Altered Short Posterior Ciliary Artery Hemodynamics on Point-of-Care Doppler Imaging: A Novel Biomarker in Acute Mild Traumatic Brain Injury

Background Mild traumatic brain injury (mTBI) lacks sensitive biomarkers for acute cerebrovascular dysregulation. The short posterior ciliary arteries (SPCA), as part of the cerebral circulation, offer a potential window into this pathophysiology via transorbital sonography. Objective This study aimed to evaluate SPCA hemodynamics using point-of-care Color Doppler Imaging (CDI) as a novel functional biomarker in acute mTBI. Methods In this prospective case-control study, thirty adults with acute, isolated mTBI (GCS 13–15) and thirty matched controls underwent standardized transorbital CDI within 24 hours of injury. Hemodynamic parameters—Peak Systolic Velocity (PSV), End-Diastolic Velocity (EDV), Resistance Index (RI), and Pulsatility Index (PI)—were measured in the ophthalmic, central retinal, and short posterior ciliary arteries. Clinical indices (GCS, IOP, visual acuity) were concurrently assessed. Results The mTBI group demonstrated a distinct hemodynamic signature in the SPCA circulation, characterized by significantly elevated vascular resistance (RI: 0.65 ± 0.08 vs. 0.59 ± 0.06, p = 0.001; PI: 1.11 ± 0.26 vs. 0.95 ± 0.17, p = 0.005) and reduced perfusion (PSV: 14.7 ± 4.1 cm/s vs. 18.7 ± 8.4 cm/s, p = 0.021). Increased central retinal artery resistance was also observed (RI: 0.67 ± 0.07 vs. 0.64 ± 0.07, p = 0.042). Glasgow Coma Scale scores showed a significant inverse correlation with retinal arterial pulsatility (CRA-PI: r = -0.286, p = 0.027), linking hemodynamic alterations to neurological status. Conclusions This study identifies altered SPCA hemodynamics—a high-resistance, low-flow profile—as a novel, functional physiological biomarker for acute mTBI, assessable via rapid bedside CDI. These findings expand the mTBI biomarker paradigm from static molecular indicators to include dynamic cerebrovascular dysregulation. CDI of the retrobulbar circulation offers a unique, accessible tool that, with further validation, holds promise for enhancing diagnostic precision, elucidating patient-specific pathophysiology, and guiding personalized management in mTBI.