The Role of Arterial Spin Labeling Functional MRI in Assessing Perfusion Impairment of Renal Allografts: A Systematic Review

Abstract

Arterial spin labeling (ASL) is a functional magnetic resonance imaging (fMRI) technique that uses water in arterial blood as a tracer to map an area of interest where the intravascular and extravascular compartments exchange. Our review article focuses primarily on the role of ASL fMRI in assessing perfusion impairment in renal allografts in order to take appropriate steps to eliminate the cause of perfusion impairment at an early stage, thereby extending graft life. The study also highlights various other fMRI techniques that are used to analyze other parameters that affect kidney transplants both acutely and chronically. We gathered our data in accordance with the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and our search strategy included exclusion/inclusion criteria. Several databases were used in the search strategy, including PubMed, Cochrane, and Science Direct, and the Medical Subject Headings (MeSH) strategy was specifically used for PubMed, and two people scrutinized those papers to conclude that a total of 10 research papers are included in our study. This review article includes papers involving 20 to 98 subjects who had renal allografts within the previous six months and had renal cortical perfusion values measured by ASL fMRI ranging from 35 to 304 ml/100 g/min. Furthermore, when compared to healthy kidney transplant patients, renal ASL perfusion values were significantly lower in subjects with the functional imbalance of kidney transplants. It had a positive correlation with the estimated glomerular filtration rate (eGFR). To summarize, ASL fMRI is critical in detecting renal allograft perfusion impairment.

Keywords: asl fmri; chronic renal failure; renal allograft; renal magnetic resonance; renal perfusion imaging; renal transplantation..

Figure 1. Data extraction process using the PRISMA flowchart 2020

* the number of records identified from each database or register searched (rather than the total number across all databases/registers) ** the number of records were excluded by a human and by automation tools PRISMA - Preferred Reporting Items for Systematic Reviews and Meta-Analysis

Figure 2. Various fMRI techniques with their functions

fMRI - functional magnetic resonance imaging; BOLD fMRI - blood oxygen level-dependent fMRI; DWI fMRI - diffusion-weighted fMRI; DCE fMRI - dynamic contrast-enhanced fMRI; ASL fMRI: arterial spin labeling fMRI The original image is owned by the corresponding author.

Figure 3. Limitations faced at the time of review

ASL - arterial spin labeling The original image is owned by the corresponding author.