Arteriovenous Malformation

Arteriovenous malformations of large enough caliber can be well evaluated with sub-second resolution to sort out feeding arteries from draining veins (Fig. 9 a-e) [24]. This can be extremely helpful in pre-procedural or pre-operative planning for

Fig. 9a-e. Sub-second 3D MRA of a Pulmonary AVM. Selected frames from a multi-phase 3D MRA acquisition demonstrates: a (Frame 4), Early filling of the superior vena cava from the left bracheocephalic vein (arrow); b (Frame 8), Progression of the bolus into the right atrium (RA); c (Frame 12), Contrast filling the right ventricle (RV), main pulmonary artery (PA) and its branches. More specifically, filling of the pulmonary AVM (smallarrow) is noted via the right lower lobe pulmonary artery (large arrow); d (Frame 17), Persistent contrast filling of the right lower lobe pulmonary artery (large arrow) and AVM is noted with drainage via the right lower lobe pulmonary vein (smallarrow) into the left atrium; e (Frame 22), The contrast bolus is seen still within the right lower lobe pulmonary vein (small arrow) with progression of the bolus into the left atrium (LA) and left ventricle (LV)

Vascular Malformations Lower Extremity

Fig. 10a-d. AV-malformation of the lower leg in an 8-year old boy. The T2w coronal image (a) shows high signal intensity lesions of the lower leg indicative of dilated vascular structures. Time resolved MRA (Gd-BOPTA, 0.1 mmol/kg, 1.5 ml/sec) was performed before surgery or embolization to further evaluate the vascular malformation. The different phases acquired (b-d) reveal early filling of the malformation (arrows in b) and early depiction of the draining veins (arrow in d), which were indicative of AV-malformations. These were treated successfully by catheter embolization [Image courtesy of Dr. G. Schneider]

Fig. 10a-d. AV-malformation of the lower leg in an 8-year old boy. The T2w coronal image (a) shows high signal intensity lesions of the lower leg indicative of dilated vascular structures. Time resolved MRA (Gd-BOPTA, 0.1 mmol/kg, 1.5 ml/sec) was performed before surgery or embolization to further evaluate the vascular malformation. The different phases acquired (b-d) reveal early filling of the malformation (arrows in b) and early depiction of the draining veins (arrow in d), which were indicative of AV-malformations. These were treated successfully by catheter embolization [Image courtesy of Dr. G. Schneider]

Pictures Images Vascular Malformation

treatment of pulmonary AVM cases such as those encountered in Osler-Weber-Rendu disease, however since treatment of even 5mm large AVMs is recommended high spatial resolution imaging is necessary in addition. This technique is also applicable to other body AVM's and in practice should be applicable to intracranial AVM's as well (Fig. 2). Some centers are applying this technique to initial evaluation of dialysis fistulas prior to definitive in-terventional procedures. The MRA with its time resolved components has the capability to demonstrate whether the problem is arterial stenosis, venous stenosis, thrombosis, or a combination.

Especially in children, in which vascular malformations are quite frequent, time-resolved contrast enhanced MRI offers the possibility to no in-

vasively evaluate the vascular anatomy of a lesion and to plan further therapy without the risk of an interventional procedure (Fig. 10).

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