| Objective: To study: 1. try to find the sonogram features of liver with tissue harmonic imaging (THI) and compare the THI with the convention fundamental imaging (FI) of liver. 2. Characterize the diffuse liver diseases with quantitative methods meanwhile try to chose good parameters of tissue characterization for diffuse liver diseases. 3. Analyze quantitatively the focal liver lesions with THI and explore the mechanism underlying them. 4. Determine the imagine feature of hepatocellular carcinoma (HCC) with THI and the relationship with their pathology.Methods: 1. Research subjects: From Dec. 2000 to Dec. 2001, total 194 Inpatient and outpatient in our hospital, average age 48+12.5y, were employed in the study. 41 were HCC, all identified by operation or pathology. 77 were liver cirrhosis, conformed to clinical diagnostic standards and supported by history and laboratory. 42 were fatty liver, validated by clinical and other methods such as CT, MRI etc.. 34 were liver metastasis, gastric and colon primary validated by operation or pathology. 24 were hemangioma, confirmed with clinical and other examination. Additionally, 48 volunteer were employed as control.2 Image acquisition: Study were performed using aTOSHIBA SSA-370A with a 3- to 6-MHz convex transducer (PMV-375). The transmitted frequencies were 3.0 MHz, 4.2 MHz and 6.0 MHz in FI. The harmonic frequencies were 4.6 MHz, 4.8MHz and 5.0 MHz respectively. The same transducer was used for both conventional and tissue harmonic sonography, and a single switch on the console control panel was used to alternate between the two image techniques. Equipment setting such as preprocessing, postprocessing,, gain, persistence,, and space-time imaging parameters were defaulted that manufacturer's recommended and were the same for both tissue harmonic and conventional sonography examinations. Images were recorded on MO disc for analysis later. All subjects fasting 12 hours were imaged with FI in supine position or left lateral position, to freeze appropriate 2D section, setting region of interest (ROI) at near field and far field, respectively. Recording parameters in histogram.3 Image analysis and parameters calculation: 3.1 Analysis on image quality of THI and FI: after all subjects were accrued in the study, three experienced sonographers performed a separated image quality assessment to compare the two techniques. The sonographers reviewed images independently and used a subjective three-point scale to rank the quality according to the standards below: penetration, detail, and overall image quality. Penetration was defined as display of anatomic structures at the far fields. Detail wasdefined as sharpness of liver outlines and tubular fluid-filled structure. Total image quality was defined as an overall assessment encompassing spatial resolution or detail, contrast of fluid-filled structures, and absence of noise and artifacts. In the three-point grading system, the three aspects of each image were scored respectively as follow: the best was scored 2 point, the moderate was 1 point and the worst was 0 point. The average was calculated with the points obtained from the three aspects for each image. 3.2 parameters calculation: Two parameters, the MS and SD were recorded in histogram. 3.2.1 the MSs and SDs in near field and far field of THI and FI mode were measured. Paired t test and ANOVA analysis were adopted to determine the statistic difference between and in group. 3.2.2 In the diffuse liver disease group, the tissue structure coefficient of variation (CTV) was derived from MSs and SDs, calculated as below: CTV=SD/MS. 3.2.3 Three parameters of the liver tumor, signal-to-noise ratio (SNR), CTV, and specific tissuestructure coefficient of variation (CTVs) were calculated.(MS1 MS2 represent the MS of tumor and the background tissue respectively. SDl5 SD2 represent the SD of the tumor and the background tissue.) CTVs=CTV,/CTV2; (CTV, and CTV2 were the CTV of tumor and the background tissue.)4 Pathologic analysis: the excised specimen... |
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