Diffusion tensor imaging in acute pyelonephritis in children

Diffusion-weighted imaging plays a key role in the imaging of acute pyelonephritis by MRI. However the use of respiratory triggering is challenging and time-consuming in children. Diffusion tensor imaging without respiratory triggering might provide satisfying images of the moving kidneys. To compare mean diffusivity diffusion tensor images obtained with free breathing with diffusion-weighted images obtained with respiratory triggering. Thirty-one children with suspected acute pyelonephritis underwent axial diffusion tensor imaging acquisition with free breathing and axial and coronal diffusion-weighted imaging acquisitions with respiratory triggering. We compared image quality and detection of nephritis between the two sequences. Diffusion tensor imaging demonstrated agreement with diffusion-weighted imaging in all cases, with no difference in the detection of nephritis areas. The image quality was significantly better with diffusion tensor imaging (P < 0.01). Diffusion tensor imaging could replace diffusion-weighted imaging for diagnosis of acute pyelonephritis.