We appreciate the query sent by Drs Zeeman and Cunningham in response to our recent paper, which found clear evidence of posterior reversible encephalopathy syndrome in all of the true eclamptic patients we imaged; the 47th patient who had a seizure originally thought to represent eclampsia was later determined to have an underlying seizure disorder.

The work of Dr Zeeman while at Parkland Hospital in Dallas and subsequently back at home at the Erasmus Medical Center in Rotterdam, The Netherlands, is well known. She is correct in her assertion that the application of diffusion weighted (DW) magnetic resonance imaging (MRI) and apparent diffusion coefficient (ADC) mapping can distinguish between the vasogenic and cytotoxic forms of cerebral edema that can occur in the eclamptic patient.

We did not specifically report this information in our paper because we were not able to undertake this extended level of neuroimaging in all our patients because the value of this advanced study was not uniformly applied during the span of time that our retrospective investigation was undertaken.

Based on our work and that of others including Zeeman and those she cited, it is clear that posterior reversible encephalopathy syndrome should be seen on MRI if the pregnant patient has eclampsia; it appears to have diagnostic value in this setting of abnormal pregnancy. Prognostic value is further gained by the addition of DW and ADC MRI. Going forward, we would agree that it would be desirable prospectively to request that MRI with DW and ADC be undertaken in a patient who has experienced a probable eclamptic seizure. As Dr Zeeman points out, this may also be helpful in the evaluation of the patient with preeclampsia associated with severe features that includes neurological symptomatology, prior to the occurrence of an eclamptic seizure.