Impact of arteriovenous malformations in the precentral and postcentral gyri on intracranial volumes.

Objective: Arteriovenous malformations are known as arterial-venous shunts that connect nidus, the nourishing arteries, to draining veins. Although they are not very common in the brain, they are responsible for approximately 2% of all strokes. The volumetric changes in the surrounding brain tissues caused by cerebral arteriovenous malformations have not yet been reported.

Methods: To detect these volumetric changes, MR data were acquired from 38 controls and 25 unoperated patients with arteriovenous malformations in the precentral and postcentral gyrus. MR data were analyzed with vol2Brain, Ceres and HIPS pipelines. The niduses of these patients were resected by transsulcal microsurgical dissection.

Results: A comprehensive volumetric analysis encompassing 135 distinct brain, cerebellar, and hippocampal structures was conducted using the Vol2brain software. Comparison between the patient group and the control group revealed significant volumetric differences. Specifically, the patient group exhibited significantly larger volumes in the nucleus accumbens, fusiform gyrus, middle occipital gyrus, anterior insula, inferior lateral ventricle, and the gray matter of cerebellar lobules VIIIA and VIIIB compared with the control group. Conversely, relative to the control group, the patient group demonstrated significantly smaller volumes in the gray matter of cerebellar lobules IV, I-II, and III, as well as in the hippocampal subfields of CA2-CA3, SR-SL-SM, and the subiculum.

Conclusion: Arteriovenous malformations occurring in the precentral and postcentral gyrus lead to volumetric changes in structures distant from the site of the malformation, including the brain, hippocampus, and even the cerebellum. Therefore, AVMs may influence the volumes of structures located not only within their immediate brain region but also in other parts of the cerebrum and cerebellum. Understanding these volumetric changes can aid in explaining patient symptoms. However, further research is required regarding whether these volumetric changes result from the mass effect of the nidus or stem from another underlying cause.