Use of Magnetic Resonance Imaging to Assess the Regenerative Effects of Adipose Tissue-Derived Mesenchymal Stem Cells in a Rabbit Cartilaginous Laryngeal Defect Model.

Background: Stenosis and scar formation after repair of laryngeal tissue defects are serious problems that can significantly influence a patient's quality of life. Objective: In this study, we evaluated the use of magnetic resonance imaging to assess the efficacy of adipose tissue-derived mesenchymal stem cells (ASCs) on cartilaginous regeneration in an experimental rabbit model. Methods: Ten male white Dutch rabbits each had a 5 mm cartilaginous defect created surgically in the right and left thyroid lamina. On the right side, ASCs labeled with iron oxide particles were infused. As a control, the left side was left untreated. Repair of the defects were then evaluated by direct observation, histological evaluation, and magnetic resonance imaging monitoring done on days 1, 7, 14, and 28. Results: Histological examination revealed that compared with control, transplanted ASCs significantly increased cartilage regeneration (P ˂ 0.001), reduced inflammation (P ˂ 0.001), and fibrosis (P = 0.050). Magnetic resonance imaging tracking showed accurate placement and viability of the infused ASCs, as evidenced by low signal intensity onT2 weighted images at the level of the right thyroid cartilage. Conclusions: Infusion of ASCs improved laryngeal regeneration of surgically induced cartilaginous defects while decreasing fibrous tissue formation in this in vivo rabbit model. Furthermore, magnetic resonance imaging was shown to be a useful, noninvasive method to track correct ASCs placement and viability in cartilage regeneration in this animal model.

Comparison of chest CT scan findings between COVID-19 and pulmonary contusion in trauma patients based on RSNA criteria: Established novel criteria for trauma victims.

PROPOSE: In this study, we re-assessed the criteria defined by the radiological society of North America (RSNA) to determine novel radiological findings helping the physicians differentiating COVID-19 from pulmonary contusion. METHODS: All trauma patients with blunt chest wall trauma and subsequent pulmonary contusion, COVID-19-related signs and symptoms before the trauma were enrolled in this retrospective study from February to May 2020. Included patients (Group P) were then classified into two groups based on polymerase chain reaction tests (Group Pa for positive patients and Pb for negative ones). Moreover, 44 patients from the pre-pandemic period (Group PP) were enrolled. They were matched to Group P regarding age, sex, and trauma-related scores. Two radiologists blindly reviewed the CT images of all enrolled patients according to criteria defined by the RSNA criteria. The radiological findings were compared between Group P and Group PP; statistically significant ones were re-evaluated between Group Pa and Group Pb thereafter. Finally, the sensitivity and specificity of each significant findings were calculated. The Chi-square test was used to compare the radiological findings between Group P and Group PP. RESULTS: In the Group PP, 73.7% of all ground-glass opacities (GGOs) and 80% of all multiple bilateral GGOs were detected (p < 0.001 and p = 0.25, respectively). Single bilateral GGOs were only seen among the Group PP. The Chi-square tests showed that the prevalence of diffused GGOs, multiple unilateral GGOs, multiple consolidations, and multiple bilateral consolidations were significantly higher in the Group P (p = 0.001, 0.01, 0.003, and 0.003, respectively). However, GGOs with irregular borders and single consolidations were more significant among the Group PP (p = 0.01 and 0.003, respectively). Of note, reticular distortions and subpleural spares were exclusively detected in the Group PP. CONCLUSION: We concluded that the criteria set by RSNA for the diagnosis of COVID-19 are not appropriate in trauma patients. The clinical signs and symptoms are not always useful either. The presence of multiple unilateral GGOs, diffused GGOs, and multiple bilateral consolidations favor COVID-19 with 88%, 97.62%, and 77.7% diagnostic accuracy.

Fetal MRI in Prenatal Diagnosis of Encephalocele.

BACKGROUND: Encephalocele, a rare congenital brain malformation, is herniation of brain tissue with or without meninges through a cranial fossa defect. It is classified by location and is usually associated with other congenital anomalies. CASE: A 29-year-old G2, P1, 36-week pregnant woman was referred for fetal ultrasound delivery planning. Sonographic abnormalities led to fetal magnetic resonance imaging, which revealed a large sac of cerebrospinal fluid herniating through the anterior cranial fossa defect with strands of neurogenic tissue in direct contact with the tongue in the absence of the palate. Agenesis of the corpus callosum and the classic "Viking helmet" appearance of the frontal horns of the lateral ventricles were clearly visible. CONCLUSION: Prenatal diagnosis of encephalocele is rarely reported. Unfortunately, the infant in this case report died at 3 months of age despite intensive medical therapy.

Synthesis of highly stable and biocompatible gold nanoparticles for use as a new X-ray contrast agent.

This work reports a novel reduction procedure for the synthesis of Gum Arabic (GA) capped-gold nanoparticles (AuNPs) in glucosammonium formate as a new ionic liquid. The GA coated AuNPs show good stability in physiological media. The synthesized AuNPs were characterized by UV-Vis spectroscopy, transmission electron microscopy, dynamic light scattering and X-ray diffraction analysis. These stable AuNPs are introduced as a new contrast agent for X-ray Computed Tomography (X-ray CT). These nanoparticles have higher contrasting properties than the commercial contrast agent, Visipaque. The precursors used (Gum Arabic and glucose based-ionic liquid) for synthesis of AuNPs are biocompatible and non-toxic.

A versatile theranostic magnetic polydopamine iron oxide NIR laser-responsive nanosystem containing doxorubicin for chemo-photothermal therapy of melanoma.

Theranostics nanoparticles (NPs) have recently received much attention in cancer imaging and treatment. This study aimed to develop a multifunctional nanosystem for the targeted delivery of photothermal and chemotherapy agents. Fe3O4 NPs were modified with polydopamine, bovine serum albumin, and loaded with DOX via a thermal-cleavable Azo linker (Fe3O4@PDA@BSA-DOX). The size of Fe3O4@PDA@BSA NPs was approximately 98 nm under the desired conditions. Because of the ability of Fe3O4 and PDA to convert light into heat, the temperature of Fe3O4@PDA@BSA NPs increased to approximately 47 °C within 10 min when exposed to an 808 nm NIR laser with a power density of 1.5 W/cm2. The heat generated by the NIR laser leads to the breaking of AZO linker and drug release. In vivo and in vitro results demonstrated that prepared NPs under laser irradiation successfully eradicated tumor cells without any significant toxicity effect. Moreover, the Fe3O4@PDA@BSA NPs exhibited the potential to function as a contrasting agent. These NPs could accumulate in tumors with the help of an external magnet, resulting in a significant enhancement in the quality of magnetic resonance imaging (MRI). The prepared novel multifunctional NPs seem to be an efficient system for imaging and combination therapy in melanoma.

Differential privacy preserved federated learning for prognostic modeling in COVID-19 patients using large multi-institutional chest CT dataset.

BACKGROUND: Notwithstanding the encouraging results of previous studies reporting on the efficiency of deep learning (DL) in COVID-19 prognostication, clinical adoption of the developed methodology still needs to be improved. To overcome this limitation, we set out to predict the prognosis of a large multi-institutional cohort of patients with COVID-19 using a DL-based model. PURPOSE: This study aimed to evaluate the performance of deep privacy-preserving federated learning (DPFL) in predicting COVID-19 outcomes using chest CT images. METHODS: After applying inclusion and exclusion criteria, 3055 patients from 19 centers, including 1599 alive and 1456 deceased, were enrolled in this study. Data from all centers were split (randomly with stratification respective to each center and class) into a training/validation set (70%/10%) and a hold-out test set (20%). For the DL model, feature extraction was performed on 2D slices, and averaging was performed at the final layer to construct a 3D model for each scan. The DensNet model was used for feature extraction. The model was developed using centralized and FL approaches. For FL, we employed DPFL approaches. Membership inference attack was also evaluated in the FL strategy. For model evaluation, different metrics were reported in the hold-out test sets. In addition, models trained in two scenarios, centralized and FL, were compared using the DeLong test for statistical differences. RESULTS: The centralized model achieved an accuracy of 0.76, while the DPFL model had an accuracy of 0.75. Both the centralized and DPFL models achieved a specificity of 0.77. The centralized model achieved a sensitivity of 0.74, while the DPFL model had a sensitivity of 0.73. A mean AUC of 0.82 and 0.81 with 95% confidence intervals of (95% CI: 0.79-0.85) and (95% CI: 0.77-0.84) were achieved by the centralized model and the DPFL model, respectively. The DeLong test did not prove statistically significant differences between the two models (p-value = 0.98). The AUC values for the inference attacks fluctuate between 0.49 and 0.51, with an average of 0.50 ± 0.003 and 95% CI for the mean AUC of 0.500 to 0.501. CONCLUSION: The performance of the proposed model was comparable to centralized models while operating on large and heterogeneous multi-institutional datasets. In addition, the model was resistant to inference attacks, ensuring the privacy of shared data during the training process.

Hydatid Disease: A Pictorial Review of Uncommon Locations.

Hydatid disease is a zoonotic infection caused primarily by the tapeworm parasite, Echinococcus granulosus. It is considered an endemic disease in the Mediterranean region.  In about 90% of cases, hydatid cysts are found in the liver and lungs; however, any other organ in the body may be affected, particularly in endemic areas. When encountering cystic lesions in these areas, the physician should always keep hydatid disease as a possible diagnosis in mind. To avoid life-threatening conditions such as anaphylactic shock or pressure effect on vital organs, timely diagnosis, and proper management are critical. When a rare site is involved, hydatid disease should be diagnosed using a combination of serologic assays and imaging modalities such as ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI). These imaging modalities can also be used to determine the extent of the disease and assess possible complications. Here, we present a pictorial review of typical imaging manifestations of hydatid cysts in unusual sites. Being aware of these imaging features will assist physicians in making an accurate, timely diagnosis and subsequently, providing optimal management.

Glucosamine-Modified Mesoporous Silica-Coated Magnetic Nanoparticles: A "Raisin-Cake"-like Structure as an Efficient Theranostic Platform for Targeted Methotrexate Delivery.

This study presents the synthesis of glucosamine-modified mesoporous silica-coated magnetic nanoparticles (MNPs) as a therapeutic platform for the delivery of an anticancer drug, methotrexate (MTX). The MNPs were coated with mesoporous silica in a templated sol-gel process to form MNP@MSN, and then chloropropyl groups were added to the structure in a post-modification reaction. Glucosamine was then reacted with the chloro-modified structure, and methotrexate was conjugated to the hydroxyl group of the glucose. The prepared structure was characterized using techniques such as Fourier transform infrared (FT-IR) spectroscopy, elemental analysis (CHN), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), a vibrating sample magnetometer (VSM), and X-ray diffraction (XRD). Good formation of nano-sized MNPs and MNP@MSN was observed via particle size monitoring. The modified glucosamine structure showed a controlled release profile of methotrexate in simulated tumor fluid. In vitro evaluation using the 4T1 breast cancer cell line showed the cytotoxicity, apoptosis, and cell cycle effects of methotrexate. The MTT assay showed comparable toxicity between MTX-loaded nanoparticles and free MTX. The structure could act as a glucose transporter-targeting agent and showed increased uptake in cancer cells. An in vivo breast cancer model was established in BALB/C mice, and the distribution of MTX-conjugated MNP@MSN particles was visualized using MRI. The MTX-conjugated particles showed significant anti-tumor potential together with MRI contrast enhancement.

False-Positive Radioiodine Uptake From an Intracranial Surgical Clip.

ABSTRACT: A 73-year-old man with papillary thyroid cancer underwent total thyroidectomy and bilateral neck dissections. He was subsequently treated with 131I. The posttherapy scan showed radioiodine uptake at the left supraorbital region, which localized to a metallic surgical clip. There was no evidence of metastasis in this area. This is not a commonly reported finding. Knowledge of this false-positive finding can help avoid unnecessary workup and treatment.

Schwannoma of the Rectosigmoid Colon.

Schwannoma is a rare tumor in the colon which originates from the peripheral nerve plexus. Most of the cases have been asymptomatic but occasionally present as an obstructive mass. Abdominal investigations are effective in some cases, but usually, they are not informative. A significant number of cases have been detected after their operation by histopathology examination. Immune and histochemical staining shows the spindle cells that have been positive for S-100 and vimentin, but negative for CD34 and smooth muscle actin. If the diagnosis of Schowannoma is confirmed preoperatively, segmental resection is recommended. In this case report, we presented a 58-year-old woman with pelvic mass and normal colonoscopy that mimic extramural large uterine myoma with extraluminal pressure effect on the rectosigmoid.

A case of aqueductal obstruction by web with no sign except a headache.

Aqueductal stenosis can be a silent disease that can present in a patient for years without any signs and symptoms. This silence can occur due to CSF flow dynamics compensation, and it can continue until the increase in CSF production so that the symptoms may appear during adolescence or even later. In this study, we report an aqueduct obstruction by web, who had no symptoms except a headache and was referred for MRI in his early thirty. The patient was referred to find the cause of his episodes of headaches. If he did not follow up on his headache, he might never know about his disorder.

Currarino syndrome as an incidental radiologic finding in a patient with acute flank pain: A case report.

Currarino syndrome is an autosomal dominant hereditary disease defined as a triad of anorectal abnormality, sacral dysgenesis, and a presacral mass, primarily an anterior sacral meningocele. It is often seen in children and considered rare in adults. It is mostly found as an incidental finding. We present a 21-year-old man who presented with acute flank pain. He had a history of Hirschsprung's disease and therefore had undergone surgery in his infancy. He also had a history of prolonged constipation and had an episode of admission due to suspected obstruction. On physical examination, he had a severe costovertebral angle tenderness. urine exam revealed microscopic hematuria. Laboratory tests were otherwise unremarkable. Computed tomography scan revealed renal stones as well as a horseshoe kidney. Incidental findings included a large simple cystic structure in the presacral area suggestive of an anterior meningocele and sacral dysgenesis associated with scimitar sacral appearance. These findings suggested a diagnosis of Currarino syndrome. Urinary complications of this disease are reported in few articles. An important takeaway note for physicians is to have a high level of suspicion when encountering patients with gastrointestinal, neurologic, or urologic signs and symptoms and consider a thorough history taking and physical examination alongside proper imaging evaluation.

Acute disseminated encephalomyelitis (ADEM) after SARS- CoV-2 vaccination: A case report.

Acute disseminated encephalomyelitis (ADEM) is an acute demyelinating disorder of the central nervous system that is ordinarily monophasic. ADEM can develop following infection or vaccination. Here, we present a 37 y/o male patient with progressive muscle weakness in all limbs along with dysphagia following COVID-19 vaccination. Brain magnetic resonance imaging (MRI) revealed typical imaging findings which presented as multifocal T2-FLAIR signal changes in the corticospinal tract, pons, and temporal lobe with diffusion restriction. Magnetic resonance spectroscopy (MRS) further confirmed the diagnosis by the typical elevation of the Choline and Myoinositol peaks. Neurologic impairments have been reported as the potential side effects of COVID-19 vaccines. Appropriate imaging modalities together with a thorough clinical examination are essential for making a correct diagnosis.

Incidental diagnosis of a rare endobronchial schwannoma in a 7-year-old girl: A case report.

Schwannomas are nerve sheath tumors that arise from Schwann cells and are mainly benign. The likelihood of endobronchial schwannoma amongst all intrapulmonary tumors is up to 0.2% and mainly presents late. This study described a pediatric endobronchial schwannomas case discovered incidentally during rigid bronchoscopy. This case is uncommon, and its report can help physicians diagnose the same cases. The case was a 7-year-old girl presenting with fever and cough who had no history of pulmonary disease or relevant family history. Physical examination, chest radiography, CT scan, and bronchoscopy were performed on the patient. A biopsy was taken from the observed mass obstructing the bronchus during bronchoscopy. The mass was resected. Pathology revealed low-grade spindle cell neoplasm and confirmed schwannoma in immunohistochemistry. Endobronchial schwannomas can happen in children presenting with simple symptoms. For benign lesions, the prognosis is generally good. Due to the slow growth of these tumors and the potential for recurrence after resection, long-term follow-up may be needed.

Evaluation of Ultra-Low-Dose Chest Computed Tomography Images in Detecting Lung Lesions Related to COVID-19: A Prospective Study.

Background: The present study aimed to evaluate the effectiveness of ultra-low-dose (ULD) chest computed tomography (CT) in comparison with the routine dose (RD) CT images in detecting lung lesions related to COVID-19. Methods: A prospective study was conducted during April-September 2020 at Shahid Faghihi Hospital affiliated with Shiraz University of Medical Sciences, Shiraz, Iran. In total, 273 volunteers with suspected COVID-19 participated in the study and successively underwent RD-CT and ULD-CT chest scans. Two expert radiologists qualitatively evaluated the images. Dose assessment was performed by determining volume CT dose index, dose length product, and size-specific dose estimate. Data analysis was performed using a ranking test and kappa coefficient (κ). P<0.05 was considered statistically significant. Results: Lung lesions could be detected with both RD-CT and ULD-CT images in patients with suspected or confirmed COVID-19 (κ=1.0, P=0.016). The estimated effective dose for the RD-CT protocol was 22-fold higher than in the ULD-CT protocol. In the case of the ULD-CT protocol, sensitivity, specificity, accuracy, and positive predictive value for the detection of consolidation were 60%, 83%, 80%, and 20%, respectively. Comparably, in the case of RD-CT, these percentages for the detection of ground-glass opacity (GGO) were 62%, 66%, 66%, and 18%, respectively. Assuming the result of real-time polymerase chain reaction as true-positive, analysis of the receiver-operating characteristic curve for GGO detected using the ULD-CT protocol showed a maximum area under the curve of 0.78. Conclusion: ULD-CT, with 94% dose reduction, can be an alternative to RD-CT to detect lung lesions for COVID-19 diagnosis and follow-up.An earlier preliminary report of a similar work with a lower sample size was submitted to the arXive as a preprint. The preprint is cited as: https://arxiv.org/abs/2005.03347.