The role of apparent diffusion coefficient values in characterization of solid focal liver lesions: a prospective and comparative clinical study

Identification of MRI features associated with injury type, severity, and prognosis in drug-induced liver injury

OBJECTIVES

To identify magnetic resonance imaging (MRI) features associated with injury type, severity, and liver transplantation (LT)/liver-related death (LRD) in drug-induced liver injury (DILI).

METHODS

The eligible DILI patients (2016 to 2020) who underwent contrast abdominal MRI within 3 months of onset were retrospectively analysed at Beijing Friendship Hospital, Capital Medical University. The MRI features independently associated with severity and prognosis were identified by backwards logistic regression. Unadjusted odds ratios (ORs) and 95% confidence intervals (CIs) are given.

RESULTS

The median age of 180 patients was 55.5 years, with 126 (70.0%) women. The injury types included hepatocellular (135 cases, 75.0%), mixed (23, 12.8%), and cholestatic (22, 12.2%). The proportion of periportal oedema in patients with hepatocellular and mixed injury was significantly higher than that in cholestatic injury (62.2%, 47.8% vs. 18.2%, p < 0.001). For severity, 157 (87.2%) patients had mild to moderate injury, and 23 (12.8%) had severe to fatal/LT. Irregularity of the liver surface (6.56 (95% CI, 1.27-22.84)), transient hepatic attenuation difference (THAD) (3.27 (95% CI, 1.14-9.36)), and splenomegaly (5.86 (95% CI, 1.96-17.53)) were independently associated with severity. Eight (4.4%) patients died/underwent LT. THAD (8.89 (95% CI, 1.35-58.43)), and ascites (64.63 (95% CI, 6.93-602.40)) were independently associated with LT/LRD. The prediction of the new model employing THAD and ascites for LT/LRD within 1 year was 0.959 (95% CI, 0.917-1.000).

CONCLUSIONS

Periportal oedema was associated with the type of injury. Irregularity of the liver surface, THAD, and splenomegaly were associated with severity. THAD and ascites may have potential clinical utility in predicting LT/LRD outcomes within 1 year.

KEY POINTS

• Contrast abdominal magnetic resonance imaging features can help clinicians evaluate the type of injury, severity, and poor prognosis of drug-induced liver injury. • Transient hepatic attenuation difference and ascites have potential clinical utility in the prediction of the poor prognosis of liver transplantation/liver-related death. • The new model predicting poor prognosis has a relatively high sensitivity of 0.875 and a high specificity of 0.919.

Diagnostic accuracy of apparent diffusion coefficient (ADC) value in differentiating malignant from benign solid liver lesions: a systematic review and meta-analysis

OBJECTIVES

We undertook a systematic review and meta-analysis of the diagnostic performance of mean apparent diffusion coefficient (ADC) values derived by diffusion-weighted (DW)-MRI in the characterization of solid benign and malignant liver lesions, and to assess their value in discriminating these lesions in daily routine practice.

METHODS

A systematic review of PubMed, Embase, Scopus, and Web of Science was conducted to retrieve studies that used ADC values for differentiating solid benign/dysplastic nodules and malignant liver lesions. A bivariate random-effects model with pooled sensitivity and specificity values with 95% CI (confidence interval) was used. This meta-analysis was performed on the per-lesion basis. Summary receiver operating characteristic (SROC) plot and area under curve (AUC) were created.

RESULTS

A total of 14 original articles were retrieved. The combined (95% CI) sensitivity and specificity of mean ADC values for differentiating solid benign from malignant lesions were 78% (67-86%) and 74% (64-81%), respectively. The pooled (95% CI) positive and negative LRs were respectively 3 (2.3-3.8) and 0.3 (0.21-0.43). The DOR (95% CI) was 10 (7-15). The AUC (95% CI) of the SROC plot was 82% (78-85%). Reporting bias was negligible (p value of regression test = 0.36). Mean size of malignant lesions and breathing pattern of MRI were found to be sources of heterogeneity of pooled sensitivity.

CONCLUSION

ADC measurement independently may not be an optimal diagnostic imaging method for differentiating solid malignant from solid benign hepatic lesions. The meta-analysis showed that ADC measurement had moderate diagnostic accuracy for characterizing solid liver lesions. Further prospective and comparative studies with pre-specified ADC thresholds could be performed to investigate the best MRI protocol and ADC threshold for characterizing solid liver lesions.

ADVANCES IN KNOWLEDGE

ADC measurement by DW-MRI does not have a good diagnostic performance to differentiate solid malignant from solid benign lesions. Therefore, we suggest not using ADC values in clinical practice to evaluate solid liver lesions.

ACR Appropriateness Criteria® Liver Lesion-Initial Characterization

Incidental liver masses are commonly identified on imaging performed for other indications. Since the prevalence of benign focal liver lesions in adults is high, even in patients with primary malignancy, accurate characterization of incidentally detected lesions is of paramount clinical importance. This document reviews utilization of various imaging modalities for characterization of incidentally detected liver lesions, discussed in the context of several clinical scenarios. For each clinical scenario, a summary of current evidence supporting the use of a given diagnostic modality is reported. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Genomics Education in the Era of Personal Genomics: Academic, Professional, and Public Considerations

Since the completion of the Human Genome Project in 2003, genomic sequencing has become a prominent tool used by diverse disciplines in modern science. In the past 20 years, the cost of genomic sequencing has decreased exponentially, making it affordable and accessible. Bioinformatic and biological studies have produced significant scientific breakthroughs using the wealth of genomic information now available. Alongside the scientific benefit of genomics, companies offer direct-to-consumer genetic testing which provide health, trait, and ancestry information to the public. A key area that must be addressed is education about what conclusions can be made from this genomic information and integrating genomic education with foundational genetic principles already taught in academic settings. The promise of personal genomics providing disease treatment is exciting, but many challenges remain to validate genomic predictions and diagnostic correlations. Ethical and societal concerns must also be addressed regarding how personal genomic information is used. This genomics revolution provides a powerful opportunity to educate students, clinicians, and the public on scientific and ethical issues in a personal way to increase learning. In this review, we discuss the influence of personal genomics in society and focus on the importance and benefits of genomics education in the classroom, clinics, and the public and explore the potential consequences of personal genomic education.

Altered small-world, functional brain networks in patients with lower back pain

In this study, we aimed to investigate the functional network changes that occur in patients with lower back pain (LBP). We also investigated the link between LBP and the small-world properties of functional networks within the brain. Functional MRI (fMRI) was performed on 20 individuals with LBP and 17 age and gender-matched normal controls during the resting state. The severity of the pain in the individuals with LBP ranged from 5 to 8 on a 0-10 scale, with 0 indicating no pain. Network-based statistics were performed to investigate the differences between the brain networks of individuals with LBP and those of normal controls. Several small-world parameters of brain networks were calculated, including the clustering coefficient, characteristic path length, local efficiency, and global efficiency. These criteria reflect the overall network efficiency. The brain networks in the individuals with LBP due to herniation of a lumbar disc demonstrated a significantly longer characteristic path length as well as a lower clustering coefficient, global efficiency, and local efficiency compared to those in control subjects. We found that LBP patients tended to have unstable and inefficient brain networks when compared with healthy controls. In addition, LBP individuals showed significantly decreased functional connectivity in the anterior cingulate cortex, middle cingulate cortex, post cingulate cortex, inferior frontal gyrus, middle temporal gyrus, occipital gyrus, postcentral gyrus, precentral gyrus, supplementary motor area, thalamus, fusiform, caudate, and cerebellum. We believe that these regions may be involved in the pathophysiology of lower back pain.

Simultaneous quantification of hepatic MRI-PDFF and R2* in a rabbit model with nonalcoholic fatty liver disease

Quantification of hepatic fat and iron content is important for early detection and monitoring of nonalcoholic fatty liver disease (NAFLD) patients. This study evaluated quantification efficiency of hepatic proton density fat fraction (PDFF) by MRI using NAFLD rabbits. R2* was also measured to investigate whether it correlates with fat levels in NAFLD. NAFLD rabbit model was successfully established by high fat and cholesterol diet. Rabbits underwent MRI examination for fat and iron analyses, compared with liver histological findings. MR examinations were performed on a 3.0T MR system using multi-echo 3D gradient recalled echo (GRE) sequence. MRI-PDFF showed significant differences between different steatosis grades with medians of 3.72% (normal), 5.43% (mild), 9.11% (moderate) and 11.17% (severe), whereas this was not observed in R2*. Close correlation between MRI-PDFF and histological steatosis was observed (r=0.78, P=0.000). Hepatic iron deposit was not found in any rabbits. There was no correlation between R2* and either liver MRI-PDFF or histological steatosis. MR measuring MRI-PDFF and R2* simultaneously provides promising quantification of steatosis and iron. Rabbit NAFLD model confirmed accuracy of MRI-PDFF for liver fat quantification. R2* measurement and relationship between fat and iron of NAFLD liver need further experimental investigation.

Assessment of different mathematical models for diffusion-weighted imaging as quantitative biomarkers for differentiating benign from malignant solid hepatic lesions

To quantitatively compare the monoexponential, biexponential, and stretched‐exponential diffusion‐weighted imaging (DWI) models in differentiating benign from malignant solid hepatic lesions. The institutional review board approved this retrospective study and waived the informed consent requirement. A total of 188 patients with 288 hepatic lesions included 202 malignant lesions and 86 benign lesions were assessed (confirmed by pathology or clinical follow‐up for 6 months). All patients underwent hepatic 3.0‐T MRI, including multi‐b DWI that used 12 b values. The ADC, D_p, D_t, perfusion fraction (f_p), α, and DDC values for normal liver, benign liver lesions, and malignant liver lesions were calculated. Independent sample t tests were used for comparisons. The diagnostic performance of the parameters was evaluated using ROC analysis. The AUC value for each model was also calculated. The value of D_p was significantly lower in benign lesions than in normal hepatic parenchyma while others were significantly higher (P < .001). Whereas Values of D_t and α in malignant hepatic lesions were significantly higher than in normal hepatic parenchyma (P < .001), and the D_p value was significantly lower (P < .001). Values of ADC, f_p, DDC, and α for malignant hepatic lesions were significantly lower than those for benign hepatic lesions (P < .001). ROC analysis showed that the diagnostic value of the biexponential model of normal hepatic parenchyma vs benign hepatic lesions and normal hepatic parenchyma vs malignant hepatic lesions was high (0.946 and 0.876, respectively). In the differential diagnosis of benign and malignant hepatic lesions, DDC had the highest AUC value (0.819). The biexponential and stretched‐exponential DWI may provide additional information and improve the differential diagnosis of benign and malignant hepatic lesions compared with the monoexponential DWI.