Deep Learning Accelerated Brain Diffusion-Weighted MRI with Super Resolution Processing.

OBJECTIVES: To investigate the clinical feasibility and image quality of accelerated brain diffusion-weighted imaging (DWI) with deep learning image reconstruction and super resolution. METHODS: 85 consecutive patients with clinically indicated MRI at a 3 T scanner were prospectively included. Conventional diffusion-weighted data (c-DWI) with four averages were obtained. Reconstructions of one and two averages, as well as deep learning diffusion-weighted imaging (DL-DWI), were accomplished. Three experienced readers evaluated the acquired data using a 5-point Likert scale regarding overall image quality, overall contrast, diagnostic confidence, occurrence of artefacts and evaluation of the central region, basal ganglia, brainstem, and cerebellum. To assess interrater agreement, Fleiss' kappa (Ï°) was determined. Signal intensity (SI) levels for basal ganglia and the central region were estimated via automated segmentation, and SI values of detected pathologies were measured. RESULTS: Intracranial pathologies were identified in 35 patients. DL-DWI was significantly superior for all defined parameters, independently from applied averages (p-value <0.001). Optimum image quality was achieved with DL-DWI by utilizing a single average (p-value <0.001), demonstrating very good (80.9%) to excellent image quality (14.5%) in nearly all cases, compared to 12.5% with very good and 0% with excellent image quality for c-MRI (p-value <0.001). Comparable results could be shown for diagnostic confidence. Inter-rater Fleiss' Kappa demonstrated moderate to substantial agreement for virtually all defined parameters, with good accordance, particularly for the assessment of pathologies (p = 0.74). Regarding SI values, no significant difference was found. CONCLUSION: Ultra-fast diffusion-weighted imaging with super resolution is feasible, resulting in highly accelerated brain imaging while increasing diagnostic image quality.

Efficacy and Safety of Calcifediol in Young Adults with Vitamin D Deficiency: A Phase I, Multicentre, Clinical Trial-POSCAL Study.

Vitamin D deficiency is highly prevalent, and recent evidence suggests a possible association between vitamin D deficiency and various health conditions. The aim of this study was to assess monthly calcifediol treatments for vitamin D deficiency (or biweekly, if the deficiency was severe) in a young adult population with no associated comorbidities. This multicentre phase I trial started with a four month open-label treatment phase (TP) that included 101 participants (65% women with mean age 29.8 years). Eighty-two percent of the subjects (79/96) achieved 25(OH)D levels within the target range (20-60 ng/mL) by the end of the TP, and they were subsequently randomised and subjected to a double-blind, placebo-controlled, five month follow-up phase (FP). At the end of the FP, 89% of participants maintained vitamin D levels of >20 ng/mL with calcifediol, versus 49% with placebo (p < 0.001). Subjects receiving monthly calcifediol during both phases (n = 32) maintained 25(OH)D levels >20 ng/mL, whereas those on the placebo during the FP (n = 38) exhibited deficiency levels of 25(OH)D by the end of the study. No clinically relevant changes in bone metabolism parameters or toxic 25(OH)D levels were observed, and no serious adverse events were reported throughout the study. Calcifediol is a safe and effective treatment for vitamin D deficiency in the young adult population, but long-term use may be required to sustain optimal 25(OH)D levels.

Gender differences in self-assessed performance and stress level during training of basic interventional radiology maneuvers.

OBJECTIVES: Gender differences have been reported to influence medical training. We investigated gender differences encountered during training in interventional radiology maneuvers. METHODS: Catheter handling was analyzed under standardized conditions in 64 participants naïve to endovascular procedures (26 women, 38 men). Objective (e.g., catheter pathway, catheter movements, required time) and subjective parameters (stress level) were recorded. The NASA-Task Load Index (NASA-TLX; 1-20 points) was used to assess participants' stress levels and perceived workload. RESULTS: In the easier tasks, no significant differences between male and female participants regarding catheter handling were observed. In the most complex task, female participants took themselves more time (688 ± 363 vs. 501 ± 230 s; p = 0.02), asked for help more frequently (n = 19 vs. n = 8) and earlier than men (203 ± 94 vs. 305 ± 142 s; p = 0.049), whereas men stood out by more agitated catheter handling (6.0 ± 1.8 vs. 4.8 ± 1.6 movements/s; p = 0.005). Overall, female participants perceived tasks to be more difficult (11.5 ± 4.2 vs. 9.6 ± 3.3; p = 0.016), perceived higher stress levels (8.9 ± 4.9 vs. 6.3 ± 4.4; p = 0.037), and rated their own performance lower (9.12 ± 3.3 vs. 11.3 ± 3.3; p = 0.009). However, female participants were able to correlate self-assessed with objective parameters correctly (r between -0.555 and -0.469; p = 0.004-0.018), whereas male participants failed to correctly rate their performance (p between 0.34 and 0.73). Stress levels correlated with objective parameters in males (r between 0.4 and 0.587; p < 0.005), but not in female participants. CONCLUSION: Perceived stress levels, self-evaluation skills, and catheter handling differ greatly between untrained male and female participants trying to solve interventional radiological tasks. These gender-specific differences should be considered in interventional radiology training. CLINICAL RELEVANCE STATEMENT: As psychological aspects may influence individual working strategies gender-specific differences in self-perception while learning interventional radiology maneuvers could be essential regarding success in teaching and treatment outcomes. KEY POINTS: • After performing standardized training, 38 male and 26 female volunteers showed significant differences regarding objective and self-assessed performance, as well as in perceived workload while performing simulated endovascular catheter maneuvers. • After solving simulated endovascular radiological tasks, female participants were able to self-assess their objective performance much more accurately than male participants. • Women took more time to solve simulated endovascular tasks and asked earlier and more frequently for help than men.

Improvement of Neurovascular Imaging Using Ultra-High-Resolution Computed Tomography Angiography.

OBJECTIVE: To evaluate diagnostic image quality of ultra-high-resolution computed tomography angiography (UHR-CTA) in neurovascular imaging as compared to normal resolution CT-angiography (NR-CTA). MATERIAL AND METHODS: In this retrospective single-center study brain and neck CT-angiography was performed using an ultra-high-resolution computed tomography scanner (n = 82) or a normal resolution CT scanner (NR-CTA; n = 73). Ultra-high-resolution images were reconstructed with a 1024â€¯× 1024 matrix and a slice thickness of 0.25 mm, whereas NR-CT images were reconstructed with a 512â€¯× 512 matrix and a slice thickness of 0.5 mm. Three blinded neuroradiologists assessed overall image quality, artifacts, image noise, overall contrast and diagnostic confidence using a 4-point Likert scale. Furthermore, the visualization and delineation of supra-aortic arteries with an emphasis on the visualization of small intracerebral vessels was assessed using a cerebral vascular score, also utilizing a 4-point Likert scale. Quantitative analyses included signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), noise and the steepness of gray value transition. Radiation exposure was determined by comparison of computed tomography dose index (CTDIvol), dose length product (DLP) and mean effective dose. Interrater agreement was evaluated via determining Fleiss-Kappa. RESULTS: Ultra-high-resolution CT-angiography (UHR-CTA) yielded excellent image quality with superior quantitative (SNR: p < 0.001, CNR: p < 0.001, steepness of gray value transition: p < 0.001) and qualitative results (overall image quality: 4 (Inter quartile range (IQR) = 4-4); p < 0.001, diagnostic confidence: 4 (IQR = 4-4); p < 0.001) compared to NR-CT (overall image quality: 3 (IQR = 3-3), diagnostic confidence: 3 (IQR = 3-4)). Furthermore, UHR-CT enabled significantly superior delineation and visualization of all vascular segments, from proximal extracranial vessels to the smallest peripheral cerebral branches (e.g. , UHR-CTA PICA: 4 (3-4) vs. NR-CTA PICA: 3 (2-3); UHR-CTA P4: 4 (IQR = 3-4) vs. NR-CTA P4: 2 (IQR = 2-3); UHR-CTA M4: 4 (IQR = 4-4) vs. NR-CTA M4: 3 (IQR = 2-3); UHR-CTA A4: 4 (IQR = 3-4) vs. NR-CTA A4: 2 (IQR = 2-3); all p < 0.001). Noteworthy, a reduced mean effective dose was observed when applying UHR-CT (NR-CTA: 1.8 ± 0.3 mSv; UHR-CTA: 1.5 ± 0.5 mSv; p < 0.001). CONCLUSION: Ultra-high-resolution CT-angiography improves image quality in neurovascular imaging allowing the depiction and evaluation of small peripheral cerebral arteries. It may thus improve the detection of pathologies in small cerebrovascular lesions and the resulting diagnosis.

Ultra-High-Resolution CT of the Head and Neck with Deep Learning Reconstruction-Assessment of Image Quality and Radiation Exposure and Intraindividual Comparison with Normal-Resolution CT.

OBJECTIVES: To assess the benefits of ultra-high-resolution CT (UHR-CT) with deep learning-based image reconstruction engine (AiCE) regarding image quality and radiation dose and intraindividually compare it to normal-resolution CT (NR-CT). METHODS: Forty consecutive patients with head and neck UHR-CT with AiCE for diagnosed head and neck malignancies and available prior NR-CT of a different scanner were retrospectively evaluated. Two readers evaluated subjective image quality using a 5-point Likert scale regarding image noise, image sharpness, artifacts, diagnostic acceptability, and assessability of various anatomic regions. For reproducibility, inter-reader agreement was analyzed. Furthermore, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and slope of the gray-value transition between different tissues were calculated. Radiation dose was evaluated by comparing CTDIvol, DLP, and mean effective dose values. RESULTS: UHR-CT with AiCE reconstruction led to significant improvement in subjective (image noise and diagnostic acceptability: p < 0.000; ICC ≥ 0.91) and objective image quality (SNR: p < 0.000; CNR: p < 0.025) at significantly lower radiation doses (NR-CT 2.03 ± 0.14 mSv; UHR-CT 1.45 ± 0.11 mSv; p < 0.0001) compared to NR-CT. CONCLUSIONS: Compared to NR-CT, UHR-CT combined with AiCE provides superior image quality at a markedly lower radiation dose. With improved soft tissue assessment and potentially improved tumor detection, UHR-CT may add further value to the role of CT in the assessment of head and neck pathologies.

Ultrafast Brain MRI Protocol at 1.5 T Using Deep Learning and Multi-shot EPI.

RATIONALE AND OBJECTIVES: To evaluate clinical feasibility and image quality of a comprehensive ultrafast brain MRI protocol with multi-shot echo planar imaging and deep learning-enhanced reconstruction at 1.5T. MATERIALS AND METHODS: Thirty consecutive patients who underwent clinically indicated MRI at a 1.5 T scanner were prospectively included. A conventional MRI (c-MRI) protocol, including T1-, T2-, T2*-, T2-FLAIR, and diffusion-weighted images (DWI)-weighted sequences were acquired. In addition, ultrafast brain imaging with deep learning-enhanced reconstruction and multi-shot EPI (DLe-MRI) was performed. Subjective image quality was evaluated by three readers using a 4-point Likert scale. To assess interrater agreement, Fleiss' kappa (Ï°) was determined. For objective image analysis, relative signal intensity levels for grey matter, white matter, and cerebrospinal fluid were calculated. RESULTS: Time of acquisition (TA) of c-MRI protocols added up to 13:55 minutes, whereas the TA of DLe-MRI-based protocol added up to 3:04 minutes, resulting in a time reduction of 78%. All DLe-MRI acquisitions yielded diagnostic image quality with good absolute values for subjective image quality. C-MRI demonstrated slight advantages for DWI in overall subjective image quality (c-MRI: 3.93 [+/- 0.25] vs DLe-MRI: 3.87 [+/- 0.37], P = .04) and diagnostic confidence (c-MRI: 3.93 [+/- 0.25] vs DLe-MRI: 3.83 [+/- 3.83], P = .01). For most evaluated quality scores, moderate interobserver agreement was found. Objective image evaluation revealed comparable results for both techniques. CONCLUSION: DLe-MRI is feasible and allows for highly accelerated comprehensive brain MRI within 3minutes at 1.5 T with good image quality. This technique may potentially strengthen the role of MRI in neurological emergencies.

Clinical feasibility and validation of the accelerated T2 mapping sequence GRAPPATINI in brain imaging.

Rationale and objectives: To prospectively evaluate feasibility and robustness of an accelerated T2 mapping sequence (GRAPPATINI) in brain imaging and to assess its synthetic T2-weighted images (sT2w) in comparison with a standard T2-weighted sequence (T2 TSE). Material and methods: Volunteers were included to evaluate the robustness and consecutive patients for morphological evaluation. They were scanned on a 3 T MR-scanner. Healthy volunteers underwent GRAPPATINI of the brain three times (day 1: scan/rescan; day 2: follow-up). Patients between the ages of 18 and 85 years who were able to provide written informed consent and who had no MRI contraindications were included. For morphological comparison two radiologists with 5 and 7 years of experience in brain MRI evaluated image quality using a Likert scale (1 being poor, 4 being excellent) in a blinded and randomized fashion. Results: Images were successfully acquired in ten volunteers with a mean age of 25 years (ranging from 22 to 31 years) and 52 patients (23 men/29 women) with a mean age of 55 years (range of 22-83 years). Most brain regions showed repeatable and reproducible T2 values (rescan: CoV 0.75%-2.06%, ICC 69%-92.3%; follow-up: CoV 0.41%-1.59%, ICC 79.4%-95.8%), except for the caudate nucleus (rescan: CoV 7.25%, ICC 66.3%; follow-up: CoV 4.78%, ICC 80.9%). Image quality of sT2w was rated inferior to T2 TSE (median for T2 TSE: 3; sT2w: 1-2), but measurements revealed good interrater reliability of sT2w (lesion counting: ICC 0.85; diameter measure: ICC 0.68 and 0.67). Conclusion: GRAPPATINI is a feasible and robust T2 mapping sequence of the brain on intra- and intersubject level. The resulting sT2w depict brain lesions comparable to T2 TSE despite its inferior image quality.

Single-Energy Metal Artifact Reduction (SEMAR) in Ultra-High-Resolution CT Angiography of Patients with Intracranial Implants.

PURPOSE: To evaluate the effects of single-energy metal artifact reduction (SEMAR) on image quality of ultra-high-resolution CT-angiography (UHR-CTA) with intracranial implants after aneurysm treatment. METHODS: Image quality of standard and SEMAR-reconstructed UHR-CT-angiography images of 54 patients who underwent coiling or clipping was retrospectively evaluated. Image noise (i.e., index for metal-artifact strength) was analyzed in close proximity to and more distally from the metal implant. Frequencies and intensities of metal artifacts were additionally measured and intensity-differences between both reconstructions were compared in different frequencies and distances. Qualitative analysis was performed by two radiologists using a four-point Likert-scale. All measured results from both quantitative and qualitative analysis were then compared between coils and clips. RESULTS: Metal artifact index (MAI) and the intensity of coil-artifacts were significantly lower in SEMAR than in standard CTA in close vicinity to and more distally from the coil-package (p < 0.001, each). MAI and the intensity of clip-artifacts were significantly lower in close vicinity (p = 0.036; p < 0.001, respectively) and more distally from the clip (p = 0.007; p < 0.001, respectively). In patients with coils, SEMAR was significantly superior in all qualitative categories to standard images (p < 0.001), whereas in patients with clips, only artifacts were significantly less (p < 0.05) for SEMAR. CONCLUSION: SEMAR significantly reduces metal artifacts in UHR-CT-angiography images with intracranial implants and improves image quality and diagnostic confidence. SEMAR effects were strongest in patients with coils, whereas the effects were minor in patients with titanium-clips due to the absent of or minimal artifacts.

An NMR-Based Model to Investigate the Metabolic Phenoreversion of COVID-19 Patients throughout a Longitudinal Study.

After SARS-CoV-2 infection, the molecular phenoreversion of the immunological response and its associated metabolic dysregulation are required for a full recovery of the patient. This process is patient-dependent due to the manifold possibilities induced by virus severity, its phylogenic evolution and the vaccination status of the population. We have here investigated the natural history of COVID-19 disease at the molecular level, characterizing the metabolic and immunological phenoreversion over time in large cohorts of hospitalized severe patients (n = 886) and non-hospitalized recovered patients that self-reported having passed the disease (n = 513). Non-hospitalized recovered patients do not show any metabolic fingerprint associated with the disease or immune alterations. Acute patients are characterized by the metabolic and lipidomic dysregulation that accompanies the exacerbated immunological response, resulting in a slow recovery time with a maximum probability of around 62 days. As a manifestation of the heterogeneity in the metabolic phenoreversion, age and severity become factors that modulate their normalization time which, in turn, correlates with changes in the atherogenesis-associated chemokine MCP-1. Our results are consistent with a model where the slow metabolic normalization in acute patients results in enhanced atherosclerotic risk, in line with the recent observation of an elevated number of cardiovascular episodes found in post-COVID-19 cohorts.

Consensus Recommendations Based on Evidence for Abdominal Sepsis in the Pediatric and Adult Population of Colombia / Consenso colombiano de la sepsis abdominal en la poblacion pediatrica y de adultos: Recomendaciones basadas en la evidencia

Abstract Intra-abdominal infections are frequent at all levels of health care, therefore, it is necessary to maintain a high level of clinical suspicion, performing the fastest and most cost-effective measures to confirm the diagnosis and offer a precise and targeted multidisciplinary therapy, this being the only way to have an impact on the morbidity of this infection, reducing mortality and minimizing the complications and costs of health care. Intra-abdominal infections are linked to the appearance and selection of resistant mutants in both bacteria and fungi, becoming currently a major public health problem. Increasing bacterial resistance when associated with a greater possibility of difficulties in antimicrobial treatment increases mortality. This evidence-based consensus brings together the recommendations for the diagnosis and treatment of intra-abdominal infections in the pediatric and adult population. With strict monitoring of bacterial resistance and stimulating the control of the risk factors that have the greatest impact on the appearance of this phenomenon, this consensus is intended to be a practical guide that is easy to implement, and with periodic updates it will favor and facilitate multidisciplinary and the adequacy of the therapeutic management of intra-abdominal infections.

Resumen Las infecciones intrabdominales son frecuentes en todos los niveles de atención en salud, por ende, es necesario mantener un alto nivel de sospecha clínica, realizando las medidas más rápidas y costoefectivas para confirmar el diagnóstico y así ofrecer de una forma precisa y dirigida la terapéutica multidisciplinaria, siendo esta la única manera de tener impacto en la morbilidad de esta infección, disminuyendo la mortalidad y minimizando las complicaciones y los costos de la atención en salud. Las infecciones intrabdominales se encuentran ligadas a la aparición y selección de las mutantes resistentes tanto en las bacterias como en los hongos, convirtiéndose en la actualidad en una gran problemática en la salud pública. La creciente resistencia bacteriana al asociarse a mayor posibilidad de dificultades en el tratamiento antimicrobiano incrementa la mortalidad. Este consenso basado en la evidencia, reúne las recomendaciones en el diagnóstico y en el tratamiento de las infecciones intrabdominales en la población pediátrica y de adultos. Con un estricto seguimiento de la resistencia bacteriana y estimulando el control de los factores de riesgo que tienen mas impacto en la aparición de este fenómeno, este consenso pretende ser una practica guía de fácil implementación, y con periódicas actualizaciones favorecerá y facilitará el manejo multidisciplinario y la adecuación del manejo terapéutico de las infecciones intrabdominales.

Feasibility of Ultra-High Resolution Supra-Aortic CT Angiography: An Assessment of Diagnostic Image Quality and Radiation Dose.

(1) Background: To evaluate diagnostic image quality and radiation exposure of ultra-high resolution cerebral Computed-Tomography (CT) angiography (CTA) obtained on an ultra-high resolution computed tomography scanner (UHR-CT). (2) Methods: Fifty consecutive patients with UHR-CTA were enrolled. Image reconstruction was processed with a 1024 × 1024 matrix and a slice thickness of 0.25 mm. Quantitative analyses comprising CT values, contrast-noise ratio (CNR) and signal-to-noise ratio (SNR) were performed. Subjective assessment of image quality, vessel contrast, noise, artefacts and delineation of different sized vessels were assessed by two readers on a 4-point scale. Radiation exposure was determined. (3) Results: Hounsfield values (ACI: 461.8 ± 16.8 HU; MCA: 406.1 ± 24.2 HU; BA: 412.2 ± 22.3 HU), SNR (ACI: 35.4 ± 13.1; MCA: 20.8 ± 12.4; BA: 23.7 ± 12.9) and CNR (ACI: 48.7 ± 21; MCA: 63.9 ± 26.9; BA: 48.1 ± 21.4) were remarkably high in all segments. Subjective analysis by two raters (fair agreement, k = 0.26) indicated excellent image qualities (image quality = 4; contrast = 4; noise = 3; artefacts = 4).Our analysis revealed a notably high traceability of the cerebral perforators (3 Points). Radiation exposure was at moderate dose levels (effective dose = 2.5 ± 0.6mSv). (4) Conclusions: UHR-CTA generates highly valuable image qualities that allow the depiction of vessels including cerebral perforators at acceptable dose levels. The UHR-CTA may therefore enhance the detection of small cerebral pathologies and may improve interpretability, especially in settings where high image qualities are crucial for the diagnostic accuracy.

Clinical course and short-term mortality of cirrhotic patients with infections other than spontaneous bacterial peritonitis.

BACKGROUND & AIMS: Clinical course and risk factors of death in non-spontaneous bacterial peritonitis (SBP) infections are poorly known. We assessed the prevalence of acute kidney injury (AKI) and type-1 hepatorenal syndrome (HRS), hospital, 30-day and 90-day mortality and risk factors of death in 441 decompensated patients. METHODS: Analysis of 615 non-SBP infections (161 urinary infections (UTI), 95 cellulitis, 92 suspected infections, 92 bacteraemias, 84 pneumonias, 21 bronchitis, 18 cholangitis, 15 spontaneous empyema, 13 secondary peritonitis, 24 other). RESULTS: Ninety-six percent of infections solved. AKI and type-1 HRS were developed in 37% and 9% of infections respectively. Overall hospital, 30-day and 90-day mortality rates were 11%, 12% and 18% respectively. Clinical course and mortality differed markedly across infections. Endocarditis, osteoarticular infections, pneumonia, spontaneous bacteraemia, cholangitis, secondary peritonitis and UTI showed higher rates of AKI. Prevalence of type-1 HRS was not significantly different among infections. Endocarditis, secondary peritonitis, pneumonia and bacteraemia showed lower rates of renal impairment resolution and higher hospital mortality associated with AKI (42% vs 12%, P<.0001) or type-1 HRS (71% vs 27%, P=.003) than the rest of infections. Age (HR: 1.04), serum sodium (HR: 0.91), serum bilirubin (HR: 1.06), INR (HR: 1.91), hepatic encephalopathy (HR: 2.44), ascites (HR: 3.06) and multidrug-resistant isolation (HR: 2.27) at infection diagnosis were independent predictors of death during hospitalization. CONCLUSIONS: Non-SBP infections constitute a heterogeneous group regarding clinical course and prognosis. Endocarditis, secondary peritonitis, pneumonia and bacteraemia show worse prognosis. The combination of data of liver and renal dysfunction and of the type of infection allows the identification of patients with poor prognosis.

Chlamydia trachomatis in the conjunctiva of children living in three rural areas in Mexico.

OBJECTIVES: Chlamydia trachomatis infections, in the context of extreme poverty, may trigger trachoma. Because the levels of C. trachomatis eye infections in Mexico are unknown, this study sought to determine if C. trachomatis was present in the conjunctiva of children living in three poor, rural areas of the country. METHODS: Clinical diagnosis of conjunctival follicles in children was conducted during the 2004 visual acuity assessment campaigns in rural areas of the states of Chiapas, Oaxaca, and Zacatecas. C. trachomatis detection was carried out by sampling the children with follicles and examining the specimens after Giemsa or microimmunofluorescence (MIF) staining. RESULTS: A total of 941 children from 6 to 12 years of age were examined in 2004. Of the 484 in Chiapas, 30% were found to have follicles; of the 181 in Zacatecas, 22%; and of the 276 in Oaxaca, 42%. C. trachomatis was detected at levels ranging between 2% and 5%; positive by Giemsa in 4.5% of the children with follicles, and by MIF in 15.5%. CONCLUSIONS: Considering that the chlamydiae sampling procedures and detection methods used in this study were not the most sensitive, the results underestimate the chlamydial eye infections and represent a conservative assessment of a potential risk for preventable visual impairment. Because C. trachomatis was detected here at levels similar to those reported for low-endemic trachoma areas, health authorities should be prepared to implement appropriate measures should it be confirmed that the visual health of Mexico's children is at risk.

Chlamydia trachomatis in the conjunctiva of children living in three rural areas in Mexico

OBJECTIVES: Chlamydia trachomatis infections, in the context of extreme poverty, may trigger trachoma. Because the levels of C. trachomatis eye infections in Mexico are unknown, this study sought to determine if C. trachomatis was present in the conjunctiva of children living in three poor, rural areas of the country. METHODS: Clinical diagnosis of conjunctival follicles in children was conducted during the 2004 visual acuity assessment campaigns in rural areas of the states of Chiapas, Oaxaca, and Zacatecas. C. trachomatis detection was carried out by sampling the children with follicles and examining the specimens after Giemsa or microimmunofluorescence (MIF) staining. RESULTS: A total of 941 children from 6 to 12 years of age were examined in 2004. Of the 484 in Chiapas, 30 percent were found to have follicles; of the 181 in Zacatecas, 22 percent; and of the 276 in Oaxaca, 42 percent. C. trachomatis was detected at levels ranging between 2 percent and 5 percent; positive by Giemsa in 4.5 percent of the children with follicles, and by MIF in 15.5 percent. CONCLUSIONS: Considering that the chlamydiae sampling procedures and detection methods used in this study were not the most sensitive, the results underestimate the chlamydial eye infections and represent a conservative assessment of a potential risk for preventable visual impairment. Because C. trachomatis was detected here at levels similar to those reported for low-endemic trachoma areas, health authorities should be prepared to implement appropriate measures should it be confirmed that the visual health of MexicoÆs children is at risk.

OBJETIVOS: En un contexto de pobreza extrema, la infección por Chlamydia trachomatis puede desencadenar el tracoma. Debido a que se desconocen los niveles de infección ocular con C. trachomatis en México, el objetivo de este estudio fue determinar la presencia de C. trachomatis en la conjuntiva de niños de tres zonas rurales pobres de México. MÉTODOS:El diagnóstico clínico de folículos conjuntivales en los niños se llevó a cabo durante la campaña de evaluación de la agudeza visual en áreas rurales de los estados de Chiapas, Oaxaca y Zacatecas en 2004. Para la detección de C. trachomatis se tomaron muestras de los niños con folículos y se analizaron mediante la tinción de Giemsa o microinmunofluorescencia (MIF). RESULTADOS: En total se examinaron 941 niños de 6 a 12 años de edad en 2004. Se observaron folículos en 30 por ciento de los 484 niños de Chiapas, en 22 por ciento de los 181 de Zacatecas y en 42 por ciento de los 276 niños de Oaxaca. Se detectó C. trachomatis en niveles entre 2 por ciento y 5 por ciento; de los niños con folículos, 4,5 por ciento resultaron positivos por Giemsa y 15,5 por ciento por MIF. CONCLUSIONES: Estos resultados subestiman el nivel de infección ocular por clamidia, ya que los procedimientos de muestreo y los métodos de detección de clamidia empleados en este estudio no eran los más sensibles, por lo que representan una valoración conservadora del riesgo de trastornos visuales prevenibles. Como los niveles de C. trachomatis encontrados son similares a los informados para áreas de baja endemia de tracoma, las autoridades de salud deben estar listas para implementar medidas apropiadas si se confirmaran los riesgos para la salud visual de los niños mexicanos.

El tiempo de los estudiantes de medicina en las rotaciones clínicas y el sistema de créditos / Medical Student's Use of Time during Clinical Clerkships and the Credits Based System

Introducción: La formación en ciencias clínicas del pregrado de medicina se fundamenta en rotaciones clínicas. Para implementar el sistema de créditos es necesario conocer cómo se llevan a cabo estas experiencias. Objetivo: Describir cómo los estudiantes utilizan el tiempo durante las rotaciones clínicas, el valor académico y el grado de disfrute que le asignan a las actividades. Metodología: Estudio descriptivo con una muestra aleatoria estratificada de cien estudiantes de los semestres clínicos. Se recolectó información sobre el tiempo empleado durante una semana, el valor educativo y el grado de disfrute de las actividades de las rotaciones clínicas. Los datos fueron analizados en Excel® 98 y SPSS. Resultados: Las actividades de un día ocuparon en promedio 10.8 h, con 7.3 h (69%) dedicadas a actividades académicas. La actividad asistencial con docente representó el mayor porcentaje de utilización del tiempo (15.4%). Durante una semana, el 56% (28 h) del tiempo efectivo estuvo dedicado al trabajo asistencial y 22.4 h (44.5%) al trabajo independiente en el sitio de práctica. El tiempo dedicado al aprendizaje en la rotación clínica corresponde a 19 créditos para un semestre de 18 semanas. Las actividades calificadas con mayor valor educativo fueron el estudio independiente por fuera de la institución (4.6) y las actividades académicas con el docente (4.5). Las calificadas como de mayor disfrute fueron las extracurriculares y la docencia formal. Conclusiones: Los estudiantes tienen mayor tiempo de contacto con los pacientes que el reportado en la literatura. El trabajo presencial de nuestros estudiantes es mayor al reportado en estudios similares.

Introduction: Comprehensive undergraduate education in clinical sciences is grounded on activities developed during clerkships. To implement the credits system we must know how these experiences take place. Objectives: to describe how students spend time in clerkships, how they assess the educative value of activities and the enjoyment it provides. Method: We distributed a form to a random clustered sample of a 100 students coursing clinical sciences, designed to record the time spent, and to assess the educative value and the grade of enjoyment of the activities in clerkship during a week. Data were registered and analyzed on Excel® 98 and SPSS. Results: mean time spent by students in clerkship activities on a day were 10.8 hours. Of those, 7.3 hours (69%) were spent in formal education activities. Patient care activities with teachers occupied the major proportion of time (15.4%). Of the teaching and learning activities in a week, 28 hours (56%) were spent in patient care activities and 22.4 hours (44.5%) were used in independent academic work. The time spent in teaching and learning activities correspond to 19 credits of a semester of 18 weeks. The activities assessed as having the major educational value were homework activities (4.6) and formal education activities (4.5). The graded as most enjoyable were extracurricular activities, formal educational activities and independent academic work. Conclusion: our students spend more time in activities with patients than the reported in literature. The attending workload of our students is greater than the one reported in similar studies.