Diffusion-weighted MRI sequences (DW-MRI) of the kidney: normal findings, influence of hydration state and repeatability of results.

PURPOSE: This study was performed to determine the apparent diffusion coefficient (ADC) of the normal kidney using diffusion-weighted magnetic resonance imaging (DW-MRI) sequences and to analyse both the changes due to hydration state and results repeatability. MATERIALS AND METHODS: Ten volunteers underwent DW-MRI imaging of the kidneys with a breath-hold single-shot spin-echo planar imaging (SE-EPI) sequence in the axial and coronal planes with b values of 300, 500, 800 s/mm(2), in different states of hydration. Urine osmolarity (OsmU) and sodium excretion (NaU) were measured at the time of each examination. ADC maps were created for all b values, and ADC values were calculated and compared between different states of hydration. In five subjects, the protocol was conducted twice to test data repeatability. RESULTS: ADC values were lower with higher b values (3.00 vs. 2.47 vs. 1.99 x 10(-3) mm(2)/s with b values of 300, 500, 800 s/mm(2), respectively). ADC values in different hydration states were not statistically different. Measurements were reproducible. OsmU and NaU were statistically different in the different states of hydration (p<0.01). CONCLUSIONS: ADC values significantly decrease with higher b values. Average ADC values in the normal kidney are reproducible. Hydration state does not significantly influence mean ADC values.

Traumatic lesions of adrenal glands in paediatrics: about three cases.

Pediatric adrenal injuries, in blunt thoracoabdominal trauma, are rare and usually associated with traumatic liver and kidney lesions. This paper aims to present imaging findings and possible adrenal involvement in blunt abdominal traumas in childhood. We report three cases of thoracoabdominal trauma with adrenal involvement. Two patients were polytraumatised in car accidents. The third case was unusual because of the mild trauma. The adrenals lesions were right-sided in all cases. Post-traumatic adrenal contusion/haematoma may arise not only because of a direct trauma but also as a consequence of a sudden increase in the pressure in the inferior vena cava system-adrenal veins. This is why adrenal haemorrhage is not directly proportional to the trauma: compression of the inferior vena cava leads to increased pressure in the adrenal venous circulation, which supports the parenchymal lesion. The right adrenal gland is more frequently injured than the left gland: it can be easily compressed between the liver, spine and kidney, and its venous drainage flows directly into the inferior vena cava.