Time-resolved MR angiography of renal artery stenosis in a swine model at 3 Tesla using gadobutrol with digital subtraction angiography correlation.
OBJECTIVE
To establish the minimum dose required for detection of renal artery stenosis using high temporal resolution, contrast enhanced MR angiography (MRA) in a porcine model.


METHODS
Surgically created renal artery stenoses were imaged with 3 Tesla MR and digital subtraction angiography (DSA) in 12 swine in this IACUC approved protocol. Gadobutrol was injected intravenously at doses of 0.5, 1, 2, and 4 mL for time-resolved MRA (1.5 × 1.5 mm(2) spatial resolution). Region of interest analysis was performed together with stenosis assessment and qualitative evaluation by two blinded readers.


RESULTS
Mean signal to noise ratio (SNR) and contrast to noise ratio (CNR) values were statistically significantly less with the 0.5-mL protocol (P < 0.001). There were no statistically significant differences among the other evaluated doses. Both readers found 10/12 cases with the 0.5-mL protocol to be of inadequate diagnostic quality (κ = 1.0). All other scans were found to be adequate for diagnosis. Accuracies in distinguishing between mild/insignificant (<50%) and higher grade stenoses (>50%) were comparable among the higher-dose protocols (sensitivities 73-93%, specificities 62-100%).


CONCLUSIONS
Renal artery stenosis can be assessed with very low doses (~0.025 mmol/kg bodyweight) of a high concentration, high relaxivity gadolinium chelate formulation in a swine model, results which are promising with respect to limiting exposure to gadolinium based contrast agents.
Scott and White Clinic and Hospital and Department of Radiology, Texas A&M University Health Science Center, Temple, TX, USA.
John N
JN
Morelli
Fei
F
Ai
Val M
VM
Runge
Wei
W
Zhang
Xiaoming
X
Li
Peter
P
Schmitt
Gary
G
McNeal
Henrick J
HJ
Michaely
Stefan O
SO
Schoenberg
Matthew
M
Miller
Clint M
CM
Gerdes
Spencer T
ST
Sincleair
Heidi
H
Spratt
Ulrike I
UI
Attenberger
D000465:Algorithms; D015901:Angiography, Digital Subtraction; D000818:Animals; D003287:Contrast Media / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D005260:Female; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D009942:Organometallic Compounds / Q000008:administration & dosage*; D012078:Renal Artery Obstruction / Q000175:diagnosis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013552:Swine
D003287:Contrast Media; D009942:Organometallic Compounds; C090600:gadobutrol