Search Results

You are looking at 1 - 5 of 5 items for

  • Author or Editor: Masahiko Tosaka x
Clear All Modify Search
Free access

Kazuki Komiyama, Masahiko Tosaka, Hiroya Shimauchi-Ohtaki, Masanori Aihara, Tatsuya Shimizu and Yuhei Yoshimoto

OBJECTIVE

Head CT is sometimes performed immediately after minor head injury; however, which cases develop into chronic subdural hematoma (CSDH) remains unclear. Here, the authors retrospectively reviewed the rare cases of CSDH treated surgically in which early head CT had been performed after the initial head trauma.

METHODS

A total of 172 patients (133 male and 39 female, median age 76 years) underwent surgery for CSDH at Gunma University Hospital between April 2010 and December 2017. Among these patients were 23 who had visited Gunma University Hospital or a nearby hospital and had undergone head CT within 7 days after the initial head trauma. Characteristics of the initial head CT were examined to identify indicators of subsequent CSDH.

RESULTS

Among the 23 CSDH cases (17 male and 6 female, median age 80 years), CT scans were obtained on the day of the initial injury (day 0) in 19 cases (25 sides) and 1–7 days after injury in 12 cases (19 sides); scans were obtained during both periods in 8 cases (12 sides), so that a total of 44 sides were examined. These CT scans were divided into two groups according to when they were obtained; cases in which scans were taken during both periods were included in both groups. Head CT performed on the day of injury showed normal findings in 5 (20%) of 25 sides, thin subdural effusion (SDE) ≤ 6 mm in 16 (64%) of 25 sides, thick SDE > 6 mm in 3 (12%) of 25 sides, and acute subdural hematoma (ASDH) in 1 (4%) of 25 sides. CT from 1–7 days after trauma showed thick SDE in 9 (47%) of 19 sides, thin SDE in 8 (42%) of 19 sides, and ASDH in 2 (11%) of 19 sides. A high-density line in the lateral direction (onion skin–like) was found between the skull and the brain in 9 (35%) of 26 sides with SDE on initial CT 0–7 days after the injury.

CONCLUSIONS

ASDH was not a common cause of CSDH. Head CT at the time of trauma that precedes CSDH often showed SDE. Such SDE that precedes CSDH was often close to the detection limit of CT immediately after the injury but became more apparent from the day after the injury.

Restricted access

Masahiko Tosaka, Hideaki Kohga, Satoshi Kobayashi, Akira Zama, Masaru Tamura, Masami Murakami and Tomio Sasaki

Restricted access

Rei Yamaguchi, Masahiko Tosaka, Takaaki Miyagishima, Tadashi Osawa, Keishi Horiguchi, Fumiaki Honda and Yuhei Yoshimoto

OBJECTIVE

Visual acuity impairment due to sellar and suprasellar tumors is not fully understood. The relationship between these tumors and disturbance of visual function was examined using preoperative MRI.

METHODS

This study reviewed 93 consecutive patients with sellar and suprasellar tumors. Best-corrected visual acuity (BCVA) and visual impairment score (VIS) were used for estimation of visual impairments. Preoperative MR images were examined to obtain several values for estimation of chiasmatic compression. Additionally, the optic nerve–canal bending angle (ONCBA) was newly defined as the external angle formed by the optic nerve in the optic canal and the optic nerve in the intracranial subarachnoid space at the junction, using preoperative sagittal T2-weighted MR images.

RESULTS

The mean ONCBA was about the same on the right (44° ± 25°) and the left (44° ± 24°). Sagittal ONCBA was defined as large (> 45°) and moderate (≤ 45°) on each side. Preoperative VIS was found to be significantly worse if the right or left ONCBA (or both) was large (right side: ONCBA large [median 20, IQR 8–30] > ONCBA moderate [median 10, IQR 3–17], p = 0.003, Mann-Whitney U-test; left side: ONCBA large [median 22, IQR 9–30] > ONCBA moderate [median 10, IQR 2–16], p = 0.001). A large ONCBA showed a significant relationship with unfavorable ipsilateral BCVA (> logMAR, 0; right side, p = 0.001, left side, p = 0.001, chi-square test). The ONCBA had a positive correlation with ipsilateral BCVA (right: r = 0.297, p = 0.031; left: r = 0.451, p = 0.000, Pearson’s correlation coefficient). Preoperative BCVA was significantly lower on the same side in the large ONCBA group compared with the moderate ONCBA group (right side: large ONCBA 0.169 ± 0.333 [logMAR, mean ± standard deviation] vs moderate ONCBA 0.045 ± 0.359, p = 0.026, Student t-test; left side: large ONCBA 0.245 ± 0.346 vs moderate ONCBA 0.025 ± 0.333, p = 0.000). This visual acuity impairment improved after resection of the tumors.

CONCLUSIONS

Sagittal bending of the optic nerve at the entrance from the intracranial subarachnoid space to the optic canal may be related to ipsilateral deterioration of visual acuity in sellar and suprasellar lesions. Sagittal T2-weighted MRI is recommended for preoperative estimation of the optic nerve bending.

Restricted access

Masahiko Tosaka, Masaru Tamura, Noboru Oriuchi, Mieko Horikoshi, Takashi Joshita, Kenichi Sugawara, Satoshi Kobayashi, Hideaki Kohga, Takatomo Yoshida and Tomio Sasaki

✓ A 20-year-old man presented with slowly progressing symptoms indicative of increased intracranial pressure. Two weeks later he underwent surgery for placement of a ventriculoperitoneal shunt. Cytological examination of the patient's cerebrospinal fluid (CSF) revealed atypical cells that contained no detectable melanin deposits, but proved to be immunocytochemically positive for monoclonal antibodies to melanocytic cells (HMB-45) and S-100 protein. Dermatological and ophthalmological examinations failed to demonstrate any abnormalities. On the basis of these findings, a diagnosis of primary leptomeningeal melanoma was made. Gadolinium-enhanced magnetic resonance (MR) images of the brain and spinal regions obtained 2 months after admission demonstrated typical widespread leptomeningeal enhancement. Results of technetium-99m-hexakis (2-methoxyisobutyl isonitrile) single-photon emission computerized tomography (99mTc-MIBI SPECT) scanning revealed intense uptake of the isotope in the leptomeningeal regions and some cisterns. The patient's condition progressively worsened and he died 5 months after admission. The diagnosis was confirmed at autopsy.

Immunocytochemical analysis of CSF performed using HMB-45 and S-100 protein antibodies is important for the diagnosis of leptomeningeal melanoma because of the test's simplicity, high specificity, and sensitivity. Gadolinium-enhanced MR imaging is used to demonstrate the extent of the leptomeningeal melanoma. An additional and supplemental neuroimaging modality, 99mTc-MIBI SPECT scanning has good potential for the detection and diagnosis of leptomeningeal melanoma.