--- a/Core/DicomFormat/DicomInstanceHasher.cpp	Fri Dec 21 13:53:24 2012 +0100
+++ b/Core/DicomFormat/DicomInstanceHasher.cpp	Fri Dec 21 17:18:04 2012 +0100
@@ -36,12 +36,15 @@
 
 namespace Orthanc
 {
-  DicomInstanceHasher::DicomInstanceHasher(const DicomMap& instance)
+  void DicomInstanceHasher::Setup(const std::string& patientId,
+                                  const std::string& studyUid,
+                                  const std::string& seriesUid,
+                                  const std::string& instanceUid)
   {
-    patientId_ = instance.GetValue(DICOM_TAG_PATIENT_ID).AsString();
-    studyUid_ = instance.GetValue(DICOM_TAG_STUDY_INSTANCE_UID).AsString();
-    seriesUid_ = instance.GetValue(DICOM_TAG_SERIES_INSTANCE_UID).AsString();
-    instanceUid_ = instance.GetValue(DICOM_TAG_SOP_INSTANCE_UID).AsString();
+    patientId_ = patientId;
+    studyUid_ = studyUid;
+    seriesUid_ = seriesUid;
+    instanceUid_ = instanceUid;
 
     if (patientId_.size() == 0 ||
         studyUid_.size() == 0 ||
@@ -52,6 +55,14 @@
     }
   }
 
+  DicomInstanceHasher::DicomInstanceHasher(const DicomMap& instance)
+  {
+    Setup(instance.GetValue(DICOM_TAG_PATIENT_ID).AsString(),
+          instance.GetValue(DICOM_TAG_STUDY_INSTANCE_UID).AsString(),
+          instance.GetValue(DICOM_TAG_SERIES_INSTANCE_UID).AsString(),
+          instance.GetValue(DICOM_TAG_SOP_INSTANCE_UID).AsString());
+  }
+
   const std::string& DicomInstanceHasher::HashPatient()
   {
     if (patientHash_.size() == 0)