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Relative energy index of microembolic signal can predict malignant microemboli
Youngbin Choi1, Maher Saqqur, Eileen Stewart
1Department of Neurology and Psychiatry, St. Louis University, St. Louis, MO 63110, USA. ybinchoi@gmail.com
Background And Purpose:
Microembolic signals (MES) found on transcranial Doppler range from harmless air bubbles to large, solid, particulate emboli from the heart and large vessels. The presence of MES is not always associated with poor clinical outcome. The purpose of our study was to determine whether the relative energy index of MES measured by power M-mode Doppler can distinguish malignant from benign MES and to identify patients with worse prognosis.
Methods:
We prospectively collected transcranial Doppler emboli monitoring data from patients with symptomatic carotid stenosis presenting with TIA or ischemic stroke. For each patient, we calculated the relative energy index of MES and categorized those >1.0 as malignant MES. We compared the clinical characteristics, number, and volume of diffusion-weighted imaging lesions, and degree of stenosis and plaque characteristics on CT angiogram of patients with malignant and benign MES.
Results:
We enrolled 92 patients, 29 with TIA and 63 with stroke, within 48 hours of symptom onset. Twenty-six patients had a total of 319 MES; of these, 82.4% were benign and were 17.6% malignant. Malignant MES traveled further within intracranial vessels than benign MES. The 9 patients with >1 malignant MES had significantly larger baseline diffusion-weighted imaging lesion volume, had a higher prevalence of intraluminal thrombus on CT angiogram of the neck and plaque ulceration, and were more likely to have a poor clinical outcome (modified Rankin Score > or = 2) than those with benign MES (OR, 6.5; 95% CI, 1.47-28.68). The presence of malignant MES led to the institution of more aggressive secondary prevention measures.
Conclusions:
Power M-mode transcranial Doppler identifies a subgroup of patients with malignant MES. These signals are more frequent in longer arterial trajectory. Patients with malignant MES have larger baseline infarcts, a higher prevalence of intraluminal thrombus or ulcerated plaque in the carotid artery, and worse clinical outcome.
Insights
Power M-mode Doppler can identify malignant microembolic signals (MES) in patients with carotid stenosis. Malignant MES indicate a higher risk of stroke and worse outcomes, prompting aggressive secondary prevention.
Area of Science:
- Neuroscience
- Cardiovascular Medicine
- Medical Imaging
Background:
- Microembolic signals (MES) detected via transcranial Doppler (TCD) vary in origin and clinical significance.
- The presence of MES does not always correlate with adverse clinical outcomes.
Purpose of the Study:
- To evaluate the relative energy index (REI) of MES using power M-mode Doppler to differentiate malignant from benign MES.
- To identify patients with a worse prognosis based on MES characteristics.
Main Methods:
- Prospective collection of TCD emboli monitoring data in patients with symptomatic carotid stenosis and TIA/stroke.
- Calculation of MES REI, categorizing signals >1.0 as malignant.
- Comparison of clinical characteristics, lesion volume (DWI), and CT angiogram findings between malignant and benign MES groups.
Main Results:
- 17.6% of 319 MES were malignant; malignant MES had a longer intracranial trajectory.
- Patients with >1 malignant MES showed larger infarct volumes, more intraluminal thrombus/ulcerated plaque, and poorer outcomes (mRS > or = 2).
- Malignant MES presence led to intensified secondary prevention strategies.
Conclusions:
- Power M-mode TCD effectively identifies patients with malignant MES.
- Malignant MES are associated with longer arterial paths, larger infarcts, carotid plaque instability, and worse clinical prognosis.
- Identification of malignant MES aids in risk stratification and treatment decisions.
