diff --git a/oxasl/region_analysis.py b/oxasl/region_analysis.py
index adbf02c..544a38f 100755
--- a/oxasl/region_analysis.py
+++ b/oxasl/region_analysis.py
@@ -553,6 +553,9 @@ def run(wsp):
 
     wsp: Output data workspace
     """
+    if not wsp.structural.struc:
+        return
+
     wsp.log.write("\nRegionwise analysis\n")
 
     if wsp.pvwm is not None: