What test should I order for someone with suspected hemiparesis (unilateral weakness)?

From the Guidelines

For someone with suspected hemiparesis, a CT scan is the most appropriate initial imaging test.

Reasons for this choice

• According to the American Heart Association/American Stroke Association guidelines 1, brain imaging is a required component of the emergency assessment of patients with suspected stroke, and CT is the most practical initial brain imaging test for most cases.
• The guidelines also state that CT findings, including the presence of ischemic changes, are not predictors of responses to treatment with rtPA when administered within the 3-hour treatment window.
• While MRI is also an option, CT is generally more readily available and quicker, making it a more practical choice in an emergency setting.
• The American College of Radiology Appropriateness Criteria do not specifically address hemiparesis, but they do provide guidance on imaging for other neurological conditions, such as cranial neuropathy 1.
• It's worth noting that the evidence provided does not support the use of specific motor assessments, such as the Fugl-Meyer Motor Assessment or the Action Research Arm Test, as a substitute for imaging in the diagnosis of hemiparesis 1.

Key points to consider

• The choice of imaging test may depend on the specific clinical scenario and the availability of resources at the institution.
• Vascular imaging may be useful in certain cases, such as when endovascular recanalization therapies are being considered.
• The American Heart Association/American Stroke Association guidelines emphasize the importance of prompt and accurate diagnosis in the management of suspected stroke.

From the Research

Diagnostic Tests for Hemiparesis

To diagnose hemiparesis, the following tests can be considered:

• Computed Tomography (CT) scan of the head to demonstrate areas of ischemia 2
• Point-of-care-ultrasound (POCUS) to identify potential embolic sources, such as a left atrial mass 2
• Non-contrast head CT scan, electrocardiogram, transthoracic echocardiogram, and bedside cardiac telemetry to rule out cardiac causes 3
• Evaluation of upper extremity dexterity using tests such as the Finger Individual Movement Test, Hand Pronation and Supination Test, and Finger Tapping Test 4
• Bedside tests such as the arm drop test, the Babinski thigh-trunk test, Hoover tests, the Sonoo abductor test, and various dynamometer tests to assess functional weakness 5

Considerations for Diagnostic Tests

When ordering diagnostic tests for suspected hemiparesis, consider the following:

• Patient demographics, such as age, to evaluate the likelihood of embolic sources 2
• Presence of other symptoms, such as sensory deficits or dysarthria, to guide the selection of diagnostic tests 6
• The need for urgent evaluation and treatment, such as in cases of suspected stroke or cardiac causes 3, 2