Supplement 155Imaging Reports using HL7 CDA

Status Report to WG-062014/04/01

Harry Solomon

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Goals

• Foundational architecture for an evolving family of imaging reports

• Initial templates for radiology reports, aligned with RSNA RadLex and Reporting Initiative

• Primarily narrative, with some discrete data; evolving to more discrete data over time

• Diagnostic and screening; evolving to interventional, cardiac, anatomic path, etc.

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HL7 Clinical Document Architecture

• The scope of the CDA is the standardization of clinical documents for exchange.

• A clinical document is a record of observations and other services with the following characteristics:

– Persistence– Stewardship– Potential for authentication– Wholeness– Human readability

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Key Aspects of the CDA

CDA documents are encoded in Extensible Markup Language (XML)CDA documents derive their meaning from the HL7 v3 Reference Information Model (RIM ) and use HL7 v3 Data TypesA CDA document consists of a header and a body• Header is consistent across all clinical documents -

identifies and classifies the document, provides information on patient, provider, encounter, and authentication; allows document management, compilation of an individual patient's clinical documents into an electronic patient record

• Body contains narrative text / multimedia content (level 1), optionally structured into sections with coded titles and tagged narrative content (level 2), optionally augmented by coded equivalents to narrative (level 3)

CDA documents for a particular use may be constrained by a Template

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Core concepts of RIM

Every happening is an Act• Procedure, observation, medication, supply, registration,

etc.Acts are related through an ActRelationship• composition, preconditions, revisions, support, etc.Participation defines involvement in an Act• author, performer, subject, location, etc.The participants are Roles• patient, agent, responsible party.Roles are played and scoped by Entities• persons, organizations, material, places, devices, etc.

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… an administrationof albuterol…

RIM Classes and Color Coding

Act0..*1 0..*

1Entity ParticipationRole0..1

0..*

0..1

0..*

Plays

Scopes

A person …Mr Joe Public …

… playing the rolepatient …

… participates asthe subject of …

… an observationAsthma …

ActRelation-

ship0..1

0..*

1

1

Source

Target

… which is theReason for …

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CDA Release 2 Information Model

Header Body

ParticipantsSections/Headings

Clinical Statements/Coded Entries

ExtlRefsContext

Doc ID&Type

StartHere

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CDA Structured Body

Structured Body

SectionText

SectionText

SectionText

SectionText

SectionText

SectionText

EntryCoded statement

EntryCoded statement

EntryCoded statement

Arrows are Act Relationships • Has component, Derived from, etc.Entries are coded clinical statements• Observation, Procedure, Substance administration, etc.

EntryCoded statement

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Sample CDA

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Narrative and Coded Info

CDA structured body requires human-readable “Narrative Block”, all that is needed to reproduce the legally attested clinical contentCDA allows optional machine-readable coded “Entries”, which drive automated processesNarrative may be flagged as derived from Entries • Textual rendering of coded entries’ content, and contains no

clinical content not derived from the entries General method for coding clinical statements is a hard, unsolved problem• CDA allows incremental improvement to amount of coded

data without breaking the model

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Narrative and Coded Entry Example

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Purposes of templates

• Reduce variability, improve interoperability • Normalize best practice• Support automation of report production• Support validation of report content

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Multiple layers of constraint

HL7 v3 RIMAbstract Data Classes

CDA r2Refined Data Classes and

structures for clinical documents

DICOM (Sup 155)Additional requirements and

templates for radiology reports

Professional ContentSpecific content for

specialized procedures

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Sup 155 as greenCDA

• greenCDA is the concept that CDA implementation can be simplified by abstractions bridging between use cases and CDA formal syntax requirements

• Defines data elements, using “business names”, that can be invoked by professional content specifications, without knowledge of CDA structures

• E.g., professional content can specify “impression:text”, or “contrast:name” and “contrast:volume”, and Sup 155 specifies how/where those are instantiated in a CDA structure

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Clinical Knowledge

Report Authoring Template

Report Authoring Process

Imaging Study Data

Clinician Interpretation

CDA Report Instance

Templates

Element Public

Interface

Element CDA

Structure

Report Formatting

Process

CDA Imaging Report

Document

Authoring Template Element Structure

IHE MRRT

RSNA RadReport

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Sup 155 editorial style

• Following conventions of HL7 CDA implementation guides, including Consolidated CDA, and emerging HL7 Templates Standard (in ballot reconciliation)

• Library of document, section, and entry templates • Templates specified as table aligned to XML, plus

supplemental narrative conformance statements (conceptually similar to Part 3 module style)

• XML examples provided• Not being generated from tooling (MDHT or Trifolia)

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Radiology Report Document TemplateName XPath Card. Verb Data

TypeValue

Radiology Report

ClinicalDocument

  templateId 1..1 SHALL SET<II>    @root 1..1 SHALL    1.2.840.10008.20.1.1Doc type code

code 1..1 SHALL CD  

General header

  1..1 SHALL   General Header

Imaging header

  1..1 SHALL   Imaging Header

  component 1..1 SHALL      structuredBody 1..1 SHALL    Current Procedure

component 1..1 SHALL   Current Imaging Procedure Description

Clinical Information

component 0..1 MAY   Clinical Information

Comparison Study 

component 0..1 MAY   Comparison / Previous Findings

Findings component 0..1 MAY   Findings Impressions  component 1..1 SHALL   ImpressionsAddendum  component 0..* MAY   Addendum

component 0..1 SHOULD   DICOM Object Catalog4/1/2014

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Name XPath Card. Verb Data Type

Value

Comparison Study

section

 @classCode

1..1 SHALL   2.16.840.1.113883.5.6 (HL7ActClass) = DOCSECT

 @moodCode

1..1 SHALL   2.16.840.1.113883.5.1001 (ActMood) = EVN

 templateId

1..1 SHALL SET<II>  

 @root

1..1 SHALL   tbd

  id 1..* SHALL II    code 1..1 SHALL CD 18834-2, LOINC, “Radiology Comparison

study”

text text 0..1 SHOULD ED  author

author0..1 MAY   Observer Context

procedure entry 0..1 MAY   Imaging Procedure

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Name XPath Card. Verb Data Type

Value

Author AssignedAuthor  @classCode 1..1 SHALL   2.16.840.1.113883.5.110

(RoleClass) = ASSIGNED  templateId 1..1 SHALL SET<II>    @root 1..1 SHALL   2.16.840.1.113883.10.20.6.2.4  id 1..1 SHALL      person 0..1 SHOULD    Name name 1..1 SHALL PN    authoringDevice 0..1 SHOULD    Device softwareName 1..1 SHALL ST  

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Subsections

• Some defined in templates for specific uses– Contrast, Radiation Dose, Fetus Finding

• Requirements for user-labeled subsections – Content for an arbitrary topic (a particular organ

or anatomic feature, a lesion, a tumor, etc.)– Required section.title with topic name– No section.code, hence no semantic post-

coordination to section entries

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Why no section.code in user-labeled subsection?

• section.code uses LOINC codes with scale=NAR– i.e., its value in section.text is a narrative block– A concept that scopes a value (observable entity)

• The concepts used as user-labels (typically anatomy) are the wrong “part of speech”– Do not have formal semantics of scoping a value– Need something like a post-coordinated phrase:

FindingsSection+FindingSite=<anatomy> (cf. DICOM)– CDA does not have section targetSiteCode or Participation

for anatomic site

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Body and Narrative Sections

External Relations

• HL7• RSNA

– Radiology Reporting– RadLex

• IHE– MRRT

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Relationship to HL7

• Builds on HL7 Diagnostic Imaging Report (DIR) CDA IG informative standard

• Leverages harmonization done for Consolidated CDA IG r2 (C-CDA)

• Public comment to be solicited in HL7 ballot cycle parallel to DICOM PC and LB periods

• May be balloted as HL7 standard (DIR r2), recognizing updates will be handled in DICOM continuous maintenance process

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Reuse of C-CDA Templates

• Intent is to be harmonized with C-CDA• But C-CDA is US Realm only – DICOM needs to

be Universal Realm• Challenges to re-use based on shortcuts taken

– Vocabulary bindings hard coded into templates– Vocabulary bindings US Realm only

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RSNA Reporting Initiative

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radreport.org

CT Brain (example)Clinical History * Medical history * Risk factors * Allergies, if relevant * Reason for exam, including medical necessity: [headache | stroke | dizziness | trauma]Imaging Technique * Time of image acquisition * Imaging device [MR, CT] * Image acquisition parameters, such as device settings, patient positioning, interventions (e.g., Valsalva) * Contrast materials and other medications administered (including name, dose, route, and time) * Radiation doseComparison * Date and type of previous exams reviewed, if applicableObservations * Extra axial spaces: [normal in size and morphology for the patient's age* | widened] * Hemorrhage: [none* ; subdural ; subarachnoid; epidural, intraventricular, parenchymal] * Ventricular system: [normal in size and morphology for the patient's age* | enlarged | small] * Basal cisterns: [normal* | enlarged | small] * Cerebral parenchyma: [normal*; microvascular changes; infarction; encephalomalacia; gliosis; hemorrhage] * Midline shift: [none* | leftward shift | rightward shift] …Impressions

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RadLex tagged content

• RadLex is an RSNA lexicon designed to tag concepts for subsequent indexing/retrieval

• Atomic concepts only – no compositional grammar • Use CDA <linkHtml> non-attested link in narrative

block

<section> ... <text> ...<content>There is focal opacity at the right lung base most likely representing right lower lobe atelectasis.<linkHtml href=http://www.radlex.org/RID/RID1302 /><linkHtml href=http://www.radlex.org/RID/RID28493 /> </content></text> ... </section>

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Relationship to IHE MRRT

• Management of Radiology Report Templates is an IHE Profile that (inter alia) defines an HTML scheme for encoding report production templates

• Revisions needed for MRRT to use DICOM defined business names, supporting encoding of reports as CDA using Sup 155

• Informative annex in DICOM about use of templates in report production, including MRRT

• Should we invite IHE Radiology to submit revised HTML scheme for standardization in Sup 155?

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DICOM Stuff

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What about Part 20?

• Designed for mapping SR to CDA• Includes CDA structures also used in Sup 155

templates (e.g., DICOM Object Catalog, header structures, image references, etc.)

• Suggest general reworking combining current Part 20 with new material in Sup 155, to produce a replacement Part 20

• How to handle new version of current Part 20 material?

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Conformance

• What needs to specified in Part 2 with respect to conformance?

• Creator claim of document level templates– That would just be one, for now– How about specific uses and/or RSNA templates?

• No expected receiver claims beyond general HL7 CDA receiver conformance– Not intended to be in the DICOM conformance

world

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Schedule• April 1: WG-06 – review overall

strategy • May-Jun: WG-06 webinars for line

by line review• Jun 23-27: WG-06 –Release for PC• Mid July-mid Sept: Public Comment• Sept 8-12: WG-06 – review

comments and necessary revisions• Nov 10-14: WG-06 – Release for LB• Nov-Jan: Letter Ballot• Jan 12-16: WG-06 – Final Text Draft

• ?? Publish FT

• May 5-9: HL7 – review with Structured Documents WG, and “clean draft” Supplement

• Aug 8-Sep 8: HL7 Comment Only ballot

• Sep 15-19: HL7 – review comments

• Dec 12-Jan 12:HL7 Comment Only ballot

• Jan 19-23: HL7 – review comments and Final Text Draft

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Should Sup155 be DSTU?

• DICOM generally has not found DSTU to be useful

• HL7 uses it regularly, especially for CDA IG’s

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