GE Medical Systems1 Charles Parisot May 5, 2002 GE Medical Systems DICOM Supplement 49 Extended MR DICOM Objects Korean PACS Conference

GE Medical Systems2 New MR Image Objects …… Why ? To address with full interoperability, add acquisition techniques such as : Diffusion Imaging, Perfusion Imaging, Angio Imaging, fMRI Imaging, Cardiac Imaging and Spectroscopy for MR

GE Medical Systems3 3 New MR Image Objects DICOM Supplement 49 Raw Image Data Object standardized enough to allow network, archive otherwise vendor dependent Enhanced MR Image Object MR Spectroscopy Object

GE Medical Systems4 A new Generation of Image Objects …… Why ? More complex inter-relation between these images Performance and ease to manage the Exploding number of images in an MR acquisition Real-Time Imaging increasingly used

GE Medical Systems5 A new Generation of Image Objects …… Why ? More complex inter-relation between these images Performance and ease to manage the Exploding number of images in an MR acquisition Real-Time Imaging increasingly used Solution: Concatenation of Multiframe Image Objects

GE Medical Systems6 MR Multiframe High Level Requirements Provide a way of efficiently organizing large groups of images (1,000 to 10,000 Images) Provide a way of organizing any group of images (cine loop, Peripheral Vascular stations/phases) Allow for organizing of image sets associated with a single complex multiphase application (Peripheral Vascular localizers, stations/phases) Dynamic Images with up to 100 dimensions !

GE Medical Systems7 Multiframe Organization Flexible separation of Static vs Dynamic Attributes Always Static Attributes - They never change per frame in a multiframe: –Will never need to change within an Image Object => changes in these require the start of a new Image Object –Goal is to reduce complexity in receiving application –Facilitates use of current toolkit technology. Examples: Pixel (# bits, matrix size, etc.) Pulse Sequences

GE Medical Systems8 Multiframe Organization Dynamic Attribute Groupings Dynamic Attributes may change per frame in a multiframe. They are separated in Functional Groups that often change together: –To reduce the number of changeable entities within a multiframe object –to allow for modality independent reuse – modality independent vs dependent –to convey semantics to the receiving application e.g., MIP program may not accept a MF object that has an orientation group that changes –Special care has been taken to "balance" the size of groupings.

GE Medical Systems9 MR Multiframe Organization – 24 Dynamic Functional Groups Pixel Measures Frame Content Plane Position Plane Orientation Referenced Image Derivation Image Cardiac Trigger Frame Anatomy Pixel value Transformation Frame VOI LUT Real World Value Mapping MR Image Frame Type MR Timing & Related Parameters MR FOV/Geometry MR Echo MR Modifier MR Image Modifier MR Receive Coil MR Transmit Coil MR Diffusion MR Averages MR Spatial Saturation MR Metabolite Map MR Velocity Encoding

GE Medical Systems10 MR Multiframe Organization – 24 Dynamic Functional Groups Pixel Measures Frame Content Plane Position Plane Orientation Referenced Image Derivation Image Cardiac Trigger Frame Anatomy Pixel value Transformation Frame VOI LUT Real World Value Mapping MR Image Frame Type MR Timing & Related Parameters MR FOV/Geometry MR Echo MR Modifier MR Image Modifier MR Receive Coil MR Transmit Coil MR Diffusion MR Averages MR Spatial Saturation MR Metabolite Map MR Velocity Encoding For a Specific MR Image Instance : some Functional Groups are shared across all frames, some vary per frame Per Frame Functional Group Sequence Frame 1 attributes Frame 2 attributes Shared Functional Groups Attributes For all frames MR Image Instance

GE Medical Systems11 A new Generation of Image Objects …… Why ? More complex inter-relation between these images Performance and ease to manage the Exploding number of images in an MR acquisition Real-Time Imaging increasingly used Solution: Concatenation of Multiframe Image Objects

GE Medical Systems12 Reasons to break up MultiFrame Objects File systems file, partitions, or storage media size limits To provide pseudo real-time streaming (fMRI from scanner to workstation for real-time monitoring and processing) To provide for retransmission in chunks in the case of network transmission failures Standard “Forced Breakup” due to dynamic attribute being defined as a static attribute

GE Medical Systems13 Concatenations An object may be split up into two or more SOP Instances 2 34 n Pixel data for frames of set n Concatenation Frame Offset Number (e.g.1, 2001, 4001 and 4201) Shared Dimension Module attributes Image attributes 1 e.g. After frame-numbers 2000, 4000 and

GE Medical Systems14 Concatenation of MF Objects Examples: total body scan stations, fMRI broken into time segments Concatenation UID is used to group image objects belonging to the same concatenation All concatenated objects must have the same: –Instance Number –Frame of reference –Series number & UID –Dimension modules

GE Medical Systems15 A new Generation of Image Objects …… Why ? For A Higher Level of Compatibility Most attributes are made mandatory for greater interoperability Many old attributes not used removed Anatomy specification required to facilitate PACS handling Image Relationship & Referencing – generalized and added coded reasons for reference New image pipeline (LUT and Color Palette) Image Types One sacrifice: Create a New Enhanced MR Image Object, different and incompatible with the existing MR image Object

GE Medical Systems16 MR Object Relationships

GE Medical Systems17 LUTs

GE Medical Systems18 Real World Value LUT Sometimes the integer pixel values and what the user wants to see for pixel values based on real world units (such as blood flow velocity at a pixel location) are different. The Real World Value LUT maps the pixel data to the units the user wants to see (cm/sec or mm/sec…) Multiple overlapping regions of pixel values can be mapped to multiple LUTs including regions that are not mapped at all (e.g. functional data versus physiological data).

GE Medical Systems19 Palette Color Pipeline

GE Medical Systems20 Palette Color LUT Palette Color LUT is used to map Monochrome2 pixels to color Mixed Monochrome2 grayscale pixels and palette color pixels can be shown in the same image (e.g. to show functional data in color on top of physiological data). Only a single grayscale and single color range of pixel values can be represented.

GE Medical Systems21 Image Type Attributes MR Image Description Macro MR has a large, rich set of image types Applications need a way to determine if an image set is compatible with its processing Supplement 49 proposes a reasonably orthogonal set of attributes for image type useful to reading applications: Image Type (0008,0008) values: –1: Original/Derived – redefined –2: Primary/Secondary – Only Primary valid for MR –3: Image Flavor – the overall most important characteristic of this Image – e.g. flow encoded, max-IP, Perfussion, Stress, T1, T2, etc. –4: Derived Contrast – Diffusion aniso, Subtraction, Velocity, None – generally an indication of post processing performed

GE Medical Systems22 Image Type Attributes – 2 MR Image Description Macro Other Image Types are separate attributes: –Pixel Presentation – (Palette) Color/Monochrome (color supported or not) –Volumetric Properties – Volume, Sampled, Distorted (used by Grx, 3D to determine image compatibility with the application) –Volume Based Calculation Technique – MAX_IP, MPR, Curved-MPR… (used by Grx, 3D to determine image compatibility) –Complex Image Component - Magnitude, Phase, Real, Imaginary (standard MR transformations of the raw data) –Acquisition Contrast - T1, T2, Perfusion, Combination… (MR acquisition contrast types)

GE Medical Systems23 New MR Image Objects …… Why ? To address with full interoperability add acquisition techniques such as : Diffusion Imaging, Perfusion Imaging, Angio Imaging, fMRI Imaging, Cardiac Imaging and Spectroscopy for MR Each Application has specific viewing characteristics…..

GE Medical Systems24 Order in Viewing ? Many parameters can change from frame to frame. For the most important, those that define certain relations between slices, specific tags have been defined to indicate and order the relation. A “dimension” will consist of “number of...” tags with the highest ordinal number of every dimension. Sorting images according to those ordinal numbers, and repeating that for another dimension, will enhance receiving applications and interoperability

GE Medical Systems25 Dimension Attributes Examples Stations Stacks Positions In-stack slice Position (slice # relative to stack) Orientations Trigger delay times Temporal positions Diffusion B values Metabolite maps Echoes

GE Medical Systems26 Examples can be given in many area’s, but in general the mechanism uncouples the actual value of a certain attribute: actual position vs. position number In some cases the increase of attribute values will be related to that of the index number: e.g. “Trigger delay time” (in ms) increases with the Trigger delay time index: In other cases these are completely uncoupled: Orientation(patient) and Orientation Index In some cases the index looks very much like the attribute value. Dimensions – Use of Indexes

GE Medical Systems27 position time b-value cardiac phase volume orientation time Examples of properties that may change,

GE Medical Systems28 time Trigger delay time index Cardiac Example: 1 station, 1 stack, n trigger delay times Instack Index Frame number 1-6 Frame number 13-18Frame number 7-12

GE Medical Systems29 time B-value Index Diffusion Example: 1 station, 1 stack, 3 b-values Instack Index Frame number 1-6 Frame number 13-18Frame number 7-12

GE Medical Systems30 Example: 1 Station, 3 stacks

GE Medical Systems31 Stack 1 Stack 2 Stack 3 Multi Stack example (parallel and non-parallel, 2D and 3D) Frame number 1-6 Frame number 7-12 Frame number Instack Index

GE Medical Systems32 A new Generation of MR Image Objects Multiframe Concatenation Functional Groups of Dynamic Attributes Most attributes mandatory Anatomy specification required LUT for Real Values and Color Maps MR Object Relationship and Referencing Dimensions and Indexes New Enhanced MR Image MR Spectro Raw Images Advanced MR Applications Higher Efficiency Higher Compatibility And soon Enhanced CT…..

GE Medical Systems33 DICOM Web Site medical. nema. org