DOI:10.2214/AJR.06.0515
AJR 2007; 188:W384-W388
© American Roentgen Ray Society
Medical Illustration Techniques for PowerPoint: Part 2, Practical Applications
Omar Lababede1 and
Moulay Meziane
1 Both authors: Department of Diagnostic Radiology, Section of Thoracic Imaging,
The Cleveland Clinic, 9500 Euclid Ave., HB6, Cleveland, OH 44195.
Received April 18, 2006;
accepted after revision August 31, 2006.
Address correspondence to O. Lababede
(lababeo{at}ccf.org).
WEB This is a Web exclusive article.
Abstract
OBJECTIVE. Our purpose is to present a step-by-step example of how
to use PowerPoint (Microsoft) drawing techniques to make a medical
illustration.
CONCLUSION. The newer versions of PowerPoint have useful drawing
tools that can enhance radiologic presentations. Using a simplified approach
and with practice, users should be able to draw high-quality medical
illustrations.
Keywords: digital imaging • PowerPoint
Introduction
The newer versions of PowerPoint (Microsoft) have built-in drawing
tools that can be used to enrich radiologic presentations. In part 1
[1] we describe basic
techniques of vector drawing. In this article we present our approach to
drawing with PowerPoint. We illustrate the techniques using an example. The
methods presented are those that work for us. As users become familiar with
the software, they can develop their own approaches through practice and trial
and error.
The core illustration used in the step-by-step approach is a diagram
depicting the anatomy of the retroperitoneal and interfascial planes. This
diagram exemplifies the crucial educational role of medical illustrations.
Retroperitoneal anatomy is essential for understanding the spread of
retroperitoneal fluid collections and infiltrative processes in a variety of
infectious, neoplastic, inflammatory, and traumatic diseases
[2]. However, this anatomy is
difficult to teach with a text-only approach. Moreover, the structures
depicted cannot be described efficiently with normal cross-sectional images.
This problem occurs because many retroperitoneal spaces are not true spaces
but are merely expansile potential spaces seen mostly in pathologic
conditions. Using abnormal cases to teach basic retroperitoneal anatomy is not
an accurate or practical approach because many cases would be needed for
comprehensive description.
Step-by-Step Drawing of a Medical Illustration Using PowerPoint
When drawing with PowerPoint, which generates vector graphics, one should
rethink the drawing process. The illustration elements are considered in terms
of objects. Each object is composed of adjustable line segments that define an
area with color and shade. The objects are considered layers with the most
recently drawn on top. To facilitate drawing, certain buttons should be
permanently displayed rather than accessed through the menus. Before beginning
the following steps, refer to the toolbar settings described in part 1
[1]. The toolbars eventually
can be rearranged according to personal preference and practical needs. Figure
4A,
4B of part 1 lists the drawing
tools frequently used in the following discussion.
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Fig. 4A —PowerPoint (Microsoft) screen shots show refinement of contours of
pancreas (top), inferior vena cava and aorta (middle), and
vertebral body (bottom). Objects were drawn at later stage but are
shown for relevance. Dashed lines separate structures to show they have been
captured from different screens to show anchor points of all objects (Edit
Points can be applied to only one object at same time). Initial drawings
prepared with Curve tool, except for pancreas (top), which was drawn
with Freeform tool.
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Fig. 4B —PowerPoint (Microsoft) screen shots show refinement of contours of
pancreas (top), inferior vena cava and aorta (middle), and
vertebral body (bottom). Objects were drawn at later stage but are
shown for relevance. Dashed lines separate structures to show they have been
captured from different screens to show anchor points of all objects (Edit
Points can be applied to only one object at same time). Adjusted refined
drawing. Techniques used are dragging anchor points to more precise location,
adding points by clicking and dragging, and deleting points. Symmetric
repositioning of anchor points produces shapes that are closer to symmetric,
as is case with aorta and inferior vena cava.
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Step 1: Template Preparation
Template preparation is essential because it facilitates computer-generated
drawing. One method of making a template is to hand sketch the illustration
and transform it into digital format using a scanner or digital camera. A
better method is to use a digitally saved radiologic image as a template. Use
of radiologic images saves time and produces superior drawings. In addition to
cross-sectional images, coronal MR and reconstructed CT images can be used.
Radiographs and 3D CT renderings are used for diagrammatic representation of
3D subjects.
Insert the template or sketch into a slide and adjust its size and use
cropping to show the pertinent portion of the image. In the example
retroperitoneal anatomic illustration, the template is an axial CT image of
the abdomen (Fig. 1). To insert
an image into a slide, use the Insert menu and select Picture then From File.
Details about acquiring digital images and inserting images into slides are
beyond the scope of this article and are described in the literature
[3,
4].
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Fig. 1 —42-year-old man with normal abdominal findings. PowerPoint
(Microsoft) screen shot shows CT image inserted into slide presentation for
use as template. Image is axial CT scan of abdomen at level of renal hila.
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Step 2: Drawing Objects
Selecting which object to draw first varies with the nature of the
illustration. In general, begin drawing the main elements from the back and
move to the front, because each new object behaves as a new layer that
sequentially overlies each previously drawn object. Use the Curve and Freeform
tools, described in part 1 [1],
to draw different objects (elements) of the illustration. Selecting which tool
to use is based primarily on personal preference and experience. We have found
the Curve tool most appropriate for objects with large, smooth curves. The
Freeform tool, on the other hand, is best for objects with irregular contours.
When drawing, ignore fine details at first. That is, do not aim for precision
at this point. This simpler approach facilitates drawing of more complex
objects, such as those with fine, jagged contours. After drawing a single
object, repeat steps 2 through 4 for each object. An alternative is to draw
multiple objects or all objects in step 2 and then proceed to step 3. In this
example, we first draw the outline of the abdominal wall
(Fig. 2).
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Fig. 2 —PowerPoint (Microsoft) screen shot shows first drawn object, body
wall outline drawn with Curve tool (A). Upper outline appears curved because
tool used does not produce straight lines. Format AutoShape dialog box is
displayed by right clicking on object and selecting Format AutoShape. New
default Fill and Line color (yellow) is selected, and transparency
slider (B) is adjusted to 80%. Box Default for new objects (C) is checked. D =
zoom box.
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Fig. 3A —PowerPoint (Microsoft) screen shots show refinement of outline of
abdominal wall. Template is visible after fill color is adjusted to
transparent. Anchor points (vertexes) (squares) of object are visible
because Edit Points option is selected. This option can be chosen from Draw
menu or from menu that appears after right clicking on object. Because Curve
tool is used to draw object, upper line segment is curved with bulging of
flanking angled line segments. To change curved segment into straight one,
Straight segment option is selected after right clicking on curved line.
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Fig. 3B —PowerPoint (Microsoft) screen shots show refinement of outline of
abdominal wall. Anchor point (vertex) (straight arrow) at left upper
corner has been changed from Auto to Corner point as described in part 1
[1]. Corner point option can be
selected after right clicking over point in Edit Points mode. Handle of corner
point can be dragged in direction of red curved arrow to adjust curve.
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Fig. 3C —PowerPoint (Microsoft) screen shots show refinement of outline of
abdominal wall. Outcome of body wall outline adjustment. Straight line segment
has been deleted by right clicking on it and selecting Delete Segment. Inner
margin of abdominal cavity (arrow) is drawn in similar manner.
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The following are tips for drawing objects: * Adjusting the
magnification in the Zoom box can help with drawing complex or small objects
(Fig. 2).
- Holding down the Alt key while drawing allows mouse movement in the finer
steps.
- Setting the default filling of objects to transparent allows the user to
continue seeing the template image through the object
(Fig. 2).
- Only the visible parts of partially hidden rear objects need to be
meticulously drawn if the color filling is present and is not transparent.
- Predefined object shapes, such as a rectangle, square, ellipse, circle,
polygon, star, and spiral, are available in the AutoShapes menu and can
facilitate faster composition of the illustration. However, these shapes
cannot be edited with the Edit Points function.
Step 3: Refining the Margins of the Object
Refining or fine-tuning adjusts imperfections in the initial drawing and
helps in drawing detailed outlines. Using high zoom for viewing is recommended
for fine-tuning complex small portions of an illustration. Increase
magnification using the Zoom box, which is located on the standard toolbar
(Fig. 2). It is easier to
refine small details at 200% or even 400% zoom. To refine an object, click the
right mouse button on it and select Edit Points. Drag the points (vertexes) to
the precise location desired. Add points by clicking and then dragging on the
line segment between two points. Delete points (vertexes) by right clicking on
the point and selecting Delete Point. An alternative technique, especially for
deleting more than one point, is to press the Ctrl (control) key and click the
points being deleted. If necessary, change the type of point or line and
finely adjust curves by moving the directional lines (handles) as described in
Figures 3A,
3B,
3C and
4A,
4B and in part 1
[1].
Step 4: Applying Colors and Textures
Customize the outline and fill properties of each object by right clicking
inside an object and selecting Format AutoShape. A dialog box appears. Reveal
color options by clicking on the small arrow next to Color. Fill properties
such as color, uniform or gradient fill, and patterns and textures can be
customized by selecting More Colors and Fill Effects. Transparency can be
defined by sliding the button or changing the percentage in the adjacent box.
Fill settings apply to the area enclosed by the path. Open paths can be filled
as closed paths can. Line properties such as weight (thickness), color, solid
versus dashed, and line caps and corners can be customized by selecting the
appropriate options from the Format AutoShape dialog box
(Fig. 5).
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Fig. 5 —PowerPoint (Microsoft) screen shot shows details of Fill option of
Format AutoShape tool. Gradient effect is selected from Fill Effects option
(A) of drop-down menu that appears after clicking small arrow (B) next to
Color. Intraabdominal fat color is similarly chosen except that Texture rather
than Gradient is selected. After this step, clicking over CT image (template)
and selecting Bring to Front (C) from Order toolbar facilitates drawing of
remaining objects.
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Step 5: Finalizing the Illustration
Steps 2 through 4 can be repeated for the remaining objects to complete the
drawing, or more than one object can be drawn in step 2. After all objects are
drawn, remove the template by right clicking on it and selecting Cut. Make
sure that only the template is selected before clicking Cut. Undo can be used
to reverse any unwanted changes. It is helpful to save frequently, such as
after completing one or more satisfactory steps. Additional details can be
added as needed. Labels can be added with the arrow and text box options of
the Drawing toolbar (Fig. 6A,
6B,
6C,
6D).
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Fig. 6A —PowerPoint (Microsoft) screen shots show finalization of drawing.
Drawing of remaining objects. Hidden portion of renal collecting system does
not need refining. Noncontributory objects have not been included, and
locations of other objects are slightly altered to accommodate drawing of
fascial planes.
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Fig. 6C —PowerPoint (Microsoft) screen shots show finalization of drawing.
After CT image (template) is deleted, first two objects appear. Fascial planes
are drawn as blue lines with Curve tool. Most of these planes are drawn as
open paths (double clicking last point not located over first point). Others
(e.g., line surrounding kidneys) are closed paths. No Fill is selected from
Format AutoShape. Thickness of interfascial planes is exaggerated to show
their potentially expansile nature.
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Fig. 6D —PowerPoint (Microsoft) screen shots show finalization of drawing.
Final drawing after addition of labels. C = colon, P = pancreas, D = duodenum,
IVC = inferior vena cave, Ao = aorta, RK = right kidney, LK = left kidney,
asterisk = posterior peritoneal recess. Retroperitoneal spaces are marked by
drawing transparent objects without applying color to lines or by drawing
dashed lines.
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Because objects are arranged in the drawing as layers, the object added
last is on top. Using the order-changing function is important because drawing
the objects from back to front is not always feasible. For instance, the
transparent color that defines the perinephric space in the example was added
toward the end of the drawing process. After we drew the outline of this
space, we shifted its order to the back. The order of the objects representing
the body wall and the intraabdominal fat then was shifted all the way to the
back with the Send to Back function (see part 1, Fig.
4A,
4B
[1]). The change in order
placed the perinephric space below the kidney but above the abdominal fat.
Similarly, the Bring to Front function moves an object to the front. The Send
Backward and Bring Forward functions change the order of an object only one
step to the back and one step to the front, respectively.
The following are tips for facilitating the drawing of relatively similar
objects:
- Using Copy and Paste is a timesaving technique that allows reuse of objects
from a current or previous drawing. Right click on the object to be copied,
select Copy, right click outside the object, and select Paste. The copied
object can be rotated, flipped, and edited. The left kidney in Figure
6A,
6B,
6C,
6D is a modified copy of the
right. Figure 4A,
4B in Part 1
[1] lists the rotation and
flipping tools.
- To use Copy and Paste with an element composed of multiple objects, the
objects must be grouped. The grouped objects can be selected with a single
click and then moved, resized, and deleted as a single unit with the spatial
relations maintained. The original objects can be separated from one another
by ungrouping. To use grouping, select all the objects by left clicking on the
first object then clicking on the remaining objects while holding down Ctrl.
An alternative is the Select Multiple Objects tool. After selecting the
objects, right click on one of them and select Grouping then Group. To reverse
the grouping, select Ungroup.
- The color and design of similar objects can be changed simultaneously by
selection of these objects before they are formatted.
Step 6: Archiving
One of the advantages of drawing in Power-Point is ease of editing. For
example, an illustration of a particular tumor stage can be simply adjusted to
produce an illustration of a different stage without redrawing all the
elements in the illustration. To facilitate future modification or reuse of
illustrations, save a copy of the slide containing the illustration under a
particular name in a specified folder in addition to saving the file of the
presentation. Instead of searching through entire presentations, it is easier
to find individual illustrated slides that are part of a medical illustration
collection. The collection of illustrations grows into a valuable educational
resource. To make a copy of an individual slide containing an illustration,
right click on the slide thumbnail in the Slide Sorter view (or in the Outline
and Slides tabs on the left side of Normal view). Select Copy from the menu
that appears after the right click. Start a new presentation, right click in
the Outline and Slides tabs, and select Paste. An alternative is to start
drawing the illustration in a new presentation and save it in the collection.
Using the steps just described, copy that slide into the presentation.
Save the copy of the illustration slide using the default presentation file
format (.ppt). This step preserves the vector characteristics of the drawing.
Other types of file format from the Save As dialog box can be used to save
additional copies. For example, tag image file (.tif) format can be used to
save the illustration for publication. In the default setting, the saved image
is 10 x 7.5 inches (25.4 x 19.0 cm) at a resolution of 72 or 96
dots per inch (dpi). Test the computer settings by saving a slide in image
format, right clicking on its icon, and selecting Properties. The details are
displayed when the Summary tab and Advanced buttons are selected. Because most
publishers ask for higher resolution, such as 300 or 600 dpi, additional steps
are needed to meet the requirement.
In the 2003 version of PowerPoint, a registry can be modified to change the
resolution of exported images into 300 dpi
[5,
6]. The image can be reduced to
5 x 3.75 inches (12.7 x 9.5 cm), if necessary, with any image
editing software. This approach is not possible in earlier versions of
PowerPoint.
In PowerPoint for Microsoft XP, enlarge slides by selecting Page Setup from
the File menu and making proportional increases in width and height. Calculate
the degree of enlargement on the basis of the requested size and resolution
using the following formula: approximate enlargement factor = (new resolution
in dpi x new dimension in inches)/(current resolution in dpi x
current dimension in inches). After enlargement, adjust the thickness and
contour of the lines if necessary. After saving the slide in image format, use
image-editing software to change the resolution to the desired value.
Performing the image enlargement step in image-editing software does not
produce results similar to the original owing to degradation in illustration
quality. Resizing in Power-Point does not affect illustration quality, an
advantage of vector drawing. Because the largest available slide dimension in
Microsoft XP PowerPoint is 56 inches (142.2 cm), the highest possible
resolution for a 5-inch (12.7 cm) image is approximately 800 dpi. The same
approach can be used in the 2003 version of PowerPoint. However, the maximum
export resolution is set to a maximum dimension of 3,072 pixels in the 2003
version. Consequently, the highest possible resolution for a 5-inch (12.7 cm)
image is 600 dpi. The maximum resolution values cited are generally sufficient
for publishing halftone colored and gray-scale illustrations. However, higher
resolution, such as 1,200 dpi, is often requested for line drawings.
Conclusion
The drawing tools available in the newer versions of PowerPoint can
facilitate drawing high-quality medical illustrations. Consequently, they can
enhance the educational value of slide presentations. Practicing with the
basic tools described is essential to development of an individual
approach.
Acknowledgments
Microsoft product screen shot(s) are reprinted with permission from
Microsoft Corporation.
References
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AJR 2000; 175:363
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RadioGraphics 2003;23
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- Microsoft Help and Support. How to change the resolution of a slide
that you export as a picture in PowerPoint 2003. Available at:
support.microsoft.com/default.aspx?kbid=827745.
Accessed August 11, 2006
- Yam CS. Using PowerPoint to create high-resolution images for
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Abstract
Introduction
