Search Results

You are looking at 1 - 9 of 9 items for

  • Author or Editor: Tetsuya Yamamoto x
Clear All Modify Search
Full access

Satoru Osuka, Akira Matsushita, Tetsuya Yamamoto, Kousaku Saotome, Tomonori Isobe, Yasushi Nagatomo, Tomohiko Masumoto, Yoji Komatsu, Eiichi Ishikawa and Akira Matsumura

Object

Ventriculomegaly is a common imaging finding in many types of conditions. It is difficult to determine whether it is related to true hydrocephalus or to an atrophic process by using only imaging procedures such as MR imaging after traumatic injury, stroke, or infectious disease. Diffusion tensor (DT) imaging can distinguish the compression characteristics of white matter, indicating that increased diffusion anisotropy may be related to white matter compression. In this preliminary study, the authors compared the DT imaging findings of ventriculomegaly with those of chronic hydrocephalus or atrophy to clarify the potential of diffusion anisotropy in the identification of hydrocephalus.

Methods

Ten patients with chronic hydrocephalus, 8 patients with atrophy (defined by conventional devices and surgical outcome), and 14 healthy volunteers underwent DT imaging. Images were acquired before and after shunting or once in cases without shunting. The fractional anisotropy (FA) values at many points around the lateral ventricle were evaluated.

Results

The FA patterns around the lateral ventricle in the chronic hydrocephalus and atrophy groups were different. Especially in the caudate nucleus, FA was increased in the chronic hydrocephalus group compared with the atrophy group. Furthermore, the FA values returned to normal levels after shunt placement.

Conclusions

Assessment of the FA value of the caudate nucleus may be an important, less invasive method for distinguishing true hydrocephalus from ventriculomegaly. Further research in a large number of patients is needed to verify the diagnostic ability of this method.

Full access

Yoshihiro Muragaki, Takashi Maruyama, Hiroshi Iseki, Masahiko Tanaka, Chie Shinohara, Kintomo Takakura, Koji Tsuboi, Tetsuya Yamamoto, Akira Matsumura, Masao Matsutani, Katsuyuki Karasawa, Katsunori Shimada, Naohito Yamaguchi, Yoichi Nakazato, Keiki Sato, Youji Uemae, Tadao Ohno, Yoshikazu Okada and Tomokatsu Hori

Object

The objective of the present study was analysis of results of the prospective clinical trial directed toward the evaluation of therapeutic efficacy of the administration of autologous formalin-fixed tumor vaccine (AFTV) concomitant with fractionated radiotherapy in cases of newly diagnosed glioblastoma multiforme.

Methods

Twenty-four patients were enrolled into the clinical trial, while 2 cases were excluded from the final analysis of results. The treatment protocol included aggressive tumor resection, fractionated radiotherapy up to a total dose of 60 Gy, and 3 concomitant courses of AFTV administered with an interval of one week at the late stage of irradiation. Two delayed-type hypersensitivity (DTH) tests were done—one 48 hours before the initial course of vaccination (DTH-1) and one 2 weeks after the third (DTH-2). All but one of the patients received salvage therapy at the time of tumor progression. The defined primary end point was overall survival; secondary end points were progression-free survival and safety of concomitant treatment.

Results

The median duration of overall survival was 19.8 months (95% CI 13.8–31.3 months). The actuarial 2-year survival rate was 40%. The median duration of progression-free survival was 7.6 months (95% CI 4.3–13.6 months). Overall survival showed a statistically significant association with recursive partitioning analysis class (p < 0.05); progression-free survival showed a statistically significant association with p53 staining index (p < 0.05) and size of DTH-2 response (p < 0.001). AFTV injection concomitant with fractionated radiotherapy was well tolerated by all patients and in no case did treatment-related adverse effects exceed Grade 1 toxicity; adverse effects were limited to local erythema, induration, and swelling at the site of injection.

Conclusions

The results of this study demonstrate that AFTV treatment concomitant with fractionated radiotherapy may be effective in patients with newly diagnosed glioblastoma. Further clinical testing is warranted.

Full access

Satoru Osuka, Akira Matsushita, Eiichi Ishikawa, Kousaku Saotome, Tetsuya Yamamoto, Aiki Marushima, Naoaki Satou, Alexander Zaboronok, Tomohiko Masumoto and Akira Matsumura

Object

For several decades, clinicians have predicted intraparenchymal brain pressure or brain tissue compression indirectly based on the degree of distortion of the midline structures (midline shift) and ventricle wall (ventriculomegaly) observed on conventional MRI. However, this method has several limitations. Diffusion tensor imaging (DTI) is a novel MRI technique that can provide information about the microstructural properties of compressed tissue. In this study, the authors evaluated whether DTI can precisely define the degree of tissue compression in patients with chronic subdural hematoma (CSDH).

Methods

The study sample consisted of 18 patients (mean age 71 years, 10 men and 8 women) with unilateral CSDH and 12 age-matched volunteers. Diffusion tensor imaging results were acquired before and after the surgical irrigation in the CSDH group. Subdural pressure during the operation was also measured. Fractional anisotropy (FA) values were evaluated at several locations, including the gray matter.

Results

The FA values of the gray matter, especially in the caudate nucleus and putamen, were increased in the patients with CSDH compared with the control group. The change in FA data before and after surgery (ΔFA) correlated with the degree of tissue compression evaluated by measurement of the subdural pressure. Furthermore, the increased FA values in patients with CSDH decreased after surgery.

Conclusions

These findings indicate that FA values of the gray matter, especially in the caudate nucleus and putamen, may be important markers of tissue compression. The assessment of FA values of the gray matter will result in a new, less-invasive diagnostic technique to evaluate the degree of brain compression.

Full access

Eiichi Ishikawa, Yoshihiro Muragaki, Tetsuya Yamamoto, Takashi Maruyama, Koji Tsuboi, Soko Ikuta, Koichi Hashimoto, Youji Uemae, Takeshi Ishihara, Masahide Matsuda, Masao Matsutani, Katsuyuki Karasawa, Yoichi Nakazato, Tatsuya Abe, Tadao Ohno and Akira Matsumura

Object

Temozolomide (TMZ) may enhance antitumor immunity in patients with glioblastoma multiforme (GBM). In this paper the authors report on a prospective Phase I/IIa clinical trial of fractionated radiotherapy (FRT) concomitant with TMZ therapy, followed by treatment with autologous formalin-fixed tumor vaccine (AFTV) and TMZ maintenance in patients with newly diagnosed GBM.

Methods

Twenty-four patients (age 16–75 years, Karnofsky Performance Scale score ≥ 60% before initiation of FRT) with newly diagnosed GBM received a total dose of 60 Gy of FRT with daily concurrent TMZ. After a 4-week interval, the patients received 3 AFTV injections and the first course of TMZ maintenance chemotherapy for 5 days, followed by multiple courses of TMZ for 5 days in each 28-day cycle.

Results

This treatment regimen was well tolerated by all patients. The percentage of patients with progression-free survival (PFS) ≥ 24 months was 33%. The median PFS, median overall survival (OS), and the actuarial 2- and 3-year survival rates of the 24 patients were 8.2 months, 22.2 months, 47%, and 38%, respectively. The median PFS in patients with a delayed-type hypersensitivity (DTH) response after the third AFTV injection (DTH-2) of 10 mm or larger surpassed the median length of follow-up for progression-free patients (29.5 months), which was significantly greater than the median PFS in patients with a smaller DTH-2 response.

Conclusions

The treatment regimen was well tolerated and resulted in favorable PFS and OS for newly diagnosed GBM patients. Clinical trial registration no.: UMIN000001426 (UMIN clinical trials registry, Japan).

Full access

Shinya Watanabe, Masaaki Yamamoto, Yasunori Sato, Takuya Kawabe, Yoshinori Higuchi, Hidetoshi Kasuya, Tetsuya Yamamoto, Akira Matsumura and Bierta E. Barfod

Object

Recently, an increasing number of patients with brain metastases, even patients over 80 years of age, have been treated with stereotactic radiosurgery (SRS). However, there is little information on SRS treatment results for patients with brain metastases 80 years of age and older. The authors undertook this study to reappraise whether SRS treatment results for patients 80 years of age or older differ from those of patients who are 65–79 years old.

Methods

This was an institutional review board–approved, retrospective cohort study. Among 2552 consecutive brain metastasis patients who underwent SRS during the 1998–2011 period, we studied 165 who were 80 years of age or older (Group A) and 1181 who were age 65–79 years old (Group B). Because of the remarkable disproportion in patient numbers between the 2 groups and considerable differences in pre-SRS clinical factors, the authors conducted a case-matched study using the propensity score matching method. Ultimately, 330 patients (165 from each group, A and B) were selected. For time-to-event outcomes, the Kaplan-Meier method was used to estimate overall survival and competing risk analysis was used to estimate other study end points, as appropriate.

Results

Although the case-matched study showed that post-SRS median survival time (MST, months) was shorter in Group A patients (5.3 months, 95% CI 3.9–7.0 months) than in Group B patients (6.9 months, 95% CI 5.0–8.1 months), this difference was not statistically significant (HR 1.147, 95% CI 0.921–1.429, p = 0.22). Incidences of neurological death and deterioration were slightly lower in Group A than in Group B patients (6.3% vs 11.8% and 8.5% vs 13.9%), but these differences did not reach statistical significance (p = 0.11 and p = 0.16). Furthermore, competing risk analyses showed that the 2 groups did not differ significantly in cumulative incidence of local recurrence (HR 0.830, 95% CI 0.268–2.573, p = 0.75), rates of repeat SRS (HR 0.738, 95% CI 0.438–1.242, p = 0.25), or incidence of SRS-related complications (HR 0.616, 95% CI 0.152–2.495, p = 0.49). Among the Group A patients, post-SRS MSTs were 11.6 months (95% CI 7.8–19.6 months), 7.9 months (95% CI 5.2–10.9 months), and 2.8 months (95% CI; 2.4–4.6 months) in patients whose disease status was modified–recursive partitioning analysis (RPA) Class(es) I+IIa, IIb, and IIc+III, respectively (p < 0.001).

Conclusions

Our results suggest that patients 80 years of age or older are not unfavorable candidates for SRS as compared with those 65–79 years old. Particularly, even among patients 80 years and older, those with modified-RPA Class I+IIa or IIb disease are considered to be favorable candidates for more aggressive treatment of brain metastases.

Free access

Takao Koiso, Masaaki Yamamoto, Takuya Kawabe, Shinya Watanabe, Yasunori Sato, Yoshinori Higuchi, Tetsuya Yamamoto, Akira Matsumura and Hidetoshi Kasuya

OBJECTIVE

Stereotactic radiosurgery (SRS) without upfront whole-brain radiotherapy (WBRT) has influenced recent treatment recommendations for brain metastasis patients. However, in brain metastasis patients who undergo SRS alone, new brain metastases inevitably appear with relatively high incidences during post-SRS follow-up. However, little is known about the second SRS results. The treatment results of second SRS were retrospectively reviewed, mainly for newly developed or, uncommonly, for recurrent brain metastases in order to reappraise the efficacy of this treatment strategy with a special focus on the maintenance of neurological status and safety.

METHODS

This was an institutional review board–approved, retrospective cohort study that used a prospectively accumulated database, including 3102 consecutive patients with brain metastases who underwent SRS between July 1998 and June 2015. Among these 3102 patients, 859 (376 female patients; median age 64 years; range 21–88 years) who underwent a second SRS without WBRT were studied with a focus on overall survival, neurological death, neurological deterioration, local recurrence, salvage SRS, and SRS-induced complications after the second SRS. Before the second SRS, the authors also investigated the clinical factors and radiosurgical parameters likely to influence these clinical outcomes. For the statistical analysis, the standard Kaplan-Meier method was used to determine post–second SRS survival and neurological death. A competing risk analysis was applied to estimate post–second SRS cumulative incidences of local recurrence, neurological deterioration, salvage SRS, and SRS-induced complications.

RESULTS

The post–second SRS median survival time was 7.4 months (95% CI 7.0–8.2 months). The actuarial survival rates were 58.2% and 34.7% at 6 and 12 months after the second SRS, respectively. Among 789 deceased patients, the causes of death could not be determined in 24 patients, but were confirmed in the remaining 765 patients to be nonbrain diseases in 654 (85.5%) patients and brain diseases in 111 (14.5%) patients. The actuarial neurological death–free survival rates were 94.4% and 86.6% at 6 and 12 months following the second SRS. Multivariable analysis revealed female sex, Karnofsky Performance Scale score of 80% or greater, better modified recursive partitioning analysis class, smaller tumor numbers, and higher peripheral dose to be significant predictive factors for longer survival. The cumulative incidences of local recurrence were 11.2% and 14.9% at 12 and 24 months after the second SRS. The crude incidence of neurological deterioration was 7.1%, and the respective cumulative incidences were 4.5%, 5.8%, 6.7%, 7.2%, and 7.5% at 12, 24, 36, 48, and 60 months after the second SRS. SRS-induced complications occurred in 25 patients (2.9%) after a median post–second SRS period of 16.8 months (range 0.6–95.0 months; interquartile range 5.6–29.3 months). The cumulative incidences of complications were 1.4%, 2.0%, 2.4%, 3.0%, and 3.0% at 12, 24, 36, 48, and 60 months after the second SRS, respectively.

CONCLUSIONS

Carefully selected patients with recurrent tumors—either new or locally recurrent—are favorable candidates for a second SRS, particularly in terms of neurological status maintenance and the safety of this treatment strategy.

Free access

Shinya Watanabe, Masaaki Yamamoto, Takuya Kawabe, Takao Koiso, Tetsuya Yamamoto, Akira Matsumura and Hidetoshi Kasuya

OBJECTIVE

The aim of this study was to reappraise long-term treatment outcomes of stereotactic radiosurgery (SRS) for vestibular schwannomas (VSs). The authors used a database that included patients who underwent SRS with a unique dose-planning technique, i.e., partial tumor coverage designed to avoid excess irradiation of the facial and cochlear nerves, focusing on tumor control and hearing preservation. Clinical factors associated with post-SRS tumor control and long-term hearing preservation were also analyzed.

METHODS

This institutional review board–approved, retrospective cohort study used the authors' prospectively accumulated database. Among 207 patients who underwent Gamma Knife SRS for VSs between 1990 and 2005, 183 (who were followed up for at least 36 post-SRS months) were studied. The median tumor volume was 2.0 cm3 (range 0.05–26.2 cm3). The median prescribed dose at the tumor periphery was 12.0 Gy (range 8.8–15.0 Gy; 12.0 Gy was used in 171 patients [93%]), whereas tumor portions facing the facial and cochlear nerves were irradiated with 10.0 Gy. As a result, 72%–99% of each tumor was irradiated with the prescribed dose. The mean cochlear doses ranged from 2.3 to 5.7 Gy (median 4.1 Gy).

RESULTS

The median durations of imaging and audiometric follow-up were 114 months (interquartile range 73–144 months) and 59 months (interquartile range 33–109 months), respectively. Tumor shrinkage was documented in 110 (61%), no change in 48 (27%), and enlargement in the other 22 (12%) patients. A further procedure (FP) was required in 15 (8%) patients. Thus, the tumor growth control rate was 88% and the clinical control rate (i.e., no need for an FP) was 92%. The cumulative FP-free rates were 96%, 93%, and 87% at the 60th, 120th, and 180th post-SRS month, respectively. Six (3%) patients experienced facial pain, and 2 developed transient facial palsy. Serviceable hearing was defined as a pure tone audiogram result better than 50 dB. Among the 66 patients with serviceable hearing before SRS who were followed up, hearing acuity was preserved in 23 (35%). Actuarial serviceable hearing preservation rates were 49%, 24%, and 12% at the 60th, 120th, and 180th post-SRS month, respectively. On univariable analysis, only cystic-type tumor (HR 3.36, 95% CI 1.18–9.36; p = 0.02) was shown to have a significantly unfavorable association with FP. Multivariable analysis followed by univariable analysis revealed that higher age (≥ 65 years: HR 2.66, 95% CI 1.16–5.92; p = 0.02), larger tumor volume (≥ 8 cm3: HR 5.36, 95% CI 1.20–17.4; p = 0.03), and higher cochlear dose (mean cochlear dose > 4.2 Gy: HR 2.22, 95% CI 1.07–4.77; p = 0.03) were unfavorable factors for hearing preservation.

CONCLUSIONS

Stereotactic radiosurgery achieved good long-term results in this series. Tumor control was acceptable, and there were few serious complications in patients with small- to medium-sized VSs. Unfortunately, hearing preservation was not satisfactory. However, the longer the observation period, the more important it becomes to compare post-SRS hearing decreases with the natural decline in untreated cases.

Full access

Yosuke Masuda, Hiroyoshi Akutsu, Eiichi Ishikawa, Masahide Matsuda, Tomohiko Masumoto, Takashi Hiyama, Tetsuya Yamamoto, Hidehiro Kohzuki, Shingo Takano and Akira Matsumura

OBJECTIVE

MRI scans obtained within 48–72 hours (early postoperative MRI [epMRI]), prior to any postoperative reactive changes, are recommended for the accurate assessment of the extent of resection (EOR) after glioma surgery. Diffusion-weighted imaging (DWI) enables ischemic lesions to be detected and distinguished from the residual tumor. Prior studies, however, revealed that postoperative reactive changes were often present, even in epMRI. Although intraoperative MRI (iMRI) is widely used to maximize safe resection during glioma surgery, it is unclear whether iMRI is superior to epMRI when evaluating the EOR, because it theoretically shows fewer postoperative reactive changes. In addition, the ability to detect ischemic lesions using iMRI has not been investigated.

METHODS

The authors retrospectively analyzed prospectively collected data in 30 patients with glioma (22 and 8 patients with enhancing and nonenhancing lesions, respectively) who underwent tumor resection. These patients had received preoperative MRI within 24 hours prior to surgery, postresection radiological evaluation with iMRI during surgery, and epMRI within 24 hours after surgery, with all neuroimaging performed using identical 1.5T MRI scanners. The authors compared iMRI or epMRI with preoperative MRI, and defined a postoperative reactive change as a new postoperative enhancement or T2 high-intensity area (HIA), if this lesion was outside of the preoperative original tumor location. In addition, postoperative ischemia was evaluated on DWI. The iMRI and epMRI findings were compared in terms of 1) postoperative reactive changes, 2) evaluation of the EOR, and 3) presence of ischemic lesion on DWI.

RESULTS

In patients with enhancing lesions, a new enhancement was seen in 8 of 22 patients (36.4%) on iMRI and in 12 of 22 patients (54.5%) on epMRI. In patients with nonenhancing lesions, a new T2 HIA was seen in 4 of 8 patients (50.0%) on iMRI and in 7 of 8 patients (87.5%) on epMRI. A discrepancy between the EOR measured on iMRI and epMRI was noted in 5 of the 22 patients (22.7%) with enhancing lesions, and in 3 of the 8 patients (37.5%) with nonenhancing lesions. The occurrence of ischemic lesions on DWI was found in 5 of 30 patients (16.7%) on iMRI, whereas it was found in 16 of 30 patients (53.3%) on epMRI (p = 0.003); ischemic lesions were underestimated on iMRI in 11 patients.

CONCLUSIONS

Overall, given the lower incidence of postoperative reactive changes on iMRI, it was superior to epMRI in evaluating the EOR in patients with glioma, both with enhancing and nonenhancing lesions. However, because ischemic lesions can be overlooked on iMRI, the authors recommend only the additional DWI scan during the early postoperative period. Clinicians need to be mindful about not overestimating the presence of residual tumor on epMRI due to the high incidence of postoperative reactive changes.

Free access

Hitoshi Aiyama, Masaaki Yamamoto, Takuya Kawabe, Shinya Watanabe, Takao Koiso, Yasunori Sato, Yoshinori Higuchi, Eiichi Ishikawa, Tetsuya Yamamoto, Akira Matsumura and Hidetoshi Kasuya

OBJECTIVE

Although the conformity index (CI) and the gradient index (GI), which were proposed by Paddick and colleagues, are both logically considered to correlate with good posttreatment results after stereotactic radiosurgery (SRS), this hypothesis has not been confirmed clinically. The authors’ aim was to reappraise whether high CI values correlate with reduced tumor progression rates, and whether low GI values correlate with reduced complication incidences.

METHODS

This was an institutional review board–approved, retrospective cohort study conducted using a prospectively accumulated database including 3271 patients who underwent Gamma Knife SRS for brain metastases (BMs) during the 1998–2016 period. Among the 3271 patients, 925 with a single BM at the time of SRS (335 women and 590 men, mean age 66 [range 24–93] years) were studied. The mean/median CIs were 0.62/0.66 (interquartile range [IQR] 0.53–0.74, range 0.08–0.88) and the mean/median GIs were 3.20/3.09 (IQR 2.83–3.39, range 2.27–11.4).

RESULTS

SRS-related complications occurred in 38 patients (4.1%), with a median post-SRS interval of 11.5 (IQR 6.0–25.8, maximum 118.0) months. Cumulative incidences of post-SRS complications determined by a competing risk analysis were 2.2%, 3.2%, 3.6%, 3.8%, and 3.9% at the 12th, 24th, 36th, 48th, and 60th post-SRS month, respectively. Multivariable analyses showed that only two clinical factors (i.e., peripheral doses and brain volume receiving ≥ 12 Gy) correlated with complication rates. However, neither CIs nor GIs impacted the incidences of complications. Among the 925 patients, post-SRS MRI was performed at least once in 716 of them, who were thus eligible for local progression evaluation. Among these 716 patients, local progression was confirmed in 96 (13.4%), with a median post-SRS interval of 10.8 (IQR 6.7–19.5, maximum 59.8) months. Cumulative incidences of local progression determined by a competing risk analysis were 7.7%, 12.6%, 14.2%, 14.8%, and 15.3% at the 12th, 24th, 36th, 48th, and 60th post-SRS month, respectively. Multivariable analyses showed neurological symptoms, extracerebral metastases, repeat SRS, and CIs to correlate with incidences of local progression, whereas GIs had no impact on local tumor progression. Particularly, cumulative incidences of local progression were significantly lower in patients with CIs < 0.65 than in those with CIs ≥ 0.65 (adjusted hazard ratio 1.870, 95% confidence interval 1.299–2.843; p = 0.0034).

CONCLUSIONS

To the authors’ knowledge, this is the first analysis to focus on the clinical significance of CI and GI based on a large series of patients with BM. Contrary to the majority opinion that dose planning with higher CI and lower GI results in good post-SRS outcomes (i.e., low local progression rates and minimal complications), this study clearly showed that the lower the CIs were, the lower the local progression rates were, and that the GI did not impact complication rates.