Diagnostic Testing and Imaging of Pain



Diagnostic Testing and Imaging of Pain


Charan Singh

Edward Gillis



Introduction

In the United States, chronic pain affects more than 100 million adults and accounts for approximately $600 billion annually in medical costs and lost productivity (Martucci & Mackey, 2017). Lower back pain is extremely prevalent, with a mean prevalence of 31% for individuals worldwide and a lifetime prevalence between 11% and 84% (Hoy et al., 2012).

In the United States, approximately 80% will be affected at some point in their lives with chronic lower back pain, accounting for 12% to 15% of healthcare visits (Hoy et al., 2012). Imaging has allowed for increased understanding and management of chronic pain, particularly lower back pain. Diagnostic imaging is used to identify the source of pain and/or pathology that could compromise neurologic functioning.

Common imaging studies include:



  • ▶ Plain radiographs


  • ▶ CT/CT myelogram


  • ▶ CT/MR diskography


  • ▶ Bone scan/positron emission tomography (PET)


  • ▶ MRI

Common indications of imaging studies in chronic pain:



  • ▶ Low back and joint pain


  • ▶ Osteoarthritis


  • ▶ Malignancy


  • ▶ Sequela of trauma


  • ▶ Neuropathy/myelopathy


  • ▶ Image-guided interventions such as epidural steroid injections, vertebroplasty/kyphoplasty.


Chronic spine pain is generally secondary to degenerative changes, with osteophyte formation, disk and facet degeneration resulting in narrowing of the central canal and impingement on exiting nerve roots.



▶ KEY POINT

Imaging of uncomplicated back pain is generally reserved for severe or progressively worsening symptoms and starts with plain diagnostic radiographs.


Plain Radiographs/CT

The imaging of uncomplicated chronic pain generally begins with radiographs (Figure 4-1). Presence of osteophytes, spondylolisthesis, dynamic instability, and disk space reduction usually correlates with underlying spinal/neural foramina stenosis. The oblique “Scottie dog” views (Figure 4-2) help determine spondylolysis (pars defects), facet arthropathy, and neural foramina compromise. If there is concern for fracture, superior bony anatomy can be achieved with a noncontrast CT examination.


Magnetic Resonance Imaging

MRI is widely used as a standard method for evaluating spine abnormalities and disease. MRI is ordered with contrast (gadolinium) to improve the clarity of soft tissue images, particularly inflammation, tumors, blood vessels, and, for some organs, blood supply. In general, the decision to include contrast is based on the differential diagnosis and medical condition of the patient, with recommendations provided in Table 4-1.






Figure 4-1. Lateral views of (A) the cervical and (B) lumbar spine in neutral position. Cervical spine with severe degenerative spondylosis. Lumbar spine with severe degenerative spondylosis, which results in 2 mm retrolisthesis of L2 on L3. Note the chronic compression fracture of L1.







Figure 4-2. Right lateral oblique view of the lumbar spine shows the normal appearance of the “Scottie dog.” The transverse process of L3 represents the nose. The pedicle of L3 forms the eye. The inferior L3 articular facet forms the front leg. The superior articular facet of L3 forms the ear. The pars interarticularis, the lamina between the facets, is the neck. Any abnormality at the neck could represent a pars fracture. The circle represents the approximate location of the neural foramen.








Table 4-1. MRI Contrast versus No Contrast



























































Body Region

Reason for Imaging

MRI with or without Contrast


Brain

Headache/migraine


Mental status change/memory loss


Seizures, stroke, transient ischemic attack, trauma

MRI brain without contrast


Brain

Cranial nerve lesion


Infection


Metastatic disease


Multiple sclerosis


Neurofibromatosis


Pituitary involvement

MRI brain with and without contrast


Spine—cervical, thoracic, and/or lumbar

Neck/back pain


Disk herniation/radiculopathy


Extremity pain/weakness


Compression fracture


Stenosis


Trauma

MRI spine (region) without contrast


Spine—cervical, thoracic, and/or lumbar

Diskitis


Mass/lesion


Osteomyelitis


Postsurgery

MRI spine (region) with and without contrast


Extremity—nonjoint

Fracture/stress fracture


Muscle/tendon tear

MRI (extremity) without contrast


Extremity—nonjoint

Abscess


Cellulitis


Morton’s neuroma


Osteomyelitis


Soft tissue tumor/mass/ulcer

MRI (extremity) with and without contrast


Extremity—joint

Arthritis


Cartilage tear


Fracture/stress fracture


Internal derangement


Joint pain


Ligament/meniscal/muscle or tendon tear

MRI (joint) without contrast


Extremity—joint

Abscess


Cellulitis


Osteomyelitis


Tumor/mass/ulcer

MRI (joint) with and without contrast


Pelvis

Pelvic pain


Muscle/tendon tear


Sacroiliac joints


Pelvic pain


Adenomyosis/endometriomas


Uterine anomalies

MRI pelvis without contrast


Pelvis

Abscess/ulcer


Osteomyelitis


Adnexal mass


Endometrial/ovarian cancer


Known fibroids/ovarian cysts

MRI pelvis with and without contrast


Abdomen

Pancreas, gallbladder, liver, ducts

Magnetic resonance cholangiopancreatography without contrast


Abdomen

Kidneys, liver


Mass/infection

MRI abdomen with and without contrast


Brachial plexus

Brachial plexus neuropathy

MRI chest without contrast



For the patient with spinal pain, MRI without contrast is indicated in presurgical planning if the patient fails conservative management. If there is a contraindication to MRI, a CT myelogram (Table 4-2) may be obtained. MRI with contrast is indicated in postsurgical patients with ongoing pain/radiculopathy to differentiate residual disk pathology versus scarring.









Table 4-2. Commonly Affected Nerve Roots and Associated Sensorimotor Deficits











































Nerve Root

Pain/Numbness

Motor Weakness


C5

Lateral upper arm

Elbow flexion


C6

Lateral forearm and 1st-2nd fingers

Wrist extension


C7

Palm and 3rd finger

Elbow extension


C8

Medial forearm and 4th-5th fingers

Finger flexion


L2

Anterior and medial thigh

Hip flexion and adduction


L3

Anterior thigh and knee

Knee extension and hip flexion and adduction


L4

Anterior and medial calf

Hip extension, flexion, adduction


L5

Lateral leg and medial foot (arch)

Foot dorsiflexion and toe flexion and extension


S1

Posterior thigh and calf, heel and lateral foot

Foot plantarflexion and toe and knee flexion

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  4. Surgical and Procedural Pain Management

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Apr 16, 2020 | Posted by in NURSING | Comments Off on Diagnostic Testing and Imaging of Pain

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