Evaluating the stage of deep vein thrombosis: the diagnostic accuracy of shear wave elastography and super-microvascular imaging.

Background: Assessing the age of deep vein thrombosis (DVT) is crucial for guiding treatment approaches. Two-dimensional shear-wave elastography (2D-SWE) and super-microvascular imaging (SMI), as emerging techniques for tissue elasticity assessment and intrathrombus microvascular analysis, are pivotal for accurate thrombus age determination. This research endeavors to classify DVT into acute, subacute, and chronic ages utilizing these imaging methods. Methods: The study is a prospective, single-center, inpatient investigation that utilized convenience sampling for participant recruitment. Patients with a symptom duration of <6 months who were found to have lower-extremity DVT on ultrasound (US) between January 2021 and March 2022 after craniocerebral trauma (CT) or bone injury (BI) operations were included in this study. Participants were divided into three groups based on the duration of DVT, measured from the first diagnosis of thrombosis by US to the follow-up with 2D-SWE and SMI: acute (≤14 days), subacute (15-30 days), and chronic (31 days to 6 months) All patients underwent 2D-SWE and SMI using an Aplio i700 Ultrasound System equipped with a PLT-1005BT line array probe. Diagnostic performance was assessed using the area under the receiver operating characteristic (ROC) curve. Results: The maximum value of the elastic modulus for DVT (DVT_Emax), the mean value of the elastic modulus for DVT (DVT_Emean), and SMI's flow distribution scoring pattern for DVT (SMI_scoring) emerged as significant predictors for acute and chronic, with high area under the ROC curve (AUC) of acute [AUC (95% confidential interval): 0.95 (0.89-0.97), 0.96 (0.91-0.98), 0.93 (0.88-0.97) in 39 patients] and chronic [AUC (95% confidential interval): 0.88 (0.81-0.93), 0.94 (0.88-0.97), 0.91 (0.84-0.95) in 51 patients], respectively. However, these indices had lower efficacy for subacute prediction [AUC (95% confidential interval): 0.51 (0.42-0.60), 0.54 (0.46-0.63), 0.53 (0.44-0.62), in 47 patients]. Combining DVT_Emean with SMI_scoring improved performance in predicting subacute: 0.90 (0.83-0.94) than related features alone. Conclusions: Both 2D-SWE and SMI can be used to assess acute and chronic DVT in patients with CT and BI after surgeries. This combination is a promising adjunctive technique for identifying the subacute phase of DVT in these patients.