PMC9534565_01
Magnetic resonance and positron emission tomography images.
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A: T2-weighted image. A high signal was observed in the left cerebellar hemisphere. B: One month after the first T2-weighted image. A high signal was expanded over time. C: Gd-enhanced T1-weighted image of the same period as B. Contrast effects are observed on the surface of the left cerebellar hemisphere. D: Apparent diffusion coefficient map showed a high signal, suggesting the finding of vasogenic cerebral edema. E: Fluorodeoxyglucose (FDG) positron emission tomography (PET) image. Mildly increased FDG uptake on the outside of the left cerebellar hemisphere, consistent with lesions imaged with gadolinium-enhanced magnetic resonance imaging (Gd-MRI). Region of interest was measured at the blue circles. F: Methionine-PET image. Increased methionine uptake on the outside of the left cerebellar hemisphere, consistent with lesions imaged with Gd-MRI. Region of interest (ROI) was measured at the blue circles.
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Although there was no worsening of symptoms, MRI T2-weighted image showed a high signal inside the left cerebellar hemisphere, which increased progressively over 1 month (Fig. 1A, B). The outside of the hyperintensity region of MRI T2-weighted image was mottled and strongly enhanced, especially on the surface of the cerebellum (Fig. 1C). The apparent diffusion coefficient map image at this time showed an elevated signal, which suggested vasogenic cerebral edema (Fig. 1D). At first, FDG-PET showed a slight increase in FDG uptake (tumor to normal [T:N] ratio: 1.22) in the region enhanced by Gd-MRI (Fig. 1E). Methionine-PET also showed increased methionine uptake (T:N ratio: 1.88) in the region enhanced by Gd-MRI (Fig. 1F).
Preoperative clinical images of magnetic resonance angiography and digital subtraction angiography.
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A: An axial image of time-of-flight magnetic resonance angiography. The arrow indicates the mastoid branch, a feeder branching from the occipital artery and running over the dura mater. B and C: Frontal and lateral view of left-sided occipital angiography. D and E: Close-up image of super-selective angiography of the mastoid branch of the occipital artery. Black arrows indicate the shunt point.
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These findings suggested Cognard type 3, nonsinus-type StS-DAVF (Fig. 2B-E).
Postoperative images of digital subtraction angiography, positron emission tomography, and T2-weighted image.
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A and B: Frontal and lateral view of left-sided occipital angiography after Onyx transarterial embolization; the shunt flow disappeared completely. C: Six months after surgery, the high preoperative uptake found in methionine-positron emission tomography had disappeared. D: T2-weighted image. The abnormal hyperintense area in the left cerebellum had also been extensively improved.
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Onyx 18 (Medtronic, Minneapolis, MN, USA). A micro guidewire Tenrou S1014 (Kaneka Medics, Osaka, Japan) was used to guide the Marathon (Medtronic, Minneapolis, MN, USA) as close to the shunt point as possible. Onyx was penetrated to the shunt point, resulting in complete occlusion (Fig. 3A, B). Headache and nausea disappeared after the operation, and it was confirmed that the hyperintensity area immediately disappeared during MRI T2-weighted image and methionine-PET 6 months after the operation (Fig. 3C, D).