3D nongadolinium-enhanced ECG-gated MRA of the distal lower extremities: preliminary clinical experience.
OBJECTIVE
To report our initial experience implementing a noncontrast-enhanced electrocardiograph (ECG) gated fast spin echo magnetic resonance angiography (MRA) technique for assessment of the calf arteries.


METHODS
Noncontrast MRA images of 36 clinical patients examined over a 6-month period were evaluated by two radiologists for length and degree of stenosis of arterial segments. Diagnostic confidence in the technique was also recorded. The reference standard was a consensus reading by both radiologists using the noncontrast technique combined with two gadolinium-enhanced techniques: bolus-chase and time-resolved imaging.


RESULTS
For stenosis evaluation the noncontrast technique demonstrated accuracy 79.4% (1083/1364), sensitivity 85.4% (437/512), and specificity 75.8% (646/852). The sequence demonstrated high negative predictive value (92.3%, 646/700). The technique had serious artifacts leading to poor diagnostic confidence in 17 patients (47.2%). These included motion (n = 7) and artifacts specific to the sequence, including inaccurate trigger delays (n = 5), linear artifact (n = 7), and vessel blurring (n = 5). When only patients in whom there was satisfactory diagnostic confidence were considered, accuracy, sensitivity, and negative predictive value were 92.2% (661/717), 92.4% (158/171), and 97.5% (503/516), respectively.


CONCLUSIONS
Our results indicate that when technically successful, noncontrast-enhanced MRA using ECG-gated fast spin echo can provide accurate imaging of the calf and pedal arteries. However, further development and optimization are needed to improve the robustness of the technique.
Lim
Ruth P
RP
Department of Radiology (MRI), New York University Medical Center, 560 First Avenue, New York, NY 10016, USA. limr02@med.nyu.edu
Hecht
Elizabeth M
EM
Xu
Jian
J
Babb
James S
JS
Oesingmann
Niels
N
Wong
Samson
S
Muhs
Bart E
BE
Gagne
Paul
P
Lee
Vivian S
VS
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D003251:Constriction, Pathologic / Q000175:diagnosis; D004562:Electrocardiography; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D007866:Leg / Q000098:blood supply*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009038:Motion; D016491:Peripheral Vascular Diseases / Q000175:diagnosis; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity