MIDAS User Manual01/17/19
MIDAS User Manual
Introduction
This document is the User Manual for the MIDAS application. Contained in the following pages are instructions on how to use all of the features provided by this program, as well as tutorials, a quick start section, and an index. This manual is the main resource available for information about the program. The target audience of this manual is liver transplant surgeons. A familiarity with the organs and images viewed is assumed, however no technical knowledge is assumed. A user with little or no computer knowledge should be able to utilize the MIDAS program by using this manual.
Document Conventions:
Button labels are identified in Italics and actions are identified in Bold.
Quick Start
From the desktop or the program folder in Windows, double-click on the “Midas” icon. This will prompt the user to choose a CT file to load. A CT file has the extension “.mhd” and is a two-dimensional picture of the liver. You can enter a file name location or browse for a file. After a CT file is entered, the user will be prompted to choose a file with the extension “.tre”. Then the user will be prompted to load a file with the extension “.cnc”. Once all three files are loaded, the MIDAS window will appear with a toolbar, menu bar, slide bar, and two image windows. The left window displays slices of the liver in two dimensions, and the right window displays the entire liver in three dimensions.
If the loaded files are not compatible, then the command window will display an error message. In this case, close the command window, reload the MIDAS program and choose an appropriate CT file. Once a CT file has successfully loaded and the two windows display the liver images, the user is ready to begin interacting with the system.
To manipulate the 3D window, you can click the right mouse button to zoom in or zoom out of the 3D liver image by dragging the mouse towards or away from yourself.
The left mouse button, once clicked and held down, can rotate the 3D object in any orientation by dragging the mouse pointer in any direction. The center mouse button, once clicked and held down, can move the 3D image around a 2D plane. In other words, the center mouse button does not rotate the image, but simply moves it to a different position on the screen. To manipulate the 2D window, there are a few more options. The user can scroll up and down through all the two-dimensional slices of the liver in two ways. The first way is to drag the slide rule on the left side of the MIDAS window up or down. The slice number is displayed at the top of the slide rule. The second way is to select the CT Layer radio button. (A ‘radio button’ is one of a set of buttons, only one of which can be selected at any given time.) Then the Plus (+) button shows the next slice into the body and Minus (-) button shows the next slice out of the body.
To movethe 2D liver image around in the 2D window, select the Movement radio button in the middle of the MIDAS window. Once this is selected, the Plus (+), Minus (-), Left (<) and Right (>) buttons in the middle of the MIDAS window will move the 2D image down, up, right and left, respectively.
To zoom in and out on the 2D liver image, select the Zoom 2D radio button in the middle of the MIDAS window. Once this is selected, the Plus (+) and Minus (-) buttons will zoom in and out on the 2D image, respectively.
To center the 2D image to its original position, simply click the Center button in the middle of the MIDAS window. This only affects the position of the image on the screen. It does not affect the slice number or the zoom factor.
The three radio buttons along the top of the 2D window (Sagittal/Axial/Coronal) are the three different views in which the system can display the 2D liver image. The Axial view is default and is set when the system initially loads.
To draw a cutting plane in the 2D window, simply click the mouse inside the window and drag where desired. When satisfied with the cut, click Confirm Cut on the bottom of the screen and the line will change to green. If Confirm Cut is not clicked, the cuts will not be inputted or interpolated. Interpolation is what MIDAS does when the user specifies a cutting plane on two slices that are not next to each other. The cuts on the intermediate slices are approximated by the MIDAS system.
MIDAS allows any number of consecutive cuts to be erased. To erase cuts, enter in the number of slices to erase in the “# slices” text box beside the Undo button. For example, if the number ‘3’ was entered, then the lines drawn on the last three slices would be erased when Undo is clicked. If ‘0’ or ‘1’ is entered in the text box, then the current line will be erased.
To view the major arteries and blood vessels of the liver, click the Overlays (on/off) toggle button.
System Overview
The MIDAS system is intended to help liver transplant surgeons better visualize what will happen in surgery before it happens. This is accomplished by taking pictures of the liver and loading them into the MIDAS system. There are three types of The CT files are then converted into two image windows. The 2D window displays the liver in two-dimensional “slices” and allows the user to scroll through the slices in two directions. This information is loaded into the MIDAS program through files with the extension “.mhd”. The 3D window displays the liver in three dimensions and allows the user to see the image in any orientation by simply clicking on the window and dragging in any direction. This information is loaded into the program through files with the extension “.cnc”.
MIDAS allows users to draw tentative cutting planes on any 2D “slice” of the image. By drawing on consecutive 2D slices, the user can very carefully map out a plan for surgery. The major arteries and blood vessels of the liver are also displayed to further assist the users in planning a surgical cutting plane. This information is loaded into the MIDAS system through files with the extension “.tre”.
Tutorial
Getting Started
To begin using the MIDAS system, first double-click on the “Midas” icon from the desktop or program folder in Windows. This will prompt the user to choose a file to load. Only files with the extension “.mhd” will load successfully. These are called “CT files”. You can either enter a file name location or browse for the file yourself.
After a CT file is entered, the user will be prompted to choose a file with the extension “.tre”. These files provide the major artery information with the liver. Then the user will be prompted to load a file with the extension “.cnc”. These files provide the 3D liver information. Once all three files are loaded, the user will see the MIDAS window appear containing a toolbar, menu bar, and two image windows. The left window displays slices of the liver in two dimensions, and the right window displays the entire liver in three dimensions.
If the loaded files are not compatible, then the command window will display an error message. In this case, close the command window, reload the MIDAS program and choose appropriate files. Once the files have been successfully loaded and the two windows display the liver images, the user is ready to begin interacting with the system.
3D Window
.
To rotate the 3D image around simply click the left mouse pointer anywhere inside the right window, and while holding the mouse button down, drag the pointer around the window in any direction. Upon releasing the mouse button, the image will remain in the position it was in when the button was released and will not move again until you click and drag again.
To move the 3D image around click the center mouse button anywhere inside the right window, and while holding the mouse button down, drag the pointer around the window in any direction. The 3D image will remain in the position it is currently in when the mouse button is released.
To zoom in on the 3D image, click the right mouse button anywhere inside the right window and pull the mouse pointer down the screen towards yourself.
To zoom out on the 3D image, click the right mouse button anywhere inside the right window and pull the mouse pointer up the screen away from yourself.
2D Window
The left window displays slices of the liver in two dimensions. Only one slice is displayed at a time, and the user can scroll up and down through the slices. The current slice number is displayed at the top of the slide bar on the left side of the MIDAS window. The relative slice position is indicated by the position of the slide rule in the slide bar.
Scrolling up and down through the slices can be done in one of two ways. The slide rule on the left can be moved with the mouse to move through slices. Also, if the CT Layer radio button is selected in the middle of the MIDAS window, pressing the Plus (+) and Minus (-) diamond-shaped buttons will scroll up and down through the slices one at a time.
To move the 2D liver image around in the 2D window, select the Movement radio button in the middle of the MIDAS window. Once this is selected, the Plus (+), Minus (-), Left (<) and Right (>) buttons in the middle of the MIDAS window will move the 2D image down, up, right and left, respectively.
To zoom in and out on the 2D liver image, select the Zoom 2-D radio button in the middle of the MIDAS window. Once this is selected, the Plus (+) and Minus (-) buttons will zoom in and out on the 2D image, respectively.
To center the 2D image to its original position, simply click the Center button in the middle of the MIDAS window.
Sagittal, Axial, and Coronal Views
The two-dimensional liver slices can be displayed in three different views Sagittal, Axial, and Coronal. (This manual assumes the user is familiar with these terms.) When the MIDAS window is first opened, one of the three buttons is already selected. The Axial view is default. The user can toggle between the three views by selecting one of the other buttons (Sagittal/Axial/Coronal) that is not currently selected. When one of the other views is selected, the current selection is automatically deselected.
File Menu
The File menu allows the user to exit the MIDAS program. To exit the program, click on ‘FILE => QUIT’ and you will exit the MIDAS system.
Cutting Plane
The MIDAS system allows the user to draw lines on the 2D window so as to specify a cutting plane for surgery. There are two ways to draw a cutting plane. You can either, click the mouse inside the 2D window and drag in any direction, or you can click two points on the 2D window and MIDAS will connect them for you. To keep the cut, simply click Confirm Cut in the bottom of the MIDAS window. If you append to a cut on a slice where you already confirmed the cut, you must confirm again. You can draw on multiple slices. After clicking Confirm Cut, move to the next slice up or down and then specify a cutting plane on that slice. A cutting plane is displayed below in yellow. If the user draws cuts on two slices that are not next to each other and confirms both these cuts, the MIDAS program will interpolate into the skipped slices a “best estimate” cut. In other words, any slices in between two confirmed cuts will be filled in by the MIDAS system.
The “# slices” text box works in conjunction with the Undo button. If cutting planes on multiple 2D slices have already been drawn, MIDAS allows the user to undo any number of slices. To do this, select the number of slides one wishes to undo in the ‘No of Slides’ text box, then click Undo. For example, if the number ‘3’ were entered into the text box, and the user clicked undo, then the lines drawn on the last three slices would be erased.
Overlays
The major arteries and blood vessels of the liver can be displayed in the 2D window on top of the liver image by selecting Overlays (on/off). The overlays are colored in red.
Reference
1. Plus (+) 9. Sagittal
2. Minus (-)10. Axial
- Right (>)11. Coronal
- Left (<)12. File
- Center 13. No. of Slides
- CT Layer 14. Overlays (on/off)
- Movement 15. Confirm Cut
- Zoom 2D 16. Undo
17. Slide Rule
Plus (+)
The Plus button has three functions. The first is to move the liver image up on the 2D window. This is done when the radio button Movement is selected in the middle of the MIDAS window. The second function is to move up to the next 2D slice. This is done when the radio button CT Layer is selected. The third function of the Plus (+) button is to zoom in on the 2D liver image. This is done when the radio button Zoom 2D is selected.
Minus (-)
The Minus button has the same three functions as the Plus button, as one might imagine. The first is to move the liver image down on the 2D window. This is done when the radio button Movement is selected in the middle of the MIDAS window. The second function is to move down to the next 2D slice. This is done when the radio button CT Layer is selected. The third function of the Minus (-) button is to zoom out on the 2D liver image. This is done when the radio button Zoom 2D is selected.
Left (<)
The Left button has one function. It moves the 2D liver image left in the 2D window.
Right (>)
The Right button has the same function as the Left button. It moves the 2D liver image right in the 2D window.
Center
The center button has one function. It re-centers the 2D liver image to the original, default position.
CT Layer
The CT Layer button is one of three radio buttons in the center of the MIDAS window. (A radio button is a one of a set of buttons, only one of which can be selected at a time.)
When it is selected, the Plus (+) and Minus (-) buttons cause the next slice up or down, respectively, to be displayed in the 2D window.
Movement
The Movement button is the second of three radio buttons in the center of the MIDAS window. When it is selected, the Plus (+) and Minus (-) buttons are enabled to move the 2D liver object down and up, respectively. The Left (<) and Right (>) always move the 2D image right and left on the 2D window, no matter whether CT Layer, Movement, or Zoom 2D is selected.
Zoom 2D
The Zoom 2D button is the third of three radio buttons in the center of the MIDAS window. When it is selected, the Plus (+) and Minus (-) buttons zoom in and out, respectively, on the 2D liver image in the 2D window.
Sagittal
The Sagittal button is one of three radio buttons along the top left of the MIDAS window. Selecting the Sagittal button will cause any other selection of the three views to be deselected.
Axial
The Axial button is one of three radio buttons along the top left of the MIDAS window.
When the MIDAS system initially loads, this button is the default selection and the 2D liver image is displayed in Axial view.
Coronal
The Coronal button is the third radio button along the top left of the MIDAS window. Selecting the Coronal button will cause any other selection of the three views to be deselected.
File
The File pull-down menu consists of one option: ‘Quit’. Selecting FILE => QUIT will cause the user to exit the MIDAS system and the MIDAS window will close.
# Slices
The “# slices” text box works in conjunction with the Undo button to erase user-created cutting planes. As the user goes through the numbered 2D slices in the 2D window and draws tentative cuts, MIDAS allows the user to undo any number of slices. For example, if the number entered was ‘2’, then the lines drawn on the last two slices will be erased.