Fig 2. Patient 10 is a 27-year-old man with a history of drug and alcohol abuse with a necrotic pneumonia and empyema growing Pseudomonas and Klebsiella. He developed altered mentation and an asymmetric neurologic examination with blood pressures ranging between 130/77 and 130/100 mm Hg. A, Axial MR imaging (FLAIR sequence) demonstrates extensive vasogenic edema in the occipital lobes (open arrows) and temporooccipital junction (arrowheads) consistent with PRES. Additional extensive areas of vasogenic edema consistent with PRES judged vasogenic edema grade 4 were present in the frontal and parietal lobes (not shown). B, Vertebral catheter angiogram obtained after development of occipital hemorrhage (5 days after initial toxicity) demonstrates areas of vessel narrowing and dilation along with a string-of-bead appearance and areas of focal spasm in parietal and occipital branches of the PCA. Right common carotid catheter angiogram (not shown) also demonstrated extensive vasospasm in branches of the ACA and MCA. C, MR angiogram obtained 5 days after catheter angiogram (10 days after initial toxicity) demonstrates persistent vessel irregularity in the posterior cerebral branches (arrows) with a pattern nearly identical to the appearance of the catheter angiogram. Follow-up MR imaging demonstrated improvement of the extensive vasogenic edema.