Imaging approach for evaluation of focal liver lesions

Endoscopic ultrasound-guided fine-needle aspiration in the diagnostic value of focal liver lesions: A systematic analysis of 88 cases (with video)

BACKGROUND AND AIMS

Endoscopic ultrasonography-guided fine-needle aspiration (EUS-FNA) is an important diagnostic tool for suspected parenchymal lesions in the gastrointestinal tract and adjacent organs. Our study aimed to evaluate the safety and effectiveness of EUS-FNA in focal liver lesions (FLLs).

METHOD

Data from 88 patients diagnosed with FLLs by imaging who underwent EUS-FNA from 1 January 2017 to 31 August 2022 were reviewed in our retrospective study at the Second Affiliated Hospital of Soochow University and Ruijin Hospital of the School of Medicine of Shanghai Jiao Tong University. The EUS-FNA biopsy results were compared with the final diagnosis to evaluate diagnostic value. The relevant factors were analysed to determine their influence on EUS-FNA biopsy results.

RESULTS

The 88 patients analysed in this study resulted in a final diagnosis of 86 malignant and two benign cases. The overall diagnostic accuracy of EUS-FNA in FLLs was 93.18 % (82/88; 95 % Confidence Interval [CI], 87.9-98.5), with a sensitivity, specificity, positive predictive value, and negative predictive value of 93.02 % (80/86; 95 %CI, 87.6-98.4), 100 % (2/2; 95 %CI, 100-100), 100 % (80/80; 95 %CI, 100-100), and 25 % (2/8; 95 %CI, -5-55.0), respectively. The parameters related to lesion and procedure were not significantly different between these two groups (p > 0.05). The number of puncture needles in the groups showed a statistically significant difference between multiple and single punctures (p = 0.001).

CONCLUSION

Our data revealed that EUS-FNA is a safe and reliable diagnostic method for FLLs that shows high accuracy.

Radiomics and liver: Where we are and where we are headed?

Hepatic diffuse conditions and focal liver lesions represent two of the most common scenarios to face in everyday radiological clinical practice. Thanks to the advances in technology, radiology has gained a central role in the management of patients with liver disease, especially due to its high sensitivity and specificity. Since the introduction of computed tomography (CT) and magnetic resonance imaging (MRI), radiology has been considered the non-invasive reference modality to assess and characterize liver pathologies. In recent years, clinical practice has moved forward to a quantitative approach to better evaluate and manage each patient with a more fitted approach. In this setting, radiomics has gained an important role in helping radiologists and clinicians characterize hepatic pathological entities, in managing patients, and in determining prognosis. Radiomics can extract a large amount of data from radiological images, which can be associated with different liver scenarios. Thanks to its wide applications in ultrasonography (US), CT, and MRI, different studies were focused on specific aspects related to liver diseases. Even if broadly applied, radiomics has some advantages and different pitfalls. This review aims to summarize the most important and robust studies published in the field of liver radiomics, underlying their main limitations and issues, and what they can add to the current and future clinical practice and literature.

Assessing the impact and resource implications of contrast-enhanced ultrasound on workflow of patients with incidental focal liver lesions on the UK national health service

Background

Focal liver lesions (FLL) are abnormal growths that require timely identification. Contrast-enhanced ultrasound (CEUS) is a cost-effective imaging modality for characterising FLL with similar sensitivity to computed tomography (CT) and magnetic resonance imaging (MRI). Despite being recommended by NICE, its adoption within the national health service (NHS) is limited due to low clinical demand, limited referral, and lack of knowledge.

Purpose

To evaluate the impact of CEUS on patients with incidental FLL and assess the resource implications of introducing CEUS as a diagnostic service within the NHS.

Material and methods

A patient flow review and cost-minimisation analysis were conducted. This involved a targeted literature review, NHS Trust stakeholder consultations, and development of a Microsoft Excel cost-minimisation model to explore potential value of CEUS use versus CT and MRI by episode. A scenario analysis of the base-case explored increasing CEUS use to 50% and 90%. A sensitivity analysis was performed to assess how changes in assumptions impacted the model and the resulting cost estimates.

Results

The model, comparing a world with and without CEUS, showed that current use (base-case: 5%) resulted in cost savings of £224,790/year. The sensitivity analysis indicated that regardless of changes to the assumptions, CEUS still resulted in cost savings to the NHS. By increasing CEUS use to 50% and 90%, cost savings of up to £2,247,894/year and £4,046,208/year could be achieved, respectively.

Conclusion

By standardising CEUS use for characterising FLL, substantial cost savings could be realised, whilst reducing wait times and expanding diagnostic capacity, thus preserving limited CT and MRI capacity for high-priority cases.

Ultrasound fusion imaging for improving diagnostic and therapeutic strategies of focal liver lesions: A preliminary study

PURPOSE

To assess the effect of ultrasound (US) fusion imaging on the clinical diagnostic and therapeutic strategies of focal liver lesions, which are difficult to detect or diagnose by conventional US.

METHODS

From November 2019 to June 2022, 71 patients with invisible or undiagnosed focal liver lesions who underwent fusion imaging combining US with CT or MR were included in this retrospective study. The reasons for US fusion imaging were as follows: (1) lesions that were undetectable or inconspicuous on B-mode US; (2) post-ablation lesions that could not be assessed accurately by B-mode US; (3) to evaluate whether the lesions detected by B-mode US that were consistent with those presented on MRI/CT images.

RESULTS

Of the 71 cases, 43 cases were single lesions, and 28 cases were multiple lesions. Among the 46 cases which were invisible on conventional US, the display rate of lesions using US-CT/MRI fusion imaging was 30.8%, and that combined with CEUS was 76.9%. US-guided biopsy was performed in 30 patients after the detection and localization determined by fusion imaging, with a positive rate of 73.3%. Six patients with recurrence after ablation therapy were all detected and located accurately after fusion imaging, and 4 of them successfully underwent ablation therapy again.

CONCLUSION

Fusion imaging contributes to the understanding of the anatomical relationship between lesion location and blood vessels. Additionally, fusion imaging can improve the diagnostic confidence, be helpful to guide interventional operations, and hence be conducive to clinical therapeutic strategies.

Benign Hepatic Tumors: From Incidental Imaging Finding to Clinical Management

Benign hepatic tumors (BHTs) are commonly detected as incidental finding mainly due to the frequent utilization of imaging modalities, including ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI). Rigorous clinical evaluation, with a particular focus on chronic liver disease (CLD) or risk factors for CLD, medication history, physical examination for signs of CLD, blood tests, and a review of past liver radiology constitute the initial steps in the evaluation of a new liver lesion. Further, contrast-enhanced imaging using US, CT and MRI, can be used depending on the clinical scenario and their availability. The contrast-enhanced MRI provides detailed tissue assessment while avoiding exposure to radiations, although it is scarcely available and expensive. While the liver tissue-specific protocols ensure precise diagnosis, a biopsy is recommended in selected or doubtful cases. Further, most BHTs, such as hemangiomas, are harmless and do not require special management or follow-up, the hepatic adenomas and large or atypical cases of focal nodular hyperplasia are clinically relevant and require management/follow-up. In such cases, it is favorable to have a multidisciplinary team approach, which includes hepatologist, radiologist, hepatobiliary surgeon, and pathologist. This review aims to elaborate the current understanding of BHTs, and provide a practical guidance for primary care and practitioners of family and internal medicine for the disease evaluation and management.

Dual-energy computed tomography for the detection of focal liver lesions

OBJECTIVE

To qualitatively and quantitatively explore the spectral study of focal liver lesions, comparing it with the usual polychromatic assessment with single-energy computed tomography.

MATERIAL AND METHODS

We prospectively studied 50 patients with at least one focal liver lesion who were referred for abdominal multidetector computed tomography with intravenous contrast material. The portal phase was acquired with dual energy sources. The density of the lesions and of the surrounding liver parenchyma was measured both in the baseline polychromatic acquisition and in the posterior monochromatic reconstructions at 40 keV, 70 keV, and 140 keV. Spectral curves were traced and the dual-energy indices and contrast-to-noise ratio were calculated. Lastly, the quality of the images and the detectability of the lesions were assessed qualitatively.

RESULTS

Densitometric differences between the different types of lesions (avascular and vascularized) and the liver were greater at low energy levels (left side of the spectral curve) than in the polychromatic evaluation. In the subjective assessment, the 40keV energy level had the greatest lesion detectability.

CONCLUSIONS

Monochromatic spectral study with dual-energy computed tomography provides better lesion detectability at 40keV compared to that provided by the ordinary polychromatic evaluation.

Ultrasound imaging of the liver and bile ducts - expectations of a clinician

Since diseases of the liver and bile ducts are common, a clinician is faced by the need to implement an appropriate diagnostic process. It is necessary to apply diagnostic methods that enable appropriate assessment of the most common pathologies of the liver, i.e. fibrosis, steatosis and focal lesions, as well as initial assessment of the bile ducts. These goals can be achieved using ultrasound methods based on conventional sonography, contrast-enhanced sonography and elastography. The assessment of fatty liver and bile duct dilatation using ultrasound reaches satisfactory levels of sensitivity and specificity. The usage of contrast agents enables unambiguous differentiation between benign and malignant focal lesions, frequently allowing them to be identified accurately without the assistance of other imaging modalities. Elastography has enabled reliable assessment of liver fibrosis. Its results are comparable to those of the standard method, i.e. liver biopsy.

Content-based image retrieval in radiology: analysis of variability in human perception of similarity

We aim to develop a better understanding of perception of similarity in focal computed tomography (CT) liver images to determine the feasibility of techniques for developing reference sets for training and validating content-based image retrieval systems. In an observer study, four radiologists and six nonradiologists assessed overall similarity and similarity in 5 image features in 136 pairs of focal CT liver lesions. We computed intra- and inter-reader agreements in these similarity ratings and viewed the distributions of the ratings. The readers' ratings of overall similarity and similarity in each feature primarily appeared to be bimodally distributed. Median Kappa scores for intra-reader agreement ranged from 0.57 to 0.86 in the five features and from 0.72 to 0.82 for overall similarity. Median Kappa scores for inter-reader agreement ranged from 0.24 to 0.58 in the five features and were 0.39 for overall similarity. There was no significant difference in agreement for radiologists and nonradiologists. Our results show that developing perceptual similarity reference standards is a complex task. Moderate to high inter-reader variability precludes ease of dividing up the workload of rating perceptual similarity among many readers, while low intra-reader variability may make it possible to acquire large volumes of data by asking readers to view image pairs over many sessions.

A Primer on Detecting Cirrhosis and Caring for These Patients without Causing Harm

Many people who have cirrhosis are undiagnosed. The diagnosis may not become evident until they develop multiorgan failure after an invasive procedure. Patients with cirrhosis are unusually fragile and can be easily harmed and even set into a fatal down-spiral by seemingly innocuous treatments including medications and invasive procedures. There is much confusion regarding the care of these patients. For example, what medications can be used safely to treat pain, what sedatives are safe and effective, which medications are to be avoided, what diet should be prescribed, and which invasive procedures are safe. This paper provides the author's advice regarding clues to the presence of cirrhosis and the dos and do nots in the general care of these patients, based on his 30 years of experience in a liver-failure-focused academic practice.

Consensus report of the 4th International Forum for Gadolinium-Ethoxybenzyl-Diethylenetriamine Pentaacetic Acid Magnetic Resonance Imaging

This paper reports on issues relating to the optimal use of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid magnetic resonance imaging (Gd-EOB-DTPA MR imaging) together with the generation of consensus statements from a working group meeting, which was held in Seoul, Korea (2010). Gd-EOB-DTPA has been shown to improve the detection and characterization of liver lesions, and the information provided by the hepatobiliary phase is proving particularly useful in differential diagnoses and in the characterization of small lesions (around 1-1.5 cm). Discussion also focused on advances in the role of organic anion-transporting polypeptide 8 (OATP8) transporters. Gd-EOB-DTPA is also emerging as a promising tool for functional analysis, enabling the calculation of post-surgical liver function in the remaining segments. Updates to current algorithms were also discussed.

Automated retrieval of CT images of liver lesions on the basis of image similarity: method and preliminary results

PURPOSE

To develop a system to facilitate the retrieval of radiologic images that contain similar-appearing lesions and to perform a preliminary evaluation of this system with a database of computed tomographic (CT) images of the liver and an external standard of image similarity.

MATERIALS AND METHODS

Institutional review board approval was obtained for retrospective analysis of deidentified patient images. Thereafter, 30 portal venous phase CT images of the liver exhibiting one of three types of liver lesions (13 cysts, seven hemangiomas, 10 metastases) were selected. A radiologist used a controlled lexicon and a tool developed for complete and standardized description of lesions to identify and annotate each lesion with semantic features. In addition, this software automatically computed image features on the basis of image texture and boundary sharpness. Semantic and computer-generated features were weighted and combined into a feature vector representing each image. An independent reference standard was created for pairwise image similarity. This was used in a leave-one-out cross-validation to train weights that optimized the rankings of images in the database in terms of similarity to query images. Performance was evaluated by using precision-recall curves and normalized discounted cumulative gain (NDCG), a common measure for the usefulness of information retrieval.

RESULTS

When used individually, groups of semantic, texture, and boundary features resulted in various levels of performance in retrieving relevant lesions. However, combining all features produced the best overall results. Mean precision was greater than 90% at all values of recall, and mean, best, and worst case retrieval accuracy was greater than 95%, 100%, and greater than 78%, respectively, with NDCG.

CONCLUSION

Preliminary assessment of this approach shows excellent retrieval results for three types of liver lesions visible on portal venous CT images, warranting continued development and validation in a larger and more comprehensive database.