Detecting circRNAs from RNA-seq data

Question

[gudetama2001]

Hello,

I am a beginner in this field and some days ago I thought of detecting circRNAs from the RNA-seq data. I know that circRNA transcripts have somewhat "peculiar" order: "5’ exons were ‘shuffled’ downstream of 3’ exons. Despite the non-canonical ordering, the exons were complete and used the usual splice donor and acceptor sites." (Jeck et al. 2014).

My question is: why do we need an extra tool for the circRNA identification like find_circ? Why can't normal alignment algorithms detect circRNAs, too?

Thank you-