COVID-19 pandemic revisited: lessons the radiology community has learned a year later.

For more than 1 year, COVID-19 pandemic has impacted every aspect of our lives. This paper reviews the major challenges that the radiology community faced over the past year and the impact the pandemic had on the radiology practice, radiologist-in-training education, and radiology research. The lessons learned from COVID-19 pandemic can help the radiology community to be prepared for future outbreaks and new pandemics, preserve good habits, enhance cancer screening programs, and adapt to the changes in radiology education and scientific meetings.

Posterior Reversible Encephalopathy Syndrome after Allogeneic Stem Cell Transplantation in Pediatric Patients with Fanconi Anemia, a Prospective Study.

Posterior reversible encephalopathy syndrome (PRES) is one of the most common neurologic complications following hematopoietic stem cell transplantation (HSCT). We aimed to evaluate the incidence, clinical, and imaging features of PRES in pediatric patients with Fanconi anemia (FA) following HSCT. This prospective study included all post-HSCT patients with underlying FA disease between 2014 and 2017. Brain computed tomography scan and magnetic resonance imaging (MRI) were performed in all individuals who developed neurologic symptoms. PRES was diagnosed based on clinic-radiological evidence. Follow-up MRI was performed in all patients with PRES within two months. Forty-one patients with FA (28 males; mean age, 8.19 ± 3.25 years) were enrolled. Out of 15 patients with acute neurologic symptoms, PRES was diagnosed in 9 individuals (21.95% of the total cohort). The occurrence of PRES was significantly higher in patients who had a donor with a 1-locus mismatch (P= .02). Donor relation, stem cell source, and graft-versus-host disease grade did not have any significant association with the development of PRES. MRI showed asymmetric vasogenic edema in 5 patients, an overt infarct in 1 patient, and foci of microhemorrhages in 3 patients, 1 of whom developed a hemorrhagic infarct. This patient died shortly, and persistent microhemorrhages were noted in the other 2 patients. Our findings demonstrate a greater risk of developing PRES after HSCT in patients with FA compared with those with other diseases (21.95% versus 1% to 10%), and in contrast to its term, it might be irreversible and has adverse effects on HSCT outcomes. The increased vascular and endothelial fragility in FA may contribute to the higher frequency of PRES in these individuals.

Radiology Perspective of Coronavirus Disease 2019 (COVID-19): Lessons From Severe Acute Respiratory Syndrome and Middle East Respiratory Syndrome.

OBJECTIVE. Since the outbreak of the novel coronavirus pulmonary illness coronavirus disease 2019 (COVID-19) in China, more than 79,000 people have contracted the virus worldwide. The virus is rapidly spreading with human-to-human transmission despite imposed precautions. Because similar pulmonary syndromes have been reported from other strains of the coronavirus family, our aim is to review the lessons from imaging studies obtained during severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) outbreaks. CONCLUSION. The review of experiences with the MERS and SARS outbreaks will help us better understand the role of the radiologist in combating the outbreak of COVID-19. The known imaging manifestations of the novel coronavirus and the possible unknowns will also be discussed.

Potential MR Enterography Features to Differentiate Primary Small Intestinal Lymphoma From Crohn Disease.

OBJECTIVE. The purpose of this study was to assess the MR enterographic features of primary small intestinal lymphoma (PSIL) and compare them with active Crohn disease (CD) presenting with severe (≥ 10 mm) mural thickening of the small bowel. MATERIALS AND METHODS. This retrospective study included 15 patients with pathologically proven PSIL and 15 patients with active inflammatory CD with severe mural thickening. Various morphologic, enhancement, and diffusion parameters were compared between the two groups at MR enterography. The ratios of the upstream to involved luminal diameter and mural thickness to luminal diameter in the involved segment were calculated. An attempt was made to define a predictive model (morphologic score) for discriminating PSIL from CD with severe mural thickening. RESULTS. Patients with PSIL were more likely than those with CD to have unifocal disease (66.7% vs 20.0%, p = 0.025), circumferential involvement (86.7% vs 26.7%, p < 0.001), luminal dilatation (60.0% vs 7.0%, p = 0.005), and an attenuated fold pattern (53.3% vs none, p < 0.001). They were less likely to have serosal surface involvement (40.0% vs 100%, p = 0.001) and mesenteric fat infiltration (33.3% vs 100%, p < 0.001). Median upstream to involved luminal diameter ratio (1.5 vs 9.6, p < 0.001) and mural thickness to involved luminal diameter ratio (1.1 vs 4.3, p = 0.044) were significantly lower in patients with PSIL than in those with CD with severe mural thickening. No significant difference was observed in enhancement and diffusion measures. Morphologic score was based on the presence of luminal dilatation, unifocal involvement, mesenteric fat infiltration, and luminal stricture, yielding accuracy of 98% for differentiation between PSIL and CD with severe mural thickening. CONCLUSION. Morphologic features seen at MR enterography rather than enhancement or diffusion parameters may be valuable for differentiation of PSIL from active CD with severe mural thickening with significantly lower ratios of upstream to involved luminal diameter and mural thickness to involved luminal diameter in PSIL.

MR enterography in nonresponsive adult celiac disease: Correlation with endoscopic, pathologic, serologic, and genetic features.

PURPOSE: To assess small bowel abnormalities on magnetic resonance enterography (MRE) in adult patients with nonresponsive celiac disease (CD) and investigate their associations with endoscopic, histopathologic, serologic, and genetic features. MATERIALS AND METHODS: This prospective study was carried out between September 2012 and August 2013. After approval by the Ethics Committee of our institution, informed consent was acquired from all participants. Forty consecutive patients with nonresponsive CD, aged 17-76 years, underwent MRE using a 1.5T unit. Sequences included T2 -HASTE, True-FISP, pre- and postcontrast VIBE to assess the quantitative (number of ileal and jejunal folds) and qualitative (fold pattern abnormalities, mural thickening, increased enhancement, bowel dilatation, or intussusception) measures. Endoscopic manifestations were categorized as normal/mild vs. severe. Histopathological results were divided into mild and severe. Genotyping of HLA-DQ2 and DQ8 was performed. Serum levels of tissue-transglutaminase, endomysial, and gliadin antibodies were also determined. Logistic regression analysis and receiver operating characteristic (ROC) curve were used. RESULTS: Twenty-nine (72.5%) cases showed abnormal MRE. Reversed jejunoileal fold pattern had significant association with severe endoscopic (odds ratio [OR] = 8.38, 95% confidence interval [CI] 1.73-40.5) and pathologic features (OR = 7.36, 95% CI 1.33-40.54). An increased number of ileal folds/inch was significantly associated with severe MARSH score and positive HLA-DQ8. (P < 0.001 and P = 0.026, respectively). Ileal fold number had the highest areas under the curve for prediction of severe endoscopic (AUC: 0.75, P = 0.009) and pathologic (AUC: 0.84, P < 0.001) findings and positive anti-transglutaminase antibody (AUC: 0.85, P = 0.027). CONCLUSION: Fold pattern reversal on MRE is highly associated with endoscopic and pathologic features of refractory celiac disease (RCD). Increased ileal folds showed higher correlation with endoscopic-pathologic features, HLA-DQ8, and anti-transglutaminase level. MRE might be more sensitive for detection of increased ileal folds in CD rather than reduction of duodenal and jejunal folds due to better distension of ileal loops. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2017;46:1096-1106.

Radiologic resolution of malignant infantile osteopetrosis skeletal changes following hematopoietic stem cell transplantation.

INTRODUCTION: Hematopoietic stem cell transplantation (HSCT) is the only known curative treatment of malignant infantile osteopetrosis (MIOP). In this study, short-term serial bone surveys were used to assess radiologic evolution of skeletal changes after HSCT in MIOP. MATERIALS AND METHODS: Baseline whole-body bone survey was performed in all patients. HSCT was successful in 14 patients (11 with full chimerism, three with mixed chimerism) in whom follow-up bone surveys were carried out at 6 and 12 months after HSCT. RESULTS: Normal corticomedullary differentiation was evident in five (P = 0.06) and 12 (P < 0.005) patients at 6 and 12 months, respectively. Abnormal endobone appearance in long bones, present in 11 participants at baseline exam, disappeared in eight (P = 0.008) and all (P = 0.001) patients at 6 and 12 months, respectively. In 6-month follow-up, rachitic changes significantly disappeared (P < 0.01) in long bones; however, they were evident in ribs of 12 patients (P = 0.50). No patient had rickets in ribs or long bones after 12 months. CONCLUSION: We observed considerable resolution of MIOP skeletal changes after HSCT in all patients with either full or mixed chimerism. Rachitic changes in long bones, attenuated corticomedullary differentiation, and endobone appearance were the first to resolve. We propose using single long bone plain x-ray to demonstrate short-term skeletal response to HSCT.

Gallstone disease and obesity: a population-based study on abdominal fat distribution and gender differences.

BACKGROUND: Existing evidence suggests the visceral fat is more metabolically active than subcutaneous fat. We aimed to investigate the value of subcutaneous (SAT) and visceral adipose tissue thickness (VAT) for prediction of gallstone disease (GSD) in general population by focus on gender differences and comparison with body mass index (BMI), waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR). MATERIAL AND METHODS: In this cross-sectional survey, 1,494 subjects (51.4 % men), aged above 50, randomly selected from Golestan Cohort Study residing in Gonbad City, Iran, underwent anthropometric measurements and abdominal ultrasonography. RESULTS: Prevalence of GSD was 17.8% (95% CI 15.9-19.8). Following adjustment for age and then other potential risk factors, all obesity indices, except for SAT, were associated with GSD in women with the highest odds ratio observed in WHtR (OR 1.52, 95% CI 1.22-1.89). In contrast, WHR was the only associated index in men (OR 1.49, 95% CI 1.08-2.06). The trend of increasing obesity measures across the quartiles with the risk of GSD was significant in subgroups of WHtR and BMI in women and WHR in men. No significant association was found between SAT and GSD in men or women. CONCLUSIONS: The best anthropometric indicators of the risk of GSD may differ by gender. In men, WHR might be the only preferred index to estimate risk of GSD. WHtR, WHR, VAT and BMI are associated with GSD risk in women, although WHtR might better explain this risk. SAT is the poor indicator for identifying subjects with GSD in both genders.

Evaluation of ChatGPT-Generated Educational Patient Pamphlets for Common Interventional Radiology Procedures.

RATIONALE AND OBJECTIVES: This study aimed to evaluate the accuracy and reliability of educational patient pamphlets created by ChatGPT, a large language model, for common interventional radiology (IR) procedures. METHODS AND MATERIALS: Twenty frequently performed IR procedures were selected, and five users were tasked to independently request ChatGPT to generate educational patient pamphlets for each procedure using identical commands. Subsequently, two independent radiologists assessed the content, quality, and accuracy of the pamphlets. The review focused on identifying potential errors, inaccuracies, the consistency of pamphlets. RESULTS: In a thorough analysis of the education pamphlets, we identified shortcomings in 30% (30/100) of pamphlets, with a total of 34 specific inaccuracies, including missing information about sedation for the procedure (10/34), inaccuracies related to specific procedural-related complications (8/34). A key-word co-occurrence network showed consistent themes within each group of pamphlets, while a line-by-line comparison at the level of users and across different procedures showed statistically significant inconsistencies (P < 0.001). CONCLUSION: ChatGPT-generated education pamphlets demonstrated potential clinical relevance and fairly consistent terminology; however, the pamphlets were not entirely accurate and exhibited some shortcomings and inter-user structural variabilities. To ensure patient safety, future improvements and refinements in large language models are warranted, while maintaining human supervision and expert validation.

Evaluation of the efficacy of once-daily use of tadalafil vs. on-demand use. Is there a cumulative effect?

OBJECTIVE: To assess and compare the efficacy of on-demand versus daily dosages of tadalafil in the treatment of erectile dysfunction. METHODS: The case-control double-blind study was conducted at the Department of Urology, Tehran University of Medical Science, Imam Khomeini Hospital, from March 2008 to January 2010. It comprised 100 males suffering from erectile dysfunction who were randomised into two groups; one receiving on-demand tadalafil (10mg), and the other receiving once-daily dose of tadalafil (10mg). The erectile function domain of the International Index of Erectile Function was evaluated initially at the baseline and then at 24 weeks after treatment. To evaluate the possible cumulative effect of tadalafil, the index was measured in the group taking daily tadalafil at 12 weeks after the initiation of the treatment. SPSS 13 was used for statistical analysis. RESULTS: The study showed significant improvement in the mean erectile function domain measured after 24 weeks in both daily (17.08+/-3.896 vs baseline 12.64+/-2.92; p<0.001) and on-demand (15.46+/-3.64 vs baseline 13.48+/-2.86; p<0.001) groups. Data showed significant difference in mean scores between on-demand and daily groups (p = 0.03). In daily group, the mean domain measured at the 24th week showed significant improvement compared to the mean score of the 12th week (p <0.001). CONCLUSION: Treatment with daily tadalafil was associated with a significantly higher erectile function domain score compared to the on-demand use. The significant difference between mean scores of 12th week and 24th week in the daily group points towards the possible cumulative effect of tadalafil.

Image-Guided Biopsies and Interventions of Mediastinal Lesions.

Optimal assessment of the mediastinal masses is performed by a combination of clinical, radiological and often histological assessments. Image-guided transthoracic biopsy of mediastinal lesions is a minimally invasive and reliable procedure to obtain tissue samples, establish a diagnosis and provide a treatment plan. Biopsy can be performed under Computed Tomography, MRI, or ultrasound guidance, using a fine needle aspiration or a core-needle. In this paper, we review the image-guided strategies and techniques for histologic sampling of mediastinal lesions, along with the related clinical scenarios and possible procedural complications. In addition, image-guided mediastinal drainage and mediastinal ablations will be briefly discussed.

Evaluation of cross-sectional imaging features that aid in the differentiation of benign and malignant splenic lesions.

PURPOSE: This study aimed to investigate the role of cross-sectional imaging in differentiating between benign and malignant splenic lesions based on various imaging features. METHODS: Database of imaging reports from January 2015 to December 2017 were searched dedicatedly for "spleen" or "splenic" terms to identify patients with splenic lesions found either on CT or MRI. The study cohort consisted of patients who had available histological reports or had follow-up imaging for a minimum of one year. Patients were categorized into the benign subcohort if they did not have a history of extra-splenic malignancy, and had a splenic lesion(s) falling into one of these categories: benign histopathology on biopsy, stable size and enhancement, or decreased size on follow-up imaging. Those who had malignant histopathology on biopsy were included in the malignant subcohort. Various morphologic features and enhancement patterns of these lesions were carefully reviewed by two radiologists who were blinded to the final histopathologic diagnosis. RESULTS: We identified 161 patients (54 % males, mean age ± SD = 59.7 ± 15.4) including 124 (77 %) in the benign and 37 (23 %) in the malignant subcohort. Benign lesions were more likely to be cystic (21.7 % vs 2.7 %, p < 0.001), homogenous (59.7 % vs. 29.7 %, p = 0.001) and to demonstrate well-defined borders (69.3 % vs. 29.7 % p= <0.001). Malignant lesions had significantly larger diameter (median size: 15 vs 11 mm, p = 0.03). Restricted diffusion was not seen in any of the benign lesions; however, 50 % of malignant lesions demonstrated restricted diffusion (p = 0.003). Features such as lesion distribution, presence of calcification, splenomegaly and number of lesions were not significantly different between benign and malignant lesions. CONCLUSION: Smaller lesion diameter, well-defined border and homogeneity favor benign nature of splenic lesions while restricted diffusion should raise suspicion for malignancy.

Coronavirus (COVID-19) Outbreak: What the Department of Radiology Should Know.

In December 2019, a novel coronavirus (COVID-19) pneumonia emerged in Wuhan, China. Since then, this highly contagious COVID-19 has been spreading worldwide, with a rapid rise in the number of deaths. Novel COVID-19-infected pneumonia (NCIP) is characterized by fever, fatigue, dry cough, and dyspnea. A variety of chest imaging features have been reported, similar to those found in other types of coronavirus syndromes. The purpose of the present review is to briefly discuss the known epidemiology and the imaging findings of coronavirus syndromes, with a focus on the reported imaging findings of NCIP. Moreover, the authors review precautions and safety measures for radiology department personnel to manage patients with known or suspected NCIP. Implementation of a robust plan in the radiology department is required to prevent further transmission of the virus to patients and department staff members.

Hot Topics of Research in Musculoskeletal Imaging: PET/MR Imaging, MR Fingerprinting, Dual-energy CT Scan, Ultrashort Echo Time.

We aimed to review the latest cutting-edge trends in emerging techniques of musculoskeletal imaging. This study reviews the current status and the preliminary studies of Magnetic Resonance Fingerprinting (MRF), Ultrashort Echo Time (UTE) sequence, Positron Emission Tomography (PET)/MR and Dual-Energy CT scan (DECT) in various oncologic and non-oncologic conditions of the musculoskeletal system. The current application, current and future research trends and limitations of each imaging technique were discussed. There are substantial potentials in MRF, UTE, PET/MR and DECT for characterization of various musculoskeletal disorders. Further dedicated studies in various fields are necessary.

3T magnetic resonance spectroscopy as a powerful diagnostic modality for assessment of thyroid nodules.

OBJECTIVE: Magnetic resonance spectroscopy (MRS) is a powerful tool for structural studies of chemical compounds and biomolecules and also documented promising findings as a potential imaging technology in thyroid oncology. This prospective study was to ascertain the clinical significance of 3 Tesla MRS in the evaluation of patients with thyroid nodules (TNs) as an ancillary diagnostic technique for thyroid carcinoma. MATERIALS AND METHODS: Magnetic resonance spectroscopy at 3T at echo- times (TEs) 136 and 270 ms was carried out on 15 patients with total number of 32 TNs larger than 1 cm3, which all were surgically resected. Choline (Chol) to creatine (Cr) ratio was assessed at 136 and 270 TEs on each nodule and a receiver operating characteristic (ROC) curve was used to determine optimal cut-off point. The findings were compared with histopathology of thyroid specimens. RESULTS: There were 23 benign and 9 malignant lesions (7 papillary and 2 follicular thyroid carcinomas). The mean values of Chol/Cr at 136 and 270 TEs was 2.28 ± 3.65 and 1.52 ± 1.67 respectively and the difference between benign and malignant nodules was only significant at 136 TEs. The study revealed that Chol/ Cr ratio cut-off point of 2.5 best correlates with histopathology results (sensitivity = 75%; specificity = 100%; PPV = 100%; NPV= 92%). CONCLUSION: This preliminary study showed that 3T magnetic resonance spectroscopy might be a specific modality for the evaluation of thyroid nodules in differentiation of benign from malignant thyroid tissue. However, a larger series would give much greater confidence that this state-of-the-art technology will worth pursuing in clinical practice.

Differentiation between benign and malignant thyroid nodules using diffusion-weighted imaging, a 3-T MRI study.

BACKGROUND: Preoperative differentiation of benign from malignant thyroid nodules remains a challenge. Aims: This study assessed the accuracy of diffusion-weighted imaging (DWI) for differentiation between benign and malignant thyroid nodules. MATERIALS AND METHODS: Preoperative DWI was performed in patients with thyroid nodule by means of a 3-T scanner magnetic resonance imaging (MRI). Images were obtained at b value of 50, 500, and 1000 mm2/s to draw an ADC (apparent diffusion coefficient) map. Findings were compared with postoperative histopathologic results. Receiver operating characteristic curve was used to assess the accuracy of different cutoff points. RESULTS: Forty-one thyroid nodules (26 benign and 15 malignant) were included in this study. None of static MRI parameters such as signal intensity, heterogeneity, and nodule border was useful to discriminate between benign and malignant lesions. Mean ADC value was (1.94 ± 0.54) × 10-3 mm2/s and (0.89 ± 0.29) × 10-3 mm2/s in benign and malignant nodules, respectively (P-value < 0.005). ADC value cutoff of 1 × 10-3 mm2/s yielded an accuracy, sensitivity, and specificity of 93%, 87%, and 96% to discriminate benign and malignant nodules. CONCLUSION: DWI is highly accurate for discrimination between benign and malignant thyroid nodules.

Prevalence and Clinical Outcomes of Common Bile Duct Dilation in Patients Who Use Opium.

BACKGROUND: This study aimed to evaluate the association of various opium-related factors with common bile duct (CBD) diameter in individuals who use opium in the general population and investigate the clinical importance and long-term outcomes. MATERIALS AND METHODS: In this prospective study, 2,400 participants were randomly selected from the Golestan Cohort study. Opium consumption data were recorded. CBD diameter was measured by ultrasound. Transient elastography was performed at enrollment and 3 years later. Participants were followed up for at least 5 years. RESULTS: A total of 1,599 individuals, aged above 50 years, were enrolled and 167 subjects were users of opium. CBD diameter was significantly higher in users of opium than controls (mean ± standard deviation:5.54 ± 1.95 versus 4.74 ± 1.34mm, P < 0.001). This difference was noted with all opium types, but mostly by users of heroin (P < 0.001). Ingestion of opium caused greater CBD dilatation than inhalation (coefficient: 1.16; 95% CI: 0.05-2.27, P = 0.04 versus coefficient: 0.98; 95% CI: 0.75-1.20, P < 0.001). Transient elastography results did not show any association between fibroscan score change and CBD diameter. No major related malignancy was seen during follow-up. CONCLUSIONS: This study strengthened the evidence of an association of opium use with increased CBD diameter in a population-based setting without significantly increased risk of pancreaticobiliary malignancies or liver fibrosis. We cautiously suggest that opium-induced CBD dilatation may not require further diagnostic work-up.

Covered stents for exclusion of iatrogenic common carotid artery-internal jugular vein fistula and brachiocephalic artery pseudoaneurysm.

Covered stents have rarely been used in neuroendovascular procedures. We report the case of a 74-year-old woman with a complex iatrogenic vascular injury from attempted insertion of a hemodialysis catheter: concurrent brachiocephalic artery pseudoaneurysm and common carotid artery to internal jugular vein fistula. Both lesions were excluded successfully by using two balloon-expandable covered stents with a satisfactory short-term clinical and angiographic outcome.

Pretreatment Evaluation of Glioma.

Glioma is considered the most common type of primary central nervous system (CNS) tumor. Imaging is crucial for diagnosis, characterization, grading, and therapeutic planning of CNS gliomas. Along with a brief description of conventional computed tomography and magnetic resonance imaging techniques, this article reviews the ever-developing role of modern imaging techniques in preoperative management of CNS gliomas. It discusses current clinical applications, promising features, and limitations of each imaging method.

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.