Modic vertebral endplate marrow changes

{
  "categories": [
    {
      "outcome_code": "1",
      "conventional_T1": "low_relative_to_normal_vertebral_marrow",
      "conventional_non_fat_suppressed_T2": "high",
      "tissue_correlate": "endplate_disruption_and_fissuring_with_fibrovascular_marrow_replacement_and_increased_water",
      "shorthand": "fibrovascular_or_edematous_pattern"
    },
    {
      "outcome_code": "2",
      "conventional_T1": "high",
      "conventional_non_fat_suppressed_T2": "isointense_to_slightly_high",
      "tissue_correlate": "fatty_yellow_marrow_replacement",
      "shorthand": "fatty_pattern"
    },
    {
      "outcome_code": "3",
      "conventional_T1": "low",
      "conventional_non_fat_suppressed_T2": "low",
      "tissue_correlate": "subchondral_bone_sclerosis",
      "shorthand": "sclerotic_pattern"
    }
  ],
  "applicability": {
    "intended_use": "Describe vertebral endplate-adjacent bone-marrow signal associated with a degenerative disc at each named spinal level.",
    "original_population": "The original classification was developed in lumbar degenerative disc disease; application in the cervical or thoracic spine should retain the region and be labeled as extrapolation rather than silent original validation.",
    "unit_of_analysis": "A disc/endplate level, with the cranial and caudal vertebral endplates, side, anterior-posterior distribution and extent retained rather than a single patient-level type.",
    "required_sequences": [
      "non_fat_suppressed_T1_weighted_MRI",
      "non_fat_suppressed_T2_weighted_MRI_or_sequence_context_that_allows_equivalent_interpretation"
    ],
    "outside_scope": [
      "disc_degeneration_grade_use_Pfirrmann_separately",
      "disc_herniation_or_annular_fissure",
      "canal_or_foraminal_stenosis",
      "proof_of_discitis_osteomyelitis",
      "identification_of_a_pain_generator",
      "treatment_selection"
    ]
  },
  "technical_and_reporting_gate": {
    "reference": "Compare endplate-adjacent signal with normal vertebral marrow on the same examination and interpret it in the patient's age and marrow context.",
    "sequence_dependency": "Field strength, echo time, fat suppression, spatial resolution and other acquisition parameters change conspicuity and apparent extent; record the sequences used when serially measuring or researching Modic change.",
    "fat_suppression_trap": "Fat in type 2 becomes dark on fat-suppressed T2/STIR, so a low signal on those sequences is not sufficient for type 3. Type 3 requires low signal on conventional T1 and non-fat-suppressed T2 plus a sclerotic correlate when available.",
    "CT_radiograph_role": "CT or radiographs may corroborate sclerosis in type 3 but cannot independently assign the MRI signal classification.",
    "comparison_rule": "Serial comparison should use technically comparable sequences; otherwise qualify apparent change in type or extent as technically limited."
  },
  "category_algorithm": [
    {
      "step": 1,
      "pattern": "low_T1_and_high_non_fat_suppressed_T2_adjacent_to_degenerative_endplate",
      "output": "1"
    },
    {
      "step": 2,
      "pattern": "high_T1_and_iso_to_slightly_high_non_fat_suppressed_T2",
      "output": "2"
    },
    {
      "step": 3,
      "pattern": "low_T1_and_low_non_fat_suppressed_T2_with_sclerotic_morphology",
      "output": "3"
    },
    {
      "step": 4,
      "pattern": "more_than_one_pattern_within_the_same_level_or_endplate",
      "output": "mixed_type_with_each_component_retained"
    },
    {
      "step": 5,
      "pattern": "signal_does_not_match_or_required_sequences_are_missing",
      "output": "indeterminate_or_non_Modic_differential"
    }
  ],
  "type_and_mixed_pattern_rules": {
    "type_1": "Low T1/high T2 reflects a water-rich fibrovascular endplate phenotype. The colloquial word active must not be converted into proof of painful inflammation or infection.",
    "type_2": "High T1 with iso/slightly high T2 reflects fatty marrow replacement; use the T1 fat signal and non-fat-suppressed sequence context to avoid misclassification.",
    "type_3": "Low T1/low T2 reflects sclerosis and was detailed in the companion 1988 imaging paper. It is less common and should not be assigned from low STIR signal alone.",
    "mixed_patterns": "Mixed I/II and II/III patterns occur. Report both components and their spatial distribution; do not force the dominant area into a pure type or create an unsupported arithmetic score.",
    "nonordinal_rule": "Types are tissue-signal phenotypes, not three validated steps of symptom severity, treatment urgency or inevitable temporal progression."
  },
  "minimum_structured_report": {
    "anatomy": [
      "disc_level",
      "cranial_endplate",
      "caudal_endplate",
      "laterality_or_centrality",
      "anterior_middle_posterior_distribution"
    ],
    "phenotype": [
      "pure_or_mixed_type",
      "component_types",
      "qualitative_or_contoured_extent",
      "dominant_component_only_if_explicitly_labeled"
    ],
    "companions": [
      "disc_degeneration_and_height",
      "endplate_defect_or_Schmorl_node",
      "erosion_or_destruction",
      "sclerosis",
      "enhancement_if_contrast_given",
      "paraspinal_or_epidural_abnormality",
      "comparison_change"
    ],
    "reproducibility_context": [
      "field_strength",
      "T1_parameters",
      "T2_parameters",
      "fat_suppression",
      "slice_thickness_and_orientation"
    ]
  },
  "type_1_differential_and_safety_gate": {
    "mimics": [
      "infectious_spondylodiscitis",
      "acute_Schmorl_node",
      "acute_or_subacute_fracture",
      "inflammatory_spondyloarthropathy",
      "tumor_or_treatment_related_marrow_change"
    ],
    "infection_supporting_features": [
      "progressive_endplate_erosion_or_destruction",
      "fluid_like_or_markedly_high_disc_T2_signal",
      "disc_and_endplate_enhancement_in_context",
      "paraspinal_or_epidural_phlegmon_or_abscess",
      "systemic_or_laboratory_evidence_of_infection"
    ],
    "enhancement_boundary": "Endplate and disc enhancement can occur with degeneration and infection; enhancement alone does not settle the diagnosis.",
    "diffusion_claw": "On appropriate DWI, a paired well-marginated linear claw at the normal-abnormal marrow interface supports degeneration, while diffuse amorphous DWI signal raises infection concern. This is supportive evidence from a retrospective cohort, not part of the original Modic category or an absolute exclusion test.",
    "action_rule": "If infection, fracture or tumor is plausible, surface that differential and recommend context-appropriate diagnostic escalation independently of the Modic label; never reassure from type 1 alone."
  },
  "symptoms_risk_and_management_context": {
    "pain_association": "A 2018 systematic review of 31 studies found inconsistent associations between Modic change and low-back-pain or activity-limitation outcomes, with substantial heterogeneity and high risk of bias.",
    "pain_generator_rule": "No Modic type proves that the indexed level generates pain, and absence of Modic change does not exclude clinically important discogenic or other spinal pain.",
    "prognosis_rule": "Type and longitudinal conversion do not provide a calibrated individual forecast of pain, disability, degeneration rate, fracture, cancer or surgical outcome.",
    "treatment_rule": "The classification does not choose observation, physical therapy, injection, surgery, ablation or medication. Integrate symptoms, examination, other imaging findings, duration, prior care and patient goals.",
    "antibiotic_evidence": "The 2019 AIM randomized trial found no clinically important one-year benefit from three months of amoxicillin in its selected chronic-low-back-pain population. A 2026 Cochrane review found only low-certainty slight-to-small short-term pain benefit and small-to-moderate disability benefit in selected patients with type 1 change plus disc herniation, with very uncertain harms; a Modic image is therefore not a standalone antibiotic indication.",
    "stewardship_rule": "Do not recommend or prescribe antibiotics from the type alone. Suspected spinal infection follows an infection workup; experimental or selected chronic-pain antibiotic evidence requires specialist clinical judgment and antimicrobial stewardship."
  },
  "longitudinal_rules": {
    "preserve_trajectory": "Record prior and current component types and extents at each level; mixed change can evolve in more than one direction and should not be reduced to a presumed fixed sequence 1-to-2-to-3.",
    "technical_change": "Before calling conversion or enlargement, check sequence comparability and fat suppression.",
    "clinical_change": "New fever, bacteremia risk, severe rest/night pain, neurologic deficit or rapidly destructive morphology overrides a routine degenerative follow-up interpretation."
  },
  "agent_output_contract": [
    "each_disc_level_and_each_adjacent_endplate",
    "pure_mixed_or_indeterminate_Modic_phenotype",
    "T1_and_non_fat_suppressed_T2_signal_evidence",
    "spatial_extent_and_distribution",
    "sequence_and_comparison_adequacy",
    "disc_endplate_paraspinal_epidural_and_sclerotic_companions",
    "infection_fracture_inflammatory_and_tumor_differential_when_relevant",
    "no_pain_generator_prognosis_or_treatment_inference_from_type_alone"
  ],
  "missing_input_behavior": [
    "If conventional T1 is unavailable, do not assign type 1 versus type 2 from fluid-sensitive imaging alone.",
    "If only fat-suppressed T2/STIR is available, do not assign type 2 versus type 3 from low signal; return sequence-limited.",
    "If two tissue patterns coexist, return a mixed type and map each component instead of selecting one code.",
    "If destructive endplate, disc, paraspinal or systemic features raise infection, return Modic-versus-infection uncertainty and prioritize the safety differential.",
    "If symptoms and examination are absent, report morphology only and withhold pain causality and management conclusions."
  ],
  "supporting_sources": [
    {
      "role": "primary_types_1_and_2",
      "citation": "Modic et al. Radiology. 1988;166:193-199",
      "doi": "10.1148/radiology.166.1.3336678",
      "pmid": "3336678"
    },
    {
      "role": "type_3_and_imaging_context",
      "citation": "Modic et al. Radiology. 1988;168:177-186",
      "doi": "10.1148/radiology.168.1.3289089",
      "pmid": "3289089"
    },
    {
      "role": "reporting_recommendations",
      "citation": "Fields et al. Eur Spine J. 2019;28:2266-2274",
      "doi": "10.1007/s00586-019-06119-6",
      "pmcid": "PMC7205555"
    },
    {
      "role": "pain_association_limit",
      "citation": "Herlin et al. PLoS One. 2018;13:e0200677",
      "doi": "10.1371/journal.pone.0200677",
      "pmcid": "PMC6070210"
    },
    {
      "role": "infection_differential",
      "citation": "Patel et al. AJNR. 2014;35:1647-1652",
      "doi": "10.3174/ajnr.A3948",
      "pmcid": "PMC7964436"
    },
    {
      "role": "antibiotic_randomized_trial",
      "citation": "Bråten et al. BMJ. 2019;367:l5654",
      "doi": "10.1136/bmj.l5654",
      "pmcid": "PMC6812614"
    },
    {
      "role": "current_antibiotic_synthesis",
      "citation": "Liu et al. Cochrane Database Syst Rev. 2026;4:CD014221",
      "doi": "10.1002/14651858.CD014221.pub2",
      "pmid": "41944232"
    }
  ],
  "source_locator": "Modic et al. 1988, DOI 10.1148/radiology.166.1.3336678, abstract and histologic correlation for types 1-2; Modic et al. 1988, DOI 10.1148/radiology.168.1.3289089 for type 3; Fields et al. 2019, PMC7205555, Recommendations and Tables for acquisition, measurement, mixed types and reporting; Herlin et al. 2018, PMC6070210, Results/Conclusions for inconsistent pain associations; Patel et al. 2014, PMC7964436, Methods/Results for the DWI claw sign; Bråten et al. 2019, PMC6812614, Results/Conclusions; Liu et al. 2026 Cochrane review, DOI 10.1002/14651858.CD014221.pub2, Authors' conclusions."
}