Neuronal Dysfunction And Hemodynamic Disturbance Due To Venous Congestion In Dural Arteriovenous Fistula Revealed By I-123-iomazenil Single-photon Emission Computed Tomography

Objective: Retrograde leptomeningeal venous drainage (RLVD) of a dural arteriovenous fistula (dAVF) is related to neurological morbidity and unfavorable outcomes. However, the direct damage to cortical neurons by dAVF with RLVD has not been elucidated. 123 I-iomazenil ( 123 I-IMZ) single-photon emission computed tomography (SPECT) can reveal cerebral blood flow and cortical neuronal damage in early and late images, respectively. This study aimed to assess the relationship association between cerebral venous congestive encephalopathy caused by dAVF using 123 I-IMZ SPECT. Methods: Based on the pre- and post-treatment magnetic resonance imaging findings, patients were divided into three groups: normal, edema, and infarction groups. Radioactivities in the early and late images of 123 I-IMZ SPECT were investigated using the affected-to-contralateral side asymmetry ratio (ACR). Results: None of the patients in the normal group showed any symptoms related to venous congestion. In contrast, all the patients in the edema and infarction groups developed neurological symptoms. The ACR in early images in the edema group was significantly lower than that in the normal group and significantly higher than that in the infarction group. The ACR in the late images of the infarction group was significantly lower than those of the normal and edema groups. After treatment, the neurological signs disappeared in the edema group, but only partial improvement was observed in the infarction group. The ACR in early images significantly improved after treatment in the edema group; however, that in late images did not change in any groups. Conclusions: 123 I-IMZ SPECT is useful for evaluating hemodynamic disturbances and neuronal damage in dAVFs. The reduction in early images was correlated with the severity of venous congestive encephalopathy, and the significant reduction in late images is a reliable indicator of irreversible venous infarction caused by RLVD.