Introduction
The aim of this study was to evaluate and to establish cut-off values for two new quantitative ultrasound (QUS) parameters, TSI (tissue scatter-distribution imaging) and TAI (tissue attenuation imaging) in early diagnosis of liver steatosis (LS), as compared to controlled attenuation parameter (CAP).
Aims & Methods
A prospective study was conducted in which LS was assessed in the same session by QUS (Samsung Medison RS85,CA1-7A probe) and CAP (FibroScan Compact M530, M/XL probes). Reliable measurements were defined for CAP the median value of 10 measurements with IQR/M<0.3, and for QUS, five consecutive measurements of TAI and TSI acquired by a color-coded map. TAI and TSI were automatically calculated and considered reliable when reliability index, R2>0.6. The CAP cut-off value used for the whole cohort for at least mild steatosis (S1) were 248 dB/m[1]; for ALD (alcoholic liver disease) cohort, 268 dB/mm[2]; for NAFLD(non-alcoholic liver disease) cohort 294dB/m[2]. Demographic and health related datas were recorded.
Results
A total of 285 patients, with a mean age of 56.1±12.4, 114 female and 171 male, were included in the study. According to aetiology, 164 (57.5%) patients had NAFLD, 61(21.4%) ALD, and 60 (21.1%) were other etiologies (viral, cardiac, autoimmune). The obtained TSI and TAI cut-off values for the diagnosis of at least mild steatosis (S1) are presented in Table 1.
Table 1. Cut-off values of TAI and TSI for S1
| Variable | Overall | NAFLD | ALD |
| TSI | S1 | >96.2
AUC=0.74,p<0.0001, Se=87.9%,Sp=53.0%; | >96.5
AUC=0.73, p<0.0001, Se=90.9%, Sp=47.9%; | >94.9
AUC=0.70, p=0.003 Se=72.9%,Sp=75.0%; |
| TAI | S1 | >0.73
AUC=0.82,p<0.0001, Se=78.3%,Sp=71.6%; | >0.75
AUC=0.81, p<0.0001, Se=57.5%, Sp=90.8%; | >0.66
AUC=0.74, p<0.0001, Se=84.8%,Sp=57.1%; |
There were no differences between the performance of TAI and TSI according to the DeLong test,
p=0.18 and
p=0.24. A strong direct correlation was observed between TAI and CAP r=0.701, moderate between TSI and CAP r=0.56 for the all cohort, but for NAFLD and ALD subgroups moderate correlations were found between TAI and CAP r=0.66, and r=0.66 respectively and TSI and CAP r=0.56 and 0.66, respectively.
In univariate regression analysis, the factors associated with TSI were hypertension, Diabettes mellitus(DM), and obesity, and all p-values were <0.0001, but in multivariate analysis, only hypertension(p=0.001) and obesity(p=0.0005) were associated. For TAI, in univariate analysis, the same factors: hypertension(p=0.004), obesity(p=0.0006) and DM (p=0.002) were associated, but in multivariate analysis, DM was the only factor associated,
p=0.02. Age and gender were not correlated with any method, TSI or TAI.
Conclusion
TAI and TSI are feasible non-invasive methods for screening and diagnosis of liver steatosis, with good accuracy. Patients with NAFLD presented highest cut-off values, probably by the presence of DM and obesity, conditions independently associated with TAI and TSI values.
References
1.Karlas T, Petroff D, Sasso M, Fan JG, Mi YQ, de Lédinghen Vet al. Individual patient data meta-analysis of controlled attenuation parameter (CAP) technology for assessing steatosis. J Hepatol. 2017 May;66(5):1022-1030. doi: 10.1016/j.jhep.2016.12.022. Epub 2016 Dec 28. PMID: 28039099.
2. Petroff D, Blank V, Newsome PN, Shalimar, Voican CS, Thiele M, et al. Assessment of hepatic steatosis by controlled attenuation parameter using the M and XL probes: an individual patient data meta-analysis. Lancet Gastroenterol Hepatol. 2021 Mar;6(3):185-198. doi: 10.1016/S2468-1253(20)30357-5. Epub 2021 Jan 16. PMID: 33460567.