How to prioritize fusions based on these columns?

Potential_fusions written by tophat-fusion-post writes these 5 columns but I don't what these columns really mean. Can anyone explain? E.g. I don't understand how can "reads" be less than "pe_reads". What is the difference between "pe_reads" and "pe_reads_span". What is reads_ctrd?

What is the priority order of these columns in order for me to identify which fusion to prioritize to be biologically meaningful? ANy help will be greatly appreciated!

reads pe_reads pe_reads_span reads_ctrd reads_left reads_right

5201 4465 588 9 85309 85184

4640 488 3279 5 289783 45

3394 13258 1764 1 36 62

Thanks.