functional programming – In Scala, converting CSV into map using first line values as keys and columns values as arrays

I have this format data in CSV :

A,B,C,D
1,2,3,4
5,6,7,8
9,10,11,12

And I need to convert it to map of below format, using lambda expression (no loops)

HashMap<String,mutable.ArrayBuffer(Double)> = new HashMap<>()
("A"->{1,5,9}, "B"->{2,6,10}, "C"->{3,7,11}, "D"->{4,8,12})

Thanks!