Abstract TP60: Effect of Clinical History in Radiologist Interpretation of Computed Tomography for Acute Stroke

Abstract

Introduction: Computed tomography (CT) is widely used for suspected acute ischemic stroke. Radiologists often interpret these scans with limited information and may benefit from more complete knowledge of the clinical situation. Hypothesis: Providing detailed clinical information improves the interpretation of CTs for acute stroke. Methods: In the prospective Cornell AcutE Stroke Academic Registry (CAESAR), we randomly selected 100 patients who underwent noncontrast head CT within 6 hours of transient ischemic attack (TIA) or minor acute ischemic stroke (National Institutes of Health Stroke Scale score ≤3) and underwent magnetic resonance imaging (MRI) within 6 hours of the CT. Three radiologists each twice evaluated CT studies both with and without accompanying information on the patient’s medical history, neurological deficit, and symptom time course. In random sequence, each study was interpreted by each radiologist in one condition (i.e., with or without detailed accompanying information), and then after a 4-week washout period, the same study was interpreted again by each radiologist in the opposite condition. Using MRI diffusion weighted imaging (DWI) as the reference standard for brain infarction, we classified CT interpretations as correct (true positives or true negatives) or incorrect (false positives or false negatives). McNemar’s test was used to compare the proportion of correct interpretations in the condition with detailed clinical information versus the condition without detailed information. Results: In patients with DWI-defined infarcts, acute ischemia was correctly called on 20% (95% confidence interval [CI], 14-27%) of CTs with detailed history versus 18% (95% CI, 12-25%) without history. In patients without infarcts, the absence of acute ischemia was correctly called on 77% (95% CI, 70-84%) of CTs with history and 77% (95% CI, 69-83%) without history. The proportion of correct interpretations of CTs accompanied by detailed clinical history (49% [95% CI, 43-54%]) did not differ significantly from those without history (47% [95% CI, 42-53%]) ( P = 0.67). Conclusions: Reported findings on head CT for evaluation of suspected acute ischemic stroke were similar regardless of whether detailed clinical history was provided.