Real-time Sonoelastography of the Plantar Fascia: Comparison between Patients with Plantar Fasciitis and Healthy Control Subjects

Purpose: To evaluate the use of axial-strain real-time sonoelastography in patients with plantar fasciitis compared with that in healthy control subjects. Materials and Methods: Institutional review board approval and patients' consent were obtained. Eighty feet of 80 patients (43 men, 37 women; mean age +/- standard deviation, 46.3 years +/- 8.7) with plantar fasciitis and 50 feet of 50 asymptomatic volunteers (27 men, 23 women; mean age, 44.3 years +/- 8.0) were prospectively evaluated. Individuals graded heel pain with a visual analogue scale and underwent B-mode ultrasonography (US) and real-time sonoelastography. Maximum fascial thickness was measured, and two longitudinal images were recorded with both modalities. Two radiologists who were blinded to clinical symptoms independently reviewed images for hypoechoic echotexture and fascial-border blurring at B-mode US and semiquantitative elasticity score at real-time sonoelastography (blue, 1; green, 2; red, 3), with the fascia divided into proximal, intermediate, and distal sections. Results: No differences were found for sex (P = .999) or age distribution (P = .144) between groups. Fascial thickening, hypoechoic echotexture, and fascial-border blurring at B-mode US were increased in patients versus control subjects (P < .001), and fascial thickening and hypoechoic echotexture correlated with heel pain score (r > .475, P < .001). Plantar fasciae of patients (median score, 11; interquartile interval, 10-12) were less elastic than those of control subjects (median score, 7; interquartile interval, 6-7.25) (P < .001). Image interpretation yielded high interobserver reproducibility (kappa >= .80). Pain and real-time sonoelastographic scores correlated significantly (r = 0.851, P < .001). Pain was associated with older age (t = 3.7, P < .001), fascial thickening (t = 7.3 [multiple stepwise regression model], P < .001), and total real-time sonoelastographic score (t = 10.2, P < .001) but not with sex, fascial-border blurring, or hypoechoic echotexture. Accuracy increased from 90.0% with B-mode US to 95.4% with real-time sonoelastography (P = .016). Conclusion: Real-time sonoelastography can show plantar fasciitis, increase diagnostic performance of B-mode US, and assist in cases of inconclusive B-mode US findings. (C)RSNA, 2013