diff --git a/sahi/models/mmdet.py b/sahi/models/mmdet.py
index c64ea87c7..b4b363d3c 100644
--- a/sahi/models/mmdet.py
+++ b/sahi/models/mmdet.py
@@ -190,7 +190,9 @@ def has_mask(self):
         """
         Returns if model output contains segmentation mask
         """
-        has_mask = self.model.model.with_mask
+        # has_mask = self.model.model.with_mask
+        train_pipeline = self.model.cfg["train_dataloader"]["dataset"]["pipeline"]
+        has_mask = any(isinstance(item, dict) and any("mask" in key for key in item.keys()) for item in train_pipeline)
         return has_mask
 
     @property