New CT measurements to assess decompression after hemicraniectomy: A two-center reliability study

Objectives: To test the reliability of three simplified measurements made after decompressive hemicraniectomy (DHC) for malignant hemispheric infarction on computed tomography (CT) scan. Patients and methods: We defined new simple methods to measure the thickness of the soft tissues overlying the craniectomy defect and the extent of infarction beyond the anterior and posterior craniectomy edges on post-DHC CT. Multiple raters independently made the three new CT measurements in 49 patients from two institutions. The Intraclass Correlation Coefficient (ICC) compared the raters for interrater agreements (reliability). Results: Between two raters at Augusta University Medical Center, each measuring 21 CT scans, the ICC coefficient point estimates were good to excellent (0.83 – 0.92). Among four raters at University of Virginia Medical Center, with three raters measuring each of 28 CT scans, the ICC coefficient point estimates were good to excellent (0.87 – 0.95). Conclusions: The proposed simple methods to obtain three additional CT measurements after DHC in malignant hemispheric infarction have good to excellent reliability in two independent patient samples. The clinical usefulness of these measurements should be investigated.