(23 days)
The Presto 1000 transcranial Doppler ultrasound system is intended for use in the ICU and surgical suite as an ultrasound fluid flow analysis system for the monitoring of middle cerebral artery blood velocities. Vessels intended for monitoring are solely the M1 segments of the middle cerebral arteries via the temporal windows on the left and right sides of the head.
The Presto 1000 calculates cerebrovascular flow index values to identify the presence of hemodynamically significant deviations from normal values. It records changes in these indices over time for later review, displays trends in user selected flow indices, and generates alerts when user selected indices exceed user defined levels, based on physician requirements and patient needs.
The device is not intended to replace other means of evaluating vital patient physiological processes, such as pulse oximetry, electroencephalography or electrocardiography, is not intended to be used in fetal applications, and is not intended to be used in the sterile field.
The Presto 1000 is a color/PW transcranial Doppler (TCD) ultrasound monitor incorporating two permanently connected two-dimensional phased array transducers, to be used in a headset, for long term bilateral monitoring of blood flow in the M1 segment of the middle cerebral artery (MCA), through the temporal windows. Transducers are intended to be used with single use acoustic couples couplers, which increase patient comfort and improve mechanical compliance to maintain acoustic coupling during long term monitoring. Transducers may only be mounted to the headset when fitted with this acoustic coupler.
The provided text describes the PhysioSonics, Inc. Presto 1000 System, a Transcranial Doppler (TCD) Ultrasound System. The document is a 510(k) summary, which focuses on demonstrating substantial equivalence to a predicate device rather than conducting extensive de novo clinical studies with specific acceptance criteria related to a new AI algorithm's performance.
Based on the provided text, the Presto 1000 System is a diagnostic ultrasound device, not an AI-powered one. Therefore, the questions related to AI-specific acceptance criteria, test sets, expert ground truth, adjudication methods, MRMC studies, standalone performance, training sets, and ground truth establishment for training sets are not applicable to the information presented in this 510(k) summary.
The manufacturer did not perform clinical testing to show substantial equivalence for safety and effectiveness (Page 4, "4) Clinical Testing"). Instead, they relied on non-clinical performance testing and comparison to a predicate device.
Here's an analysis of the "acceptance criteria" and "study" as implied by the document for a non-AI medical device:
1. Table of "Acceptance Criteria" and Reported Device Performance (as implied for a non-AI device through substantial equivalence):
For a device seeking 510(k) clearance based on substantial equivalence, the "acceptance criteria" are implicitly met by demonstrating that the device is "at least as safe and effective" as a legally marketed predicate device. This is primarily done through technological comparison, non-clinical performance testing (e.g., acoustic output, accuracy using phantoms), and demonstrating compliance with relevant standards.
| Acceptance Criteria (Implied for Substantial Equivalence) | Reported Device Performance and Evidence Provided |
|---|---|
| Safety: | |
| - Biocompatibility: Materials in contact with patients are safe. | - "Patient contact materials have been shown to be biocompatible." (Page 3) |
- Complies with ISO 10993-5 (In Vitro cytotoxicity) and ISO 10993-10 (Irritation and skin sensitization). (Page 3) |
| - Electrical Safety: Meets relevant electrical safety standards. | - Complies with IEC 60601-1 (General Requirements for Safety), IEC 60601-1-2 (Electromagnetic compatibility), and IEC 60601-2-37 (Ultrasonic medical diagnostic and monitoring equipment). (Page 3) |
| - Acoustic Output Safety (ALARA principle): Acoustic output is within safe limits for transcranial use. | - "Global Maximum Cranial Thermal Index (TIC) of 2.6 in Locating mode / 2.3 in Monitoring mode, and Mechanical Index (MI) of 1.0 are consistent with the monitoring function of the predicate device." (Page 4) - Maximum Monitoring intensity of 420 mW/cm² (exceeds pre-amendment cephalic limit of 94 mW/cm², consistent with predicate and other modern TCD systems). (Page 4)
- Time-average acoustic exposure reduced by factors of two or four with bilateral monitoring or 50% duty cycle operation. (Page 4)
- Complies with NEMA UD2-2004 (Acoustic Output Measurement Standard) and NEMA UD3-2004 (Real Time Display of Thermal and Mechanical Acoustic Output Indices). (Page 3, 4) |
| - Mechanical/Thermal Safety: Device operates safely without overheating or mechanical failure. | - Non-clinical testing conducted to support thermal, mechanical, electromagnetic, and mechanical safety per FDA Guidance and applicable sections of standards like IEC 60601-1. (Page 3) |
| Effectiveness/Performance: | |
| - Accuracy of Flow Velocity Measurement: Measures blood flow velocity accurately. | - "Evaluated the fundamental accuracy of measured flow velocity using calibrated string phantoms and calibrated volume flow phantoms with a blood mimicking fluid." (Page 3) - "Results were compared with similar measurements performed with the Spencer TCD 100M predicate system, and found to be identical within experimental uncertainties." (Page 4) |
| - Performance of Secondary Flow Indices: Calculations for derived indices are verified. | - "Calculations used to derive secondary flow indices are additionally verified with simulated and electronic data, which allows evaluation to higher accuracy than the reported numbers determined from acoustic measurements." (Page 3) |
| - Doppler Sensitivity and Phased Array Functionality: Ability to locate and track peak flow. | - "Additional testing verified the Presto 1000's use of phased array technology to locate the peak Doppler signal in the region of interest, and evaluated Doppler sensitivity; both were found appropriate to the intended use." (Page 4) |
| - Substantially Equivalent to Predicate Device: Intended use, modes, clinical measurements, acoustical power output, head fixation devices, safety, and effectiveness are comparable. | - Detailed comparison table and narrative stating substantial equivalence in all these aspects to the Spencer TCD 100M (K002533). (Page 2-3) "The Presto 1000 and its transducers are substantially equivalent to its currently marketed predicate device... with regard to intended use, modes, clinical measurements, acoustical power output, head fixation devices, safety and effectiveness." (Page 2) |
2. Sample Size Used for the Test Set and Data Provenance:
- Test Set: For the performance tests (acoustic output, accuracy of flow velocity, etc.), the samples were physical phantoms (calibrated string phantoms, calibrated volume flow phantoms with blood mimicking fluid) and simulated/electronic data. The exact "sample size" in terms of number of phantom runs or data points is not specified, but the testing was conducted in a non-clinical laboratory setting.
- Data Provenance: Not applicable as it wasn't a clinical study with patient data. The non-clinical testing was performed by PhysioSonics, Inc.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications:
- Not applicable as the "ground truth" for non-clinical performance testing was established by the physical properties of the phantoms, reference measurements, and validated internal calculations. There were no human experts adjudicating diagnostic accuracy from images in this context.
4. Adjudication Method for the Test Set:
- Not applicable. The non-clinical testing involved direct measurement against standards and comparison to a predicate device's measured performance on phantoms.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done, and its effect size:
- No MRMC comparative effectiveness study was done. The document explicitly states: "The Presto 1000 did not require clinical testing to show substantial equivalence to its predicate device in safety and effectiveness." (Page 4)
6. If a Standalone (i.e. algorithm only without human-in-the loop performance) was done:
- This question is tailored for AI devices. For this traditional diagnostic ultrasound device, "standalone performance" refers to the device's ability to accurately measure physical parameters (like flow velocity) on test phantoms, which was indeed done. The device's "algorithm" (signal processing for Doppler shifts, flow indices) was tested for its calculation accuracy using simulated and electronic data.
7. The Type of Ground Truth Used:
- For non-clinical performance testing, the ground truth was physical measurements from calibrated phantoms and verified mathematical calculations against simulated and electronic data.
8. The Sample Size for the Training Set:
- Not applicable. This is a traditional medical device, not an AI/Machine Learning model that requires a "training set" in the conventional sense. The device's underlying signal processing is based on established physics principles of Doppler ultrasound.
9. How the Ground Truth for the Training Set Was Established:
- Not applicable, as there was no AI/ML "training set." The device's functionality is based on established engineering and physics principles.
§ 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.