An intraspinal fluid collection (ISFC) can be observed on spinal MRI in cases of intracranial hypotension syndrome (IHS). The goal of this study was to analyze the possible persistence of ISFC after therapy and its correlation to clinical disease activity and secondary complications. Twenty patients in our database of 57 patients, who were treated for IHS between 2009 and 2015, fulfilled the inclusion criteria of (a) diagnosed and treated IHS as well as (b) an ISFC in MRI imaging. Ten of these participated in our study. We performed follow-up visits, which included a history, a clinical examination, and a spinal MRI. A MRI-confirmed ISFC was seen in six patients, five of which had symptoms attributable to chronic IHS. There were two cases of superficial siderosis. One patient had a persisting ISFC and was free of symptoms. Four patients did not have an ISFC and were free of symptoms (Fisher's exact test; p < 0.048). There is statistically significant correlation between the persistence of an ISFC after IHS treatment and ongoing clinical symptoms. Resolved symptoms seem to correlate with absorbed extradural ISFC and hypothetically closed leakage site. ISFC as confirmed by MRI proofs to be a reliable follow-up marker for disease activity in chronic IHS that is possibly even superior to clinical examination.