Saúde & Tecnologia (Nov 2015)
Magnetic resonance breast coils: models and image quality
Abstract
In three MRI equipments [1,5 T], we evaluated and compared 3 models of dedicated coils to breast MR Imaging. The image quality variable was quantitatively assessed by the indicators: (i) signal-to-noise ratio (SNR) and (ii) uniformity (U). The qualitative assessment by the voluntaries and Radiographers in a Likert scale, considered: (iii) comfort provided during the examination, (iv) accessibility for interventional breast procedures, (v) handling and positioning by Radiographers, (vi) single or bilateral imaging selection, (vii) 17guidance patient within the magnet. Three female volunteers without related breast disease represents the breast patterns of BIRADS system (35, 53 and 72 years old) were exanimate in all coils and underwent a SPIR (spectral inversion recovery) weighted T2 sequence. It was applied a factorial analysis of variance with five fixed factors without replicates to evaluate if there was significant differences between images, concerning the average of SNR and U in the three coils. The differences were significant with the best performance attributed to the coil Z [SNR (p-value=0, F=277,193) e U (p-value=0, F=1487,95)]. There were significant differences in the images quality obtained by the 3 coils (multiple comparisons Tukey test). To the coil z the values are [SNR (15,08u.a.) e U (0,58u.a.)] so, is these coil that produce the best images. The Y coil had lesser rating in image quality variable: (SNR values of 1.89 and U = 0.06). It was found that the draw position of the ROI (Spearman correlation) does not influence the image quality. The highest rating for comfort was given to the coil X followed by coil Z. The coil model choice is important to perform high quality images, patient comfort and handling in positioning. The study results can contribute to a reduction in financial speculation linked to the commercial approaches of competing manufacturers on the market.
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