(304 days)
Not Listed
Yes
The device description explicitly states that it "utilizes machine learning algorithms".
No
The device is a computer-aided detection (CADe) tool that identifies potential lung nodules and masses on chest radiographs to aid physician interpretation, but it is not intended to replace the physician's review or make diagnoses. It does not directly treat or prevent a medical condition.
Yes
This device is a computer-aided detection (CADe) device intended to identify and mark regions of interest that may be suspicious for lung nodules and masses on chest radiographs. While it does not make a final diagnosis, it aids the physician in their interpretation by identifying suspicious findings, which is a diagnostic function.
Yes
The device is explicitly described as "software as a medical device (SaMD) product" and its function is solely based on processing digital images (DICOM) and outputting annotated digital images. There is no mention of any associated hardware component that is part of the medical device itself.
Based on the provided information, this device is not an IVD (In Vitro Diagnostic).
Here's why:
- IVD definition: In vitro diagnostics are tests performed on samples taken from the human body, such as blood, urine, or tissue, to detect diseases, conditions, or infections.
- VisiRad XR's function: VisiRad XR analyzes medical images (chest radiographs), not biological samples. It's a software that processes existing images to aid in the interpretation of those images.
Therefore, VisiRad XR falls under the category of medical imaging software or a computer-aided detection (CADe) device, not an in vitro diagnostic device.
No
The letter does not state that the FDA has reviewed and approved or cleared a Predetermined Change Control Plan (PCCP) for this specific device.
Intended Use / Indications for Use
VisiRad XR is a computer-aided detection (CADe) device intended to identify and mark regions of interest that may be suspicious for lung nodules and masses on chest radiographs. It identifies features associated with pulmonary nodules and masses from 6-60mm in size. Detection of suspicious findings by VisiRad XR is intended as an aid only after the physician has performed an initial interpretation; it is not intended to replace the review by a qualified radiologist and is not intended to be used for trage or to make or confirm a diagnosis. The intended patient population for VisRad XR consists of patients >21 years of age on whom chest radiographs have been acquired in an outpatient or emergency department setting.
Product codes
MYN
Device Description
VisiRad XR is a computer aided detection (CADe) software as a medical device (SaMD) product intended to detect lung nodules and masses from 6-60mm in chest radiographs. VisiRad XR takes DICOM images as input, utilizes machine learning algorithms to detect suspicious regions and outputs a secondary DICOM with annotated regions of interest (ROIs).
VisiRad XR's output secondary DICOM includes text that it was analyzed by VisiRad XR and a link to the user manual. If no ROIs are detected by VisiRad XR, the returned secondary DICOM states "No Nodules/Masses Found".
VisiRad XR is intended to be used as a second-read only after the clinician has performed their initial interpretation. The secondary DICOM does not overwrite or replace the primary radiograph, it is returned such that it hangs, using standard DICOM hanging protocol, behind the primary image.
Mentions image processing
Yes
Mentions AI, DNN, or ML
Yes
Input Imaging Modality
X-ray
Anatomical Site
Chest / Lung
Indicated Patient Age Range
21 years of age
Intended User / Care Setting
Physician, outpatient or emergency department setting.
Description of the training set, sample size, data source, and annotation protocol
Not Found
Description of the test set, sample size, data source, and annotation protocol
Standalone performance test dataset:
Data from three sources: National Lung Screening Trials (NLST) and two independent data sites. NLST is a high-quality, outpatient dataset that enrolled current or former heavy smokers. The two independent sites were a Level II trauma center at a rural group practice in Montana and a Level I trauma center in a metropolitan area of Colorado. Data was acquired from each site's emergency department between 2016 and 2021.
Clinical Performance Testing: MRMC Study
600 total patient images (300 per site) from across the United States (data collection sites included Colorado, Ohio, New Jersey, South Carolina, Iowa and Wisconsin). The subject population was composed of patients who represent the range of age, racial and ethnic groups and geographic diversity that are representative of the intended use population. Women made up 56% of the study; of the population that disclosed racial data, 47% of the patient population identified as a racial group other than white or Caucasian. Readers interpreted the same radiograph twice in a row, first unaided then aided by VisiRad XR. They were asked to interpret the radiographs as they would in standard clinical practice and note nodules or masses with a bounding box and associated level of confidence in their interpretation. The study compared unaided and aided radiologist performance at detecting pulmonary nodules and masses as compared to the reference standard.
Summary of Performance Studies
Standalone performance test:
The primary endpoint was device sensitivity calculated at an image level. The study was executed at a fixed operating threshold.
Study results demonstrated an overall sensitivity of 0.83 (95% Cl: 0.81-0.84) with average false positives per image of 1.5.
Device performance was stratified across multiple subgroups (age, gender, race, hardware used). Device performance remains consistent between gender, age groups and hardware type used.
Area Under the Curve (AUC) of the Receiver Operating Characteristic (ROC) curve was assessed as a secondary endpoint. Overall AUC, calculated non-parametrically, was 0.73 (95% Cl: 0.71-0.74).
Clinical Performance Testing: Multi-Reader, Multi-Case (MRMC) retrospective reader study
Sample size: 24 clinical readers (12 per site) and 600 total patient images (300 per site).
Primary objective: to determine whether the accuracy of readers aided by VisiRad XR was superior to the accuracy of readers unaided by VisiRad XR as determined by the image-level Area Under the Curve (AUC) of the Receiver Operating Characteristic (ROC) curve.
For both sites, the use of VisiRad XR improved readers' AUC with statistical significance. Mean AUCs for the two conditions calculated across all readers were compared using a two-sided test at the alpha=0.05 level of significance with a p value
§ 892.2070 Medical image analyzer.
(a)
Identification. Medical image analyzers, including computer-assisted/aided detection (CADe) devices for mammography breast cancer, ultrasound breast lesions, radiograph lung nodules, and radiograph dental caries detection, is a prescription device that is intended to identify, mark, highlight, or in any other manner direct the clinicians' attention to portions of a radiology image that may reveal abnormalities during interpretation of patient radiology images by the clinicians. This device incorporates pattern recognition and data analysis capabilities and operates on previously acquired medical images. This device is not intended to replace the review by a qualified radiologist, and is not intended to be used for triage, or to recommend diagnosis.(b)
Classification. Class II (special controls). The special controls for this device are:(1) Design verification and validation must include:
(i) A detailed description of the image analysis algorithms including a description of the algorithm inputs and outputs, each major component or block, and algorithm limitations.
(ii) A detailed description of pre-specified performance testing methods and dataset(s) used to assess whether the device will improve reader performance as intended and to characterize the standalone device performance. Performance testing includes one or more standalone tests, side-by-side comparisons, or a reader study, as applicable.
(iii) Results from performance testing that demonstrate that the device improves reader performance in the intended use population when used in accordance with the instructions for use. The performance assessment must be based on appropriate diagnostic accuracy measures (
e.g., receiver operator characteristic plot, sensitivity, specificity, predictive value, and diagnostic likelihood ratio). The test dataset must contain a sufficient number of cases from important cohorts (e.g., subsets defined by clinically relevant confounders, effect modifiers, concomitant diseases, and subsets defined by image acquisition characteristics) such that the performance estimates and confidence intervals of the device for these individual subsets can be characterized for the intended use population and imaging equipment.(iv) Appropriate software documentation (
e.g., device hazard analysis; software requirements specification document; software design specification document; traceability analysis; description of verification and validation activities including system level test protocol, pass/fail criteria, and results; and cybersecurity).(2) Labeling must include the following:
(i) A detailed description of the patient population for which the device is indicated for use.
(ii) A detailed description of the intended reading protocol.
(iii) A detailed description of the intended user and user training that addresses appropriate reading protocols for the device.
(iv) A detailed description of the device inputs and outputs.
(v) A detailed description of compatible imaging hardware and imaging protocols.
(vi) Discussion of warnings, precautions, and limitations must include situations in which the device may fail or may not operate at its expected performance level (
e.g., poor image quality or for certain subpopulations), as applicable.(vii) Device operating instructions.
(viii) A detailed summary of the performance testing, including: test methods, dataset characteristics, results, and a summary of sub-analyses on case distributions stratified by relevant confounders, such as lesion and organ characteristics, disease stages, and imaging equipment.
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Image /page/0/Picture/0 description: The image contains the logo of the U.S. Food and Drug Administration (FDA). The logo consists of two parts: the Department of Health & Human Services logo on the left and the FDA logo on the right. The FDA logo features the letters 'FDA' in a blue square, followed by the words 'U.S. FOOD & DRUG ADMINISTRATION' in blue text.
August 3, 2023
Imidex Inc. % Kris Zeschin Chief Operating Officer 3513 Brighton Blvd., Suites 456 7 454 DENVER, CO 80216
Re: K223133
Trade/Device Name: VisiRad XR Regulation Number: 21 CFR 892.2070 Regulation Name: Medical Image Analyzer Regulatory Class: Class II Product Code: MYN Dated: July 3. 2023 Received: July 3, 2023
Dear Kris Zeschin:
We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database located at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.
Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's
1
requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801); medical device reporting of medical device-related adverse events) (21 CFR 803) for devices or postmarketing safety reporting (21 CFR 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reportingcombination-products); good manufacturing practice requirements as set forth in the quality systems (OS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.
Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to https://www.fda.gov/medical-device-safety/medical-device-reportingmdr-how-report-medical-device-problems.
For comprehensive regulatory information about mediation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medicaldevices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-device-advice-comprehensive-regulatoryassistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).
Sincerely,
Lu Jiang
Lu Jiang, Ph.D. Assistant Director Diagnostic X-Ray Systems Team DHT8B: Division of Imaging Devices and Electronic Products OHT8: Office of Radiological Health Office of Product Evaluation and Quality Center for Devices and Radiological Health
Enclosure
2
Indications for Use
510(k) Number (if known) K223133
Device Name VisiRad XR
Indications for Use (Describe)
VisiRad XR is a computer-aided detection (CADe) device intended to identify and mark regions of interest that may be suspicious for lung nodules and masses on chest radiographs. It identifies features associated with pulmonary nodules and masses from 6-60mm in size. Detection of suspicious findings by VisiRad XR is intended as an aid only after the physician has performed an initial interpretation; it is not intended to replace the review by a qualified radiologist and is not intended to be used for trage or to make or confirm a diagnosis. The intended patient population for VisRad XR consists of patients >21 years of age on whom chest radiographs have been acquired in an outpatient or emergency department setting.
| Type of Use (Select one or both, as applicable) | |
|---|---|
| ------------------------------------------------- | -- |
|X Prescription Use (Part 21 CFR 801 Subpart D)
| | Over-The-Counter Use (21 CFR 801 Subpart C)
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Image /page/3/Picture/0 description: The image shows the word "IMIDEX" in blue font. To the left of the word is a graphic of a Lorenz attractor, which is a 3D structure that exhibits chaotic flow. The attractor is colored with a gradient from red to orange.
K223133 Section 05: 510(k) Summary
Section 5: 510(k) Summary
Applicant Name and Address 1
Name: IMIDEX, Inc.
3513 Brighton Blvd #456 Address: Denver, CO 80216
Official Contact: Kris Zeschin, Chief Operating Officer
- Summary Preparation Date: September 29, 2022 2
3 Device Name and Classification
VisiRad XR Trade Name: Common Name: Medical image analyzer Classification Name: Medical image analyzer Device Classification: Class II, 21 CFR 892.2070 Product Code: MYN
4 Predicate Device
Name: Samsung Auto Lung Nodule Detection, K201560 Device Classification: Class II, 21 CFR 892.2070 Product Code: MYN
5 Device Description
- VisiRad XR is a computer aided detection (CADe) software as a medical device (SaMD) product 5.1 intended to detect lung nodules and masses from 6-60mm in chest radiographs. VisiRad XR takes DICOM images as input, utilizes machine learning algorithms to detect suspicious regions and outputs a secondary DICOM with annotated regions of interest (ROIs).
- 5.2 VisiRad XR's output secondary DICOM includes text that it was analyzed by VisiRad XR and a link to the user manual. If no ROIs are detected by VisiRad XR, the returned secondary DICOM states "No Nodules/Masses Found".
- 5.3 VisiRad XR is intended to be used as a second-read only after the clinician has performed their initial interpretation. The secondary DICOM does not overwrite or replace the primary radiograph, it is returned such that it hangs, using standard DICOM hanging protocol, behind the primary image.
6 Intended Use
- 6.1 VisiRad XR is intended to identify and mark regions of interest suspicious for lung nodules and masses on chest radiographs.
7 Indications for Use
- 7.1 VisiRad XR is a computer-aided detection (CADe) device intended to identify and mark regions of interest that may be suspicious for lung nodules and masses on chest radiographs. It identifies features associated with pulmonary nodules and masses from 6-60mm in size. Detection of suspicious findings by VisiRad XR is intended as an aid only after the physician has performed an initial interpretation; it is not intended to replace the review by a qualified radiologist and is not intended to be used for triage or to make or confirm a diagnosis. The intended patient population for VisiRad XR consists of patients >21 years of age on whom chest radiographs have been acquired in an outpatient or emergency department setting.
- 8 Substantial Equivalence
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Image /page/4/Picture/0 description: The image shows the word "IMIDEX" in a sans-serif font, with the letters in a dark blue color. To the left of the word is a complex, swirling design in shades of red and orange. The design appears to be a mathematical representation of a chaotic system, possibly a Lorenz attractor.
- 8.1 VisiRad XR has the same intended use as the predicate device. Differences in indications for use do not constitute a new intended use and differences in technological characteristics do not raise new questions of safety and effectiveness.
| Proposed Device | Predicate Device | |
|---|---|---|
| Device Name | VisiRad XR | AutoLung Nodule Detection (ALND) |
| Manufacturer | IMIDEX, Inc. | Samsung Electronics |
| 510(k) Number | -- | K201560 |
| Classification | ||
| Regulation | 21 CFR 892.2070 | 21 CFR 892.2070 |
| Product Code | MYN | MYN |
| Intended Use | VisiRad XR is intended to | |
| to identify and mark regions of | ||
| interest suspicious for lung nodules | ||
| and masses on chest radiographs. | The Auto Lung Nodule Detection is | |
| computer-aided detection software to | ||
| identify and mark regions in relation to | ||
| suspected pulmonary nodules from 10 | ||
| to 30 mm in size. | ||
| Indications for Use | VisiRad XR is a computer-aided | |
| detection (CADe) device intended to | ||
| identify and mark regions of | ||
| interest that may be suspicious for | ||
| lung nodules and masses on chest | ||
| radiographs. It identifies features | ||
| associated with pulmonary nodules | ||
| and masses from 6-60mm in size. | ||
| Detection of suspicious findings by | ||
| VisiRad XR is intended as an aid only | ||
| after the physician has performed | ||
| an initial interpretation; it is not | ||
| intended to replace the review by a | ||
| qualified radiologist and is not | ||
| intended to be used for triage or to | ||
| make or confirm a diagnosis. The | ||
| intended patient population for | ||
| VisiRad XR consists of patients >21 | ||
| years of age on whom chest | ||
| radiographs have been acquired in | ||
| an outpatient or emergency | ||
| department setting. | The Auto Lung Nodule Detection is | |
| computer-aided detection software to | ||
| identify and mark regions in relation to | ||
| suspected pulmonary nodules | ||
| from 10 to 30 mm in size. It is | ||
| designed to aid the physician to review | ||
| the PA chest radiographs of adults as a | ||
| second reader and be used as | ||
| part of S-Station, which is operation | ||
| software installed on Samsung Digital | ||
| X-ray Imaging systems. Auto Lung | ||
| Nodule Detection cannot be used on | ||
| the patients who have lung lesions | ||
| other than abnormal nodules. | ||
| Image Modality | X-ray | X-ray |
| Study Type | Chest | Chest |
| Clinical Finding | Lung lesion detection using marked | |
| regions of interest (ROIs) | Lung lesion detection using marked | |
| regions of interest (ROIs) | ||
| Intended Users | Physician | Physician |
| Intended User | ||
| Workflow | Device intended as a second-reader | |
| for physicians interpreting chest | ||
| radiographs | Device intended as a second-reader | |
| for physicians interpreting chest | ||
| radiographs | ||
| Patient Population | Adults with Chest Radiographs | Adults with Chest Radiographs |
| Technology | Machine learning | Machine learning |
| Input Type | Digital X-rays in DICOM format | Digital X-rays in DICOM format |
| Imaging protocols | Chest AP/PA | Chest PA |
| Output | ROI marked on duplicated input | |
| image | Information for ROI to be | |
| marked on the duplicated | ||
| input image | ||
| Platform | Secure cloud-based processing and | |
| delivery of outputs | Secure on-premise processing | |
| and delivery of outputs |
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Image /page/5/Picture/1 description: The image shows the word "IMIDEX" in blue font, with a stylized butterfly-like image to the left of the word. The butterfly image is made up of swirling lines in shades of red and orange. The letters of the word "IMIDEX" are in a simple, sans-serif font.
8.2 Comparison of Indications
- 8.2.1 VisiRad XR and Samsung ALND both analyze chest radiographs for the presence of lung nodules, return regions of interest (ROIs) on a secondary DICOM and act as a second-read for clinicians. VisiRad XR detects masses in addition to nodules (lesions are considered a "mass" if they are greater than 30mm in diameter, while a "nodule" is less than 30mm in diameter) and is a cloud-based software that operates on both AP and PA image views, as well as multiple chest radiograph hardware systems. Samsung ALND is limited to PA view images and its own S-Station hardware and software system. Both devices are only intended as an aid to the physician and not intended to replace the diagnosis by the physician. The differences in Indications for Use do not constitute a new intended use, as both devices are intended to assist physicians in identifying suspicious regions on chest radiographs and marking them with ROIs.
8.3 Comparison of technological characteristics
- 8.3.1 Performance and clinical testing were performed to support the safety and effectiveness of the technological differences between VisiRad XR and the predicate device. The results of these tests demonstrate that VisiRad XR has been designed and tested to conform to its intended use and comparably to the predicate device. Technological differences do not present any new safety or effectiveness concerns. As such, it can be considered substantially equivalent to the predicate devices.
9 Software Verification and Validation
- Non-clinical Performance Testing ਰੇ. I
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Image /page/6/Picture/0 description: The image shows the logo for IMIDEX. The logo consists of a complex, swirling design on the left, resembling a butterfly or a figure eight, with colors ranging from orange to red. To the right of the design is the word "IMIDEX" in large, blue, sans-serif font. The letters are spaced apart, giving the logo a clean and modern look.
- 9.1.1 Software verification and validation testing were conducted to provide evidence that VisiRad XR meets user needs and its intended use. Testing results demonstrate that the software specifications meet acceptance criteria and support claims of substantial equivalence. Documentation is provided as recommended by FDA's Guidance for Industry and FDA Staff, "Guidance for the Content of Premarket Submissions for Software Contained in Medical Devices."
- 9.1.2 A standalone performance test was executed on VisiRad XR to demonstrate generalizability and performance endpoints on a broad, representative dataset. The dataset consisted of data from three sources: National Lung Screening Trials (NLST) and two independent data sites. NLST is a high-quality, outpatient dataset that enrolled current or former heavy smokers. NLST consists of a set of patients that did not have lung cancer at study initiation, with geographic and demographic representation across the country. The two independent sites were a Level II trauma center at a rural group practice in Montana and a Level I trauma center in a metropolitan area of Colorado. Data was acquired from each site's emergency department between 2016 and 2021.
- 9.1.3 The primary endpoint for the standalone performance test was device sensitivity calculated at an image level. The study was executed at a fixed operating threshold. Study results demonstrated an overall sensitivity of 0.83 (95% Cl: 0.81-0.84) with average false positives per image of 1.5.
- 9.1.4 Device performance was stratified across multiple subgroups (age, gender, race, hardware used). Device performance remains consistent between gender, age groups and hardware type used.
- 9.1.5 Area Under the Curve (AUC) of the Receiver Operating Characteristic (ROC) curve was assessed as a secondary endpoint in the standalone performance test. Overall AUC, calculated non-parametrically, was 0.73 (95% Cl: 0.71-0.74).
- 9.1.6 The software level of concern for VisiRad XR is Moderate, since a malfunction of, or a latent design flaw in, the software device may lead to an erroneous diagnosis or a delay in delivery of appropriate medical care that would likely lead to Minor Injury.
9.2 Clinical Performance Testing
- 9.2.1 IMIDEX conducted a fully-crossed multiple reader, multiple case (MRMC) retrospective reader study at two sites to validate the impact of VisiRad XR on reader performance in detecting pulmonary nodules and masses on chest radiographs. The study consisted of 24 clinical readers (12 per site) and 600 total patient images (300 per site).
- 9.2.2 The study was performed on retrospective chest radiographs taken on patients in emergency department and outpatient settings. The subject population was composed of patients from across the United States (data collection sites included Colorado, Ohio, New Jersey, South Carolina, lowa and Wisconsin) who represent the range of age, racial and ethnic groups and geographic diversity that are representative of the intended use population. Women made up 56% of the study; of the population that disclosed racial data, 47% of the patient population identified as a racial group other than white or Caucasian.
- 9.2.3 The results of subgroup analyses showed that there were no clinically meaningful differences among the different demographic populations in study outcomes; reader performance improved across all evaluated demographic subgroups with the use of VisiRad XR.
- 9.2.4 The readers participating in the study were radiologists from multiple regions within the US with varied years of experience and specialties. They were de-identified for the purposes of the study.
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Image /page/7/Picture/0 description: The image shows the logo for IMIDEX. The logo consists of a complex, swirling, three-dimensional figure on the left, resembling a butterfly or a figure eight, rendered in shades of red and orange. To the right of the figure is the word "IMIDEX" in large, sans-serif, blue font. The letters are spaced apart, giving the logo a clean and modern appearance.
- 9.2.5 The study was conducted sequentially to simulate use of the product in clinical practice. Readers interpreted the same radiograph twice in a row, first unaided then aided by VisiRad XR. They were asked to interpret the radiographs as they would in standard clinical practice and note nodules or masses with a bounding box and associated level of confidence in their interpretation.
- 9.2.6 The study compared unaided and aided radiologist performance at detecting pulmonary nodules and masses as compared to the reference standard. The primary objective of the study was to determine whether the accuracy of readers aided by VisiRad XR was superior to the accuracy of readers unaided by VisiRad XR as determined by the image-level Area Under the Curve (AUC) of the Receiver Operating Characteristic (ROC) curve. For both sites, the use of VisiRad XR improved readers' AUC with statistical significance. Mean AUCs for the two conditions calculated across all readers were compared using a two-sided test at the alpha=0.05 level of significance with a p value