Toshiya Momose

PET pharmacokinetic analysis to estimate boron concentration in tumor and brain as a guide to plan BNCT for malignant cerebral glioma.

INTRODUCTION To plan the optimal BNCT for patients with malignant cerebral glioma, estimation of the ratio of boron concentration in tumor tissue against that in the surrounding normal brain (T/N ratio of boron) is important. We report a positron emission tomography (PET) imaging method to estimate T/N ratio of tissue boron concentration based on pharmacokinetic analysis of amino acid probes. METHODS Twelve patients with cerebral malignant glioma underwent 60 min dynamic PET scanning of brain after bolus injection of (18)F-borono-phenyl-alanine (FBPA) with timed arterial blood sampling. Using kinetic parameter obtained by this scan, T/N ratio of boron concentration elicited by one-hour constant infusion of BPA, as performed in BNCT, was simulated on Runge-Kutta algorithm. (11)C-methionine (MET) PET scan, which is commonly used in worldwide PET center as brain tumor imaging tool, was also performed on the same day to compare the image characteristics of FBPA and that of MET. RESULT PET glioma images obtained with FBPA and MET are almost identical in all patients by visual inspection. Estimated T/N ratio of tissue boron concentration after one-hour constant infusion of BPA, T/N ratio of FBPA on static condition, and T/N ratio of MET on static condition showed significant linear correlation between each other. CONCLUSION T/N ratio of boron concentration that is obtained by constant infusion of BPA during BNCT can be estimated by FBPA PET scan. This ratio can also be estimated by MET-PET imaging. As MET-PET study is available in many clinical PET center, selection of candidates for BNCT may be possible by MET-PET images. Accurate planning of BNCT may be performed by static images of FBPA PET. Use of PET imaging with amino acid probes may contribute very much to establish an appropriate application of BNCT for patients with malignant glioma.

Prognostic factors in patients with primary brainstem hemorrhage.

OBJECTIVE Primary brainstem hemorrhage (PBH) frequently causes severe disturbances of consciousness, papillary abnormalities, as well as respiratory and motor disturbances. The prognosis has been reported to be highly dependent on the clinical severity at presentation and the presence of certain radiological markers. However, the number of PBH patients enrolled in previous reports tended to be small, and precise statistical analyses were also lacking. The aim of this study was to analyze the impact of clinical or radiologic parameters on the outcome of patients with PBH. METHODS We retrospectively reviewed 212 consecutive patients with PBH and analyzed the impact of the clinical or radiological parameters on the outcome of patients with PBH. RESULTS Of the 212 patients, 134 (63.2%) were male and 78 (36.8%) were female, with an age range of 17-97 years (mean, 60.3 years). The median admission GCS score was 4. The outcomes included a good recovery in 13 patients (6.1%), moderate disability in 27 (12.7%), severe disability in 27 (12.7%), a vegetative state in 23 (10.8%), and death in 122 (57.5%). A multivariate analysis demonstrated bilateral hematoma extension, a GCS score ≤8, the presence of hydrocephalus, gender, and the hematoma volume to all be significantly associated with the 3-month mortality, while the GCS score ≤8, the presence of a pupillary abnormality, and the hematoma volume were found to be associated with the 3-month poor outcome. CONCLUSION The identification of these factors is therefore considered to be useful for managing patients with PBH.

Clinical benefit of 11C methionine PET imaging as a planning modality for radiosurgery of previously irradiated recurrent brain metastases.

Object Stereotactic radiosurgery with gamma knife (GK-SRS) generally improves the focal control of brain metastases. Yet in cases of focal recurrence at a previous radiation site, MRI is often imperfect in differentiating between active tumor and radiation injury. We have examined whether the use of 11C methionine (MET) with PET will facilitate this differentiation and improve the outcome of GK-SRS for focally recurrent brain metastases after prior treatment. Methods Eighty-eight patients underwent GK-SRS for postirradiation recurrent brain metastases. Thirty-four patients received radiation in areas manifesting high MET uptake (PET group) in a dose-planning procedure using MET-PET/MRI fusion images. Fifty-four patients referred from other institutes received radiation based on dose planning information obtained from MRI (MRI group). Results Sex, age, and the ratio of breast cancer differed significantly between the MRI and PET groups. The total irradiation volume was significantly smaller in the PET group, and the minimal irradiation dose was significantly higher. In a multivariable statistical analysis, the use of MET-PET (P = 0.02) was independently associated with prolonged overall survival after treatment, Karnofsky performance status (P = 0.002), the number of lesions (P = 0.03), and patient’s sex (P = 0.02). The median survival time was significantly longer in the PET group (18.1 months) than in the MRI group (8.6 months) (P = 0.01). Conclusion 11C methionine-PET/MRI fusion images for dose planning lengthened survival in patients undergoing GK-SRS for focally recurrent brain metastases.

Chronologic Evaluation of Cerebral Hemodynamics by Dynamic Susceptibility Contrast Magnetic Resonance Imaging After Indirect Bypass Surgery for Moyamoya Disease

OBJECTIVE Although indirect bypass surgery is an effective treatment option for patients with ischemic-onset moyamoya disease (MMD), the time point after surgery at which the patients hemodynamic status starts to improve and the time point at which the improvement reaches a maximum have not been known. The objective of the present study is to evaluate the hemodynamic status time course after indirect bypass surgery for MMD, using dynamic susceptibility contrast-magnetic resonance imaging (DSC-MRI). METHODS We retrospectively analyzed the cases of 25 patients with MMD (37 sides; mean age, 14.7 years; range, 3-36 years) who underwent indirect bypass surgery and repeated DSC-MRI measurement within 6 months after the operation. The difference in the mean transit time (MTT) between the target regions and the control region (cerebellum) was termed the MTT delay, and we measured the MTT delays chronologic changes after surgery. RESULTS The postoperative MTT delay was 1.81 ± 1.16 seconds within 1 week after surgery, 1.57 ± 1.01 at weeks 1-2, 1.55 ± 0.68 at weeks 2-4, 1.32 ± 0.68 at months 1-2, 0.95 ± 0.32 at months 2-3, and 0.77 ± 0.33 at months 3-6. Compared with the preoperative value (2.11 ± 0.98 seconds), the MTT delay decreased significantly from 2 to 4 weeks after surgery (P < 0.05). CONCLUSIONS The amelioration of cerebral hemodynamics by indirect bypass surgery began soon after surgery and gradually reached a maximum at 3 months after surgery. DSC-MRI detected small changes in hemodynamic improvement, which are suspected to be caused by the initiation of angiogenesis and arteriogenesis in the early postoperative period.

Computed tomography after decompressive craniectomy for head injury.

New findings (NF) on postoperative CTs are -occasionally found in patients who undergo surgery for traumatic brain injury (TBI). We conducted a retrospective -registry-based review of the care of 102 patients who underwent decompressive craniectomy (DC) for TBI to investigate the prognostic factors of new findings on CT early after -surgery. Of the 102 patients, the mean age was 50 years and 69.6 % were male. The overall survival was 72.5 %. The primary indication for DC included subdural hematoma in 72 (70.6 %), epidural hematoma in 17 (16.7 %), and intraparenchymal contusion in 13 (12.7 %). New findings on postoperative CTs were observed in 26 patients (25.5 %). The univariate analysis showed that a GCS score ≤8 (P = 0.012) and the absence of a basal cistern (P = 0.012) were significantly associated with NF on postoperative CT. The logistic regression analysis demonstrated that the GCS score ≤8 (P = 0.041; OR, 3.0; 95 % CI, 1.048-8.517) was the only significant factor. TBI patients with a low GCS score who underwent DC should undergo additional CT evaluations immediately after surgery.

Outcome of traumatic brain injury in patients on antiplatelet agents: a retrospective 20-year observational study in a single neurosurgery unit

ABSTRACT Objective: To evaluate the outcomes after Traumatic Brain Injury (TBI) in patients taking Antiplatelet Agents (APAs). Methods: We reviewed the clinical records of 934 patients with TBI between 1995 and 2014. Multivariate analysis was performed to correlate patient outcome with various factors, including pre-injury APA intake. Cause of death was compared among groups stratified according to APA dose. Results: Increasing doses of APAs were positively associated with mortality rates, however, differences were primarily due to non-traumatic causes. APA therapy before injury was independent of both overall and non-traumatic mortality. In multivariate analysis, mortality was significantly correlated with the Charlson Comorbidity Index (CCI), pupillary abnormalities, age, Glasgow Coma Scale (GCS), head Abbreviated Injury Scale (AIS) and additional AIS >2. Conversely, non-traumatic mortality was associated with age, GCS, additional AIS >2 and CCI, though only CCI was correlated with increasing APA dose. Furthermore, no significant difference was observed when comparing mortalities according to CCI score among APA groups. Thus, mortalities were associated with the severity of pre-existing conditions rather than APA dose. Conclusions: The outcome of patients with TBI, who were on APAs may be determined by the severity of pre-existing conditions. Aggressive TBI treatment should be implemented when tolerable, regardless of pre-existing APA treatment status.