In vivo vibroacoustography of large peripheral arteries.
OBJECTIVE
Vibroacoustography allows imaging of objects on the basis of their acoustic signal emitted during low-frequency (kHz) vibrations produced by 2 intersecting ultrasound beams at slightly different frequencies. This study tested the feasibility of using vibroacoustography to distinguish between normal and calcified femoral arteries in a pig model.


METHODS
Thirteen normal porcine femoral arteries, 7 with experimentally induced arterial calcifications, and 1 control artery injected with saline only were scanned in vivo. Images were obtained at 45 kHz using a 3 MHz confocal transducer. The acoustic emission signal was detected with a hydrophone placed on the animal's limb. Images were reconstructed on the basis of the amplitude of the acoustic emission signal. Vessel patency, vessel dimensions, and the extent of calcified plaques were confirmed in vivo by angiography and conventional ultrasound. Excised arteries were reexamined with vibroacoustography, X-ray radiography, and histology.


RESULTS
In vivo, vibroacoustography produced high-resolution, speckle-free images with a high level of anatomic detail. Measurements of femoral artery diameter were similar by vibroacoustography and conventional ultrasound (mean difference +/- SD, 0.1 +/- 0.4 mm). Calcified plaque area measured by different methods was comparable (vibroacoustography, in vivo: 1.0 +/- 0.9 cm; vibroacoustography in vitro: 1.1 +/- 0.6 cm2; X-ray radiography: 0.9 +/- 0.6 cm2). The reproducibility of measurements was high. Sensitivity and specificity for detecting calcifications were 100% and 86%, respectively, and positive and negative predictive values were 77% and 100%, respectively.


CONCLUSIONS
Vibroacoustography provides accurate and reproducible measurements of femoral arteries and vascular calcifications in living animals.
Pislaru
Cristina
C
Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA. pislaru.cristina@mayo.edu
Kantor
Birgit
B
Kinnick
Randall R
RR
Anderson
Jill L
JL
Aubry
Marie-Christine
MC
Urban
Matthew W
MW
Fatemi
Mostafa
M
Greenleaf
James F
JF
D000704:Analysis of Variance; D000818:Animals; D002114:Calcinosis / Q000000981:diagnostic imaging*; D004195:Disease Models, Animal; D054459:Elasticity Imaging Techniques; D005263:Femoral Artery / Q000000981:diagnostic imaging*; D013552:Swine