Evaluation and Diagnosis of Neuronal Integrity in Diffuse Axonal injury : A 123I-Iomazenil SPECT and MRI Study

• Published in: Higher Brain Function Research Vol. 44; no. 1; pp. 11 - 18
• Main Authors: Mori, Etsuro, Kato, Hiroki
• Format: Journal Article
• Language: English; Japanese
• Published: Japan Society for Higher Brain Function 31.03.2024
• Subjects: diffuse axonal injury; iomazenil; SPECT; traumatic brain injury
• ISSN: 1348-4818; 1880-6554
• DOI: 10.2496/hbfr.44.11

Objective assessment of the neuronal abnormalities in cases of traumatic brain injury (TBI) with diffuse axonal injury (DAI) is crucial to understanding the underlying pathology, as well as from the point of view of facilitating socioeconomic support for these patients. Neuronal integrity can be evaluated by benzodiazepine binding using 123I-iomazenil (IMZ) SPECT. We aimed to investigate the extent of neuronal damage in cases of TBI with DAI using 123I-IMZ SPECT and MRI. The findings in 31 patients with TBI without any major focal brain lesions were compared with those of 25 age-matched normal controls. Subjects underwent 123I-IMZ SPECT and MRI, and also assessment by cognitive function tests. The partial volume effect of 123I-IMZ SPECT was corrected using MRI. Regional benzodiazepine binding and brain atrophy in TBI were assessed based on the volume of interest and voxel-based analysis. In the patients with TBI, decreased binding of 123I-IMZ was detected in the medial frontal/orbitofrontal cortex, posterior cingulate gyrus, cuneus, precuneus, and superior region of the cerebellum. The decreased 123I-IMZ binding in the cuneus and precuneus was associated with cognitive decline after the injury. In the patients with TBI, brain atrophy was detected in the frontal lobe, anterior temporal and parietal cortex, corpus callosum, and posterior part of the cerebellum. ROC analysis of 123I-IMZ SPECT for the detection of neuronal injury showed a high diagnostic ability of 123I-IMZ binding for TBI in the cingulate gyrus, medial regions of the frontal, parietal, and occipital lobes, and superior region of the cerebellum. Evaluation of the neuronal integrity by 123I-IMZ SPECT provides important information for the diagnosis and pathological interpretation in cases of TBI with DAI.