DICOM PS3.17 2019a - Explanatory Information

IIII.2 Example of Fused CT/MR Derived Encapsulated STL

In this example, the patient will shortly be undergoing a complex cardiac surgery. A 3D manufacturing model (encoded in binary STL) was created to manufacture a surgical planning aid representing the patient's unique anatomy.

To begin, a series of CT images (CT-02) and a series of MR images (MR-01) were registered using CT-02's frame of reference as the base coordinate system and then fused. An initial version of the model was derived and reviewed by the surgical team who requested that some of the anatomy surrounding the heart be removed. A second version of the model was created on July 16, 2017 at 1:04:34 PM then stored in a DICOM instance at 1:33:01 PM. The CT and MR data were acquired at earlier dates.

The Encapsulated STL file shown in this example is the second version..

Both versions of the STL were created in the coordinate system of CT-02; so they all share the same Frame of Reference value.

Note: Mapping to other Frames of Reference of secondary source series would be handled via registration objects.

A preview image (optional) showing the rendered 3D object was created and included with the encapsulated STL as an icon image.

The creator of the model inscribed the patient's medical record number on a side of the model to avoid the possibility of a wrong patient error.

Table IIII.2-1. Fused CT/MR Derived Encapsulated STL Example

Attribute Name

Tag

Example Value

Comments

<Patient and General Study Modules not shown for brevity>

Modality

(0008,0060)

M3D

Series Instance UID

(0020,000E)

2.999.89235.5951.35894.0086

Series Number

(0020,0011)

6

Series Description

(0008,103E)

3DP Models

Instance Number

(0020,0013)

2

Frame of Reference UID

(0020,0052)

1.2.3.4.5.6.777.0.1

Manufacturer

(0008,0070)

Acme Additive Inc

Manufacturer's Model Name

(0008,1090)

Cardioplan

Device Serial Number

(0018,1000)

10065789

Software Versions

(0018,1020)

6.3

Content Date

(0008,0023)

20170716

Content Time

(0008,0033)

130034

Acquisition DateTime

(0008,002A)

20170716130034

Image Laterality

(0020,0062)

U

Burned In Annotation

(0028,0301)

YES

Recognizable Visual Features

(0028,0302)

NO

Source Instance Sequence

(0042,0013)

A sequence referencing CT-02 and MR-01 source images because both were used.

%item

>Referenced SOP Class UID

(0008,1150)

1.2.840.10008.5.1.4.1.1.2.1

Referenced object is an Enhanced CT Image Storage Instance

>Referenced SOP Instance UID

(0008,1155)

2.999.89235.5951.35894.153

The multi-frame CT instance from study CT-02

>Purpose of Reference Code Sequence

(0040,A170)

(121324, DCM, "Source image")

CID 7060 “Encapsulated Document Source Purposes of Reference”

%enditem

%item

>Referenced SOP Class UID

(0008,1150)

1.2.840.10008.5.1.4.1.1.4.1

Referenced object is an Enhanced MR Image Storage Instance

>Referenced SOP Instance UID

(0008,1155)

2.999.89235.5951.35894.154

The multi-frame MR instance from study MR-01

>Purpose of Reference Code Sequence

(0040,A170)

(121324, DCM, "Source image")

CID 7060 “Encapsulated Document Source Purposes of Reference”

%enditem

Document Title

(0042,0010)

Mixed Modality 3D CAM model

Concept Name Code Sequence

(0040,A043)

(129019, DCM, "Mixed Modality 3D CAM model")

CID 7061 “Model Document Titles”

Predecessor Documents Sequence

(0040,A360)

A reference to the earlier encapsulated STL

%item

>Study Instance UID

(0020,000D)

2.999.1241.1515.15151.515.62

>Reference Series Sequence

(0008,1115)

%item

>>Series Instance UID

(0020,000E)

2.999.89235.5951.35894.151

>>Referenced SOP Sequence

(0008,1199)

%item

>>>Referenced SOP Class UID

(0008,1150)

1.2.840.10008.5.1.4.1.1.104.3x

Encapsulated STL SOP Class

>>>Referenced SOP Instance UID

(0008,1155)

2.999.1241.1515.15151.515.68

%enditem

>>Purpose of Reference Code Sequence

(0040,A170)

(129010, DCM, "Edited Model")

CID 7062 “Purpose of Reference to Predecessor 3D Model”

%enditem

%enditem

MIME Type of Encapsulated Document

(0040,0012)

model/stl

Encapsulated Document

(0042,0011)

<Byte stream representing the binary STL file>

Note that ASCII STL files are not supported.

Content Description

(0070,0081)

Pre-surgery cardiac model from CT and MR

Measurement Units Code Sequence

(0040,08EA)

(mm, UCUM, "mm")

Model Modification

(0068,7001)

NO

Model Mirroring

(0068,7002)

NO

Model Usage Code Sequence

(0068,7003)

(129013, DCM, "Planning Intent")

CID 7064 “Model Usage”

In this example, the goal is to help plan the surgery, so the value is "Planning Intent".

Icon Image Sequence

(0088,0200)

Sequence containing the pre-rendered preview image

%item

<Content of Table C.7-11b "Image Pixel Macro Attributes" not shown>

%enditem

SOP Class UID

(0008,0016)

1.2.840.10008.5.1.4.1.1.104.3

SOP Instance UID

(0008,0018)

2.999.1241.1515.15151.515.987

Instance Creation Date

(0008,0012)

20170716

Instance Creation Time

(0008,0013)

133301


DICOM PS3.17 2019a - Explanatory Information