Incidental findings on CT angiography of the head and neck in stroke patients. Evaluation of frequency and detection rate

Objective: A comprehensive CT algorithm in suspected ischemic stroke consists of a native CT scan, CT perfusion imaging of the brain and a CT angiography from the aortic arch to the vertex. Besides core findings of the brain and targeted vessels, various other findings may be identified. We analyzed a large patient sample and estimated the frequency of incidental findings (IFs) and whether these findings were correctly mentioned in the radiological reports. Patients and methods: In the time period between 01/16 and 02/19 the radiological database of one hospital containing 1625 patients admitted for stroke suspicion were retrospectively evaluated. In total 1175 patients with ischemic stroke CTs were included. IFs were classified according to Lumbreras et al. for their clinical relevance. The primary radiological report was used to classify, whether the finding was reported initially or not. Results: Overall, 1988 IFs were identified in 1175 patients (mean 1.7 findings per patient). The most frequent finding were thyroid incidentalomas with n = 461 (23.2 % of all findings), followed by signs of mucosal swelling and/or opacification of the nasal sinus (n = 391, 19.7 %). Regarding clinical relevance, 181 findings were of major relevance (9.1 % of all findings), 902 were of moderate relevance (45.4 %) and 905 were of minor relevance (45.5 %). Overall, 772 findings (38.8 %) were not reported and 1216 (61.2 %) were sufficiently reported by the radiologist. Conclusion: The present study corroborates that incidental findings are frequent in patients undergoing ischemic stroke CT, which are about half of moderate and major relevance. About 40 % of these findings were not mentioned in the primary radiology report, including findings of high clinical relevance. The radiologist should be aware of these findings.