MRI findings in Parinaud’s syndrome: a closer look at pineal masses

Purpose: The association between MRI findings in patients with pineal lesions and the presence or absence of Parinaud’s syndrome (PS) remains poorly described. We sought to better understand what MRI characteristics of a pineal lesion make PS more likely. Can these features predict prognosis for clinical resolution? Based on the anatomical relationship of the pineal gland and midbrain, we hypothesized that the degree of midbrain injury by a pineal mass as assessed by abutment, displacement, or intrinsic midbrain signal abnormality (IMSA) may predict PS. Methods: We reviewed our institution’s databases to find patients with MRI evidence of an intrinsic lesion of the pineal gland. Seventy-seven patients with intrinsic pineal gland lesions, 26 with PS and 51 without PS (NPS), were identified. Data regarding clinical history were collected, and an experienced neuroradiologist reviewed all MRI studies and recorded mass size, midbrain abutment, displacement by the pineal lesion, and presence or absence of IMSA. Results: IMSA occurred with increased frequency in pineal lesions with PS (85%) when compared with NPS (39.2%) (p = 0.0001). Midbrain abutment, compression, and displacement occurred with similar frequencies in both groups, with no statistically significant difference. Hydrocephalus was present in 80.8% of patients with PS and 84% without PS (p = 0.75). Conclusion: IMSA in a patient with an intrinsic pineal gland mass is associated with PS. Other findings such as hydrocephalus and midbrain displacement are common in patients with pineal masses both with and without PS and do not have any predictive value.