What’s new in Liver Imaging – November 2020

1 year ago

HCC

 

The Liver Imaging Reporting and Data System tumor-in-vein category: a systematic review and meta-analysis.

Kim DH, Choi SH, Park SH, et al. Eur Radiol. Springer; 2020;1–10.

Available from: http://link.springer.com/10.1007/s00330-020-07282-x.

Keywords: LI-RADS, MRI, CT, HCC

Clinical question:

  1. What is the underlying etiology in cases of LR-TIV?
  2. Reason for heterogeneity in reports using the LR-TIV category?

What was done: Percentages of HCC versus non-HCC were calculated from pooled meta-analytic data of cases with LR-TIV.

How was it done: Meta-analysis of 16 previous studies identified through MEDLINE and EMBASE. Among these, there were 150 cases of LR-TIV, of which 98 (65%) were due to HCC and 52 (35%) were due to non-HCC tumors .

Findings and results: Meta-analytic pooled percentages showed that 70.9% of the LR-TIV cases were due to HCC and 29.2% were due to non-HCC. Cases with hepatitis C had higher pooled percentages of HCC as the cause for LR-TIV. Interestingly, in the 6 studies where only pathological diagnosis was used as the reference standard (the other 10 studies used a combination of pathological diagnosis and imaging follow-up), the pooled percentages of HCC were lower than the average.

Conclusion: HCC was more commonly an underlying etiology for LR-TIV than non-HCC contingent upon the reference standard, geographic differences, and study design.

Implications: Any malignancy can cause tumor-in-vein, though HCC is the most commonly reported etiology. The reference standard used for diagnosis may affect the percentage of HCC and non-HCC in LR-TIV. Study design was found to be a significant factor causing report heterogeneity.

 

LI-RADS category 5 hepatocellular carcinoma: preoperative gadoxetic acid–enhanced MRI for early recurrence risk stratification after curative resection.

Wei H, Jiang H, Zheng T, et al. Eur Radiol. Springer; 2020;1–14.

Available from: http://link.springer.com/10.1007/s00330-020-07303-9.

Keywords: LI-RADS, risk stratification, Gadoxetic acid, MRI, HCC

Clinical question: What is the role of preoperative gadoxetate-enhanced MRI in the risk stratification of early recurrence after curative resection of LR-5 HCC (v2018)?

What was done: Prospective study evaluating Gadoxetic acid MRI in 103 HCC (LR-5) patients who had early recurrence (within 2 years after surgery) after resection with curative intent.

How was it done: 207 patients (Child-Pugh A)at high risk for developing HCC ( cirrhosis or chronic hepatitis B infection), who underwent gadoxetate-enhanced 3.0T MRI within 2 weeks prior to curative resection, were followed for up to 2 years. Only those with pathologically confirmed intra or extra-hepatic HCC were included. Cox ( Proportional Hazards) regression analysis was done to identify possible predictors for early recurrence.

Findings and results: 53 of 103 patients had early recurrence. MRI findings significantly associated with early recurrence included corona enhancement, peritumoral hypointensity on hepatobiliary phase, and satellite nodule. Patients were stratified into LR-5a (none of the aforementioned MR predictors), LR-5b (one predictor), or LR-5c (two or three predictors), and found to have a 2-year disease-free survival of 65%, 39%, and 6%, respectively. AFP > 400 ng/mL was also found to be a risk factor.

Conclusion: Pre-operative prediction of early disease recurrence following surgical resection of LR-5 HCC can be done using MR features that include corona enhancement, peritumoral hypointensity on hepatobiliary, and satellite nodule.

Implications: Gadoxetate-enhanced MRI findings such as corona enhancement, peritumoral hypointensity on HBP, and presence of satellite nodules could aid in the prediction of disease-free survival.

 

LIVER IMAGING TECHNIQUES

 

On the dependence of the cardiac motion artifact on the breathing cycle in liver diffusion-weighted imaging.

Riexinger A, Laun FB, Bickelhaupt S, et al. Baltzer PAT, editor. PLoS One. Public Library of Science; 2020;15(10):e0239743.

Available from: https://dx.plos.org/10.1371/journal.pone.0239743.

Keywords: MRI, motion artifact, DWI

Clinical question: Can diffusion weighted imaging obtained in inspiration reduce cardiac motion artifact over the left hepatic lobe?

What was done: Prospective comparative study of cardiac motion artifact on the MRI DWI scans obtained in inspiration and expiration in 43 patients with known or suspected focal liver lesions.

How it was done: All patients underwent breath hold acquisition on a 1.5T scanner. DWI sequences were obtained for b=50 s/mm2 and 800 s/mm2 with patient breath-hold at inspiration and at expiration. Qualitative analysis of sequences using a Likert scale was performed by 2 readers. Normalized signal was calculated over the left hepatic lobe at both b-values for each patient’s DWI sequences by drawing a region of interest. The Wilcoxon signed-rank test was used for quantitative analysis between inspiration and expiration for each patient.

Findings and Results: Normalized signal in inspiration was slightly higher than in expiration without any statistical significance. Qualitative evaluation showed no differences.

Conclusions: No significant difference in pulsation artifact over the left hepatic lobe on DWI sequences during inspiration when compared to expiration.

Implications: While patient breath-hold during DWI of the liver may reduce cardiac motion artifact, there is no significant benefit to performing DWI of the liver during inspiration versus expiration.

 

Staging of Liver Fibrosis by Means of Semiautomatic Measurement of Liver Surface Nodularity in MRI.

Kim SW, Kim YR, Choi KH, et al. Am J Roentgenol. American Roentgen Ray Society; 2020;215(3):624–630

Available from: https://www.ajronline.org/doi/10.2214/AJR.19.22041.

Keywords: MRI, liver fibrosis, semiautomatic

Clinical question: What is the accuracy of a semiautomatic method of measuring liver surface nodularity (LSN) on contrast-enhanced MRI for staging of liver fibrosis?

What was done: Semiautomated LSN quantification software was developed and evaluated for accuracy against the calculated Metavir score.

How was it done: Retrospective study of 132 patients who had undergone gadoxetate-enhanced liver MRI 6 months before or after biopsy with histopathology for chronic liver disease staging. All patients also had AST and platelet serum levels and a fibrosis-4 index.

Findings and results: The LSN score and Metavir score had high correlation (Spearman coefficient 0.713), with AUCs for LSN equal to 0.93, 0.98, and 0.83 for F0-F1 vs F2-F4, F0-F2 vs F3-F4, and F0-F3 vs F4, respectively.

Conclusion: The LSN score calculated semiautomatically based on the algorithm developed by the authors has high accuracy and correlates with the pathologic fibrosis stage.

Implications: The potential ability to calculate LSN based on MRI features semiautomatically may prove a viable noninvasive method for staging of liver fibrosis.

 

LIVER: MISCELLANEOUS

 

MRI Findings of Liver Parenchyma Peripheral to Colorectal Liver Metastasis: A Potential Predictor of Long-term Prognosis.

Nakai Y, Gonoi W, Kurokawa R, et al. Radiology. Radiological Society of North America ; 2020;202367.

Available from: http://pubs.rsna.org/doi/10.1148/radiol.2020202367.

Keywords: MRI, colorectal metastasis, prognosis

Clinical question: Can we predict long-term prognosis using imaging findings within the liver parenchyma peripheral to colorectal liver metastases (CRLMs) using gadoxetate-enhanced MRI?

What was done: The relationship between MRI findings in the liver parenchyma peripheral to CRLMs and pathologic vessel as well as bile duct invasion was assessed.

How was it done: Retrospective study of 106 patients who underwent Gadoxetic acid enhanced MRI before curative surgery for CRLM without neoadjuvant chemotherapy. 3 abdominal radiologists evaluated early enhancement, reduced contrast uptake, and bile duct dilatation peripheral to the CRLMs on MRI. All tumor specimens were reevaluated for invasion of surrounding veins and bile ducts. Cox proportional hazard model and Bayesian information criterion were used to identify predictors of recurrence-free survival and overall survival.

Findings and results: 148 CRLMs in 106 patients were evaluated. Bile duct dilatation peripheral to the tumor was associated with pathologic portal vein and bile duct invasion as well as poor recurrence-free and overall survival. A combination of early enhancement, reduced gadoxetic acid uptake, and bile duct dilatation peripheral to the tumor was predictive of poor overall survival.

Conclusions/Implications: MRI findings at the periphery of the CRLMs were predictors of long-term prognosis after curative surgery.

References
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