To use Non-invasive MR Imaging of Renal Physiology and structure to assess patients with Acute Kidney Injury (AKI) and Chronic Kidney Disease (CKD).

Multi centre observational pilot study using novel, contrast free functional renal MRI scans.

A series of functional renal MRI scans will be performed (These scans do not constitute part patients routine clinical care). The results will initially be used to assess renal perfusion and fibrosis in patients with AKI and CKD. Subsequent analysis will be used to identify specific markers on the renal MRI scans that differentiate chronic kidney damage from acute injury to the kidney. Finally results will be used to stratify patients with AKI and CKD into low and high risk of subsequent deterioration in renal function.

AKI Cohort

25 patients with AKI stage 2/3 with or without renal replacement therapy (RRT) will undergo functional renal MRI imaging at day 0, day 90 and day 365.

First Study Scan (Day 0): A functional renal MRI scan will be performed during an admission to hospital with an episode of AKI 2/3. Vital signs and SOFA score will be recorded on the day of the scan.

Renal function assessment will occur± 2 days either side of the scan with an Iohexol clearance test.

Second Study Scan (Day 90): Repeat functional renal MRI imaging will be planned at 90 days (±14 days) after the 1st study scan day.

Renal function assessment will occur±7 days either side of the scan with an Iohexol clearance test.

Third Study Scan (Day 365): The final functional renal MRI imaging will take place 12 months (±30 days) after the 1st study scan day. Renal function assessment will occur±7 days either side of the scan with an Iohexol clearance test.

CKD Cohort:

25 patients with CKD stage 3-4 eGFR 20-59ml/min/1.73m2 will undergo functional renal MRI imaging at day 0, day 7 and day 365.

First Study Scan (Day 0): A functional renal MRI scan will be performed as an outpatient. Vital signs will be recorded on the day of the scan.

Renal function assessment will occur ±7 days either side of the scan with an Iohexol clearance test.

Second Study Scan (Day 7): A functional renal MRI scan will be performed as an outpatient. Vital signs will be recorded on the day of the scan.

Third Study Scan (Day 365): The second functional renal MRI imaging will take place 12 months (±30 days) after the 1st study scan day. Renal function assessment will occur±7 days either side of the scan with an Iohexol clearance test.

Inclusion Criteria:

AKI Patients:

• Acute Kidney Injury stage 2/3 (duration >24 hours) including patients requiring renal replacement therapy
• >18 years & < 95 years
• Able to give informed consent

CKD Patients:

• Patients with CKD Stage 3 - 4 (e GFR> 20 and <60 ml/min)
• >18 years & < 95 years
• Able to give informed consent

Exclusion Criteria:

AKI Patients:

• Renal transplant
• Contraindications to MRI e.g. claustrophobia, cardiac pacemaker, metallic fragments or implants
• Pregnancy or breast feeding or intending pregnancy
• Unable to give consent or understand written information
• Pre-existing CKD of any stage as per eGFR
• Obstructive uropathy
• AKI duration <24hrs, in the opinion of the investigator
• Not medically fit for transfer to MRI scan, in the opinion of the clinical team or the investigator
• Iodine allergy
• Patients unable to comply with basic verbal English commands whilst in scanner due to special communication needs

CKD Patients:

• Renal transplant
• Contraindications to MRI e.g. claustrophobia, cardiac pacemaker, metallic fragments or implants
• Pregnancy or breast feeding or intending pregnancy
• Unable to give consent or understand written information
• Unstable CKD; AKI Stage 1 or more or other unplanned hospital admission within the last 90 days
• Iodine allergy
• Patients unable to comply with basic verbal English commands whilst in scanner due to special communication needs

secondary care patients

1. chronic kidney disease stage 3-4 post renal biopsy
2. Acute kidney injury stage 2-3 during hospital admission