Spine Imaging

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Spine Anatomy & Modalities - Atlas & The Scanners

  • Key Anatomy:
    • Vertebral segments: Cervical (7), Thoracic (12), Lumbar (5).
    • Atlas (C1): Ring-shaped, no body.
    • Axis (C2): Odontoid process (dens).
    • Spine Anatomy: Vertebrae, Ligaments, and Regions
  • Imaging Scanners:
    • X-ray: First line for trauma, alignment. Views: AP, Lateral, Odontoid.
    • CT: Superior for bone detail, complex fractures.
    • MRI: Best for spinal cord, discs, nerves, ligaments. Key sequences: T1W, T2W, STIR.
      • 📌 T2W: CSF/water is bright (hyperintense).

⭐ Jefferson fracture (C1 burst fracture) results from axial loading; assess transverse ligament integrity using "Rule of Spence" on open-mouth odontoid view.

Spinal Trauma - When Spines Snap

  • Initial Imaging: X-ray (trauma series) if CT unavailable. CT is gold standard for bony injury. MRI for cord, ligaments, soft tissues.
  • Stability: Denis 3-column theory (Anterior, Middle, Posterior). Instability if ≥2 columns involved.
  • Cervical Fractures: Jefferson (C1 burst), Hangman's (C2 bilateral pedicle #), Odontoid (Type II unstable).
  • Thoracolumbar Fractures: Compression (anterior column), Burst (all 3 columns, retropulsion), Chance (flexion-distraction, seatbelt injury).
  • SCIWORA: Spinal Cord Injury Without Radiographic Abnormality, esp. in children.

⭐ MRI is crucial for detecting ligamentous injury, a key determinant of spinal instability, even with normal CT.

Axial CT C1 Jefferson fracture

Degenerative Spine Disease - The Ageing Spine's Tale

  • Spondylosis: Osteophyte formation, disc space narrowing, endplate sclerosis.
  • Disc Degeneration:
    • Desiccation (↓T2 signal), height loss, vacuum phenomenon.
    • Herniation: bulge, protrusion, extrusion, sequestration.
    • Annular fissures/tears.
  • Facet Joint Arthropathy: Hypertrophy, osteophytes, joint effusion, subchondral cysts.
  • Ligamentum Flavum: Hypertrophy, buckling, ossification.
  • Spinal Stenosis:
    • Central canal, lateral recess, or foraminal narrowing.
  • Degenerative Spondylolisthesis: Anterior vertebral slippage (common at L4-L5).

⭐ Modic changes (vertebral endplate signal alterations): Type I (edema: ↓T1, ↑T2), Type II (fatty marrow: ↑T1, ↑T2), Type III (sclerosis: ↓T1, ↓T2).

Spinal Infections & Inflammation - Fiery Spine Foes

  • Pyogenic Spondylodiscitis: S. aureus (MC). Hematogenous. Rapid disc destruction. MRI: T1↓, T2↑ disc/vertebrae, enhancement, abscess.
  • Tuberculous Spondylitis (Pott's Spine): Thoracolumbar. Relative disc preservation (early). MRI: Subligamentous spread, large cold abscess, gibbus.

    ⭐ Pott's spine: Often multiple vertebral bodies, relative disc preservation (early), large cold abscess, subligamentous spread.

  • Brucellar Spondylitis: Pedro Pons sign (anterior osteophytes), disc involvement.
  • Ankylosing Spondylitis (AS): HLA-B27. Sacroiliitis (earliest sign, bilateral, symmetrical), syndesmophytes, bamboo spine. MRI spine: Spondylodiscitis/Pott's spine featuresoka

Spinal Tumors & Mimics - Unwanted Spine Guests

  • Metastases (Mets): Most common malignant spinal tumors.
    • Sources: Lung, breast, prostate, kidney, thyroid (📌 "BLT Kosher Pickle": Breast, Lung, Thyroid, Kidney, Prostate).
    • Appearance: Lytic (commonest), blastic (prostate, breast), mixed.
    • "Winking owl sign" (pedicle loss). Ivory vertebra (diffuse sclerosis).
  • Multiple Myeloma: Punched-out lytic lesions, diffuse osteopenia.
  • Primary Tumors:
    • Osteoid Osteoma: Nocturnal pain, NSAID relief. Nidus <1.5 cm.
    • Chordoma: Sacrococcygeal/clival, T2 hyperintense, locally aggressive.
  • Mimics:
    • Infection (TB/Pott's): Discitis, vertebral body destruction, paraspinal abscess.
    • Degenerative: Modic changes, Schmorl's nodes.

⭐ Vertebral metastases are the most common malignant tumors of the spine, frequently from breast, lung, or prostate primaries.

High‑Yield Points - ⚡ Biggest Takeaways

  • MRI: modality of choice for spinal cord, discs, infections, tumors.
  • X-rays: initial for trauma, spondylolisthesis, scoliosis. Flexion-extension for instability.
  • CT: superior for bony anatomy, complex fractures, osseous stenosis.
  • Spondylolysis ("pars defect"): "Scotty dog" sign (X-ray); CT/SPECT confirms.
  • T1W MRI: CSF dark, fat bright. T2W MRI: CSF bright, fat bright (unless suppressed).
  • STIR sequence: best for bone marrow edema (fractures, osteomyelitis) by nulling fat.
  • Vertebral hemangiomas: T1 & T2 hyperintense; "corduroy" or "polka dot" signs.

Practice Questions: Spine Imaging

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Which imaging modality is LEAST useful in the initial diagnosis of stress fractures?

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Flashcards: Spine Imaging

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The _____ sign is seen in spinal metastases.

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The _____ sign is seen in spinal metastases.

winking owl

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