diff --git a/oxford_asl.in b/oxford_asl.in
index aa8d6cb..2a09ab2 100755
--- a/oxford_asl.in
+++ b/oxford_asl.in
@@ -402,10 +402,10 @@ Calibration() {
 	usetrans=$tempdir/asl2struct.mat
 
 	if [ ! -z $fasthasrun ]; then
-	    # we have already run FAST so we can pass the PVE for CSF to asl_calib (to save running FAST again)
-	    extraoptions=$extraoptions" --refpve $tempdir/pvcsf_struct"
+        # we have already run FAST so we can pass the PVE to asl_calib (to save running FAST again)
+        extraoptions=$extraoptions" --refpve $tempdir/pv${tissref}_struct"
 	fi
-   
+
 	$asl_calib -c $tempdir/calib -s $usestruc -t $usetrans -o $outdir/calib --bmask $tempdir/mask --osen $outdir/native_space/sensitivity $maincaliboptions $extraoptions 
 
     else