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Differences in corticocerebral structure and function between males and females and their effects on behavior and the prevalence of various neuropsychiatric disorders have been considered as a fundamental topic in various fields of neuroscience. Recent studies on working memory (WM) reported the impact of sex on brain connectivity patterns, which reflect the important role of functional connectivity in the sex topic. Working memory, one of the most important cognitive tasks performed by regions of the PFC, can provide evidence regarding the presence of a difference between males and females. The present study aimed to assess sex differences in brain functional connectivity during working memory-related tasks by using functional near-infrared spectroscopy (fNIRS). In this regard, nine males and nine females completed a dual n-back working memory task with two target inputs of color and location stimuli in three difficulty levels (n = 0, 1, 2). Functional connectivity matrices were extracted for each subject for each memory load level. Females made less errors than males while spending more time performing the task for all workload levels except in 0-back related to the color stimulus, where the reaction time of females was shorter than males. The results of functional connectivity reveal the inverse behavior of two hemispheres at different memory workload levels between males and females. In the left hemisphere, males exhibited stronger connectivity compared to the females, while stronger connectivity was observed in the females' right hemisphere. Furthermore, an inverse trend was detected in the channel pairs with significant connectivity in the right hemisphere of males (falling) and females (rising) by enhancing working memory load level. Considering both behavioral and functional results for two sexes demonstrated a better performance in females due to the more effective use of the brain. The results indicate that sex affects functional connectivity between different areas in both hemispheres of the brain during cognitive tasks of varying difficulty levels although the general impression is that spatial capabilities are considered as a performance of the brain's right hemisphere. These results reinforce the presence of a sex effect in the functional imaging studies of hemodynamic function and emphasize the importance of evaluating brain network connectivity for achieving a better scientific understanding of sex differences.

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BACKGROUND: The objective of the study is to evaluate elastography ultrasound findings in patients with scleroderma (SS) and to clarify the effectiveness of elastosonography to differentiate scleroderma lesions from any skin lesion considering tissue elasticity. METHODS: Thirty-six SS patients definite diagnosis of systemic sclerosis according to American College of Rheumatology criteria and 36 healthy subjects were enrolled. Volar aspect of the middle forearm and arm in addition to the dorsal aspect of the fingers were evaluated by sonoelastography. The RGB (red, green, blue) image is a three-dimensional matrix. A color image RGB is an M × N × 3 array of color pixels. The total pixels, total blue pixels, and blue index compared between SS cases and controls. RESULTS: Mean age of patients was 41.3 ± 10.3 years and mean age of controls was 39.8 ± 9.3 years. Mean-modified Rodnan skin score of the whole body was 11.9 and mean duration of disease was 6.2 years. Mean total blue pixels in the arm were significantly different between cases and controls. Mean total image pixels, total blue pixels, and blue index in the forearm were significantly different between cases and controls. Elastography findings in the finger were not significantly different between cases and controls. CONCLUSIONS: Sonoelastography could be used for evaluating skin of forearm in sclerodermic cases which will be helpful for disease evaluation in clinical course.

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BACKGROUND: The study of the brain network based on the basis of the resting-state functional Magnetic Resonance Imaging (fMRI) provided some promising results to investigate changes in connectivity among different brain regions because of Alzheimer's disease (AD). OBJECTIVE: In addition, the graph theory has been utilized as an efficient tool in diagnosing Alzheimer and in finding the developed differences in the brain as the result of this disease. METHODS: This study considers 16 areas of the brain, which play a major role in the development of AD. Accordingly, the time series and the correlation matrix were yielded for each of these areas. Then, by using threshold we obtained functional connectivity from correlation matrices along with the brain graph parameter for Normal Controls and AD groups were obtained in order to compare the existing differences. RESULTS: The differences of characteristics among healthy individuals and patients suffering from Alzheimer has been investigated in this study through the formation of brain graphs for 16 areas and the utilization of data on Normal Controls (13 persons) and patients suffering from Alzheimer (13 patients). CONCLUSIONS: Some of the properties of the graph are the characteristic path length, the clustering coefficient, the local and global efficiency yield of ability to separate the two groups which may be used to diagnose Alzheimer.

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OBJECTIVES: To demonstrate magnetic resonance enterography (MRE) features of mesenteric lymph nodes (LN) in patients with Crohn's disease (CD) and investigate whether they follow enhancement or apparent diffusion coefficient (ADC) parameters of bowel. METHODS: This study was approved by the institutional review board. A total of 788 MREs from patients with CD were retrospectively reviewed. Eighty-eight patients, aged 16-66 years, including 59 active cases, were enrolled based on inclusion criteria. In each MRE, two segments (normal and abnormal) and two LNs (regional and non-regional) were independently suggested, consensually chosen, and analyzed by two radiologists. Signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were calculated to assess signal intensities (SI) at 30, 60 and 180 s after contrast administration, as well as slope of enhancement (SOE). Enhancement parameters and ADC values were compared. RESULTS: Regional LNs showed significantly higher SI30, SI60 and SI180 (CNR&SNR) and lower ADC values in active vs. inactive groups (all p<0.05) without significant difference in number or size. Strong correlations were demonstrated between abnormal segments and regional LNs in active group in terms of SI30, SI60, SI180, SOE0-30 and ADC values (r = 0.679 to 0.774, all p<0.001). SI180, SOE60-180 and ADC values were moderately correlated between abnormal segments and regional LNs in inactive group (r = 0.448 to 0.595, all p<0.05). In logistic regression analyses, SOE0-30 and ADC value of regional LNs independently predicted active CD. CONCLUSION: Mesenteric LNs follow quantitative enhancement and diffusion parameters of bowel in active CD. SOE0-30 and ADC value of LN could predict disease activity. KEY POINTS: • Mesenteric LNs may strongly follow enhancement pattern of bowel in active CD. • DWI parameters of LNs and bowel were strongly correlated in active CD. • SI180 was moderately correlated between bowel and LNs in inactive CD. • DWI parameters were moderately correlated between LNs and bowel in inactive CD. • SOE0-30 and ADC value of mesenteric LN could predict disease activity.

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BACKGROUND/AIM: Existing evidence points to an altered status of iron metabolism in obesity. We aimed to investigate whether central obesity is independently associated with estimated liver iron content (liver T2* value) in general population that used the noninvasive assessment method by MRI. METHODS: The study was carried out on 200 subjects randomly selected from the Golestan Cohort Study who underwent abdominal MRI. Quantitative T2* maps of entire cross-sectional area of liver were calculated using a semi-automated software for estimating the levels of iron content. Segmentation and calculation of visceral (VFA) and subcutaneous fat area (SFA) were also performed. RESULTS: There was no significant difference in mean liver T2* values between obese (body mass index, BMI >30 kg/m2) and non-obese (BMI ≤30 kg/m2) subjects. After controlling for other covariates, no statistically significant association was detected between liver T2* values and VFA, SFA and VFA/SFA ratio. The drop in the relative signal intensity as an indicator of steatosis and serum ferritin predicted liver T2* values that almost had the same strength (standardized ß of -0.41 and -0.41, respectively). CONCLUSIONS: Central obesity indices are not correlated with estimated liver iron content by MRI. Hepatic steatosis and serum ferritin seem to be the best predictors of hepatic T2* value. Since central obesity indices were not direct predictors of hepatic T2* value after the adjustment for confounding factors, it is possible that lipid accumulation in the liver locally, but not systematically, influences hepatic iron metabolism.

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BACKGROUND: To investigate the association between non-alcoholic fatty liver disease (NAFLD) and quantitative measures of central adiposity in the general population using a semi-automated method on magnetic resonance imaging (MRI) data. METHODS: Subjects were recruited from Golestan Cohort Study. Two groups of 120 individuals with and without fatty liver were randomly selected based on findings of ultrasound. Non-invasive diagnosis of NAFLD was made by combination of ultrasound and MRI. Various anthropometric indices including body mass index (BMI), waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR) were measured. Segmentation and calculation of visceral (VFA) and subcutaneous fat area (SFA) were performed on three levels of MRI slices using semi-automated software. RESULTS: A total of 109 individuals fulfilled the NAFLD criteria, while 92 subjects were selected as the control group. All obesity measures, except for SFA, were significantly higher in subjects with NAFLD compared to controls. Significant associations were found between NAFLD and adiposity indices, except for SFA, with the highest odds ratio observed in WHR (OR: 3.37, CI: 1.40-3.70, P < 0.001). VFA also had the greatest correlation with ultrasound (r = 0.523, P < 0.001) and MRI (r = 0.546, P < 0.001) indicators of NAFLD. CONCLUSIONS: Quantitative measures of visceral adiposity are associated with NAFLD, while subcutaneous fat measures are poor indicators for identifying NAFLD. Compared to conventional anthropometric indices, VFA best correlates with ultrasound and MRI criteria of fatty liver.

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OBJECTIVE: To evaluate grey-scale and elastography ultrasound imaging findings in patients with CTS compared to nerve conductive studies. METHOD: Sixty median nerves of 31 cases with confirmed CTS and 44 median nerves in 22 controls (healthy volunteers) who had no clinical evidence of CTS were evaluated. An expert radiologist performed all US evaluations. The RGB image is a three-dimensional matrix. A colour image RGB is an M × N × 3 array of colour pixels. The total pixels, total blue and red pixels, and blue and red indexes were compared between cases and controls. RESULTS: Of the 60 nerves in the cases, 17 (16.3%) were mildly affected, 30 (28.8%) were moderately affected, and 13 (12.5%) were severely affected. Mean CSA, total blue pixels and blue indexes were significantly different between controls and cases with different levels of disease severity. The best cut-off point in the blue index to differentiate patients from controls was 0.1486, with a sensitivity and specificity of 80 and 70% (AUC = 0.79, P < 0.001), respectively. The best cut-off point for the red index to differentiate patients from controls was 0.1896, with a sensitivity and specificity of 70 and 55% (AUC = 0.64, P = 0.01), respectively. CONCLUSION: Sono-elastography could be a useful diagnostic method for evaluating CTS severity in affected cases.

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RATIONALE AND OBJECTIVES: Existing evidence suggests potential contribution of iron in pathogenesis of nonalcoholic fatty liver disease (NAFLD). We aimed to investigate whether hepatic iron content correlates with liver enzyme levels in NAFLD using a noninvasive magnetic resonance imaging (MRI) technique. MATERIALS AND METHODS: Subjects from Golestan Cohort Study were randomly selected. Diagnosis of NAFLD was made by combination of ultrasound and MRI. Subjects with NAFLD were divided into two groups with high (H-NAFLD) and low (L-NAFLD) enzyme level according to 95th percentile of alanine aminotransferase (ALT) value in normal population. Quantitative T2* maps of entire cross-sectional area of liver were calculated on pixel-by-pixel basis using a semiautomated software. RESULTS: A total of 207 subjects were enrolled. Mean T2* values were significantly lower in NAFLD group than controls (P < .001) indicating higher iron content. Male subjects with H-NAFLD had statistically lower T2* values than those with L-NAFLD in multivariate analysis (odds ratio, 0.74; 95% confidence interval [CI], 0.58-0.95), whereas this was not observed in women. Unlike women, there was significant negative correlation between ALT levels and T2* values in men with H-NAFLD (r = -0.66, P = .01). Every 1-millisecond decrement in T2* value was associated with 6.37 IU/L increase in ALT level (95% CI, 1.8-10.9, P = .01) in men with H-NAFLD. CONCLUSIONS: Higher hepatic iron in men with H-NAFLD, estimated by T2* mapping, may support the role of iron in possible progression of simple steatosis to nonalcoholic steatohepatitis. Lack of such correlation in women could be attributed to relatively lower iron storage or other mechanisms rather than iron.

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