[Quality assessment in single-slice spiral brain CT examinations of patients with cerebrovascular accident]. / Evaluación de la calidad de los exámenes de tomografía computarizada de cerebro en la indicación de accidente cerebro-vascular agudo.

OBJECTIVES: Our objective was to apply quality criteria proposed by the European Commission (EC) Guidelines to the brain CT examinations for cerebrovascular accident (CVA) diagnosis at single-slice spiral CT scanners from five different hospitals in the Madrid area. MATERIAL AND METHODS: A sample of 100 brain CT examinations was collected and independently reviewed by five radiologists, to determine the degree of fulfilment of image quality criteria. Dose measurements were performed to estimate the values of the CT dose indexes (CTDIw, CTDIair), the dose length product (DLP), and the effective dose (E). RESULTS: Once the McNemar test was applied to the sample, the number of observers' readings was reduced to three. The quality criteria were, in general, fulfilled, since mean values of image quality score between 80% and 92% were deduced, with variation coefficients per centre in the range of 0.07-0.1. However, both visualization criteria 1.1.2 and 1.1.3 exhibited similar ranges of fulfilment (38% - 94%). The good compliance with critical reproduction criteria in the study reflected the capability of these CT scanners to create images of adequate quality, although optimisation should be achieved in some of the centres. Concerning radiation exposure, the mean values per centre of the dose quantities were in the range of 42-64 mGy for the weighted CTDI (CTDIw), 423-744 mGy x cm for DLP, and 1.1-1.9 mSv for E. CONCLUSIONS: The mean values at three centres were close to but above the reference value proposed by the EC Guidelines for CTDIw (60 mGy), and lower than the corresponding reference level for DLP (1050 mGy x cm). Dose optimisation techniques focused on the adjustment of the CTDIw-related examination parameters were proposed.

Evaluación de la calidad de los exámenes de tomografía computarizada de cerebro en la indicación de accidente cerebro vascular agudo / Quality assessment in single-slice spiral brain ct examinations of patients with cerebrovascular accident

Objetivos. El objetivo del trabajo ha sido aplicar los criterios de calidad propuestos en la Guía de la Comisión Europea sobre criterios de calidad en tomografía computarizada (TC) para exámenes de cerebro en la indicación de accidente cerebro-vascular (ACV) en cinco centros de la Comunidad de Madrid dotados de equipos de TC helicoidal de corte único. Material y métodos. Se ha recogido una muestra de 100 exámenes de cerebro que ha sido analizada independientemente por cinco radiólogos para establecer el grado de cumplimiento de los criterios de imagen propuestos. Se han efectuado medidas de dosis en los centros para estimar los valores de los índices de dosis de TC (CTDIw, CTDIair), el producto dosis-longitud (DLP) y la dosis efectiva (E). Resultados. Después de aplicar las pruebas de McNemar y de Friedman a las evaluaciones, se seleccionaron las correspondientes a tres observadores. En general se cumplieron los criterios de calidad en una proporción alta, con promedios del índice de calidad de imagen por centros entre el 80% y el 92%, y coeficientes de variación entre 0,07 y 0,1. Sin embargo, dos criterios de visualización (el 1.1.2 y el 1.1.3) se cumplieron en una proporción variable según los centros con un rango similar de cumplimiento medio (38%-94%). Los criterios de reproducción crítica se cumplieron en una mayor proporción que los de visualización, reflejando así la capacidad técnica de estos equipos para generar imágenes de calidad adecuada, aunque en algunos centros hay que optimizar los procedimientos. En cuanto a las dosis de radiación, los valores medios del CTDIw por centros estuvieron en el intervalo 42-64 mGy, los del DLP entre 423 y 744 mGy·cm y la dosis efectiva media entre 1,1 y 1,9 mSv. Conclusiones. Los valores medios del CTDIw en tres de los centros estuvieron ligeramente por encima del valor de referencia propuesto en la Guía Europea (60 mGy) y en todos por debajo del correspondiente para el DLP (1050 mGy·cm). Se han analizado y propuesto vías de optimización de la calidad de imagen y la dosis en cada centro

Objectives. Our objective was to apply quality criteria proposed by the European Commission (EC) Guidelines to the brain CT examinations for cerebrovascular accident (CVA) diagnosis at single-slice spiral CT scanners from five different hospitals in the Madrid area. Material and methods. A sample of 100 brain CT examinations was collected and independently reviewed by five radiologists, to determine the degree of fulfilment of image quality criteria. Dose measurements were performed to estimate the values of the CT dose indexes (CTDIw, CTDIair), the dose length product (DLP), and the effective dose (E). Results. Once the McNemar test was applied to the sample, the number of observers' readings was reduced to three. The quality criteria were, in general, fulfilled, since mean values of image quality score between 80% and 92% were deduced, with variation coefficients per centre in the range of 0.07-0.1. However, both visualization criteria 1.1.2 and 1.1.3 exhibited similar ranges of fulfilment (38% -- 94%). The good compliance with critical reproduction criteria in the study reflected the capability of these CT scanners to create images of adequate quality, although optimisation should be achieved in some of the centres. Concerning radiation exposure, the mean values per centre of the dose quantities were in the range of 42-64 mGy for the weighted CTDI (CTDIw), 423-744 mGy·cm for DLP, and 1.1-1.9 mSv for E. Conclusions. The mean values at three centres were close to but above the reference value proposed by the EC Guidelines for CTDIw (60 mGy), and lower than the corresponding reference level for DLP (1050 mGy·cm). Dose optimisation techniques focused on the adjustment of the CTDIw-related examination parameters were proposed

Image quality and dose evaluation in spiral chest CT examinations of patients with lung carcinoma.

A study was undertaken to assess the quality of general chest CT examinations for indication of lung carcinoma according to the criteria proposed in the European Commission (EC) Guidelines, and to investigate their usefulness in the optimization of this practice. The criteria were evaluated for a sample of 100 examinations from five radiology departments in the Madrid area featuring single slice helical CT scanners with special emphasis on radiation dose and image quality. To determine the degree of compliance with the image criteria considered, the examinations were independently evaluated twice by five radiologists from the participating centres. A subsequent selection of the observers was made according to the consistency and independence of their readings. Dose measurements carried out in parallel supplied data to estimate the values of the CT dose indices (CTDI), dose-length product (DLP) and effective dose (E). The results show good compliance with the image criteria used - between 93% and 98% on average at the different sites, with variable degrees of internal deviation. 10 out of a total of 16 criteria proposed in the EC guidelines were met by practically all the examinations in the sample. The average weighted CTDI (CTDI(w)) values per site were in the range of 13-19 mGy; those of DLP were between 263 mGy cm and 577 mGy cm, and those of effective dose between 4 mSv and 9 mSv. The highest mean DLP value was below but close to the reference value proposed in the EC Document (650 mGy cm). In general, a weak correlation or no correlation at all was found between image quality scores and patient dose (DLP).