MR angiography versus color Doppler sonography in the evaluation of renal vessels and the inferior vena cava in abdominal masses of pediatric patients

OBJECTIVE. Involvement of renal vessels and the inferior vena cava (IVC) pl ays a decisive role during operative planning for removal of abdominal mass es in pediatric patients. Advantages and limitations of MR angiography and color Doppler sonography for determining these factors were evaluated. MATERIALS AND METHODS. MR angiography and color Doppler sonography were per formed preoperatively in 42 neonates, infants, and children with abdominal masses and were compared with spin-echo MR imaging and with surgical findin gs. Variables evaluated were anatomic variants, vessel displacement, patenc y of vessels, collateral circulation, and intravascular tumor extension. Qu ality of vessel visualization was assessed in vessels not affected by tumor . RESULTS, In 88% of unaffected renal vessels, the entire vessel course could be visualized on MR angiography compared with 58% on color Doppler sonogra phy and 43% on spin-echo MR imaging. In four of nine cases, color Doppler s onography revealed an accessory renal artery, whereas MR angiography reveal ed these variants in seven of nine cases. MR angiography showed 79% and col or Doppler sonography 66% of displaced vessels. Unlike MR angiography, colo r Doppler sonography did not reveal five stenotic renal veins because they could not be completely imaged. In two cases, however, MR angiography false ly indicated an occlusion of the IVC, whereas color Doppler sonography show ed residual flow. CONCLUSION, Anatomic variants, vessel displacement, collateral circulation, and neoplastic vessel infiltration were revealed more accurately by MR ang iography than by color Doppler sonography. In cases in which patency of the IVC is unclear on MR angiography, color Doppler sonography should also be performed.