Diagnostic Accuracy of Crescent Sign by Ultrasound in Identifying Increased Intracranial Pressure

Increased intracranial pressure (ICP) is a well-known cause of morbidity and mortality in the emergency department. There are many point-of-care ultrasound methods of identifying increased ICP like optic nerve sheath diameter (ONSD), crescent sign, and optic disc elevation. We studied the diagnostic accuracy of the crescent sign in identifying increased ICP.

We conducted a prospective observational study on 135 patients with clinical features of raised ICP between October 2021 and April 2023 at a tertiary care center in India. After examining the patients and recording their demographic details, we performed a point of care ultrasound on the eye to observe for crescent sign. This was followed by a CT scan of the head to look for radiological features of raised ICP. The values were recorded and analyzed using STATA.

We recruited a total of 135 participants for the study, 86 males and 49 females. Crescent sign had a sensitivity and specificity of 54% (46, 65) and 100% (95, 100), respectively, with positive and negative predictive values of 100% (90, 100) and 70% (60, 78), respectively, with a diagnostic accuracy of 78% (70, 84) at p-value <.001.

Crescent sign by ultrasound may be a useful marker for identifying raised ICP in ED patients; however, additional studies are needed to further evaluate sensitivity in users of varying training backgrounds.