Counting glomeruli in human kidney specimens without contrast agents using ex vivo MRI at 16.4 T

Motivation: Glomerular number provides important insight into kidney function. The reference stereology method for glomerular counting is labour-intensive and time consuming, and the current MRI method for glomerular counting is hard to perform as it requires perfusion of contrast agents into the kidney. Goal(s): Our goal is to develop a microimaging method at 16.4 T for counting glomeruli ex vivo, without contrast agents. Approach: Nephrectomy samples were imaged at 30 μm and an automated blob detection method was implemented to count the glomeruli. Results: Our results showed that glomeruli can be identified on the MRI, and glomerular counts from MRI and stereology were similar. Impact: For the first time, we showed that MRI without contrast agents can be used to visualise glomeruli in human kidney specimens. Our approach required minimal handling with the tissues remaining intact post MRI, allowing easy transportation and further experiments.