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. SUPPLEMENTAL MATERIAL http://radiology.rsnajnls.org/cgi/content/full/2483071400/DC1.