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Rapid LVO is a radiological computer aided triage and notification software indicated for use in the analysis of CTA head images. The device is intended to assist hospital networks and trained radiologists in workflow triage by flagging and communication of suspected positive ICA or MCA-M1 Large Vessel Occlusion (LVO) findings in head CTA images.

Rapid LVO uses a software algorithm to analyze images and highlight cases with suspected LVO on a server or standalone desktop application in parallel to the ongoing standard of care image interpretation. The user is presented with notifications for cases with suspected LVO findings. Notifications include compressed preview images. These are meant for informational purposes only and are not intended for diagnostic use beyond notification. The device does not alter the original medical image and is not intended to be used as a diagnostic device.

The results of Rapid LVO are intended to be used in conjunction with other patient information and based on professional judgment, to assist with triage /prioritization of medical images. Notified clinicians are responsible for viewing full images per the standard of care.

Rapid LVO is a radiological computer-assisted triage and notification software device. The Rapid LVO module is a contrast enhanced CTA module which operates within the integrated Rapid Platform to provide triage and notification of suspected ICA and MCA-M1 Large Vessel Occlusion (LVO) based on the following definitions:

ICA Occlusion: A high-grade stenosis or occlusion of the intracranial portion of the ICA.

MCA-M1 Occlusion: A high-grade stenosis or occlusion of the horizontal segment of the MCA-M1, defined as the segment which extends from the ICA terminus until the vessel has turned upward into the Sylvian fissure. This includes post-bifurcation M1 segments in some patients.

The LVO module uses traditional programming algorithms. The output of the module is a priority notification to clinicians indicating the suspicion of LVO based on positive findings. The Rapid LVO module uses the basic services supplied by the Rapid Platform including DICOM processing, job management, imaging module execution and imaging output including the notification and compressed image.

The Rapid LVO device, a radiological computer-aided triage and notification software for detecting Large Vessel Occlusions (LVO) in CTA head images, was evaluated against specific acceptance criteria.

1. Table of Acceptance Criteria and Reported Device Performance

Additionally, the following performance metrics were reported:

• Positive Predictive Value (PPV): 0.98
• Negative Predictive Value (NPV): 0.96
• Receiver Operating Characteristic (ROC) AUC: 0.99

2. Sample Size and Data Provenance for the Test Set

   • Sample Size: 217 scans (135 positive LVO cases, 82 negative LVO cases).
   • Data Provenance: The data was collected from 8 sites/studies, with locations in both the US and OUS (Outside the US). The document does not explicitly state if the data was retrospective or prospective, but clinical validation testing typically uses retrospective data for ground truth establishment.

3. Number of Experts and Qualifications for Ground Truth

   • Number of Experts: Three expert neuroradiologists.
   • Qualifications: They are described as "expert neuroradiologists." Specific years of experience are not provided.

4. Adjudication Method for the Test Set

   • The ground truth was established using a "2:3 concurrence" method. This implies that at least two out of the three expert neuroradiologists had to agree on the presence or absence of an LVO for a case to be assigned its ground truth label.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

   • No MRMC comparative effectiveness study was mentioned. The study focused on the standalone performance of the algorithm.

6. Standalone Performance Study

   • Yes, a standalone performance study was conducted. The reported sensitivity, specificity, PPV, NPV, and ROC AUC are all measures of the algorithm's performance without human-in-the-loop assistance.

7. Type of Ground Truth Used

   • The ground truth was established by "expert neuroradiologists" using a "2:3 concurrence" method. This indicates expert consensus was the basis for the ground truth.

8. Sample Size for the Training Set

   • The document does not explicitly state the sample size used for the training set. It only details the validation set used for performance testing.

9. How Ground Truth for the Training Set Was Established

   • The document does not provide details on how the ground truth for the training set was established. It only describes the ground truth establishment for the validation/test set.

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Rapid LVO is a radiological computer aided triage and notification software indicated for use in the analysis of CTA head images. The device is intended to assist hospital networks and trained radiologists in workflow triage by flagging and communication of suspected positive Large Vessel Occlusion (LVO) findings in head CTA images.

Rapid LVO uses a software algorithm to analyze images and highlight cases with suspected LVO on a server or standalone desktop application in parallel to the ongoing standard of care image interpretation. The user is presented with notifications for cases with suspected LVO findings. Notifications include compressed preview images, that are meant for informational purposes only and not intended for diagnostic use beyond notification. The device does not alter the original medical image and is not intended to be used as a diagnostic device.

The results of Rapid LVO are intended to be used in conjunction with other patient information and based on professional judgment, to assist with triage /prioritization of medical images. Notified clinicians are responsible for viewing full images per the standard of care.

Rapid LVO 1.0 is a clinical module which operates within the integrated Rapid Platform to provide triage and notification of suspected Large Vessel Occlusion (LVO). The Rapid LVO module consists of the core Rapid Platform software which provides the administration and services for the Rapid image processing modules; and the Rapid LVO module which functions as one of many image processing modules hosted by the platform.

Rapid LVO acquires (DICOM compliant) medical image data from CTA scanners through the Rapid Platform interface.

The Rapid platform is a software package that provides for the visualization and study of changes in tissue using digital images captured by diagnostic imaging systems including CT (Computed Tomography), CTA, XA and MRI (Magnetic Image Resonance), as an aid to physician diagnosis. Rapid can be installed on a customer's Server or it can be accessed online as virtual system. It provides viewing, quantification, analysis and reporting capabilities. The Rapid platform has multiple modules a clinician may elect to run and provide analysis for decision making. The basic architecture supports the general functionality to support the Rapid LVO imaging module such as DICOM interfaces, job management, data base functions and communications. The Rapid Platform and base functions are not under review for this submission.

The provided document (K200941) describes the 510(k) premarket notification for the iSchemaView Rapid LVO 1.0 device. Here's a breakdown of the acceptance criteria and the study proving the device meets them:

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria for standalone performance were specified as exceeding an 80% goal for both Sensitivity (Se) and Specificity (Sp) using the lower bound of the 95% Confidence Interval. Additionally, a time-to-notification goal of less than 3.5 minutes was established based on the predicate device.

As shown in the table, all reported performance metrics exceeded the specified acceptance criteria.

2. Sample Size Used for the Test Set and Data Provenance

The document mentions that iSchemaView performed "standalone performance in accordance with the 892.2080 special controls to show acceptance of the clinical performance of the Rapid LVO module." However, the exact sample size used for this test set is not explicitly stated in the provided text.

Regarding data provenance, the document does not specify the country of origin for the clinical data used in the performance validation. It only broadly states that the Rapid System performance "has been validated through the use of phantoms (Rapid core indications) and clinical data (Rapid LVO)." It is retrospective data, as it was used for validation after development, rather than prospectively collected for the clinical trial.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts

The document does not explicitly state the number of experts used to establish the ground truth for the test set or their specific qualifications (e.g., "radiologist with 10 years of experience").

4. Adjudication Method for the Test Set

The document does not describe any specific adjudication method (e.g., 2+1, 3+1, none) used for establishing the ground truth of the test set. It implies that the "clinical data" was used for validation, but the process of expert consensus or adjudication is not detailed.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and Effect Size

A Multi-Reader Multi-Case (MRMC) comparative effectiveness study was NOT done according to the provided text. The study described is a "standalone performance" evaluation, meaning it assesses the algorithm's performance independent of human readers. Therefore, there is no information about how human readers improve with or without AI assistance in this document.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done

Yes, a standalone performance study was done. The document explicitly states: "iSchemaView performed standalone performance in accordance with the 892.2080 special controls to show acceptance of the clinical performance of the Rapid LVO module." The reported Sensitivity, Specificity, and ROC AUC are metrics of this standalone performance.

7. The Type of Ground Truth Used

The document refers to "clinical data" as the basis for the Rapid LVO performance validation. While it doesn't explicitly state "expert consensus" or "pathology" as the ground truth method, for radiological computer-aided triage software, the ground truth is typically established by expert consensus (e.g., multiple expert radiologists reviewing cases and reaching a consensus on the presence or absence of LVO) or by clinical outcomes data (e.g., confirmation of LVO through other gold standard diagnostics or surgical findings). Given the nature of the device for triage and notification, it is highly likely that the ground truth was established by expert consensus of radiologists or neurologists, possibly combined with clinical follow-up data to confirm true LVO. However, the document does not definitively specify which.

8. The Sample Size for the Training Set

The document does not specify the sample size for the training set. It only mentions that the device uses "a software algorithm to analyze images."

9. How the Ground Truth for the Training Set Was Established

The document does not describe how the ground truth for the training set was established. It briefly mentions that the predicate device (Rapid ICH) uses "machine learning software implementations," while Rapid LVO uses "traditional algorithms," but it does not detail the training data or its annotation process for either.

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