Abstract
Background
Traditionally, intracranial pressure is measured by direct ventriculostomy, which
is invasive. Noninvasive measures such as bedside ultrasound and magnetic resonance
imaging have been advocated and utilized recently to assess the intracranial pressure.
The role of this study is to determine the degree of agreement between measurements
of the optic nerve sheath diameter by computed tomography (CT) and magnetic resonance
imaging (MRI).
Materials and Methods
Retrospective chart review of 100 consecutive patients who had both MRI and CT scan
of the head from January 1, 2011, until March 31, 2013, at our center was performed.
A discrepancy of 0.2 mm between the 2 measurements was set as acceptable difference.
The measurements of optic nerve sheath diameter (ONSD) were compared for agreement
between the 2 modalities using the method by Bland and Altman.
Results
A total of 100 patients with both MRI and CT scan of the head were selected. Of these
100 patients, 24 were male and 76 were female. The average age was 63 years. No ONSD
abnormality was detected in any of the patients. The discrepancy in measurements of
the ONSD between CT and MRI in transverse plane was less than the predetermined cut-off
value of 0.2 mm. Within-subject variance was estimated at 0.0058 for both CT and MRI.
Conclusion
Comparable results without significant discrepancy as predetermined by the study groups
were obtained from CT scan. Measurement of ONSD by CT scan can be used to indirectly
asses the intracranial pressure in addition to clinical assessment and other signs
of increased intracranial pressure on CT scan.
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Article Info
Publication History
Published online: September 19, 2013
Accepted:
July 25,
2013
Received in revised form:
July 24,
2013
Received:
June 27,
2013
Identification
Copyright
Published by Elsevier Inc.
