TrueFISP imaging of the pineal gland: more cysts and more abnormalities.

INTRODUCTION: Although pineal cysts are found with a frequency of over one third in autopsy series, prevalences reported in standard magnetic resonance imaging (MRI) studies only range between 0.14% and 4.9%. With the advances in scanner technology and more sensitive high-resolution 3D-sequences, pineal cysts with atypical appearance are more frequently encountered as an incidental finding. In order to help the radiologist and the clinician to correctly interpret these incidental findings and to avoid follow-up MRI or even surgical intervention, we analysed the frequency of typical and atypical pineal cysts using standard MRI-sequences and a high-resolution 3D-trueFISP-sequence (true-Fast-Imaging-with-Steady-State-Precession).

METHODS: In 111 patients undergoing MRI we analysed the prevalence of pineal cysts in relation to gender and age, as well as the frequency of atypical cysts defined by thickened rim, trabeculations, or asymmetric form using three standard MRI-sequences (T1-SE (T1 weighted spin echo), T2-TSE (T2 weighted turbo spin echo), FLAIR (fluid attenuated inversion recovery)) and compared the diagnostic certainty of these standard sequences with the sensitivity of a high-resolution trueFISP MRI sequence.

RESULTS: Using trueFISP pineal cysts were detected more frequently than in the standard sequences (35.1% vs. 9.0% (T1-SE), 4.5% (T2-TSE) and 9.0% (FLAIR)). Diagnostic uncertainty was least frequent in trueFISP. In trueFISP, 41.0% of the detected cysts showed one or more features of atypical cysts (standard sequences: 21.4%). Highest prevalence of cysts was detected in the group of 20-30-year-old patients and decreased with increasing age.

CONCLUSION: High-resolution 3D-sequences like trueFISP increase the detection rate of pineal cysts to levels reported in autoptic series while decreasing the diagnostic uncertainty. Atypically configurated pineal cysts are frequently detected as an incidental finding.