diff --git a/nibabel/nicom/ascconv.py b/nibabel/nicom/ascconv.py
index 8ec72fb3e..6d7243603 100644
--- a/nibabel/nicom/ascconv.py
+++ b/nibabel/nicom/ascconv.py
@@ -10,7 +10,7 @@
 
 ASCCONV_RE = re.compile(
     r'### ASCCONV BEGIN((?:\s*[^=\s]+=[^=\s]+)*) ###\n(.*?)\n### ASCCONV END ###',
-    flags=re.M | re.S,
+    flags=re.MULTILINE | re.DOTALL,
 )