Contrast-enhanced ultrasound liver imaging reporting and data system: clinical validation in a prospective multinational study in North America and Europe.

BACKGROUND AND AIMS: The objective of this study is to determine the diagnostic accuracy of the American College of Radiology Contrast-Enhanced Ultrasound (CEUS) Liver Imaging Reporting and Data System LR-5 characterization for HCC diagnosis in North American or European patients. APPROACH AND RESULTS: A prospective multinational cohort study was performed from January 2018 through November 2022 at 11 academic and nonacademic centers in North America and Europe. Patients at risk for HCC with at least 1 liver observation not previously treated, identified on ultrasound (US), or multiphase CT or MRI performed as a part of standard clinical care were eligible for the study. All participants were examined with CEUS of the liver within 4 weeks of CT/MRI or tissue diagnosis to characterize up to 2 liver nodules per participant using ACR CEUS Liver Imaging Reporting and Data System. Definite HCC diagnosis on the initial CT/MRI, imaging follow-up, or histology for CT/MRI-indeterminate nodules were used as reference standards. A total of 545 nodules had confirmed reference standards in 480 patients, 73.8% were HCC, 5.5% were other malignancies, and 20.7% were nonmalignant. The specificity of CEUS LR-5 for HCC was 95.1% (95% CI 90.1%-97.7%), sensitivity 62.9% (95% CI 57.9%-67.7%), positive predictive value 97.3% (95% CI 94.5%-98.7%), and negative predictive value 47.7% (95% CI 41.7%-53.8%). In addition, benign CEUS characterization (LR-1 or LR-2) had 100% specificity and 100% positive predictive value for nonmalignant liver nodules. CONCLUSIONS: CEUS Liver Imaging Reporting and Data System provides an accurate categorization of liver nodules in participants at risk for HCC.

Sonographic evaluation of a surgically created pouch.

This manuscript focuses on a review of the normal and abnormal sonographic appearance of the surgically created pouch as part of an article series on the topic. It includes information regarding sonographic technique, normal anatomy, and commonly encounter diseases and complications.

Nodules Identified on Surveillance Ultrasound for HCC: CEUS or MRI as the Initial Test?

OBJECTIVES: Following positive surveillance ultrasound (US), magnetic resonance imaging (MRI) is recommended for further characterization. We propose contrast-enhanced ultrasound (CEUS) shows equivalent efficacy. METHODS: This prospective institutional review board approved study recruited 195 consecutive at-risk patients with a positive surveillance US. All had CEUS and MRI. Biopsy (n = 44) and follow-up are gold standard. MRI and CEUS results are classified according to liver imaging reporting and data system (LI-RADS) and patient outcome. RESULTS: As an US-based modality, CEUS is superior in confirming findings from surveillance US, correlation in 189/195 (97%) on CEUS compared to 153/195 (79%) on MRI. Within these negative MRI examinations, there are 2 hepatocellular carcinoma (HCC) and 1 cholangiocarcinoma (iCCA) diagnosed on CEUS and proven by biopsy. From 195 patients, there are 71 malignant diagnoses from all sources, including 58 LR-5 (45 on MRI and 54 on CEUS) and 13 others, including HCC outside of LR-5 category, and LR-M with biopsy proven iCCA (3 on MRI and 6 on CEUS). CEUS and MRI show concordant results in the majority of patients (146/195, 75%), including 57/146 malignant and 89/146 benign diagnoses. There are 41/57 concordant LR-5 and 6/57 concordant LR-M. When CEUS and MRI are discordant, CEUS upgraded 20 (10 biopsy-proven) from MRI LR-3/4 to CEUS LR-5 or LR-M by showing washout (WO) that MRI failed to show. Additionally, CEUS characterized time and intensity of WO and diagnosed 13/20 LR-5 by showing late and weak WO and 7 LR-M by showing fast and marked WO. CEUS is 81% sensitive and 92% specific in diagnosing malignancy. MRI is 64% sensitive and 93% specific. CONCLUSIONS: CEUS performance is at least equivalent if not superior to MRI for initial evaluation of lesions from surveillance US.

Characterization of Focal Liver Masses: A Multicenter Comparison of Contrast-Enhanced Ultrasound, Computed Tomography, and Magnetic Resonance Imaging.

OBJECTIVES: To demonstrate the usefulness of contrast-enhanced ultrasound (CEUS) for the evaluation of focal liver masses via a direct comparison to standard ultrasound and computed tomography/magnetic resonance imaging (CT/MRI). METHODS: A cohort of 214 patients with previously undiagnosed focal liver masses were included from 5 different centers. Each patient was imaged using CEUS and CT and/or MRI. Anonymized and randomized images were interpreted by 4 separate blind readers from 3 of the participating centers (2 readers for CEUS and 2 readers for CT/MRI). Readers were blinded to patient demographics and past medical history. Readers were asked to decide if the lesion was benign or malignant, provide a final diagnosis for the lesion, and provide a confidence interval. Results were compared to truth standard from pathology or expert consensus. RESULTS: In determination of malignancy, CEUS had a sensitivity of 95%, specificity of 82%, PPV of 82%, NPV of 95%, statistically better than standard ultrasound (sensitivity 82%, specificity 56%, PPV 60%, NPV 78%) with P < .01 and not statistically different from CT (sensitivity 90%, specificity 73% PPV 81%, NPV 86%) or MRI (sensitivity 85%, specificity 79%, PPV 68%, NPV 91%) with P ≥ .01. In assigning a final diagnosis, CEUS had an accuracy of 78% statistically better than standard ultrasound (46%) with P < .01 and not statistically different from CT (68%) or MRI (71%) with P > .01. CONCLUSIONS: In the evaluation of focal liver lesions, both for determination of malignancy and in accuracy of final diagnosis, CEUS performs better than standard ultrasound and at least equivalent to both CT and MRI.

RadioGraphics Update: Contrast-enhanced US Approach to the Diagnosis of Focal Liver Masses.

Editor's Note.-Articles in the RadioGraphics Update section provide current knowledge to supplement or update information found in full-length articles previously published in RadioGraphics. Authors of the previously published article provide a brief synopsis that emphasizes important new information such as technological advances, revised imaging protocols, new clinical guidelines involving imaging, or updated classification schemes. Articles in this section are published solely online and are linked to the original article.

Risk stratification of patients with nonalcoholic fatty liver disease using a case identification pathway in primary care: a cross-sectional study.

BACKGROUND: Identification of patients with nonalcoholic fatty liver disease (NAFLD) with advanced liver fibrosis in primary care remains an unmet need. Our primary objective was to implement a pathway driven by shear wave elastography (SWE) to facilitate risk stratification of patients with NAFLD within primary care and evaluate whether SWE assessment can reduce referrals of patients with NAFLD at low risk for fibrosis to hepatology. METHODS: A multidisciplinary NAFLD clinical care pathway was codeveloped by hepatologists, radiologists and primary care physicians in Calgary to provide access to SWE-based screening of patients with NAFLD risk factors in primary care. The study outcome measures were estimated NAFLD-related referrals to the hepatology service in Calgary after implementation of the NAFLD pathway and characteristics of patients with NAFLD at risk for advanced fibrosis. The NAFLD pathway was implemented in January 2018 and was made available to all primary care physicians in the Calgary Health Zone. Patients with NAFLD who had liver stiffness (SWE value ≥ 8.0 kPa) or an inconclusive assessment were referred to hepatology. A serum liver fibrosis score was also measured with the fibrosis-4 (FIB-4) index, and performance of an FIB-4 index score of 1.30 or greater to risk stratify patients with NAFLD was evaluated. Demographic, clinical and laboratory characteristics of study groups were compared. RESULTS: Between March and October 2018, 2084 patients with suspected NAFLD were evaluated. Nonalcoholic fatty liver disease was confirmed by ultrasonography in 1958 (94.1%). A majority of the cohort had elevated liver enzyme values (1028 [52.5%]) and obesity (body mass index ≥ 30) (1063/1764 [60.3%]). Most patients with NAFLD (1791 [91.5%]) had an SWE value less than 8.0 kPa and were not referred to hepatology. Sixty-seven patients (3.4%) had an SWE value of 8.0 kPa or more, and 100 (5.1%) had an inconclusive SWE; these patients were referred to hepatology. Using an FIB-4 index score cut-off of 1.30 would have led to hepatology referral of 396/1251 patients (31.6%). INTERPRETATION: Implementation of a primary care-accessible SWE pathway for patients with NAFLD facilitated fibrosis risk stratification and greatly reduced hepatology referrals. Using the FIB-4 index score alone would led to higher rates of referral of patients with NAFLD.

Acoustic Radiation Force Impulse and Conventional Ultrasound in the Prediction of Cirrhosis Complicating Fatty Liver: Does Body Mass Index Independently Alter the Results?

We investigated whether ultrasound (US) could quantify steatosis and fibrosis in non-alcoholic fatty liver disease (NAFLD). Estimates of fat by gray-scale, hepatorenal index (HRI) and fibrosis by acoustic radiation force impulse (ARFI) were made using the interquartile range (IQR)/median for ARFI quality. Biopsy was the gold standard. US fat assessment correlated with histologic grade and predicted steatosis. HRI predicted steatosis but did not improve accuracy. ARFI of good quality was highly sensitive toward severe fibrosis. The median ARFI value depended linearly on body mass index (BMI). Poor quality ARFI data had higher histologic steatosis, leading to higher mean steatosis grades in rejected data (p = 0.018). The ARFI quality cut with IQR/median >0.15 or >0.3 excluded many more patients with severe steatosis versus normal, influenced by increasing BMI. By combining the baseline US with ARFI, patients can be concurrently diagnosed for steatosis and fibrosis, two of the key pathologies of NAFLD and non-alcoholic steatohepatitis (NASH). However, severe steatosis and high BMI may falsely alter ARFI results.

Bowel Ultrasound State of the Art: Grayscale and Doppler Ultrasound, Contrast Enhancement, and Elastography in Crohn Disease.

Bowel ultrasound (US) is accurate for assessing bowel inflammation and complications in Crohn disease. Additionally, contrast-enhanced US provides a quantitative, objective measurement of inflammatory activity in inflammatory bowel disease, and shear wave elastography predicts the stiffness of bowel, an increase of which suggests less response to medical therapy, often necessitating surgery. Overall, bowel US is an excellent, safe, and repeatable choice for routine surveillance and for urgent imaging. We describe an approach to evaluating inflammatory bowel disease and review its features on standard grayscale US with Doppler imaging and show how contrast-enhanced US and shear wave elastography can distinguish between inflammatory and fibrostenotic bowel.

Role of contrast-enhanced ultrasound in evaluation of the bowel.

Contrast-enhanced ultrasound (CEUS) of the gastrointestinal tract provides vascular information helpful for characterizing masses and other pathologies in and around the bowel, similar to contrast applications in other solid organs. However, the use of microbubble contrast agents for the bowel provides additional unique contributions as it gives both subjective and objective information about mural and mesenteric blood flow, invaluable for the determination of disease activity in those many patients affected by inflammatory bowel disease (IBD). IBD is a lifelong chronic disease and has its peak age of onset in adolescence or young adult life. Today, we have moved away from treating patient's symptoms and strive instead to alter the course of disease by obtaining mucosal healing. Expensive and aggressive biologic therapies and lack of agreement of patient's symptoms with their disease activity and complications necessitate frequent imaging surveillance, which must be safe, readily available, inexpensive, and effective. Ultrasound with the benefit of contrast enhancement meets these requirements and is shown in meta-analysis to be equivalent to CT and MRI scans for these indications.

Contrast-enhanced US Approach to the Diagnosis of Focal Liver Masses.

Focal liver lesions are commonly encountered and often demonstrate nonspecific findings at initial imaging. Although most incidentally discovered liver lesions are benign, their noninvasive diagnosis is necessary, especially if they are large or atypical. Imaging characterization of focal liver lesions and exclusion of malignancy are of prime importance, particularly in high-risk populations. Contrast agent-enhanced ultrasonography of liver lesions is both accurate and reproducible for evaluation of benign and malignant liver tumors. Use of an imaging algorithm and a controlled sonographic technique, including dedicated arterial phase cine imaging and imaging every 30 seconds in the portal venous phase and the delayed (or late) phase, is essential for accurate characterization. This algorithmic analysis of focal liver lesions focuses first on the determination of malignancy by imaging the portal venous phase and the late phase; washout in these phases correlates with a malignant tumor, and sustained enhancement in these phases is suggestive that a lesion is benign. In addition, the timing and the intensity of washout differentiate hepatocellular malignancies from nonhepatocellular malignancies. Nonhepatocellular tumors demonstrate early and strong washout, whereas hepatocellular malignancies show delayed and weak washout. Subsequent analysis of dynamic real-time enhancement patterns in the arterial phase demonstrates specific enhancement patterns of common benign and malignant focal liver lesions. Hemangiomas show classic peripheral nodular enhancement, and spoke-wheel centrifugal enhancement is suggestive of focal nodular hyperplasia. Hepatic adenomas may show centripetal filling. However, arterial phase enhancement in malignancy has less specificity. Online supplemental material is available for this article. ©RSNA, 2017 •.