Contrast-enhanced sonography versus biopsy for the differential diagnosis of thrombosis in hepatocellular carcinoma patients

Figure 1 Study design. PVT FNB: Portal vein thrombus fine needle biopsy; CEUS: 2nd generation Contrast-Enhanced US (CEUS) of thrombus; ¹Guiding needle on portion of thrombus showing on CEUS precocious iso or hyperenhancement pattern; ²No increase in size and distribution with preservation of vessel wall or recanalization/shrinkage, or disappearance of a PVT within the 6 mo of follow-up were accepted as proof of a benign portal vein thrombus; ³No change in feature of thrombus and in the diameter of the segment of involved vein at 6 mo of follow-up; ⁴Increase in size with infiltration of perivascular parenchyma and interruption of vessel wall was US features indicative of malignant thrombosis.

Figure 2 Summary of combined test results. ¹Iso, hyper, or hypoenhancement pattern of thrombus compared to the surrounding parenchyma; ²Reference standard of benign thrombosis is a US evidence of evolving thrombus: no increase in size or distribution with vessel wall preservation or recanalization/shrinkage, or disappearance of a PVT within the 6 mo of follow-up were accepted as evidence of a benign portal vein thrombus; ³Us image of evolution, indicating malignant thrombosis: increase in size with infiltration of perivascular parenchyma and interruption of vessel wall was US features of malignant thrombosis; ⁴No change in thrombus image and in the diameter of the segment of vein involved at 6 mo of follow-up; ⁵PVT FNB were repeated guiding the needle to the thrombus territories with enhancing pattern.

Figure 3 Benign thrombus. A: On sonography lumen of portal vein is partially filled with hypoechoic material representing occlusive thrombus; B: Color Doppler ultrasound reveals color signals only within a portion of portal lumen; C: Contrast-enhanced sonography scan during portal phase reveals uniformly non-enhancing area within portal vein, perfectly reproducing the benign thrombus.

Figure 4 Malignant mosaic thrombus. A: Sonography scan reveals isoechoic area within portal lumen representing thrombus; B: Contrast enhanced sonography scan during late arterial phase reveals thrombus as predominantly enhancing area, indicative of arterial neovascularization (malignant thrombosis) with some non-enhancing areas of the thrombus (mosaic pattern).

Figure 5 Malignant thrombus. A: sonography reveals echogenic area (thrombus) within vessel lumen; B: during arterial phase of contrast-enhanced sonography the diffusely enhanced area representing thrombus with internal neovascularity.