Published papers

STUDY DESIGN: Prospective longitudinal study. OBJECTIVE: The aim of this study was to evaluate long-term degenerative changes in intervertebral discs in the thoracic spine in healthy asymptomatic subjects. SUMMARY OF BACKGROUND DATA: Longitudinal magnetic resonance imaging (MRI) studies of intervertebral disc degeneration have been reported for the cervical and lumbar but not the thoracic spine. METHODS: In this longitudinal study (average follow-up 10.0 ± 0.6 years), we assessed degenerative changes in the thoracic spine of 103 volunteers (58 men) of 223 healthy volunteers in the initial MRI study of the thoracic spine (follow-up rate 46.2%). The mean age at the initial study was 45.0 ± 11.5 years (24-77 years). Initial and follow-up thoracic-spine MRIs were graded for the following 4 factors of degenerative changes: decrease in signal intensity of intervertebral disc (DSI), posterior disc protrusion (PDP), anterior compression of dura and spinal cord (AC), and disc-space narrowing (DSN) from T1-2 to T12-L1. We assessed associations between changes in MRI grade and demographical factors such as age, sex, body mass index, smoking habits, sports activities, and disc degeneration in the cervical spine. RESULTS: MRIs revealed that 63.1% of the subjects had degenerative changes in the thoracic intervertebral discs that had progressed at least one grade during the follow-up period. DSI progressed in 44.7% of subjects, PDP in 21.4%, and AC in 18.4% during the 10-year period. No DSN progression was seen. DSI was frequently observed in the upper thoracic spine (T1-2 to T4-5). Disc degeneration was relatively scarce in the lower thoracic spine (T9-10 to T12-L1). PDP was frequently observed in the middle thoracic spine (T5-6 toT8-9). We found significant associations between DSI and cervical-spine degeneration (P = .004) and between AC and smoking (P = .04). CONCLUSION: Progressive thoracic disc degeneration, observed in 63.1% of subjects; was significantly associated with smoking and with cervical-spine degeneration.2.

© 2018 Elsevier B.V. Objectives: : Functional venous anatomy in the brain has been mostly understood from the morphological and embryological points of view and no published study has directly evaluated the blood flow volume of cerebral small veins. We developed a method to directly evaluate the relative blood volume in small venous channels using multi-detector computed tomography (CT) and applied it to evaluate the blood volume in each tributary of the cavernous sinus, which plays an important role in cerebral venous drainage. Patients and Methods: : Ten patients with small brain tumors who had normal venous anatomy were included in the present study. All of them underwent preoperative 320-row multi-detector CT. After injecting the contrast bolus, we measured the Hounsfield units (HUs) at 10 time point over 60 s in each tributary of the cavernous sinus. The gamma distribution fitting to each HU enabled us to obtain a time-density curve and determine the relative venous volume in each venous channel. Results: : In terms of blood volume, the superficial middle cerebral vein and inferior petrosal sinus were the largest inflow and outflow channels of the cavernous sinus and accounted for 36.1% and 24.7% of its inflow and outflow on average, respectively. The superior orbital vein did not contribute to the blood volume passing through the cavernous sinus in the current study. Conclusions: : The present study allowed us to determine the relative blood volume in each tributary of the cavernous sinus, which was very useful to understand the physiological actual venous drainage pattern concerning the cavernous sinus in normal anatomy.

© 2018 Wolters Kluwer Health, Inc. All rights reserved. Study Design: A 20-year longitudinal study. Objective: To evaluate the long-term effect of sagittal alignment of the cervical spine on intervertebral disk degeneration in healthy asymptomatic subjects. Summary of Background Data: This study continues a previous 10-year longitudinal study to determine whether sagittal alignment affects disk degeneration during normal aging. Materials and Methods: We assessed 90 healthy subjects (30 men and 60 women) from among 497 volunteers who underwent magnetic resonance imaging (MRI) and plain radiographs of the cervical spine between 1994 and 1996 (follow-up rate 18.1%). The mean age at the initial study was 35.5 13.4 years (11-65 y). We compared initial MRIs and follow-up MRIs, conducted at an average of 21.6 years after the initial study, for (1) decreased signal intensity of the intervertebral disks, (2) posterior disk protrusion, and (3) disk-space narrowing from C2-3 to C7-T1. Subjects were grouped by age at follow-up (under 40 vs. 40 y and older) and by a lordotic or nonlordotic cervical sagittal alignment at baseline. We assessed neck pain, stiff shoulders, and upper-arm numbness at follow-up, and examined associations between clinical symptoms and MRI parameters. Results: Progressive changes during the 20-year period included a decrease in disk signal intensity (84.4% of subjects), posterior disk protrusion (86.7%), and disk-space narrowing (17.8%). No significant association was observed between sagittal alignment and decreased disk signal intensity, posterior disk protrusion, or disk-space narrowing. Among subjects over the age of 40, progressive degenerative changes at C7-T1 were significantly more frequent in nonlordotic subjects (90.9%) compared with those with cervical lordosis (54.2%, P= 0.032). The prevalence of clinical symptoms was similar in lordotic and nonlordotic subjects at follow-up. Conclusions: Nonlordotic cervical alignment was related to the progression of disk degeneration at C7-T1 but not other levels. Cervical alignment did not affect the development of clinical symptoms in healthy subjects.

The anti-VEGF antibody bevacizumab has shown efficacy for the treatment of neurofibromatosis type 2 (NF2). Theoretically, vascular endothelial growth factor receptors (VEGFRs)-specific cytotoxic T lymphocytes (CTLs) can kill both tumor vessel cells and tumor cells expressing VEGFRs. Here we show an exploratory clinical study of VEGFRs peptide vaccine in seven patients with progressive NF2-derived schwannomas. Hearing improves in 2/5 assessable patients (40%) as determined by international guidelines, with increases in word recognition scores. Tumor volume reductions of ≥20% are observed in two patients, including one in which bevacizumab had not been effective. There are no severe adverse events related to the vaccine. Both VEGFR1-specific and VEGFR2-specific CTLs are induced in six patients. Surgery is performed after vaccination in two patients, and significant reductions in the expression of VEGFRs in schwannomas are observed. Therefore, this clinical immunotherapy study demonstrates the safety and preliminary efficacy of VEGFRs peptide vaccination in patients with NF2.

Objective: The superficial middle cerebral vein (SMCV) is of clinical importance because of its contribution to the venous drainage of the superficial part of the cerebrum. Sphenoid ridge meningioma (SRM) grows adjacent to the SMCV and its drainage routes, and is thought to occasionally influence the hemodynamics of the SMCV, although this has seldom been suggested in the literature. We investigated the effect of SRM on the SMCV via blood flow analysis using multi-detector computed tomography. Patients and Methods: Overall, 22 patients with SRM who preoperatively underwent contrast-enhanced dynamic computed tomography at our institution were included in this study. We serially measured the Hounsfield units at each point of the SMCV and its adjacent veins on the side on which the tumor was located. We then obtained a time-density curve for each point via gamma distribution fitting. We determined the time-to-peak at each point by calculating the derivative of the time-density curve function and deduced the direction of blood passing through each vein by comparing the time-to-peak values between several points. Results: In total, 26 SMCVs were measured in 19 out of 22 cases. Of the 26 SMCVs, 16 were patent in the medial portion and contributed to normal venous drainage: 4 of them emptied into the cavernous sinus (CS), and 12 of them into the para-cavernous sinus (ParaCS). Out of the 10 that had their medial portions occluded because of the effects of the tumor, 6 SMCVs mainly drained into the vein of Labbé and/or the vein of Trolard retrogradely. However, in 2 of these, the small medial portions of the SMCVs near the occluded portion were maintained anterogradely by the collateral venous structures. In 4 SMCVs, the blood flow through the collateral veins remained anterograde; this was considered to contribute to normal venous drainage. Conclusion: The SRM is likely to cause occlusion or stenosis in the SMCV and influence its hemodynamics. In cases in which the connection between the SMCV and the CS or the ParaCS has been lost, the SMCV may still be involved in normal venous drainage via the collateral veins in some of those cases. Thus, the contribution of these veins to normal venous drainage in the brain should be analyzed preoperatively in careful detail.

We aimed to use upright computed tomography (CT) to depict posture-related changes in the brain tissue under normal gravity. Thirty-two asymptomatic volunteers underwent upright CT in the sitting position and conventional CT in the supine position on the same day. We compared the shift of the pineal body, cerebellar tonsil, the length of pituitary stalk, optic nerve sheath area and perimeter (ONSA and ONSP, respectively), and lateral ventricular volume between the supine and sitting positions. We also compared shape changes of the cerebrospinal fluid (CSF) spaces at different sites between both positions. In the sitting position, the pineal body shifted 0.68 ± 0.27 mm in the ventral direction and 0.76 ± 0.24 mm in the caudal direction, the length of pituitary stalk decreased by 1.23 ± 0.71 mm, the cerebellar tonsil descended by 2.10 ± 0.86 mm, the right ONSA decreased by 15.21 ± 6.54%, the left ONSA decreased by 15.30 ± 7.37%, the right ONSP decreased by 8.52 ± 3.91%, the left ONSP decreased by 8.20 ± 4.38%, and the lateral ventricular volume decreased by 5.07 ± 3.24% (all P < 0.001). We also observed changes in the shape of CSF spaces with changes in posture. We concluded that the intracranial structure of healthy subjects and volume of ventricles changed according to posture on Earth.

Background: Posterior fossa arachnoid cysts are often asymptomatic, but can rarely cause postural headache, the mechanism of which remains unknown. Case Description: We present a 40-year-old woman with an asymptomatic supracerebellar arachnoid cyst. Upright computed tomography (CT) showed enlargement of the arachnoid cyst and caudal descent of the cerebellum compared with supine CT with narrowing of the craniocervical junction cerebrospinal fluid space. Conclusions: This finding aids in understanding the association of posterior fossa arachnoid cysts with orthostatic headache. Clinicians should be aware of possible posture-related changes in intracranial structures.

Since the venous system is affected by gravity, upright computed tomography (CT) in addition to conventional supine CT has great potential for evaluating postural changes in the venous system. We evaluated the morphological differences in the head and neck vessels by performing a contrast CT study in both the supine and the sitting positions. In this study, the 20 included participants (10 men and 10 women) were healthy adults aged 30 to 55 years. The cross-sectional area of the cervical vessels, craniocervical junction veins, and intracranial vessels were obtained quantitatively. Venous sinuses and venous plexuses that were difficult to measure were evaluated qualitatively. The average change in areas from a supine to an upright posture was − 77.87 ± 15.99% (P < 0.0001) in the right internal jugular vein (IJV), − 69.42 ± 23.15% (P < 0.0001) in the left IJV, − 61.52 ± 12.81% (P < 0.0001) in the right external jugular vein (EJV), and − 58.91 ± 17.37% (P < 0.0001) in the left EJV. In contrast, the change in the anterior condylar vein (ACV) from a supine to an upright posture was approximately + 144% (P < 0.005) on the right side and + 110% (P < 0.05) on the left side. In addition, according to the qualitative analysis, the posterior venous structures including the anterior condylar confluence (ACC) of the craniocervical junction became more prominent in an upright posture. Despite these changes, the intracranial vessels showed almost no change between postures. From a supine to an upright position, the IJVs and EJVs above the heart collapsed, and venous channels including the ACCs and ACVs opened, switching the main cerebral venous drainage from the IJVs to the vertebral venous system. Upright head CT angiography can be useful for investigating physiological and pathophysiological hemodynamics of the venous system accompanying postural changes.

Sinking skin flap syndrome is a craniectomy complication characterized by new neurological dysfunction that typically worsens in the upright position and improves after cranioplasty. We present a 33-year-old man who experienced hemiparesis in the upright position after craniectomy. Upright computed tomography (CT) before cranioplasty showed a remarkable shift of the brain compared to supine CT. After cranioplasty, both symptoms and brain shift on CT resolved. Upright CT enables detection and objective evaluation of paradoxical herniation and midline shift that is not obvious on supine imaging modalities. Clinicians need to be aware of positional brain shift in postcraniectomy patients.

BACKGROUND: The basal vein of Rosenthal (BVR) is important in intracranial surgery, including skull base surgery. Here, we report a case of petroclival meningioma in which a BVR variant drained into the tentorial sinus. CASE DESCRIPTION: An asymptomatic 62-year-old man was found to have a left petroclival meningioma during a routine examination. A "sliding-thin-slab" maximum intensity projection (MIP) was generated preoperatively using three-dimensional computed tomographic venography. It showed that the BVR variant drained into the free edge of the tentorium around the tumor. The tumor was removed via an anterior transpetrosal approach (ATPA). It was totally resected and the vein was preserved with no detectable venous complications. CONCLUSION: To our knowledge, this is the first study to describe surgery using the ATPA and involving a BVR variant, in which the vein was successfully imaged preoperatively using sliding-thin-slab MIP.