Four-dimensional MRI of renal function in the developing mouse

Abstract

The major roles of filtration, metabolism, and high blood flow make the kidney highly vulnerable to drug-induced toxicity and other renal injuries. A method to follow kidney function is essential for early screening of toxicity and malformations. In this study, we acquired high spatiotemporal resolution (4D) datasets of normal mice to follow changes in kidney structure and function during development. The data were acquired with dynamic contrast-enhanced MRI (via keyhole imaging) and a cryogenic surface coil, allowing us to obtain a full 3D image (125-micron isotropic resolution) every 7.7 seconds over a 50-minute scan. This time course permitted demonstration of both contrast enhancement and clearance. Functional changes were measured over a 17-week course (at 3, 5, 7, 9, 13, and 17 weeks). The time dimension of the MRI dataset was processed to produce unique image contrasts for segmenting the 4 regions of the kidney: cortex (CO), outer stripe (OS) of the outer medulla (OM), inner stripe (IS) of the OM, and inner medulla (IM). Local volumes, time-to-peak (TTP) values, and decay constants (DC) were measured in each renal region. These metrics increased significantly with age, with the exception of DC values in the IS and OS. These data will serve as a foundation for studies of normal renal physiology and future studies of renal diseases that require early detection and intervention.

4D MRI of polycystic kidneys from rapamycin‐treated Glis3‐deficient mice

“…In our results, TTP was significantly slower as early as 3 weeks. TTP was approximately 30 min in non‐cystic areas of polycystic kidneys, whereas TTP was less than 2 min even in the slowest inner medullary region of normal kidneys . Measurements of renal function with TTP can be a sensitive imaging metric of polycystic disease.…”

“…Functional TTP maps were determined from the time-intensity curves (Glis3-null mice). Time-intensity curves from wild-type mice have been reported previously (21). TTP maps as a function .…”

Advancing Cardiovascular, Neurovascular, and Renal Magnetic Resonance Imaging in Small Rodents Using Cryogenic Radiofrequency Coil Technology

“…The same room temperature RF coils are typically used for both applications, commonly a four-element saddle-shaped receiver (RX) array in conjunction with a larger transmit (TX) volume resonator. In vivo MRI of a mouse kidney is perfectly feasible with a mouse CryoProbe (Xie et al, 2014 ; Figure 13 ). However, imaging of both kidneys simultaneously requires a much larger field of view than needed for a single kidney or the heart.…”

“… CryoProbe application in fast DCE-MRI of the mouse kidney (Xie et al, 2014 ) . T1-weighted renal images (top) are shown for 7 out of 390 acquired time points.…”

“…The derived parameters time-to-peak and decay constant reflect the inter-layer functional differences. From Xie et al ( 2014 ) by permission of John Wiley & Sons Limited.…”