What is already known about this topic and why is it important?

Current methods of scanning the kidneys are extremely limited. Most patients with kidney disease are assessed with a basic ultrasound scan that provides only a small amount of information about the structure of the kidneys, and no information on their function or the type of disease affecting them. New methods of scanning the kidneys, in particular magnetic resonance imaging (MRI), offer significant advantages. MRI can show the entire kidney in more detail than ultrasound and there is a range of MRI techniques that can assess different aspects of kidney function. Combining several different MRI techniques into a single scan session is called multiparametric MRI. Multiparametric MRI can assess processes that influence or cause kidney disease, such as changes in blood flow, oxygen levels and the degree of scarring (fibrosis). Importantly, MRI scans do not use radiation (unlike X-Rays and CT scans), nor do they need injections of dye (contrast) sometimes needed for other types of scan. This means that MRI scans are completely safe and can be repeated to see whether patients are improving in response to treatment or not. Multiparametric MRI is not yet used in patient care, so we want to perform a research study to establish its usefulness to patients with chronic kidney disease (CKD).

How will you carry out your study?

The research study will have three parts. Firstly, at each of the nine research sites the multiparametric MRI session will be tested in a small number of patients to ensure that they can tolerate all parts of the procedure, including the length of time within the scanner. We will also check that the way we plan to analyse the scans is functioning. Following this, the second part of the study will use multiparametric MRI to evaluate 450 patients with CKD. They will have a multiparametric MRI scan and a clinical check-up of their kidney function at the start of the study, then their progress will be followed and their kidney function assessed with annual check-ups. Where possible, we will aim for these check-ups to coincide with patients’ routine clinic appointments to minimise the burden of taking part in the research. Multiparametric MRI will be repeated after two years and we will study which aspects of the MRI scans change in patients with worsening CKD as compared to those with stable kidney function. We are now applying to the UKRR so that patients’ longer-term kidney health can be monitored via the UK Renal Registry without patients needing to return to the hospital. The third aspect of the research study will focus on a smaller group of patients who take part in the research but who have also had a kidney biopsy as part of their usual care. A biopsy is currently the only way to directly see disease processes inside a patient’s kidneys. Analyses to compare MRI results against kidney biopsy will be performed to provide additional, more detailed evidence as to how multiparametric MRI can be used to visualise different disease processes that lead to CKD and other benefits that may support its use. Results from this research will pave the way for the future use of MRI for the care of patients with kidney disease.

How will you decide which patients are included in your study?

Inclusion criteria:

• Age 18-75 years
• CKD category G3-4 (eGFR 15-60ml/min/1.73m2) OR CKD category G1-2 (eGFR ≥60ml/min/1.73m2) with overt albuminuria (urine ACR>30mg/mmol)
• Capable of giving informed consent

Exclusion criteria:

• Autosomal dominant polycystic kidney disease (ADPKD)
• Glomerulonephritis (GN) actively receiving immunosuppression, or having done so within the preceding 90 days.
  • • Note: GN not requiring immunosuppression (e.g. most cases of IgA nephropathy) will be eligible for inclusion.
    • Immunosuppression defined as any of: >10mg per day of prednisolone or equivalent corticosteroid; calcineurin inhibitor; cytotoxic agent (e.g. cyclophosphamide); azathioprine; mycophenolate mofetil; specific monoclonal antibodies for GN (e.g. Rituximab, Belimumab).
• Multiple myeloma (MM)
• Acute Kidney Injury (AKI) within the 90 days prior to consent (AKI defined as per KDIGO criteria [1])
• Solid organ transplant
• Known single kidney
• More than five simple cysts in one kidney on previous renal imaging
• Contraindications to MRI (e.g. permanent pacemaker, metallic foreign bodies, extensive tattoos, claustrophobia etc.)

How many patients do you anticipate including?

450 participants will be enrolled in the study

For how long will you follow up these patients?

Standard follow up (visits) will take place upto 4 years from the participant’s baseline visit. We are applying to collected long term health data on end stage kidney disease at 5 and 10 years via the UKRR

What value will UKRR data add to the project?

CKD studies can be challenging because in some people with CKD, progression (i.e. declinie in renal function) can happen slowly over a number of years. It is therefore important in CKD cohort studies (such as this one) that adequate follow up duration is planned. Involvement of the UKRR will allow this to happen, and to do so efficiently without patients returning for follow up visits up until 10 years. In addition, serum creatinine values via Patient View will allow calculation of eGFR over this longer follow up period.

What new information will your study generate and how will this benefit patients?

This will provide additional robustness to the findings of studies, helping to show how mpMRI can help in diagnosis and monitoring of patients, with the ultimate goal of improving treatment pathways.