In vitro measurement of clot volume with ultrasound-calibrated 3D reconstructions.

Objective : We used 3D ultrasonographic reconstruction with manual acquisit ion to study the volume of venous clots in vitro. Material and methods : Native 2D ultrasound slices were acquired free hand for 3D reconstruction. The spatial coordinates of each slice were delivered in real time with an electromagnetic captor. We applied a standard ultraso und protocol to test the calibrated 3D reconstruction quantitatively. The v olume of 5 clots of increasing size was quantified in vitro using manual se gmentation in a double-blind manner by two independent operators. Results : The comparison tests and the interoperator regression lines evide nced good agreement between real and measured volumes. confirming the coher ence of the reconstruction protocol and the feasibility of this technique i n a routine medical setting. Intraoperator variability was 7 to 11% and int eroperator variability 16.9%. Conclusion : This calibrated 3D reconstruction is compatible with in vitro measurement of venous clots. This technique could be useful to follow the e volution of the bead of proximal deep vein thrombi in vivo. It will be more reliable with semi-automatic or even automatic segmentation becomes availa ble.