Multiple laboratory-based neuromuscular diagnostic techniques are referenced throughout this text. Although typically ordered and interpreted by physicians, knowledge of when these techniques are indicated, what conditions they identify, and basic interpretation techniques are valuable clinical skills. Table 5-1 presents an overview of the techniques discussed in this chapter and their most common uses.
Table 5-1Selected Diagnostic Techniques and Their Use ||Download (.pdf) Table 5-1 Selected Diagnostic Techniques and Their Use
|Technique ||Best Use |
|Radiography || |
Standard: Bone lesions, joint surfaces, and joint spaces
Arthrogram: Capsular tissue tears and articular cartilage lesions
Angiogram: Blood vessels
Myelogram: Pathologies within the spinal canal
|Computed Tomography (CT) || |
Bony or articular cartilage lesions and some soft tissue lesions
Quantify detailed bony lesions (e.g., size and location)
Identify tendinous and ligamentous injuries in varying joint positions
Angiography: Artery and/or vein pathologies, including stenosis, aneurysms, and thrombi (clots)
|Magnetic Resonance Imaging (MRI) || |
Visualize soft tissue structures, especially ligamentous and meniscal injuries
Magnetic resonance arthrography (MRA): Used to image blood vessels
Functional magnetic resonance imaging (fMRI): Assesses metabolic activity associated with brain function
|Nuclear Medicine || |
Bone scan: Identifies increased metabolic activity but may yield false-positive findings, especially in endurance athletes
Positron emission tomography (PET): Creates a three-dimensional image of physiological function in the body
Single photon emission computed tomography (SPECT): Produces three-dimensional images of internal structures
|Ultrasonic Imaging ||Detects joint and soft tissue disorders; used to guide injections |
|Electromyography || |
Evaluates muscle physiology at rest and with activity
Identifies pathology of muscle secondary to nerve supply dysfunction or change in the muscle itself
Used in conjunction with a nerve conduction study
|Nerve Conduction Study ||Assesses function of motor and sensory nerves to detect nerve pathology, including axonal degeneration and neurotmesis |
Radiographs, magnetic resonance images (MRIs), computed tomography (CT), bone scans, and diagnostic ultrasounds are collectively referred to as diagnostic imaging. They are obtained by exposing the body to electromagnetic energy, or in the case of diagnostic ultrasound, acoustical energy, and determining how much of that energy is absorbed by the body, is reflected, or passes through the tissues. Most imaging techniques use a source (generator) that transmits the energy to the body and a collector that captures energy that has not been absorbed or scattered. From this, two- or three-dimensional images are constructed.
To obtain the clearest images of the involved structure(s), the diagnostic energy must strike the body from a specific direction and angle. Energy may pass from the anterior through the posterior tissues (anteroposterior [AP]), posterior to anterior (posteroanterior [PA]) or from a left or right lateral projection. The patient and generator may be aligned so that the energy strikes the body at a right angle, or images may be obtained using an oblique or acute angle (Fig. 5-1).
Patient positioning for common radiographic imaging series. Position for ...