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Ferumoxytol-enhanced MRI for planning hemodialysis AV access

Ferumoxytol (Frx) is an MRI contrast media with no toxicity concerning gadolinium-based contrast in ptns with progressive kidney disease.


Ferumoxytol (Frx)-enhanced MRI for planning hemodialysis (HDX) AV access (Oct 2020)


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Ferumoxytol (Frx) is an MRI contrast media with no toxicity concerning gadolinium-based contrast in ptns with progressive kidney disease. Study: imaging the vasculature of 59 ptns before HDX A/V fistula development, Frx-enhanced MRI identified 15 central venous lesions & significantly more arterial partition that are not amenable for AV fistula creation as compared with US (37 vs 26 %). The simultaneous evaluation of central & peripheral venous anatomical details with FE-MRI was more comprehensive for the AV fistula longevity than using peripheral venous assessment alone or via using US. According to the conclusions of this study, FE-MRI seems to be more beneficial for ptns with:

1)    Prior access failure.

2)    Borderline vasculature via duplex US, or

3)    Associated risk for central venous stenosis or PVD.

Stoumpos S, Tan A, Hall Barrientos P, et al. Ferumoxytol MR Angiography versus Duplex US for Vascular Mapping before Arteriovenous Fistula Surgery for Hemodialysis. Radiology 2020; 297:214.


Ferumoxytol (Frx)-enhanced imaging


Frx is composed of ultra-small paramagnetic Fe oxide embedded in a CHO coating & got the approval of the US FDA as a therapeutic iron supplement. It is cleared from the circulation via the reticuloendothelial system macrophages of the liver, spleen, & bone marrow. Considering its iron content, Frx can be used as a contrast medium for the MRI testing ("off label"). Frx has prolonged ½ -life (15 h.) that permits the imaging of both venous & arterial vasculature with no need for bolus timing, with excellent imaging results for peripheral & central veino-arterial system.

The introduction of Frx-enhanced MR for vascular assessment prior to AV access development has been reported. Study: 59 ptns, 51 AV fistulas were developed, of which 24 (47 %) succeeded. 15 central venous lesions were not reported before were recognized. Frx- MR angiography & duplex US recognized the same number of peripheral venous partitions unsuitable for fistula development; however, Frx-enhanced MR recognized more unsuitable arterial partitions (37 vs 26 %). Accuracy of imaging for predicting AV fistula development success was identified according to:

1)    Age, sex, & US reports

2)    Frx-MR angiography of peripheral vasculature alone.

3)    Frx-MR angiography of central & peripheral vasculature.

Among the 3 models studied, Frx -enhanced angiography of the central & peripheral vasculature predicted AV fistula longevity is the best. The inter-reader agreement for measurements of the arterial diameter, venous diameter, and vein depth from skin surface was quite excellent. Frx is safe for MRI of ptns who had not yet commencing DX, with no concerns about toxicity related to iodinated or gadolinium-content contrast media. However, some allergic reactions may occur. Frx should not be administrated to ptn with allergic history to any IV iron agent. Despite more costly as compared to US, Frx-enhanced MR angiography seems to be more beneficial to ptns with borderline vessels via duplex US or prior access failure, and with the risky central veins for stenosis or PVD.