The value of contrast-enhanced ultrasound in the diagnosis of microcirculatory perfusion abnormalities in diabetic foot

Background

Diabetic foot is one of the most serious complications of type 2 diabetes mellitus (T2DM), and its incidence is increasing in China. Early detection of abnormal microcirculation in the foot is very important for the prevention and treatment of diabetic foot.

Objective

To investigate the value of contrast-enhanced ultrasound (CEUS) in diagnosing microcirculatory alterations in the dorsum of the foot for patients with type 2 diabetes mellitus (T2DM).

Methods

Eighty-eight T2DM patients were included, among them 30 patients sustained diabetes mellitus without complications (group A), 28 with lesions in the dorsum of the foot (no acute infection) that can be classified as Wagner grade 0 ~ 1 (group B), and 30 with lesions in the dorsum of the foot that can be classified as Wagner grade 2–5 (group C). Another 30 healthy adults were included as the control group. All subjects underwent CEUS to examine the dorsalis pedis arteries and blood perfusion to the underlying soft tissues. Parameters of the time-intensity curve (TIC), including rise time (RT), ascending slope (AS), time to peak (TTP), peak intensity (PI), area under the curve (AUC), and half of drop time (DT/2) were analyzed.

Results

The analysis of TIC data of the dorsalis pedis arteries showed that group C had decreased AS, PI, and AUC and increased TTP, RT, and DT/2 compared with groups A, B, and the control group; the differences were statistically significant (p < 0.05). The analysis of TIC data of the perfusion to the underlying soft tissues showed that AS, PI, and AUC decreased from the control group through group A, B, and then C; the differences were all statistically significant (p < 0.05). The TIC data were correlated with the severity of microcirculatory impairment in the dorsum of the foot and among them the AUC, PI, and AS had higher predictive value.

Conclusions

Microcirculatory impairment in the dorsum of the foot in T2DM patients presents itself as “delayed wash-in, delayed wash-out, and weak enhancement” on CEUS images. CEUS can provide quantification of the microcirculatory changes in the soft tissues in the dorsum of the foot and reflect the differences of microcirculatory perfusion across different grades of lesions.