Katsuyoshi Mineura

Changes of cerebral blood flow, and oxygen and glucose metabolism following radiochemotherapy of gliomas: a PET study.

The effects of radiochemotherapy on blood flow, blood volume, and consumption of oxygen and glucose in tumor tissue and normal brain were studied by positron emission tomography. Thirteen patients with cerebral gliomas were included, and they were examined before, during, and within approximately 1 month after the therapy. The 15O-labeled gas steady state inhalation and the 18F-fluorodeoxyglucose methods were used. After the therapy, glucose consumption and blood volume decreased (p less than 0.03) in the tumoral tissue. In the structurally (CT) normal gray matter, blood flow, blood volume, and oxygen consumption did not show any significant changes; oxygen extraction fraction, glucose consumption, and glucose extraction fraction, however, decreased significantly (p less than 0.05, less than 0.02, and less than 0.03, respectively).

Intramedullary spinal cord germinoma: case report and review of the literature.

We discuss the case of a patient with a recurring intramedullary spinal cord germinoma of the lower thoracic spinal cord, which was successfully excised. A primary intramedullary spinal cord germinoma is very rare, and only four other cases have been reported in the literature. All five cases are reviewed regarding the appearance of the germinomas, their neuroradiological features, and their histopathological findings. We also discuss treatment choices for germinomas of the spinal cord.

A consistent region of deletion on 1p36 in meningiomas: identification and relation to malignant progression.

We analyzed the genetic aberrations on chromosome arms 1p, 10q, and 14q, which are thought to be loci that include putative tumor suppressor genes in meningiomas. We initially conducted molecular genetic testing on a total of 72 tumors including 15 atypical and 8 anaplastic meningiomas using double-target fluorescence in situ hybridization. An incidence of deletion of 1p was observed in 16.3% of histologically benign, 86.7% of atypical, and 87.5% of anaplastic meningiomas. Microsatellite analysis for loss of heterozygosity on 1p, 10q, and 14q was performed in 15 tumors (6 benign, 6 atypical, and 3 anaplastic meningiomas). We detected alimited deleted region on 1p36 in two tumors and suggest a new consistent region of deletion at 1p36.21 approximately p23 distal to D1S507 and proximal to D1S214, which spans 8.21 megabases. In addition, loss of 10q was detected in two of three secondary atypical meningiomas, and loss of 14q in two of three primary anaplastic meningiomas. We suggest that one of the putative suppressor genes is located at 1p36.21 approximately p23, and that 10q loss may contribute to the malignant progression from benign to atypical meningiomas.

MR Imaging of Ventral Thalamic Nuclei

BACKGROUND AND PURPOSE: The Vim and VPL are important target regions of the thalamus for DBS. Our aim was to clarify the anatomic locations of the ventral thalamic nuclei, including the Vim and VPL, on MR imaging. MATERIALS AND METHODS: Ten healthy adult volunteers underwent MR imaging by using a 1.5T whole-body scanner. The subjects included 5 men and 5 women, ranging in age from 23 to 38 years, with a mean age of 28 years. The subjects were imaged with STIR sequences (TR/TE/TI = 3200 ms/15 ms/120 ms) and DTI with a single-shot echo-planar imaging technique (TR/TE = 6000 ms/88 ms, b-value = 2000 s/mm2). Tractography of the CTC and spinothalamic pathway was used to identify the thalamic nuclei. Tractography of the PT was used as a reference, and the results were superimposed on the STIR image, FA map, and color-coded vector map. RESULTS: The Vim, VPL, and PT were all in close contact at the level through the ventral thalamus. The Vim was bounded laterally by the PT and medially by the IML. The VPL was bounded anteriorly by the Vim, laterally by the internal capsule, and medially by the IML. The posterior boundary of the VPL was defined by a band of low FA that divided the VPL from the pulvinar. CONCLUSIONS: The ventral thalamic nuclei can be identified on MR imaging by using reference structures such as the PT and the IML.

Visualization of mRNA expression in CNS using 11C-labeled phosphorothioate oligodeoxynucleotide

Antisense phosphorothioate oligodeoxynucleotide for mRNA of glial fibrillary acidic protein (GFAP) was labeled with the positron emitter 11C and administered i.v. to rats bearing glioma, which were expected to exhibit active expression of GFAP. Antisense oligodeoxynucleotide was retained in tumor cells, yielding clear images of tumors, while the control 20% mismatch oligodeoxynucleotide and sense-strand oligodeoxynucleotide were not retained in tumor cells. Findings revealed sequence-specific binding of the antisense oligodeoxynucleotide to the GFAP mRNA. Our methods can be used directly for non-invasive imaging of human gene expression using PET, a frequently used method of clinical examination.

Multitensor Tractography Enables Better Depiction of Motor Pathways: Initial Clinical Experience Using Diffusion-Weighted MR Imaging with Standard b-Value

BACKGROUND AND PURPOSE: The purpose of this work was to test the feasibility of using high angular resolution diffusion imaging (HARDI)-based multitensor tractography to depict motor pathways in patients with brain tumors. MATERIALS AND METHODS: Ten patients (6 males and 4 females) with a mean age of 52 years (range, 9–77 years) were scanned using a 1.5T clinical MR unit. Single-shot echo-planar imaging was used for diffusion-weighted imaging (repetition time, 6000 ms; excitation time, 88 ms) with a diffusion-sensitizing gradient in 32 orientations and a b-value of 1000 s/mm2. Data postprocessing was performed using both the conventional single- and multitensor methods. The depiction rate of the 5 major components of the motor pathways, that is, the lower extremity, trunk, hand, face, and tongue, was assessed. RESULTS: Motor fibers on both lesional and contralesional sides were successfully depicted by both the single-tensor and multitensor techniques. However, with the single-tensor model, the depiction of motor pathways was typically limited to the fibers of trunk areas. With the multitensor technique, at least 4 of 5 major fiber bundles arising from the primary motor cortex could be identified. CONCLUSION: HARDI-based multitensor tractography using a standard b-value (1000 s/mm2) can depict the fiber tracts from the face and tongue regions of the primary motor cortex.

Moyamoya patients exhibit higher brain temperatures than normal controls.

The balance between heat production (metabolism) and heat removal (blood flow) helps in keeping the temperature of the brain constant. In patients with moyamoya disease, this balance may be disturbed. The purpose of this study was to assess the thermal pathophysiology of the brain in patients with moyamoya disease. The study included 12 consecutive patients with moyamoya disease and 10 controls. Temperature was measured by image postprocessing of diffusion-weighted images. Our noninvasive thermometry showed that the ventricular temperature of moyamoya disease patients was higher than that of normal controls. The mean temperature difference of 1.1°C between the two groups was significant. Patients with moyamoya disease tend to have elevated ventricular temperatures, which may represent a mismatch between cerebral metabolism and perfusion.

Gamma Knife surgery for patients with brainstem metastases

OBJECT Because brainstem metastases are not deemed resectable, stereotactic radiosurgery (SRS) is the only treatment modality expected to achieve a radical cure. The authors describe their treatment results, focusing particularly on how long patients can survive without neurological deterioration following SRS for brainstem metastases. METHODS This was an institutional review board-approved, retrospective cohort study in which the authors pulled from their database information on 2553 consecutive patients with brain metastases who underwent Gamma Knife surgery (GKS) at the Mito GammaHouse between July 1998 and July 2011. Among the 2553 patients, excluding cases in which there was meningeal dissemination, 200 cases of brainstem metastases (78 women and 122 men with a mean age of 64 years [range 36-86 years]) were identified and analyzed. The most common primary site was the lung (137 patients) followed by the gastrointestinal tract (24 patients), breast (17 patients), kidney (12 patients), and others (10 patients). Among the 200 patients, 15 patients (7.5%) harbored at least 2 tumors in the brainstem: 11 patients had 2 tumors, 2 patients had 3 tumors, and 1 patient each had 4 or 5 tumors. Therefore, a total of 222 tumors were irradiated. These 222 tumors were located in the pons (121 lesions), the midbrain (65 lesions), and the medulla oblongata (36 lesions). The mean and median tumor volumes were 1.3 and 0.2 cm(3) (range 0.005-10.7 cm(3)), and the median peripheral radiation dose was 18.0 Gy (range 12.0-25.0 Gy). RESULTS The overall median survival time (MST) was 6.0 months. Distribution of MSTs across Recursive Partitioning Analysis (RPA) classes showed that the MSTs were 9.4 months in Class I (20 patients), 6.0 months in Class II (171 patients), and 1.9 months in Class III (9 patients). Better Karnofsky Performance Scale score, single metastasis, and well-controlled primary tumor were significant predictive factors for longer survival. The neurological and qualitative survival rates were 90.8% and 89.2%, respectively, at 24 months post-GKS. Better KPS score and smaller tumor volume tended to be associated with prolonged qualitative survival. Follow-up imaging studies were available for 129 patients (64.5%). The tumor control rate was 81.8% at 24 months post-GKS. Smaller tumor volume tended to contribute to tumor control. CONCLUSIONS The present results indicate that GKS is effective in the treatment of brainstem metastases, particularly from the viewpoint of maintaining a good neurological condition in the patient.

Cerebral White Matter Lesions May Be Partially Reversible in Patients with Carotid Artery Stenosis

SUMMARY: Contrary to the common belief that age-related WMLs (also known as leukoaraiosis) are a progressive condition, a case of partial reversal of WMLs shortly after carotid artery stenting is described. A 75-year-old man presented with frequent TIAs, which were attributed to right ICA stenosis. He subsequently underwent successful carotid artery stenting. Follow-up MR imaging a week after the procedure showed improvement of WMLs in the right cerebral hemisphere. Pixel-by-pixel image analysis showed that the reversed WMLs tended to have higher λ1 and lower signal intensity on b = 0 images compared with nonreversed lesions, but by only approximately 10%.

Oxygen metabolism changes in patients with idiopathic normal pressure hydrocephalus before and after shunting operation.

Objective –  The present study revealed the changes in cerebral oxygen metabolism before and after ventriculo‐peritoneal shunt (VPS) using 15O positron emission tomography (15O‐PET).