Dilated perivascular spaces in the putamen and pallidum in patients with Parkinson's disease scheduled for pallidotomy: A comparison between MRI findings and clinical symptoms and signs

Forty patients with Parkinson's disease without mental deterioration who we re scheduled for ventroposterolateral (VPL) pallidotomy were randomly selec ted for retrospective stereotactic magnetic resonance image (MRI) analysis. The preoperative MRI study was performed on a 1.0-T MRI machine with a thr ee-dimensional gradient-echo sequence. The MRI analysis was focused on five consecutive 2 mm thick axial slices without gap and parallel to the interc ommissural line, starting from the level of the foramen of Monro and contin uing in a ventral direction. Lacunar cysts of varying sizes (4-424 mm(3)) w ere seen at least in one hemisphere of all patients. The cysts had a clear dominance in posteroventral regions of the lateral-most pallidal regions (G P) and posteroventral regions of the putamen (PUT). No statistical correlat ion was found be-tween the number or volume of the cysts and the sex, age, or duration of illness of the patients. Patients with predominantly left-si ded clinical symptoms had a concentration of the cysts in the left GP, wher eas those with predominantly right-sided symptoms had cysts significantly l arger and more frequent in the right than the left GP. The cysts did not se em to affect the clinical outcome of pallidotomy. The authors think striato pallidal cysts develop from dilated perivascular spaces of the lenticulostr iate vessels in the posteroventral regions of the GP and PUT. They are not pathognomonic for PD, but they may play some role in lateralization of the clinical symptoms in this classically asymmetric condition.