TrueFISP imaging of the pineal gland: More cysts and more abnormalities
Introduction
Pineal cysts are frequently encountered from the fetal period to old age. In autoptic series the prevalence of pineal cysts has been reported to range between 33% and 40% [1], [2], whereas a strong discrepancy was observed in MRI studies reporting significantly lower prevalence of 0.14–4.3% at standard field strengths (1.5 T) [3], [4], [5], [6], [7], [8].
Histologically, most of the cysts are localised in an area of gliosis, but occasionally they are lined by ependymal or parenchymal cells [1], [9]. Since up to 25% of the benign cysts for unknown reasons undergo changes in size [10], the radiological differentiation of benign pineal cysts from cystic neoplasms of the pineal gland as pineocytomas, pinealoblastomas or astrocytomas [11], [12] – which is crucial for the clinical management – can be difficult. Furthermore, it is under discussion, whether pineal cysts depend on gender or age [1], [4], [5], [6], [10], [13], [14], [15], [16].
The goals of our study were to clarify (i) if using a high-resolution trueFISP sequence (true-Fast-Imaging-with-Steady-State-Precession) can close the gap between the prevalence reported in autoptic and older MRI studies and (ii) whether there are age or gender-related differences in the distribution of cysts, as lately discussed. Finally, we assessed the frequency and morphology of typical and atypical pineal cysts in standard and in trueFISP imaging, to help the radiologists and clinicians to better estimate the relevance of randomly detected typical or atypical pineal cysts.
Section snippets
Patients and MRI protocol
111 patients enrolled for cranial MRI were randomly included in this study. Written informed consent was obtained from all patients. Exclusion criteria were artefacts or mass lesions prohibiting the evaluation of the pineal gland in any of the sequences.
MRI was performed using a 1.5 T MR scanner (Siemens Sonata or Siemens Avanto, Siemens, Erlangen, Germany). MR sequences for all patients comprised transversal T1-SE (T1 weighted spin echo, TR/TE 434/11), T2-TSE (T2 weighted turo spin echo, TR/TE
Results
111 patients were enrolled for cranial MRI (47 females, 64 males, age 19–86 years, mean age 58 years). Diagnosis comprised stroke (n = 47), intracranial neoplasm without midline shift (n = 22), inflammatory disease (n = 8), neurodegenerative or metabolic changes (n = 6), epilepsy (n = 5), intracranial aneurysm (n = 2), hydrocephalus (n = 2) and unremarkable intracranial MRI findings (n = 19) with various reasons for enrollment (vertigo (n = 5), cephalgia (n = 3), sinusitis (n = 3), visual disturbance (n = 3) and
Discussion
Cystic pineal neoplasms are rare, while benign pineal cysts are frequently encountered in MRI or autoptic series (about one third of cases [1], [2]). Large pineal cysts can compress the superior colliculi of the quadrigeminal plate or the aqueduct of the midbrain resulting in obstructive hydrocephalus. In these cases symptoms comprise vertigo, headache, visual impairment (diplopia, blurred vision), hemiparesis, vomiting, papilledema, oculomotor nerve paresis and Parinaud syndrome. Cases of
Conclusion
We provide evidence that the use of high-resolution trueFISP imaging increases the sensitivity of MRI to detect pineal cysts: using trueFISP, the prevalence of pineal cysts for the first time reaches frequencies hitherto reported only in autoptic studies. TrueFISP imaging allows a more accurate delineation of the pineal gland including intracystic abnormalities thereby decreasing diagnostic uncertainties in comparison to standard sequences. Using high-resolution MRI cysts with atypical
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