Anil Chauhan

Fatty liver disease has a high and increasing prevalence worldwide, is associated with adverse cardiovascular events and higher long-term medical costs, and may lead to liver-related morbidity and mortality. There is an urgent need for accurate, reproducible, accessible, and noninvasive techniques appropriate for detecting and quantifying liver fat in the general population and for monitoring treatment response in at-risk patients. CT may play a potential role in opportunistic screening, and MRI proton-density fat fraction provides high accuracy for liver fat quantification; however, these imaging modalities may not be suited for widespread screening and surveillance, given the high global prevalence. US, a safe and widely available modality, is well positioned as a screening and surveillance tool. Although well-established qualitative signs of liver fat perform well in moderate and severe steatosis, these signs are less reliable for grading mild steatosis and are likely unreliable for detecting subtle changes over time. New and emerging quantitative biomarkers of liver fat, such as those based on standardized measurements of attenuation, backscatter, and speed of sound, hold promise. Evolving techniques such as multiparametric modeling, radiofrequency envelope analysis, and artificial intelligence-based tools are also on the horizon. The authors discuss the societal impact of fatty liver disease, summarize the current state of liver fat quantification with CT and MRI, and describe past, currently available, and potential future US-based techniques for evaluating liver fat. For each US-based technique, they describe the concept, measurement method, advantages, and limitations. ^© RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.

We present five cases of axillary lymphadenopathy which occurred after COVID-19 vaccination and that mimicked metastasis in oncologic patients. Initial radiologic diagnosis raised concerns...

Purpose: To evaluate technical and patient‐related factors that can affect the reliability of acoustic radiation force impulse shear wave elastography (ARFI‐SWE) in morbidly obese patients.Methods: A prospective single‐center study was performed on 41 patients (32 females, 78%) presenting for preoperative evaluation for bariatric surgery. ARFI‐SWE was performed using a 6 to 1.5 MHz curved (6C1) transducer. Hepatic steatosis was mild, moderate, severe, and absent in 24.4%, 12.2%, 43.9%, and 19.5% of patients, respectively. Interquartile range/median (IQR/M) ranged from 0.05 to 2.07 (0.78 ± 0.56 m/s). Twenty patients (48.7%) had reliable measurements (IQR/M < 0.3). Shear wave velocity (SWV) values were >1.34 m/s (clinically significant fibrosis) in 25 of 41 patients (61%) and >2.2 m/s (advanced fibrosis) in 19 patients (46%).Results: Median SWV was correlated with body mass index (BMI; correlation coefficient [CC] = .37; 95% CI, 0.07‐0.61; P‐value = .03) and skin‐to‐liver capsule distance (SLD) (CC = .38; 95% CI, 0.09‐0.62; P‐value = .01). IQR/M was higher in patients with BMI > 40 (0.24 ± 0.11 vs 0.39 ± 0.25, P‐value = .031) and SLD > 3 cm (0.46 ± 0.27 vs 0.23 ± 0.08, P‐value = .001), and there was higher number of unreliable examinations among patient with SLD > 3 cm (16/23 vs 5/18, P‐value = .01).Conclusion: ARFI‐SWE is technically more challenging among patients with higher BMI and SLD, resulting in a higher number of unreliable studies, which highlights the need for further advancement of ARFI technology.