HL7 Europe Imaging Study Report, published by HL7 Europe. This guide is not an authorized publication; it is the continuous build for version 0.1.0-build built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/oijauregui/ehdsimaging/ and changes regularly. See the Directory of published versions
| Official URL: https://www.xt-ehr.eu/specifications/fhir/StructureDefinition/EHDSImagingStudy | Version: 0.1.0 | |||
| Draft as of 2025-03-21 | Computable Name: EHDSImagingStudy | |||
| Copyright/Legal: Used by permission of HL7 Europe, all rights reserved Creative Commons License | ||||
C.32 - EHDS refined base model for Imaging study
Usages:
You can also check for usages in the FHIR IG Statistics
Description of Profiles, Differentials, Snapshots and how the different presentations work.
| Name | Flags | Card. | Type | Description & Constraints    Filter:   | 
|---|---|---|---|---|
|   EHDSImagingStudy | 0..* | Base | Imaging study model Instances of this logical model can be the target of a Reference | |
|    identifier | 1..* | Identifier | C.32.1 - Identifier | |
|    modality | 0..* | CodeableConcept | C.32.2 - Modality Binding Description: (preferred): DICOM CID029 | |
|    subject | 1..1 | Reference(Patient model | Device model) | C.32.3 - Subject | |
|    encounter | 0..1 | Reference(Encounter model) | C.32.4 - Encounter | |
|    started | 0..1 | dateTime | C.32.5 - Started | |
|    basedOn | 0..* | Reference(Service request model) | C.32.6 - Based on | |
|    numberOfSeries | 0..1 | unsignedInt | C.32.7 - Number of series | |
|    numberOfInstances | 0..1 | unsignedInt | C.32.8 - Number of instances | |
|    description | 0..1 | string | C.32.9 - Description | |
|    studyCustodian | 0..1 | EHDSOrganization | C.32.10 - Study custodian | |
|    studyEndpoint | 0..1 | EHDSEndpoint | C.32.11 - Study endpoint | |
|    series | 0..* | Base | C.32.12 - Series | |
|     seriesUid | 1..1 | id | C.32.12.1 - Series UID | |
|     number | 0..1 | unsignedInt | C.32.12.2 - Number | |
|     acquisitionModality | 1..1 | CodeableConcept | C.32.12.3 - Acquisition modality Binding Description: (preferred): DICOM CID029 | |
|     description | 0..1 | string | C.32.12.4 - Description | |
|     numberOfInstances | 0..1 | unsignedInt | C.32.12.5 - Number of instances | |
|     seriesEndpoint | 0..1 | EHDSEndpoint | C.32.12.6 - Series endpoint | |
|     bodySite | 0..1 | CodeableConcept | C.32.12.7 - Body site Binding Description: (preferred): SNOMED CT | |
|     laterality | 0..1 | CodeableConcept | C.32.12.8 - Laterality Binding Description: (preferred): SNOMED CT | |
|     specimen | 0..* | Reference(Specimen model) | C.32.12.9 - Specimen | |
|     started | 0..1 | dateTime | C.32.12.10 - Started | |
|     instancesInTheSeries | 0..* | Base | C.32.12.11 - Instances in the series | |
|      instanceTitle | 0..1 | string | C.32.12.11.1 - Instance title | |
|      instanceUid | 1..1 | id | C.32.12.11.2 - Instance UID | |
|      sopClass | 1..1 | uri | C.32.12.11.3 - SOP class | |
|      instanceNumber | 0..1 | unsignedInt | C.32.12.11.4 - Instance number | |
|      radiationDoseInformation | 0..1 | Base | C.32.12.11.5 - Radiation dose information | |
|       kap | 0..1 | Quantity | C.32.12.11.5.1 - KAP | |
|       totalKerma | 0..1 | Quantity | C.32.12.11.5.2 - Total Kerma | |
|       endTubeKerma | 0..1 | Quantity | C.32.12.11.5.3 - End tube Kerma | |
|       breastThickness | 0..1 | Quantity | C.32.12.11.5.4 - Breast thickness | |
|       abd | 0..1 | Quantity | C.32.12.11.5.5 - 2ABD | |
|    phase | 0..1 | Base | C.32.13 - Phase | |
|     phaseCode | 1..1 | CodeableConcept | C.32.13.1 - Phase code Binding Description: (preferred): SNOMED CT | |
|     radiationDose | 0..1 | Quantity | C.32.13.2 - Radiation dose | |
|  Documentation for this format | ||||
| Path | Conformance | ValueSet | URI | 
| EHDSImagingStudy.modality | preferred | ||
| EHDSImagingStudy.series.acquisitionModality | preferred | ||
| EHDSImagingStudy.series.bodySite | preferred | ||
| EHDSImagingStudy.series.laterality | preferred | ||
| EHDSImagingStudy.phase.phaseCode | preferred | 
This structure is derived from Base
| Name | Flags | Card. | Type | Description & Constraints    Filter:   | 
|---|---|---|---|---|
|   EHDSImagingStudy | 0..* | Base | Imaging study model Instances of this logical model can be the target of a Reference | |
|    identifier | 1..* | Identifier | C.32.1 - Identifier | |
|    modality | 0..* | CodeableConcept | C.32.2 - Modality Binding Description: (preferred): DICOM CID029 | |
|    subject | 1..1 | Reference(Patient model | Device model) | C.32.3 - Subject | |
|    encounter | 0..1 | Reference(Encounter model) | C.32.4 - Encounter | |
|    started | 0..1 | dateTime | C.32.5 - Started | |
|    basedOn | 0..* | Reference(Service request model) | C.32.6 - Based on | |
|    numberOfSeries | 0..1 | unsignedInt | C.32.7 - Number of series | |
|    numberOfInstances | 0..1 | unsignedInt | C.32.8 - Number of instances | |
|    description | 0..1 | string | C.32.9 - Description | |
|    studyCustodian | 0..1 | EHDSOrganization | C.32.10 - Study custodian | |
|    studyEndpoint | 0..1 | EHDSEndpoint | C.32.11 - Study endpoint | |
|    series | 0..* | Base | C.32.12 - Series | |
|     seriesUid | 1..1 | id | C.32.12.1 - Series UID | |
|     number | 0..1 | unsignedInt | C.32.12.2 - Number | |
|     acquisitionModality | 1..1 | CodeableConcept | C.32.12.3 - Acquisition modality Binding Description: (preferred): DICOM CID029 | |
|     description | 0..1 | string | C.32.12.4 - Description | |
|     numberOfInstances | 0..1 | unsignedInt | C.32.12.5 - Number of instances | |
|     seriesEndpoint | 0..1 | EHDSEndpoint | C.32.12.6 - Series endpoint | |
|     bodySite | 0..1 | CodeableConcept | C.32.12.7 - Body site Binding Description: (preferred): SNOMED CT | |
|     laterality | 0..1 | CodeableConcept | C.32.12.8 - Laterality Binding Description: (preferred): SNOMED CT | |
|     specimen | 0..* | Reference(Specimen model) | C.32.12.9 - Specimen | |
|     started | 0..1 | dateTime | C.32.12.10 - Started | |
|     instancesInTheSeries | 0..* | Base | C.32.12.11 - Instances in the series | |
|      instanceTitle | 0..1 | string | C.32.12.11.1 - Instance title | |
|      instanceUid | 1..1 | id | C.32.12.11.2 - Instance UID | |
|      sopClass | 1..1 | uri | C.32.12.11.3 - SOP class | |
|      instanceNumber | 0..1 | unsignedInt | C.32.12.11.4 - Instance number | |
|      radiationDoseInformation | 0..1 | Base | C.32.12.11.5 - Radiation dose information | |
|       kap | 0..1 | Quantity | C.32.12.11.5.1 - KAP | |
|       totalKerma | 0..1 | Quantity | C.32.12.11.5.2 - Total Kerma | |
|       endTubeKerma | 0..1 | Quantity | C.32.12.11.5.3 - End tube Kerma | |
|       breastThickness | 0..1 | Quantity | C.32.12.11.5.4 - Breast thickness | |
|       abd | 0..1 | Quantity | C.32.12.11.5.5 - 2ABD | |
|    phase | 0..1 | Base | C.32.13 - Phase | |
|     phaseCode | 1..1 | CodeableConcept | C.32.13.1 - Phase code Binding Description: (preferred): SNOMED CT | |
|     radiationDose | 0..1 | Quantity | C.32.13.2 - Radiation dose | |
|  Documentation for this format | ||||
| Path | Conformance | ValueSet | URI | 
| EHDSImagingStudy.modality | preferred | ||
| EHDSImagingStudy.series.acquisitionModality | preferred | ||
| EHDSImagingStudy.series.bodySite | preferred | ||
| EHDSImagingStudy.series.laterality | preferred | ||
| EHDSImagingStudy.phase.phaseCode | preferred | 
| Name | Flags | Card. | Type | Description & Constraints    Filter:   | 
|---|---|---|---|---|
|   EHDSImagingStudy | 0..* | Base | Imaging study model Instances of this logical model can be the target of a Reference | |
|    identifier | 1..* | Identifier | C.32.1 - Identifier | |
|    modality | 0..* | CodeableConcept | C.32.2 - Modality Binding Description: (preferred): DICOM CID029 | |
|    subject | 1..1 | Reference(Patient model | Device model) | C.32.3 - Subject | |
|    encounter | 0..1 | Reference(Encounter model) | C.32.4 - Encounter | |
|    started | 0..1 | dateTime | C.32.5 - Started | |
|    basedOn | 0..* | Reference(Service request model) | C.32.6 - Based on | |
|    numberOfSeries | 0..1 | unsignedInt | C.32.7 - Number of series | |
|    numberOfInstances | 0..1 | unsignedInt | C.32.8 - Number of instances | |
|    description | 0..1 | string | C.32.9 - Description | |
|    studyCustodian | 0..1 | EHDSOrganization | C.32.10 - Study custodian | |
|    studyEndpoint | 0..1 | EHDSEndpoint | C.32.11 - Study endpoint | |
|    series | 0..* | Base | C.32.12 - Series | |
|     seriesUid | 1..1 | id | C.32.12.1 - Series UID | |
|     number | 0..1 | unsignedInt | C.32.12.2 - Number | |
|     acquisitionModality | 1..1 | CodeableConcept | C.32.12.3 - Acquisition modality Binding Description: (preferred): DICOM CID029 | |
|     description | 0..1 | string | C.32.12.4 - Description | |
|     numberOfInstances | 0..1 | unsignedInt | C.32.12.5 - Number of instances | |
|     seriesEndpoint | 0..1 | EHDSEndpoint | C.32.12.6 - Series endpoint | |
|     bodySite | 0..1 | CodeableConcept | C.32.12.7 - Body site Binding Description: (preferred): SNOMED CT | |
|     laterality | 0..1 | CodeableConcept | C.32.12.8 - Laterality Binding Description: (preferred): SNOMED CT | |
|     specimen | 0..* | Reference(Specimen model) | C.32.12.9 - Specimen | |
|     started | 0..1 | dateTime | C.32.12.10 - Started | |
|     instancesInTheSeries | 0..* | Base | C.32.12.11 - Instances in the series | |
|      instanceTitle | 0..1 | string | C.32.12.11.1 - Instance title | |
|      instanceUid | 1..1 | id | C.32.12.11.2 - Instance UID | |
|      sopClass | 1..1 | uri | C.32.12.11.3 - SOP class | |
|      instanceNumber | 0..1 | unsignedInt | C.32.12.11.4 - Instance number | |
|      radiationDoseInformation | 0..1 | Base | C.32.12.11.5 - Radiation dose information | |
|       kap | 0..1 | Quantity | C.32.12.11.5.1 - KAP | |
|       totalKerma | 0..1 | Quantity | C.32.12.11.5.2 - Total Kerma | |
|       endTubeKerma | 0..1 | Quantity | C.32.12.11.5.3 - End tube Kerma | |
|       breastThickness | 0..1 | Quantity | C.32.12.11.5.4 - Breast thickness | |
|       abd | 0..1 | Quantity | C.32.12.11.5.5 - 2ABD | |
|    phase | 0..1 | Base | C.32.13 - Phase | |
|     phaseCode | 1..1 | CodeableConcept | C.32.13.1 - Phase code Binding Description: (preferred): SNOMED CT | |
|     radiationDose | 0..1 | Quantity | C.32.13.2 - Radiation dose | |
|  Documentation for this format | ||||
| Path | Conformance | ValueSet | URI | 
| EHDSImagingStudy.modality | preferred | ||
| EHDSImagingStudy.series.acquisitionModality | preferred | ||
| EHDSImagingStudy.series.bodySite | preferred | ||
| EHDSImagingStudy.series.laterality | preferred | ||
| EHDSImagingStudy.phase.phaseCode | preferred | 
This structure is derived from Base
Summary
Mandatory: 0 element(7 nested mandatory elements)
Structures
This structure refers to these other structures:
Key Elements View
| Name | Flags | Card. | Type | Description & Constraints    Filter:   | 
|---|---|---|---|---|
|   EHDSImagingStudy | 0..* | Base | Imaging study model Instances of this logical model can be the target of a Reference | |
|    identifier | 1..* | Identifier | C.32.1 - Identifier | |
|    modality | 0..* | CodeableConcept | C.32.2 - Modality Binding Description: (preferred): DICOM CID029 | |
|    subject | 1..1 | Reference(Patient model | Device model) | C.32.3 - Subject | |
|    encounter | 0..1 | Reference(Encounter model) | C.32.4 - Encounter | |
|    started | 0..1 | dateTime | C.32.5 - Started | |
|    basedOn | 0..* | Reference(Service request model) | C.32.6 - Based on | |
|    numberOfSeries | 0..1 | unsignedInt | C.32.7 - Number of series | |
|    numberOfInstances | 0..1 | unsignedInt | C.32.8 - Number of instances | |
|    description | 0..1 | string | C.32.9 - Description | |
|    studyCustodian | 0..1 | EHDSOrganization | C.32.10 - Study custodian | |
|    studyEndpoint | 0..1 | EHDSEndpoint | C.32.11 - Study endpoint | |
|    series | 0..* | Base | C.32.12 - Series | |
|     seriesUid | 1..1 | id | C.32.12.1 - Series UID | |
|     number | 0..1 | unsignedInt | C.32.12.2 - Number | |
|     acquisitionModality | 1..1 | CodeableConcept | C.32.12.3 - Acquisition modality Binding Description: (preferred): DICOM CID029 | |
|     description | 0..1 | string | C.32.12.4 - Description | |
|     numberOfInstances | 0..1 | unsignedInt | C.32.12.5 - Number of instances | |
|     seriesEndpoint | 0..1 | EHDSEndpoint | C.32.12.6 - Series endpoint | |
|     bodySite | 0..1 | CodeableConcept | C.32.12.7 - Body site Binding Description: (preferred): SNOMED CT | |
|     laterality | 0..1 | CodeableConcept | C.32.12.8 - Laterality Binding Description: (preferred): SNOMED CT | |
|     specimen | 0..* | Reference(Specimen model) | C.32.12.9 - Specimen | |
|     started | 0..1 | dateTime | C.32.12.10 - Started | |
|     instancesInTheSeries | 0..* | Base | C.32.12.11 - Instances in the series | |
|      instanceTitle | 0..1 | string | C.32.12.11.1 - Instance title | |
|      instanceUid | 1..1 | id | C.32.12.11.2 - Instance UID | |
|      sopClass | 1..1 | uri | C.32.12.11.3 - SOP class | |
|      instanceNumber | 0..1 | unsignedInt | C.32.12.11.4 - Instance number | |
|      radiationDoseInformation | 0..1 | Base | C.32.12.11.5 - Radiation dose information | |
|       kap | 0..1 | Quantity | C.32.12.11.5.1 - KAP | |
|       totalKerma | 0..1 | Quantity | C.32.12.11.5.2 - Total Kerma | |
|       endTubeKerma | 0..1 | Quantity | C.32.12.11.5.3 - End tube Kerma | |
|       breastThickness | 0..1 | Quantity | C.32.12.11.5.4 - Breast thickness | |
|       abd | 0..1 | Quantity | C.32.12.11.5.5 - 2ABD | |
|    phase | 0..1 | Base | C.32.13 - Phase | |
|     phaseCode | 1..1 | CodeableConcept | C.32.13.1 - Phase code Binding Description: (preferred): SNOMED CT | |
|     radiationDose | 0..1 | Quantity | C.32.13.2 - Radiation dose | |
|  Documentation for this format | ||||
| Path | Conformance | ValueSet | URI | 
| EHDSImagingStudy.modality | preferred | ||
| EHDSImagingStudy.series.acquisitionModality | preferred | ||
| EHDSImagingStudy.series.bodySite | preferred | ||
| EHDSImagingStudy.series.laterality | preferred | ||
| EHDSImagingStudy.phase.phaseCode | preferred | 
Differential View
This structure is derived from Base
| Name | Flags | Card. | Type | Description & Constraints    Filter:   | 
|---|---|---|---|---|
|   EHDSImagingStudy | 0..* | Base | Imaging study model Instances of this logical model can be the target of a Reference | |
|    identifier | 1..* | Identifier | C.32.1 - Identifier | |
|    modality | 0..* | CodeableConcept | C.32.2 - Modality Binding Description: (preferred): DICOM CID029 | |
|    subject | 1..1 | Reference(Patient model | Device model) | C.32.3 - Subject | |
|    encounter | 0..1 | Reference(Encounter model) | C.32.4 - Encounter | |
|    started | 0..1 | dateTime | C.32.5 - Started | |
|    basedOn | 0..* | Reference(Service request model) | C.32.6 - Based on | |
|    numberOfSeries | 0..1 | unsignedInt | C.32.7 - Number of series | |
|    numberOfInstances | 0..1 | unsignedInt | C.32.8 - Number of instances | |
|    description | 0..1 | string | C.32.9 - Description | |
|    studyCustodian | 0..1 | EHDSOrganization | C.32.10 - Study custodian | |
|    studyEndpoint | 0..1 | EHDSEndpoint | C.32.11 - Study endpoint | |
|    series | 0..* | Base | C.32.12 - Series | |
|     seriesUid | 1..1 | id | C.32.12.1 - Series UID | |
|     number | 0..1 | unsignedInt | C.32.12.2 - Number | |
|     acquisitionModality | 1..1 | CodeableConcept | C.32.12.3 - Acquisition modality Binding Description: (preferred): DICOM CID029 | |
|     description | 0..1 | string | C.32.12.4 - Description | |
|     numberOfInstances | 0..1 | unsignedInt | C.32.12.5 - Number of instances | |
|     seriesEndpoint | 0..1 | EHDSEndpoint | C.32.12.6 - Series endpoint | |
|     bodySite | 0..1 | CodeableConcept | C.32.12.7 - Body site Binding Description: (preferred): SNOMED CT | |
|     laterality | 0..1 | CodeableConcept | C.32.12.8 - Laterality Binding Description: (preferred): SNOMED CT | |
|     specimen | 0..* | Reference(Specimen model) | C.32.12.9 - Specimen | |
|     started | 0..1 | dateTime | C.32.12.10 - Started | |
|     instancesInTheSeries | 0..* | Base | C.32.12.11 - Instances in the series | |
|      instanceTitle | 0..1 | string | C.32.12.11.1 - Instance title | |
|      instanceUid | 1..1 | id | C.32.12.11.2 - Instance UID | |
|      sopClass | 1..1 | uri | C.32.12.11.3 - SOP class | |
|      instanceNumber | 0..1 | unsignedInt | C.32.12.11.4 - Instance number | |
|      radiationDoseInformation | 0..1 | Base | C.32.12.11.5 - Radiation dose information | |
|       kap | 0..1 | Quantity | C.32.12.11.5.1 - KAP | |
|       totalKerma | 0..1 | Quantity | C.32.12.11.5.2 - Total Kerma | |
|       endTubeKerma | 0..1 | Quantity | C.32.12.11.5.3 - End tube Kerma | |
|       breastThickness | 0..1 | Quantity | C.32.12.11.5.4 - Breast thickness | |
|       abd | 0..1 | Quantity | C.32.12.11.5.5 - 2ABD | |
|    phase | 0..1 | Base | C.32.13 - Phase | |
|     phaseCode | 1..1 | CodeableConcept | C.32.13.1 - Phase code Binding Description: (preferred): SNOMED CT | |
|     radiationDose | 0..1 | Quantity | C.32.13.2 - Radiation dose | |
|  Documentation for this format | ||||
| Path | Conformance | ValueSet | URI | 
| EHDSImagingStudy.modality | preferred | ||
| EHDSImagingStudy.series.acquisitionModality | preferred | ||
| EHDSImagingStudy.series.bodySite | preferred | ||
| EHDSImagingStudy.series.laterality | preferred | ||
| EHDSImagingStudy.phase.phaseCode | preferred | 
Snapshot View
| Name | Flags | Card. | Type | Description & Constraints    Filter:   | 
|---|---|---|---|---|
|   EHDSImagingStudy | 0..* | Base | Imaging study model Instances of this logical model can be the target of a Reference | |
|    identifier | 1..* | Identifier | C.32.1 - Identifier | |
|    modality | 0..* | CodeableConcept | C.32.2 - Modality Binding Description: (preferred): DICOM CID029 | |
|    subject | 1..1 | Reference(Patient model | Device model) | C.32.3 - Subject | |
|    encounter | 0..1 | Reference(Encounter model) | C.32.4 - Encounter | |
|    started | 0..1 | dateTime | C.32.5 - Started | |
|    basedOn | 0..* | Reference(Service request model) | C.32.6 - Based on | |
|    numberOfSeries | 0..1 | unsignedInt | C.32.7 - Number of series | |
|    numberOfInstances | 0..1 | unsignedInt | C.32.8 - Number of instances | |
|    description | 0..1 | string | C.32.9 - Description | |
|    studyCustodian | 0..1 | EHDSOrganization | C.32.10 - Study custodian | |
|    studyEndpoint | 0..1 | EHDSEndpoint | C.32.11 - Study endpoint | |
|    series | 0..* | Base | C.32.12 - Series | |
|     seriesUid | 1..1 | id | C.32.12.1 - Series UID | |
|     number | 0..1 | unsignedInt | C.32.12.2 - Number | |
|     acquisitionModality | 1..1 | CodeableConcept | C.32.12.3 - Acquisition modality Binding Description: (preferred): DICOM CID029 | |
|     description | 0..1 | string | C.32.12.4 - Description | |
|     numberOfInstances | 0..1 | unsignedInt | C.32.12.5 - Number of instances | |
|     seriesEndpoint | 0..1 | EHDSEndpoint | C.32.12.6 - Series endpoint | |
|     bodySite | 0..1 | CodeableConcept | C.32.12.7 - Body site Binding Description: (preferred): SNOMED CT | |
|     laterality | 0..1 | CodeableConcept | C.32.12.8 - Laterality Binding Description: (preferred): SNOMED CT | |
|     specimen | 0..* | Reference(Specimen model) | C.32.12.9 - Specimen | |
|     started | 0..1 | dateTime | C.32.12.10 - Started | |
|     instancesInTheSeries | 0..* | Base | C.32.12.11 - Instances in the series | |
|      instanceTitle | 0..1 | string | C.32.12.11.1 - Instance title | |
|      instanceUid | 1..1 | id | C.32.12.11.2 - Instance UID | |
|      sopClass | 1..1 | uri | C.32.12.11.3 - SOP class | |
|      instanceNumber | 0..1 | unsignedInt | C.32.12.11.4 - Instance number | |
|      radiationDoseInformation | 0..1 | Base | C.32.12.11.5 - Radiation dose information | |
|       kap | 0..1 | Quantity | C.32.12.11.5.1 - KAP | |
|       totalKerma | 0..1 | Quantity | C.32.12.11.5.2 - Total Kerma | |
|       endTubeKerma | 0..1 | Quantity | C.32.12.11.5.3 - End tube Kerma | |
|       breastThickness | 0..1 | Quantity | C.32.12.11.5.4 - Breast thickness | |
|       abd | 0..1 | Quantity | C.32.12.11.5.5 - 2ABD | |
|    phase | 0..1 | Base | C.32.13 - Phase | |
|     phaseCode | 1..1 | CodeableConcept | C.32.13.1 - Phase code Binding Description: (preferred): SNOMED CT | |
|     radiationDose | 0..1 | Quantity | C.32.13.2 - Radiation dose | |
|  Documentation for this format | ||||
| Path | Conformance | ValueSet | URI | 
| EHDSImagingStudy.modality | preferred | ||
| EHDSImagingStudy.series.acquisitionModality | preferred | ||
| EHDSImagingStudy.series.bodySite | preferred | ||
| EHDSImagingStudy.series.laterality | preferred | ||
| EHDSImagingStudy.phase.phaseCode | preferred | 
This structure is derived from Base
Summary
Mandatory: 0 element(7 nested mandatory elements)
Structures
This structure refers to these other structures: