Standard B presentation vs. contrast-enhanced ultrasound (US-CE). A comparison of usefulness of different ultrasonographic techniques in the evaluation of the echo structure and size of haematomas inpost-renal transplant patients: A preliminary report

BACKGROUND: During routine ultrasonographic examination in B presentation, performed as a standard diagnostic procedure during the early post-operative period, the most important problem with the interpretation of the images of perirenal haematoma is their ability to change in time. The aim of this work was to assess the echogenicity and the size of perirenal haematomas in patients after kidney transplant during routine examinations in B presentation and during examinations enhanced with a contrast medium (CE-US). MATERIAL/METHODS: Thirty-seven patients after kidney transplant were examined using standard examination in B presentation. Sixteen patients (7 women and 9 men) with isoechogenic and hypoechogenic areas visualized within the renal parenchyma, who were suspected of perirenal haematoma, underwent a CE-US examination after intravenous administration of sculpture hexafluoride (dose: 2.4 ml/examination). Using time-intensity curves (TIC), changes in the values were analysed for two areas of interest (ROI): in the renal parenchyma and in the areas identified during standard US as haematomas. Identical examination protocols and dynamic data loops allowed the acquisition of identical kidney cross-sections and enabled measuring the echogenicity and thickness of the abnormalities at the same location. RESULTS: During the routine B presentation examination, the average difference between haematoma and the renal cortex was 5 dB. When performing US-CE examination, a significantly greater difference in echogenicity was observed and reached 31 dB. In six patients, the size of haematomas was comparable using both techniques, whereas in ten patients lesions visualized in B presentation were smaller than in the US-CE examination. CONCLUSIONS: The US-CE examination demonstrated a greater, statistically significant, difference in the echogenicity of perirenal haematomas compared to the routine examination in B presentation. This method enabled a more detailed assessment of the size of haematomas in the perirenal space that appeared during early post-operative period.