Brain stem developmental venous anomaly (DVA) and a suspected topographically associated cavernous angioma, case 2

This 66 year old male was hospitalized for sudden onset of gait disturbances followed by vomiting and loss of consciousness.
At physical examination he was alert again but had nystagmus and diplopia as well as other signs of cerebellar dysfunction.
Emergency CT scan revealed a large hematoma in the brain stem, with a second area of intraparenchymal hemorrhage in the right cerebellar hemisphere. The patient improved clinically.
Follow-up MRI was performed 8 weeks later demonstrating a complete resorption of both hematomas with the suggestion of a DVA. Although the latter was quite evident on the subsequent MRA, conventional catheter angiography was still performed to confirm the diagnosis, as this case happened at the beginning of our MRA experience.

(Brain stem DVA, 0.5T)
Fig.1 Sagittal non-enhanced T1-weighted spin-echo images. Small, slightly irregular hypointense area (cavernous angioma?) in the center of the pons (yellow arrow) adjacent to a linear hypointense structure (transpontine collector of the DVA) leading towards the anterior surface of the brain stem (blue arrow).
Fig.2 Transverse proton density (left) and T2-weighted (right) fast spin-echo images. Same observations as on Fig. 1 with suggestion of the caput medusae at the floor of the 4th ventricle extending to the left middle cerebellar peduncle. A faintly hyperintense area is seen the latter location around a dilated medullary vein (arrow).
Fig.3 Gadolinium-enhanced, single slab 3D TOF image (transverse targeted MIP). Clear visualization of the previously suspected brain stem DVA exhibiting all of the characteristic features.
Fig.4 Sagittal and coronal targeted MIP reconstructions correlate well with the corresponding conventional angiographic (DSA) images (see Fig.5)
Fig.5 Lateral and a-p views of the brain stem DVA by conventional, catheter based cerebral angiography (left vertebral artery injection).
Fig.6 Transverse targeted MIP image from a single slab 3D TOF acquisition without intravenous Gadolinium injection (upper image) fails to demonstrate the DVA, due to intravolume spin saturation, a typical problem with the single slab technique. Compare this to a similar, but Gadolinium-enhanced 3D TOF MIP image (below), which clearly demonstrates the DVA (arrow).
Fig.7 Sagittal targeted images from a single slab 3D TOF acquisition without (above) and with (below) intravenous Gadolinium injection. Same observations as on Fig.6.
Fig.8 Non-enhanced sagittal 2D Phase Contrast MRA image (Venc: 15 cm/s). This technique also fails to demonstrate the brain stem DVA, most probably due to inappropriate (too high) Venc value selection. Note, however, that on this MR system the lowest selectable Venc value was 10 cm/s at the time of the examination. With recent hardware and software enhancements Venc values as low as 1 cm/s are now available.
N.B. Although never proved confidently, this case is also thought to represent topographical association of a DVA with a small cavernous angioma in the pons.

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