Multimodal Ultrasound for Evaluating the Triceps Surae in Patients With Intramuscular Venous Dilatation and Intramuscular Venous Thrombosis of the Lower Extremity.

OBJECTIVE: To evaluate the applicability and diagnostic performance of multimodal ultrasound in assessing intramuscular venous disorders of the lower extremity. METHODS: This retrospective study included 142 individuals who underwent lower-limb venous ultrasonography: 50 with intramuscular venous dilatation, 42 with intramuscular venous thrombosis (IMVT), and 50 healthy controls. Intramuscular vein diameter, muscle thickness, and muscle stiffness of the triceps surae were evaluated using multimodal ultrasonography. Ultrasound parameters and biochemical markers were compared among the three groups. RESULTS: Compared with the dilatation (13.74 ± 3.00 mm, 18.23 ± 3.04 mm) and control groups (13.69 ± 2.71 mm, 16.58 ± 2.93 mm), the IMVT group exhibited reduced medial gastrocnemius (MG) and soleus muscle thicknesses (12.36 ± 2.95 mm and 15.35 ± 3.04 mm, respectively; p < 0.05). The dilatation group had greater soleus thickness than the control group (18.23 ± 3.04 vs. 16.58 ± 2.93 mm, p < 0.05). MG shear wave velocity (SWV) was lower in the IMVT group than in the control group (1.80 [1.69, 1.96] vs. 1.99 [1.74, 2.26] m/s, p < 0.05), whereas soleus SWV was lower in the IMVT group but higher in the dilatation group than in the control group (1.95 [1.75, 2.59] vs. 3.10 [2.19, 3.73] vs. 2.67 [2.14, 3.19] m/s; p < 0.05). MG vein diameter, soleus vein diameter, soleus SWV, and D-dimer levels were key factors influencing IMVT (p < 0.05). A logistic regression model combining these indicators achieved an area under the curve of 0.934 (95% CI: 0.888-0.972) for differentiating IMVT. CONCLUSION: Multimodal ultrasound represents a useful adjunctive tool for screening individuals at high risk of IMVT.