Reproducibility of ultrasound-guided attenuation parameter (UGAP) to the noninvasive evaluation of hepatic steatosis.

The aim of this study was to identify the applicability of an ultrasound-guided attenuation parameter (UGAP) for the noninvasive assessment of hepatic steatosis in clinical practice and to compare its correlation with B-mode ultrasound (US). From May to July 2021, 63 subjects with different body mass index (BMI) grades were included in the prospective study. All of them performed UGAP measurements, under different breathing manipulations, positions, diet statuses, and operators. After that, the UGAP values were compared with the visual grades of hepatic steatosis on B-mode US using a 4-point scale method. The intraclass correlation (ICC) of the UGAP values between the two radiologists was 0.862 (p < 0.001), and the ICCs of the UGAP values on the same day and different days by radiologist A were 0.899 (p < 0.001) and 0.910 (p < 0.001), respectively. There were no significant differences in UGAP values under different breathing manipulations (p > 0.05), positions (p > 0.05), or diet statuses (p = 0.300). The UGAP values in the fasting (supine position, segment V, 1) condition among the lean (BMI < 24 kg/m2), overweight (24 kg/m2 ≤ BMI < 28 kg/m2) and obese groups (BMI ≥ 28 kg/m2) were 0.60 ± 0.12, 0.66 ± 0.14, and 0.71 ± 0.11 dB/cm/MHz, respectively, with a significant difference (p = 0.006). The correlation coefficients (Rho) between the UGAP values and the visual grades of hepatic steatosis by the two reviewers were 0.845 (p < 0.001) and 0.850 (p < 0.001), corresponding to a strong relationship. Steatosis grades by reviewer 1 (p = 0.036) and reviewer 2 (p = 0.003) were significant factors determining the UGAP values according to the multivariate linear regression analysis. UGAP demonstrated excellent intraobserver and interobserver reproducibility in the assessment of hepatic steatosis. UGAP may be a promising tool in clinical practice to predict hepatic steatosis.

Zhao Y ，Jia M ，Zhang C ，Feng X ，Chen J ，Li Q ，Zhang Y ，Xu W ，Dong Y ，Jiang Y ，Liu Y ，Huang P ... -  《Scientific Reports》

Altered probe pressure and body position increase diagnostic accuracy for men and women in detecting hepatic steatosis using quantitative ultrasound.

To evaluate the diagnostic performance of ultrasound guided attenuation parameter (UGAP) for evaluating liver fat content with different probe forces and body positions, in relation to sex, and compared with proton density fat fraction (PDFF). We prospectively enrolled a metabolic dysfunction-associated steatotic liver disease (MASLD) cohort that underwent UGAP and PDFF in the autumn of 2022. Mean UGAP values were obtained in supine and 30° left decubitus body position with normal 4 N and increased 30 N probe force. The diagnostic performance was evaluated by the area under the receiver operating characteristic curve (AUC). Among 60 individuals (mean age 52.9 years, SD 12.9; 30 men), we found the best diagnostic performance with increased probe force in 30° left decubitus position (AUC 0.90; 95% CI 0.82-0.98) with a cut-off of 0.58 dB/cm/MHz. For men, the best performance was in supine (AUC 0.91; 95% CI 0.81-1.00) with a cut-off of 0.60 dB/cm/MHz, and for women, 30° left decubitus position (AUC 0.93; 95% CI 0.83-1.00), with a cut-off 0.56 dB/cm/MHz, and increased 30 N probe force for both genders. No difference was in the mean UGAP value when altering body position. UGAP showed good to excellent intra-reproducibility (Intra-class correlation 0.872; 95% CI 0.794-0.921). UGAP provides excellent diagnostic performance to detect liver fat content in metabolic dysfunction-associated steatotic liver diseases, with good to excellent intra-reproducibility. Regardless of sex, the highest diagnostic accuracy is achieved with increased probe force with men in supine and women in 30° left decubitus position, yielding different cut-offs. The ultrasound method ultrasound-guided attenuation parameter shows excellent diagnostic accuracy and performs with good to excellent reproducibility. There is a possibility to alter body position and increase probe pressure, and different performances for men and women should be considered for the highest accuracy. • There is a possibility to alter body position when performing the ultrasound method ultrasound-guided attenuation parameter. • Increase probe pressure for the highest accuracy. • Different performances for men and women should be considered.

Byenfeldt M ，Kihlberg J ，Nasr P ，Grönlund C ，Lindam A ，Bartholomä WC ，Lundberg P ，Ekstedt M ... -  《-》

Diagnostic accuracy of ultrasound-guided attenuation parameter as a noninvasive test for steatosis in non-alcoholic fatty liver disease.

The purpose of this study was to evaluate the diagnostic accuracy of the ultrasound-guided attenuation parameter (UGAP) using the LOGEQ E10 for hepatic steatosis in non-alcoholic fatty liver disease (NAFLD) patients and directly compare UGAP with attenuation imaging (ATI) and controlled attenuation parameter (CAP). We prospectively analyzed 105 consecutive patients with NAFLD who underwent UGAP, ATI, CAP, and liver biopsy on the same day between October 2019 and April 2021. The diagnostic ability of the UGAP-determined attenuation coefficient (AC) was evaluated using receiver operating characteristic (ROC) curve analysis, and its correlation with ATI-determined AC values or CAP values was investigated. The success rate of UGAP was 100%. The median IQR/med obtained by UGAP was 4.0%, which was lower than that of ATI and CAP (P < 0.0001). The median ACs obtained by UGAP for grades S0 (control), S1, S2, and S3 were 0.590, 0.670, 0.750, and 0.845 dB/cm/MHz, respectively, demonstrating a stepwise increase with increasing hepatic steatosis severity (P < 0.0001). The areas under the ROC curve of UGAP for identifying ≥ S1, ≥ S2, and S3 were 0.890, 0.906, and 0.912, respectively, which were significantly better than the results obtained with CAP for identifying S3. Furthermore, the correlation coefficient between UGAP-AC and ATI-AC values was 0.803 (P < 0.0001), indicating a strong relationship. Our results indicate that UGAP has high diagnostic accuracy for detecting and grading hepatic steatosis in patients with NAFLD.

Kuroda H ，Abe T ，Fujiwara Y ，Nagasawa T ，Takikawa Y ... -  《-》

Ultrasound attenuation imaging: a reproducible alternative for the noninvasive quantitative assessment of hepatic steatosis in children.

Pediatric hepatic steatosis is a global public health concern, as an increasing number of children are affected by this condition. Liver biopsy is the gold standard diagnostic method; however, this procedure is invasive. Magnetic resonance imaging (MRI)-derived proton density fat fraction has been accepted as an alternative to biopsy. However, this method is limited by cost and availability. Ultrasound (US) attenuation imaging is an upcoming tool for noninvasive quantitative assessment of hepatic steatosis in children. A limited number of publications have focused on US attenuation imaging and the stages of hepatic steatosis in children. To analyze the usefulness of ultrasound attenuation imaging for the diagnosis and quantification of hepatic steatosis in children. Between July and November 2021, 174 patients were included and divided into two groups: group 1, patients with risk factors for steatosis (n = 147), and group 2, patients without risk factors for steatosis (n = 27). In all cases, age, sex, weight, body mass index (BMI), and BMI percentile were determined. B-mode US (two observers) and US attenuation imaging with attenuation coefficient acquisition (two independent sessions, two different observers) were performed in both groups. Steatosis was classified into four grades (0: absent, 1: mild, 2: moderate and 3: severe) using B-mode US. Attenuation coefficient acquisition was correlated with steatosis score according to Spearman's correlation. Attenuation coefficient acquisition measurements' interobserver agreement was assessed using intraclass correlation coefficients (ICC). All attenuation coefficient acquisition measurements were satisfactory without technical failures. The median values for group 1 for the first session were 0.64 (0.57-0.69) dB/cm/MHz and 0.64 (0.60-0.70) dB/cm/MHz for the second session. The median values for group 2 for the first session were 0.54 (0.51-0.56) dB/cm/MHz and 0.54 (0.51-0.56) dB/cm/MHz for the second. The average attenuation coefficient acquisition was 0.65 (0.59-0.69) dB/cm/MHz for group 1 and 0.54 (0.52-0.56) dB/cm/MHz for group 2. There was excellent interobserver agreement at 0.94 (95% CI 0.92-0.96). There was substantial agreement between both observers (κ = 0.77, with a P < 0.001). There was a positive correlation between ultrasound attenuation imaging and B-mode scores for both observers (r = 0.87, P < 0.001 for observer 1; r = 0.86, P < 0.001 for observer 2). Attenuation coefficient acquisition median values were significantly different for each steatosis grade (P < 0.001). In the assessment of steatosis by B-mode US, the agreement between the two observers was moderate (κ = 0.49 and κ = 0.55, respectively, with a P < 0.001 in both cases). US attenuation imaging is a promising tool for the diagnosis and follow-up of pediatric steatosis, which provides a more repeatable form of classification, especially at low levels of steatosis detectable in B-mode US.

Dardanelli EP ，Orozco ME ，Oliva V ，Lutereau JF ，Ferrari FA ，Bravo MG ，Ruvinsky S ，Roel M ，Barvosa PC ，Armeno M ，Kaplan JS ... -  《-》

Utility of Ultrasound-Guided Attenuation Parameter for Grading Steatosis With Reference to MRI-PDFF in a Large Cohort.

Ultrasound-guided attenuation parameter (UGAP) is recently developed for noninvasive evaluation of steatosis. However, reports on its usefulness in clinical practice are limited. This prospective multicenter study analyzed the diagnostic accuracy of grading steatosis with reference to magnetic resonance imaging-based proton density fat fraction (MRI-PDFF), a noninvasive method with high accuracy, in a large cohort. Altogether, 1010 patients with chronic liver disease who underwent MRI-PDFF and UGAP were recruited and prospectively enrolled from 6 Japanese liver centers. Linearity was evaluated using intraclass correlation coefficients between MRI-PDFF and UGAP values. Bias, defined as the mean difference between MRI-PDFF and UGAP values, was assessed by Bland-Altman analysis. UGAP cutoffs for pairwise MRI-PDFF-based steatosis grade were determined using area under the receiver-operating characteristic curve (AUROC) analyses. UGAP values were shown to be normally distributed. However, because PDFF values were not normally distributed, they were log-transformed (MRI-logPDFF). UGAP values significantly correlated with MRI-logPDFF (intraclass correlation coefficient = 0.768). Additionally, Bland-Altman analysis showed good agreement between MRI-logPDFF and UGAP with a mean bias of 0.0002% and a narrow range of agreement (95% confidence interval [CI], -0.015 to 0.015). The AUROCs for distinguishing steatosis grade ≥1 (MRI-PDFF ≥5.2%), ≥2 (MRI-PDFF ≥11.3%), and 3 (MRI-PDFF ≥17.1%) were 0.910 (95% CI, 0.891-0.928), 0.912 (95% CI, 0.894-0.929), and 0.894 (95% CI, 0.873-0.916), respectively. UGAP has excellent diagnostic accuracy for grading steatosis with reference to MRI-PDFF. Additionally, UGAP has good linearity and negligible bias, suggesting that UGAP has excellent technical performance characteristics that can be widely used in clinical trials and patient care. (UMIN Clinical Trials Registry, Number: UMIN000041196).

Imajo K ，Toyoda H ，Yasuda S ，Suzuki Y ，Sugimoto K ，Kuroda H ，Akita T ，Tanaka J ，Yasui Y ，Tamaki N ，Kurosaki M ，Izumi N ，Nakajima A ，Kumada T ... -  《-》