diff --git a/+toppe/+utils/getk.m b/+toppe/+utils/getk.m
index 234105c..383536c 100644
--- a/+toppe/+utils/getk.m
+++ b/+toppe/+utils/getk.m
@@ -1,20 +1,26 @@
-function [kxo, kxe] = getk(sysGE, readoutFile, nfid)
-% Get kspace sample locations (assumes dwell = 4us)
+function [kxo, kxe] = getk(sysGE, readoutFile, nfid, del)
+% Get kspace sample locations from .mod file
 % 
 % Inputs:
-%  sysGE
+%  sysGE          see toppe.systemspecs()
 %  readoutFile    .mod file name containing ADC window
 %  nfid           number of acquired samples in ADC window
 %
+% Option:
+%  del            offset by this many samples (default: 0)
+%
 % Outputs:
 %  kxo            [1 nfid], odd echo k-space, cycles/cm
 %  kxe            [1 nfid], even echo k-space, cycles/cm
 
+if nargin < 4
+    del = 0.0;
+end
+
 [rf,gx,gy,gz,desc,paramsint16,paramsfloat,hdr] = toppe.readmod(readoutFile);
 kx = sysGE.raster*1e-6*sysGE.gamma*1e-4*cumsum(gx);  % cycles/cm
 kx = kx - kx(end)/2;
 kx = kx((hdr.npre+1):(hdr.npre+nfid));
-del = -0.0;
 kxo = interp1(1:nfid, kx, (1:nfid) - 0.5 - del, 'linear', 'extrap');
 kxe = interp1(1:nfid, kx, (1:nfid) + 0.5 + del, 'linear', 'extrap');
 kxe = fliplr(kxe);