Optic nerve sheath diameter in patients with malignant media infarction
Lochner P1,  Wagenpfeil G1, Faßbender K1, Lesmeister M1, Brigo F2
1Department of Neurology, Saarland University Medical Center, Homburg, Germany; 2Franz Tappeiner Hospital, Merano, Italy; 3University of Verona, Italy

The ultrasound-based evaluation of the optic nerve sheath diameter (ONSD) has been demonstrated to be a useful and noninvasive assessment for detecting raised intracranial pressure (ICP).
An increase in ONSD from the baseline could be associated with an unfavorable neurological outcome. Our aim was to investigate whether increased ONSD at patient admission and its serial evaluation was associated with raised ICP during the first hours and days after MCA infarction. 

Methods:
Patients were were prospectively recruited in the department of neurology at the University Hospital Homburg/Saar from May 2016 until July 2017.  Inclusion criteria were severe hemisphere media infarction with  intracranial  artery occlusion and infarct demarcation in CT follow-up.

Results:

We prospectively recruited 29 patients admitted from May 2016 until  July 2017. Clinical characteristics of included patients are reported in table 2. Patients were divided in media infarction with not increased ICP group ((group 1 [G1], n = 19) G1) and into malignant media infarction group mMCA (group 2 [G2], n = 10). In the presence of at least one clinical and radiological sign of elevated ICP
Details on stroke onset, ONSD, and CT findings in two groups are visible in table 2.
ONSD on admission was larger in patients who developed mMCA (mean 5.99 mm (SD 0.318)) compared to patients with MCA infarction (4.98 mm (0.532); p=0.003), and to control patients (4.57 mm (0.285); p<0.001). ONSD  change over the days are shown in figure 2. 
Scatter plot of ONSD and stroke volume regression analysis revelead a correlation between the largest ONSD and volumetric evaluation of cerebral infarction in the CT scan on day one (r=0.716; p<0.001).
Receiver Operator Curve (ROC) for ONSD for prediction an malignant MCA infarction. The best sensitivity (100%) and specificity (90%) values were achieved for an ONSD of 5.595 mm; (CI: 0.86-1.0; p<0.001).

Conclusions:
The main finding of our study is that ONSD differed significantly between the G1 and G2 groups as early as 12 hours after the onset of stroke. ONSD and clinical finding (NIHSS>17) are predictive for malignant media infarction.

Further studies are needed to clarify whether the repeated ONSD measurements could help to detect the deterioration of patients and need of decompressive hemicranioctomy.

USELFULNESS OF THE OPTIC NERVE SHEATH DIAMETER IN PATIENTS WITH MALIGNANT MEDIA INFARCTION