Trial Wire – Organizing DICOM Images in a Disorderly World

IXICO recently made available for free a tool called Trial Wire. This is a tool that is routinely used by us in-house to transfer medical image files between clinical trial sites and IXICO servers. Nearly all medical imaging scanners in hospitals can store and transfer image files as a series of slices, or cross sections, using the industry-standard DICOM format. DICOM stands for digital imaging and communications in medicine. It was adopted by the medical imaging community to allow for ease of communication and data transfer, independent of the manufacturer or type of scanner involved. You can think of DICOM as the medical imaging field’s equivalent of a .pdf file.

The DICOM format is designed for communication of image data between scanners, imaging workstations, and hospital image archive (known as Picture Archival and Communication Systems or PACS). But for research studies and clinical trials, handling of DICOM data can be painful!
Among several clever features of Trial Wire, one that is sometimes overlooked is its ability to organize DICOM files into series of sub-directories. This seemingly trivial feature is in fact very complicated for most DICOM data users.

The problem lies with the imaging systems and equipment that are made by the likes of GE, Siemens, and Philips. When a patient is given an MR or CT scan, say, the imaging system can transmit the images to a computer in either a random or systematic fashion. Although the images are still fully DICOM compliant, the manufacturers do not have a standard way of organizing the data. This can result in several image slices being stored in dozens of sub-directories in what to many users can be a very confusing fashion. To manually structure the images is tedious and time-consuming.

Trial Wire uses an algorithm that is able to specifically tackle this problem. When a directory is specified, Trial Wire searches that particular directory and any sub-directory for any DICOM data. It then automatically imposes a directory structure into one of the three options set by the user:

1. Subject/Study/Series
   In this structure, the data is organized first by subject (which can be de-identified by Trial Wire) then by study name and then by image series. This allows for easy review in a trial-centric manner, meaning that someone interested in retrieving the data can now easily search by subject, study, or series. This approach will generally appeal most to those conducting clinical trials.
2. Flat directory
   In this structure, all the files are copied into one target collection. They are also all renamed to have a unique 8-character filename and a DICOMDIR file is created to describe them. This approach will most often be used by those who want to maintain large volumes of data that can be further organized later according to changing needs.
3. Mirror the original structure
   The original directory structure will be kept. This also means that any name on the files (which may contain personal information) is kept. This approach will most likely be used in a clinical setting where patient data is a necessary part of communication between physicians, such as conferring physicians within a hospital centre.

The organizing feature offered by Trial Wire gives the option to structure its files the way our experts do it here at IXICO or preserve the original structure. This provides the maximum flexibility for end users to organize DICOM data for storage or transfer. And a key benefit is that data from different scanners can all be stored together in a coherent structure to allow for easier sharing and analysis of the data.