Results
41 patients (30 male,
11 female,
aged 59.7 ± 12.5 years) completed the SWE examination.
Patients are categorised to HCC,
liver metastasis and control groups (Refer Fig.
2).
17 patients (29.3%) of patients did not complete the SWE examination (Refer Fig.
3).
Table 1 and 2 show the mean and maximum elasticity values for HCC,
metastasis and control group.
Fig.
4 shows the box plot for comparison of the elasticity values.
There were significant differences (p<0.05) in tissue elasticity between HCC and the control group,
as well as liver metastases with the control group (Table 1 and 2).
However,
the differences in the elasticity values between HCC and liver metastasis groups were not statistically significant.
Mean size of the HCC and metastatic lesions was 8.44 ± 4.70 and 4.56 ± 2.09 cm respectively.
There is no correlation between the lesion elasticity and the lesion size.
Mean depth of the lesions was 4.33 ± 1.68 and 3.60 ± 1.51 cm respectively for HCC and liver metastases.
Table 3 shows the mean elasticity and standard deviation (SD) within the ROIs of the liver lesions.
The lesions were categorized as homogenous when SD < 5kPa inside the ROI and heterogeneous when SD > 5kPa.
27.8% (13 nodules) of the HCC and 40% (4 nodules) of the liver metastases were noted to be heterogeneous (Refer Table 4).
However the difference in the lesion heterogeneity in the two groups was not statistically significant (p = 0.68).
Discussion
This study demonstrated a significant difference in the stiffness of the HCC and metastatic lesions as compared to the control group respectively.
The elasticity values for the HCC and metastatic lesions were slightly higher in this study as compared to a recently published study,
which reported 14.86 ± 10 kPa and 28.8 ± 16 kPa for HCC and metastases,
respectively [Guibal A 2013].
However,
both studies did not show significant difference between the HCC and metastatic lesions.
Both studies also reported no significant correlation between lesion stiffness and size.
For qualitative SWE assessment,
27.8% (13 nodules) of the HCC and 40% (4 nodules) of the liver metastases were noted to be heterogeneous.
This is in comparison with the previous study [Guibal A 2013] which reported 38.5% (10 nodules) of the HCC and 86.8% (46 nodules) of the liver metastases to be heterogeneous.
The differences could be due to the sample size as the previous study assessed a total of 26 HCC and 53 metastatic lesions from various primary tumours.