Early Diagnosis of Lower Limb Inflammation Foci Prior to Overt Clinical Symptoms Using Indocyanine Green (ICG) Soft Tissue Visualization

Background: Chronic venous insufficiency, foot and calf skin infections, blunt trauma and diabetes are the most common risk factors for long-lasting soft tissue inflammation leading to fibrosis, edema fluid leakage and ulcers, sporadically sepsis. The first hidden symptom of tissue changes is persistent palpation pain and hot spots of calf tissue. These are the early signs of inflammation requiring visualization of the subdermal events. 

Aim: To perform ICG visualization of lower limb tissues, lymphatics and lymph node in patients complaining of foot or calf pains, hot spots and sporadic edema. Observe changes by external compression.

Materials and methods: One hundred randomly selected patients suffering from evening heavy leg and painful calf tissues were included. Excluded were patients with acute inflammatory symptoms, venous thrombosis, profuse varices, obesity, cardiac insufficiency edema, The ICG visualization of spreading dye in tissues, lymphatics and nodes was done after injection of 0.4ml 5% ICG into toe webs of both feet and one hour walk. Pneumatic compression was applied for 30 min at 120mmHg. Pre- and post-compression pictures were taken and fluorescence level measured.

Results: In 90% of obtained images pathological changes were detected. They were: confluent spread of dye in foot dorsum, dilated foot and calf lymphatics, spotty foci in lower calf, dilated thigh lymphatics, confluent spread in  thigh and groin, outline of small inguinal nodes or their lack. Most common were changes were detected in lower calf. They were classified as a. dense, b. foggy, c. reticular, d. spotty and e. net web. The areas of images were consistently larger than the painful and hot ones. Compression brought about decrease in fluorescence by 10-20%.

Conclusions: The ICG tissue images detect clinically non-diagnosed inflammation foci in the lower limb soft tissues at sites predisposed for ulcer formation, fibrosis and lymph leakage. A hint for early therapy.