DICOM Conformance

DICOM Conformance Statement
for ExactVu™ 2.0

 

Conformance Statement Overview


This is a DICOM Conformance Statement for ExactVu 2.0.  ExactVu provides the capability to store ultrasound studies to a PACS server, and read MR images from a USB storage device, or a CD/DVD through a USB port. It supports the following DICOM SOP classes:


SOP Class Name

SOP Class UID

Service Class Role

Verification(Echo)

1.2.840.10008.1.1

SCU

US Image Storage

1.2.840.10008.5.1.4.1.1.6.1

SCU

Raw Data Storage

1.2.840.10008.5.1.4.1.1.66

SCU

Storage Commitment Push Model

1.2.840.10008.1.20.1

SCU

ExactVu serves as DICOM File-Set Reader (FSR); however, it only reads MR studies with DICOMDIR for its FusionVu functionality.

 

1 Introduction

1.1 Audience

This DICOM Conformance Statement is intended for following audiences:

  • Hospital or clinical practice staff or Exact Imaging customers
  • System integrator of medical equipment
  • DICOM Software engineer or designer
  • Marketing or Sales personnel with DICOM knowledge

1.2 Scope and field of Application

It is the intent of this document to provide an unambiguous specification for DICOM implementations of ExactVu. This specification includes a DICOM Conformance Statement and is necessary to ensure proper processing and interpretation of ExactVu medical data exchanged using DICOM.

The reader of this DICOM Conformance Statement should be aware that ExactVu uses private data elements to hold its raw data.  The reader is advised to ignore these elements as they are private tags only.

The use of the DICOM Conformance Statement, in conjunction with the DICOM Standards, is intended to facilitate communication with the ExactVu high resolution micro-ultrasound system. However, by itself, it is not sufficient to ensure that inter-operation will be successful.

The reader of this DICOM Conformance Statement should be aware of the following important issues:

  • Test procedures should be defined and conducted to validate the desired level of connectivity
  • The DICOM standard will evolve over time to meet future real-world requirements

1.3 Definition, Terms and Abbreviation

Definitions, terms and abbreviations used in this document are defined within the different parts of the DICOM standard. Abbreviations and terms used are as follows:

Term

Definition

EVu

High-resolution micro-ultrasound device from Exact Imaging Inc.

AE

DICOM Application Entity

ASCE

Association Control Service Element

FSR

File-Set Reader

IOD

Information Object Definition

ISO

International Standard Organization

PDU

Protocol Data Unit

SCU

Service Class User

SCP

Service Class Provider

SOP

Service-Object Pair

GSPS

Grayscale Softcopy Presentation State

TCP/IP

Transmission Control Protocol/Internet Protocol

UID

Unique Identifier  

2 Networking

2.1 Implementation Model

ExactVu implements DICOM verification SCU, Storage SCU and Storage Commitment SCU.  Below is the application data flow diagram.


Figure 1: DICOM Standard Interface

2.2 Functional Definition of Application Entities

All communications and image transfer with remote application is accomplished using the
DICOM protocol over a network using the TCP/IP protocol stack.

2.2.1 Verification

The DICOM verification SCU (i.e., connectivity test) is available for test and validation purposes of remote AEs.  ExactVu opens an association and sends C-ECHO request to verify specified DICOM SCP node. Upon receiving the response from SCP, or in case of failure, it closes the connection.

2.2.2 Storage and Storage Commitment

DICOM Storage SCU and Storage Commitment SCU are available to send studies to remote AEs.  When the user selects a study or studies to export to PACS, ExactVu wraps the images of a study as DICOM standard ultrasound or raw data SOP instances, document according to 2.3.4.2.3 and Appendix A, and sends the SOP instances to the Storage SCP.

It will then request to SCP a Push-Model Storage Commitment for the set of the SOP instances if the Storage Commitment is configured to use.  As a Storage Commitment SCU, ExactVu establishes an association to send a Storage Commitment request (N-ACTION) to the remote AE, gets the response status and the association is done.  It then waits 30 seconds for an association from the SCP to get the commitment status for every SOP instance sent from the SCP with an N-EVENT-REPORT.

2.3 AE Specifications

2.3.1 SOP Classes

ExactVu AE provides the Standard Conformance to the following DICOM Standard SOP Classes as SCU.

SOP Class Name

SOP Class UID

Service Class Role

Verification(Echo)

1.2.840.10008.1.1

SCU

US Image Storage

1.2.840.10008.5.1.4.1.1.6.1

SCU

Raw Data Storage

1.2.840.10008.5.1.4.1.1.66

SCU

Storage Commitment Push Model

1.2.840.10008.1.20.1

SCU

2.3.2 Transfer Syntaxes

Transfer Syntax UID

Implicit VR Little Endian

1.2.840.10008.1.2

Explicit VR Little Endian

1.2.840.10008.1.2.1

2.3.3 Association Establishment Policies

2.3.3.1 General

ExactVu always proposes the DICOM Application Context Name listed in the table below during the establishment of all associations. The maximum PDU size is 64234 bytes.

Name UID

DICOM 3.0 Application Context

1.2.840.10008.3.1.1.1

2.3.3.2 Number of Associations

This version of implementation supports one simultaneous association for initiator and acceptor.

2.3.3.3 Asynchronous Nature

This version of implementation only supports a single outstanding transaction over an existing association. As such, it does not support asynchronous communication.

2.3.3.4 Implementation Identifying Information

ExactVu uses the MergeCOM-3 Advanced DICOM Toolkit. It uses the following implementation identifying parameters:

Implementation Class UID        2.16.840.1

 

Implementation Version           MergeCOM3_5_4_0

 

2.3.4 Association Initiation Policy

ExactVu initiates associations for the following real-world activities:

  • Verification(C-ECHO) SCU
  • Storage(C-STORE) SCU
  • Storage Commitment Push Model SCU

2.3.4.1 (Real-World) Activity - Verification SCU


2.3.4.1.1. Description and Sequence

ExactVu initiates a verification request when the user tests DICOM connectivity from the UI or prior to sending a study.  The association is closed when a response from SCP is received or in case of failure.


2.3.4.1.2 Proposed Presentation Contexts

Abstract Syntax

Transfer Syntax

Role Extended Negotiation

Name

UID

Name

UID

 

 

Verification

1.2.840.10008.1.1

Implicit VR Little Endian

1.2.840.10008.1.2

SCU

None

Explicit VR Little Endian

1.2.840.10008.1.2.1

SCU

None

Explicit VR Big Endian

1.2.840.10008.1.2.2

SCU

None


2.3.4.1.3 SOP Specific Conformance Statement for SOP Verification Class

ExactVu provides standard conformance for DICOM communication verification.


2.3.4.2 (Real-World) Activity - Storage SCU



2.3.4.2.1 Description and Sequence

ExactVu initiates a C-STORE association as SCU when attempting to send SOP Instances to remote AEs. The transfer syntaxes that can be proposed are normally determined using the table in section 2.3.4.2.2.


2.3.4.2.2 Proposed Presentation Contexts

Abstract Syntax Transfer Syntax Role Extended Negotiation

Name

UID

Name

UID

 

 

Ultrasound Image Storage

Raw Data Storage

1.2.840.10008.5.1.4.1.1.6.1

 

1.2.840.10008.5.1.4.1.1.66

Implicit VR Little Endian

1.2.840.10008.1.2

SCU

None

Explicit VR Little Endian

1.2.840.10008.1.2.1

SCU

None

Explicit VR Big Endian

1.2.840.10008.1.2.2

SCU

None

2.3.4.2.3 SOP Specific Conformance Statement for SOP Classes

ExactVu provides standard conformance to the DICOM Standard Storage Service Class as SCU for all storage SOP classes listed in the table in section 2.3.4.2.2 .  ExactVu sends the following attributes in C_STORE_RQ. All the mandatory attributes are sent.  ExactVu also uses private attributes (refer to Appendix A ).

     

0008

0005

Specific Character Set

0008

0008

Image Type

0008

0016

SOP Class UID

0008

0018

SOP Instance UID

0008

0020

Study Date

0008

0021

Series Date

0008

0022

Acquisition Date

0008

0023

Content Date

0008

0030

Study Time

0008

0031

Series Time

0008

0032

Acquisition Time

0008

0033

Content Time

0008

0050

Accession Number

0008

0060

Modality

0008

0070

Manufacturer

0008

0080

InstitutionName

0008

0090

Name of the patient's referring physician

0008

0201

Time zone offset from UTC

0008

103E

Series Description

0008

1090

Manufacturer's Model Name

0010

0010

Patient's Name

0010

0020

Patient ID

0010

0021

Issuer of Patient ID

0010

0030

Patient's Birth Date

0010

0040

Patient's Sex

0020

000D

Study Instance UID

0020

000E

Series Instance UID

0020

0010

Study ID

0020

0011

Series Number

0020

0013

Instance Number

0028

0002

Samples per Pixel

0028

0004

Photometric Interpretation

0028

0006

Planar Configuration

0028

0010

Rows

0028

0011

Columns

0028

0030

Pixel Spacing

0028

0100

Bits Allocated

0028

0101

Bits Stored

0028

0102

High Bit

0028

0103

Pixel Representation

7FE0

0010

Pixel Data

2.3.4.3 (Real-World) Activity – Storage Commitment Push Model SCU

2.3.4.3.1 Description and Sequence

ExactVu supports synchronous mode for Storage Commitment Push Model SCU after the previous C-STORE SCU operation for a study: ExactVu sends an N-ACTION-RQ request with the SOP instances that need to be committed to the remote AE, then listens to its local port (which needs to be configured together with the local IP or hostname on the SCP) for N-EVENT-REPORT-RQ to receive the commitment result of SOP instances. The timeout for waiting is for 30 seconds. The presentation contexts are defined in section 2.3.4.3.2 .

2.3.4.3.2 Proposed Presentation Contexts

Abstract Syntax Transfer Syntax Role Extended Negotiation

Name

UID

Name

UID

 

 

Storage Commitment Push Model

1.2.840.10008.1.20.1

Implicit VR Little Endian

1.2.840.10008.1.2

SCU

None

Explicit VR Little Endian

1.2.840.10008.1.2.1

SCU

None

Explicit VR Big Endian

1.2.840.10008.1.2.2

SCU

None

2.3.4.3.3 SOP Specific Conformance Statement for SOP Verification Class

The associated real-world activity with the Storage Commitment Push Model service is the communication by the ExactVu to remote AE so that the SCU requests the SCP to commit to permanently store SOP Instances that have been sent to it.  Once the all the SOP instances in a study are committed on the SCP, ExactVu can mark the study as successfully archived and it can be deleted from local storage.

2.3.5 Association Acceptance Policy

As a Storage Commitment Push Model SCU, ExactVu waits for association from the SCP. It may reject Association attempts with rejected-transient and no-reason-given whenever any of the following error happens:

  • Invalid association
  • No pending request for the association
  • Unexpected system error
  • The association has been aborted by the remote AE

2.4 Network Interfaces

2.4.1 Physical Network Interfaces

ExactVu uses the MergeCOM-3 Advanced DICOM Toolkit to communicate over the TCP/IP protocol stack on any physical interconnection media supporting the TCP/IP stack. The Toolkit inherits the TCP/IP stack from the host operating system upon which it executes, i.e., Windows 7 for ExactVu.

2.4.2 Additional Protocols

Not applicable.

2.5 Configuration

Any implementation's DICOM conformance may be dependent upon configuration, which takes place at the time of installation.

2.5.1 AE Title/Presentation Address Mapping

AE Titles on ExactVu can be configured from Preferences/Network Settings page.  The parameters and default values are specified as following:

Service Class Name Remote Server (IP or Host Name) Remote Port Remote AE Local AE Local Port

Storage

 

104

 

 

Not applicable

Storage Commitment Push Model

 

104

 

 

105

Note:

  1. Empty items in the above table means there is no default value.
  2. The parameters specified in the above table are on the ExactVu side, which acts as an SCU. These parameters must match the corresponding parameters set in the DICOM server, i.e., the SCP. This means:
    • The remote server (SCP) and its port should be able to be connected to ExactVu.
    • The remote AE should be correctly set in the SCP.
    • The local AE from ExactVu should be allowed for the service class in the SCP.
    • The local port (and the local computer name or address) for Storage Commitment Push Mode should be known for the service class in the SCP.

3 Media Interchange

3.1 Implementation Model

ExactVu implements DICOM File-Set Reader. 

3.1.1 Application Data Flow Diagram


Figure 2: DICOM File-Set Reader Flow Diagram

3.1.2 Functional Definitions of AEs

ExactVu imports images and Presentation States from a removable media storage. The real-world activity “Import DICOM Objects from Media” is performed when the user requests to read a MR study list and/or images from a CD/DVD or USB storage device.

3.1.3 Sequencing of Real World Activities

When the user selects to display MRI study list from a USB based CD/DVD drive, or from a USB storage device, ExactVu acts as a FSR to read the DICOMDIR from the DICOM file set on the media, i.e., CD/DVD or USB storage device, and build a study list to display to the user.  When the user selects a MRI study to load, ExactVu reads MR images and Presentation States.

3.2 AE Specifications

Application Profile Identifier Role Real World Activity Service Class

CT/MR Studies on CD-R

STD-CTMR-CD

FSR

Read Images and Presentations

Interchange

CT/MR Studies on CD-R

STD-CTMR-DVD

FSR

Read Images and Presentations

Interchange

General Purpose CD-R Interchange

STD-GEN-CD

FSR

Read Images and Presentations

Interchange

General Purpose USB Interchange

STD-GEN-USB

FSR

Read Images and Presentations

Interchange

4 Support of Character Sets

 The following table lists the character sets used in ExactVu.

Character Set Description Defined Term ISO Registration Number Code Element Character Set AE Role

Latin alphabet No. 2

ISO 2022 IR 101

ISO_IR 101

G2

Supplementary set of ISO 8859

Storage SCU, FSR

Default repertoire

ISO 2022 IR 6

ISO_IR 6

G0

ISO 646

FSR

5 Security

ExactVu does not support any specific security measures. It is assumed that ExactVu is used within a secured environment. It is assumed that a secured environment includes at a minimum:

  • Firewall or router protections to ensure that only approved external hosts have network access to ExactVu
  • Firewall or router protections to ensure that ExactVu only has network access to approved external hosts and services
  • Any communication with external hosts and services outside the locally secured environment use appropriate secure network channels (e.g. such as a Virtual Private Network (VPN))
  • Other network security procedures such as automated intrusion detection may be appropriate in some environments
  • Additional security features may be established by the local security policy and are beyond the scope of this DICOM Conformance Statement

Apendix A - Private Attributes

Data Dictionary of Private Attribute

ExactVu adds EVuPrivateInfo and EvuPrivateBinary private module to indicate private information and data.

Private Group “EvuPrivateInfo”

Attribute Name Tag VR VM Use

Private Creator ID

7171, 0010

LO

1

“EVuPrivateInfo”. Reserve element numbers 1000-10FF of group 7171 in the SOP instance

 

7171,102B

LT

2

Private referenced proprietary image (SOP class and instance UID)

Private Group “EvuPrivateBinary”

Attribute Name

Tag

VR

VM

Use

Private Creator ID

9191, 0010

LO

1

“EVuPrivateInBinary”. Reserve element numbers 1000-10FF of group 9191 in the SOP instance

 

9191,10E1

OW

1

Private raw data for ExactVu proprietary data


Rev. 1.5



© 2018 Exact imaging
ExactVu™, Exact Imaging™, PRI-MUS™, FusionVu™, Cognitive Assist™ and ExactVu Micro Doppler™ are trademarks of Exact Imaging.
ExactVu™ micro-ultrasound system is available for sale in the European Union (CE Mark), the United States (FDA 510(k) clearance), and in Canada (Health Canada license).