diff --git a/idc_index/index.py b/idc_index/index.py
index 9c7aa1c9..3083dc48 100644
--- a/idc_index/index.py
+++ b/idc_index/index.py
@@ -331,11 +331,11 @@ def get_series_file_URLs(self, seriesInstanceUID):
         # Query to get the S3 URL
         s3url_query = f"""
         SELECT
-          series_aws_url
+        series_aws_url
         FROM
-          index
+        index
         WHERE
-          SeriesInstanceUID='{seriesInstanceUID}'
+        SeriesInstanceUID='{seriesInstanceUID}'
         """
         s3url_query_df = self.sql_query(s3url_query)
         s3_url = s3url_query_df.series_aws_url[0]
@@ -353,7 +353,11 @@ def get_series_file_URLs(self, seriesInstanceUID):
 
         # Parse the output to get the file names
         lines = output.split("\n")
-        file_names = [s3_url + line.split()[-1] for line in lines if line]
+        file_names = [
+            s3_url + line.split()[-1]
+            for line in lines
+            if line and line.split()[-1].endswith(".dcm")
+        ]
 
         return file_names