diff --git a/tests/lbpm_uCT_pp.cpp b/tests/lbpm_uCT_pp.cpp
index 302ad4fc..ae180ee7 100644
--- a/tests/lbpm_uCT_pp.cpp
+++ b/tests/lbpm_uCT_pp.cpp
@@ -615,7 +615,7 @@ int main(int argc, char **argv)
 	}
 
     // array containing a distance mask
-    Array<float> MASK(Nx[i]+2,Ny[i]+2,Nz[i]+2);
+    Array<float> MASK(Nx[0]+2,Ny[0]+2,Nz[0]+2);
     
     // Create the level data
     std::vector<Array<char>>  ID(N_levels);