Rotator cuff in asymptomatic volunteers: Contrast-enhanced US depiction of intratendinous and peritendinous vascularity

Purpose: To test the hypothesis that regional variations in supraspinatus tendon vascularity exist and can be imaged and quantified in asymptomatic individuals by using contrast material-enhanced ultrasonography (US). Materials and Methods: After institutional review board approval and informed consent were obtained, 31 volunteers aged 22-65 years (mean age, 41.5 years) underwent lipid microsphere contrast-enhanced shoulder US performed with an L8-4 transducer operating in contrast harmonic mode and a mechanical index of 0.07 in a HIPAA-compliant protocol. Images were obtained in the volunteers at rest and after exercise. Quantitative analysis was performed by using the time-enhancement postcontrast data derived from four regions of interest (ROIs): bursal medial, articular medial, bursal lateral, and articular lateral. Two 2-minute acquisitions were performed after each contrast material bolus. Baseline enhancement and peak enhancement for each ROI were estimated from these acquisitions. Baseline gray-scale and power Doppler US images of the supraspinatus tendon were obtained by using an L12-5 transducer. The Mann-Whitney nonparametric test was used to test for significant differences between ROIs in all volunteers. Results: In the volunteers at rest before exercise, significant variations in regional enhancement between the articular medial zone and both the bursal medial zone (P = .002) and the bursal lateral zone (P = .003) were observed. Differences in enhancement between the articular medial and articular lateral zones approached significance. Greater differentiation (P < .001) was observed after exercise, with a significant increase in apparent enhancement in each ROI in all volunteers. Conclusion: This study revealed the spatial distribution of the blood supply to the supraspinatus tendon in asymptomatic individuals. The addition of exercise to the protocol resulted in a significantly increased level of enhancement compared with that at rest and enabled more sensitive assessment of intratendinous and peritendinous vascularity. (C) RSNA, 2008.