Ryosuke Okumura

Demonstration of neurovascular compression in trigeminal neuralgia and hemifacial spasm with magnetic resonance imaging: comparison with surgical findings in 60 consecutive cases.

BACKGROUND Until recently, it has been impossible to demonstrate vascular compression at the root entry or exit zone (REZ) of the trigeminal nerve and facial nerve in patients with trigeminal neuralgia (TN) and hemifacial spasm (HFS) preoperatively, although surgical findings have revealed apparent neurovascular compression and its correction has resulted in a good outcome in most cases. Revealing the anatomic correlation between nerves and vessels at the REZ preoperatively would be useful to predict operative findings. METHODS To assess whether the vascular contact of the nerve at the REZ could be demonstrated preoperatively, high-resolution magnetic resonance tomographic angiography (MRTA) was performed in 21 patients with TN and 39 with HFS. Neuroradiological findings were compared with the operative findings in all patients. Contralateral asymptomatic nerves were evaluated as a control. RESULTS MRTA correctly identified offending vessels in 14 (67%) of the 21 TN and 34 (87%) of the 39 HFS patients. Failure to identify neurovascular contact was noted in the cases with compression by veins or small arteries, thickened arachnoid, or distal compression. Neurovascular contact was also observed in 15% of the asymptomatic nerves. The deformity of the nerve seemed to be a more important factor for determining operative indication. CONCLUSIONS MRTA could demonstrate offending vessels in TN and HFS at a high rate and was useful to predict operative findings. MRTA gave supportive evidence of surgical indications in patients with TN and HFS, although attention should be paid to the fact that MRTA did not necessarily detect all of the offending vessels.

Magnetic resonance imaging of neurohypophyseal germinomas

The authors reviewed magnetic resonance (MR) images in seven cases of germinoma in the hypothalamoneurohypophyseal axis (HNA). The intrasellar portions were clearly identified in six germinomas. Two small germinomas of these six were located only in the neurohypophysis. The major parts of the four large germinomas were located below the optic chiasm, and the large intrasellar portions were demonstrated. The remaining one small germinoma was localized from the pituitary stalk to the third ventricular floor. These findings strongly suggest that the primary site of germinomas in the HNA is the neurohypophysis. In the four large germinomas, the tumor shape was similar to that of pituitary adenoma. The authors believe that age (limited to first three decades), symptoms (diabetes insipidus), MR findings absence of normal hyperintense signal of the posterior pituitary on T1‐weighted (T1W1) images, and homogeneous hypointensity to the pons on T1W1 images/isointensity on T2‐weighted images are important in differential diagnosis.

Phase II study of ifosfamide, carboplatin, and etoposide in patients with a first recurrence of glioblastoma multiforme

OBJECT The prognosis of recurrent glioblastoma multiforme (GBM) remains unsatisfactory. The authors conducted a Phase II study of ifosfamide, carboplatin, and etoposide (ICE) for a first recurrence of GBM to determine whether it prolonged a patients good-quality life. METHODS This trial was an open-label, single-center Phase II study. Forty-two patients with a first GBM relapse after surgery followed by standard radiotherapy (60 Gy) and first-line temozolomide- or nimustine-based chemotherapy were eligible to participate. The primary end point was progression-free survival at 6 months after the ICE treatment (PFS-6), and secondary end points were response rate, toxicity, and overall survival. Chemotherapy consisted of ifosfamide (1000 mg/m(2) on Days 1, 2, and 3), carboplatin (110 mg/m(2) on Day 1), etoposide (100 mg/m(2) on Days 1, 2, and 3), every 6 weeks. RESULTS Progression-free survival at 6 months after ICE treatment was 35% (95% CI 22-50%). The median duration of PFS was 17 weeks (95% CI 10-24 weeks). The response rate was 25% (95% CI 9-34%). Adverse events were generally mild and consisted mainly of alopecia. CONCLUSIONS This regimen was well tolerated and has some activity and could be one of the options for patients with recurrent GBM.

A novel composite targeting method using high-field magnetic resonance imaging for subthalamic nucleus deep brain stimulation.

OBJECT Accurate localization of the subthalamic nucleus (STN) is important for proper placement of the electrodes in deep brain stimulation (DBS) surgery for patients with advanced Parkinson disease. The authors evaluated the accuracy of our modified composite targeting method and the value of using high-field MR imaging for targeting the STN. METHODS Thirteen patients with advanced Parkinson disease underwent bilateral STN DBS based on 3-T MR imaging, and 13 patients underwent surgery based on 1.5-T MR imaging. By sequentially referring to the postmammillary commissure, the red nucleus, the mammillothalamic tract, and the STN, the modified composite targeting method determined the stereotactic coordinates for targeting the STN. The accuracy and efficacy of the composite targeting method and 3-T MR imaging were evaluated by using the intraoperative microelectrode recording, the postoperative imaging study, and the postoperative clinical improvement. RESULTS The landmark structures for targeting the STN were visualized clearly with 3-T MR imaging. The mean (+/- SD) path length through the STN of the central track was 4.9 +/- 1.1 mm in the 3-T group and 3.1 +/- 2.0 mm in the 1.5-T group (p < 0.001). Twenty-one (81%) of 26 electrodes were placed in the central track in the 3-T group, whereas 8 (31%) of 26 electrodes were placed in the central track in the 1.5-T group (p = 0.006). The rest of the electrodes were placed in the noncentral optimum track for alleviating parkinsonian motor symptoms. The mean Unified Parkinsons Disease Rating Scale motor part score during off period was reduced by 53% in the 3-T group and by 41% in the 1.5-T group (p = 0.14). The mean reductions of levodopa equivalent daily doses were 48.6% in the 3-T group and 43.7% in the 1.5-T group (p = 0.61). CONCLUSIONS The use of the modified composite targeting method referring to the multiple landmarks with 3-T MR imaging offers reliable and clinically effective target for STN DBS surgery.

Degeneration of the posterior columns of the spinal cord: postmortem MRI and histopathology.

Postmortem MR images of two cases of posterior column degeneration were correlated with histopathological findings. The abnormal MR findings were volume loss and high signal intensity of the posterior columns associated with mild deformity of the dorsal surface of the spinal cord, corresponding to tract degeneration on histopathological examination. These results strongly suggest that further development of MR technique will permit in vivo detection of posterior column degeneration.

Differentiation of Suprasellar Nonneoplastic Cysts from Cystic Neoplasms by Gd-dtpa Mri

Magnetic resonance imaging in 9 cases of surgically confirmed nonneoplastic intra- and/or suprasellar cysts was analyzed and compared with that from 17 cases of craniopharyngioma and 12 of cystic pituitary adenoma. Signal intensity did not help in distinguishing nonneoplastic cysts from cystic neoplasms. No postcontrast (Gd-DTPA) cyst wall enhancement was observed among the nonneoplastic cysts, although all 6 craniopharyngiomas and 12 cystic pituitary adenomas that underwent postcontrast study did enhance. Three nonneoplastic cysts were surrounded by the pituitary gland, thus mimicking wall enhancement in the postcontrast studies. Rapid enhancement in the early postcontrast-administration phase (dynamic studies) helped avoid confusion between the normal pituitary tissue and cyst wall enhancement. Magnetic resonance studies with contrast enhancement play an essential role in differentiating nonneoplastic cysts from cystic neoplasms in the sella region.

Fatty filum terminale : assessment with MR imaging

Five cases of fatty filum terminale were encountered in a retrospective analysis of 332 routine lumbosacral magnetic resonance studies. The T1-weighted and GRASS images were particularly useful in evaluating the filum. An irregularly thickened fatty filum, especially if associated with a low conus, is likely to be pathologic and responsible for a patients symptoms and signs.

Synthesis of Hydroxymethylglutathione from Glutathione and L-Serine Catalyzed by Carboxypeptidase Y

Hydroxymethylglutathione (γ-L-glutamyl-L-cysteinyl-L-serine; hmGSH) occurs in many species belonging to the family Gramineae, but the biosynthetic pathway for hmGSH has not been identified. We found that carboxypeptidase Y (CPY), but not carboxypeptidase A, catalyzed hmGSH synthesis from glutathione and L-serine in vitro at acidic pH. CPY also catalyzed methylglutathione synthesis from glutathione and L-alanine. These findings suggested that a carboxypeptidase-like enzyme may be involved in hmGSH synthesis in vivo.

Contrast enhanced area of posterior pituitary gland in early dynamic MRI exceeds hyperintense area on T1-weighted images.

Seventeen normal pituitary glands were studied by midline sagittal (and in one case axial) dynamic MRI before and immediately after injection of Gd-DTPA, using spin-echo sequences with a short repetition time. Images were obtained at 1 min intervals for 6 min at 1.5 T. A well-defined focal area with marked enhancement was seen in the posterior portion of the pituitary gland on the first image after injection of Gd-DTPA. The size of the early enhancing area in the posterior pituitary (EEPP) was compared with the high signal of the posterior pituitary (HSPP) on the precontrast image. The EEPP was larger than the HSPP in 10 cases (59%). The two were equal in size in seven cases (41%). The EEPP was anteriorly convex in 11 cases (65%), whereas HSPP was anteriorly convex in 4 cases (24%). We believe that EEPP closely represents the real extent of the posterior lobe. Our results support the hypothesis that HSPP may involve only a portion of the posterior pituitary.

Epidural venous system (meningorachidian venous plexus) in juvenile amyotrophy of distal upper extremity: assessment with GD-DTPA enhanced volumetric MR study

The epidural venous system (meningorachidian venous plexus) was analyzed utilizing gadolinium-diethylenetriamine pentaacetic acid (DTPA) (Gd-DTPA) enhanced volumetric magnetic resonance (MR) images in 11 patients with focal cervical spinal cord atrophy, clinically consistent with juvenile amyotrophy of distal upper extremity. In our series, all of the patients showed unusual posterior epidural venous enhancement at the C5-6 level, suggesting posterior epidural venous dilatation. Three patients also showed prominent dilatation of cervico-thoracic epidural veins surrounding the thecal sac. These MR findings were also demonstrated by spinal phlebography. Gd-DTPA enhanced MR images, especially high resolutional volumetric MR images, were efficient for evaluating these vessels. The observation of meningorachidian venous plexus along the disease course should be necessary for searching the pathogenesis of this disease.