MRIdb is an interesting new application for storing and managing images, from Imperial College London. Building upon the stalwart dcm4chee image store, it combines the functionality of a PACS with study-level management and access control, administered through a web interface. Also bundled is the PostgreSQL database for storing images and open source applications for viewing and converting images. MRIdb itself is the Java-based management application, and is the primary means of interaction with the system. Through this interface you log in (authentication with LDAP is supported), view or download images, and manage related images by grouping them into projects.
One unique aspect of this project is its optional deployment as a preconfigured virtual machine. This is a single downloaded file which is run within the VirtualBox application, a free application from Oracle that runs on any platform.
The virtual machine contains an entire CentOS Linux operating system, and all the MRIdb components, all configured and already running. Once started, the virtual machine (which in this case has the IP address 10.0.1.7) is accessible in a number of ways.
Firstly, the MRIdb application is accessed by browser through the default HTTP port of the VM. Here’s where you can create projects and associate them with individual scans, a convenient means of managing large numbers of studies, and a useful research-oriented feature not provided by traditional clinical PACS systems.
Features found in most PACS clients, such as search by various fields, are also available. Image viewing is provided in two ways, by launching an instance of the ImageJ viewer, or through the in-browser Weasis viewer.
Then, to communicate with MRIdb using DICOM standard protocols, the dcm4chee instance provides full PACS functionality. This is accessed using standard DICOM tools, such as a network-capable image viewer, another PACS, or any DICOM-compliant tools. For security, the default dcm4chee instance requires that remote AE titles be configured in order to send or receive studies. The server uses the standard port 11112 and AE Title ‘DCM4CHEE’, as shown in this example of sending an image to the store:
$ dcmsnd -L DCM4CHE DCM4CHEE@10.0.1.7:11112 IM-0001-0100.dcm
Alternatively, the dcm4chee instance has its own web interface, running on its standard port of 8080. Through this you can search the PACS directly, and configure your remote AE entities. It’s a pretty dense interface, but this is a commercial grade application.
Finally, you can SSH into the virtual machine itself. Always a kick to find another machine running within your computer. Log in to it, and you have a full Linux environment to explore the MRIdb components, which start running when the VM is initialized.
In this test, the virtual machine launched quickly and with no intervention required, consuming less than 1 GB of memory including the VirtualBox overhead. Routine tasks can be accomplished through the MRIdb browser interface, though steps specific to dcm4chee require a visit to its separate interface. Deploying from source code was less successful: as is common with complex Linux installations, there are many platform-dependent details that can trip up the installation and configuration scripts. Perhaps due to the deviation from CentOS as the test platform (Debian and Open SUSE were available), the packages did not install automatically. This is par for the course with complex multi-package installations and most people familiar enough with Linux to attempt the source-based path would be able to resolve the incompatibilities. The final stumbles were encountered when launching the in-browser viewers, and were caused not by the application, but by the delightful Java version/security/update maze we all love to navigate.
MRIdb is built on a good number of solid free and open-source projects. The imaging tasks are performed by some old friends: from dcm4che.org come the dcm4chee image server, dcm4che2 toolkit and Weasis web viewer, there is the DCMTK DICOM toolkit from OFFIS, and Erik Nolf’s XMedCon for image format conversion. Other projectss provide the non image-related infrastructure: (VirtualBox virtualization, PostgreSQL database, JBoss application server, Play web framework).
MRIdb is a useful program for those managing imaging studies. As supplied, it runs with just a few clicks, and has full control for those wishing to get more involved in the technical details. The implementation as a fully-configured virtual machine makes this of particular interest for those who’ve never run their own image store. Give it a try: in five minutes you can be sending images to and from your very own PACS!