To evaluate the significance of diffusion weighted imaging (DWI) for the diagnosis of pyogenic ventriculitis.

In this retrospective study, 9 patients with pyogenic ventricultis underwent a set of imaging sequences that included DWI, T1-and T2-weighted imaging, FLAIR and enhanced T1 weighted imaging. DWI consisted of an axial single shot spin echo EPI pulse sequence with b values of 0 and 1000 sec/mm². We evaluated the presence and signal intensity of ventricular debris, hydrocephalus, periventricular signal abnormality, and ependymal enhancement. The apparent diffusion coffiecient values of ventricular debris and cortical gray matter were calculated from the ADC map.

In all patients, ventricular debris was hyperintense on the DWIs. A periventricular hyperintense signal was present in all cases on FLAIR and T2WI. Ependymal enhancement was detected in eight (89%) of 9 cases. A hydrocephalus was observed in 6 (67%) of 9 cases. The mean ADC value of ventricular debris was 0.735 ± 0.117 (10_-3 mm²/sec). These ADC values were significantly lower than those for cortical gray matter (1.052 ± 0.149 (10_-3 mm²/sec)).

Ventricular debris was most conspicuous finding of ventriculitis on DWI. Areas of intraventricular hyperintensity on DWI corresponded to the decreased ADC values.