Performance of deep learning synthetic CTs for MR-only brain radiation therapy

PURPOSE: To evaluate the dosimetric and image-guided radiation therapy (IGRT) performance of a novel generative adversarial network (GAN) generated synthetic CT (synCT) in the brain and compare its performance for clinical use including conventional brain radiotherapy, cranial stereotactic radiosurgery (SRS), planar, and volumetric IGRT. METHODS AND MATERIALS: SynCT images for 12 brain cancer patients (6 SRS, 6 conventional) were generated from T1-weighted postgadolinium magnetic resonance (MR) images by applying a GAN model with a residual network (ResNet) generator and a convolutional neural network (CNN) with 5 convolutional layers as the discriminator that classified input images as real or synthetic. Following rigid registration, clinical structures and treatment plans derived from simulation CT (simCT) images were transferred to synCTs. Dose was recalculated for 15 simCT/synCT plan pairs using fixed monitor units. Two-dimensional (2D) gamma analysis (2%/2 mm, 1%/1 mm) was performed to compare dose distributions at isocenter. Dose-volume histogram (DVH) metrics (D(95%) , D(99%) , D(0.2cc,) and D(0.035cc) ) were assessed for the targets and organ at risks (OARs). IGRT performance was evaluated via volumetric registration between cone beam CT (CBCT) to synCT/simCT and planar registration between KV images to synCT/simCT digital reconstructed radiographs (DRRs). RESULTS: Average gamma passing rates at 1%/1mm and 2%/2mm were 99.0 ± 1.5% and 99.9 ± 0.2%, respectively. Excellent agreement in DVH metrics was observed (mean difference ≤0.10 ± 0.04 Gy for targets, 0.13 ± 0.04 Gy for OARs). The population averaged mean difference in CBCT-synCT registrations were \u3c0.2 mm and 0.1 degree different from simCT-based registrations. The mean difference between kV-synCT DRR and kV-simCT DRR registrations was \u3c0.5 mm with no statistically significant differences observed (P \u3e 0.05). An outlier with a large resection cavity exhibited the worst-case scenario. CONCLUSION: Brain GAN synCTs demonstrated excellent performance for dosimetric and IGRT endpoints, offering potential use in high precision brain cancer therapy

Epidemiological trend of suicide in north of Iran from 2011 to 2018 with a focus on joinpoint regression

Background: Deaths due to potential suicide are preventable and this phenomenon is costly for the health care system and contradicts the values and cultural standards of an Islamic country. Methods: This study is a retrospective study. The research population includes all cases of suicide during the years 2011-2018 who were referred to the emergency department of Babol hospitals. The results were analyzed using SPSS v.23 and Joinpoint Trend Analysis software 4.9.0.0 to identify significant changes in the temporal trends of the outbreak. Results: The highest percentage of suicides occurred in summer (27.8), on Saturdays (13) and at night (53). A total of 1.9 of the cases were commit suicides (leading to death). The highest frequency of suicide was shown in 1397 (21.2) and the lowest in 1392 (5.1) and was more common in women (68.2 vs. 31.8). Suicide-related deaths was higher in the second four years (63.5), but suicide rate was significantly higher in the first four years (2011-2014) and the mortality rate due to suicide was higher in men than women. Conclusion: Suicide attempts were higher in women than men but the death rate was higher in men which means that men attempt suicide more seriously than women. The model also predicted that suicide rates would rise in the coming years. For this reason, this important issue, along with a detailed analysis of the roots of suicidal ideation and preventive measures, should be considered by health officials and social institutions. &#160

Are endoscopic findings predictive for the presence of H. pylori infection? What about indirect histologic findings?

<font face="TimesNewRoman,Bold" size="1"><p align="left"><strong>BACKGROUND: </strong><font face="TimesNewRoman" size="2">It is still controversial whether certain endoscopic features can be used to diagnose Helicobacter pylori related gastritis. Our aim was to determine how macroscopic findings were related to histomorphological changes and the presence of H. pylori in patients undergoing endoscopy.</font></p></font><font face="TimesNewRoman,Bold" size="1"><p align="left"><strong>METHODS: </strong><font face="TimesNewRoman" size="2">The study population involved 501 consecutive gastrointestinal (GI) clinic admissions who underwent esphagogastroduodenoscopy for upper GI symptoms between October 2002 and March 2004. At least 2 antral and 2 body biopsies were obtained from each patient and were examined histologically for the presence of gastritis and were stained for H. pylori using modified Giemsa staining method. Endoscopic findings were reviewed retrospectively by two experts blinded to the H. pylori status and patients history. The endoscopic findings of gastritis, classified by a modification of the Sydney system and histological findings were determined by updated Sydney system. Statistical analysis was done using SPSS 11.</font></p></font><font face="TimesNewRoman,Bold" size="1"><p align="left"><strong>RESULTS: </strong><font face="TimesNewRoman" size="2">A total of 501 consecutive patients (256 females, 245males) ranging from 8 to 91 years (mean, 49.5 years) were studied. H. pylori was found in 326 patients (65.1%). Relative frequency of H pylori in females was 53% and in males was 47%. Rugal hypertrophy, raised erosion and bleeding were observed only in patients with H. pylori infection (specificity = 100%). Neutrophil activity also was observed only in patients with H. pylori infection. Among endoscopic findings, erythema showed a high sensitivity (81.3%) and positive predictive value (87.1%) for the diagnosis of H. pylori infection. Gastritis was present in 84.3 % of all patients and 97% (316/326) of those with H. pylori and 56.6% (99/175) of those without H. pylori. There was significant statistical correlation between H. pylori infection and gastritis (P<0.001). H. pylori was present in 76% (316/415) of gastritis patients and 5.1% (4/77) of patients without gastritis.</font></p></font><font face="TimesNewRoman,Bold" size="1"><p align="left"><strong>CONCLUSIONS: </strong><font face="TimesNewRoman" size="2">An accurate endoscopic assessment of gastritis according to the Sydney system along with the histological findings is valuable indicator of H. pylori infection.</font></p></font><font face="TimesNewRoman,Bold" size="1"><p align="left"><strong>KEY WORDS: </strong><font face="TimesNewRoman" size="2">Helicobacter pylori, gastritis, Sydney system, peptic ulcer.</font></p></font&gt

Should We Look for Celiac Disease among all Patients with Liver Function Test Abnormalities?

Background: Celiac disease (CD) has been found in up to 10% of the patients presenting with unexplained abnormal liver function tests (LFT). As there is no precise data from our country in this regard, we investigated the prevalence of CD in patients presenting with abnormal LFT. Methods: From 2003 to 2008, we measured IgA anti-tissue transglutaminase (t-TG) antibody (with ELISA technique) within the first-level screening steps for all patients presenting with abnormal LFT to three outpatient gastroenterology clinics in Isfahan, IRAN. All subjects with an IgA anti-tTG antibody value of >10 μ/ml (seropositive) were undergone upper gastrointestinal endoscopy and duodenal biopsy. Histopathological changes were assessed according to the Marsh classification. CD was defined as being seropositive with Marsh I or above in histopathology and having a good response to gluten free diet (GFD). Results: During the study, 224 patients were evaluated, out of which, 10 patients (4.4%) were seropositive for CD. Duodenal biopsies were performed in eight patients and revealed six (2.7%) cases of Marsh I or above (four Marsh IIIA, two Marsh I), all of them had good response to GFD. The overall prevalence of CD among patients with hypertransaminasemia, autoimmune hepatitis, and cryptogenic cirrhosis was determined as 10.7% (3/28), 3.4% (2/59), and 5.3% (1/19), respectively. Conclusion: Serological screening with IgA anti-tTG antibody test should be routinely performed in patients presenting with abnormal LFT and especially those with chronic liver diseases including hypertransaminasemia, autoimmune hepatitis, and cryptogenic cirrhosis

Generating synthetic CTs from magnetic resonance images using generative adversarial networks

PURPOSE: While MR-only treatment planning using synthetic CTs (synCTs) offers potential for streamlining clinical workflow, a need exists for an efficient and automated synCT generation in the brain to facilitate near real-time MR-only planning. This work describes a novel method for generating brain synCTs based on generative adversarial networks (GANs), a deep learning model that trains two competing networks simultaneously, and compares it to a deep convolutional neural network (CNN). METHODS: Post-Gadolinium T1-Weighted and CT-SIM images from fifteen brain cancer patients were retrospectively analyzed. The GAN model was developed to generate synCTs using T1-weighted MRI images as the input using a residual network (ResNet) as the generator. The discriminator is a CNN with five convolutional layers that classified the input image as real or synthetic. Fivefold cross-validation was performed to validate our model. GAN performance was compared to CNN based on mean absolute error (MAE), structural similarity index (SSIM), and peak signal-to-noise ratio (PSNR) metrics between the synCT and CT images. RESULTS: GAN training took ~11 h with a new case testing time of 5.7 ± 0.6 s. For GAN, MAEs between synCT and CT-SIM were 89.3 ± 10.3 Hounsfield units (HU) and 41.9 ± 8.6 HU across the entire FOV and tissues, respectively. However, MAE in the bone and air was, on average, ~240-255 HU. By comparison, the CNN model had an average full FOV MAE of 102.4 ± 11.1 HU. For GAN, the mean PSNR was 26.6 ± 1.2 and SSIM was 0.83 ± 0.03. GAN synCTs preserved details better than CNN, and regions of abnormal anatomy were well represented on GAN synCTs. CONCLUSIONS: We developed and validated a GAN model using a single T1-weighted MR image as the input that generates robust, high quality synCTs in seconds. Our method offers strong potential for supporting near real-time MR-only treatment planning in the brain

An Electroconductive, Thermosensitive, and Injectable Chitosan/Pluronic/Gold-Decorated Cellulose Nanofiber Hydrogel as an Efficient Carrier for Regeneration of Cardiac Tissue

Myocardial infarction is a major cause of death worldwide and remains a social and healthcare burden. Injectable hydrogels with the ability to locally deliver drugs or cells to the damaged area can revolutionize the treatment of heart diseases. Herein, we formulate a thermo-responsive and injectable hydrogel based on conjugated chitosan/poloxamers for cardiac repair. To tailor the mechanical properties and electrical signal transmission, gold nanoparticles (AuNPs) with an average diameter of 50 nm were physically bonded to oxidized bacterial nanocellulose fibers (OBC) and added to the thermosensitive hydrogel at the ratio of 1% w/v. The prepared hydrogels have a porous structure with open pore channels in the range of 50–200 µm. Shear rate sweep measurements demonstrate a reversible phase transition from sol to gel with increasing temperature and a gelation time of 5 min. The hydrogels show a shear-thinning behavior with a shear modulus ranging from 1 to 12 kPa dependent on gold concentration. Electrical conductivity studies reveal that the conductance of the polymer matrix is 6 × 10−2 S/m at 75 mM Au. In vitro cytocompatibility assays by H9C2 cells show high biocompatibility (cell viability of >90% after 72 h incubation) with good cell adhesion. In conclusion, the developed nanocomposite hydrogel has great potential for use as an injectable biomaterial for cardiac tissue regeneration