| Objective: To investigate the types and changes of the acoustic quantified parameters of time-intensity curve (TIC) in diagnosing focal liver lesions with a second-generation contrast angent (SonoVue), pulse-inversion harmonic (PIH) imaging and acoustic densitometry technique. Contrast-enhanced ultrasound (CEUS) features of different course of disease and different tissue origin in the malignant tumors were analyzed quantitatively, to supply basis for clinical diagnosis, choosing the therapy plan and assessing prognosis.Methods: Ninety-four patients with 46 benign lesions and with 48 malignant lesions were examined using PIH imaging after an intravenous administration of SonoVue. All patients were fasting for eight to twelve hours before examinations. At first, 2D gray-scale sonography was used to depict the position, size, quantity and inner echo, the blood supply of lesions were displayed with color Doppler flow imaging (CDFI) and color power angiography (CPA), then transformed to the state of PIH after the best section was selected. CEUS PIH examinations were performed with a low mechanical index of 0.08. A 2.4 ml intravenous bolus injection of SonoVue was used, followed by a flush of 5ml of saline (shook 5s before injection, then injected quickly within 3s) at the same time, we observed dynamic enhancement course of liver lesions. Acoustic densitometry technique was used to analyze the imaging after CEUS. According to TIC, the types of TIC, the acoustic quantified parameters, the peak intensity and the intensity every 10s were obtained and analyzed statistically.Results:1 TIC appeared quick-ascending and quick-descending types in the malignant lesions mainly but slow-ascending and slow-descending types with flattening tops after reaching peak intensity in the benign lesions.2 Time to arrival in 48 cases with the malignant lesions were significantly earlier than 46 cases with the benign lesions (P<0.05). The acoustic quantified parameters including peak time, time of enhancement, time to wash-out and half time of descending in the malignant lesions were significantly earlier than those in the benign lesions respectively (P<0.001). The ascending slope and wash-out 50% slope in the malignant lesions were significantly higher than those in the benign lesions(P<0.001).3 In the malignant lesions, primary hepatic carcinoma and metastasis liver cancer mostly showed hyper-enhancement on peak time, the percentage was 70% (38/54). In this study, 25 cases of 46 benign lesions (54%) mainly showed iso- enhancement on peak time, the secondary was hyper- enhancement, the percentage was 35% (16/46). 4 In the late arterial phase (30s, 40s after injection), there was no significant difference of the intensity between benign lesions and malignant lesions(P>0.05). There were hyper- perfusion in the malignant lesions and hypoperfusion in the benign lesions in the early arterial phase(10s, 20s after injection), while there were hypoperfusion of the former and hyperperfusion of the latter in the portal and the late phase (after 40s) (P<0.01).5 There was a typical or a atypical type of TIC according to the different course of disease and different tissue origin in the malignant tumors. All 48 cases with the malignant lesions showed quick-ascending types. 16 cases with primary hepatic carcinoma (80%) and 23 cases with metastasis liver cancer (82.1%) showed quick-descending types, their peak intensity declined a half in the portal phase. The peak intensity of the other 4 cases with small hepatocellular carcinoma (20%) and 5 cases with metastasis liver cancer (17.9%) declined a half in the late phase, TIC showed slow-descending types.6 The half time of descending in the small hepatocellular carcinoma were significantly later than those in the non-small hepatocellular carcinoma(P<0.01). There were no significant difference of the other six acoustic quantified parameters between them(P>0.05). The half time of descending in 28 liver metastases were significantly earlier than those in 20 hepatocellular carcinoma(P<0.05) and there were no significant difference of the other six acoustic quantified parameters between them(P>0.05). The intensity of 20s after the injection in the hypoperfused metastases were significantly lower than those in primary hepatic carcinoma and hyperperfused metastases(P<0.01), while there were no significance between the two latter(P>0.05). There were no significant difference of the intensity of the other times after the injection between primary hepatic carcinoma and metastasis liver cancer.Conclusions:1 The quantity, structure and distribution of the vessels in the benign and malignant focal liver lesions were the pathologic bases of CEUS to quantitatively assess blood supply of lesions.2 Acoustic densitometry technique based on drawing TIC could avoid the influence coming from the subjectivity and the visual ability, to assess the results after CEUS of the benign and malignant focal liver lesions quantitatively and objectively.3 There were different characteristics in types and acoustic quantified parameters of TIC between the benign focal liver lesions and the malignant lesions, which were the bases to differentiate the benign and malignant focal liver lesions correctly. The atypical cases should be paid more attention to when the results of CEUS were quantitatively analyzed in order to reduce the misdiagnosis.4 The type of TIC and the change characteristics of the acoustic quantified parameters could reflect the flow distribution and the quantity of perfusion of the tiny vessels in hepatic tumors to supply objective evidence for differential diagnosis of benign and malignant focal liver lesions, then being help for improving the clinical diagnosis level and therapy level. |
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