Imaging description

CSF leaks in the spine are most commonly seen following iatrogenic or post-traumatic arachnoid and dural tears. However, spontaneous CSF leaks are increasingly identified as a cause of spontaneous intracranial hypotension (SIH).

The dural tear can result in formation of a pseudomeningocele or fistula at the site of traumatic or iatrogenic injury (spinal surgery, lumbar puncture). On MRI, focal disruption of the dural lining and the contour of the thecal sac can be identified (Figs. 105.1, 105.2), and, in case of large leaks, obvious collections of CSF may be present outside the dura (Fig. 105.3).

The localization of the precise site of CSF leak presents significant challenges in patients with SIH. Conventional CT myelography (CTM) is often very useful in demonstrating the site of leakage, and is considered the modality of choice. However, it may fail to demonstrate very small leaks and may not precisely localize the site in the presence of fast CSF leaks [1,2]. MR myelography with intrathecal gadolinium has been shown to be complementary when no demonstrable leak has been shown on CTM (Fig. 105.2). While its use remains off-label, several studies have shown safety of low-dose intrathecal gadolinium [1].