3% and 56.7% only [3]. Technical developments have increased the capabilities of ultrasound since then. A recent prospective study on detection of acute pyelonephritis with contrast-enhanced ultrasound of renal transplants Rapamycin order found a sensitivity and specificity of 95% and 100% compared to contrast-enhanced T1w-MR imaging as standard of reference with excellent inter-modality agreement of K = 0.92 [13]. However, no use was made of DWI-MRI in this study. Looking closer at our data it seems that particularly in those patients with minor foci of infection or without abscess formation, the sensitivity of DWI imaging differs most from T1w and T2w imaging and clearly demonstrates foci of infection which can neither be seen nor be characterized due to too small size.

A noticeable characteristic of DWI is that in the source data with high b values (i.e., b = 800smm2) even the smallest foci of infection are displayed with high lesion-to-background contrast. This high conspicuity of inflammatory changes in combination with the assumed high sensitivity could foster the use of DWI as a primary tool for workup of complicated patients or patients with impaired renal function. As CT is increasingly often recognized as major source of radiation exposure for the general population, some experts recommend ��to replace CT use, when practical, with other options, such as magnetic resonance imaging (MRI)�� [14]. In the setting of infectious renal disease where many nononcologic patients and younger patients are being examined this is of even higher importance.

In pediatric patients the comparable radiation dose is on average 24% higher compared to the already high dose in abdominal studies in adults [15]. Especially for pediatric patients DWI-MRI of the kidneys seems Batimastat to be a perfect match combining a radiation-free examination of the abdomen with high robustness to motion as it can be acquired during continuous breathing. When applying DWI imaging to the kidneys to identify infectious foci, some caveats have to be considered. First, it is well known that chronic hydronephrosis and resulting renal fibrosis might lead to decreased ADC values of the kidneys [16, 17]. Also transplant kidneys with acute deterioration of function were found to have lower ADC values in one study than transplants with normal function [18]. Unlike the diffuse diffusion restriction seen in the latter two mentioned clinical settings, findings of infectious renal disease are often patchy and irregular and barely ever affect the entire kidney homogenously. Also, the usual clinical presentation of these patients will differ significantly. The diffusion restriction in DWI can be absolutely quantified by means of the apparent diffusion coefficient (ADC).