Perfusion computed tomography in a dural arteriovenous fistula presenting with focal signs: vascular congestion as a cause of reversible neurologic dysfunction.

OBJECTIVE

To describe the use of perfusion computed tomography (PCT) in the study of hemodynamic disturbances associated with a case of a cerebral dural arteriovenous fistula (DAVF) with leptomeningeal venous drainage presenting with focal signs.

CLINICAL PRESENTATION

A 79-year-old man presented because of loss of strength in the right arm. On examination, he presented mild right-side hemiparesis. Magnetic resonance imaging showed the presence of a left frontoparietal hyperintense lesion on T2-weighted images. Magnetic resonance angiography and digital substraction angiography (DSA) showed a convexity Borden type III DAVF. The DAVF was embolized with bucrylate, and control DSA showed complete obliteration of the malformation. The patient improved from his clinical presentation and 6 months after treatment was asymptomatic.

TECHNIQUE

Perfusion computed tomography was performed before and after treatment. All imaging studies were performed on a 6-slice spiral computed tomography scanner. Each series studied a 2.4-cm slide of brain at the level of the cerebral convexity where the DAVF was located. Quantitative perfusion data were obtained from significant regions of interest of both hemispheres, and an interhemispheric ratio (IR) was calculated. Pretreatment PCT showed an increase in mean transient time (IR = 2.2) and time to peak (IR = 1.15), with an increase in cerebral blood volume (IR = 1.9) in the left frontal areas related to a similar area in the contralateral hemisphere. Six months after treatment, perfusion maps did not show any interhemispheric difference.

CONCLUSION

Perfusion computed tomography could help to identify the hemodynamic disturbances associated with DAVFs with leptomeningeal venous drainage.