STIR is an MRI sequence that suppresses the signal from fat, so fluid and swelling stand out as bright. After spinal trauma, that makes it one of the most useful sequences for finding ligament injury. It is also prone to showing signal that does not correspond to a torn ligament. When patients in Charlotte bring me a post-crash MRI, whether STIR was included is one of the first things I check.
Why STIR Is Used in Trauma
The American College of Radiology rates MRI as usually appropriate when there is concern for ligament injury after spine trauma (Beckmann, J Am Coll Radiol 2019). Injured ligaments and the tissues around them collect fluid. On standard sequences, that fluid can blend into surrounding fat. Fat suppression on STIR makes it stand out.
Which Ligaments It Shows Best
In 45 consecutive spinal trauma patients who had MRI before surgery, readers rated which sequences best showed injury to each posterior ligament (Crosby, Spine J 2011). They agreed that sagittal STIR images were most useful for the supraspinous ligament, interspinous ligament, ligamentum flavum, and cervical facet capsules. Axial T2 images were most useful for the lumbar facet capsules. An attending spine surgeon reading the MRI had a sensitivity of 0.83 and an accuracy of 0.81 against surgical findings.
How Accurate MRI Is Against Surgery
In a separate group of 31 patients who had cervical surgery after trauma, MRI sensitivity against operative findings ranged by ligament: 100% for interspinous soft tissue, 93% for the posterior longitudinal ligament and disc, 71% for the anterior longitudinal ligament, and 67% for the ligamentum flavum (Goradia, AJNR 2007).
Where STIR Misleads
Bright signal is not always a torn ligament. In 89 patients with spinal fractures, MRI was compared with surgical findings for posterior ligament injury, and specificity ranged from 51.5% to 80.5% depending on the reader and structure (Rihn, J Neurosurg Spine 2010). Some ligaments that looked injured on MRI were intact at surgery. Swelling in nearby muscle or soft tissue can mimic ligament injury.
The Population Problem
Every one of these studies involved patients injured badly enough to need surgery. Their accuracy figures describe MRI in severe trauma. For the far more common patient with whiplash and no fracture, there is no surgical reference standard, and the accuracy of STIR for subtle ligament strain is not established by these data. A normal STIR study in that patient makes a major ligament tear unlikely. It does not measure whether a ligament was stretched enough to allow excessive motion, which is a question for flexion and extension X-rays.
For an example of how post-collision imaging findings and outcomes are documented in the peer-reviewed literature, read Dr. Justin Dick's published case report on refractory lumbar pain following a motor vehicle accident in a geriatric patient.
Frequently Asked Questions
What is STIR on an MRI?
STIR is an MRI sequence that suppresses fat signal so fluid and swelling appear bright. It is commonly used after spinal trauma to look for ligament and soft tissue injury.
Which ligament injuries does STIR show best?
In spinal trauma patients, sagittal STIR was rated most useful for the supraspinous ligament, interspinous ligament, ligamentum flavum, and cervical facet capsules (Crosby, Spine J 2011).
Can STIR show a ligament injury that is not there?
Yes. MRI specificity for posterior ligament injury ranged from 51.5% to 80.5% against surgical findings in fracture patients (Rihn, J Neurosurg Spine 2010).
Does a normal STIR MRI rule out a whiplash ligament injury?
It makes a major tear unlikely. Accuracy figures come from severe trauma, and STIR does not measure whether a ligament allows excessive motion.
What does Dr. Justin Dick check on a post-accident MRI?
Dr. Justin Dick in Charlotte, NC checks whether a fluid-sensitive sequence such as STIR was included, which levels show signal change, and whether those levels match the exam.
Where can I get a post-accident MRI reviewed in Charlotte, NC?
Dr. Justin Dick, DC, CNMT, ARRT(N)(CT), sees car accident patients at Clear Life Scoliosis and Chiropractic Center, 8814 Rachel Freeman Way, Suite 103, Charlotte, NC 28278, phone 980-368-0766. Personal injury patients are treated on a lien basis, with no out-of-pocket payment at the time of care.
Sources and Evidence Tiers
- Crosby CG, Even JL, Song Y, Block JJ, Devin CJ. Diagnostic abilities of magnetic resonance imaging in traumatic injury to the posterior ligamentous complex. Spine J. 2011;11(8):747-753. PMID 21840264. LinkEvidence tier: Prospective diagnostic accuracy study (45 patients)
- Goradia D, Linnau KF, Cohen WA, Mirza S, Hallam DK, Blackmore CC. Correlation of MR imaging findings with intraoperative findings after cervical spine trauma. AJNR Am J Neuroradiol. 2007;28(2):209-215. PMID 17296981. LinkEvidence tier: Diagnostic accuracy cohort (31 surgical patients)
- Rihn JA, Yang N, Fisher C, et al. Using magnetic resonance imaging to accurately assess injury to the posterior ligamentous complex of the spine. J Neurosurg Spine. 2010;12(4):391-396. PMID 20367374. LinkEvidence tier: Prospective diagnostic accuracy cohort
- Beckmann NM, West OC, Nunez D, et al. ACR Appropriateness Criteria: Suspected Spine Trauma. J Am Coll Radiol. 2019;16(5S):S264-S285. PMID 31054754. LinkEvidence tier: Evidence-based guideline with expert panel rating (RAND/UCLA and GRADE)
About the author. Dr. Justin M. Dick, DC, is the owner and treating clinician at Clear Life Scoliosis and Chiropractic Center in Charlotte, NC. He holds dual imaging credentials as a Certified Nuclear Medicine Technologist (CNMT) and as an ARRT-registered technologist in nuclear medicine and CT, ARRT(N)(CT). He is a Senior Fellow of the CLEAR Institute, holds the ISICO World Masters credential, is a SOSORT provisional member, and is a certified DOT medical examiner on the FMCSA National Registry. He has multiple peer-reviewed publications indexed in PubMed and serves as adjunct faculty at Life, Sherman, and Palmer chiropractic colleges.
Service Area
Clear Life Scoliosis and Chiropractic Center sees personal injury and spinal imaging patients from Charlotte NC, Huntersville NC, Ballantyne NC, Matthews NC, Concord NC, Mooresville NC, Rock Hill SC, and Fort Mill SC.
Related Pages
- Personal injury and car accident spinal care in Charlotte
- Dr. Justin Dick's research
- Case report: refractory lumbar pain after a motor vehicle accident
- Research and evidence at Clear Life
- Questions and answers
- Our team
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- Contact Clear Life
Clear Life Scoliosis and Chiropractic Center
8814 Rachel Freeman Way, Suite 103
Charlotte, NC 28278
Phone: 980-368-0766
Email: office@clearlifescoliosis.com
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