Radiology Alliance for Health Services ResearchValidation of a New Reference Standard for the Diagnosis of Vasospasm
Section snippets
Study Population
We performed a retrospective study on consecutive patients admitted to our institution, with the diagnosis of A-SAH between January 2002 and May 2009. Inclusion criterion for the study was an admission diagnosis of A-SAH as determined by chart review. Institutional review board approval was obtained.
Study Design
All A-SAH patients were applied to this new multistage hierarchical reference standard in a stepwise manner. An advantage of using this reference standard is that no patients were excluded and all
Patients
A total of 137 patients were identified for inclusion in this study. Importantly, no patients were excluded from the study. There were 85 patients who had DSA performed during their hospital course and were included in Phase I of the study. However, all 137 patients were included in Phase II. Clinical and demographic data are presented in Table 1.
In Phase I (n = 85), using DSA at the primary level as the gold standard, vasospasm was diagnosed in 57 (67%) patients and no vasospasm in 28 (33%)
Discussion
Often times, a perfect gold standard does not exist in clinical or research practice. The accuracy of a new diagnostic test determined by using an imperfect gold standard introduces biases and inconsistencies in the results. In clinical practice, gold standards are rarer than one might think (11). For example, colposcopy-guided biopsy of the cervix has been considered the gold standard for disease detection of cervical neoplasia for decades; however, the sensitivity is only 60%, leading to
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This publication was made possible by Grant Number 5K23NS058387-02 from the National Institute of Neurological Disorders and Stroke (NINDS), a component of the National Institutes of Health (NIH). Its contents are solely the responsibility of the authors and do not necessarily represent the official view of NINDS or NIH.