Nuclear magnetic resonance imaging: its diagnostic value in patients with congenital vascular malformations of the limbs.

Congenital vascular malformations (CVMs) of the limb include simple and cavernous hemangiomas, microarteriovenous and macroarteriovenous fistulas, venous angiomas, and mixed CVMs. In differentiating these lesions, Doppler waveform analysis, labeled microsphere studies, arteriography, closed-space phlebography, and contrast-enhanced CT scans have all been advocated, but each has significant limitations. This article evaluates the ability of magnetic resonance imaging (MRI) in characterizing CVMs. Limb CVMs were evaluated by MRI in eight patients: four in the upper and four in the lower extremity. Before MRI, seven of the patients had arteriography, five had phlebography, and five had Doppler waveform analysis. MRI showed a highly cellular network with little arteriovenous flow in five patients. In four of these, arteriography and phlebography confirmed the presence of a predominantly venous or microfistulous anomaly. In the other three patients, MRI demonstrated high-flow arterial and venous channels and were confirmed by arteriography to have macrofistulous arteriovenous malformations. In all eight patients, MRI revealed the anatomic location and the longitudinal and transverse extent of the vascular malformation as well as their relationships with contiguous muscle groups, bones, and vessels. We conclude that CVMs of the limbs can be characterized accurately with MRI, with the anatomic extent, degree of cellularity, and flow characteristics readily gauged. Because MRI provides the same basic information supplied by angiography and the noninvasive laboratory and assesses anatomic extent and cellularity, it serves well as the primary diagnostic test for suspected CVMs, particularly in infants and children in whom competitive tests pose additional limitations.