Detection of entorhinal layer II using Tesla magnetic resonance imaging

Abstract The entorhinal cortex lies in the mediotemporal lobe and has major functional, structural, and clinical significance. The entorhinal cortex has a unique cytoarchitecture with large stellate neurons in layer II that form clusters. The entorhinal cortex receives vast sensory association input, and its major output arises from the layer II and III neurons that form the perforant pathway. Clinically, the neurons in layer II are affected with neurofibrillary tangles, one of the two pathological hallmarks of Alzheimer's disease. We describe detection of the entorhinal layer II islands using magnetic resonance imaging. We scanned human autopsied temporal lobe blocks in a 7T human scanner using a solenoid coil. In 70 and 100μm isotropic data, the entorhinal islands were clearly visible throughout the anterior–posterior extent of entorhinal cortex. Layer II islands were prominent in both the magnetic resonance imaging and corresponding histological sections, showing similar size and shape in two types of data. Area borders and island location based on cytoarchitectural features in the mediotemporal lobe were robustly detected using the magnetic resonance images. Our ex vivo results could break ground for high‐resolution in vivo scanning that could ultimately benefit early diagnosis and treatment of neurodegenerative disease. Ann Neurol 2005;57:489–494