AWS Architecture Blog
Using AppStream 2.0 to Deliver PACS and Image Analysis in Clinical Trials
Hospitals and clinical trial sites manage sensitive patient data. They are often required to grant remote access to custom Windows-based applications for patient record review and medical image analysis. This typically requires providing physicians and staff with remote access to on-premises workstations over VPN, with some flavor of remote desktop software. This can be both costly and inefficient, since it requires licensing custom 3rd party remote access tools, configuring network access for each researcher, and training individuals at each site for every trial. In combination with other AWS services, Amazon AppStream 2.0 can be used to build better workflows. Applications delivered via AppStream 2.0 can be used to review patient data, such as medical images, videos, and patient records. At the same time, this approach offers greater protection of patient data, without the cost and complexity of a remote desktop solution. In this blog, we will present a high-level architecture and several example use cases for leveraging AppStream 2.0 for medical image analysis.
Background – managing patient data security
Picture archiving and communications systems (PACS) and vendor neutral archives (VNAs) are used extensively for storing and managing medical images and related metadata. These systems are critical for sharing images among modern medical teams collaborating on patient care. Furthermore, researchers and clinicians can access images from PACS and view them at a workstation in an office or clinic setting.
While data sharing is critical for healthcare and research workflows, HIPAA-covered entities are responsible for protecting patient’s personally identifiable information (PII) as protected health information (PHI). As such, HIPAA-covered entities are bound to protect any information about a patient’s healthcare, health status, and payment history for services.
Data sovereignty leads to further complications. Clinical trials play an essential role in vouching for the safety and efficacy of medical products and innovations. The increasing transparency in clinical trial data makes sharing this information among researchers, clinicians, patients, and trial subjects possible. However, this also makes it a challenge to maintain stakeholder’s control over their data. With laws like General Data Protection Regulation (GDPR) and the emphasis on data localization, data sovereignty is interpreted based on the location of the data. Further, regulations like 21 CFR Part 11 impose strict guidelines on data protection, authentication, and validation for any FDA-regulated entity or use case.
If you are a healthcare organization or software provider, you understand the struggle to innovate and drive change, while maintaining your security and compliance posture for your applications. Your end users (physicians, radiologists, researchers, and remote operators) require IT environments that are easily accessible and can automatically scale globally on demand.
The network of professionals involved in image management and review is widely distributed, yet applications for review and analysis are still largely desktop-based. This means that a common use case for the healthcare industry is to use desktop applications from anywhere. Let’s use the following example to look more closely into a use case where AppStream 2.0 is helpful.
Data flow through the image management architecture
In this use case, the hospital’s on-premises systems are connected to the AWS Cloud using a private network connection, such as AWS Direct Connect, or an AWS Site-to-Site VPN. The images and files generated from the PACS server and the Electronic Medical Record (EMR) server are placed on an Amazon Simple Storage Service (Amazon S3). Amazon S3 is an object storage service that offers scalability, availability, security, and performance. All of the images and files are read from a secure S3 bucket, accessible only by the PACS. They are then de-identified and written back to a separate bucket accessible by other systems for review.
In our workflow, text-based PII is extracted from the images using Amazon Comprehend Medical. Amazon Rekognition helps to identify and detect “burned-in” PHI data (text that is actually part of the image). In addition, Amazon Rekognition can assist with entity identification within images. For example, in a batch of thousands of shoulder MRIs, Amazon Rekognition can identify a knee. Amazon SageMaker is an end-to-end machine learning platform that enables trial administrators and data management teams to prepare training data. It can also be used to build machine learning models quickly with pre-built algorithms. With Amazon SageMaker notebooks, the resulting de-identified image and text are written to the S3 bucket, and can then be used by the desktop applications.
AppStream 2.0 is a fully managed application streaming service that provides users with instant access to desktop applications from anywhere, regardless of what device is being used for access. An AppStream 2.0 image builder is used to install, add, and test your applications, and then create a software image or package. The software image contains applications that you can stream to your users. Default Windows and application settings allow your users to get started with their applications quickly. A fleet consists of fleet instances (also known as streaming instances) that run the software image that you specify. A stack consists of an associated fleet, user access policies, and storage configurations. A streaming instance (also known as a fleet instance) is an Amazon EC2 instance that is made available to a single user for application streaming.
Secure user interactions for image analysis and review
We’ve covered secure storage and anonymization of the image data that’s managed by the PACS, with images residing in Amazon S3. The next challenge is to provide secure, role-based access to those images for review by physicians, radiologists, or researchers. However, many of the applications used for image review and annotation are proprietary desktop applications that only run on specific operating systems. Traditionally, reviewers access these applications via remote desktop sessions to an on-premises workstation. This creates cost, management, network security, and data privacy concerns for the application hosts. Using Amazon AppStream 2.0, we can provide secure access to these proprietary applications in the cloud.
Authentication and access to the applications is as follows:
- When end users sign in with the provided AppStream 2.0 URL, they are authenticated against Active Directory.
- After the users are authenticated, the browser receives a Security Assertion Markup Language (SAML) assertion as an authentication response from Amazon Cognito, which controls access to AWS resources.
- The response is then posted by the browser to the AWS sign-in SAML endpoint. Temporary security credentials are issued after the assertion and the embedded attributes are validated.
- The temporary credentials are then used to create the sign-in URL.
- The user is redirected to the AppStream 2.0 streaming session and is granted access permissions based on the role assigned to them. After this, they can log into the AppStream 2.0 instance and access their applications.
The application configurations are stored as persistent data using Amazon FSx, which can provide every user a unique storage drive within AppStream 2.0 streaming sessions. A user will have permissions to access only their directory. The drive is automatically mounted at the start of a streaming session. Files added or updated to the drive are automatically persisted between streaming sessions.
Figure 1. Architecture for managing, anonymizing, and analyzing medical image data
Conclusion
In our high-level use case, we reviewed how a combination of AWS services can be used to increase efficiency and reduce cost. While managing and reviewing patient data using custom applications such as PACS or image viewers, AWS services also provide an improved end user experience. This architecture provides a scalable, reliable, and secure foundation to develop your solution, leveraging the image analysis applications you already use. Your applications are available through a standard web browser, and you can manage users, access, and data with existing Active Directory group memberships and credentials.
AppStream 2.0 manages the AWS resources required to host and run your applications, scales automatically, and provides access to users on demand. AWS services can be managed using configuration as code best practices through AWS CloudFormation. CloudFormation lets you define text-based templates used to spin up cloud architectures. In a more complex setup, AWS Glue, Amazon CloudWatch, and AWS CloudTrail configured with a centralized logging account can be added to achieve 21 CFR Part 11 and GxP compliance.
For additional information, check out the following resources or contact your AWS account manager.