Not exactly the article I was expecting when I pulled it, but mildly interesting nonetheless. The real applicability of this article is towards those folks who say the LP for SAH is outdated, and we should just proceed with CTA to identify the culprit aneurysm.
As opponents say, many aneurysms identified by CTA are asymptomatic and unrelated to the acute headache in the Emergency Department, and, without the LP, you don’t know their clinical relevance. This study lets them also say that CTA doesn’t even necessarily perform well enough at this task to warrant use – it will miss 5% of aneurysms and overcall 3.8%.
However, it must be said, this meta-analysis uses data from a number of old studies that have older CT scanners that were very poor at detecting <4mm aneurysms. Once you get to 16 and 64 row CT, your sensitivity is closer to 98-99% – and then you have to fall back to the asymptomatic/clinical relevance argument.
“Diagnosing cerebral aneurysms by computed tomographic angiography: meta-analysis”
http://www.ncbi.nlm.nih.gov/pubmed/21391230