Background and Purpose-Increasing attention has been paid to associations between cognitive dysfunction and brain microbleeds (MBs). Because all previous studies have investigated patients with neurological disorders, we examined subjects without neurological disorder in order to clarify pathogenic relationships. Methods-A total of 518 consecutive adults without neurological disorder who had undergone health-screening tests of the brain were studied prospectively. Gradient-echo T2*-weighted MRI using a 1.5-T system was used to detect MBs. The Mini-Mental State Examination (MMSE) was administered to determine cognitive functions. MMSE scores Ͻ27 or Ͼ1.5 SDs below the age-related mean were regarded as subnormal. Results-MBs were found in 35 subjects (6.8%). MMSE score Ͻ27 was found in 25 subjects (4.8%), with MMSE score Ͼ1.5 SDs below the age-related mean in 34 subjects (6.6%). Univariate analysis showed presence and number of MBs, short duration of education, and severe white matter hyperintensities as significantly associated with subnormal scores.

Vascular obliteration and a blunt sternum-anterior mediastinum angle were predictive of thymic carcinoma. Pleural effusion and mediastinal fat infiltration were predictive of a poor prognosis.

In this series, the survival of the patients in the CUP subgroup without a specific therapy did not seem worse than that in previous reports. Empirical chemotherapy with platinum-containing regimens may benefit some CUP patients in a subgroup without a specific chemotherapy.