Design, construction, and evaluation of a dynamic MR compatible cardiac left ventricle model.

PURPOSE: Development of magnetic resonance (MR) sequences is important to answer clinical questions and to overcome current limitations. To meet the challenges of cardiac MR, dynamic and reproducible testing conditions are required. We aimed at developing a dynamic MR-compatible cardiac left ventricle model that imitates myocardial tissue properties and simulates dynamic motion. METHODS: A dynamic left ventricle silicone model was designed to match myocardial T(1) and T(2) relaxation times. Silicone mixtures were explored to replicate T(2) values of myocardial edema. A controllable piston pump was constructed to produce pulsatile flow paradigms. They were validated against flow sensors and MR data, including SSFP-based and phase-contrast-based sequences. A dedicated software interface was developed for the control. RESULTS: Model dimensions represented cardiac left ventricle dimensions of healthy men. The range of end diastolic volumes was 85-175 ml, depending on the driven stroke volume. Stroke volume quantification for flow paradigms of 30∕60∕90∕120 ml resulted in 29.2∕57.6∕88.8∕118.4 ml by MR volumetry, 29.6∕59.9∕89.4∕119.0 ml by phase contrast measurements, and 29.9∕60.4∕91.1∕120.9 ml by flow meter revealing consistency. The system accurately replicated physiological and pathophysiological flow paradigms. The silicon model exhibited T(1) of 1002 ± 8 ms, T(2) of 58 ± 1 ms. Signal intensities (a.u.) of the ventricle model were 128 ± 23 for FGRE (vs 138 ± 17 in vivo) and 1156 ± 37 for b-SSFP (vs 991 ± 96 in vivo). T(2) of 75 ± 2 ms was achieved for the myocardial pathology. CONCLUSIONS: We developed a controllable left ventricle model resembling MR signal characteristics of human myocardium, including pathological conditions, and allowing for the replication of contraction and flow paradigms.

Most common histopathological patterns of the Minas Gerais Association of the Centers of Nephrology.

INTRODUCTION: We analyzed the distribution and frequency of glomerular diseases in patients biopsied between 1992 and 2016 in centers that make up the AMICEN (Minas Gerais Association of Nephrology Centers). METHODS: We analyzed the biopsy reports of patients from 9 AMICEN nephrology centers. We took note of their age, gender, ultrasound use, post-biopsy resting time, whether the kidney was native or a graft, number of glomeruli and indication for the biopsy. The kidney biopsy findings were broken down into four categories: glomerular and non-glomerular diseases, normal kidneys and insufficient material for analysis. Those patients diagnosed with glomerular diseases were further divided into having primary or secondary glomerular diseases. RESULTS: We obtained 582 biopsy reports. The median age was 38 years (1 to 85). The number of glomeruli varied between 0 and 70 (median = 13.0). In total, 97.8% of the biopsies were ultrasound guided. The main indication was nephrotic syndrome (36.9%), followed by hematuria-proteinuria association (16.2%). Primary glomerular diseases proved to be the most frequent (75.3%), followed by secondary diseases (24.7%). Among the primary glomerular diseases, FSGS was found at a higher frequency (28.8%), while among the secondary diseases, SLE was the most prevalent (42.4%). Regarding prevalence findings, those for both primary and secondary diseases were similar to those found in the large Brazilian registries published thus far. CONCLUSION: Glomerular disease registries are an important tool to identify the prevalence of such disease in regions of interest and can serve as an instrument to guide public policy decisions concerning the prevention of terminal kidney diseases.

Most common histopathological patterns of the Minas Gerais Association of the Centers of Nephrology

SUMMARY INTRODUCTION: We analyzed the distribution and frequency of glomerular diseases in patients biopsied between 1992 and 2016 in centers that make up the AMICEN (Minas Gerais Association of Nephrology Centers). METHODS: We analyzed the biopsy reports of patients from 9 AMICEN nephrology centers. We took note of their age, gender, ultrasound use, post-biopsy resting time, whether the kidney was native or a graft, number of glomeruli and indication for the biopsy. The kidney biopsy findings were broken down into four categories: glomerular and non-glomerular diseases, normal kidneys and insufficient material for analysis. Those patients diagnosed with glomerular diseases were further divided into having primary or secondary glomerular diseases. RESULTS: We obtained 582 biopsy reports. The median age was 38 years (1 to 85). The number of glomeruli varied between 0 and 70 (median = 13.0). In total, 97.8% of the biopsies were ultrasound guided. The main indication was nephrotic syndrome (36.9%), followed by hematuria-proteinuria association (16.2%). Primary glomerular diseases proved to be the most frequent (75.3%), followed by secondary diseases (24.7%). Among the primary glomerular diseases, FSGS was found at a higher frequency (28.8%), while among the secondary diseases, SLE was the most prevalent (42.4%). Regarding prevalence findings, those for both primary and secondary diseases were similar to those found in the large Brazilian registries published thus far. CONCLUSION: Glomerular disease registries are an important tool to identify the prevalence of such disease in regions of interest and can serve as an instrument to guide public policy decisions concerning the prevention of terminal kidney diseases.

RESUMO INTRODUÇÃO: Analisamos a distribuição e frequência de doenças glomerulares de pacientes biopsiados entre 1992 e 2016 em centros que compõem a Amicen (Associação de Minas Gerais de Nefrologia). MÉTODOS: Analisamos os relatórios de biópsia de pacientes de nove centros de nefrologia da Amicen. Observamos idade, gênero, uso de ultrassom, tempo de descanso pós-biópsia, se o rim era nativo ou um enxerto, número de glomérulos e indicação para a biópsia. Os achados da biópsia do rim foram divididos em quatro categorias: doenças glomerulares e não glomerulares, rins normais e material insuficiente para análise. Os pacientes diagnosticados com doenças glomerulares foram ainda divididos em doenças glomerulares primárias ou secundárias. RESULTADOS: Obtivemos 582 relatórios de biópsia. A idade mediana foi de 38 anos (1 a 85). O número de glomérulos variou entre zero e 70 (mediana = 13,0). No total, 97,8% das biópsias foram guiadas por ultrassom. A principal indicação foi síndrome nefrótica (36,9%), seguida de associação hematúria-proteinúria (16,2%). As doenças glomerulares primárias revelaram-se as mais frequentes (75,3%), seguidas de doenças secundárias (24,7%). Entre as doenças glomerulares primárias, o FSGS foi encontrado em maior frequência (28,8%), enquanto nas doenças secundárias, o lúpus eritematoso sistêmico foi o mais prevalente (42,4%). Quanto aos achados de prevalência, aqueles para doenças primárias e secundárias foram semelhantes aos encontrados nos grandes registros brasileiros publicados até o momento. CONCLUSÃO: Os registros de doenças glomerulares são uma ferramenta importante para identificar a prevalência dessas doenças em regiões de interesse e pode servir como um instrumento para orientar decisões de políticas públicas relativas à prevenção de doenças renais terminais.