1.1 mm; P < 0.05). MEP amplitude correlated with minimal distance between the resection cavity and CST (R = 0.64). CONCLUSIONS: Resection of gliomas adjacent to CST with a navigation system using 3-T iMRI could result in an ultimate EOR >98%. The combination of intraoperative tractography and MEP contributes to maximal removal of motor-eloquent gliomas.

Analysis of vascular perfusion territory using selective intraarterial injection CT angiography before and after revascularization surgery in patients with moyamoya disease.

OBJECTIVE: In moyamoya disease (MMD), blood flow to the internal carotid artery (ICA) system is supplied via the basal fine vascular network, leptomeningeal anastomoses, and transdural collateral vessels from the external carotid artery (ECA). After revascularization, there is a dramatic change in cerebral perfusion to the ECA system. Understanding this shift in blood supply is important for evaluating treatment efficacy and elucidating the postoperative pathophysiology. However, anatomical and quantitative methods for doing so have not yet been established. In the present study, selective intraarterial injection CT angiography (iaCTA) was performed in patients with MMD, and blood supply changes in each arterial system before and after revascularization surgery were evaluated. METHODS: This study included 10 hemispheres in 10 patients who underwent combined revascularization surgery for adult MMD. Digital subtraction angiography was performed before and 3 months after surgery, and selective iaCTA was performed from the ICA, ECA, and vertebral artery (VA) at the same times in a hybrid CT/digital subtraction angiography suite. The anatomical distribution of each vessel was determined and perfusion volume was measured quantitatively on contrast-enhanced axial CT images. RESULTS: Selective iaCTA clearly depicted the anatomical distribution of perfusion for each vessel. Conversion of blood supply from the ICA and VA to the ECA system was observed in the cerebral cortices and insulae but not in the basal ganglia. The mean volume of perfusion territories of the ECA (preoperative 0.9 cm3, postoperative 98.8 cm3); ICA (preoperative 225.7 cm3, postoperative 159.3 cm3); and VA (preoperative 244.0 cm3, postoperative 163.6 cm3) in the cerebral hemispheres changed significantly after revascularization. There was a correlation between increase in the ECA territory volume and decrease in the VA territory volume due to revascularization (R = -0.84, p < 0.005). CONCLUSIONS: Selective iaCTA enabled clear visualization of anatomical changes in each vascular perfusion territory and quantitative measurement of each perfusion volume. Perfusion conversion to the ECA system after bypass surgery was observed in the cortical regions and in the insulae on the bypass operation sides, but not in the basal ganglia. Combined revascularization promoted the development of ECA-perfused territory, which correlated with a decrease in hemodynamic burden of the posterior cerebral artery.

Nonconvulsive status epilepticus due to pneumocephalus after suprasellar arachnoid cyst fenestration with transsphenoidal surgery: illustrative case.

BACKGROUND: Nonconvulsive status epilepticus (NCSE) requires prompt diagnosis and treatment, particularly after neurosurgical procedures for cerebral damage. Here, the authors reported an extremely rare case of suprasellar arachnoid cyst presenting with NCSE after cyst fenestration with transsphenoidal surgery, which was associated with pneumocephalus. OBSERVATIONS: A 61-year-old man presented with visual impairment and was diagnosed with a suprasellar arachnoid cyst on magnetic resonance imaging (MRI). The patient received cyst fenestration with endonasal transsphenoidal surgery. His visual symptoms improved immediately after the operation; however, on postoperative day 3, semicoma appeared and was prolonged. The patient was diagnosed with NCSE due to pneumocephalus based on MRI and electroencephalography (EEG) findings. The administration of antiepileptic drugs (AEDs) improved his clinical symptoms and the abnormal findings on MRI and EEG. LESSONS: This is the first case of NCSE with pneumocephalus after transsphenoidal surgery for a suprasellar arachnoid cyst. Pneumocephalus due to cerebrospinal fluid leakage can cause NCSE. Arterial spin labeling perfusion imaging and diffusion-weighted imaging are as useful for differentially diagnosing NCSE as EEG and AED tests.

An Adult Case of Sellar Atypical Teratoid/Rhabdoid Tumor Presenting with Lung Metastasis, Harboring a Compound Heterozygous Mutation in INI1.

A typical teratoid/rhabdoid tumors (AT/RT) are highly malignant embryonal tumors in children that are associated with inactivation of the integrase interactor 1 (INI1) gene. Several adult cases of AT/RT have been reported, which were characterized by the sellar occurrence and predominantly occurred in females with INI1 mutation variants. However, clinical and genetic features are poorly understood in this unusual entity. We experienced a case of a 45-year-old female with sellar AT/RT presenting diplopia, who underwent subtotal removal of the tumor by the endoscopic endonasal transsphenoidal approach. Pathological diagnosis was AT/RT with INI1 inactivation on immunohistochemistry. Subsequently, multiple lung metastases were confirmed on fluorodeoxyglucose positron emission tomography (FDG-PET). Although she received postoperative chemoradiotherapy, she died of cerebrospinal fluid dissemination. Autopsy revealed cerebrospinal dissemination and lung metastasis of AT/RT. Biallelic alterations in the INI1 gene were identified by direct sequencing, harboring on different alleles (compound heterozygous mutations) was observed, which is the potential genetic pattern in adult AT/RT. Literature review indicated that lung metastasis frequently occurs in sellar AT/RTs, which is accompanied by cavernous sinus invasion. These observations suggested that cavernous sinus invasion causes haematogenous metastasis to the lung in sellar AT/RT. We discuss clinical and pathological features in adult sellar AT/RT to improve understanding of this unique entity.

Anterior Approach Combined with Endoscopic Fluorescence Video Angiography for a Cervical Perimedullary Arteriovenous Fistula.

BACKGROUND: Perimedullary arteriovenous fistulas (pAVFs) of the anterior cervical spinal cord are rare and difficult to eradicate by surgery because of the limitations of the approach routes. Because of the anatomic relationships, an anterior approach with corpectomy can provide direct observation. However, a narrow corridor to the lesion is the drawback of this approach. Therefore, to overcome this limitation, we introduced angled endoscopes integrated with fluorescence video angiography to observe the real-time blood flow. CASE DESCRIPTION: A 47-year-old woman was incidentally found to have a pAVF fed by multiple radicular arteries, and she underwent direct surgery via the anterior approach. Although observation of the entire lesion was difficult with the microscope alone, the introduction of the angled endoscope made it possible to observe the lateral portion of the spinal cord hidden behind the dura mater. Furthermore, endoscopic fluorescein video angiography visualized residual fine feeding arteries that were then electrocoagulated, which contributed to complete obliteration of the shunt. CONCLUSIONS: The anterior approach with endoscopic assistance is a reasonable strategy for the treatment of ventrally located cervical pAVFs. Furthermore, integration of a fluorescence video angiography system with the endoscope enables confirmation of the complicated real-time hemodynamics of the pAVFs, contributing to reliable treatment.

Endoscope-Integrated Fluorescence Video Angiography for the Surgery of Ventrally Located Perimedullary Arteriovenous Fistula at Craniocervical Junction.

BACKGROUND: Intraoperative confirmation of the vascular anatomy and blood flow contributes to the safety of the surgery for perimedullary arteriovenous fistulas (PAVF). However, because the PAVF at the craniocervical junction (CCJ) is mainly located on the ventral spinal cord surface, it is difficult to observe the entire pathology by a conventional surgical approach. To achieve increased viewing angle and visualization of real time blood flow, we introduced endoscope-integrated fluorescein video angiography in the treatment for PAVF at the CCJ for the first time. CASE DESCRIPTION: A 63-year-old man presented with subarachnoid hemorrhage due to rupture of PAVF at the CCJ, fed by both the right C1 radiculomedullary artery and the anterior spinal artery (ASA). Suboccipital craniotomy and C1 hemilaminotomy was performed and microscopic observation revealed partial anatomy of the PAVF covered by subarachnoid clots on the ventrolateral surface at the right C1 nerve root level. However, pathology ventral to the C1 nerve root was obscure and an endoscope-integrated fluorescein video angiography was introduced, which clearly demonstrated the PAVF components and the ASA. CONCLUSIONS: According to these findings, the PAVF was coagulated and the ASA was preserved. Endoscope-integrated fluorescein video angiography allowed to visualize its real-time blood flow, leading to a safe and reliable treatment.

Left-Right and Upper-Lower Light Sensitivity Asymmetry in Visual Field Defects Caused by Pituitary Adenoma: A Retrospective Observational Study.

PURPOSE: The purpose of this study was to quantitatively investigate light sensitivity asymmetry both between left and right eyes and between upper and lower quadrant in the 30-degree visual field of patients with visual field defects caused by pituitary adenoma. PATIENTS AND METHODS: Preoperative Humphrey 30-2 perimetry results were reviewed retrospectively using the charts of 28 pituitary adenoma patients who underwent surgery. Inter-eye light sensitivity comparisons of the temporal and nasal hemifields between the left and right eyes were conducted in each patient to study left-right asymmetry. Upper-lower asymmetry was investigated by comparing the frequency of severe scotoma (light sensitivity 5 dB or less) in the upper and lower visual field quadrants in the temporal and nasal hemifields. RESULTS: Left-right asymmetry was demonstrated in 61% of cases in the temporal hemifield and in 57% of cases in the nasal hemifield. Severe scotoma test points were investigated in the worse eye of each patient and were more frequent in the superotemporal quadrant of the visual field compared with the inferotemporal quadrant (P = 0.00029) and in the inferonasal quadrant compared to the superonasal quadrant (P = 0.00268). CONCLUSION: Asymmetric visual field defects between left and right eyes are common in patients with pituitary adenoma. Severe scotoma is more frequent in the upper quadrant of the temporal hemifield and in the lower quadrant of the nasal hemifield.

GH/PRL-secreting pituitary macroadenoma associated with GNAS p.Gln227Leu mutation: pediatric case report and review.

GH-secreting pituitary adenomas (GHomas) are rare in the pediatric population. Guanine nucleotide-binding protein, alpha stimulating (GNAS) somatic mutations are often found in patients with GHoma. Here, we report an 8-year-old girl with GH-secreting pituitary adenoma successfully treated by operative tumor resection and postoperative treatment with octreotide long-acting release (LAR). Tumor DNA sequence analysis revealed a somatic heterozygous c.680A>T (p.Gln227Leu) mutation in GNAS. We reviewed 1,084 cases of GHomas, 409 (37.7%) of which harbored GNAS mutations. In pediatrics cases, aged 15 years or younger, 11 harbored a GNAS mutation, and GNAS p.Arg201Cys was identified in five cases. No other cases of codon 227 mutation were detected. These cases suggest that, in pediatric patients, the clinical features of GHoma may differ from those observed in adults. This is possibly related to octreotide or dopamine agonist resistance. Of six patients with surgical resistance, only one was reactive when treated with octreotide. Our case shows that octreotide LAR is an effective choice for treating GNAS-induced GHoma. This is the first report detailing the effectiveness of octreotide LAR in a GNAS codon 227 mutation-induced GHoma in a pediatric case. Examination of the relationship between genetic variation and clinical features in pediatric patients will enable us to assess the long-term effects of surgical and medical treatment of GHomas.

Efficacy of Intraarterial Fluorescence Video Angiography in Surgery for Dural and Perimedullary Arteriovenous Fistula at Craniocervical Junction.

OBJECTIVE: Confirming the exact location of a fistula and the origins of draining veins during surgery for dural and perimedullary arteriovenous fistulas (AVFs) is crucial but sometimes inadequately performed, which can result in incomplete elimination of the lesion. Intraoperative digital subtraction angiography (DSA) is the gold standard for confirming the hemodynamics of an AVF; however, it cannot reveal the location of an AVF in the operative field. In this study, the efficacy of intraoperative intraarterial fluorescence video angiography during surgery for craniocervical junction dural and perimedullary AVFs was investigated. METHODS: We repeatedly employed this technology to evaluate its usefulness in revealing the flow dynamics and anatomy of AVFs and to confirm complete elimination of the fistula. RESULTS: Seven AVFs were included in this study. Their locations were C1 in 5 cases and C2 in 2 cases. Intraarterial fluorescence video angiography precisely revealed the locations of 3 dural AVFs, 1 perimedullary AVF, and 3 co-occurring dural and perimedullary AVFs. Frame-by-frame review of the fluorescence video angiography clearly demonstrated that fluorescence appeared earlier in the perimedullary AVF than in the draining vein through the dural AVF after intraarterial injection in all 3 co-occurring cases. Complete elimination of the AVF was also confirmed in all cases by fluorescence video angiography, as well as intraoperative and follow-up DSA. CONCLUSIONS: Intraarterial fluorescence video angiography, particularly frame-by-frame review, enables surgeons to distinguish the flow dynamics of AVFs and contributes to the planning of effective surgical strategies for optimal results.

Xanthogranuloma of the sellar region accompanied by growth hormone deficiency: case report and literature review.

Background Xanthogranuloma of the sellar region is a rare entity. Its pathology is controversial and it is difficult to strictly differentiate it from craniopharyngioma or Rathke's cyst. Case presentation We report a case of xanthogranuloma accompanied by growth hormone deficiency in an 11-year-old girl. She did not show any other pituitary hormone deficiency or neurological symptoms before operation. The preoperative diagnosis was craniopharyngioma, but histological findings showed small areas of epithelium. Thus, the final diagnosis was xanthogranuloma. Xanthogranuloma is an important cause of growth delay. We reviewed 16 cases reported after 2000, and included our case, of xanthogranuloma in children. Conclusions Endocrinological symptoms are often regarded as one of the few apparent symptoms in xanthogranuloma compared with craniopharyngioma. Therefore, we should follow up carefully and accumulate cases.

[Spontaneous Improvement in Visual Symptom after Delivery in a Case of Tuberculum Sellae Meningioma].

A 36-year-old woman presented with temporal visual field defect in the 27th week of her pregnancy. Magnetic resonance(MR)imaging demonstrated a tuberculum sellae meningioma compressing the optic chiasm. Although we planned surgical resection after her delivery, the symptom worsened in the late stage of her pregnancy. After administering a steroid medication, the symptom stabilized. In the 38th week of pregnancy, she delivered a child, and interestingly, her visual field defect improved, and MR imaging demonstrated tumor shrinkage. However, at the request of the patient, we performed the tumor resection by extended endonasal transsphenoidal surgery. The histological diagnosis was angiomatous meningioma, and the tumor cells were strongly positive for progesterone receptors. This is a very rare case of tuberculum meningioma wherein the patient showed a natural improvement in visual function after delivery. Regarding the appropriate surgical timing for meningioma, spontaneous shrinkage of meningioma after delivery would be considered an option.

Efficacy of Endoscopic Fluorescein Video Angiography in Aneurysm Surgery-Novel and Innovative Assessment of Vascular Blood Flow in the Dead Angles of the Microscope.

BACKGROUND: In aneurysm surgery, assessment of the blood flow around the aneurysm is crucial. Recently, intraoperative fluorescence video angiography has been widely adopted for this purpose. However, the observation field of this procedure is limited to the microscopic view, and it is difficult to visualize blood flow obscured by the skull base anatomy, parent arteries, and aneurysm. OBJECTIVE: To demonstrate the efficacy of a new small-caliber endoscopic fluorescence video angiography system employing sodium fluorescein in aneurysm surgery for the first time. METHODS: Eighteen patients with 18 cerebral aneurysms were enrolled in this study. Both microscopic fluorescence angiography and endoscopic fluorescein video angiography were performed before and after clip placement. RESULTS: Endoscopic fluorescein video angiography provided bright fluorescence imaging even with a 2.7-mm-diameter endoscope and clearly revealed blood flow within the vessels in the dead angle areas of the microscope in all 18 aneurysms. Consequently, it revealed information about aneurysmal occlusion and perforator patency in 15 aneurysms (83.3%) that was not obtainable with microscopic fluorescence video angiography. Furthermore, only endoscopic video angiography detected the incomplete clipping in 2 aneurysms and the occlusion of the perforating branches in 3 aneurysms, which led to the reapplication of clips in 2 aneurysms. CONCLUSION: The innovative endoscopic fluorescein video angiography system we developed features a small-caliber endoscope and bright fluorescence images. Because it reveals blood flow in the dead angle areas of the microscope, this novel system could contribute to the safety and long-term effectiveness of aneurysm surgery even in a narrow operative field.

[Efficacy and Safety of Levetiracetam as an Add-on Therapy for Symptomatic Refractory Epilepsy Treated in a Department of Neurosurgery].

The number of patients who suffer from symptomatic partial epilepsy is significant, and those who undergo neurosurgery often experience refractory seizures. Levetiracetam (LEV) is a new-generation anti epileptic drug (AED). Previous studies have shown that LEV has favorable efficacy and a good safety profile with few drug interactions, as it has a unique pharmacological mechanism and acts on synaptic vesicle protein. This study aimed at estimate the efficacy and safety of 1,000 to 2,000 mg/day of LEV as an add-on therapy for refractory symptomatic seizures treated in the department of neurosurgery of our hospital. Twelve patients with >1 seizure attack per year who were administrated one to three AED(s) and had never used LEV were enrolled in this study. The follow-up period was at least 6 months. Seizure-free ratio, health-related quality of life (QOL), and tolerability were assessed. Fifty-eight percent (7/12) of patients were seizure-free, and their "overall QOL", "energy/fatigue" and "health status" distress-item scores in the QOLIE-31-P had improved. All patients were able to continue oral treatment with LEV without major side effects. Thus, the efficacy and safety of oral add-on LEV therapy were high for these patients. (Received January 19, 2016; Accepted September 2, 2016; Published December 1, 2016).

A case of complete clearance of chronic subdural hematoma accompanied by recurrent glioblastoma multiforme after administration of bevacizumab.

The efficacy of bevacizumab, a humanized monoclonal antibody against vascular endothelial growth factor (VEGF), as an adjuvant therapy against various malignant tumors was recently established. Its pharmacological effects in malignant tumors, including gliomas, were speculated to involve neovascularization inhibition and vascular permeability. Recently, it has been reported that the outer membrane of chronic subdural hematoma (CSDH) contains high levels of VEGF, which were implicated in neovascularization of the outer membrane. Furthermore, studies suggested that VEGF has the etiology in CSDH development, although its involvement is not fully understood. Here, we report the first case of chronic subdural hematoma that was improved by bevacizumab administration for recurrent glioblastoma. The present case could contribute to the hypothesis that VEGF may be associated with CSDH. We also discuss the pathogenesis and mechanism of CSDH recurrence from the viewpoint of VEGF function.

Simultaneous onset of anterior and middle cerebral artery dissections with an old vertebral artery dissection.

Multiple arterial dissections in the anterior circulation with simultaneous onset are extremely rare. We report a patient with infarctions caused by simultaneous arterial dissections in the right anterior cerebral artery and the left middle cerebral artery and discuss the characteristic feature of this vascular disorder. A 53-year-old woman presented with a severe headache and a mild aphasia. Magnetic resonance imaging revealed multiple acute cerebral infarctions in the left temporal and right frontal lobes. The initial angiographic findings revealed arterial dissections of the anterior cerebral, left middle cerebral, and right vertebral arteries. The follow-up angiographic examination found improvement of the stenosis in both the anterior cerebral and middle cerebral arteries. We have concluded that the lesion of the vertebral artery was not in an acute stage, because no interval change was seen during the radiologic evaluation. She underwent conservative therapy, and her symptoms disappeared. Multiple arterial dissections are rare, especially those developing simultaneously in different arteries. This is the first case of multiple arterial dissections of the different arteries in the anterior circulation manifesting cerebral infarction simultaneously.

Intra-arterial injection fluorescein videoangiography in aneurysm surgery.

BACKGROUND: To visualize blood flow in the arteries and aneurysm during surgery, intravenous fluorescence videoangiography has been used. However, the image contrast with this procedure is diminished by repeated study because the dye remains for about 10 minutes after injection. OBJECTIVE: To determine the optimal dye concentration and to clarify the usefulness of fluorescein videoangiography by intra-arterial dye injection. METHODS: In the pilot study, fluorescein sodium dissolved at various concentrations was illuminated with excitation light, and fluorescence was detected by cameras. The fluorescence of 0.001% fluorescein sodium solution mixed with plasma at various concentrations was then examined. In 13 aneurysm patients, dye solution was administered through the catheter for intraoperative digital subtraction angiography. The intravenous injection method was also performed, and the findings were compared. RESULTS: Dye was clinically used at a concentration of 0.005% to 0.1% on the basis of the results of the pilot study. Fluorescence emission from the vessels and aneurysms was clearly observed by both methods; however, arterial injection provided brighter emission, resulting in clearer demonstration of the bloodstream than venous injection. Dye clearance was also quicker, which allowed repeat injections without delay. Dye filling in the aneurysm indicating incomplete occlusion was detected in 2 cases, and occlusion of the perforating artery was observed in 2 cases. CONCLUSION: Intra-arterial fluorescein videoangiography provides brighter and clearer imaging of blood flow with a smaller dose of dye than intravenous videoangiography. It can be repeated within a short time and is useful for detecting incomplete clipping or unexpected obstruction of arteries.

Surface rendered three-dimensional MR imaging for the evaluation of trigeminal neuralgia and hemifacial spasm.

Surface rendered three-dimensional (SR3D) magnetic resonance (MR) imaging was used to visualize the cerebellopontine angle nerves, blood vessels and brain stem and compared with the operative view in patients undergoing microvascular decompression. Thirty-one patients with 32 affected nerves manifesting as trigeminal neuralgia (TN, 16 cases), hemifacial spasm (HFS, 14 cases) and glossopharyngeal neuralgia (2 cases) underwent microvascular decompression at the Kanto Neurosurgical Hospital between February 2001 and July 2002. Preoperative MR imaging and MR angiography were performed in all patients. The SR3D MR image and the operative view correlated in 30 of the 31 patients. A very thin artery was not detected in one patient with TN. SR3D MR imaging can clearly demonstrate the three-dimensional relationship between the nerves and the offending vessel, so is very effective for the preoperative planning of microvascular decompression in cases of TN and HFS.