Liver enhancement in healthy dogs after gadoxetic acid administration during dynamic contrast-enhanced magnetic resonance imaging.

Dynamic contrast enhanced (DCE)-magnetic resonance imaging (MRI) consists of acquisition of native baseline images, followed by a series of acquisitions performed during and after administration of a contrast medium. DCE-MRI, in conjunction with hepatobiliary-specific contrast media, such as gadoxetic acid (GD-EOB-DTPA), allows for precise characterisation of the enhancement pattern of the hepatic parenchyma following administration of the contrast agent. The aim of the study was to assess the pattern of temporal resolution contrast enhancement of the hepatic parenchyma following administration of GD-EOB-DTPA and to determine the optimal time window for post-contrast assessment of the liver. The study was carried out on eight healthy beagle dogs. MRI was performed using a 1.5T scanner. The imaging protocol included T1 weighted (T1-W) gradient echo (GRE), T2 weighted (T2-W) turbo spin echo (TSE) and dynamic T1-W GRE sequences. The dynamic T1-W sequence was performed using single 10mm thick slices. Regions of interest (ROIs) were chosen and the signal intensity curves were calculated for quantitative image analysis. The mean time to peak for all dogs was 26min. The plateau phase lasted on average 21min. A gradual decrease in the signal intensity of the hepatic parenchyma was observed in all dogs. A DCE-MRI enhancement pattern of the hepatic parenchyma was evident in dogs following the administration of a GD-EOB-DTPA, establishing baseline data for an optimal time window between 26 and 41min after administration of the contrast agent.

Role of Diffusion Tensor MR Imaging in Degenerative Cervical Spine Disease: a Review of the Literature.

In the article we review the current role of diffusion tensor imaging (DTI), a modern magnetic resonance (MR) technique, in the diagnosis and the management of cervical spondylotic myelopathy (CSM), the most serious complication of degenerative cervical spine disease (DCSD). The pathogenesis of DCSD is presented first with an emphasis placed on the pathological processes leading to myelopathy development. An understanding of the pathophysiological background of DCSD is necessary for appropriate interpretation of MR images, both plain and DTI. Conventional MRI is currently the imaging modality of choice in DCSD and provides useful information concerning the extent of spondylotic changes and degree of central spinal canal stenosis; however its capability in myelopathy detection is limited. DTI is a state of the art imaging method which recently has emerged in spinal cord investigations and has the potential to detect microscopic alterations which are beyond the capability of plain MRI. In the article we present the physical principles underlying DTI which determine its sensitivity, followed by an overview of technical aspects of DTI acquisition with a special consideration of spinal cord imaging. Finally, the scientific reports concerning DTI utility in DSCD are also reviewed. DTI detects spinal cord injury in the course of DCSD earlier than any other method and could be useful in predicting surgical outcomes in CMS patients, however technical and methodology improvement as well as standardization of acquisition protocols and postprocessing methods among the imaging centers are needed before its implementation in clinical practice.