Tomografía computarizada de pitch alto en estudios de triple descarte: dosis de radiación y calidad de la imagen comparada con la de la tomografía computarizada multidetector / High pitch CT in triple rule-out studies: radiation dose and image quality compared to multidetector CT

Objetivo. Comparar la calidad de imagen y dosis de radiación de la TC de doble fuente (128-TCDF) con pitch alto y la adquisición retrospectiva con TC de 64 filas de detectores (64-TCMD) en estudios de triple descarte. Material y métodos. Estudiamos retrospectivamente 60 pacientes con dolor torácico agudo: 30 con una adquisición ECG-retrospectiva con 64-TCMD y 30 con 128-TCDF y pitch alto. Analizamos cuantitativamente la calidad de la imagen calculando la densidad vascular (DV), densidad muscular (DM), ruido y cocientes densidad vascular/ruido (CDVR) y contraste/ruido (CCR). Valoramos cualitativamente los artefactos en la vena cava, aorta y coronarias. Calculamos la dosis de radiación efectiva estimada (DRE) con el producto dosis-longitud. Resultados. No hubo diferencias significativas en la DV. Con 128-TCDF los CDVR y CCR fueron mayores en la aorta (CDVR: 28,9 ± 11,7 y 20 ± 5,5; CCR: 24,4 ± 10,9 y 16,8 ± 5,4; p < 0,01), arterias pulmonares (CDVR: 25,5 ± 10 y 20,6 ± 6,5; CCR: 24,5 ± 5,4 y 17,4 ± 6,4; p < 0,01) y coronarias (CDVR: 25,9 ± 8,2 y 18,9 ± 4,9; CCR: 24,9 ± 8,2 y 15,6 ± 4,6; p < 0,01). Los artefactos coronarios (3 y 34 segmentos no diagnósticos p < 0,001) y la DRE (13,77 ± 4 y 2,77 ± 0,6 mSv; p < 0,001) fueron menores con 128-TCDF. Conclusión. El pitch alto en el triple descarte disminuye la dosis de radiación y mejora la calidad de la imagen con respecto a la adquisición retrospectiva con 64-TCMD (AU)

Objective. To compare the image quality and radiation dose from high pitch dual source CT (128-DSCT) versus those from retrospective acquisition with 64-row multidetector CT (64-MDCT) in triple rule-out studies. Material and methods. We retrospectively studied 60 patients with acute chest pain: 30 with a retrospective EKG acquisition with 64-MDCT and 30 with high pitch 128-DSCT. We quantitatively analyzed the image quality by calculating the vascular density, muscular density (DM), noise, vascular density/noise ratio (VDNR), and contrast/noise ratio (CNR). We qualitatively evaluated the artifacts in the vena cava, aorta, and coronary arteries. We estimated the effective dose (ED) of radiation by means of the dose-length product. Results. There were no significant differences between 128-DSCT and 64-MDCT in the vascular density. The VDNR and CNR were higher on 128-DSCT than on 64-MDCT in the aorta (VDNR: 28.9 ± 11.7 vs. 20 ± 5.5; CNR: 24.4 ± 10.9 vs. 16.8 ± 5.4; P < .01), in the pulmonary arteries (VDNR: 25.5 ± 10 vs. 20.6 ± 6.5; CNR: 24.5 ± 5.4 vs. 17.4 ± 6.4; P < .01), and in the coronary arteries (VDNR: 25.9 ± 8.2 vs. 18.9 ± 4.9; CNR: 24.9 ± 8.2 vs. 15.6 ± 4.6; P < .01). There were fewer artifacts in the coronary arteries on 128-DSCT than on 64-MDCT (3 vs. 34 nondiagnostic segments; P < .001), and the ED in 128-DSCT was lower than in 64-MDCT (13.77 ± 4 vs. 2.77 ± 0.6 mSv; P < .001). Conclusion. In triple rule-out studies, high pitch 128-DSCT delivers a lower dose of radiation and provides better image quality than retrospective acquisition with 64-MDCT (AU)

High pitch CT in triple rule-out studies: Radiation dose and image quality compared to multidetector CT.

OBJECTIVE: To compare the image quality and radiation dose from high pitch dual source CT (128-DSCT) versus those from retrospective acquisition with 64-row multidetector CT (64-MDCT) in triple rule-out studies. MATERIAL AND METHODS: We retrospectively studied 60 patients with acute chest pain: 30 with a retrospective EKG acquisition with 64-MDCT and 30 with high pitch 128-DSCT. We quantitatively analyzed the image quality by calculating the vascular density, muscular density (DM), noise, vascular density/noise ratio (VDNR), and contrast/noise ratio (CNR). We qualitatively evaluated the artifacts in the vena cava, aorta, and coronary arteries. We estimated the effective dose (ED) of radiation by means of the dose-length product. RESULTS: There were no significant differences between 128-DSCT and 64-MDCT in the vascular density. The VDNR and CNR were higher on 128-DSCT than on 64-MDCT in the aorta (VDNR: 28.9 ± 11.7 vs. 20 ± 5.5; CNR: 24.4 ± 10.9 vs. 16.8 ± 5.4; P<.01), in the pulmonary arteries (VDNR: 25.5 ± 10 vs. 20.6 ± 6.5; CNR: 24.5 ± 5.4 vs. 17.4 ± 6.4; P<.01), and in the coronary arteries (VDNR: 25.9 ± 8.2 vs. 18.9 ± 4.9; CNR: 24.9 ± 8.2 vs. 15.6 ± 4.6; P<.01). There were fewer artifacts in the coronary arteries on 128-DSCT than on 64-MDCT (3 vs. 34 nondiagnostic segments; P<.001), and the ED in 128-DSCT was lower than in 64-MDCT (13.77 ± 4 vs. 2.77 ± 0.6 mSv; P<.001). CONCLUSION: In triple rule-out studies, high pitch 128-DSCT delivers a lower dose of radiation and provides better image quality than retrospective acquisition with 64-MDCT.

Case-control study of writer's cramp.

Task-specific focal dystonias are thought to be due to a combination of individual vulnerability and environmental factors. There are no case-control studies of risk factors for writer's cramp. We undertook a case-control study of 104 consecutive patients and matched controls to identify risk factors for the condition. We collected detailed data on medical history and writing history as part of hobbies or occupation. Cases had a college or university degree more frequently than controls [OR = 4.6 (1.3-20.5), P = 0.01]. The risk of writer's cramp increased with the time spent writing each day (P-trend = 0.001) and was also associated with an abrupt increase in the writing time during the year before onset (OR = 5.7, 95% CI = 1.3-33.9, P = 0.02). Head trauma with loss of consciousness [OR = 3.5 (1.0-15.7), P = 0.05] and myopia [OR = 4.1 (1.7-12.0), P = 0.0009] were both associated with the condition but it was not significantly associated with peripheral trauma, left-handedness, constrained writing, writing in stressful situations or the choice of writing tool. The dose-effect relationship between writer's cramp and the time spent handwriting each day, and the additional burden of acute triggers such as an abrupt increase in the writing time in the year before onset, point to a disruptive phenomenon in predisposed subjects. Homeostatic regulation of cortical plasticity may be overwhelmed, resulting in dystonia.