Novel Uses of Ultrasound to Assess Kidney Mechanical Properties

Abstract

Ultrasound is a key imaging tool for the evaluation of the kidney. Over the last two decades, methods to measure the mechanical properties of soft tissues have been developed and used in clinical practice, though the use in the kidney has not been as widespread as for other applications. The mechanical properties of the kidney are determined by the structure and composition of the renal parenchyma as well as the perfusion characteristics. As pathological processes change these factors, the mechanical properties change and can be used for diagnostic purposes as well as monitoring treatment or disease progression. Ultrasound-based elastography methods for evaluating the mechanical properties of the kidney use focused ultrasound beams to perturb the kidney and then high frame rate ultrasound methods are used to measure the resulting motion. The motion is analyzed to estimate the mechanical properties. This review will describe the principles of these methods and discuss several seminal studies related to characterizing the kidney. Additionally, an overview of the clinical use of elastography methods in native and kidney allografts will be provided. Perspectives on future developments and uses of elastography technology along with other complementary ultrasound imaging modalities will be provided.

Using dynamic optical coherence elastography to measure material properties

“…This involves changes in the nephrons of the kidney and anatomy of the kidney tissue. As a result, the mechanical properties of the kidney can be altered with disease [19]. Ex vivo porcine kidneys were used for OCE and ultrasound SWE investigation, both using ARF excitation to generate the waves.…”

Fatty kidney disease: The importance of ectopic fat deposition and the potential value of imaging

“…47 Ultrasound elastography of the kidney may be a technique to measure renal fat content. 48 Sonographic evaluation of para-and perirenal fat thickness has been used as a predictor of early kidney damage in obese patients. 35 Bmode renal ultrasound targeting perirenal fat thickness in specific locations is showing promise.…”

Recent Methods for Modifying Mechanical Properties of Tissue-Engineered Scaffolds for Clinical Applications

“…Hydrogels are typically composed of naturally derived constituents such as collagen, gelatine and hyaluronic acid, and metals used for scaffolds can include magnesium, tantalum, and titanium [ 26 , 36 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 ]. The broad range of characteristics of these materials allows for a vast range of tissue types to be mechanically accounted for; an overview of the typical strength of these material groups in comparison to the stiffness of organic tissues is given in Figure 1 [ 32 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 ].…”

“…Hydrogels are typically composed of naturally derived constituents such as collagen, gelatine and hyaluronic acid, and metals used for scaffolds can include magnesium, tantalum, and titanium [26,36,[39][40][41][42][43][44][45][46][47][48][49][50][51][52][53]. The broad range of characteristics of these materials allows for a vast range of tissue types to be mechanically accounted for; an overview of the typical strength of these material groups in comparison to the stiffness of organic tissues is given in Figure 1 [32,[54][55][56][57][58][59][60][61][62][63][64][65][66][67]. To address this challenge, tissue engineering researchers are investigating a broad range of solutions to optimise the mechanical response of tissue-engineered grafts, while also maintaining the biocompatibility of the design.…”