Acute or Degenerative? How to Read the MRI Report in a Bodily Injury Claim

Causation arguments in bodily injury claims often narrow to one sentence in the impression section of an MRI report. This is a reading guide to that document for adjusters without a clinical background.

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The causation fight usually turns on one line

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A demand says the collision caused a herniated disc. The MRI report says something else. "Multilevel degenerative disc disease with disc desiccation and endplate osteophytes; no acute osseous abnormality." Both sentences describe the same spine. Report wording in this article is illustrative, written to show the pattern rather than quoted from a real file.

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The adjuster does not need to resolve that. A physician does. The adjuster needs to read the report accurately enough to do three things. Identify the line in dispute, state what it says, and frame the question for the reviewing physician.

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This is not a clinical guide, and nothing here supports diagnosing a claimant or overriding a radiologist. It is a reading guide for the document. Where the load-bearing sentence sits, which words point to time, and how a post-accident study gets compared with earlier imaging.

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Where the argument lives in the report

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A radiology report has a fixed shape. The American College of Radiology sets the expected content in its practice parameter for communicating imaging findings, revised in 2025. Two of its elements decide most causation arguments.

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On the impression, the parameter is direct. "Unless the report is brief, each report should contain an 'impression' or 'conclusion.'" It adds that "a specific diagnosis should be given when possible" (ACR Practice Parameter for Communication of Diagnostic Imaging Findings). On prior studies it is softer. Comparison with relevant examinations "should be part of the radiologic consultation and report when appropriate and available" (ACR Practice Parameter for Communication of Diagnostic Imaging Findings).

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Findings and impression do different jobs

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The findings section is an inventory. It lists everything the radiologist sees, level by level, without ranking it. A long findings section is not a severe injury. It is a thorough reader.

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The impression is the radiologist's conclusion about what matters. It is the sentence the treating physician acts on, the sentence plaintiff's counsel quotes, and the sentence the defense expert is asked about. When the two sections disagree in emphasis, that gap is worth a question.

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The comparison line tells you whether anything was compared

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Near the top, a report states what it was compared against. A prior MRI, a radiograph, a CT, or "none available." That line decides how much the study can prove about change over time.

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"No prior comparison" means the radiologist described a spine at one moment. Any statement about what the spine looked like before the loss came from somewhere else, or from inference.

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Words that describe time: the chronic vocabulary

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Degenerative change develops slowly. One radiology review calls spine degeneration "a biomechanically related continuum of alterations evolving over time" (ABCs of the degenerative spine, Insights into Imaging, 2018). Findings from that continuum did not appear in the seconds of a collision.

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None of these terms is a date stamp. They describe processes that develop slowly, which is a different thing from saying when a process began. T2 below refers to a standard MRI sequence on which fluid appears bright.

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• Disc desiccation. What it describes: Loss of water content in the disc centre, seen as a dark disc on T2 images. What it suggests about timing: Gradual; a marker of degeneration, not of a single event.
• Disc space narrowing / height loss. What it describes: The vertebrae have moved closer together. What it suggests about timing: Gradual, follows desiccation.
• Osteophyte, spondylosis. What it describes: Bony outgrowth at the endplates or facet joints. What it suggests about timing: Bone remodeling, which the imaging literature treats as slow.
• Endplate sclerosis. What it describes: Dense bone at the disc margin. What it suggests about timing: Remodeling, not a same-day finding.
• Facet arthropathy / hypertrophy. What it describes: Wear and enlargement of the facet joints. What it suggests about timing: Gradual.
• Modic type 2 changes. What it describes: Fatty marrow signal next to the endplate. What it suggests about timing: The stable, chronic stage.
• "No acute findings". What it describes: Nothing the radiologist reads as recent. What it suggests about timing: Argues against a fresh bone or marrow injury.

Disc desiccation and height loss

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A healthy disc holds water and appears bright on T2-weighted images. As it degenerates, the nucleus "becomes desiccated resulting in reduced intradiscal pressure." That loss of pressure then produces disc space narrowing and bulging (ABCs of the degenerative spine).

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A dark, flattened disc is a disc that has been changing for a long time. It is not a photograph of an impact.

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Osteophytes and spondylosis

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Osteophytes are bone. Bone remodels slowly. The same review defines spondylosis as a "common nonspecific term used to describe hypertrophic changes of the end plates (osteophytes) and facet joints" (ABCs of the degenerative spine).

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A ten-year imaging follow-up of the DESIR cohort found that degenerative spinal lesions "appear to progress slowly." The reported rate in that cohort was roughly 1 percent per year (European Radiology, 2025). Those patients were followed for axial spondyloarthritis, so the population is not a claims population. The timescale is the point. Established bony change on a study taken weeks after a loss is generally consistent with a process that began earlier. The reviewing physician is the one who says so.

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Modic changes, and why the type matters

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Modic changes are signal changes in the marrow next to a degenerated disc. The classification carries timing information that the word "changes" hides.

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Type 1 is an edema-like signal. It corresponds to the active, inflammatory stage of disc degeneration. Type 2 is a fat-like signal and represents "a more stable and chronic process." Type 1 changes convert to type 2 over time (AJNR review of Modic endplate and marrow changes, 2008). Type 3 is sclerotic.

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"Modic type 2 at L5-S1" is a chronic marker. "Modic type 1" describes an active marrow process next to a degenerated disc. Whether it has any relationship to the loss is a question for the reviewing physician, not an argument either side can close on.

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"No acute findings" and what it excludes

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This phrase is narrower than it sounds. It usually means no fracture, no marrow edema, no cord compression, no epidural collection. It does not mean no injury. Soft tissue injury, an aggravated degenerative segment, and a symptomatic disc can all sit behind that sentence.

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Read the rest of the impression before treating the phrase as a defense verdict.

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Words that describe time: the acute vocabulary

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A short list of findings genuinely points to something recent.

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• Bone marrow edema in a fractured vertebra. In compression fractures this is the marker radiologists rely on. "Bone marrow edema is indicative of the acute phase of the fracture." Chronic fractures "generally show resolution of edema on MRI" (Journal of Imaging, 2024).
• STIR or fat-saturated sequences. These sequences make marrow edema visible. If the report lists none, the study was less able to separate a new fracture from an old one.
• A fracture with an acute descriptor. "Acute compression fracture" and "fracture with associated marrow edema" carry timing. "Old compression deformity" and "age-indeterminate" do not.

Two cautions belong with that list. Marrow edema is not unique to trauma: Modic type 1 endplate change is also an edema-like signal arising from degeneration, as the section above describes. And the absence of an acute finding does not disprove an injury, because soft tissue injury often leaves no imaging signature at all.

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Separately, findings such as nerve root or cord compression speak to severity rather than timing. They matter to the value of the claim, not to the date of the injury.

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Shape words are not cause words

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Bulge, protrusion and extrusion describe the shape of displaced disc material. An annular fissure is something different: a defect in the fibrous outer ring of the disc, not a displacement. It is easy to read these terms as a scale of trauma. The nomenclature that radiologists use says otherwise.

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Three specialty bodies set that nomenclature: the North American Spine Society, the American Society of Spine Radiology and the American Society of Neuroradiology. Their combined task forces state that the definitions "are not intended to imply external etiologic events such as trauma." The definitions also "do not imply relationship to symptoms" (Lumbar Disc Nomenclature: Version 2.0).

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Two practical consequences:

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1. "Extrusion" and "protrusion" are separated by the shape of the displaced material, measured against the width of its base. Neither term states how the displacement arose.
2. The task forces emphasise "annular fissure" in place of "annular tear" (Lumbar Disc Nomenclature: Version 2.0). A report that still says "tear" is using the older word, which on its own settles nothing about cause.

The same caution applies to prevalence. A pooled review of studies of asymptomatic people found disc degeneration in 37 percent of 20-year-olds and 96 percent of 80-year-olds. Disc bulges ran from 30 percent to 84 percent across the same ages (Brinjikji et al., AJNR, 2015). Findings that common are not, by themselves, evidence of a traumatic event.

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Comparing the post-accident MRI with earlier imaging

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A single study describes a state. Two studies describe a change. Change is what causation arguments need.

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What counts as a prior study

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Prior imaging is rarely another spine MRI. It is more often a chest CT that covered the thoracic spine, or a lumbar radiograph from an urgent care visit years earlier. It can be a cervical radiograph from an emergency department, or spine imaging from an unrelated workers' compensation file. Those studies tend to be named in records the file already holds, rather than in the imaging report itself.

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Build the imaging list from the chronology, not from the demand package. An imaging history that never appears on a date-ordered medical chronology tends to be missed entirely.

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What a real comparison produces

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A radiologist comparing two studies writes in the language of change. "New," "increased," "unchanged," "stable," "progressed," "interval development of." Those words are the evidence. A line reading "unchanged disc protrusion at L4-L5 compared with the 2023 study" beats any argument about prevalence, provided the 2023 study predates the loss.

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If the current report names a prior study but says nothing about change, the comparison may have been nominal. Requesting a formal comparison read, with both studies in front of the radiologist, is a reasonable step on a large file.

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When no prior imaging exists

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This is the common case. Many claimants have never had spine imaging before the loss, so there is nothing to compare against. The absence of a prior study is not evidence either way. It moves the question back to the records. Prior complaints about the same body part, prior treatment, the mechanism described at the first visit, and the gap before care began. The same records-first method appears in causation analysis in premises liability claims.

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What one line in the impression can support

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An impression line is a radiologist's opinion about images. It is not a causation opinion, and it usually does not claim to be.

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The impression wording quoted below is illustrative. L5-S1 and T12 are spinal levels; "osseous" means bony.

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• "Disc extrusion at L5-S1 contacting the traversing S1 nerve root". A fair reading: The report describes a nerve root finding; whether it fits the reported symptoms is for the physician reviewer. An unfair reading: The collision caused the extrusion.
• "Multilevel degenerative disc disease; no acute osseous abnormality". A fair reading: No fresh bone injury seen on this study. An unfair reading: No injury occurred.
• "Disc protrusion, unchanged from the 2022 examination". A fair reading: Evidence the finding was already present in 2022, and so predates any later loss. An unfair reading: The claimant has no injury at all.
• "Marrow edema at T12 consistent with acute compression fracture". A fair reading: Imaging support for a recent fracture at that level. An unfair reading: Support for every other complaint in the demand.
• "Acute on chronic changes" or "clinical correlation recommended". A fair reading: The radiologist has declined to separate old from new; the question stays open. An unfair reading: Either side's preferred half of the phrase.

Three questions turn a report into a usable position:

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1. Which findings on this study are dated by the imaging itself, and which are undated?
2. Was any prior imaging compared, and if not, does any exist anywhere in the file?
3. Does the impression address causation, or is it being read as though it does?

Those questions belong to the physician reviewer. The adjuster's job is to attach the whole imaging history to those questions, not the single study the demand included. Assembling that history across hundreds of pages is what AI tools for bodily injury claim files are aimed at. The condition is provenance. Each extracted finding must link back to the report page it came from, so the reviewer reads the source before relying on it.

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What the impression can and cannot settle

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Causation disputes narrow to one sentence more often than they should. That sentence is usually in the impression, and it is usually undated.

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An adjuster who can read the report can sort its sentences. Which part is a timing statement, which part is a shape description, and which part is a conclusion about images rather than about the claim. That is enough to frame the question and put the right studies in front of a reviewing physician. It is also enough to stop conceding a causation argument the report never made.

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Key takeaways

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• The findings section is an inventory; the impression is the radiologist's conclusion and the sentence both sides will quote. The comparison line near the top tells you whether any earlier imaging was actually reviewed.
• Chronic vocabulary: disc desiccation, disc space narrowing, osteophytes, endplate sclerosis, facet arthropathy and Modic type 2 changes all describe slow processes. None of them is a date stamp.
• Acute vocabulary is short: marrow edema in a fractured vertebra, STIR or fat-saturated sequences that can show it, and a fracture described as acute. Marrow edema is not unique to trauma, and no acute finding does not mean no injury.
• Bulge, protrusion and extrusion describe shape, not cause. The specialty task forces that set the nomenclature state that the definitions do not imply trauma or a relationship to symptoms.
• Two studies prove change; one study proves a state. Build the imaging list from the chronology, and send the whole imaging history to the physician reviewer rather than the single study attached to the demand.

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