/*
  Imaging appropriateness — order-select rule for early lumbar MRI in low back pain.

  Fires when a draft lumbar spine MRI order (CDS Hooks context.draftOrders,
  merged into prefetch by cds-server) is placed for a patient whose low back
  pain started within the last 6 weeks and who has no red-flag condition
  (cauda equina syndrome, malignancy). Guidance follows ACR Appropriateness
  Criteria / Choosing Wisely: conservative therapy first; plain radiographs
  when imaging is clinically required.

  Red-flag and diagnosis sets are hand-curated v0.1 ValueSets; the upgrade
  path (full ACR criteria) stays behind the ValueSet layer.
*/
library AtriusImagingAppropriateness version '0.1.0'

using FHIR version '4.0.1'
using AtriusIn version '0.1.0'

include FHIRHelpers version '4.4.000' called FHIRHelpers
include AtriusCommon version '0.1.0'

valueset "Lumbar Spine MRI": 'https://atrius.in/fhir/r4/atrius-in/ValueSet/atrius-vs-lumbar-spine-mri'
valueset "Low Back Pain": 'https://atrius.in/fhir/r4/atrius-in/ValueSet/atrius-vs-low-back-pain'
valueset "Lumbar Imaging Red Flags": 'https://atrius.in/fhir/r4/atrius-in/ValueSet/atrius-vs-lumbar-imaging-red-flags'

context Patient

define "Draft Lumbar MRI Orders":
  [ServiceRequest: "Lumbar Spine MRI"] R
    where R.status = 'draft'

define "Low Back Pain Conditions":
  ([ConditionEncounterDiagnosis: "Low Back Pain"] union [ConditionProblemsHealthConcerns: "Low Back Pain"]) C
    where C.isActive()

define "Acute Low Back Pain":
  exists (
    "Low Back Pain Conditions" C
      where start of C.onset.toConditionTimingInterval() after (Now() - 6 weeks)
  )

define "Red Flag Conditions":
  ([ConditionEncounterDiagnosis: "Lumbar Imaging Red Flags"] union [ConditionProblemsHealthConcerns: "Lumbar Imaging Red Flags"]) C
    where C.isActive()

define "Has Red Flags":
  exists "Red Flag Conditions"

define "Early Lumbar MRI Without Red Flags":
  exists "Draft Lumbar MRI Orders"
    and "Acute Low Back Pain"
    and not "Has Red Flags"

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