Hologic R2 ImageChecker User manual

Understanding

R2 ImageChecker

Software Versions 8.5– 8.7

MAN-01049 Rev 001

®

Screen-Film Mammography

Understanding

R2 ImageChecker

Software Versions 8.5–8.7

PN MAN-01049 Rev 001

®

Technical Support

For support in North America contact:

Toll Free: +1 866.243.2533 (866.CHECKED)
Email: [e-mail]
Hours: Monday – Friday, 6:00 AM – 5:00 PM, PT (GMT –8:00)
Website: www.hologic.com

For support in Europe, South America, or Asia, contact your local dealer or distributor.

© 2008, Hologic, Inc. All rights reserved. Duplication or distribution without written permission
is prohibited. Hologic reserves the right to revise this manual. Issued August 2008.

Protected by one or more of the following U.S. Patents: 5133020, 5452367, 5491627, 5537485,
5622171, 5657362, 5673332, 5729620, 5732697, 5740268, 5815591, 5828774, 5832103,
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7054473, 7072498, 7146031, 7174515

Hologic, the Hologic logo, Cenova, CheckMate, DigitalNow, EmphaSize, ImageChecker, Malc,
Mammolux, R2, R2 Technology, SecurView
trademarks of Hologic in the USA. MergeCOM-3 is a trademark of Merge Healthcare.

, and Selenia are trademarks or registered

DX

Hologic Inc.
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Bedford, MA 01730-1401 USA
Tel: [phone]
Sales: +1.781.999.7453
Fax: [phone]

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Tel: [phone]

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Authorized Representative
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Tel: [phone]
Fax: [phone]

MergeCOM-3 Advanced Integrator’s
Tool Kit is a product of Merge
Healthcare.

ii Understanding R2 ImageChecker 8.5–8.7 – PN MAN-01049 Rev 001

Contents

Part 1: Introduction....................................................... 1

1.1. Intended Use......................................................... 1

1.2. Resources Available ................................................... 2

1.3. Warnings and Precautions .............................................. 3

1.4. Overview of ImageChecker CAD.......................................... 5

1.5. Benefits of ImageChecker CAD........................................... 6

1.6. Devices Used with ImageChecker CAD .................................... 7

1.7. ImageChecker Features ................................................ 8

RightOn CAD Marks................................................... 8

EmphaSize........................................................... 8

PeerView and PeerView Digital ........................................... 8

Operating Points ...................................................... 9

Part 2: Data Inputs and Outputs ......................................... 11

2.1. Film-Based CAD with DigitalNow........................................ 11

2.2. CAD Inputs and Supported Views ....................................... 13

View Modifiers ...................................................... 14

Images with Breast Implants ............................................ 14

2.3. Image and Case Processing ............................................ 15

Selecting Images for Case Processing ...................................... 16

2.4. System Outputs ..................................................... 18

CAD Results Report .................................................. 19

Part 3: Algorithm Description ............................................ 21

3.1. ImageChecker CAD Algorithm .......................................... 21

3.2. RightOn CAD Marks .................................................. 22

Limiting the Number of Marks .......................................... 22

3.3. EmphaSize Marks .................................................... 23

3.4. PeerView and PeerView Digital ......................................... 24

3.5. What the Algorithm Detects............................................ 25

Calcifications........................................................ 25

Masses/Architectural Distortions......................................... 26

Understanding R2 ImageChecker 8.5–8.7 – PN MAN-01049 Rev 001 iii

Contents

3.6. Detecting Calcifications ............................................... 28

Image Processing for Calcifications ....................................... 28

Case Processing for Calcifications ........................................ 29

3.7. Detecting Masses .................................................... 30

Image Processing for Masses ............................................ 30

Case Processing for Masses ............................................. 31

3.8. CAD Operating Points................................................. 32

Index .................................................................. 35

iv Understanding R2 ImageChecker 8.5–8.7 – PN MAN-01049 Rev 001

Part 1: Introduction

f 1.1. Intended Use
f

1.2. Resources Available

f

1.3. Warnings and Precautions

f

1.4. Overview of ImageChecker CAD

f

1.5. Benefits of ImageChecker CAD

f

1.6. Devices Used with ImageChecker CAD

f

1.7. ImageChecker Features

R2 ImageChecker® is a software application used for analyzing mammography
images. This manual describes R2 ImageChecker software versions 8.5, 8.6, and 8.7,
which were developed to provide the ImageChecker software as a licensed option
with these Hologic film scanning systems:

• R2 DMax System

• R2 LS System

• R2 DM System

These systems support a second application, R2 DigitalNow™, which the systems use
to create archivable digital mammography image files from the original films.

R2 ImageChecker 8.7 is available as a software upgrade for customers that have
previous versions. For customers using full-field digital mammography (FFDM)
systems, the ImageChecker software is also available as a licensed option with
Hologic’s R2 Cenova digital mammography server. For more information, contact
your Hologic customer representative.

The information in this manual is intended to serve as a reference for radiologists and
clinic personnel who need to understand how ImageChecker computer-aided
detection (CAD) can be integrated into their practice.

1.1. Intended Use

ImageChecker is a software application intended to identify and mark regions of
interest on routine screening and diagnostic mammograms to bring them to the
attention of the radiologist after the initial reading has been completed.
ImageChecker assists the radiologist in minimizing observational oversights by
identifying areas on the original mammogram that may warrant a second review.

Understanding R2 ImageChecker 8.5–8.7 – PN MAN-01049 Rev 001 1

Part 1: Introduction

1.2. Resources Available

In addition to this manual, the following resources are available to assist you:

•

R2 Member Center: This website provides quick access to electronic (pdf) versions

of Hologic manuals and training materials. You can find the R2 Member Center by
visiting the Hologic website (
accompanies this product for instructions on accessing the R2 Member Center.

•

Manuals: The manuals for the R2 film scanning systems are listed below:

– Understanding R2 ImageChecker

– R2 DMax User Manual

– R2 DM User Manual

– R2 LS User Manual

– R2 DMax/DM/DX/LS Service Manual

– R2 DMax/DM/DX/LS Release Notes

– R2 DMax/DM/DX/LS DICOM Conformance Statement

You can obtain additional copies of printed manuals through your Hologic
Account Manager. The DICOM Conformance Statement is available at

www.hologic.com.

www.hologic.com). See the R2U flyer that

•

Training: The Hologic Applications team is available to train your staff, should you

feel they need additional training. To purchase additional personalized instruction,
contact your Hologic Account Manager.

•

Technical Support and Service: For support in North America contact:

Toll Free: +1.866.243.2533 (+1.866.CHECKED)

Email: [e-mail]

Hours: Monday – Friday, 6:00 AM – 5:00 PM, PT (GMT –8:00)

Website: www.hologic.com

For support in Europe, South America, or Asia, contact your local dealer or
distributor.

2 Understanding R2 ImageChecker 8.5–8.7 – PN MAN-01049 Rev 001

1.3. Warnings and Precautions

 Note: For Warnings and Cautions related to the installation, operation, and

maintenance of the R2 film scanning system, refer to the user manual accompanying the
product.

• The radiologist should base interpretation only on original diagnostic-quality

images and not depend on ImageChecker CAD marks for interpretation.



• The device is a detection aid, not an interpretative aid. ImageChecker CAD marks

should be activated only after the first reading.

• The device does not enhance what the user sees; rather it helps to identify regions

on mammograms that should be re-examined.

• The ImageChecker software marks calcification features with triangles (Calc

marks) and mass features with asterisks (Mass marks). The software marks mass
and calcification features that occur at the same location on the image with
pointed crosses (Malc marks). These features may not represent cancer, and the
skill of the user is still required for proper interpretation of the marked areas.

• EmphaSize (variable-size) marks – Sites may choose to display prominence detail,

in which case the size of a Calc, Mass, or Malc mark is proportional to the ranking
of the feature by the algorithm. The marked features may not represent cancer,
and the skill of the user is still required for proper interpretation of areas marked
by the device.

1.3. Warnings and Precautions

• For proper system operation, the technical quality of the original films or images

(e.g., contrast) should meet relevant MQSA standards (or the appropriate national
standards) and be acceptable to the mammographer.

• The use of digitized images (scanned film images) for primary reading has not

been approved by MQSA. Digitized film images retrieved from archive should be
used only for the purpose of comparison with digital images meeting the current
standard.

• During routine interpretation of mammograms and results produced by

ImageChecker CAD, Hologic recommends use of a mammography workstation
that has been FDA-approved, recently calibrated, and employs a CAD marking
schema authorized by Hologic.

• ImageChecker software does not identify all areas that are suspicious for cancer.

– The software does not mark all lesions and a user should not be dissuaded from
working up a finding if the software fails to mark that site.

– The software is not designed to detect changes from prior mammograms.

– The software is not designed to detect skin thickening or nipple retractions.

– Conditions of the breast that diminish mammographic sensitivity, such as
density of normal tissue, also diminish the sensitivity of the software.

– The software is more sensitive for detection of calcifications than masses, and the
sensitivity depends on the site-specific operating points chosen. For sensitivity
values, see ‘
algorithm has a lower sensitivity for masses greater than 2.5 cm in diameter.

3.8. CAD Operating Points’. In addition to not marking all masses, the

Understanding R2 ImageChecker 8.5–8.7 – PN MAN-01049 Rev 001 3

Part 1: Introduction

– Individual practice patterns may influence results obtained when using
ImageChecker CAD. Therefore, each facility and radiologist should carefully
monitor the results that the software has on their practice of mammography in
order to optimize its effectiveness.

• The performance of the system has not been characterized for mammograms from

patients with:

– Breast implants. Process only Implant-Displaced Views with less than 2.5 cm (1
in) of the breast implant appearing on the image.

– Special diagnostic views (e.g., magnified views or spot-compressed views).
Process only full-view diagnostic images.

– Segmented views of the breast (e.g., ‘mosaic’ views) with no clear breast border.
Process only views with breast borders.

4 Understanding R2 ImageChecker 8.5–8.7 – PN MAN-01049 Rev 001

1.4. Overview of ImageChecker CAD

Systems configured with R2 ImageChecker 8.5–8.7 analyze digitized film
mammography images with a software algorithm that identifies regions of interest,
which can include clusters of bright spots (suggestive of calcification clusters), and
dense regions with or without radiating lines (suggestive of masses or architectural
distortions). The systems generate results that include ImageChecker CAD marks
identifying the regions of interest. The results produced are either image files,
Mammography CAD SR (Structured Report) objects, or both.

After making an initial interpretation from the original mammograms, the radiologist
displays the ImageChecker results and chooses whether or not to reinspect the
marked regions on the original mammogram. The ImageChecker algorithm marks
visually perceptible structures that have some of the generally accepted geometric
characteristics of calcifications or masses. The marked areas may be something other
than an actual abnormality, which the radiologist generally recognizes upon a second
review of the original mammogram.

1.4. Overview of ImageChecker CAD

Examination is

Performed

Films

CAD Results

ImageChecker

Analyzes the Images

ImageChecker Workflow

Radiologist

Reviews Films

and CAD Results

Understanding R2 ImageChecker 8.5–8.7 – PN MAN-01049 Rev 001 5

Part 1: Introduction

1.5. Benefits of ImageChecker CAD

The interpretation of mammograms is challenging. Normal breast tissue varies widely
among women, even for the same woman over time or at different times of the
month. The radiologist also has to balance the need for accurate detection of breast
cancer with the need to limit the number of unnecessary procedures. The
combination of viewing a large number of cases, radiologist fatigue, the complex
image of the breast structure, and the subtle nature of certain observable
characteristics of the disease can result in false-negative readings. In fact, studies show
that half of undetected cancers are missed due to observational oversights. The
prevalence of observational oversights is not strongly related to experience and may
be inevitable with human observers.

R2 ImageChecker functions like a spellchecker for medical images. It is designed to
help radiologists in reducing the number of false-negative readings due to
observational oversight by drawing their attention to areas that may warrant a second
review. Use of ImageChecker CAD can result in earlier detection of up to 23.4% of
the cancers currently detected with screening mammography in those women who
had a prior screening mammogram 9–24 months earlier. Early detection is the key to
higher survival rates, better prognosis, and lower treatment costs.

6 Understanding R2 ImageChecker 8.5–8.7 – PN MAN-01049 Rev 001

1.6. Devices Used with ImageChecker CAD

All systems with R2 ImageChecker 8.5–8.7 include a film scanner for scanning
mammography X-ray films and a processing unit computer configured with the R2
image-processing software. There are three models:

• R2 DMax System

• R2 LS System

• R2 DM System

Facilities must also have an output device in order to review or store the CAD results.
These devices may include any of the following:

• R2 CheckMate Ultra™ display unit

• Postscript printer

1.6. Devices Used with ImageChecker CAD

• Diagnostic mammography review workstation (such as Hologic’s SecurView

dx

)

• PACS (Picture Archiving and Communication System)

The system devices are connected by a computer network and can be in the same
room, different rooms, the same building, different buildings, or even different cities.
The R2 processing unit can send results to several different output devices.

The R2 DMax, LS, and DM systems are designed to:

• Scan mammography X-ray films and convert them into digital image files

• Allow users to review the scanned images, and to reorient, label, and reprocess the

images as needed.

• Analyze the images using the R2 ImageChecker algorithm to detect regions of

interest.

• Transmit the study results so they can be viewed on an output device such as the

R2 CheckMate Ultra display unit, printer, diagnostic review workstation (or to a
PACS for archiving).

Understanding R2 ImageChecker 8.5–8.7 – PN MAN-01049 Rev 001 7

Part 1: Introduction

1.7. ImageChecker Features

R2 ImageChecker provides the following features, which are discussed below:

f RightOn CAD Marks
f

EmphaSize

f

PeerView and PeerView Digital

f

Operating Points

Upon installation, the Hologic field service engineer will configure the software based
on the preferences of site personnel. Thereafter, your Hologic representative can help
you add a new license (such as DigitalNow) and enable or disable features as needed.

For more information on ImageChecker features, see ‘

 Important! Display of results from each ImageChecker feature depends upon several

factors, in particular:

• The feature must be licensed and enabled on the R2 processing unit.

• The review workstation must be equipped with software that can interpret the output

produced by the processing unit.

Some workstations can interpret only a subset of ImageChecker features. Consult with
your workstation vendor concerning availability and integration of ImageChecker features
with your workstation.

RightOn CAD Marks

The ImageChecker software provides three types of RightOn™ CAD marks (Mass,
Calc, and Malc) that can appear in the results. You can choose to display any or all of
the three types of marks. Each mark identifies a region of interest for the radiologist
to review.

Part 3: Algorithm Description’.

Calc – Marks regions suggestive of calcifications.

Mass – Marks regions suggestive of masses or architectural distortions.

Malc – Marks regions where Calc and Mass marks are coincident.

EmphaSize

The processing unit is configured by default to convert the CAD marks to
EmphaSize™ marks, which can be viewed on some diagnostic review workstations, as
well as the R2 output devices (R2 CheckMate Ultra and postscript printer).
EmphaSize produces CAD marks of variable size that correlate to feature significance.
When the algorithm determines that a region is more significant, the CAD mark
appears larger, indicating that the region should receive more emphasis from the
radiologist. EmphaSize marks can be disabled if clinic staff choose not to use them.
For more information see ‘

3.3. EmphaSize Marks’.

PeerView and PeerView Digital

PeerView™ and PeerView Digital are optional features that help radiologists better
understand why a region of interest was marked. PeerView and PeerView Digital

8 Understanding R2 ImageChecker 8.5–8.7 – PN MAN-01049 Rev 001