[The effect of age and disease on the MR imaging T2 low signal intensity area in the cerebral cortex].
We retrospectively studied magnetic resonance (MR) images of the brain in 139 patients (16 cases of Alzheimer's disease, 8 cases of Parkinson's disease, 53 cases of multiple cerebral infarct, 33 cases of other central nervous diseases, and 29 cases of peripheral neuropathy) between the age of 6 and 85 years old with a mean age of 60.6 +/- 18.5 to examine the appearance of T2 low signal intensity areas (T2CLIA) in the cerebral cortex. Motor, occipital, sensory or other cortices were evaluated with long repetition time/echo time (TR/TE) spin-echo sequences and staged into three grades in the motor cortex: none, partial, and whole; and two grades in the others: none or present. In general, T2CLIA was not seen in any cortex in patients less than 50 years old, then after 50 years old T2CLIA increased with age. Over 70 years of age T2CLIA appeared in 50.9% of patients in the whole motor cortex, 88.7% in either whole or partial motor cortex, 47.2% in the occipital cortex, and 20.8% in the sensory cortex. T2CLIA was not observed in other cortices. The incidence of T2CLIA appearance in the motor cortex was significantly higher in all central nervous diseases than in cases of peripheral neuropathy over 70. T2-CLIA showed a correlation with temporal lobe atrophy and white matter lesions in the motor cortex. In the sensory cortex, T2CLIA correlated with white matter lesions. These results suggest that T2-CLIA may correlate with age or accumulation of nonheme iron in the cortex associated with central nervous diseases.