PowerShell - Import-CSV - How can I keep leading zeros on all decimal numbers being imported

Question

I am trying to perform changes to a existing CSV, such as keeping specific columns (and removing the rest). However when I use Import-CSV, the leading zeros on certain data is being converted from 0.123 to .123 and -0.456 to -.456. This is leading the program that will digest this information to reject it.

My code looks something like this:

Import-CSV $attachment | Select-object 'colum1', 'column2', column3' | Export-CSV $output

I appreciate any help you can provide. Thank you.