#!/usr/bin/perl -w
use File::Copy;
use File::Path;

use strict;
use warnings;

....
/* 
$filename, $pat_name, $study_date, $study_time, $series_num are defined
*/
....

my ($new_filename, $dir_path);

#create new pathname
$dir_path = "$pat_name/$study_date-$study_time/$series_num";
   
#create new filename
$new_filename="$pat_name-$study_date-$study_time-$series_num-$image_num.dcm";

eval { mkpath($dir_path) }; 
if ($@) {
   print "Couldn't create $dir_path: $@";
}

$new_filename = "$dir_path/$new_filename";


rename($filename,$new_filename) or die( "could not rename $filename to $new_filename: $!\n" );


##</code><code>##

system("mv",$filename,$new_filename) or die("could not rename $filename to $new_filename: $!\n");

##</code><code>##

move($filename,$new_filename) or die("could not rename $filename to $new_filename: $!\n");

##</code><code>##

could not rename 1.2.840.113619.2.55.1.1762883246.3061.1000220985.209/1.2.840.113619.2.55.1.1762883246.3061.1000220985.210/1.2.840.113619.2.55.1.1762883246.3061.1000220985.212.dcm to S000109A33/20010911-125602/1/S000109A33-20010911-125602-1-2.dcm: Is a directory

##</code><code>##

if( ! -e $dir_path) { system("mkdir","-p",$dir_path); }

##</code><code>##

system("mkdir","-p",$dir_path) or warn("could not make dir $dir_path: $!\n");