Guess what this does.
ls $i/*/*|grep DTI|awk -F ':' '{print $1}'1. show everything in all folders to the third level ls $i/*/*
2. show only folder or files which have 'DTI' in its name grep DTI
3. cut the sentence with ':' and print the pre ':' part awk -F ':' '{print $i}'
Think about it. And forget about it.
Good day.