Magnetic field strength increase yields significantly greater contrast-to-noise ratio increase: Measured using BOLD contrast in the primary visual area

RATIONALE AND OBJECTIVE: The advantage of a higher static magnetic field for functional MRI has been advocated; however, the observed advantage varies. The aim of this study was to evaluate the effect of increasing static magnetic field strength on the task-related increase in blood oxygenation level-dependent (BOLD) signal and residual noise with visual stimuli of different frequencies, which may enable better comparisons of results of different MRI scanners. MATERIALS AND METHODS: Eight right-handed healthy volunteers were presented checkerboard stimuli flickering at 5 different frequencies up to 8 Hz. Field strengths of 3 T or 1.5 T were used to measure frequency-dependent signal changes in the primary visual area. Regression analysis was performed for the signal increase and the "noise," which was defined by the root mean of squares of the residual signal fluctuation. These values were compared and their relationship was analyzed. Imaging parameters were identical except for the use of a 25% shorter echo time using 3 T. RESULTS: The frequency-dependent increase in BOLD signal using 3 T was twice that using 1.5 T. In contrast, the ratio of noise values that reflect time-course signal fluctuation (3 T/1.5 T) was only 0.88. There was large individual variance in these values, but the slope and noise values were linearly related using either field strength. The contrast-to-noise ratio using 3 T was 2.3 times higher than that using 1.5 T. CONCLUSION: There was a greater-than-linear increase in the contrast-to-noise ratio compared with the increase of field strength, demonstrating an advantage of using higher field strengths in fMRI studies.     

Predictive Value of the Time–Intensity Curves on Dynamic Contrast-Enhanced Magnetic Resonance Imaging for Lymphatic Spreading in Breast Cancer

Purpose Dynamic contrast-enhanced magnetic resonance imaging (CE-MRI) has emerged as a promising diagnostic modality in various breast cancer treatments. However, little is known about the correlation between the pattern of time to signal intensity curves (TIC) on the CE-MRI and clinicopathologic features. This study was designed to investigate these correlations and evaluate the predictive value of TIC on CE-MRI in order to identify high-risk patients.Methods Between 2001 and 2003, 101 lesions were evaluated to detect malignancy on CE-MRI in 101 women who were suspected of having breast tumors based on either clinical findings or conventional imaging studies. Moreover, the clinicopathologic findings were compared with the pattern of TIC for the 69 surgically treated malignant lesions.Results In detecting malignancy, the sensitivity, specificity, and accuracy were 78.7%, 88.5%, and 81.2%, respectively, in the 101 breast lesions. Especially for the 69 surgically treated malignant lesions, in comparison with breast cancer tumors with the benign pattern of TIC, the breast cancer tumors with a malignant pattern were found more frequently in lymphatic invasion (P < 0.01) and lymph node metastasis (P < 0.005), although no statistical correlation regarding the histological type, tumor size, vascular invasion, extensive intraductal component, hormone receptor status, or pathological stage was noted between the two groups. According to a logistic regression model, lymph node metastasis was found to be a significant independent variable.Conclusion The pattern of TIC could be used to predict lymphatic spreading associated with lymph node metastasis prior to surgery as well as to detect malignancy. Therefore, a more detailed evaluation should be made to identify the presence of lymphatic spreading in patients with a malignant pattern of TIC.This study was presented at the 103rd Annual Congress of the Japan Surgical Society, Sapporo, Hokkaido, June 4–6, 2003     

Vascular involvement in a patient with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes

A 26-year-old man with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) was admitted to our hospital for further cardiovascular examination. A muscle biopsy demonstrated strongly succinate dehydrogenase-reactive blood vessels. Pulse wave contour analysis revealed that both capacitive and oscillatory compliance were markedly reduced in this patient compared with 45 normal age-matched control subjects. Hepatocyte growth factor was remarkably elevated in this patient over that of 10 normal control subjects. These findings suggest that a MELAS patient has not only pathologic but also functional vascular involvement. If so, patients with MELAS need systemic vascular assessment.     

Cerebrospinal fluid and serum markers of inflammation in autism

Systemic immune abnormalities have no known relevance to brain dysfunction in autism. In order to find evidence for neuroinflammation, we compared levels of sensitive indicators of immune activation: quinolinic acid, neopterin, and biopterin, as well as multiple cytokines and cytokine receptors, in cerebrospinal fluid and serum from children with autism, to control subjects with other neurologic disorders. In cerebrospinal fluid from 12 children with autism, quinolinic acid (P = 0.037) and neopterin (P = 0.003) were decreased, and biopterin (P = 0.040) was elevated, compared with control subjects. In sera from 35 persons with autism, among cytokines, only tumor necrosis factor receptor II was elevated compared with controls (P < 0.02). Decreased quinolinic acid and neopterin in cerebrospinal fluid are paradoxical and suggest dysmaturation of metabolic pathways and absence of concurrent infection, respectively, in autism. Alternatively, they may be produced by microglia but remain localized and not expressed in cerebrospinal fluid.     

Surgery results using different uterine wall incision directions in laparoscopic myomectomy of the intramural myoma

Objective :  To study clinical outcomes for different uterine wall incision directions, comparing vertical incision and transverse incision in laparoscopic myomectomy of the intramural myoma.
Methods :  Laparoscopic myomectomies were performed on 50 women with intramural myomas. Using a table of random numbers, they were randomly divided into a vertical incision group (25 women) and a transverse incision group (25 women) according to the direction of incisions in the uterine wall. The numbers of enucleated myoma, operation duration, amount of bleeding, and numbers of sutures were compared. The Mann–Whitney U -test was used for analysis.
Results :  For the transverse incision group, the amount of bleeding (137.6 ± 88.1 mL) was a significantly lower value ( P  = 0.0426) than for the vertical incision group (235.8 ± 169.4 mL). In addition, in cases where the maximum myoma nucleus diameter was 7 cm or larger, operation duration (129.0 ± 32.5 min) and amount of bleeding (158.9 ± 87.1 mL) showed significantly lower values ( P  = 0.0067 and P =  0.0002, respectively) for the transverse incision group than did operation duration (362.3 ± 147.3 min) and amount of bleeding (362.3 ± 147.3 mL) for the vertical incision group.
Conclusion :  Transverse incision of the uterine wall is useful to reduce the amount of bleeding in the laparoscopic myomectomy of the intramural myoma. Transverse incision also shortens operation duration in cases where the myoma nuclei are large. (Reprod Med Biol 2004; 3 : 33–37)     

The application of a variable-pressure scanning electron microscope with energy dispersive X-ray microanalyser to the diagnosis of electrocution: a case report

We describe here a case of accidental electrocution. A 48-year-old male was found dead in his room. At autopsy, there was a current mark on the right thumb and big toe. Histological examination revealed that the skin wound had the characteristics of a current mark, including vacuolation and elongation of the cell nuclei. We could also identify titanium metallization on the skin surface of the current mark using a variable-pressure scanning electron microscope (VP-SEM) equipped with energy dispersive X-ray microanalyser (EDX). The autopsy finding and the subsequent investigation support the conclusion that the cause of his death was electrocution. Our result shows that the VP-SEM with EDX is a useful tool for the forensic diagnosis of electrocution.     

Immunohistochemical localization of eotaxin immunoreactivity in nasal polyps

Eotaxin is a C-C chemokine that acts to selectively induce local accumulation of eosinophils and basophils. Eotaxin is also believed to be involved in the infiltration of eosinophils in the nasal polyps of patients with chronic sinusitis. However, only a few studies on eotaxin in nasal polyps have been performed. In this study, we investigated the localization of eotaxin in human nasal polyps and the identification of eotaxin-positive cells using immunohistochemistry. The distribution of eotaxin immunoreactivity in the nasal polyps of patients with chronic sinusitis was found to almost coincide with the presence of eosinophils. Eotaxin immunoreactivity was also detected in some vascular endothelial cells. These findings suggest that eotaxin is produced by eosinophils and vascular endothelial cells in nasal polyps and is involved in the accumulation of eosinophils in nasal polyps.