AVM (within the third ventricle)

AVM-third-ventricle-Feb-2013.jpg

Image 1

Clinical History: 
A 21 year-old man, presenting with syncope

Diagnosis:
AVM (within the third ventricle)

MR Technique: 
2D FSE T2- and SE T1-weighted axial images, 5 mm in slice thickness, acquired at 1.5 T on a Siemens Espree MR unit are presented. Sequence parameters were TR/TE = 5800/93 and 500/12, with scan times of 2:37 and 3:44 respectively.

Imaging Findings:
A nidus of vessels (serpiginous in nature, with low signal intensity due to fast flow) are noted predominantly within the third ventricle on both T2- and pre-contrast T1-weighted scans. Enlarged bilateral internal cerebral veins were also noted draining the lesion (scans not shown). Non-contrast CT can miss AVMs, due to relative isointensity of the vessels with normal brain parenchyma. However in this instance, a portion of the AVM could be identified on CT due to slight hyperintensity, however the nature of the lesion was not evident (scans not shown).