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Question 1: Cervical Spine Trauma (Jefferson Fracture)

Stem: A 30-year-old man is brought to the emergency department after diving into a shallow pool and hitting his head. A CT scan of the cervical spine shows comminuted fractures of both the anterior and posterior arches of the C1 vertebra (Atlas), with lateral displacement of the C1 lateral masses.

Question: What is the eponym for this unstable fracture?

(A) Hangman’s Fracture (B) Jefferson Fracture (C) Odontoid Fracture (Type II) (D) Flexion Teardrop Fracture (E) Clay-Shoveler’s Fracture

Correct Answer: (B) Jefferson Fracture.

Explanation:

  • Why (B) is correct: A Jefferson fracture is a burst fracture of the C1 ring (Atlas), classically involving fractures of both the anterior and posterior arches. It is caused by axial loading (e.g., diving). The key sign on an open-mouth view or CT is the bilateral lateral displacement of the C1 lateral masses relative to C2.
  • Why (A) is wrong: A Hangman’s fracture is a fracture through the bilateral pars interarticularis of C2.
  • Why (C) is wrong: An odontoid fracture is a fracture of the dens of C2.
  • Why (D) is wrong: A flexion teardrop fracture involves an avulsion of the anteroinferior vertebral body, typically at C5-C7.
  • Why (E) is wrong: A clay-shoveler’s fracture is a stable avulsion fracture of a spinous process, most commonly C7.

Key Points: Jefferson Fracture (C1)

  • Mechanism: Axial loading.
  • Description: A “burst” fracture of the C1 ring.
  • Findings: Involves both anterior and posterior arches.
  • Stability: Unstable, especially if the transverse ligament is ruptured (indicated by >7 mm combined lateral mass displacement on an open-mouth view).

Question 2: Cervical Spine Trauma (Hangman’s Fracture)

Stem: A 50-year-old man is involved in a high-speed motor vehicle collision. A CT of the cervical spine reveals bilateral fractures through the pars interarticularis of C2 (Axis), with associated anterolisthesis of the C2 body on C3.

Question: What is the eponym for this unstable fracture?

(A) Hangman’s Fracture (B) Jefferson Fracture (C) Odontoid Fracture (Type III) (D) Extension Teardrop Fracture (E) Atlanto-occipital Dislocation

Correct Answer: (A) Hangman’s Fracture.

Explanation:

  • Why (A) is correct: This is the classic description of a Hangman’s fracture (also known as traumatic spondylolisthesis of C2). The mechanism is hyperextension and distraction/compression (e.g., hitting the chin on a steering wheel). It is a fracture of the bilateral pars interarticularis of C2.
  • Why (B) is wrong: A Jefferson fracture is a burst fracture of C1.
  • Why (C) is wrong: An odontoid fracture involves the dens, not the pars of C2.
  • Why (D) is wrong: An extension teardrop fracture is an avulsion of the anteroinferior C2 body and is different from a pars fracture.
  • Why (E) is wrong: This is a catastrophic, highly fatal ligamentous injury at the C0-C1 level.

Key Points: Hangman’s Fracture (C2)

  • Mechanism: Hyperextension.
  • Description: Fracture through the bilateral pars interarticularis of C2.
  • Stability: Unstable.
  • Classification: The Effendi classification is used to grade the displacement and angulation.

Question 3: Cervical Spine Trauma (Flexion Teardrop)

Stem: A 20-year-old man sustains a severe hyperflexion injury in a rugby tackle and is tetraplegic. A CT scan of the cervical spine shows a fracture of the anteroinferior corner of the C5 vertebral body, which is displaced anteriorly. The scan also shows posterior displacement of the C5 vertebral body into the spinal canal and disruption of the posterior ligaments.

Question: What is the most likely diagnosis for this highly unstable injury?

(A) Simple Wedge Fracture (B) Clay-Shoveler’s Fracture (C) Flexion Teardrop Fracture (D) Extension Teardrop Fracture (E) Hangman’s Fracture

Correct Answer: (C) Flexion Teardrop Fracture.

Explanation:

  • Why (C) is correct: A flexion teardrop fracture is the most severe, unstable cervical spine injury. It is caused by severe flexion and compression. It has two key components: 1) A “teardrop” fragment from the anteroinferior vertebral body, and 2) Posterior displacement of the main vertebral body into the spinal canal, causing catastrophic cord injury.
  • Why (A) is wrong: A simple wedge fracture involves only anterior compression and is stable. It does not involve posterior displacement.
  • Why (B) is wrong: This is a stable fracture of the spinous process.
  • Why (D) is wrong: An extension teardrop fracture is an avulsion of the anteroinferior corner (classically at C2) from hyperextension. It is stable in flexion but unstable in extension. It does not cause posterior displacement.
  • Why (E) is wrong: This is a fracture of the C2 pars.

Key Points: Flexion Teardrop Fracture

  • Mechanism: Severe flexion and compression.
  • Hallmark: The most unstable cervical spine fracture.
  • Findings:
    1. Anteroinferior corner “teardrop” fragment.
    2. Posterior displacement of the vertebral body into the canal.
    3. Complete disruption of all ligaments.
  • Consequence: Almost always results in anterior cord syndrome and tetraplegia.

Question 4: Thoracolumbar Trauma (Chance Fracture)

Stem: A 25-year-old woman is a restrained passenger in a front-on car crash. She has acute back pain. A CT scan of the lumbar spine reveals a horizontal fracture that extends through the posterior elements (spinous process, lamina, and pedicles) and continues through the vertebral body of L1.

Question: What is the eponym for this unstable “seatbelt” fracture?

(A) Burst Fracture (B) Compression Fracture (C) Chance Fracture (D) Jefferson Fracture (E) Holdsworth Fracture

Correct Answer: (C) Chance Fracture.

Explanation:

  • Why (C) is correct: A Chance fracture is a flexion-distraction injury, classically seen in passengers wearing a lap-only seatbelt (the “seatbelt fracture”). The entire vertebra is pulled apart horizontally. It is a 3-column injury, involving distraction of the posterior and middle columns and compression of the anterior column.
  • Why (A) is wrong: A burst fracture is from axial compression, causing the vertebral body to “burst” and retropulse fragments into the canal. The posterior elements are intact.
  • Why (B) is wrong: A compression fracture is an anterior wedge injury and is stable.
  • Why (D) is wrong: This is a C1 burst fracture.
  • Why (E) is wrong: Holdsworth described a flexion-rotation injury, which is a different mechanism.

Key Points: Chance Fracture (Flexion-Distraction)

  • Mechanism: Flexion and distraction (e.g., lap seatbelt).
  • Description: A horizontal fracture through all three columns (spinous process, pedicles, body).
  • Stability: Highly unstable.
  • Association: High incidence of associated intra-abdominal injuries (e.g., bowel, mesenteric, or pancreatic injuries) which must be ruled out.

Question 5: Degenerative (Disc Herniation)

Stem: A 45-year-old man presents with right-sided sciatica. An MRI of the lumbar spine is performed. At the L4/L5 level, there is a focal disc displacement. The base of the displaced disc material at the disc space is narrower than the maximal diameter of the displaced fragment itself.

Question: What is the correct terminology for this type of disc herniation?

(A) Disc Protrusion (B) Disc Extrusion (C) Disc Bulge (D) Disc Sequestration (E) Schmorl’s Node

Correct Answer: (B) Disc Extrusion.

Explanation:

  • Why (B) is correct: The key is the relationship between the “neck” (base) and the “dome” (fragment). An extrusion is when the “neck” is narrower than the “dome” (like toothpaste squeezed from a tube).
  • Why (A) is wrong: A protrusion is when the “neck” is wider than the “dome” (a broad-based disc displacement).
  • Why (C) is wrong: A bulge is a generalized, circumferential displacement of the disc beyond the endplates.
  • Why (D) is wrong: A sequestration is an extrusion where the displaced fragment has lost all continuity with the parent disc.
  • Why (E) is wrong: A Schmorl’s node is a vertical herniation through the vertebral endplate into the body.

Key Points: Disc Herniation Terminology

  • Bulge: Circumferential, symmetric extension of the disc.
  • Protrusion: Focal, broad-based (neck > dome).
  • Extrusion: Focal, narrow-based (neck < dome).
  • Sequestration: An extruded fragment that is no longer connected to the parent disc.

Question 6: Degenerative (Modic Changes)

Stem: A 58-year-old woman with chronic low back pain has an MRI. The images show high signal on both T1 and T2-weighted images in the vertebral endplates at L5/S1.

Question: What type of Modic change does this represent?

(A) Modic Type I (B) Modic Type II (C) Modic Type III (D) Schmorl’s Node (E) Limbus Vertebra

Correct Answer: (B) Modic Type II.

Explanation:

  • Why (B) is correct: Modic Type II changes represent fatty/adipose replacement of the bone marrow. Fat has high signal on both T1 and T2 sequences. This is a chronic degenerative change.
  • Why (A) is wrong: Modic Type I represents oedema and inflammation. It appears low on T1 and high on T2 (like an oedema pattern).
  • Why (C) is wrong: Modic Type III represents sclerosis (dense bone). It appears low on both T1 and T2.
  • Why (D) is wrong: A Schmorl’s node is a herniation into the vertebral body.
  • Why (E) is wrong: A limbus vertebra is an unfused apophysis.

Key Points: Modic Endplate Changes

  • Type I: Oedema/Inflammation. Low T1, High T2. (Acute/Subacute).
  • Type II: Fatty Replacement. High T1, High T2. (Chronic).
  • Type III: Sclerosis. Low T1, Low T2. (End-stage).

Question 7: Infection (Discitis-Osteomyelitis)

Stem: A 60-year-old diabetic man presents with 2 weeks of severe, focal back pain, fever, and a raised ESR. An MRI of the lumbar spine with contrast is performed. It shows T2 high signal and enhancement of the L3 and L4 vertebral bodies and the intervening L3/L4 disc. A phlegmonous collection is seen in the anterior epidural space.

Question: What is the most likely diagnosis?

(A) Modic Type I changes. (B) Tuberculous Spondylitis. (C) Pyogenic Spondylodiscitis (Discitis-Osteomyelitis). (D) Metastatic Disease. (E) Scheuermann’s Disease.

Correct Answer: (C) Pyogenic Spondylodiscitis (Discitis-Osteomyelitis).

Explanation:

  • Why (C) is correct: The clinical picture (fever, raised ESR, diabetes) strongly suggests infection. The key imaging feature of pyogenic (bacterial) infection is involvement of the intervertebral disc. The infection starts in the endplate, destroys it, and spreads into the disc, causing T2 high signal and enhancement of the disc and the adjacent vertebral bodies.
  • Why (A) is wrong: Modic Type I changes are degenerative oedema. They would not cause fever/ESR, an epidural abscess, or destroy the disc.
  • Why (B) is wrong: TB (Pott’s disease) spares the disc until late-stage. It spreads sub-ligamentously, causing large paraspinal abscesses and vertebral body collapse.
  • Why (D) is wrong: Metastatic disease also spares the disc, as the disc is avascular. Metastases typically destroy the pedicles and vertebral bodies, leaving the disc intact.
  • Why (E) is wrong: Scheuermann’s is a developmental disorder (kyphosis, Schmorl’s nodes) in adolescents.

Key Points: Pyogenic Spondylodiscitis

  • Pathology: Bacterial infection (usually Staph. aureus).
  • Hallmark: Destruction of the intervertebral disc.
  • MRI Triad:
    1. T2 high signal/enhancement of the disc.
    2. T2 high signal/enhancement of the adjacent vertebral endplates.
    3. Associated paraspinal/epidural abscess or phlegmon.

Question 8: Infection (Tuberculous Spondylitis)

Stem: A 35-year-old man from an endemic region presents with chronic back pain and constitutional symptoms (weight loss, night sweats). An MRI of the thoracic spine shows destruction of the T8 and T9 vertebral bodies, with preservation of the T8/T9 disc space. There is a large, well-defined, bilateral paraspinal abscess.

Question: This pattern is most characteristic of:

(A) Pyogenic Spondylodiscitis (B) Tuberculous Spondylitis (Pott’s Disease) (C) Metastatic Disease (D) Lymphoma (E) Paget’s Disease

Correct Answer: (B) Tuberculous Spondylitis (Pott’s Disease).

Explanation:

  • Why (B) is correct: This is the classic presentation of Pott’s disease. Unlike pyogenic infection, TB spreads sub-ligamentously (under the anterior longitudinal ligament), destroying multiple vertebral bodies while sparing the disc space (because TB lacks the proteolytic enzymes to destroy the disc). This leads to large, “cold” paraspinal abscesses.
  • Why (A) is wrong: Pyogenic infection’s primary target is the disc, which would be destroyed early.
  • Why (C) is wrong: Metastases also spare the disc but do not typically form large, fluid-filled paraspinal abscesses.
  • Why (D) is wrong: Lymphoma is a “great mimicker” and can have a large soft-tissue mass, but TB is the classic cause of this specific “disc-sparing” pattern with a cold abscess.
  • Why (E) is wrong: Paget’s disease is a bone remodelling disorder, not an infection.

Key Points: Tuberculous Spondylitis (Pott’s Disease)

  • Hallmark: Disc space preservation until late-stage.
  • Spread: Sub-ligamentous spread, involving multiple vertebral bodies.
  • Abscess: Forms large, well-defined “cold” paraspinal abscesses.
  • Deformity: Leads to severe kyphosis (gibbus deformity).

Question 9: Inflammatory (Ankylosing Spondylitis)

Stem: A 34-year-old man with known HLA-B27 positivity presents with 10 years of inflammatory back pain and stiffness. A radiograph of the lumbar spine shows squaring of the vertebral bodies, ossification of the outer annulus fibrosus (syndesmophytes), and fusion of the facet joints, creating a “bamboo spine” appearance.

Question: What is the most likely diagnosis?

(A) Ankylosing Spondylitis (AS) (B) Diffuse Idiopathic Skeletal Hyperostosis (DISH) (C) Rheumatoid Arthritis (D) Psoriatic Arthritis (E) Paget’s Disease

Correct Answer: (A) Ankylosing Spondylitis (AS).

Explanation:

  • Why (A) is correct: This is the textbook description of AS, a seronegative spondyloarthropathy. It starts at the sacroiliac joints (causing fusion) and ascends. Key features are: vertebral body “squaring” (from erosions at the corners), and thin, marginal syndesmophytes (ossification of the annulus) that bridge the disc space, leading to the “bamboo spine.”
  • Why (B) is wrong: DISH (Forestier’s disease) also causes fusion but in older patients. It is characterized by flowing, thick, “dripping wax” osteophytes (ossification of the anterior longitudinal ligament), and importantly, the disc spaces and SI joints are preserved.
  • Why (C) is wrong: Rheumatoid arthritis affects the cervical spine (C1-C2 pannus, subluxation) and spares the thoracolumbar spine.
  • Why (D) is wrong: Psoriatic arthritis causes bulky, non-marginal osteophytes, not the thin syndesmophytes of AS.

Key Points: Ankylosing Spondylitis (AS)

  • Pathology: Seronegative (RF-) spondyloarthropathy, HLA-B27 positive.
  • Starts: Sacroiliitis (erosion, sclerosis, fusion) is the hallmark.
  • Spine Findings:
    • “Squaring” of vertebral bodies.
    • Thin, marginal, symmetric syndesmophytes.
    • Facet joint fusion.
    • “Bamboo Spine” (end-stage fusion).
  • Complication: “Chalk stick” fractures (unstable fractures through the fused spine from minor trauma).

Question 10: Tumour (Spinal Metastases)

Stem: A 70-year-old man with a known history of prostate cancer presents with new-onset, severe lumbar back pain. A CT scan reveals multiple, focal, nodular lesions in the L3 and L5 vertebral bodies, which are markedly dense and sclerotic.

Question: This appearance is most typical of what type of metastasis?

(A) Osteoblastic (B) Osteolytic (C) Mixed (D) Lymphomatous (E) Myelomatous

Correct Answer: (A) Osteoblastic.

Explanation:

  • Why (A) is correct: Prostate cancer is the classic primary tumour that causes osteoblastic (sclerotic), or bone-forming, metastases. These appear as dense, “ivory” white lesions on CT and X-ray.
  • Why (B) is wrong: Osteolytic (bone-destroying) metastases are lytic/dark and are classic for lung, renal, and thyroid cancer.
  • Why (C) is wrong: Mixed lytic/blastic metastases are classic for breast cancer.
  • Why (D) is wrong: Lymphoma can be lytic, sclerotic, or mixed, but “blastic” mets in a man with prostate cancer are specific.
  • Why (E) is wrong: Multiple myeloma causes purely lytic, “punched-out” lesions.

Key Points: Metastatic Spine Lesions

  • Hallmark: Destruction of the pedicle (“winking owl” sign on AP X-ray).
  • Disc Space: Spares the disc space (key differentiator from infection).
  • Blastic (Sclerotic): Prostate, Breast (can be), Carcinoid.
  • Lytic (Lucent): Lung, Renal, Thyroid, Breast (most common).
  • Myeloma: Lytic, “punched-out,” but not a “metastasis” (it’s a primary haematological malignancy).

Question 11: Tumour (Multiple Myeloma)

Stem: A 65-year-old man presents with bone pain, renal failure, and anaemia. An MRI of the spine reveals diffuse, abnormal low T1 signal throughout the bone marrow. A CT scan confirms multiple, small, “punched-out” lytic lesions with no sclerotic rim.

Question: What is the most likely diagnosis?

(A) Lytic Metastases (B) Multiple Myeloma (C) Sclerotic Metastases (D) Lymphoma (E) Paget’s Disease

Correct Answer: (B) Multiple Myeloma.

Explanation:

  • Why (B) is correct: This is the classic presentation. Myeloma is a plasma cell malignancy that replaces the normal fatty (T1-bright) marrow, causing diffuse low T1 signal. On CT/X-ray, this manifests as multiple, discrete, “punched-out” lytic lesions with no reactive sclerosis. The clinical CRAB criteria (HyperCalcemia, Renal failure, Anaemia, Bone lesions) fit perfectly.
  • Why (A) is wrong: Lytic metastases are also lytic, but they are typically more irregular, variable in size, and often destroy the pedicles (which myeloma can spare).
  • Why (C) is wrong: These lesions are lytic, not sclerotic.
  • Why (D) is wrong: Lymphoma also infiltrates the marrow (low T1), but the “punched-out” lytic lesions are the classic sign of myeloma.
  • Why (E) is wrong: Paget’s disease is a mixed lytic/sclerotic process that expands the bone.

Key Points: Multiple Myeloma

  • Pathology: Malignancy of plasma cells.
  • Clinical: CRAB criteria.
  • Imaging:
    • Diffuse marrow infiltration (replaces T1-bright fat with T1-dark cells).
    • Multiple “punched-out” lytic lesions (no sclerotic rim).
    • “Cold” on bone scan (no osteoblastic reaction).

Question 12: Tumour (Schwannoma)

Stem: A 48-year-old woman has an incidental finding on a chest CT. An MRI of the thoracic spine is performed, which shows a 2 cm, avidly enhancing, ovoid mass in the intradural-extramedullary compartment at T6-T7. The mass is seen exiting and widening the adjacent neural foramen.

Question: What is the most likely diagnosis?

(A) Schwannoma (B) Ependymoma (C) Astrocytoma (D) Metastasis (E) Meningioma

Correct Answer: (A) Schwannoma.

Explanation:

  • Why (A) is correct: This is the classic “dumbbell” tumour. Schwannomas (and neurofibromas) are nerve sheath tumours. They are the most common intradural-extramedullary mass in the spine. Their hallmark is their tendency to grow through the neural foramen, causing smooth, scalloped widening.
  • Why (B) & (C) are wrong: Ependymomas and astrocytomas are intramedullary tumours (they expand the spinal cord itself).
  • Why (D) is wrong: A “drop” metastasis could be in this compartment, but it would not widen the foramen.
  • Why (E) is wrong: A meningioma is the second most common intradural-extramedullary mass. It is typically a broad-based (“dural tail”) mass that does not exit the foramen.

Key Points: Spinal Tumour Compartments

  • Intradural-Extramedullary (Inside dura, outside cord):
    1. Schwannoma/Neurofibroma: Most common. Causes neural foramen widening (“dumbbell”).
    2. Meningioma: Second most common. Broad dural base, calcifies, does not widen foramen.
  • Intramedullary (Inside cord):
    1. Ependymoma: Most common in adults. Central, haemorrhagic.
    2. Astrocytoma: Most common in children. Eccentric, ill-defined.

Question 13: Tumour (Ependymoma)

Stem: A 40-year-old man presents with progressive lower limb weakness and sensory changes. An MRI of the thoracic spine shows a 3 cm, well-defined, centrally located intramedullary mass that expands the spinal cord at T10. The mass is avidly enhancing and has haemorrhagic “caps” (T2-dark haemosiderin) at its superior and inferior poles.

Question: What is the most likely diagnosis?

(A) Astrocytoma (B) Ependymoma (C) Schwannoma (D) Transverse Myelitis (E) Metastasis

Correct Answer: (B) Ependymoma.

Explanation:

  • Why (B) is correct: This is the classic description of an ependymoma. It is the most common intramedullary tumour in adults. It is typically central (arising from the ependymal cells of the central canal), well-defined, and associated with haemorrhage, leading to the “haemosiderin cap” sign, which is highly specific.
  • Why (A) is wrong: An astrocytoma is the other main intramedullary tumour, but it is typically eccentric, ill-defined, and does not have haemorrhagic caps.
  • Why (C) is wrong: A schwannoma is extramedullary (outside the cord).
  • Why (D) is wrong: Transverse myelitis is an inflammatory process that causes diffuse cord T2 signal and enhancement, but it is not a discrete, haemorrhagic mass.
  • Why (E) is wrong: An intramedullary metastasis is rare and would not have this appearance.

Key Points: Intramedullary Tumours

  • Ependymoma:
    • Most common in adults.
    • Central within the cord.
    • Haemorrhagic: “Haemosiderin cap” sign.
    • Myxopapillary Ependymoma is a specific type in the conus/filum.
  • Astrocytoma:
    • Most common in children.
    • Eccentric, ill-defined, infiltrative.
    • Tends to be longer-segment.

Question 14: Congenital (Tethered Cord)

Stem: A 22-year-old woman presents with new-onset back pain and bladder dysfunction. An MRI of the lumbar spine reveals that the conus medullaris (the tip of the spinal cord) is located at the L3/L4 disc level. The filum terminale is also noted to be thickened (>2 mm).

Question: What is the diagnosis?

(A) Tethered Spinal Cord (B) Spinal Dural AV Fistula (C) Syringomyelia (D) Diastematomyelia (E) Normal Variant

Correct Answer: (A) Tethered Spinal Cord.

Explanation:

  • Why (A) is correct: In a normal adult, the conus medullaris should terminate at or above the L1/L2 disc space. A conus terminating below L2/L3 is, by definition, a low-lying or tethered cord. This causes traction on the cord, leading to neurological symptoms. A thickened filum terminale is a common cause.
  • Why (B) is wrong: A dural AV fistula would show flow voids and cord oedema, not a low-lying conus.
  • Why (C) is wrong: A syringomyelia (or syrinx) is a fluid-filled cyst within the cord. While it can be associated with a tethered cord, it is not the primary diagnosis.
  • Why (D) is wrong: Diastematomyelia is a “split cord” (a sagittal cleft), which is a different anomaly.
  • Why (E) is wrong: This is definitively abnormal.

Key Points: Tethered Spinal Cord

  • Definition: The conus medullaris terminates at or below the L2/L3 disc space in an adult.
  • Causes: Often due to a thickened filum terminale (>2 mm), lipoma, or post-surgical scarring.
  • Symptoms: Back/leg pain, bladder/bowel dysfunction, lower limb weakness.
  • Associations: Often seen with other spinal dysraphisms (e.g., spina bifida, lipomyelomeningocele).

Question 15: Vascular (Spinal Dural AV Fistula)

Stem: A 65-year-old man presents with progressive bilateral lower limb weakness and sensory loss over 6 months. A sagittal T2-weighted MRI of the spine shows diffuse, pencil-like T2 high signal within the central spinal cord extending over multiple levels. Prominent, serpiginous flow voids are seen on the dorsal surface of the cord.

Question: What is the most likely diagnosis?

(A) Transverse Myelitis (B) Multiple Sclerosis (C) Spinal Dural Arteriovenous Fistula (SDAVF) (D) Intramedullary Ependymoma (E) Acute Cord Infarct

Correct Answer: (C) Spinal Dural Arteriovenous Fistula (SDAVF).

Explanation:

  • Why (C) is correct: This is the classic presentation. An SDAVF is an abnormal connection that shunts arterial blood into the low-pressure epidural veins. This causes venous congestion and hypertension, leading to chronic hypoxia and oedema of the cord. This appears as diffuse T2 signal and prominent, dilated perimedullary veins (flow voids).
  • Why (A) is wrong: Transverse myelitis is also a diffuse T2 high signal, but it is an inflammatory process and would not have the prominent dorsal flow voids.
  • Why (B) is wrong: MS plaques are typically focal, eccentric, and involve the cervical cord; they do not cause flow voids.
  • Why (D) is wrong: An ependymoma is a focal, enhancing mass, not a diffuse oedema pattern.
  • Why (E) is wrong: An acute cord infarct (e.g., anterior spinal artery) is very rare, has a sudden onset, and shows T2 signal with restricted diffusion in the “owl’s eye” territory, not dorsal flow voids.

Key Points: Spinal Dural AV Fistula (SDAVF)

  • Pathology: Abnormal shunt (artery -> epidural vein).
  • Consequence: Venous congestion of the spinal cord (congestive myelopathy).
  • MRI Findings:
    1. T2 high signal in the cord, often central/conus (due to oedema).
    2. Serpiginous flow voids on the dorsal surface (dilated veins).
    3. Post-contrast enhancement of the pial surface and veins.
  • Treatment: A treatable cause of myelopathy (via embolization or surgery).

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