Functional Magnetic Resonance Imaging in Acute Kidney Injury: Present Status

Abstract

Acute kidney injury (AKI) is a common complication of hospitalization that is characterized by a sudden loss of renal excretory function and associated with the subsequent development of chronic kidney disease, poor prognosis, and increased mortality. Although the pathophysiology of renal functional impairment in the setting of AKI remains poorly understood, previous studies have identified changes in renal hemodynamics, perfusion, and oxygenation as key factors in the development and progression of AKI. The early assessment of these changes remains a challenge. Many established approaches are not applicable to humans because of their invasiveness. Functional renal magnetic resonance (MR) imaging offers an alternative assessment tool that could be used to evaluate renal morphology and function noninvasively and simultaneously. Thus, the purpose of this review is to illustrate the principle, application, and role of the techniques of functional renal MR imaging, including blood oxygen level-dependent imaging, arterial spin labeling, and diffusion-weighted MR imaging, in the management of AKI. The use of gadolinium in MR imaging may exacerbate renal impairment and cause nephrogenic systemic fibrosis. Therefore, dynamic contrast-enhanced MR imaging will not be discussed in this paper.

Magnetic resonance imaging evaluation of renal ischaemia–reperfusion injury in a rabbit model

“…; Zhou et al . ). These technical limitations confound interpretation of the renal oxygenation measurements.…”

“…It is unknown whether IRI patients with high R2 * (the rate of magnetic spin dephasing) values have more progressive disease than those with lower R2 * values, and longitudinal follow‐up studies are therefore eagerly awaited (Zhou et al . ).…”

“…; Zhou et al . ). These techniques are non‐invasive and do not require the administration of a gadolinium contrast agent, and patients with renal insufficiency can be examined without risk.…”

“…Moreover, renal IRI has been detected on T2WI and T2 * WI, but low image contrast and motion artefact at longer echo times (TEs) limit their sensitivity (Zhou et al . ). These technical limitations confound interpretation of the renal oxygenation measurements.…”

Contrast-enhanced ultrasound: A promising method for renal microvascular perfusion evaluation

“…Although functional MRI can be performed without contrast agents, the invasive nature of the pharmacological or physiological manipulations associated with this approach [9] , and the lack of standardized sequences, post-processing software and models hinder its routine application in the clinic [10] .…”