The value of Doppler study of central retinal artery in diagnosis of increased ICP

Abstract

Background
Early diagnosis of increased intracranial pressure (ICP) is vital in neurocritical care due to its strong association with poor outcomes. While invasive monitoring remains the gold standard, non-invasive tools such as optic nerve sheath diameter (ONSD) measurement and central retinal artery (CRA) Doppler ultrasonography have emerged as promising alternatives.


Aim
This study aimed to assess the diagnostic utility of CRA Doppler ultrasonography, specifically the resistive index (RI), in detecting elevated ICP in critically ill patients.


Patients and methods

We consecutively enrolled 66 patients with acute brain injury. Patients were categorized into two groups: those with (group 1,
n
 = 22) and without (group 2,
n
 = 44) elevated intracranial pressure (ICP). The median binocular central retinal artery Doppler indices including resistive index (RI) were compared between the groups. Further analysis was performed to assess baseline and follow-up at 72 h (“control time”) post-treatment changes in ultrasonographic Doppler parameters of CRA RI within the group with raised ICP. A subgroup of 14 patients who underwent invasive ICP monitoring via external ventricular drain (EVD) was analyzed to compare CRA resistive index (RI) values with simultaneously recorded EVD measurements.



Results

The group with raised ICP exhibited significantly higher CRA RI (mean 0.79 vs. 0.64,
p
 < 0.001), reduced PSV and EDV, and larger ONSD (0.63 cm vs. 0.48 cm,
p
 < 0.001) than controls. CRA RI positively correlated with ONSD, midline shift, Marshall score and EVD values, and negatively with Glasgow Coma Scale (all
p
 < 0.05). A binocular CRA RI cut-off > 0.72 yielded 71.6% sensitivity and 88.63% specificity for detecting increased ICP (AUC = 0.911,
p
 < 0.001). CRA Doppler changes reflected treatment response over three days. CRA RI remained significantly associated with ICP after adjusting for mean arterial pressure.



Conclusion
CRA Doppler ultrasonography is a valuable non-invasive adjunct for diagnosing and monitoring increased ICP, particularly when combined with ONSD measurements.