(283 days)
The Konica Minolta Xpress Digital Mammography System is a software device that is used in conjunction with a specified Konica computed radiography system, REGIUS Model 190 or REGIUS Model 210 with REGIUS Cassette Plate CP1M200 and the REGIUS Console CS-3000, and a mammography x-ray unit, to produce full field digital mammography images. The Xpress Digital Mammography software with a specified Konica Minolta computed radiography system is designed to replace screen-film based systems for the production of mammographic images. The device is intended to be used for screening and diagnosis of breast cancer. The mammographic images can be interpreted by a qualified physician using either hard copy film or soft copy display at a workstation.
Konica Minolta's Xpress Digital Mammography is a software device that is used in conjunction with currently marketed Konica computed radiography systems to acquire Full Field Digital Mammography Images. Digital mammography can be performed with the specified Konica Minolta computed radiography systems including the activated Xpress Digital Mammography software using any mammography x-ray unit legally marketed in the U.S .. Konica Minolta does not specify a mammography x-ray unit for use with the specified Konica Minolta computed radiography system with the activated Xpress Digital Mammography software.
The components of the specified Konica Minolta computed radiography systems for digital mammography include either REGIUS Models 190 (K052095) or 210 (K092717) Direct Digitizers and the REGIUS Console CS-3000 medical image processing workstation (K051523) with optional bar code reader accessories.
The x-ray images produced by the legally marketed x=ray unit:are captured on a REGIUS image plate and digitized using either REGIUS Model 190 or 210 Direct. Digitized images are imported into the REGIUS Console CS-3000 workstation. The REGIUS Console CS-3000 is identical to the REGIUS Console CS-3000 described in K051523, with the Xpress Digital Manimography software activated. The Xpress Digital Mammography software prov a high resolution reading capability and display options specific to the review of mammographic image.
Soft. copy images can be transferred to any legally marketed diagnostic viewing station that accepts DICOM 3 input. Hard copy images can be generated using any printer legally marketed for use in digital mammography that supports DICOM basic grayscale print management service with a maximum 50 micrometer pixel pitch and film minimum optical density of at least 3.6.
Here's a breakdown of the acceptance criteria and study information for the Konica Minolta Xpress Digital Mammography System, based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
The document primarily focuses on demonstrating non-inferiority to predicate devices (Fuji Computed Radiography Mammography Suite - FCRMS) and traditional screen-film mammography, rather than specific numerical acceptance thresholds. Therefore, the "acceptance criteria" are implied by the non-inferiority claims, and the "reported device performance" reflects how the device compared to the predicate/screen-film.
| Acceptance Criteria (Implied by Non-Inferiority) | Reported Device Performance |
|---|---|
| Non-Clinical / Physical Performance: | |
| Sensitometric Response: Linear relationship between pixel value and radiation exposure maintained. | Linear relationship between pixel value and exposure maintained for all exposure conditions (R-squared = 1.00). |
| Spatial Resolution (Presampling MTF): Equivalent or better than FCRMS. | Presampling MTF of Xpress Digital Mammography is equivalent or better than FCRMS. |
| Dynamic Range (Average DQE): Equivalent or better than FCRMS. | Average DQE of Xpress Digital Mammography is equivalent or better than FCRMS. |
| Image Erasure: No residual signals after erasure. | No residual signals observed after erasure. |
| Image Fading: Initial decline in luminescence intensity during 2 hours following exposure acceptable. | Initial decline in luminescence intensity during 2 hours following the exposure was 20% at 30 degrees Celsius. (No explicit acceptance range given, but presented as acceptable.) |
| Image Retention: No signal observed after repeated exposures and erasures. | No signal observed after 100 cycles of exposures and erasures. |
| Fogging after Exposure to Room Light: No signal fogging or depletion. | No signal fogging or depletion observed after 5 minutes exposure to light of 7000 Ix luminance (more than ten times ordinary room condition). |
| Repeated Exposure Test (Lag value): Acceptable lag value. | Resultant lag value was 0.0047. (No explicit acceptance range given, but presented as acceptable.) |
| Phantom Testing (CDMAM IQF): Comparable to FCRMS. | IQF results generally comparable across soft-copy, hard-copy, and FCRMS, with hard-copy 1.47mGy showing the highest IQF. Implicitly met, as no inferiority claims were made. |
| Phantom Testing (ACR Phantom Scores): Equivalent or better than FCRMS and film-screen systems. | ACR phantom scores for fibers, specks, and masses were equivalent or better than FCRMS and a film-screen system (Min-R EV/Min-R EV150) for both hard-copy and soft-copy display. |
| Clinical Performance: | |
| ROC Curves (AUC): Non-inferior to Screen-Film Mammography. | Observed difference in AUC about 1%, with upper one-sided 95% confidence limits less than 5%, indicating non-inferiority to Screen-Film Mammography. |
| Specificity: Non-inferior to Screen-Film Mammography. | Difference in specificities about 2% favoring Xpress system, with upper one-sided confidence limit (GEE analysis) less than 0.05. Supportive ROC curve analysis also demonstrated non-inferiority. |
| Sensitivity: Non-inferior to Screen-Film Mammography. | Not non-inferior by GEE analysis. However, ROC curve analysis indicated that at a specificity of 90%, the upper one-sided confidence limit on the sensitivity of Screen-Film minus the Xpress system was less than 0.10. (Acknowledged bias due to recruitment of suspicious Screen-Film cases). |
| Features Analysis: No loss of detail compared to Screen-Film. | Xpress system favored for visualization of the skin line; little evidence of a difference for other features. Indicates no loss of detail. No trend favoring hard image to soft image for Xpress system. |
| Overall Safety and Effectiveness: Safe and effective for screening and diagnosis of breast cancer. | Demonstrated safe and effective for screening and diagnosis of breast cancer based on ROC analyses, sensitivity, specificity, recall rates, and features analyses, with images not inferior to conventional Screen-Film images. |
2. Sample Size Used for the Test Set and Data Provenance
- Test Set Sample Size (Clinical Study): 210 subjects
- 60 pathology-proven cancers
- 130 benign abnormal subjects (benign biopsy findings)
- 20 negative subjects (confirmed by negative one-year follow-up mammography)
- Data Provenance: Prospective, non-randomized, non-blinded clinical trial conducted at 11 clinical investigational centers. The country of origin is not explicitly stated but implies the US given the FDA submission. Both standard screen-film mammograms and Xpress Digital mammograms were acquired.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
- Ground Truth for Clinical Study:
- Pathology: For the 60 cancer cases and 130 benign abnormal cases, ground truth was established by pathology reports.
- Follow-up Mammography: For the 20 negative cases, ground truth was established by negative one-year follow-up mammography.
- Experts for Phantom Testing: 3 observers participated in rating both the CDMAM and ACR phantoms.
- Observer A: Seven years' experience of phantom scoring.
- Observer B: Five years' experience of phantom scoring.
- Observer C: Five years' experience of phantom scoring.
4. Adjudication Method for the Test Set
- Clinical Study: Not explicitly described as an adjudication method for ground truth. However, 11 radiologists interpreted the 210 cases, scoring each with a BIRADS score and probability of malignancy. The text states, "The final study cohort consisted of 210 subjects: 60 pathology proven cancers, 130 benign abnomal subjects (benign biopsy findings), and 20 negative subjects (confirmed by negative one year follow-up mammography)." This implies that the ground truth for individual cases (cancer/benign/negative) was established independently (pathology/follow-up) rather than through radiologist consensus on the test images themselves. The radiologists' interpretations were then compared against this established ground truth.
- Phantom Testing: The average scores of all three observers were calculated for the CDMAM phantom (contrast-detail diagrams and IQF results) and the ACR phantom (fibers, specks, masses scores). This is a form of consensus/averaging rather than adjudication for differing interpretations.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
Yes, a multi-reader, multi-case study was performed as part of the clinical trial.
- Human Readers: 11 radiologists interpreted the 210 screen-film and Xpress Digital images. They were blinded to patient histories, mammography films, and results.
- AI (Device) vs. Human Readers: This study compared the device (Xpress Digital) to traditional screen-film mammography, both interpreted by human readers. It did not directly measure the effect size of how much human readers improve with AI vs. without AI assistance (i.e., AI-assisted reading vs. unassisted reading). Instead, it compared two different imaging modalities (digital vs. film), both interpreted by humans. The device itself is the imaging system, not an AI interpretation aid.
6. Standalone (Algorithm Only Without Human-in-the-Loop Performance) Study
No. The clinical study involved human radiologists interpreting both the Xpress Digital mammograms and the screen-film mammograms. The device itself is an imaging system, not an AI algorithm for automated interpretation.
7. Type of Ground Truth Used
- Clinical Study:
- Pathology: For cancer cases and benign abnormal subjects (biopsy findings).
- Outcomes Data (Follow-up Mammography): For negative subjects (negative one-year follow-up mammography).
8. Sample Size for the Training Set
The document does not mention a training set or any machine learning components that would require one. The Xpress Digital Mammography System is described as a "software device" for image acquisition and display, and the studies performed relate to its physical and clinical performance as an imaging system, not an AI diagnostic algorithm.
9. How the Ground Truth for the Training Set Was Established
Not applicable, as no training set or machine learning components are described or implied.
§ 892.1715 Full-field digital mammography system.
(a)
Identification. A full-field digital mammography system is a device intended to produce planar digital x-ray images of the entire breast. This generic type of device may include digital mammography acquisition software, full-field digital image receptor, acquisition workstation, automatic exposure control, image processing and reconstruction programs, patient and equipment supports, component parts, and accessories.(b)
Classification. Class II (special controls). The special control for the device is FDA's guidance document entitled “Class II Special Controls Guidance Document: Full-Field Digital Mammography System.”See § 892.1(e) for the availability of this guidance document.