OBJECTIVE: Early diagnosis of voiding dysfunction can minimize social and psychological repercussions and avoid renal lesions. The ureteric jet can be evaluated by color Doppler, and a good correlation has been observed between this method and patients' clinical data in the diagnosis of voiding dysfunction. This study was aimed at evaluating the interobserver agreement in the assessment of the ureteral jet in asymptomatic children. MATERIALS AND METHODS: Interobserver agreement was prospectively evaluated. A total of 41 patients were sequentially evaluated by two medical sonographers. For each patient, three consecutive Doppler waveforms were obtained from each of the two ureteral jets. The number of peaks on each wave was observed and classified. The maximum velocity of the highest peak of each waveform was also observed. Kappa coefficients (κ) were calculated. RESULTS: Moderate interobserver agreement was observed (κ = 0.48; 95% confidence interval: 0.36-0.60). Most frequently a plateau pattern was observed for the ureteric jet. Maximum velocities measured by the two observers were respectively 32.37 cm/s and 35.63 cm/s. CONCLUSION: Moderate interobserver agreement was observed in the evaluation of the ureteric jet by means of color Doppler.

Keywords: Ureter, Urination, Children

The acquisition of images with suppression of the fat signal is very useful in clinical practice and can be achieved in a variety of sequences. The Dixon technique, unlike other fat suppression techniques, allows the signal of fat to be suppressed in the postprocessing rather than during acquisition, as well as allowing the visualization of maps showing the distribution of water and fat. This review of the Dixon technique aims to illustrate the basic physical principles, to compare the technique with other magnetic resonance imaging sequences for fat suppression or fat quantification, and to describe its applications in the study of diseases of the musculoskeletal system. Many variants of the Dixon technique have been developed, providing more consistent separation of the fat and water signals, as well as allowing correction for many confounding factors. It allows homogeneous fat suppression, being able to be acquired in combination with several other sequences, as well as with different weightings. The technique also makes it possible to obtain images with and without fat suppression from a single acquisition. In addition, the Dixon technique can be used as a quantitative method, allowing the proportion of tissue fat to be determined, and, in more updated versions, can quantify tissue iron.

Keywords: Magnetic resonance imaging; Dixon technique; Fat suppression; Fat quantification; Musculoskeletal system.