Will advances in functional renal magnetic resonance imaging translate to the nephrology clinic?

Abstract

Characterizing structural and tissue abnormalities of the kidney is fundamental to understanding kidney disease. Functional multi‐parametric renal magnetic resonance imaging (MRI) is a noninvasive imaging strategy whereby several sequences are employed within a single session to quantify renal perfusion, tissue oxygenation, fibrosis, inflammation, and oedema without using ionizing radiation. In this review, we discuss evidence surrounding its use in several clinical settings including acute kidney injury, chronic kidney disease, hypertension, polycystic kidney disease and around renal transplantation. Kidney size on MRI is already a validated measure for making therapeutic decisions in the setting of polycystic kidney disease. Functional MRI sequences, T1 mapping and apparent diffusion coefficient, can non‐invasively quantify interstitial fibrosis and so may have a near‐future role in the nephrology clinic to stratify the risk of progressive chronic kidney disease or transplant dysfunction. Beyond this, multi‐parametric MRI may be used diagnostically, for example differentiating inflammatory versus ischaemic causes of renal dysfunction, but this remains to be proven. Changes in MRI properties of kidney parenchyma may be useful surrogate markers to use as end points in clinical trials to assess if drugs prevent renal fibrosis or alter kidney perfusion. Large, multi‐centre studies of functional renal MRI are ongoing which aim to provide definitive answers as to its role in the management of patients with renal dysfunction.

Daytime Variation in Kidney Perfusion, Oxygenation, and Sodium Concentration Assessed by Multiparametric MRI in Healthy Volunteers

“…8 Functional and multiparametric MRI of the kidney are under thorough investigation as a tool to obtain noninvasive, clinically important information, that could guide treatment of kidney diseases. 9 The emergence of sodium MRI has sparked interest for imaging of the corticomedullary gradient in patients with kidney diseases. 3,10 While multiparametric and 23 Na-MRI is known to be sensitive to pathological changes in controlled experiments, its technical and physiological inter-and intra-individual variation over a day has not been fully studied.…”

Noninvasive Assessment of Diabetic Kidney Disease With MRI: Hype or Hope?

“…Recognizing this unmet clinical need and opportunity, this review focuses on the role of MRI for the noninvasive assessment of DKD and seeks to present knowledge complementary to previous reviews. [21][22][23][24][25] Key concepts and current trends in renal MRI technology for tissue characterization and for guiding or supplementing clinical decision-making are outlined. Recent progress in clinical and preclinical studies are surveyed, and challenges for clinical translation of renal MRI techniques are addressed.…”

Editorial for “Exploration of Interstitial Fibrosis in Chronic Kidney Disease by Diffusion‐Relaxation Correlation Spectrum MR Imaging: A Preliminary Study”

“…MR methods for quantifying IF frequently focused on T1 or T2 relaxation times in literature, as well as different diffusion‐weighted imaging‐based models and metrics 2 . While results are promising overall, there is no established proof of reproducibility and true clinical impact.…”

“…1 State-of-the-art imaging techniques can only evaluate CKD at a macroscopic level, for example, by showing reduced renal volume and loss of corticomedullary differentiation. 2 However, there is an everincreasing interest in magnetic-resonance (MR)-based functional methods as tools for exploiting the microscopic environment of CKD, including interstitial fibrosis (IF). IF is the hallmark of disease and a key prognostic and risk stratification feature.…”

“…3 MR methods for quantifying IF frequently focused on T1 or T2 relaxation times in literature, as well as different diffusion-weighted imaging-based models and metrics. 2 While results are promising overall, there is no established proof of reproducibility and true clinical impact. It has been supposed that combining different MR indexes might better balance reciprocal advantages and disadvantages and maximize diagnostic capabilities.…”