private void FilterDicomDirTreeView()
        {
            foreach (TreeNode node1 in this.dicomDirView.Nodes)
            {
                foreach (TreeNode node2 in patientNode.Nodes)
                {
                    foreach (TreeNode node3 in studyNode.Nodes)
                    {
                        if (!(node3.Text == this.modalityConstraint))
                            node3.Remove();
                    }
                }
            }
        }