Purpose: There is no detailed description of the pituitary bright spot (PBS) at 3T in the literature. This study assesses detection of PBS on axial source images of 3D TOF sequence at 3T, and reports cysts in this location for the first time.
Methods: We retrospectively studied 250 consecutive patients who underwent brain 3T MRI with high resolution 3D TOF angiogram and thin axial T2-weighted sequences. On the axial source images of the 3F TOF, we assessed the presence, location and shape of the PBS. A cyst was diagnosed within the PBS in cases with central sharply defined low-TOF signal intensity surrounded by a rim of hyperintense signal. High T2 signal intensity corresponding precisely with the low T1 signal was also necessary for the diagnosis of such cysts. Evolution of these cysts was assessed on follow-up MRI.
Results: PBS was depicted in 83% of patients. Prevalence was significantly higher in women than in men (89% vs 70%, P<0.01). Patients with PBS were significantly younger than those without (mean age 54.1 years vs 59.4 years, P<0.05). A cyst within the PBS was depicted in six patients (2.9%). Mean size was 1.9 mm. These cysts were asymptomatic and remained stable during follow-up.
Conclusions: Axial source images of 3D TOF angiogram can be used to assess the posterior pituitary lobe as the PBS was detected in 83% of our cohort. When cysts are seen within, they may be considered incidental findings that remained stable at follow-up.
Keywords: 3D TOF MR angiography; 3T MR imaging; Cyst; Posterior pituitary lobe.
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