The threshold of optic nerve sheath diameter by ocular ultrasonography for the detection of increased intracranial pressure in Korean adult patients with brain lesions

The threshold of optic nerve sheath diameter by ocular ultrasonography for the detection of increased intracranial pressure in Korean adult patients with brain lesions Jin pyeong Jeon, Sang chul Lee, Hannah Lee, Ho geol Ryu Hallym University College of Medicine, Republic of Korea Seoul National University College of Medicine, Republic of Korea Background/Purpose: Previous studies have shown that optic nerve sheath diameter (ONSD) over 5 mm using an ocular ultrasonography (US) is useful for the detection of increased intracranial pressure (IICP) in awhite population-based cohort. However, cut-off point value, which optimally stratifies IICP, has not been studied in Korean population. This study was started to identify the cut-off point value of the ONSD for the detection of IICP in adult patients. Methods: This prospective analysis was done for suspected IICP patients suffering from traumatic brain injury, tumor, or hemorrhage in 3 participating institutions from April 2013 to April 2015. The measurements of ONSD were done by a qualified neurosurgeon and an anesthesiologist using a 13-MHz liner probe. The interpretation of the CT and MRI were done by 2 neurosurgeons. A receiver operating characteristic curvewas constructed to determine theONSD cut-off point. Results: A total of 78 patients who suspected IICP were enrolled. Their mean age was 48.2 ± 13.2 years, and 41 (52.36%) were female. Among them, 56 patients showed IICP according to MRI or CT. The mean ONSD for patients with IICP or without IICP were 5.91 ± 0.31 and 5.22 ± 0.28 mm, respectively. The ONSD cut-off point for identifying IICP was 5.5 mm with a sensitivity of 94.34% (95% CI, 84.3-98.8) and a specificity of 86.67% (95% CI, 59.5-98.3). Conclusions: The cut-off point of ONSD by ocular US in Korea is 5.5 mm, which is lower than that in a white population. Accordingly, ethnic difference should be taken into account when using ONSD for the detection of IICP.