With the metadata viewer you can inspect the data in the 2 indexes dfs_assets_master_index and dfs_assets_web_index. Enter an assetId and select the language to lookup. It will fetch all the metadata around an asset and do a compare between master and web. This will tell you if the data is not in sync on the web.
If you know that an asset for some reason has not been synchronized into Sitecore then you can enter the assetId and click the button Sync asset from Digizuite. This will synchronize the asset into Sitecore and update the metadata or create a new item if it does not exist in Sitecore.
sf
sdf
sf
sdf