diff --git a/libsrc/Itk2DicomConverter.cpp b/libsrc/Itk2DicomConverter.cpp
index 83bc8370..9fdb5b5a 100644
--- a/libsrc/Itk2DicomConverter.cpp
+++ b/libsrc/Itk2DicomConverter.cpp
@@ -90,7 +90,7 @@ namespace dcmqi {
 
       ShortImageType::SpacingType labelSpacing = segmentations[0]->GetSpacing();
       ostringstream spacingSStream;
-      spacingSStream << scientific << labelSpacing[0] << "\\" << labelSpacing[1];
+      spacingSStream << scientific << labelSpacing[1] << "\\" << labelSpacing[0];
       CHECK_COND(pixmsr->setPixelSpacing(spacingSStream.str().c_str()));
 
       spacingSStream.clear(); spacingSStream.str("");