PMC9217143_01
Magnetic resonance imaging on admission.
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a) T1-weighed imaging, axial view. The outlet of the developmental venous anomaly (DVA) (arrow), medially adjacent to the left trigeminal nerve, does not show intraluminal hyperintensity, implying that no thrombus is evident inside the stenotic draining vein (arrowhead).
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b) T2-weighted imaging, axial view. A prominent draining vein from the left cerebellar peduncle indicates the DVA (arrow). Note the severe stenosis at the junction of the DVA and cavernous sinus (arrowhead).
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c) Fluid-attenuated inversion recovery imaging. Faint hyperintensity is detected adjacent to the DVA.
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d) T2* imaging shows moderately hypointense stippled lesions, compatible with a diagnosis of CCT.
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e) Gadolinium-enhanced T1-weighted imaging shows faint stippled brush-like enhancement from the pons to the left cerebellar peduncle. This image also shows the DVA.
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f) The cerebral blood volume computed with T2*-based perfusion-weighted imaging. Elevated cerebral blood volume is observed in the left superior cerebellar peduncle and the central lobule of the vermis (double arrows). The large signal defect in the pons corresponds to the T2* hypointense lesion.
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g) The mean transit time computed with perfusion-weighted imaging. Prolonged mean transit time is also confirmed in the same region as seen in Fig. 1f (double arrows).
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MRI of the brain on admission showed a 4-cm hypointense mass occupying the pons and the left cerebellar peduncle (Fig. 1a-e). T2-weighted imaging demonstrated a prominent draining vein out of the mass into the cavernous sinus (Fig. 1b). T1-weighted imaging did not show any intraluminal hyperintensity in the draining vein, implying that venous thrombosis was unlikely coexistent (Fig. 1a). Fluid-attenuated inversion recovery imaging demonstrated minimal intraparenchymal hyperintensity adjacent to the DVA (Fig. 1c). Gadolinium-enhanced T1-weighted imaging also showed the draining vein with a faintly enhancing surrounding mass corresponding to the low-intensity area on T2* imaging (Fig. 1d and e). Perfusion-weighted imaging exhibited elevated cerebral blood volume and prolonged mean transit time in the left superior cerebellar peduncle and the central lobule of the vermis, denoting venous congestion (Fig. 1f and g).
Digital subtraction angiography and three-dimensional rotational angiography.
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a) Left vertebral arteriography, lateral view. In the arterial-to-capillary phase, no capillary stain or arteriovenous shunt is observed in the brainstem parenchyma.
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b) Left vertebral arteriography, lateral view, venous phase. The angiogram shows a prominent vein draining from the pons into the cavernous sinus (arrow). The outlet of the DVA is markedly stenotic (arrowhead).
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c) Late-phase venogram, lateral view, showing persistent pooling of the contrast medium in the DVA, particularly in the intraparenchymal segment.
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d) Sagittal multiplanar reconstruction of three-dimensional rotational venography of the DVA shows the stenotic site at the veno-dural junction. The arrow and arrowhead indicate the same structures as in Fig. 2b.
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e) Axial multiplanar reconstruction of the three-dimensional rotational venography of the DVA shows a typical finding of DVA (caput medusae).
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Still, the outlet of the DVA was severely stenotic in the proximity of the cavernous sinus (Fig. 2a-d) and caused significant flow stagnation (Fig. 2e).