Diffusion tensor imaging of kidneys with respiratory triggering: Optimization of parameters to demonstrate anisotropic structures on fraction anisotropy maps

Abstract

Purpose:To demonstrate the feasibility of diffusion tensor imaging (DTI) of kidneys with respiratory triggering, and determine the optimal imaging parameters for fraction anisotropy (FA) maps. Materials and Methods:DTI of kidneys from 16 healthy volunteers was performed using a 1.5T scanner. Five different sequences with different parameters including respiration-triggered acquisition or multiple breath-holding, slice thicknesses of 3 or 5 mm, and different numbers of signal averaging and b values were compared. FA and apparent diffusion coefficients (ADCs) of the cortex and medulla were measured. Measurement error within the same and repeated examination was examined using within-individual standard deviation (Sw). Results:FAs of the renal cortex were lower than the medulla (mean value of a sequence ranging 0.148 -0.224, 0.433-0.476) and the ADCs of the cortex were higher than the medulla (2.26 -2.69 ϫ 10 Ϫ3 mm 2 /s, 1.77-2.19 ϫ 10 Ϫ3 mm 2 /s) in all sequences (P Ͻ 0.001). The renal cortexmedulla difference was the largest, with respiratory triggering including a 3-mm slice thickness, three signal averages,and a b-value ϭ 0, 200, or 400 s/mm 2 (P Ͻ 0.001). Sw tended to be smaller in the sequence with a b-value of 400 s/mm 2 . Conclusion: DTI of kidneys with respiratory triggering is feasible with excellent cortex-medulla differentiation.

Diffusion tensor imaging of renal ischemia reperfusion injury in an experimental model

“…FA values of normal rat cortex and medulla were measured to be 0.17 AE 0.01 and 0.36 AE 0.03, respectively. Such large FA difference between renal cortex and medulla is consistent with the known kidney anatomy and previous human DTI studies (24,26), which arises from the diffusion anisotropy in the radially oriented architecture of medulla.…”

“…In vivo DWI and DTI of kidney in rodent models at high magnetic field have been challenging due to the high respiration rates, increased magnetic susceptibility and motion artifacts. By means of respiratory triggering and fast single-shot EPI (26,(34)(35)(36), the image quality can be greatly improved as demonstrated in the current study. MR diffusion imaging measures the combined effects of water diffusion and capillary blood perfusion in tissues.…”

“…Liu and Xie investigated renal IRI using DWI sequences and found that ADC could probe the functional changes during the course of insult (18), providing a noninvasive method for evaluating the disease. Recently, measurement of diffusion anisotropy using diffusion tensor imaging (DTI) has been found to provide additional information about functional and structural status of kidney (24)(25)(26).…”

Diffusion tensor imaging of the kidney at 3 tesla: normative values and repeatability of measurements in healthy volunteers

“…When low b values are used (e.g., <100 s/mm 2 ), ADC results are influenced by intravoxel coherent motion and are improved. In addition, it has been shown that the standard deviation in ADC values is greater when smaller b values are used (16). While deciding the b value in this study, we considered the ADC of the kidney.…”

Diffusion-Weighted MRI for the Healthy Cervical Multifidus: A Potential Method for Studying Neck Muscle Physiology Following Spinal Trauma

“…This observation may represent one physiologic basis for persistent pain in this population; however, the exact physiological mechanisms behind these changes and their relationship to symptoms remains unclear. 12 Diffusion-weighted imaging (DWI), which is a noninvasive method of studying the diffusion of water molecules in many different anatomical tissues (eg, brain and spinal cord, kidneys, heart, lumbar intervertebral disc, and the prostate), 2,3,20,[22][23][24]30,31,16,17,34,35 has the potential to help clarify the existence of such a relationship and to possibly uncover the physiological mechanisms underlying such changes. Normal water diffusion is affected by the presence and orientation of physical tissue barriers (eg, cell membranes, proteins, myelin sheaths, and lipids).…”