AIM: To test the performance of computed tomography angiography "source images" (CTA-SI) versus unenhanced CT (NCCT) for stroke detection and extent using the Alberta Stroke Programme Early CT Score (ASPECTS), and examine the effect of experience and clinical history. MATERIALS AND METHODS: Studies of 23 consecutive patients presenting within 4.5h were analysed by three reviewers of varying experience. Each reviewer, blinded to clinical information reviewed a random order of NCCT and CTA-SI and documented side of infarct and the ASPECTS. The readings were repeated for CTA-SI with and without clinical information. Performance measures and observer agreement were calculated. Applying an ASPECTS threshold of<or=7, the number of patients misclassified was determined. RESULTS: CTA-SI improved trainee accuracy by 9%, but had little impact on more experienced readers. The accuracy and sensitivity of stroke extent assessment was increased for all readers, but was greatest for the trainee (17% and 12%, respectively). Clinical history contributed little to CTA-SI accuracy. Observer agreement was higher for CTA-SI. NCCT could have resulted in the misclassification of more patients than CTA-SI. CONCLUSION: CTA-SI are an important adjunct in acute stroke assessment, improving stroke extent determination for all readers irrespective of level of experience. In addition less experienced readers may benefit from CTA-SI for detection of presence of strokes. CTA-SI performance appears independent of clinical history. CTA-SI resulted in fewer misclassified patients if an ASPECTS threshold of <or=7 is considered.
AIM: To test the performance of computed tomography angiography "source images" (CTA-SI) versus unenhanced CT (NCCT) for stroke detection and extent using the Alberta Stroke Programme Early CT Score (ASPECTS), and examine the effect of experience and clinical history. MATERIALS AND METHODS: Studies of 23 consecutive patients presenting within 4.5h were analysed by three reviewers of varying experience. Each reviewer, blinded to clinical information reviewed a random order of NCCT and CTA-SI and documented side of infarct and the ASPECTS. The readings were repeated for CTA-SI with and without clinical information. Performance measures and observer agreement were calculated. Applying an ASPECTS threshold of<or=7, the number of patients misclassified was determined. RESULTS: CTA-SI improved trainee accuracy by 9%, but had little impact on more experienced readers. The accuracy and sensitivity of stroke extent assessment was increased for all readers, but was greatest for the trainee (17% and 12%, respectively). Clinical history contributed little to CTA-SI accuracy. Observer agreement was higher for CTA-SI. NCCT could have resulted in the misclassification of more patients than CTA-SI. CONCLUSION: CTA-SI are an important adjunct in acute stroke assessment, improving stroke extent determination for all readers irrespective of level of experience. In addition less experienced readers may benefit from CTA-SI for detection of presence of strokes. CTA-SI performance appears independent of clinical history. CTA-SI resulted in fewer misclassified patients if an ASPECTS threshold of <or=7 is considered.
Authors: Ke Lin; Otto Rapalino; Benjamin Lee; Kinh G Do; Amado R Sussmann; Meng Law; Bidyut K Pramanik Journal: Neuroradiology Date: 2008-09-12 Impact factor: 2.804
Authors: C A Raji; C Lee; O L Lopez; J Tsay; J F Boardman; E D Schwartz; W S Bartynski; H M Hefzy; H M Gach; W Dai; J T Becker Journal: AJNR Am J Neuroradiol Date: 2010-01-14 Impact factor: 3.825