Image Analysis

In the Imaging Core, MRI is the most commonly used technique for determining total kidney volume, renal blood flow and cardiac analysis, although other methods are used when appropriate.

The Radiology Informatics Laboratory at Mayo Clinic assists the Imaging Core in coordinating image measurement and analytics.

Analysis of kidney and liver volumes

Renal and liver volumes are obtained with coronal T2-weighted images. Nonenhanced 3D, volume-interpolated, spoiled gradient-echo coronal T1-weighted images are obtained at 3 to 4 millimeters contiguous slice thickness.

Individual kidney volume is measured from the T2-weighted images using an automated segmentation method that can be used to calculate total kidney volume and textures and cyst content.

Renal blood flow measurements

Magnetic resonance renal blood flow measurements can be obtained with thick-section, oblique-axial, 2D, phase-contrast, breath-hold magnetic resonance angiograms along the course of each renal artery as reference images. Magnetic resonance renal artery flow measurements are then obtained perpendicular to the oblique-axial, 2D reference images of the renal arteries using a cardiac-gated, 2D, fast gradient-echo, phase-contrast pulse sequence.

Because it can be difficult to obtain reliable measurements, we're now studying 4D flow measurements as a way to increase the reliability of measurements.

Evaluation of cardiac function

MRI is recognized as the gold standard for quantification of ventricular volumes and function. Cardiac function, chamber size and left ventricular mass are determined from short-axis, electrocardiogram-gated, steady-state, free-precession cine images.

After initial localizing scans, two-chamber and four-chamber scout images are acquired and used to prescribe cine short-axis views extending from the base of the left ventricle to the apex. Epicardial and endocardial borders of the left ventricle are traced at end systole and end diastole using commercially available software. Right ventricular volumes, ejection fraction and mass are measured in an identical manner.


Email us for more information about PKD image analysis services offered through the Imaging Core.