(200 days)
The Digi-One System is indicated for non-invasive evaluation of intracranial and extracranial vascular flow velocity irregularities in adults and in children. It is not intended for fetal use. It is not intended for neonatal use.
The Digi-One System is a small, lightweight, portable digital Transcranial Doppler (TCD) system with an advanced M-mode display which can be connected to any external Windows based PC. It measures the blood flow velocity in the main cerebral arteries non-invasively for circulation diagnosis and HITS (High Intensity Transient Signals) detection using the same Rimed TCD software application as the predicate device. The Digi-One System is a modification of the Digi-Lite System. The hardware was modified using current electronic components, and the software was modified to allow installation on a dedicated PC (such as a laptop device). Otherwise, the functionality of the system remains identical to that of the Digi-Lite system in all aspects, including acoustic power outputs, clinical parameter measurement accuracy, examination modes, available transducers, software menus and commands (with some minor user interface modifications).
The description of the acceptance criteria and study proving the device meets said criteria is derived from the provided text.
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria for the Digi-One System were based on its substantial equivalence to the predicate device, the Digi-Lite System (K062578). This meant demonstrating that key characteristics and performance metrics were identical or acceptably similar.
| Acceptance Criteria Category | Specific Criteria | Reported Device Performance (Digi-One System) |
|---|---|---|
| Technological Equivalence | - Product Code, Class identical to predicate | - IYN, ITX; Class II (Identical to predicate) |
| - Indications for Use identical to predicate | - "The Digi-One System is indicated for non-invasive evaluation of intracranial and extracranial vascular flow velocity irregularities in adults and in children. It is not intended for fetal use. It is not intended for neonatal use." (Identical to predicate) | |
| - Energy Used / Delivered identical to predicate | - Ultrasound energy (Identical to predicate) | |
| - Mechanism of Action identical to predicate | - Doppler Ultrasound, with modes: Unilateral, Bilateral, Multichannel, Monitoring, Multidepth (up to 8 spectrums at various depths), M-Mode (64 gates). (Identical to predicate, except "Multifrequency" not listed for Digi-One, but "functionality... remains identical to that of the Digi-Lite system in all aspects"). | |
| - Accessories identical or within acceptable limits | - Probe types: 1MHz PW, 2MHz PW, 4MHz PW/CW, 8MHz PW/CW. Remote control, Monitoring probe holder, Color printer, Footswitch. (Identical to predicate, though predicate also lists "CD ROM backup" and "DAT Tape" which are not mentioned for Digi-One, implying these are considered minor or external). | |
| Performance Equivalence | - Sample volume identical to predicate | - (for 1 MHz) 15-92 mm, (for 2 MHz) 15-146 mm (Identical to predicate) |
| - Power (%) identical to predicate | - 0-100% at 7% steps (Identical to predicate) | |
| - Acoustic output (Ispta) identical to predicate | - 1MHz PW Ispta=34.15mW/cm2; 2MHz PW Ispta=181.3mW/cm2; 4MHz PW Ispta=232.2mW/cm2; 4MHz CW Ispta=183mW/cm2; 8MHz PW Ispta=149.8mW/cm2; 8MHz CW Ispta=414mW/cm2. (Identical to predicate) | |
| Software Functionality | - Software functions and testing modes did not change from predicate (excluding minor UI improvements) | - "The software functions and testing modes did not change, except for some User Interface improvements" (Confirmed) |
| Safety & Effectiveness | - Maintain safety and efficacy with modified hardware/software | - "As the specifications remain identical, the safety and efficacy of the device are not affected when used as labeled." and "Performance testing of the modified device included measurements of output power and measurement accuracy. The testing results demonstrated that the modified device is substantially equivalent to the predicate, unmodified device." |
| Low-Power Modes | - System defaults for low-power modes equivalent to predicate | - "the system defaults for low-power modes were reviewed for equivalence to the predicate device, and were demonstrated to remain identical." (Confirmed) |
| Regulatory Compliance | - Compliance with relevant safety and EMC standards | - Electrical and Mechanical Safety Standard (IEC 60601-1) met; Electromagnetic Compatibility Standard (IEC60601-1-2) met. |
| - Software Validation according to FDA Guidelines | - Software Validation according to FDA Guidelines (tested modified software) (Confirmed) |
2. Sample Size Used for the Test Set and Data Provenance
The document does not explicitly state a specific "test set" sample size in terms of patient data or clinical cases for the performance evaluation. The testing primarily focused on bench testing and software validation to demonstrate equivalence to the predicate device, rather than a new clinical trial with a defined patient cohort.
- Data Provenance: The study described is primarily a bench-testing and software validation study focused on the technical performance of the device and its equivalence to a predicate. It is not described as using retrospective or prospective clinical data from specific countries of origin for a test set.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
Given that the performance testing described is primarily bench testing to validate output energies and parameter calculation accuracies, along with software validation, there is no mention of "experts" being used to establish a clinical ground truth for a test set in the traditional sense of medical image interpretation or diagnosis. The ground truth for these technical tests would be established through calibrated measurement equipment and engineering standards.
4. Adjudication Method for the Test Set
As there is no described clinical "test set" involving human interpretation or diagnosis from the provided text, there is no mention of an adjudication method (e.g., 2+1, 3+1, none).
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
No, an MRMC comparative effectiveness study is not mentioned in the provided document. The study described is focused on demonstrating substantial equivalence to a predicate device through technical and software validation, not on comparing the effectiveness of human readers with vs. without AI assistance. The Digi-One System is a Transcranial Doppler (TCD) device for measuring blood flow velocity, not an AI-assisted diagnostic tool in the typical sense that would necessitate an MRMC study for improved human reader performance.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
The document describes the "Digi-One System" as a standalone device (a "small, lightweight, portable digital Transcranial Doppler (TCD) system"). Its performance evaluation involves "Bench testing to validate output energies and parameter calculation accuracies" and "Software Validation." These tests assess the device's intrinsic technical performance. So, yes, a standalone performance evaluation of the device's technical specifications was performed. This is implied by the testing that focused on its output parameters and accuracy without reference to human interpretation.
7. The Type of Ground Truth Used
The ground truth used for the performance testing consists of:
- Engineering Standards and Calibrated Measurements: For acoustic output, power, sample volume, and other physical parameters. Bench testing validates these against their expected values or those of the predicate.
- Software Validation Principles: For the software, adherence to FDA guidelines and verification that modified software maintains the functionality and accuracy of the predicate's software.
8. The Sample Size for the Training Set
The document does not describe a "training set" in the context of machine learning or AI algorithm development. The Digi-One System is a hardware and software modification of an existing TCD device. Its functionality relies on established Doppler ultrasound principles, not on a machine learning model that would require a training set.
9. How the Ground Truth for the Training Set Was Established
Since no training set for a machine learning algorithm is described, there is no information on how its ground truth would have been established.
§ 892.1550 Ultrasonic pulsed doppler imaging system.
(a)
Identification. An ultrasonic pulsed doppler imaging system is a device that combines the features of continuous wave doppler-effect technology with pulsed-echo effect technology and is intended to determine stationary body tissue characteristics, such as depth or location of tissue interfaces or dynamic tissue characteristics such as velocity of blood or tissue motion. This generic type of device may include signal analysis and display equipment, patient and equipment supports, component parts, and accessories.(b)
Classification. Class II.