CONTRAST-ENHANCED PORTAL MAGNETIC RESONANCE ANGIOGRAPHY IN DOGS WITH SUSPECTED CONGENITAL PORTAL VASCULAR ANOMALIES WILFRIED MAI,CHICK WEISSE Contrast-enhanced multiphase magnetic resonance angiography (CE-MRA) was used in 17 dogs with a suspected congenital portal vascular anomaly. Portal vascular anomalies were identified in 16 of the 17 dogs. Eleven had a single intrahepatic portocaval shunt (two central divisional, three right divisional, and six left divisional), one dog had a double intrahepatic portocaval shunt, one dog had a hepatic arteriovenous malformation, one dog had a complex intrahepatic porto-caval shunt. Two dogs had an extrahepatic portosystemic shunt and no shunt was identified in one dog. Total imaging time was o10 min and image quality was good to excellent in all dogs. Portal CE-MRA is a feasible, fast and non invasive technique to diagnose portal vascular anomalies in dogs, with a large field-of-view and good anatomic depiction of the abnormal vessels. Based on these results, CE-MRA is an efficient imaging technique for the diagnosis of portal vascular anomalies in dogs. r 2010 Veterinary Radiology & Ultrasound, Vol. 52, No. 3, 2011, pp 284–288. Key words: arteriovenous fistula, dogs, gadolinium, magnetic resonance angiography, portosystemic shunts. P ORTAL VASCULAR ANOMALIES in the dog and cat include congenital or acquired porto-systemic shunts, portal venous hypoplasia (formerly called micro-vascular dyspla- sia), noncirrhotic portal hypertension with portal vein atresia and hepatic arteriovenous malformation. 1–9 Vascular opacification with contrast medium to identify abnormal anatomy can be replaced with computed tomography angiography or magnetic resonance angio- graphy (MRA), which are noninvasive. In addition, as interventional procedures are becoming more available to treat portosystemic shunts, minimally invasive imaging techniques that provide anatomic depiction and precise measurements of the abnormal vessels are needed. 10–16 Contrast-enhanced magnetic resonance angiography (CE-MRA) can provide excellent assessment of portal vascular anatomy in short acquisition times. 17,18 CE-MRA has surpassed noncontrast MRA techniques in many applications. 19–21 Although magnetic resonance imaging is used frequently in veterinary medicine, there is only limited information on the use of MRA. 17,18,22–30 Our objective was to evaluate CE-MRA for the diagnosis of congenital hepatic vascular diseases in dogs. Materials and Methods Seventeen dogs suspected of having congenital vascular liver disease were evaluated. Inclusion criteria were: clinical signs consistent with hepatic vascular disease and elevated circulating bile acids. There were eight males and nine females, with age ranging between 4 and 36 months (median 7 months). Breeds were: Brittany spaniel (n ¼ 2), Golden Retriever (n ¼ 2), Labradoodle (n ¼ 2), Bernese mountain dog (n ¼ 2), Labrador mixed dog (n ¼ 2), Ger- man shepherd (n ¼ 1), Pomeranian (n ¼ 1), Boxer (n ¼ 1), Labrador (n ¼ 1), Portuguese water dog (n ¼ 1), Maltese (n ¼ 1), Havanese (n ¼ 1). Whenever possible, MRA findings were confirmed at surgery or with invasive angiography during coil embolization. Anesthesia and imaging protocols were similar to those described previously. 18 Briefly, a three plane 2D T2 Ã - weighted gradient echo localizer was used to plan the MRA acquisition. For CE-MRA, a 3D Fast Spoiled Gradient Recalled Echo (3D FSPGR) sequence with elliptic centric view ordering of k-space was used with parallel acquisition (array spatial sensitivity encoding technique). The 3D volume for MRA was prescribed in the dorsal plane, and positioned to cover as much of the liver as possible in the dorsal to ventral direction, and including at least the confluence of the left hepatic vein cranially and the splenoportal confluence caudally. In each dorsal plane, phase encoding was left to right and This study was funded by a grant from the American Kennel Club/ Canine Health Foundation (ACORN No. 1160-A). Partial results from this study were presented at the ACVR Annual Scientific Meeting, San Antonio, TX, August 2008. Address correspondence and reprint requests to Dr. Wilfried Mai, at the above address. E-mail: wmai@vet.upenn.edu Received July 23, 2010; accepted for publication October 26, 2010. doi: 10.1111/j.1740-8261.2010.01771.x From the Rosenthal Imaging and Treatment Center, University of Pennsylvania, School of Veterinary Medicine, Philadelphia, PA 19104 (Mai), and The Animal Medical Center, New York, NY 10065 (Weisse). 284