dynamic columnDef in ng-Grid

I want to assign ng-grid columns name dynamically after value returned from database, but issue is that it get initialized before data return from ajax, and i am not able to recall gridOption so it showing balnk, so please help me that how can we construct a column name by ajax return value.

$scope.gridOptions =
        {
            data: 'data.Values',
            columnDefs:
            [
                    { field: "ID", displayName: "Record Id" },
                    { field: "Value", displayName: $scope.ColumnName, cellFilter: cellfilterType },                       
        ],

        };

where $scope.ColumnName coming from below line...

 RecordService.getRecords().then(function (data) {  
  $scope.ColumnName=  data.something;
 }  

Thanks

Thanks Max for your help, I have done this with of help columnDef as below:

Step 1:

$scope.colDef = [];

Step 2:

RecordService.getRecords().then(function (data){      
    $scope.colDef=["ColumnName":data.something]    
}

Step 3:

$scope.gridOptions = {   
    data: 'data.UdiValues',  
    columnDefs:'colDef',            
    filterOptions: $scope.filterOptions  
};