Yukunori Korogi

Visceral fat area and markers of insulin resistance in relation to colorectal neoplasia

OBJECTIVE Although abdominal obesity and related metabolic abnormalities are hypothesized to promote colorectal carcinogenesis, direct confirmation of this effect is required. Here, we examined the relation of early-stage colorectal neoplasia to visceral fat area and markers of insulin resistance. RESEARCH DESIGN AND METHODS Subjects were participants in a comprehensive health screening conducted at the Hitachi Health Care Center, Ibaraki, Japan. During a 3-year period (2004–2007), a total of 108 patients with early-stage colorectal neoplasia, including 22 with early cancer, were identified among individuals who received both colorectal cancer screening and abdominal computed tomography scanning. Three control subjects matched to each case subject were randomly selected from those whose screening results were negative. Conditional logistic regression analysis was used to examine the association of measures of obesity and markers of insulin resistance with colorectal neoplasia, with adjustment for smoking and alcohol drinking. RESULTS Visceral fat area, but not subcutaneous fat area, was significantly positively associated with colorectal cancer, with odds ratios (95% CI) for the lowest to highest tertile of visceral fat area of 1 (reference), 2.17 (0.45–10.46), and 5.92 (1.22–28.65), respectively (Ptrend = 0.02). Markers of insulin resistance, particularly fasting glucose, were also positively associated with colorectal cancer risk. In contrast, no associations were observed for colorectal adenomas. CONCLUSIONS These results suggest that visceral adipose tissue accumulation and insulin resistance may promote the development of early-stage cancer but not adenoma in the colorectum.

Perfusion-sensitive MRI of cerebral lymphomas: a preliminary report.

PURPOSE To date, there have been no systematic reports examining cerebral lymphomas with perfusion-sensitive MRI. We sought to determine the characteristics of perfusion-sensitive MRI of these tumors. METHOD Five primary and three secondary cerebral lymphomas were analyzed. None of the patients had a history of AIDS. Various areas of relative cerebral blood volume (rCBV) within tumor were analyzed, and maximum CBV ratios (CBV[tumor/contralateral]) were identified for evaluation. RESULTS In three primary and three secondary cerebral lymphomas, maximum CBV ratios were <2.5 (mean 1.50). In others, maximum CBV ratios were markedly higher than those of the white matter (5.38 and 5.42). Mean maximum rCBV ratios of primary and secondary cerebral lymphomas were 2.93 and 1.43, respectively. There was no significant difference between the two groups. CONCLUSION Cerebral lymphomas had a tendency to have low rCBV values. This information may be helpful in diagnosing these tumors.

Value of dynamic susceptibility contrast magnetic resonance imaging in the evaluation of intracranial tumors.

The degree of tumor malignancy generally correlates to tumor grade, and the direct measurement of tumor vasculature is desired. Dynamic susceptibility contrast magnetic resonance imaging can provide relative cerebral blood volume and, therefore, is one of the most reliable methods to evaluate tumor vasculature in vivo. Tumor vessel size is extremely variable due to complex tumor angiogenesis, and the gradient-echo echo-planar imaging (GE-EPI) technique, which is sensitive to the total vascular bed, is well suited for this purpose. As many studies have shown, dynamic susceptibility contrast magnetic resonance imaging is more useful for grading glioma than conventional magnetic resonance imaging. We found that this technique can also provide supplementary information to differentiate between malignant lymphoma and glioma because the absence of tumor neovascularization of malignant lymphoma leads to low rCBV, which is in contrast to those of malignant gliomas. Indeed, this technique can be used for the differentiation of extra-axial tumors such as between meningioma and neurinoma. Recently, this technique has been focused toward determining the stereotactic biopsy site, monitoring the embolization of effect in meningioma, or evaluation of treatment effects after radiation therapy. However, the value of tumor rCBV is affected by many conditions such as the T1 relaxivity effects of gadolinium in the extravascular space. To establish the usefulness of this technique, further examination will be needed.

Gray and white matter volumetric and diffusion tensor imaging (DTI) analyses in the early stage of first-episode schizophrenia.

PURPOSE To determine whether statistical analyses of quantitative MR imaging data, including morphological changes, mean diffusivity (MD), and fractional anisotropy (FA), could provide useful biomarkers in early stage of first-episode schizophrenia. MATERIALS AND METHODS Twenty-three patients, who met all the criteria in the DSM-IV-TR category for schizophrenia excluding the duration of the disease (less than 6 months of follow-up), were examined by MR imaging during the initial consultation. Nineteen of the 23 patients were finally diagnosed to have schizophrenia after a 6-month follow-up, and they were included in this study as having been in the early stage of first-episode schizophrenia. Nineteen healthy volunteers also underwent MR imaging as age-matched controls. Three-dimensional spoiled gradient recalled acquisition with steady state (3D-SPGR) and diffusion tensor imaging (DTI) were performed at 3T. Image processing for voxel-based morphometry, a fully automatic technique for a computational analysis of differences in regional brain volume throughout the entire brain, was conducted using the Statistical Parametric Mapping 5 software package (SPM5). The 3D-SPGR images in the native space were bias-corrected; spatially normalized; segmented into gray matter, white matter, and cerebrospinal fluid images; and intensity-modulated using SPM5. A voxel-based analysis was conducted using both the MD and FA maps computed from DTI. The customized MD and FA template specific to this study was created from all participants. Thereafter, all the MD and FA maps in the native space were transformed onto the stereotactic space by registering each of the images to the customized MD and FA template. The two groups were compared using SPM5. Age and sex were treated as confounding covariates. RESULTS The patients demonstrated a significant increase in the MD of the left parahippocampal gyrus, left insula, and right anterior cingulate gyrus in comparison to the control subjects (FDR corrected p<0.05). No significant difference was observed in the correlation between the gray/white matter volume and FA. CONCLUSION These findings suggest that structural abnormalities in the brain are present during the early stage of first-episode schizophrenia and MD might therefore be a sensitive marker for the detection of these abnormalities.

The efficacy of a voxel-based morphometry on the analysis of imaging in schizophrenia, temporal lobe epilepsy, and Alzheimer's disease/mild cognitive impairment: a review

Voxel-based morphometry (VBM) done by means of MRI have provided new insights into the neuroanatomical basis for subjects with several conditions. Recently, VBM has been applied to investigate not only regional volumetric changes but also voxel-wise maps of fractional anisotropy (FA) computed from diffusion tensor imaging (DTI). The aim of this article is to review the recent work using VBM technique in particular focusing on schizophrenia, temporal lobe epilepsy (TLE), and Alzheimers disease (AD)/mild cognitive impairment (MCI). In patients with schizophrenia, VBM approach detects the structural brain abnormalities that appear normal on conventional MRI. Moreover, this technique also has the potential to emerge as a useful clinical tool for early detection and monitoring of disease progression and treatment response in patients with schizophrenia or AD/MCI. In TLE, VBM approach may help elucidate some unresolved important research questions such as how recurrent temporal lobe seizures affect hippocampal and extrahippocampal morphology. Thus, in the future, large cohort studies to monitor whole brain changes on a VBM basis will lead to a further understanding of the neuropathology of several conditions.

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.

Frequency and significance of pulmonary nodules on thin-section CT in patients with extrapulmonary malignant neoplasms

PURPOSE To determine the frequency and significance of pulmonary nodules detected on thin-section CT in patients with extrapulmonary malignant neoplasms. MATERIALS AND METHODS The institutional review board approved this study. This study retrospectively evaluated 308 patients with extrapulmonary carcinomas or sarcomas and had undergone thin-section chest CT (2mm slice thickness) for staging. Three radiologists identified non-calcified nodules and evaluated the size, the growth and the distance from the nearest pleural surface. The characteristics of the nodules were defined based on the results of either a diagnostic biopsy or nodule growth. RESULTS One or more non-calcified pulmonary nodules were detected in 75% of the patients (233/308). One hundred and thirty-seven of these patients had nodules that met the criteria of either benign or malignant nodules. Nodules smaller than 10mm were more likely to be benign, whereas those 10mm or greater were more likely to be malignant (22/26, 85%; P<.0001). Most nodules less than 10mm from the pleura were benign (91%), whereas approximately half of the nodules 10mm or more away from the pleura were malignant (20/43, 47%; P<.0001). Patients with melanoma, sarcoma, or testicular carcinoma were more likely to have malignant nodules. A multivariable analysis demonstrated the nodule size (P<.0001) and distance from the pleura were predictive of malignancy. CONCLUSION The nodule detection rate on thin-section CT in patients with extrapulmonary malignancy is high. Most of the nodules smaller than 10mm or less than 10mm from the pleura are benign.

Computer-aided detection of multiple sclerosis lesions in brain magnetic resonance images: False positive reduction scheme consisted of rule-based, level set method, and support vector machine

The purpose of this study was to develop a computerized method for detection of multiple sclerosis (MS) lesions in brain magnetic resonance (MR) images. We have proposed a new false positive reduction scheme, which consisted of a rule-based method, a level set method, and a support vector machine. We applied the proposed method to 49 slices selected from 6 studies of three MS cases including 168 MS lesions. As a result, the sensitivity for detection of MS lesions was 81.5% with 2.9 false positives per slice based on a leave-one-candidate-out test, and the similarity index between MS regions determined by the proposed method and neuroradiologists was 0.768 on average. These results indicate the proposed method would be useful for assisting neuroradiologists in assessing the MS in clinical practice.

Adenocarcinomas with predominant ground-glass opacity: correlation of morphology and molecular biomarkers.

PURPOSE To retrospectively identify successive changes in peripheral lung adenocarcinoma that feature dominant ground-glass opacity (GGO) at computed tomography (CT) and correlate with biomolecular markers. MATERIALS AND METHODS The institutional review board approved this retrospective study, and all 25 patients provided informed consent. Patients with lung adenocarcinomas smaller than 3 cm in diameter in whom tumor growth could be evaluated with CT before surgery were included. Two thoracic radiologists evaluated tumor growth by analyzing GGO type (pure or mixed) and size increases. Immunohistochemistry of the p53 protein and molecular analysis of the epidermal growth factor receptor (EGFR) and K-ras genes were performed. The Fisher exact test was used to assess statistical significance. RESULTS Tumor size increased in 19 of 25 patients (76%) during the observation period. The CT changes in 19 patients were classified into four patterns: persistent pure GGO (n = 8), change from pure to mixed GGO (n = 3), mixed GGO with growth of solid component (n = 4), and mixed GGO with growth of GGO component (n = 4). The remaining six patients (24%) had pure GGO without any interval changes. Staining for p53 was negative in all 14 patients with pure GGO and positive in six of 11 patients (55%) with mixed GGO (P < .01). In these six patients appearance or growth of the solid component was seen. EGFR mutations were found in both pure (36%) and mixed (45%) GGO lesions (P = .70). CONCLUSION Lung adenocarcinomas with a dominant GGO often possess EGFR mutations. Interval changes in the solid component may be related to p53 inactivation.