Enhanced CT-MR Profile - Brief Proposal

IHE Profile Proposal (Brief)

Proposed Profile: Enhanced MR/CT Image

• Proposal Editor: Cor Loef/Dick Donker
• Date: 2007-08-23
• Version: 0.1
• Domain: Radiology

The Problem

The existing DICOM CT and MR objects needed a significant revision because of technology advancements in CT and MR technology, and new acquisition protocols. DICOM has published the specification for enhanced multi-frame MR and CT images, in 2003 and 2004.

The creation of these new enhanced objects in CT and MR modalities in real products has started, and this requires storage in the PACS, and the consistent hanging and display on workstations for the multitude of clinical acquisition protocols supported by these objects.

There exists however a real risk that the various modality vendors will select a slightly different encoding in these complex objects for the same clinical setting, and consequently the workstation vendors will be confronted with these variations. This may well result in inconsistencies when hanging and displaying these objects for a certain clinical use case. Users will be annoyed by these unnecessary viewing differences, and interoperability is at risk.

A profile that specifies the necessary key encoding of critical concepts in the enhanced CT/MR objects for particular clinical use cases would greatly simplify the task of configuring hanging protocols during PACS and modality installation, and reduce the unnecessary and unwanted variance between sites.

Key Use Case

The Advanced CT/MR Taskforce has defined key clinical use cases for a demonstration at RSNA 2005:

• CT/MR CARDIAC IMAGING

New CT/MR cardiac images containing standard attributes for location and timing information.

• MR DIFFUSION

MR diffusion images containing standard attributes for diffusion B values, direction and diffusion image type.

• CT/MR CONTRAST PERFUSION

Intra-venous contrast enhanced images containing standard attributes for timing and phase.

• MULTI-STACK SPINE IMAGING

Images are acquired at multiple disk space levels of the spine such that multiple slices at each level are parallel to the disk space, each in a separate stack from slices at different angles through other disks. These images are exchanged in an interoperable way with standard attributes describing the stacks and their geometries.

• MR SPECTROSCOPY

Single-voxel, multi-voxel or multi-slice 1D MR spectra are exchanged with reference and metabolite images that contain information to allow correct display, post-processing and analysis.

These use cases may constitute the basis for a new IHE CT/MR Image profile, which specifies for each all that are applicable of the following:

• The required attributes (mostly already defined in the standard),
• The relevant functional grouping
• The content of the dimension module
• The use of a Real World Values LUT
• The use of a Supplemental Color LUT
• The relevant attributes for display on a workstation

Standards & Systems

The systems involved are the Acquisition Modality, Image Manager/Archive and the Image Display. The standards involved are the DICOM 2006: Enhanced MR Image, MR Spectroscopy and Enhanced CT Image (multi-frame) objects.

Discussion

The NEMA Committee for the Advancement of DICOM would like to organize a first informal testing of this profile with systems that envisage or already give support for enhanced CT and MR objects at the January 2008 connectathon.