**6. Our results**

*Patients:* Two hundred and one patients with chronic hepatitis received liver biopsy and Fi‐ broscan examination within one week after RTE procedure in the Department of Hepatolo‐ gy, Osaka City University Hospital between 2007 and 2010. Etiologies of chronic liver diseases were hepatitis C virus (CHC; n=129, 64.2 %), hepatitis B virus infection (n=13, 6.5 %), non-alcohol steatohepatitis (n=30, 14.9 %), and others (n=29, 14.4 %). Liver fibrosis was evaluated according to the METAVIR score. Table 3 shows the characteristics of the patients who received these examinations.


**Figure 2.** Receiver operating characteristic curves of each parameter obtained by RTE and Fibroscan for F0-1.

ured by Fibroscan, the *r* value did not indicate a high correlation.

Mean r=0.458 SD r=0.377

Area r=0.487

Complexity r=0.451

**Table 4.** Correlation between fibroscan and the image features of RTE

p<0.001)

and 0.84 for each of respective values (Fig 4).

Table 4 shows linear regression analysis of the values obtained by RTE compared to the liver stiffness values obtained by Fibroscan. Although simple regression analyses indicated that Mean, SD, Area, and Complexity were all significantly correlated with liver stiffness meas‐

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The area under the receiver operating characteristic curve (AUC) for stage F0-1 were 0.69, 0.65, 0.69, 0.67, and 0.87 for Mean, SD, Area, Complexity, and Fibroscan, respectively (Fig 2).The AUC for stage F0-2 were 0.79, 0.70, 0.77, 0.73, and 0.87 for Mean, SD, Area, Complexi‐ ty, and Fibroscan, respectively (Fig 3). The AUC for cirrhosis (F4) were 0.78, 0.68, 0.77, 0.76,

#### **Table 3.** Characteristics of the patients

*Results:* Histological and laparoscopical examination: 16 (8 %) patients were classified as F0, 98 (49 %) as F1, 33 (16 %) as F2, 27 (13 %) as F3, and 27 (13 %) as F4 (cirrhosis). RTE was performed successfully on all patients but Fibroscan measurements could not be obtained for 14 patients (7.0 %)because of obesity and liver atrophy. The Mean decreased in proportion to the increase of fibrosis score (Jonckheere–Terpstra test, p<0.0001). SD, Area, Complexity, and Fibroscan in‐ creased in proportion to the increase of fibrosis score (Jonckheere–Terpstra test, p< 0.0001).

**Figure 2.** Receiver operating characteristic curves of each parameter obtained by RTE and Fibroscan for F0-1.

Table 4 shows linear regression analysis of the values obtained by RTE compared to the liver stiffness values obtained by Fibroscan. Although simple regression analyses indicated that Mean, SD, Area, and Complexity were all significantly correlated with liver stiffness meas‐ ured by Fibroscan, the *r* value did not indicate a high correlation.


**Table 4.** Correlation between fibroscan and the image features of RTE

**6. Our results**

286 Liver Biopsy – Indications, Procedures, Results

who received these examinations.

*Patients:* Two hundred and one patients with chronic hepatitis received liver biopsy and Fi‐ broscan examination within one week after RTE procedure in the Department of Hepatolo‐ gy, Osaka City University Hospital between 2007 and 2010. Etiologies of chronic liver diseases were hepatitis C virus (CHC; n=129, 64.2 %), hepatitis B virus infection (n=13, 6.5 %), non-alcohol steatohepatitis (n=30, 14.9 %), and others (n=29, 14.4 %). Liver fibrosis was evaluated according to the METAVIR score. Table 3 shows the characteristics of the patients

**Sex: male/ female 89/112**

Fibrosis stage(METAVIR Score)

Etiology

BMI, body mass index.

**Table 3.** Characteristics of the patients

F0 16 F1 98 F2 33 F3 27 F4 27

HCV 129 NASH 30 HBV 13 Autoimmune hepatitis 9 Primary biliary cirrhosis 6 Others 14

*Results:* Histological and laparoscopical examination: 16 (8 %) patients were classified as F0, 98 (49 %) as F1, 33 (16 %) as F2, 27 (13 %) as F3, and 27 (13 %) as F4 (cirrhosis). RTE was performed successfully on all patients but Fibroscan measurements could not be obtained for 14 patients (7.0 %)because of obesity and liver atrophy. The Mean decreased in proportion to the increase of fibrosis score (Jonckheere–Terpstra test, p<0.0001). SD, Area, Complexity, and Fibroscan in‐ creased in proportion to the increase of fibrosis score (Jonckheere–Terpstra test, p< 0.0001).

Age 55±13 y (21-80)\* BMI (kg/m2) 22.7±3.5 (14.1-33.2)\*

> The area under the receiver operating characteristic curve (AUC) for stage F0-1 were 0.69, 0.65, 0.69, 0.67, and 0.87 for Mean, SD, Area, Complexity, and Fibroscan, respectively (Fig 2).The AUC for stage F0-2 were 0.79, 0.70, 0.77, 0.73, and 0.87 for Mean, SD, Area, Complexi‐ ty, and Fibroscan, respectively (Fig 3). The AUC for cirrhosis (F4) were 0.78, 0.68, 0.77, 0.76, and 0.84 for each of respective values (Fig 4).

**7. Further research**

ing hepatic fibrosis.

**8. Conclusion**

**Acknowledgments**

Cannon Foundation (2011-12).

cause of obesity and liver atrophy (data not shown).

bining the RTE elasticity score with shear wave propagation.

Although our results showed that RTE was inferior to Fibroscan in determining the early stage of liver fibrosis(Fig 2 and 3), Figure 4 indicated that the performance of RTE compares favorably with that of Fibroscan for detecting liver cirrhosis in patients with chronic hepati‐ tis. Unfortunately the best method for the analysis and quantification of RTE remains un‐ clear, but this may be determined by future multicenter studies using larger patient cohorts and the combination of these parameters will enable improvement of the accuracy of assess‐

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Fibroscan has been reported to have several limitations and disadvantages in evaluating pa‐ tients with obesity and ascites. In fact, in our study, we evaluated successfully all patients with RTE, while Fibroscan measurements could not be obtained for fourteen patients be‐

In the future, a combination of imaging modalities and serological parameters or of different imaging modalities will improve further the accuracy in differentiating fibrosis stages. Inter‐ estingly, Castera et al. reported that the best results were achieved by a combination of Fi‐ broscan and the Fibro Test [22]. Although ARFI, the most recent technology, Fibroscan, and MRE are all based on shear wave propagation, RTE is constructed by an original theory which is based on tissue distortion. The best diagnostic accuracy will be obtained by com‐

We have described a static elastography technique, RTE, for the "noninvasive" visual assess‐ ment of liver stiffness. Although RTE was inferior to Fibroscan in determining the early stage of liver fibrosis, the performance of RTE compares favorably with that of Fibroscan when detecting liver cirrhosis in patients with chronic liver disease. We suggest that RTE could also be used as a routine imaging method to evaluate the degree of liver fibrosis in patients with other liver diseases. Future studies of larger patient cohorts will be necessary for the validation of RTE analysis, and the combination of RTE with other clinical values in‐ cluding dynamic elastography techniques (i.e. Fibroscan, ARFI and MRE) and serum bio‐

We thank Ms. Akiko Tonomura and Mr. Junji Warabino, Hitachi AlokaMedical Co., for the technical support for RTE. Hiroyasu Morikawa was supported by a research grant from the

markers will enable improvement of the accuracy of assessing hepatic fibrosis.

**Figure 3.** Receiver operating characteristic curves of each parameter obtained by RTE and Fibroscan for F0-2.

**Figure 4.** Receiver operating characteristic curves of each parameter obtained by RTE and Fibroscan for F4.
