Neuroradiology (1982) 23 : 95-99 Neuroradinlogg © Springer-Verlag 1982 Changes of Cerebral Density in Dialyzed Patients* P. Dettori 1, G. La Greca 2, S. Biasioli 2, S. Chiaramonte 2, A. Fabris 2, M. Feriani 2, V. Pinna 1, E. Pisani 2and C. Ronco 2 lInstitute of Neuroradiology and ZDepartment of Nephrology and Hemodialysis, St. Bortolo Hospital, Vicenza, Italy Summary. CT studies were made on 38 patients re- ceiving different dialytic treatment, 10 patients with chronic renal failure not yet dialyzed, and 15 healthy subjects. No morphological modifications were ob- served. On the contrary, significant changes of densi- ty were demonstrated after a dialysis session in the population treated intermittently. In these patients the density values were similar to those registered in the controls 1-6 h after a dialysis session. End stage renal failure and CAPD patients always had normal density values. Therefore cerebral density changes are caused only by the intermittent dialytic treatment. Key words: CT scan - Renal failure - Dialysis - Cere- bral densitometry In order to elucidate the pathophysiological mechanism of acute and chronic dialysis encephalop- athy, we have examined a large population on RTD with cerebral CT. The first approach was carried out on a few patients to determine whether any morpho- logical or densitometrical alterations could be dis- cerned after dialysis. These early studies disclosed a decrease of cerebral density after dialysis, which was initially mistaken by us to be postdialytic cerebral edema [3]. This explanation appeared to agree with the ob- servation of Arieff et al. on experimental DDS in dogs [4]. The preliminary results induced us to study this phenomenon on a wider uremic population, both dia- lyzed and nondialyzed, and on a group of healthy controls [4-5]. Introduction Several neurological disorders have been frequently observed in patients undergoing regular dialysis treat- ment (RTD) [1]. Dialysis disequilibrium syndrome (DDS), characterized by postdialytic headache, nau- sea, muscle cramps, irritability, agitation, delirium, dulled senses and convulsions, is the picture most fre- quently described. Furthermore, dementia, Wer- nicke's encephalopathy, and subdural hematomas occur in a higher percentage in a dialyzed population. All these neurological manifestations, commonly known as "dialysis encephalopathy", have been studied only by clinical and EEG investigations or in dogs, using experimental models evaluating the clini- cal and pathological pattern [2]. * This paper was presented at the 10th Congress of the European Society of Neuroradiology, Milan, September 1981. Material and Methods The study was carried out on 63 subjects (35 female, 28 male), aged 6-71:15 healthy voluntary subjects and 48 with end stage renal failure. Among these 48, 10 were on conservative treatment (mean plasma creatinine of about 10 mg/100 ml) and 38 were on RTD. Table 1 shows the patient population and dialytic schedule. CT examinations were made several times on the same subject in relation to the dialytic treatment or at fixed hours of the day. Blood samples for technicon SMAC 24, acid-base status, hematometry and osmolality were taken from each subject at the same times as the CT examination. A Siemens Siretom 2000 with an independent diag- nostic console (Evaluskop) was used for the CT ex- aminations. 0028-3940/82/0023/0095/$01.00