Differentiation between Pancreatic Ductal Adenocarcinoma and Normal Pancreatic Tissue for Treatment Response Assessment using Multi-Scale Texture Analysis of CT Images.

Background: Pancreatic ductal adenocarcinoma (PDAC) is the most prevalent type of pancreas cancer with a high mortality rate and its staging is highly dependent on the extent of involvement between the tumor and surrounding vessels, facilitating treatment response assessment in PDAC. Objective: This study aims at detecting and visualizing the tumor region and the surrounding vessels in PDAC CT scan since, despite the tumors in other abdominal organs, clear detection of PDAC is highly difficult. Material and Methods: This retrospective study consists of three stages: 1) a patch-based algorithm for differentiation between tumor region and healthy tissue using multi-scale texture analysis along with L1-SVM (Support Vector Machine) classifier, 2) a voting-based approach, developed on a standard logistic function, to mitigate false detections, and 3) 3D visualization of the tumor and the surrounding vessels using ITK-SNAP software. Results: The results demonstrate that multi-scale texture analysis strikes a balance between recall and precision in tumor and healthy tissue differentiation with an overall accuracy of 0.78±0.12 and a sensitivity of 0.90±0.09 in PDAC. Conclusion: Multi-scale texture analysis using statistical and wavelet-based features along with L1-SVM can be employed to differentiate between healthy and pancreatic tissues. Besides, 3D visualization of the tumor region and surrounding vessels can facilitate the assessment of treatment response in PDAC. However, the 3D visualization software must be further developed for integrating with clinical applications.

A Multicenter Survey on the Trend of Chest CT Scan Utilization: Tracing the First Footsteps of COVID-19 in Iran.

BACKGROUND: Chest computed tomography (CT) scan has been used widely to diagnose COVID-19 in Iran. OBJECTIVES: To trace the footsteps of COVID-19 in Iran by exploring the trend in using chest CT scans and its economic impact on radiology departments. Methods: In this cross-sectional study, the number of imaging examinations from 33 tertiary radiology departments in 9 large cities of Iran was collected from September 23, 2019 to March 20, 2020 (Months 1 to 6) and the corresponding months in 2018-2019. RESULTS: A 50.2% increase was noted in the chest CT scan utilization in 2019-2020 compared to 2018-2019. This increase was +15%, +15%, +27%, +2%, +1% in Months 1-5 of 2019-2020, respectively. In Month 6 of 2019-2020, a 251% increase in the acquisition of chest CT scans was observed compared to the Month 6 of 2018-2019. Following negative balance of revenue from Month 1 to 5 with respect to the inflation rate, the total income in Month 6 was further 1.5% less than the same Month in 2018-19. CONCLUSION: The observed peak in chest CT utilization in Month 3 prior to the surge in Month 6 could be explained by the seasonal influenza. However, unawareness about an emerging viral disease, i.e. COVID-19, might have underutilized chest CT in Months 4 and 5 before the official announcement in Month 6. The unbalanced increase in the workload of radiology departments in the shortage of cardiothoracic radiologists with the simultaneous decrease in income initiated a vicious cycle that worsened the economic repercussions of the pandemic.

Central Obesity and Liver Iron Content: A Noninvasive Assessment in General Population by Magnetic Resonance Imaging.

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.

Assessment of Abdominal Fat Distribution in Non-Alcoholic Fatty Liver Disease by Magnetic Resonance Imaging: a Population-based Study.

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.

Liver enzyme levels and hepatic iron content in Fatty liver: a noninvasive assessment in general population by T2* mapping.

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.