Posterior Reversible Encephalopathy Syndrome (PRES) is a neurotoxic condition characterized by a distinctive pattern of brain vasogenic edema, often seen on CT or MRI. It is associated with various conditions such as preeclampsia/eclampsia, allogeneic bone marrow transplantation, organ transplantation, autoimmune diseases, and high-dose chemotherapy. The syndrome typically presents with symmetric hemispheric edema, predominantly in the parietal and occipital regions, and can involve other areas like the frontal lobes, cerebellum, and brainstem. MRI, particularly diffusion-weighted imaging, is crucial in identifying vasogenic edema, which usually reverses completely. Clinical features include headache, vision changes, paresis, and altered mental status, with hypertension being common in many cases. The exact mechanism of PRES remains controversial, with hypotheses involving both hyperperfusion and hypoperfusion. Imaging patterns vary, and the condition can present in different forms, including holohemispheric, superior frontal sulcal, and primary parietal-occipital. PRES is also associated with various other conditions, including infections, sepsis, and shock. Histopathological findings often show vasogenic edema, astrocytic changes, and evidence of endothelial injury. Advanced imaging techniques such as MRA and perfusion MRI help in assessing cerebral blood flow and vascular changes. The management of PRES involves addressing the underlying condition and monitoring for neurological deterioration. The syndrome can recur, particularly in cases of severe hypertension or after allogeneic bone marrow transplantation. Understanding the imaging and clinical features of PRES is essential for timely diagnosis and appropriate management.Posterior Reversible Encephalopathy Syndrome (PRES) is a neurotoxic condition characterized by a distinctive pattern of brain vasogenic edema, often seen on CT or MRI. It is associated with various conditions such as preeclampsia/eclampsia, allogeneic bone marrow transplantation, organ transplantation, autoimmune diseases, and high-dose chemotherapy. The syndrome typically presents with symmetric hemispheric edema, predominantly in the parietal and occipital regions, and can involve other areas like the frontal lobes, cerebellum, and brainstem. MRI, particularly diffusion-weighted imaging, is crucial in identifying vasogenic edema, which usually reverses completely. Clinical features include headache, vision changes, paresis, and altered mental status, with hypertension being common in many cases. The exact mechanism of PRES remains controversial, with hypotheses involving both hyperperfusion and hypoperfusion. Imaging patterns vary, and the condition can present in different forms, including holohemispheric, superior frontal sulcal, and primary parietal-occipital. PRES is also associated with various other conditions, including infections, sepsis, and shock. Histopathological findings often show vasogenic edema, astrocytic changes, and evidence of endothelial injury. Advanced imaging techniques such as MRA and perfusion MRI help in assessing cerebral blood flow and vascular changes. The management of PRES involves addressing the underlying condition and monitoring for neurological deterioration. The syndrome can recur, particularly in cases of severe hypertension or after allogeneic bone marrow transplantation. Understanding the imaging and clinical features of PRES is essential for timely diagnosis and appropriate management.