-bilateral ureteric obstruction(long white arrow).

-fibrous band of fibrosis.

Reference:BiblioMed Textbook-Computed Body Tomography

band of fibrous tissue encasing aorta

Reference:BiblioMed Textbook-Computed Body Tomography

could be idiopathic or due to:

-ruptured aortic aneurysm.

-malignant etiology(cause moderate enhancement).

Reference:BiblioMed Textbook-Computed Body Tomography