Extract DICOM Image From RayStation Microsoft SQL Database - sql-server

Question

I was given a backup RayStation database, RS_Patients.bak, and am trying to extract and view the DICOM images that are stored in it. The trouble is two-fold: I don't know which one of the 2,000+ fields (or combinations of fields) refer to the images themselves, and even if I did know where the images were, I don't know how to extract them from the database into .dcm files.
From examining the schema, I found a few fields that are large varbinary fields (BLOBs) and I think they might be the fields I'm looking for. FileStream is enabled for the database and there is an FS directory. I've tried to download those fields into files using the bcp Utility, but that hasn't generated successful DICOMs.
Does anyone have any experience with this sort of database/image structure? Any other suggestions for pulling out and viewing the image? Do you think the image would be made up of a couple of fields instead of just one? There are fields next to what we believe the image field with headers for the DICOM image: in the table callefd ImageStack, next to a field called PixelData, there are fields called PixelSize, SlicePosition, NrPixels, etc.
Also, if you can think of another place to ask this, I would appreciate that too.
Edit per #mcNets suggestion, the bcp command:
DECLARE #Command Varchar(400)
SET #Command = 'bcp "SELECT TOP 1 PixelData FROM RayStationPatientDB.dbo.ImageStack" queryout "C:\Users\Administrator\Documents\test.dcm" -S WIN-123ABC\MSSQLSERVER01 -T -w'
EXEC xp_cmdshell #Command

Answer 1

Generally speaking, you're not going to be able to use SQL Server results to write image data directly. bcp.exe isn't going to help you, either. You need to either use something that understands that the binary string is raw file data, or, because this is a FILESTREAM, use something that will give you the path to the file on the SQL Server. I have limited experience with FILESTREAM, but here's what I would do.
I can't definitively answer which field to use. That will depend on the application. If we assume that the DICOM images are stored in a FILESTREAM, then you can find the available FILESTREAM columns with this:
select t.name TableName
,c.name ColumnName
from sys.tables t
join sys.columns c
on c.object_id = t.object_id
where c.is_filestream = 1
If we also assume that DICOM images are stored as raw image files -- i.e., as a complete binary version of what they would be if they were saved on a PACS disc -- then you can run this to determine the path for each file by the ID:
select TableName_Id
,FileData.PathName()
from TableName.ColumnName
The doc for the PathName() function of FILESTREAM columns is here.
If you instead want to pull the data through SQL Server in a traditional sense, then I would probably use a PowerShell script to do it. This has the advantage of letting you use arbitrary data from the server to name the files. This method also has the advantage that it will work on any binary or varbinary column. As a disadvantage, this method will be slower and uses more disk space, because the server has to read the data, send it to the client, and then the client writes the data to disk:
$SqlQuery = "select Name, FileData from TableName.ColumnName";
$OutputPath = 'C:\OutputPath';
$SqlServer = 'ServerName';
$SqlDatabase = 'DatabaseName';
$SqlConnectionString = 'Data Source={0};Initial Catalog={1};Integrated Security=SSPI' -f $SqlServer, $SqlDatabase;
$SqlCommand = New-Object -TypeName System.Data.SqlClient.SqlCommand;
$SqlCommand.CommandText = $SqlQuery;
$SqlConnection = New-Object -TypeName System.Data.SqlClient.SqlConnection -ArgumentList $SqlConnectionString;
$SqlCommand.Connection = $SqlConnection;
$SqlConnection.Open();
$SqlDataReader = $SqlCommand.ExecuteReader();
while ($SqlDataReader.Read()) {
$OutputFileName = Join-Path -Path $OutputPath -ChildPath "$($SqlDataReader['Name']).dcm"
[System.IO.File]::WriteAllBytes($OutputFileName,$SqlDataReader['FileData']);
}
$SqlConnection.Close();
$SqlConnection.Dispose();
It's also possible to use FILESTREAM functions to return Win32 API handles, but I have never done that.