Cardiac Analysis

Introduction

The Cardiac Analysis tool is a form of region of interest analysis that is tailored for analysing the myocardium. The left ventricular myocardium can be divided radially into a number of sections so that the different 'territories' of the myocardium can be analysed.

Typically, you will define the endocardial and epicardial borders using a pair of ROIs across a number of cardiac cine 'frames'. You will then tell the tool the number of segments, and indicate where the first segment should begin (the 'insertion point'). You can also optionally divide the myocardium into endocardium and epicardium. You can then perform of an analysis of the signal intensities in each of the segments.

Start the Cardiac Analysis tool from the Toolkits menu: Launching the Cardiac Analysis tool
This will bring up:

The Cardiac Segmental Analysis tool

Image to be Analysed

Load the image to be analysed into Jim's main display. This image is typically a cine cardiac MR image, with multiple time points and possibly multiple slices per time point. You can also analyse cardiac perfusion images with multiple image frames at (typically) mid-systole as the contrast agent bolus passes through the heart. If the image contains more than one physical slice location, then select either:

if the all the time points for the first slice are followed by all the time points for the second slice, etc., or
if all the slices for the first time point are followed by all the slices for the second time point, etc.

If your image has only one physical slice location then this setting doesn't matter.

When the image has been loaded, Jim will attempt to find from the image the number of physical slice locations in the image. However, if Jim cannot find this, and incorrectly sets the wrong number of slices, please set the number manually by clicking on the Checkbox to manually set the number of physical slice locations in the image check box and altering the number of slice locations in the adjacent spinner.

Setting the Number of Segments

The number of radial segments is the same for all time points in an image, but can be varied across the different physical slice locations. For example, if your image contains all time points for a cardiac perfusion sequence, and has three slices (base, mid and apex of the heart, for example) then you could set six segments for the base and mid slices, and four segments for the apex, following the standard AHA segmental analysis procedure.

Once the number of slices has been set correctly, you will see a spinner such as the one below for setting the number of myocardial segments for each physical slice:

Spinner to set the number of myocardial segments for each physical slice locations in the image
Spinner for setting the number of myocardial segments - you will see one for each physical slice location.

Dividing into Sub-Endocardium and Sub-Epicardium

You can further split each segment into a sub-endocardial region and a sub-epicardial region by selecting the Check box to sub-divide the myocardial segments into sub-epicardium and sub-endocardium check box. Selecting this enables the slider for selecting the percentage split between the endo- and epicardium:

Slider to select the split between endocardium and epicardium.

Also shown on the image is the line between the endo- and epi-cardial borders that shows the division between the sub-endocardial and sub-endocardial regions. Moving the slider to the left and right alters the position of that split.

Moving the end/epicardium split slider alters the percentage of the myocardium that is assigned to the sub-endocardium and sub-epicardium.

A myocardial split of 30% endocardium and 70% epicardium	A myocardial split of 70% endocardium and 30% epicardium

Having set the input image and set up the numbers of slices and segments, you can now go on to define the endo- and epi-cardial borders.