Supplement 188 Multi-Energy CT Imaging DICOM Working Group 21 - - PowerPoint PPT Presentation

▶
supplement 188
SMART_READER_LITE
LIVE PREVIEW

Supplement 188 Multi-Energy CT Imaging DICOM Working Group 21 - - PowerPoint PPT Presentation

Dec 17, 2022 1.4k likes •1.52k views

DICOM Supplement 188 Multi-Energy CT Imaging DICOM Working Group 21 Computed Tomography Rationale Short introduction of Multi Energy (ME) Images Overview: Imaging techniques, including scanning, reconstruction, processing, when the

slide-1
SLIDE 1

DICOM Supplement 188 Multi-Energy CT Imaging

DICOM Working Group 21 Computed Tomography

slide-2
SLIDE 2

Rationale

Short introduction of Multi Energy (ME) Images

Overview:

  • Imaging techniques, including scanning, reconstruction, processing, when the scanner utilizes

multiple energies from the X-Ray beam spectrum, as opposed to the conventional CT imaging, when a single (accumulated) X-Ray spectrum is used.

  • The existing CT and Enhanced CT (eCT) IODs do not adequately describe the new CT multi-

energy imaging. Although different vendors apply different scanning and detection techniques to achieve multi-energy images, there is large commonality in the generated diagnostic images.

Goals for ME Image implementation:

  • provide new essential ME information (acquisition, reconstruction and processing attributes) within

the IOD.

  • facilitate fast and easy adoption of standard based ME imaging across the imaging community,

both modalities and PACS/Displays.

  • address (or at least to minimize) the risk of mis-interpretation when the ME images are displayed

by a display does not support the new attributes of the ME-image, including incorrect measurements

  • adapt existing attributes of the CT / Enhanced CT IOD to fit ME techniques.

2

slide-3
SLIDE 3

Virtual Mono- energetic Image (VMI) Material- Specific Image Color Overlay Image Color Blending Image Discrete Labeling Image Effective Atomic Number (Z) Image Electron Density Image Probability Map Image Color Map Image

Multi Energy Imaging Material Quantification Family Material Labeling Family Material Visualization Family

Standard CT Image

Objective Image Family

Iodine Map; Bone Density

Overview

Proportional Map Image Value based Map Image Material- Modified Image

Gout crystals Highlighted; Partially- Suppressed

Material- Removed Image

  • Virt. Non-

Contrast;

  • Virt. Non-Ca;

CT IOD Other IOD

slide-4
SLIDE 4

Organization Structure

Multi-energy CT Macro (new added to CT IODs)

  • Multi-energy Flag (Y/N)
  • Multi-energy CT Acquisition Sequence (1C, 1 item)
  • Multi-energy CT Acquisition Sequence (1-N)

– Multi-Energy Source Technique – Multi-Energy Detection Technique – Other ME-specific attributes – Common CT Acquisition Macro

  • Multi-energy CT Processing Sequence (1C, 1 item)
  • Decomposition Method
  • Decomposition Basis Sequence (2-N items, one for each basis)
  • Other decomposition attributes
  • Multi-energy CT Characteristics Sequence (1C)
  • Monochromatic Energy Equivalent (for Virtual Monochromatic Image)
  • Multi-energy Quantification CT Image Macro

– Specific Material Code Sequence – Material Modification Sequence

  • Multi-energy Labeling CT Image Sequence (1 item)

– Material Labeling Type – Material Modification Sequence 4

slide-5
SLIDE 5

X-Ray Source

Generating different X-Ray Energies: KVP

Scanned Object Detector

Filter Other Parameters Discriminating Energies: Multiple Layers Photon Counting

Multi-Energy CT Acquisition Techniques

Methods to separate at least two energies include

– Multiple Scans of the same area with diff parameters – Multiple X-Ray Sources and/or Detectors – Switch KVP during the rotation – One source with Multi-Layer Detector – One source with Photon Counting Detector

slide-6
SLIDE 6

“Objective” Images

Virtual Monochromatic Effective Atomic Number Electron Density

Described in ME CT Characteristics Sequence (currently just keV for VMI)

Data Acquisition Decomposition to Base Components

Described in ME CT Processing Sequence Described in ME CT Acquisition Sequence

A1 A2 M1 M2 Mn

…

An

…

Generation of Diagnostic images

slide-7
SLIDE 7

“Material” Images

Data Acquisition

A1 A2

Described in ME CT Processing Sequence Described in ME CT Acquisition Sequence

Material Labeling Family

Described in ME CT Characteristics Sequence

Material Quantification Family

M1 M2 Mn

Material Visualization Family

Decomposition to and/or Classification of two or more Materials

…

An

…

Generation of Diagnostic images

slide-8
SLIDE 8

Material Images Generation

M1 M2

Material-Specific Image

May be ignored / Not described

M1 M2 Mn

Conventional CT or VMI Image Material Visualization Images

  • Subtract
  • Suppress
  • Highlight
  • Compensate
  • Recalculate

Mn

Material Labeling Images Proportional Map Image Material- Removed Image

Examples::

  • Iodine Map
  • Bone (Ca) Density Map

Examples::

  • Virtual Non-Contrast : COMPENSATED
  • Virtual Non-Calcium : COMPENSATED
  • Bone or Uric Acid Removed :

SUBTRACTED (0) Examples::

  • Tendon Enhancement: HIGHLIGHTED
slide-9
SLIDE 9

Material Labeling Images

2 0: None 1: Material A 2: Material B 3: Material C Discrete Labeling (most-probable material): Material A = 0-15 Material B = 10-20 Material C = 18-50 Material A BCD

0.3

Proportional:

contains 30% of material A 20% chance containing material A

0.2

Probability:

4

Value based:

20 10 15

Material A BCD

slide-10
SLIDE 10

“Visualization” Images Color Overlay

A B

A) A CT image that is windowed to highlight a particular material with a color map applied. It also may have a translucency applied to be able to see the image underneath. (E.g. Iodine image, Effective Z image) B) A structural image showing the anatomical structure. (E.g. Monochromatic image) C) The result image (combined information e.g. Secondary Capture, Blending, …)

C Blended Image Structural Image Overlay Image