COMPARISON OF CT SCAN BRAIN AND ULTRASOUND-GUIDED OPTIC NERVE SHEATH DIAMETER (US-ONSD) FOR NON-INVASIVE DETECTION OF CEREBRAL EDEMA IN STROKE PATIENTS

Abstract

Objective: To determine the accuracy of ultrasound-based optic nerve sheath diameter (US-ONSD) for determining raised intracranial pressure (ICP) in stroke patients. Methods: In this validation study, we included 100 patients who were admitted with stroke in the ICU of CMH, Quetta, with suspicion of raised ICP. Initially, all patients underwent a CT scan to determine the presence, size, and location of the stroke and measure intracranial pressure (ICP). After CT scan evaluation bedside ultrasound was performed by single operator in all patients for measuring ONSD. Results: The patients had an average age of 48.7 ± 11.9 years. The APACHE IV score averaged 55.8 ± 14.5. The sensitivity of US-ONSD in relation to CT scan was 92.1%, while specificity was 90.9%. The positive predictive value (PPV) was notably high at 98.8%, suggesting that a positive test result is highly indicative of actual elevated ICP, while the negative predictive value (NPV) was 58.8%. Conclusion: The diagnostic accuracy of US-ONSD measurement in predicting raised ICP, when compared to CT findings, was good, yielding an optimal cutoff of 5.5 mm.