Spinal Imaging and Diagnostic Tests

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Spinal Imaging and Diagnostic Tests

♦ Imaging Modalities

I. General considerations

A. Spinal imaging modalities (Table 3–1)

1. Plain radiographs

2. Computed tomography

3. Magnetic resonance imaging (MRI)

4. Bone scintigraphy

5. Myelography

6. Angiography

7. Discography

B. A thorough history and physical examination should lead to a preliminary clinical diagnosis that should predicate both the selection and timing of imaging tests.

1. Diagnostic tests should be used to confirm information ascertained during the history and physical examination.

C. Selection of imaging tests should be based on the appreciation of the sensitivity, specificity, and accuracy of various imaging modalities in conjunction with different disease processes.

1. Acute neck or back pain and radiculopathy

a. Natural history is that of improvement with conservative treatment

b. Diagnostic imaging should be delayed until 4 to 6 weeks after the onset of symptoms.

(1) Exceptions to earlier imaging evaluation include

(a) Trauma

(b) Progressive neurological deficit

2. Imaging evaluation alone without clinical correlation is associated with an extremely high false-positive rate.

**Table 3–1** Imaging Modalities
Imaging Modality	Indications/Advantages	Limitations
Plain radiographs	Initial modality for trauma, neoplasm, infection, deformity, and degenerative disorders	Not specific Bone loss >30–40% needed to be detected by plain radiographs
Computed tomography	Axial images with multiplanar and three-dimensional reconstruction capabilities Advantages: bony detail, fractures, differentiate hard/soft discs	Less accurate in demonstrating intrathecal and soft tissue pathology Narrow field of view Radiation exposure
Myelography and computed tomographic myelography	Water-soluble dye mixes with the cerebrospinal fluid and outlines the dural sac Demonstrates an extradural mass by impression in the dye column or root cutoffs and intrathecal lesions by filling defects	Invasive Unable to assess distal to a complete block Computed tomography myelography improves the accuracy of foraminal/lateral recess stenosis and herniated disc lesions. Axial and reconstructed images improve visualization of the lateral recess and foramen
MRI	The procedure of choice for the majority of spinal pathology Using pulsed RF, MRI detects the energy released by a proton during the transition from and excited state to a baseline state Accurate Wide field of view Multiplanar images Noninvasive No radiation exposure	Less bony detail as compared with computed tomography Difficult to interpret in patients with a large deformity Costly Claustrophobic Difficult in obese patients
Bone scintigraphy (technetium99m, gallium-67 citrate, indium-11 White Blood Cell (WBC) scan)	Assess metastatic bone disease Distinguish acute versus old pars interarticularis fractures	Nonspecific
Discography	Provocative test reflects symptomatic changes in the Intervertebral Disc (IVD) Abnormal discogram results in the reproduction of back/neck pain with the same character/distribution Dye extravasates from the confines of the disc space through tears of the annulus fibrosus Indications include persistent nonradicular pain suspicious of discogenic etiology and preoperative evaluation prior to a spinal fusion	Discography is controversial and its use should be selective Risks include infection, radicular pain, headache, iatrogenic disc degeneration, or herniated disc