Purpose:
To investigate the incidence and various imaging features of posterior reversible encephalopathy syndrome (PRES) in pediatric patients following hematopoietic stem cell transplantation (HSCT).
 
Materials and Methods:
This prospective study was carried out between March 2014 and June 2016 on all pediatric patients after HSCT. All patients who developed neurologic symptoms underwent Brain MRI (1.5 T magnet, Avanto, Siemens), which included DWI and SWI sequences. In those with the diagnosis of PRES, a follow-up MRI was conducted within 2 months.  
 
Results:
A total of 254 post-HSCT patients were enrolled (160 males, mean age:7.6±4 years), These patients included 65 individuals with thalassemia, 41 with fanconi anemia, 59 with lymphoma/leukemia and 89 with other miscellaneous disorders. Twenty-three patients (9.1%) were diagnosed with PRES based on clinical findings and MRI results. The incidence of PRES was markedly higher in those with fanconi anemia compared to those with other diseases (p value: 0.004). MRI showed asymmetric edema in 10 patients. The most common imaging pattern was Superior frontal sulcus distribution (34.8%), followed by holo-hemispheric(26.1%), dominant posterior(26.1%) and partial(13%) distributions. Foci of microhemorrhage were noted in five patients. Of these five patients, two died shortly after PRES, while three patients had persistent microhemorhagic foci in follow-up exam with another patient dying later after a second episode of PRES
 
Conclusion:
PRES is highly prevalent in pediatric patients after HSCT, especially in those with underlying fanconi anemia. A large percentage of individuals with PRES have atypical imaging findings. A minority of individuals’ experience Hemorrhagic PRES, which is possibly associated with a worse prognosis.