Current concepts on magnetic resonance imaging (MRI) perfusion-diffusion assessment in acute ischaemic stroke: a review & an update for the clinicians

Recently, several medical societies published joint statements about imaging recommendations for acute stroke and transient ischaemic attack patients. In following with these published guidelines, we considered it appropriate to present a brief, practical and updated review of the most relevant concepts on the MRI assessment of acute stroke. Basic principles of the clinical interpretation of diffusion, perfusion, and MRI angiography (as part of a global MRI protocol) are discussed with accompanying images for each sequence. Brief comments on incidence and differential diagnosis are also included, together with limitations of the techniques and levels of evidence. The purpose of this article is to present knowledge that can be applied in day-to-day clinical practice in specialized stroke units or emergency rooms to attend patients with acute ischaemic stroke or transient ischaemic attack according to international standards

Correlation between Chest X-Ray Severity in COVID-19 and Age in Mexican-Mestizo Patients: An Observational Cross-Sectional Study

Introduction. Chest X-ray (CXR) is used for the initial triage of patients with suspected COVID-19. Studies of CXR scoring in the European population found a higher score in males than in females and significantly correlated with age. Because there have not been studies in the Mexican-mestizo community, we aimed to compare the differences in CXR scores between males and females and their correlation with age after controlling comorbidities like diabetes and hypertension. Materials and Methods. A retrospective study of 1000 CXR of Mexican-mestizo patients with SARS-CoV-2 infection, confirmed by RT-PCR. Significant differences between age, age groups, symptoms, comorbidities, and CXR scores between males and females used the Mann–Whitney U, Chi-square tests (χ2), and Kruskal–Wallis tests. The relationship between the total CXR score and age was measured with the Spearman rank correlation coefficient (Rs); partial correlation analysis controlled the effect of symptoms, risk factors, and comorbidities. Results. The total CXR score did not show a difference between males and females grouped by age. There was a positive, low correlation between the total CXR score and age in males, Rs=0.260, p<0.001 (N=616), and in females, Rs=0.170, p=0.001 (N=384). Age only explained a <9% variance of CXR severity. Rs decreased its magnitude (from Rs=0.152 to Rs=0.046) and lost its significance (change in p value from p<0.001 to p=0.145) after controlling the effect of hypertension. Conclusions. There is no significant difference in CXR score between males and females in the Mexican-mestizo population grouped by age. Hypertension cancels the significance of CXR severity with age pointing to its role in the pathophysiology of COVID-19. Further research using stratified groups by age and gender in other populations needs to be published

Comparison between Mexican and International Medical Graduates’ scores in the ENARM Competing for Clinical Specialities in Mexico during 2012-2019: Data Visualization, Trends and Forecasting Analyses

Objectives: Because there is heterogeneity in the ENARM scores obtained between Mexicans and International medical graduates (IMG) in the eight clinical specialities with direct-entry (Anesthesiology, and Emergency Medicine. Geriatrics, Internal Medicine, Medical Genetics, Pediatrics, Pneumology, Psychiatry), we aimed to evaluate those scores. We hypothesized that Mexican test-takers achieve higher scores than IMG with significant growth trends in their exam scores. Methods: This study was cross-sectional, used historical data from the annual public report of the ENARM for eight years (2012 to 2019). We compare the minimum (MinSco) and maximum (MaxSco) scores of each speciality using ANOVA. Mexican versus IMG scores were evaluated with an independent student t-test, trends with Spearman’s correlation coefficient, and a 5-years forecasting trend. Results: There was a significant difference among the MinSco for five surgical specialities; F (7, 115) = 26.611, p = &lt; .001; the global mean of MinSco was 69.133; specialities above this mean were Internal Medicine, Anesthesiology, Pediatrics, and Pneumology. The global mean for MaxSco was 79.422; five specialities were above: Internal Medicine, Pneumology, Geriatrics, Psychiatry, and Medical Genetics. We did not find a significant difference in the MinSco between Mexicans and IMG, but a significant difference was found in the MaxSco between both groups. Conclusions: ENARM represents a market of high-performance test-takers across the clinical specialities. Mexicans and IMG achieved similar entrance scores, but Mexicans showed a higher MaxSco over IMG in all clinical specialities

Comparison between Mexican and International Medical Graduates’ scores in the ENARM Competing for Clinical Specialities in Mexico during 2012-2019: Data Visualization, Trends and Forecasting Analyses

Objectives: Because there is heterogeneity in the ENARM scores obtained between Mexicans and International medical graduates (IMG) in the eight clinical specialities with direct-entry (Anesthesiology, and Emergency Medicine. Geriatrics, Internal Medicine, Medical Genetics, Pediatrics, Pneumology, Psychiatry), we aimed to evaluate those scores. We hypothesized that Mexican test-takers achieve higher scores than IMG with significant growth trends in their exam scores. Methods: This study was cross-sectional, used historical data from the annual public report of the ENARM for eight years (2012 to 2019). We compare the minimum (MinSco) and maximum (MaxSco) scores of each speciality using ANOVA. Mexican versus IMG scores were evaluated with an independent student t-test, trends with Spearman’s correlation coefficient, and a 5-years forecasting trend. Results: There was a significant difference among the MinSco for five surgical specialities; F (7, 115) = 26.611, p = &lt; .001; the global mean of MinSco was 69.133; specialities above this mean were Internal Medicine, Anesthesiology, Pediatrics, and Pneumology. The global mean for MaxSco was 79.422; five specialities were above: Internal Medicine, Pneumology, Geriatrics, Psychiatry, and Medical Genetics. We did not find a significant difference in the MinSco between Mexicans and IMG, but a significant difference was found in the MaxSco between both groups. Conclusions: ENARM represents a market of high-performance test-takers across the clinical specialities. Mexicans and IMG achieved similar entrance scores, but Mexicans showed a higher MaxSco over IMG in all clinical specialities

Pre-operative apparent diffusion coefficient values and tumour region volumes as prognostic biomarkers in glioblastoma: correlation and progression-free survival analyses

Abstract Objectives Glioblastoma (GB) contains diverse histologic regions. Apparent diffusion coefficient (ADC) values are surrogates for the degree of number of cells within the tumour regions. Because an assessment of ADC values and volumes within tumour sub-compartments of GB is missing in the literature, we aimed to evaluate these associations. Methods A retrospective cohort of 48 patients with GB underwent segmentation to calculate tumour region volumes (in cubic centimetre) and ADC values in tumour regions: normal tissue, enhancing tumour, proximal oedema, distal oedema, and necrosis. Correlation, Kaplan-Meier, and Cox hazard regression analyses were performed. Results We found a statistically significant difference among ADC values for tumour regions: F (4, 220) = 166.71 and p ≤ .001 and tumour region volumes (necrosis, enhancing tumour, peritumoural oedema): F (2, 141) = 136.3 and p ≤ .001. Post hoc comparisons indicated that the only significantly different mean score was the peritumoural volume in oedema region (p < .001). We observed a positive significant correlation between ADC of distal oedema and peritumoural volume, r = .418, df = 34, and p = .011. Cox proportional hazards regression analysis considering only tumour region volumes provided an almost significant model: − 2 log-likelihood = 146.066, χ 2 (4) = 9.303, and p = .054 with a trend towards significance of the hazard function: p = .067 and HR = 1.077 for the non-enhancing tumour volume. Conclusions ADC values together with volumes of oedema region might have a role as predictors of progression-free survival (PFS) in patients with GB; we recommend a routine MRI assessment with the calculation of these biomarkers in GB

Imaging techniques for assessing hepatic fat content in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD), an emerging clinical entity with worldwide recognition, is today the most common cause of abnormal liver function tests among adults in the United States. In Mexico City, its prevalence has been reported by our group to be around 14%, but its incidence is higher in the hispanic population in the United States (hispanic population 45%, white population 33%, black population 24%). The main issues in the diagnosis, follow-up, and management of NAFLD are our limited understanding of its pathophysiology and the difficulties involved in developing a noninvasive diagnostic method. Several imaging techniques can detect fatty infiltration of the liver, each with its own advantages and disadvantages. Ultrasound is still in the first option for diagnosis, but its accuracy depends on the operator and the patient’s features. Computed tomography can detect hepatic fat content, but only at a threshold of 30%, and it involves ionizing radiation. Magnetic resonance (MR) spectroscopy is probably the most accurate and fastest method of detecting fat, but it is expensive and the necessary software is still not easily available in most MRI units. MR elastography, a new technique to detect liver stiffness, has not been demonstrated to detect NAFLD, and is still undergoing research in patients with hepatitis and cirrhosis. In conclusion, all these imaging tools are limited in their ability to detect coexisting inflammation and fibrosis. In this review, we discuss the radiological techniques currently used to detect hepatic fat content

Correlations between DTI-derived metrics and MRS metabolites in tumour regions of glioblastoma: a pilot study

Specific correlations among diffusion tensor imaging (DTI)-derived metrics and magnetic resonance spectroscopy (MRS) metabolite ratios in brains with glioblastoma are still not completely understood

Imaging Assessment of the Postoperative Spine: An Updated Pictorial Review of Selected Complications

Imaging of the postoperative spine requires the identification of several critical points by the radiologist to be written in the medical report: condition of the underlying cortical and cancellous bone, intervertebral disc, and musculoskeletal tissues; location and integrity of surgical implants; evaluation of the success of decompression procedures; delineation of fusion status; and identification of complications. This article presents a pictorial narrative review of the most common findings observed in noninstrumented and instrumented postoperative spines. Complications in the noninstrumented spine were grouped in early (hematomas, pseudomeningocele, and postoperative spine infection) and late findings (arachnoiditis, radiculitis, recurrent disc herniation, spinal stenosis, and textiloma). Complications in the instrumented spine were also sorted in early (hardware fractures) and late findings (adjacent segment disease, hardware loosening, and implant migration). This review also includes a short description of the most used diagnostic techniques in postoperative spine imaging: plain radiography, ultrasound (US), computed tomography (CT), magnetic resonance (MR), and nuclear medicine. Imaging of the postoperative spine remained a challenging task in the early identification of complications and abnormal healing process. It is crucial to consider the advantages and disadvantages of the imaging modalities to choose those that provide more accurate spinal status information during the follow-up. Our review is directed to all health professionals dealing with the assessment and care of the postoperative spine