Satoru Ide

Stereotactic body radiotherapy for lung tumors in patients with subclinical interstitial lung disease: The potential risk of extensive radiation pneumonitis

PURPOSE To evaluate the toxicity and efficacy of thoracic stereotactic body radiotherapy (SBRT) in patients with subclinical interstitial lung disease (ILD). METHODS AND MATERIALS One hundred patients with 124 lung tumors were treated with SBRT at our institution according to our own protocols; patients with subclinical (untreated and oxygen-free) ILD were treated with SBRT, while those with clinical ILD (post- or under treatment) were not. The administration of 48 Gy in four fractions was used in 103 (83%) of the 124 tumors. The presence of subclinical ILD in the pre-SBRT CT findings was reviewed by two chest radiologists. The relationships between radiation pneumonitis (RP) and clinical factors were investigated. RESULTS Subclinical ILD was recognized in 16 (16%) of 100 patients. Grade 2-5 RP was recognized in 13 (13%) of 100 patients. Grade 2-5 RP was observed in three (19%) of 16 patients with subclinical ILD. Subclinical ILD was not found to be a significant factor influencing Grade 2-5 RP; however, extensive RP beyond the irradiated field, including the contralateral lung, was recognized in only three patients with subclinical ILD, and the rate of extensive RP was significantly high in the patients with subclinical ILD. Grade 4 or 5 extensive RP was recognized in only two patients with subclinical ILD. Dosimetric factors of the lungs (V5, V10, V15, V20, V25, MLD) were significantly associated with Grade 2-5 RP. The three-year overall survival and local control rates of all patients were 53% and 86%, respectively. No significant differences were seen in either overall survival or local control rates between the patients with ILD and those without ILD. CONCLUSIONS Subclinical ILD was not found to be a significant factor for Grade 2-5 RP or clinical outcomes in the current study; however, uncommon extensive RP can occur in patients with subclinical ILD.

Usefulness of Quantitative Susceptibility Mapping for the Diagnosis of Parkinson Disease

BACKGROUND AND PURPOSE: Quantitative susceptibility mapping allows overcoming several nonlocal restrictions of susceptibility-weighted and phase imaging and enables quantification of magnetic susceptibility. We compared the diagnostic accuracy of quantitative susceptibility mapping and R2* (1/T2*) mapping to discriminate between patients with Parkinson disease and controls. MATERIALS AND METHODS: For 21 patients with Parkinson disease and 21 age- and sex-matched controls, 2 radiologists measured the quantitative susceptibility mapping values and R2* values in 6 brain structures (the thalamus, putamen, caudate nucleus, pallidum, substantia nigra, and red nucleus). RESULTS: The quantitative susceptibility mapping values and R2* values of the substantia nigra were significantly higher in patients with Parkinson disease (P < .01); measurements in other brain regions did not differ significantly between patients and controls. For the discrimination of patients with Parkinson disease from controls, receiver operating characteristic analysis suggested that the optimal cutoff values for the substantia nigra, based on the Youden Index, were >0.210 for quantitative susceptibility mapping and >28.8 for R2*. The sensitivity, specificity, and accuracy of quantitative susceptibility mapping were 90% (19 of 21), 86% (18 of 21), and 88% (37 of 42), respectively; for R2* mapping, they were 81% (17 of 21), 52% (11 of 21), and 67% (28 of 42). Pair-wise comparisons showed that the areas under the receiver operating characteristic curves were significantly larger for quantitative susceptibility mapping than for R2* mapping (0.91 versus 0.69, P < .05). CONCLUSIONS: Quantitative susceptibility mapping showed higher diagnostic performance than R2* mapping for the discrimination between patients with Parkinson disease and controls.

Abnormal White Matter Integrity in the Corpus Callosum among Smokers: Tract-Based Spatial Statistics

In the present study, we aimed to investigate the difference in white matter between smokers and nonsmokers. In addition, we examined relationships between white matter integrity and nicotine dependence parameters in smoking subjects. Nineteen male smokers were enrolled in this study. Eighteen age-matched non-smokers with no current or past psychiatric history were included as controls. Diffusion tensor imaging scans were performed, and the analysis was conducted using a tract-based special statistics approach. Compared with nonsmokers, smokers exhibited a significant decrease in fractional anisotropy (FA) throughout the whole corpus callosum. There were no significant differences in radial diffusivity or axial diffusivity between the two groups. There was a significant negative correlation between FA in the whole corpus callosum and the amount of tobacco use (cigarettes/day; R = − 0.580, p = 0.023). These results suggest that the corpus callosum may be one of the key areas influenced by chronic smoking.

Delineation of Optic Radiation and Stria of Gennari on High-resolution Phase Difference Enhanced Imaging

RATIONALE AND OBJECTIVES Phase difference enhanced (PADRE) imaging technique can selectively enhanced the phase difference between the target and surrounding tissue. Our purpose is to assess the delineations of the optic radiation and primary visual cortex (stria of Gennari) using PADRE. MATERIALS AND METHODS The subjects were 6 healthy volunteers. Axial and coronal high-spatial resolution PADRE images were acquired covering the entire optic radiation using a 3T magnetic resonance system. Two radiologists evaluated the PADRE and susceptibility-weighted imaging (SWI)-like images for the delineation of four layers at the optic radiation (tapetum, internal sagittal stratum, external sagittal stratum, and adjacent white matter) on the basis of the anatomic appearances of the cadaveric specimens stained with Bodians method and Kluver-Barrera method. The radiologists also assessed the delineations of the stria of Gennari on PADRE and SWI-like images. RESULTS In all 6 healthy subjects, the PADRE images clearly identified the four layers at the optic radiation, as well as the stria of Gennari, which were difficult to appreciate in SWI-like images. The anatomic appearances of the optic radiation on PADRE images were more similar to those seen in the specimens stained with Kluver-Barrera method than with Bodians method. CONCLUSION The PADRE technique can delineate the four layers at the optic radiation and the stria of Gennari; the differences in myelin densities can also be enhanced. The PADRE technique may have the potential to reinforce the clinical utility of MRI in the diagnosis of diseases that affect the optic radiation and primary visual cortex.

Relationship between white matter integrity and serum cortisol levels in drug-naive patients with major depressive disorder: diffusion tensor imaging study using tract-based spatial statistics.

BACKGROUND Higher daytime cortisol levels because of a hyperactive hypothalamic-pituitary-adrenal axis have been reported in patients with major depressive disorder (MDD). The elevated glucocorticoids inhibit the proliferation of the oligodendrocytes that are responsible for myelinating the axons of white matter fibre tracts. AIMS To evaluate the relationship between white matter integrity and serum cortisol levels during a first depressive episode in drug-naive patients with MDD (MDD group) using a tract-based spatial statistics (TBSS) method. METHOD The MDD group (n = 29) and a healthy control group (n = 47) underwent diffusion tensor imaging (DTI) scans and an analysis was conducted using TBSS. Morning blood samples were obtained from both groups for cortisol measurement. RESULTS Compared with the controls, the MDD group had significantly reduced fractional anisotropy values (P<0.05, family-wise error (FWE)-corrected) in the inferior fronto-occipital fasciculus, uncinate fasciculus and anterior thalamic radiation. The fractional anisotropy values of the inferior fronto-occipital fasciculus, uncinate fasciculus and anterior thalamic radiation had significantly negative correlations with the serum cortisol levels in the MDD group (P<0.05, FWE-corrected). CONCLUSIONS Our findings indicate that the elevated cortisol levels in the MDD group may injure the white matter integrity in the frontal-subcortical and frontal-limbic circuits.

COMT Val158Met, but not BDNF Val66Met, is associated with white matter abnormalities of the temporal lobe in patients with first-episode, treatment-naïve major depressive disorder: a diffusion tensor imaging study

We investigated the association between the Val158Met polymorphism of the catechol-O-methyltransferase (COMT) gene, the Val66Met polymorphism of the brain-derived neurotrophic factor (BDNF) gene, and white matter changes in patients with major depressive disorder (MDD) and healthy subjects using diffusion tensor imaging (DTI). We studied 30 patients with MDD (17 males and 13 females, with mean age ± standard deviation [SD] =44±12 years) and 30 sex- and age-matched healthy controls (17 males and 13 females, aged 44±13 years). Using DTI analysis with a tract-based spatial statistics (TBSS) approach, we investigated the differences in fractional anisotropy, radial diffusivity, and axial diffusivity distribution among the three groups (patients with the COMT gene Val158Met, those with the BDNF gene Val66Met, and the healthy subjects). In a voxel-wise-based group comparison, we found significant decreases in fractional anisotropy and axial diffusivity within the temporal lobe white matter in the Met-carriers with MDD compared with the controls (P<0.05). No correlations in fractional anisotropy, axial diffusivity, or radial diffusivity were observed between the MDD patients and the controls, either among those with the BDNF Val/Val genotype or among the BDNF Met-carriers. These results suggest an association between the COMT gene Val158Met and the white matter abnormalities found in the temporal lobe of patients with MDD.

RELATIONSHIP BETWEEN THE CORTICAL THICKNESS AND SERUM CORTISOL LEVELS IN DRUG-NAÏVE, FIRST-EPISODE PATIENTS WITH MAJOR DEPRESSIVE DISORDER: A SURFACE-BASED MORPHOMETRIC STUDY.

In major depressive disorder (MDD) patients, higher morning cortisol levels due to a hyperactive hypothalamic–pituitary–adrenal (HPA) axis have been reported. The aim of the present study was to evaluate the relationship between cortical thinning and the serum cortisol levels during the first depressive episode in drug‐naïve MDD patients using an automated surface‐based morphometry (SBM) method.

Relationship between the catechol-O-methyl transferase Val108/158Met genotype and brain volume in treatment-naive major depressive disorder: Voxel-based morphometry analysis

Catechol-O-methyltransferase (COMT) is a methylation enzyme engaged in the degradation of dopamine and noradrenaline by catalyzing the transfer of a methyl group from S-adenosylmethionine. An association was found between the Valine (Val) 108/158Methionine (Met) COMT polymorphism (rs4680) and major depressive disorder (MDD). The authors prospectively investigated the relationship between the Val108/158Met COMT genotype and voxel-based morphometry (VBM) findings for patients with first-episode and treatment-naïve MDD and healthy subjects (HS). Participants comprised 30 MDD patients and 48 age- and sex-matched HS who were divided according to the COMT genotype. Effects of diagnosis, COMT genotype, and the genotype-diagnosis interaction in relation to brain morphology in the Val/Met and Val/Val individuals were evaluated using a VBM analysis of high-resolution magnetic resonance imaging findings. Among the Val/Met individuals, the volume of the bilateral caudate was significantly smaller for MDD patients than for HS. In the Val/Val individuals, the caudate volume was comparable between MDD patients and HS. Significant genotype-diagnosis interaction effects on brain morphology were noted in the right caudate.

Prediction of hard meningiomas: quantitative evaluation based on the magnetic resonance signal intensity.

Background From a surgical perspective, presurgical prediction of meningioma consistency is beneficial. Purpose To quantitatively analyze the correlation between the magnetic resonance (MR) signal intensity (SI) or apparent diffusion coefficient (ADC) and meningioma consistency and to determine which MR sequence could help predicting hard meningiomas. Material and Methods This study included 43 patients with meningiomas who underwent preoperative MR imaging (MRI), including T1-weighted (T1W) imaging, T2-weighted (T2W) imaging, fluid-attenuated inversion recovery (FLAIR), diffusion-weighted imaging (DWI), contrast-enhanced (CE)-T1W imaging, and CE-fast imaging employing steady-state acquisition (FIESTA). A neurosurgeon evaluated the tumor consistency using a visual analog scale (VAS) with the anchors “soft” (score = 0) and “hard” (score = 10). The SI ratio (tumor to cerebral cortex SI) and ADC value were compared with the tumor consistency. The sensitivity, specificity, and accuracy for predicting hard meningiomas (VAS score ≥8; 9 of 43 patients) were calculated using cutoff values for the SI ratio that were obtained in a receiver operating characteristic curve analysis. Results A significant negative correlation was observed between the tumor consistency and the SI ratio on T2W imaging, FLAIR, and CE-FIESTA (P < 0.05) but not on T1W imaging, CE-T1W imaging, and the ADC value. The sensitivity, specificity, and accuracy for predicting hard meningiomas were 89%, 79%, and 81% with T2W imaging; 89%, 76%, and 79% with FLAIR; and 100%, 74%, and 79% with CE-FIESTA, respectively. Conclusion Our results suggest that a quantitative assessment using conventional T2W imaging or FLAIR may be a simple and useful method for predicting hard meningiomas.

Relationship between a BDNF gene polymorphism and the brain volume in treatment-naive patients with major depressive disorder: A VBM analysis of brain MRI

The brain-derived neurotrophic factor (BDNF) relates to basic neuronal functions, such as cell survival, axonal outgrowth, and dendritic growth. The Val66Met polymorphism of the BDNF gene may affect genetic susceptibility to major depressive disorder (MDD). We prospectively investigated the relationship between the Val66Met BDNF genotype and voxel-based morphometry (VBM) findings for first episode and drug-naïve MDD patients and healthy subjects (HS). Participants comprised 38 MDD patients and 42 age- and sex-matched HS were divided into groups based on their BDNF genotype. The effects of diagnosis and genotype, as well as the genotype-diagnosis interaction, in relation to brain morphology were evaluated using a voxel-by-voxel statistical analysis of high-resolution magnetic resonance imaging (MRI) findings. Among the Met-carriers, the volume of the left middle frontal gyrus (composition of the prefrontal cortex [PFC]) was significantly smaller for MDD patients than for the HS, i.e., there was a significant genotype-diagnosis interaction effect on brain morphology noted in the left PFC. The BDNF polymorphism was associated with atrophy of the PFC in MDD patients, which suggests that the BDNF Val66Met polymorphism may play an important role in the pathogenesis of early stages of MDD.