How doctors generate diagnostic hypotheses: a study of radiological diagnosis with functional magnetic resonance imaging.

BACKGROUND: In medical practice, diagnostic hypotheses are often made by physicians in the first moments of contact with patients; sometimes even before they report their symptoms. We propose that generation of diagnostic hypotheses in this context is the result of cognitive processes subserved by brain mechanisms that are similar to those involved in naming objects or concepts in everyday life. METHODOLOGY AND PRINCIPAL FINDINGS: To test this proposal we developed an experimental paradigm with functional magnetic resonance imaging (fMRI) using radiological diagnosis as a model. Twenty-five radiologists diagnosed lesions in chest X-ray images and named non-medical targets (animals) embedded in chest X-ray images while being scanned in a fMRI session. Images were presented for 1.5 seconds; response times (RTs) and the ensuing cortical activations were assessed. The mean response time for diagnosing lesions was 1.33 (SD ±0.14) seconds and 1.23 (SD ±0.13) seconds for naming animals. 72% of the radiologists reported cogitating differential diagnoses during trials (3.5 seconds). The overall pattern of cortical activations was remarkably similar for both types of targets. However, within the neural systems shared by both stimuli, activation was significantly greater in left inferior frontal sulcus and posterior cingulate cortex for lesions relative to animals. CONCLUSIONS: Generation of diagnostic hypotheses and differential diagnoses made through the immediate visual recognition of clinical signs can be a fast and automatic process. The co-localization of significant brain activation for lesions and animals suggests that generating diagnostic hypotheses for lesions and naming animals are served by the same neuronal systems. Nevertheless, diagnosing lesions was cognitively more demanding and associated with more activation in higher order cortical areas. These results support the hypothesis that medical diagnoses based on prompt visual recognition of clinical signs and naming in everyday life are supported by similar brain systems.

Tomografia de coronárias: indicações clínicas e perspectivas futuras / Coronary CT: clinical indications and future directions

A tomografia computadorizada de multidetectores (TCMD) iniciou sua aplicação dentro da cardiologia com a quantificação de cálcio das placas coronarianas, no estudo sem contraste, por meio do escore de cálcio, mostrando um importante preditor independente de futuros eventos cardíacos. O exame com contraste endovenoso, a angiotomografia de coronárias, surgiu posteriormente como um método não invasivo para avaliação da anatomia e da doença obstrutiva coronariana, caracterizando o grau de estenose e também a presença da placa aterosclerótica não calcificada, avaliando não somente o lúmen, mas também a parede do vaso. Com o advento de novos aparelhos com mais detectores e maior resolução temporal, tem ocorrido uma redução da dose de radiação e a possibilidade de novas aplicações.

Real-time three-dimensional echocardiographic left ventricular systolic assessment: side-by-side comparison with 64-slice multi-detector cardiac computed tomography.

AIMS: To investigate by real-time 3D echocardiography (RT3DE) and cardiac computed tomography (CCT) the analysis of left ventricle ejection fraction (LVEF) and volumes. METHODS AND RESULTS: A total of 67 patients (37 males, 55 +/- 11 years) were studied prospectively by RT3DE and by 64-slice CCT. RT3DE data: LVEF ranged from 30 to 78.6% (63.1 +/- 7.33); left ventricular end-diastolic volume (LVEDV) from 44.1 to 210 (104.9 +/- 29.7) mL; left ventricular end-systolic volume (LVESV) from 11.4 to 149 ( 38.9 +/- 19.3) mL. CCT data: LVEF ranged from 28 to 86% (66 +/- 8.4); LVEDV from 51 to 212 (110.3 +/- 31.2) mL; LVESV from 7 to 152 (38.2 +/- 19.2) mL. Correlations relative to RT3DE and CCT were: LVEF (r: 0.79, P < 0.0001); LVEDV (r: 0.82, P < 0.0001); and LVESV (r: 0.91, P < 0.0001). CONCLUSION: It was observed adequate correlation between RT3DE and CCT ventricular systolic function and geometry assessment.

Left ventricular ejection fraction and volumes as measured by 3d echocardiography and ultrafast computed tomography.

BACKGROUND: Real-time three-dimensional echocardiography (RT-3D-Echo) and ultrafast computed tomography (CT) are two novel methods for the analysis of LV ejection fraction and volumes. OBJECTIVE: To compare LVEF and volume measurements as obtained using RT-3D-Echo and ultrafast CT. METHODS: Thirty nine consecutive patients (27 men, mean age of 57+/-12 years) were studied using RT-3D-Echo and 64-slice ultrafast CT. LVEF and LV volumes were analyzed. STATISTICAL ANALYSIS: coefficient of correlation (r: Pearson), Bland-Altman analysis, linear regression analysis, 95% CI, p<0.05. RESULTS: RT-3D-Echo measurements: LVEF ranged from 56.1 to 78.6 (65.5+/-5.58)%; end-diastolic volume ranged from 49.6 to 178.2 (87+/-27.8) ml; end-systolic volume ranged from 11.4 to 78 (33.1+/-13.6) ml. CT scan measurements: LVEF ranged from 53 to 86% (67.8+/-7.78); end-diastolic volume ranged from 51 to 186 (106.5+/-30.3) ml; end-systolic volume ranged from 7 to 72 (35.5+/-13.4)ml. Correlations between RT-3D-Echo and CT were: LVEF (r: 0.7888, p<0.0001, 95% CI 0.6301 to 0.8843); end-diastolic volume (r: 0.7695, p<0.0001, 95% CI 0.5995 to 0.8730); end-systolic volume (r: 0.8119, p<0.0001, 95% CI 0.6673 to 0.8975). CONCLUSION: Good correlation between LVEF and ventricular volume parameters as measured by RT-3D-Echo and 64-slice ultrafast CT was found in the present case series.

Fração de ejeção e volumes do ventrículo esquerdo medidos com eco 3D e com tomografia ultra-rápida / Fracción de eyección y volúmenes del ventrículo izquierdo medidos con eco- 3DTR y con tomografía ultrarrápida / Left ventricular ejection fraction and volumes as measured by 3d echocardiography and ultrafast computed tomography

FUNDAMENTO: O ecocardiograma tridimensional em tempo real (ECO 3D) e a tomografia computadorizada ultra-rápida (CT) são dois novos métodos de análise da fração de ejeção e dos volumes do VE. OBJETIVO: Comparar as medidas da FEVE e dos volumes do VE aferidos pelo ECO 3D e pela CT ultra-rápida. MÉTODOS: Foram estudados pelo ECO 3D e pela CT ultra-rápida de 64 cortes, 39 pacientes consecutivos (27 homens, média etária de 57±12 anos). Foram analisados: FEVE e volumes do VE. Análise estatística: coeficiente de correlação (r: Pearson), teste de Bland & Altman, teste de regressão linear, 95 por cento IC, p<0,05. RESULTADOS: Medidas do ECO 3D: a FEVE variou de 56,1 a 78,6 (65,5±5,58) por cento; volume diastólico final variou de 49,6 a 178,2 (87±27,8)ml; volume sistólico final variou de 11,4 a 78 (33,1±13,6)ml. Medidas da CT: a FEVE variou de 53 a 86 (67,8±7,78) por cento; volume diastólico final variou de 51 a 186 (106,5±30,3) ml; volume sistólico final variou de 7 a 72 (35,5±13,4)ml. As correlações entre ECO 3D e CT foram: FEVE (r: 0,7888, p<0,0001, 95 por cento IC 0,6301 a 0,8843); volume diastólico final (r: 0,7695, p<0,0001, 95 por cento IC 0,5995 a 0,8730); volume sistólico final (r: 0,8119, p<0,0001, 95 por cento IC 0,6673 a 0,8975). CONCLUSÃO: Nesta série, foi observada boa correlação entre as medidas da FEVE e entre os volumes ventriculares aferidos pelo ECO3D e pela CT ultra-rápida de 64 cortes.

BACKGROUND: Real-time three-dimensional echocargiography (RT-3D-Echo) and ultrafast computed tomography (CT) are two novel methods for the analysis of LV ejection fraction and volumes. OBJECTIVE: To compare LVEF and volume measurements as obtained using RT-3D-Echo and ultrafast CT. METHODS: Thirty nine consecutive patients (27 men, mean age of 57±12 years) were studied using RT-3D-Echo and 64-slice ultrafast CT. LVEF and LV volumes were analyzed. Statistical analysis: coefficient of correlation (r: Pearson), Bland-Altman analysis, linear regression analysis, 95 percent CI, p<0.05. RESULTS: RT-3D-Echo measurements: LVEF ranged from 56.1 to 78.6 (65.5±5.58) percent; end-diastolic volume ranged from 49.6 to 178.2 (87±27.8) ml; end-systolic volume ranged from 11.4 to 78 (33.1±13.6) ml. CT scan measurements: LVEF ranged from 53 to 86 percent (67.8±7.78); end-diastolic volume ranged from 51 to 186 (106.5±30.3) ml; end-systolic volume ranged from 7 to 72 (35.5±13.4)ml. Correlations between RT-3D-Echo and CT were: LVEF (r: 0.7888, p<0.0001, 95 percent CI 0.6301 to 0.8843); end-diastolic volume (r: 0.7695, p<0.0001, 95 percent CI 0.5995 to 0.8730); end-systolic volume (r: 0.8119, p<0.0001, 95 percent CI 0.6673 to 0.8975). CONCLUSION: Good correlation between LVEF and ventricular volume parameters as measured by RT-3D-Echo and 64-slice ultrafast CT was found in the present case series.

FUNDAMENTO: La ecocardiografía tridimensional en tiempo real (Eco-3DTR) y la tomografía computarizada ultrarrápida (TC ultrarrápida) son dos nuevos métodos de análisis de la fracción de eyección (FE) y de los volúmenes del ventrículo izquierdo (VI). OBJETIVO: Comparar las mediciones de la fracción de eyección del ventrículo izquierdo (FEVI) y de los volúmenes del VI apurados por la Eco-3DTR y por la TC ultrarrápida. MÉTODOS: Se estudiaron, mediante la Eco-3DTR y la TC ultrarrápida de 64 cortes, a 39 pacientes consecutivos (27 varones, promedio de edad de 57±12 años). Se analizaron: FEVI y volúmenes del VI. Análisis estadístico: coeficiente de correlación (r: Pearson), prueba de Bland & Altman, prueba de regresión lineal, 95 por ciento IC, p<0,05. RESULTADOS: Valores de la Eco-3DTR: variación de la FEVI de 56,1 a 78,6 (65,5±5,58) por ciento; variación del volumen diastólico final de 49,6 a 178,2 (87±27,8)mL; variación del volumen sistólico final de 11,4 a 78 (33,1±13,6)mL. Valores de la TC ultrarrápida: variación de la FEVI de 53 a 86 (67,8±7,78) por ciento; variación del volumen diastólico final de 51 a 186 (106,5±30,3) mL; variación del volumen sistólico final de 7 a 72 (35,5±13,4) mL. Las correlaciones entre la Eco-3DTR y la TC ultrarrápida fueron: FEVI (r: 0,7888, p<0,0001, 95 por ciento IC 0,6301 a 0,8843); volumen diastólico final (r: 0,7695, p<0,0001, 95 por ciento IC 0,5995 a 0,8730); volumen sistólico final (r: 0,8119, p<0,0001, 95 por ciento IC 0,6673 a 0,8975). CONCLUSIÓN: En esta serie, se observó una buena correlación entre las mediciones de la FEVI y entre los volúmenes ventriculares apurados por la Eco-3DTR y por la TC ultrarrápida de 64 cortes.

Comparação entre a aferição da fração de ejeção e dos volumes do ventrículo esquerdo, medidos com ecocardiografia tridimensional em tempo real e com tomografia computadorizada ultra-rápida / Real-time three-dimensional echocardiographic left ventricular ejection fraction and volumes asessment: comparison with cardiac computed tomography

Fundamento e objetivo: O ecocardiograma tridimensional (ECO 3D) e a tomografia computadorizada ultra-rápida (CT) constituem 2 novos métodos de análise da fração de ejeção e dos volumes do ventrículo esquerdo (VE). Existem poucos estudos dirigidos à comparação da análise da fração de ejeção do VE aferidos por ambos os métodos. O objetivo deste estudo foi comparar as medidas da FEVE e dos volumes do VE ECO 3D em tempo real e pela CT ultra rápida. Método: Foram estudados pelo ECO 3D e pela CT ultra rápida de 64 cortes, 41 pacientes (29 homens, média etária de 58 + - 111 anos). Foram analisados com ambas as técnicas: FEVE, volumes sistólico final e diastólico final do VE. Os parâmetros aferidos com o ECO3D e com a CT foram comparados com o emprego do coeficiente de determinação (r:Pearson), do teste de Bland & Altman e do teste de regressão linear, 95 por cento IC, p<0,05. Resultados: Medidas do ECO 3D: a FEVE variou de 56,7 a 78,9 (65,3 + - 5,7) por cento; volume diastólico final variou de 49,6 a 178,2 (88+ - 27,5) mL; volume sistólico final variou de 11,4 a 78 (33,9 + - 13,7) mL. Medidas da CT: a FEVE variou de 7 a 72 (35,1 + - 13,8) mL. As correlações entre ECO 3D e CT foram: FEVE (r: 0,7877, p>0,0001, 95 por cento IC 0,6327 a 0,8853); volume diastólico final (r:0,7671, p< 0,0001, 95 por cento IC 0,5974 a 0,8745); volume sistólico final (r: 0,8121, p< 0,0001, 95 por cento IC 0,6659 a 0,8957). Conclusão: Foi evidenciada boa correlação entre as medidas da FEVE e entre os volumes ventriculares aferidos pelo ECO3D em tempo real e pela CT ultra rápida de 64 cortes.