Peripheral arterial disease assessment: wall, perfusion, and spectroscopy.
BACKGROUND
Peripheral arterial disease (PAD) is characterized by lower limb arterial obstruction due to atherosclerosis and is increasingly common. Presently used methods for diagnosis and follow-up as well as for assessment of novel therapies are limited.


METHODS
Three distinct magnetic resonance examinations were developed. The first was high-resolution black-blood atherosclerotic plaque imaging of the superficial femoral artery using a surface coil and flow saturation. Second, first-pass contrast-enhanced dual-contrast perfusion imaging of the calf muscle was performed at peak exercise using a magnetic resonance (MR)-compatible pedal ergometer. Lastly, (31)P MR spectroscopy was also performed at peak exercise to measure phosphocreatine (PCr) recovery kinetics.


RESULTS
Seventeen patients (age, 63 +/- 10 yrs) with mild to moderate PAD were studied with black-blood atherosclerotic plaque imaging. Mean atherosclerotic plaque volume measured was 7.27 +/- 3.73 cm(3). Eleven patients (age, 61 +/- 11 yrs) with mild to moderate symptomatic PAD and 22 normal control subjects were studied with first-pass contrast-enhanced perfusion imaging. Perfusion index was stepwise increased from patients to normal subjects with matched workload to normal subjects at maximal exercise. For PCr recovery kinetics, 20 patients with mild to moderate PAD and 14 controls were studied. The median recovery time constant of PCr was 34.7 seconds in the controls and 91.0 seconds in the PAD patients (P < 0.0001).


CONCLUSIONS
Three distinct MR examinations of different aspects of peripheral arterial disease have been developed and tested and shown to differentiate patients with mild to moderate PAD from normal controls. Taken together, these tests are potential quantitative end points for clinical trials of novel therapies in PAD.
Kramer
Christopher M
CM
Department of Radiology, University of Virginia Health System, Charlottesville, VA 22908, USA. ckramer@virginia.edu
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D050197:Atherosclerosis / Q000378:metabolism / Q000503:physiopathology*; D003287:Contrast Media; D015444:Exercise; D005260:Female; D005263:Femoral Artery; D019786:Gadolinium DTPA; D006801:Humans; D007383:Intermittent Claudication / Q000378:metabolism / Q000503:physiopathology*; D007866:Leg / Q000098:blood supply; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000098:blood supply / Q000378:metabolism; D012372:ROC Curve; D015203:Reproducibility of Results; D018709:Statistics, Nonparametric
D003287:Contrast Media; D019786:Gadolinium DTPA