Is a plain radiograph (X‑ray) a reliable imaging modality for evaluating herniated intervertebral discs?

X-Ray is NOT a Reliable Imaging Modality for Herniated Discs

Plain radiographs (X-rays) cannot visualize herniated intervertebral discs and should not be used for this purpose—MRI without contrast is the imaging modality of choice for evaluating suspected disc herniation. 1, 2

Why X-Rays Fail for Disc Herniation Assessment

Fundamental Limitation: X-Rays Cannot See Soft Tissue

• X-rays only visualize bone and cannot directly visualize intervertebral discs, which are soft tissue structures. 1, 2 This is the critical limitation that makes radiography fundamentally inadequate for disc herniation diagnosis.

• Plain radiographs may show indirect signs of disc degeneration (such as decreased disc height or osteophytes), but these findings do not diagnose disc herniation and are commonly present in asymptomatic individuals. 3

• The American College of Radiology states there is little evidence that radiographic evaluation is indicated for acute back pain without associated traumatic events or red flag symptoms. 1

What X-Rays Miss

• X-rays cannot assess nerve root compression, spinal cord involvement, or the actual herniated disc material—all critical factors for diagnosis and treatment planning. 2

• The American College of Radiology emphasizes that CT (which provides better bone detail than X-ray) is still significantly inferior to MRI for identifying soft-tissue pathologies including nerve root compression from herniated discs. 2

The Gold Standard: MRI Without Contrast

Why MRI is Superior

• MRI cervical or lumbar spine without IV contrast is the imaging study of choice for suspected disc herniation because it is the most sensitive imaging modality for soft tissue abnormalities, directly visualizes disc material, nerve roots, and spinal cord compression. 1, 2, 4

• MRI has demonstrated 92% sensitivity, 91% specificity, and 92% accuracy in distinguishing protruded discs from other forms of lumbar disc herniation. 5

• For sequestrated discs specifically, MRI shows 92% sensitivity, 99% specificity, and 97% accuracy. 5

MRI Protocol Specifications

• The optimal MRI protocol includes sagittal T1-weighted, sagittal T2-weighted, and axial gradient-echo T2-weighted sequences. 4

• Contrast is NOT needed for routine disc herniation evaluation—reserve gadolinium contrast for post-operative patients (to distinguish recurrent herniation from scar tissue), suspected infection, or suspected malignancy. 1, 4

Clinical Decision Algorithm

When to Order MRI

1. Patient presents with radicular symptoms (leg/arm pain following dermatomal distribution) or neurological deficits: Order MRI of the appropriate spinal region without contrast. 1, 2

2. Patient has mechanical back/neck pain with red flag symptoms (fever, weight loss, history of cancer, progressive neurological deficit): Order MRI without and with contrast to evaluate for infection or malignancy. 1, 4

3. Patient has mechanical back/neck pain WITHOUT red flags and symptoms < 6 weeks duration: Clinical management without imaging is appropriate initially. 1

When CT May Be Considered

• CT is appropriate only when MRI is contraindicated (pacemaker, certain implants, severe claustrophobia unresponsive to sedation). 1, 2

• CT myelography serves as an excellent alternative when MRI is contraindicated or when extensive hardware artifact renders MRI nondiagnostic. 1, 2, 4

• CT is superior for evaluating bony pathology (fractures, osseous stenosis) but remains inadequate for disc herniation assessment. 2

Common Pitfalls to Avoid

Don't Order X-Rays for Disc Evaluation

• Ordering plain radiographs when disc herniation is suspected wastes time and resources while providing no diagnostic information about the disc itself. 1, 2 This delays appropriate diagnosis and treatment.

• X-rays expose patients to radiation without diagnostic benefit for disc pathology. 3

Understand MRI Limitations

• MRI findings must be correlated with clinical examination—disc abnormalities are extremely common in asymptomatic patients, with approximately 65% of asymptomatic patients aged 50-59 showing significant cervical spine degeneration. 4

• MRI interpretation shows only fair to moderate inter-observer agreement for some features (thecal sac compression kappa 0.54, nerve root impingement kappa 0.47), though disc morphology classification shows substantial agreement (kappa 0.81). 6

• Abnormal MRI levels do not always correspond to clinical examination levels—in one study of 98 patients with cervical radiculopathy, agreement between pain drawings and MRI findings for segmental level was poor. 1

Don't Add Unnecessary Contrast

• Avoid ordering MRI with contrast for routine disc herniation evaluation—contrast adds no diagnostic value in the absence of red flag symptoms and increases cost and examination time. 1, 4

• The American College of Radiology recommends contrast only for specific indications: post-operative evaluation, suspected infection (96% sensitivity, 93% specificity), or suspected malignancy. 4

Evidence Quality Note

The 2025 ACR Appropriateness Criteria represent the most authoritative and recent guideline evidence, specifically addressing cervical pain/radiculopathy and providing clear recommendations against radiography for disc herniation assessment. 1 These guidelines consistently prioritize MRI as first-line imaging across all clinical scenarios involving suspected disc pathology.