title: Catheter-directed MR angiography and cross-sectional imaging for the assessment of renal artery stenosis.
abstract: OBJECTIVE
  Catheter-directed intraarterial (IA) gadolinium (Gd)-enhanced gradient-echo (GRE) imaging has been used in the setting of magnetic resonance (MR) imaging-guided endovascular procedures for two-dimensional (2D) or three-dimensional (3D) depiction of blood vessels. In a swine model, the hypothesis was tested that the combination of 2D IA GRE and 2D cross-sectional steady-state free precession (SSFP) imaging improves assessment of renal artery stenosis (RAS) compared with 3D IA GRE imaging alone.
  
  
  METHODS
  Bilateral RAS was surgically induced in seven pigs. Detection of stenoses was then compared between the combination of 2D projection IA GRE and cross-sectional 2D SSFP imaging without contrast agent and 3D IA GRE alone. Radiographic digital subtraction angiography (DSA) was employed as the reference standard. Linear regression was used to compare stenosis measurements, with an alpha of 0.05.
  
  
  RESULTS
  Radiographic DSA and MR imaging were successful in the seven animals (14 stenoses). With use of linear regression analysis, the combination of 2D IA GRE and 2D SSFP imaging had a higher r(2) (0.87 vs 0.72) and a slope closer to unity (1.02 vs 0.77) compared with 3D IA GRE imaging alone. When comparing intercepts, the regression line for SSFP significantly differed from that of 3D IA GRE imaging (P < .05).
  
  
  CONCLUSIONS
  The combination of 2D IA GRE and cross-sectional 2D SSFP imaging improves the accuracy of RAS detection compared with IA 3D IA-GRE alone.
authors.affiliation: Department of Radiology, Northwestern University, Suite 700, 448 East Ontario Street, Chicago, Illinois 60611, USA. reed@northwestern.edu
authors.forename: Reed A
authors.initials: RA
authors.lastname: Omary
authors.forename: Brian E
authors.initials: BE
authors.lastname: Schirf
authors.forename: Jordin D
authors.initials: JD
authors.lastname: Green
authors.forename: Yashpal S
authors.initials: YS
authors.lastname: Kanwar
authors.forename: Steven M
authors.initials: SM
authors.lastname: Shea
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Carroll
authors.forename: James
authors.initials: J
authors.lastname: Carr
authors.forename: Debiao
authors.initials: D
authors.lastname: Li
mesh_terms: D019412:Anatomy, Cross-Sectional; D015901:Angiography, Digital Subtraction; D000818:Animals; D002406:Catheterization, Peripheral; D003287:Contrast Media; D004195:Disease Models, Animal; D019786:Gadolinium DTPA; D007089:Image Enhancement; D021621:Imaging, Three-Dimensional; D007269:Injections, Intra-Arterial; D016014:Linear Models; D018810:Magnetic Resonance Angiography; D012078:Renal Artery Obstruction / Q000175:diagnosis*; D013552:Swine
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA