Arterial Spin Labeling Was Useful for Evaluating the Treatment Response of a Transverse-Sigmoid Sinus Dural Arteriovenous Fistula: A Case Report

Abstract

Objective: We report the case of a patient in whom arterial spin labeling (ASL) was useful for assessing the effects of treatment for a transverse-sigmoid sinus dural arteriovenous fistula (TSS-dAVF).

Case presentation: The patient was a 65-year-old man. Cerebral angiography demonstrated an aggressive dAVF involving the TSS, superior sagittal sinus (SSS), and the sinus confluence, with severe cortical and deep venous reflux. We performed multiple transarterial and transvenous embolizations for the TSS and sinus confluence lesion. The shunt disappeared almost completely after embolization. A high signal intensity that had been apparent in the SSS and straight sinus (StS) on ASL imaging before embolization disappeared after embolization. ASL imaging 3 months after embolization revealed slightly a high signal intensity in the StS, which was considered to be due to recurrence of the lesion. Moreover, recurrence of the confluence and TSS-dAVF was observed on cerebral angiography 6 months after embolization. As additional embolization was considered difficult, radiation therapy was recommended, but the patient refused; therefore, follow-up was performed. As ASL imaging findings were consistent with cerebral angiography findings, careful examination and monitoring of changes on ASL imaging were subsequently performed.

Conclusion: Follow-up using ASL imaging is useful to assess the effects of treatment performed for a dAVF.

Keywords: arterial spin labeling; dural arteriovenous fistula.

Fig. 1. MRI imaging before treatment. (A) DWI shows a hyperintense area in the subcortical white matter of the bilateral occipital lobes. (B) T₂*WI shows marked vessel dilatation with suspected cortical veins. (C) TOF-MRA source imaging shows nodular and curvilinear hyperintensities in the right SS and TS. (D) ASL imaging shows a venous ASL signal in the bilateral TS and the left SS due to shunting. (E) ASL imaging shows a high signal intensity in the SSS due to shunting. ASL: arterial spin labeling; DWI: diffusion-weighted imaging; SS: sigmoid sinus; SSS: superior sagittal sinus; T₂*WI: T₂*-weighted imaging; TOF: time-of-flight; TS: transverse sinus

Fig. 2. Cerebral angiography imaging before treatment. (A) Right external carotid angiography (anteroposterior view) shows a TSS-dAVF supplied by the right OA and MMA. (B) Right external carotid angiography (lateral view) shows a high-flow arteriovenous shunt to the sinus, and retrograde sinus drainage to the superior sagittal and StSs. (C) Left external carotid angiography (anteroposterior view) shows a TSS-dAVF supplied by the left OA and MMA. (D) Right internal carotid angiography (lateral view) shows cortical vein dilatation in the cerebrum and cerebellum with a PPP. MMA: middle meningeal artery; OA: occipital artery; PPP: pseudophlebitic pattern; StS: straight sinus; TSS-dAVF: transverse–sigmoid sinus dural arteriovenous fistula

Fig. 3. Cerebral angiography imaging immediately after embolization. (A) Right external carotid angiography after embolization (anteroposterior view) confirmed the disappearance of the shunt supplied by the right OA and MMA disappeared. (B) Right external carotid angiography after embolization (lateral view) confirmed the disappearance of the retrograde sinus drainage to the superior sagittal and StSs. MMA: middle meningeal artery; OA: occipital artery; StS: straight sinus

Fig. 4. MRI imaging after embolization: 5 days after embolization and 3 months after embolization. (A) TOF-MRA source imaging 5 days after embolization shows the slight hyperintensities in the sinus confluence. (B) ASL imaging 5 days after embolization shows a high signal intensity in the sinus confluence. (C) TOF-MRA source imaging 3 months after embolization shows the increased hyperintensities in the sinus confluence. (D) ASL imaging 3 months after embolization shows a high signal intensity in the sinus confluence and left TS. (E) DWI 3 months after embolization shows the disappearance of the hyperintense area in the bilateral occipital lobes. (F) T₂*WI 3 months after embolization shows the disappearance of the vessel dilatation with suspected cortical veins. ASL: arterial spin labeling; DWI: diffusion-weighted imaging; T₂*WI: T₂*-weighted imaging; TOF: time-of-flight; TS: transverse sinus

Fig. 5. Cerebral angiography imaging 6 months after embolization. (A) Right external carotid angiography 6 months after embolization (anteroposterior view) shows the recurrence of the confluence and TSS-dAVF supplied by the right OA and PAA. (B) Right external carotid angiography 6 months after embolization (lateral view) shows the presence of retrograde drainage to the StS. OA: occipital artery; PAA: posterior auricular artery; TSS-dAVF: transverse–sigmoid sinus dural arteriovenous fistula; StS: straight sinus

Fig. 6. ASL color map and T2 fusion imaging, TOF-MRA source imaging of treatment progress. (A) ASL color map and T2 fusion imaging before embolization show a high signal intensity in the SSS and StS due to shunting. (B) ASL color map and T2 fusion imaging 5 days after embolization show the disappearance of the high signal intensity in the SSS and StS. (C) ASL color map and T2 fusion imaging 3 months after embolization show the recurrence of slightly high signal intensity in the StS. (D) ASL color map and T2 fusion imaging a year after embolization show the recurrence of markedly high signal intensity in the StS. (E) TOF-MRA source imaging before embolization shows hyperintensities in the SSS and StS due to shunting. (F) TOF-MRA source imaging 5 days after embolization shows the slight hyperintensities in the StS. (G) TOF-MRA source imaging 3 months after embolization shows the disappearance of hyperintensities in the StS. (H) TOF-MRA source imaging a year after embolization shows the recurrence of marked hyperintensities in the StS. ASL: arterial spin labeling; SSS: superior sagittal sinus; StS: straight sinus; TOF: time-of-flight