Imaging-pathologic correlation in corticobasal degeneration

The clinical diagnosis of corticobasal degeneration (CBD) is often difficult due to varied clinical manifestations. In 4 patients with neuropathologically confirmed CBD, characteristic imaging findings and correlations with neuropathologic features were evaluated. Furthermore, imaging findings in CBD were compared with neuropathologically confirmed progressive supranuclear palsy (PSP) for a differential diagnosis.

Four patients with neuropathologically confirmed CBD were studied. We evaluated the area of the tegmentum in the midsagittal plane, subcortical white matter (SCWM) abnormality, asymmetric cerebral atrophy, and signal-intensity abnormality in the subthalamic nuclei on MR imaging and compared them with histopathologic findings. Then, MR imaging findings in CBD were compared with those in 13 patients with PSP.

On MR imaging, 3 patients had asymmetric cerebral atrophy extending to the central sulcus. On midsagittal sections, the mean midbrain tegmentum area was 66 mm(2), being markedly smaller than normal, but there was no significant difference between PSP and CBD. All patients had signal-intensity abnormalities of the SCWM, constituting primary degeneration neuropathologically; however, no diffuse signal-intensity abnormality in the SCWM existed in the 13 patients with PSP. In 3 patients, T1-weighted images showed symmetric high signal intensity in the subthalamic nuclei. Neuropathologically, these areas showed characteristic CBD. MR imaging signal-intensity changes also existed in 4 patients with PSP; however, subthalamic nucleus degeneration was more severe in PSP than in CBD.

In cases with midbrain tegmentum atrophy and signal-intensity changes in the subthalamic nuclei, the differential diagnosis distinguishing CBD from PSP based on MR imaging alone was difficult. White matter lesions and asymmetric atrophy can be useful for a differential diagnosis.