Our aim was to measure cerebellum Volume (CV), sclerotic plaque numbers (PN), and plaque surface area (SA) in the parietal lobe, and to investigate the relationship between CV and PN or SA in the parietal lobe, and the clinical status of patients with Multiple sclerosis (MS). MRIs we e performed in 14 patients with relapsing-remitting MS (RRMS), 13 patients with secondary progressive MS (SPMS), and 26 healthy control participants. The Cavalieri method was used to measure CV and SA. The cerebellum volume was significantly reduced in MS patients compared to controls (p < 0.01). In all patients, CV was negatively correlated with the duration of the disease, relapse number, and Expanded Disability Status Scale (EDSS) scores (p < 0.01). CV was related to mean PN in both the right and left parietal lobes (p < 0.01) and mean SA (p < 0.05) in RRMS patients; CV was also correlated with mean PN (p : 0.01) and mean SA (p < 0.05) in SPMS patients. The progression index (Pi) values were 2.03 +/- 0.4 in RRMS patients and 0.83 +/- 0.2 in SPMS patients (p = 0.023, t = 2.612) (where Pi = EDSS/time from onset in years), We propose that atrophy begins both in the supratentorial and infratentorial areas simultaneously in the RR stage, and that the Cavalieri method can be used to predict SPMS among patients with RRMS. (C) 2009 Elsevier Ltd. All rights reserved.