DOI:10.2214/AJR.05.0454
AJR 2005; 185:1659-1662
© American Roentgen Ray Society
Removing Hidden Patient Data from Digital Images in PowerPoint
Chun-Shan Yam1
1 Department of Radiology, Beth Israel Deaconess Medical Center and Harvard
Medical School, WCC, Room 306, 1 Deaconess Rd., Boston, MA 02215.
Received March 15, 2005;
accepted after revision May 3, 2005.
Address correspondence to C.-S. Yam
(csyam{at}caregroup.harvard.edu).
Abstract
OBJECTIVE. The purpose of this article is to discuss the potential
issue of exposing patient information from digital images used in PowerPoint
presentations.
CONCLUSION. Current methods for safeguarding patient information in
PowerPoint presentations still contain the potential for risk. In radiology,
many digital images used in PowerPoint contain hidden patient identification
information. Although cautious use of cropping and masking techniques has been
adequate for presentation, the hidden information is still available as part
of the digital image and may pose Health Insurance Portability and
Account-ability Act (HIPAA) risks. This article will discuss the origin of
this issue and describe simple solutions for permanently removing patient
information using built-in PowerPoint functions.
Introduction
Recently, I was given a copy of a PowerPoint (Microsoft)
presentation from a radiology colleague at a departmental research meeting as
a contribution to our digital teaching file. Using a plug-and-play external
USB (universal serial bus) storage drive, the PowerPoint presentation was
seamlessly downloaded from my colleague's laptop computer in less than 30 sec.
Back in my office, I used the simple copy-and-paste function to transfer five
images into the PowerPoint teaching file template. On completion, I was
astounded to see the patient's name appear at the top left corner of the last
image.
View larger version (74K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 1 —Screen captures of PowerPoint 2003 (Microsoft) showing
process steps for exporting all slides to bitmap images. In this example, 51
images (i.e., slide01.bmp, slide02.bmp, etc.) are exported to desktop folder
named Output. Other picture formats such as PNG and JPG can also be used in
this process.
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I switched back to the original presentation and looked at the image again.
There was no patient's name on the image. Perplexed, I repeated the same
copy-and-paste function only to find the same result. Finally, this mystery
was solved when I moved the image slightly away from its original position.
The patient's name was exposed; it had been masked by a small rectangular box
(a PowerPoint Drawing Object filled with black). Further examination of the
other four copied images revealed that three had patients' names and
identification hidden in the cropped areas. For these three images, the
patients' information did not display immediately after the images were pasted
to my computer, but only after I used the Picture Crop tool to reset the
images to the original dimensions.
View larger version (65K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 2 —Screen captures of PowerPoint 2003 (Microsoft) showing use of
Photo Album function to create new presentation from individual
images—in this example, same 51 images exported from
Figure 1 as source images.
Select Fit to Slide option to preserve original dimensions. Click Create
button to generate new presentation.
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Subsequently, I shared these two findings with my colleague who fortunately
had the chance to correct the images before submitting the PowerPoint
presentation for an online education exhibit at the 2004 annual Radiological
Society of North America meeting. Although many radiologists currently use
these two common methods (i.e., masking and cropping) to hide patient
information printed on digital images, the issue of reversing these methods to
expose confidential data is not commonly known. In this article, I describe
two solutions for this potentially sensitive HIPAA issue
[1].
Solution 1: Global Conversion
In PowerPoint, the unwanted image pixels (i.e., patient information)
resulting from the masking and cropping techniques are still present in the
original images. PowerPoint does not erase or discard these pixels—they
are simply made invisible during the presentation
[2]. However, there is an easy
solution for removing the unwanted pixels permanently.
Step 1: Export all the slides to individual images
(Fig. 1). Use the Save As
function to export all the PowerPoint slides as individual images.
Step 2: Create a new presentation from the exported images
(Fig. 2). Use the Photo Album
function to automatically insert all the exported images back into PowerPoint
as a new presentation.
In this process, the exported images are converted from screen shots of
each slide in the PowerPoint presentation. Thus, they no longer contain any
hidden pixels or invisible objects. Although this solution is easy to use and
ensures permanent removal of hidden patient information, there are some
drawbacks. The converted presentation is view only; it will not allow further
text editing, and all slide transitions and animations will be lost. However,
some image editing functions, such as contrast and brightness, can still be
applied to slides containing only images. Also, if the original presentation
contains movie clips, these movie clips will need to be reinserted into the
new presentation. One easy way to preserve the original text-only slides is to
replace them with the original slides after the conversion process using the
copy-and-paste function between the two presentations.
View larger version (41K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 3 —Screen captures of PowerPoint 2003 (Microsoft) using Compress
Pictures function to eliminate cropped areas from all digital images within
presentation. Also, selecting both Web/Screen and Compress Pictures options
will optimize file size for presentation. Function can also be used in
solution 1 to reduce file size after global conversion.
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Many radiologists in our department find this solution acceptable,
particularly for simple presentations containing only images and text. For
other experienced PowerPoint users who prefer using complex PowerPoint
features (e.g., transitions, animations, hyper-links, and objects), a more
flexible solution may be needed. The next solution will describe another
approach for removing patient information from digital images while preserving
other features and objects.
Solution 2: Individual Image Modification
To preserve other PowerPoint features and objects, digital images must be
processed separately.
Patient Data Hidden in Cropped Images
To eliminate patient information hidden in cropped image areas (Note:
PowerPoint does not erase these unwanted pixels), use the built-in Compress
Pictures function in PowerPoint 2002 or 2003. Although the use of this
function has been documented for reducing file size
[3], it is not well known for
erasing pixels. Begin by selecting any one image from the presentation and
then select the Compress Pictures function from the Picture Toolbar
(Fig. 3). In the Compress
Pictures window, select both options for All Pictures in Document and Delete
Cropped Areas of Pictures; and then click the OK button. Next, click the Apply
button to start the compression process. Using this approach, patient
information hidden in the cropped areas of all images will be eliminated
permanently. A step-by-step illustration for this process is provided in
Figure 3.
Patient Data Masked by Other Drawing Objects
Currently, in PowerPoint, there is no tool to remove the unwanted image
pixels from digital images. Alternatively, radiologists use rectangular boxes
(Drawing Objects) to mask the patient information
[3]. However, as explained
previously, this approach is not adequate to safeguard the patient
information. To avoid this issue, the unwanted pixels must be eliminated using
other image processing software such as Adobe Photoshop
[4], Corel Draw, or Microsoft
Paint before using the images in PowerPoint. However, if the images are
already inserted into PowerPoint with Drawing Objects placed to mask the
patient information, there is an easy solution.
Step 1: In the PowerPoint slide, select both the image and the
Drawing Object(s).
Step 2: Use the Save as Picture function to save the selected
items as a picture (Fig.
4).
View larger version (31K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 4 —Screen captures showing use of Save as Picture function to
eliminate hidden patient information. First, select three overlaying
rectangles and background CT image using simple click-and-drag action. Then,
click (right mouse) on selected items to bring up pop-up menu. In this menu,
click on Save as Picture function and save items as PNG pictures on desktop.
Next, delete selected items from PowerPoint slide and reinsert PNG picture
back into slide using drag-and-drop.
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Step 3: Delete the original items from the PowerPoint slide.
Step 4: Insert the picture back into PowerPoint using
drag-and-drop.
Figure 4 shows an example
for Steps 1 and 2 of this process using PowerPoint 2003 in Windows XP and
Microsoft Paint in Windows XP Professional (Microsoft). This Save as Picture
function is available in most PowerPoint versions (i.e., 2000, XP, and 2003
for the PC; and 2004 for the Macintosh [Apple Computer]).
Alternatives
Although the two solutions presented in this article are easy to use and do
not require any other software besides PowerPoint, other alternatives may be
feasible. For example, editing the screen capture of the PowerPoint slides in
other image processing software (e.g., Photoshop or Paint) can also achieve
the same results.
Limitations
The Photo Album function is available in PowerPoint 2002 and 2003 only and
is an optional feature in PowerPoint 2000. The Compress Pictures function is
only available in PowerPoint 2002 and 2003. Neither of these PowerPoint
functions is available on Macintosh versions.
The solutions described in this article are most appropriate for
nonclinical applications. Based on my experience, some radiologists use
PowerPoint presentations for clinical patient follow-up where patient
information is necessary for diagnosis and care. In such situations, I suggest
using a simple encryption tool such as WinZip (WinZip Computing) to encrypt
and apply password protection to the presentation file before any electronic
transmission. Currently, WinZip can be used for free, unlimited evaluation
(www.winzip.com).
The installation of WinZip is straightforward.
Conclusion
Current methods for safeguarding patient information in PowerPoint
presentations still contain the potential for risk. In radiology, many digital
images used in PowerPoint contain hidden patient identification information.
Although cautious use of cropping and masking techniques has been adequate for
presentation, the hidden information is still available as part of the digital
image and may pose HIPAA risks
[1]. This article has discussed
the origin of this issue and described simple solutions for permanently
removing patient information using built-in PowerPoint functions. However, the
best approach is to obtain the source images without annotations during the
image capturing process from PACS workstations or desktop DICOM viewers. This
can eliminate the problem from the outset.
References
- Joint Healthcare Information Technology Alliance. Conference
proceedings: charting a course—HIPAA implementation. In:
HIPAA: the facts you need for compliance. Chicago, IL:
Joint Healthcare Information Technology Alliance,2000
- Schreibman KL. Getting images into PowerPoint.
AJR 2001; 177:1271
-1272[Free Full Text]
- Lababede O. Digital image editing using PowerPoint. 1. Introduction
to the image-manipulation commands. AJR2004; 183:847
-851[Abstract/Free Full Text]
- Stern EJ, Richardson ML. Preparation of digital images for
presentation and publication. AJR 2003;180
: 1523-1531[Free Full Text]
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Abstract
Introduction
