Renal artery stenosis evaluated with 3D-Gd-magnetic resonance angiography using transstenotic pressure gradient as the standard of reference. A multireader study.
OBJECTIVE
To evaluate 3D-Gd-magnetic resonance angiography (MRA) in detecting hemodynamically significant renal artery stenosis (RAS).


METHODS
Thirty patients evaluated for atherosclerotic RAS by MRA and digital subtraction angiography (DSA) were retrospectively included. Standard of reference for hemodynamically significant RAS was a transstenotic gradient of 15 mmHg. DSA visualized 60 main renal arteries and 9 accessory arteries. Pressure gradient measurement (PGM) was available from 61 arteries. Three radiologists evaluated all examinations independently in a blinded fashion.


RESULTS
RAS was present in 26 arteries. On MRA, each reader identified 4 of 9 accessory renal arteries, a detection rate of 44%. The three readers correctly classified 22/25/22 of the 26 vessels with a significant gradient as > or =60% RAS and 31/25/32 of the 35 with no significant gradient as < 60% RAS on MRA. Interobserver agreement was substantial. MRA image quality was adequate for RAS evaluations in all patients. ROC curves indicated that MRA is an adequate method for evaluating RAS. When screening for RAS, a 50% diameter reduction cut-off is better than 60%. RAS with 40-80% diameter reductions accounted for 65% of discrepancies.


CONCLUSIONS
MRA is an adequate method for evaluating RAS limited mainly by poor detection rate for accessory renal arteries.
Eklöf
H
H
Department of Radiology, Akademiska sjukhuset, Uppsala, Sweden. hampus.eklof@radiol.uu.se
Ahlstrom
H
H
Bostrom
A
A
Bergqvist
D
D
Andrén
B
B
Karacagil
S
S
Nyman
R
R
D000368:Aged; D000369:Aged, 80 and over; D015901:Angiography, Digital Subtraction; D001794:Blood Pressure / Q000502:physiology; D003097:Collateral Circulation / Q000502:physiology; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000706:statistics & numerical data; D018810:Magnetic Resonance Angiography / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D012077:Renal Artery / Q000503:physiopathology; D012078:Renal Artery Obstruction / Q000175:diagnosis* / Q000503:physiopathology; D012189:Retrospective Studies
D003287:Contrast Media; D019786:Gadolinium DTPA