This prospective study examined the efficacy of magnetic resonance imaging (MRI) in visualizing cerebrospinal fluid (CSF) leak in patients with postdural puncture headache (PDPH) and determining the spread of the blood patch in the epidural space and the extent of tamponade on the thecal sac. After obtaining institutional review board approval, five patients with symptomatic PDPH after 3 days of failed conservative treatment were included in this study. MRI using proton density (PD) and T2-weighted imaging was performed on all patients and CSF flow studies were done on one patient. All patients received 20 mL of blood in the epidural space. They remained supine for 45 min, and repeat MRI studies were performed. Extent of the spread of blood in the epidural space was measured. A visual analog scale of 0-10 was used to evaluate the headache. All patients had severe postural headache with nausea/vomiting. Preblood patch MRI showed extrathecal CSF and hemosiderosis indicating the site of dural puncture in four patients. The postprocedure MRI demonstrated the blood patch as a large extradural collection with anterior displacement of the thecal sac, the mean spread being 4.6 intervertebral spaces. The tamponade effect of the blood patch was observed on PD, T2-weighted, and CSF flow images. All patients experienced immediate resolution of their symptoms. This study suggests that using MRI, the site of the CSF leak, the tamponade effect of the blood patch, and its spread in the epidural space can be documented.