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R2* value derived from multi-echo Dixon technique can aid discrimination between benign and malignant focal liver lesions
Guangzi Shi1, Hong Chen1, Weike Zeng1, Mengzhu Wang2, and Jun Shen1
1Radiology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China, 2Department of MR Scientific Marketing, Siemens Healthineers, Guangzhou, China
1Radiology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China, 2Department of MR Scientific Marketing, Siemens Healthineers, Guangzhou, China
Synopsis
R2* derived from multi-echo Dixon imaging is a potential biomarker to differentiate malignant from benign FFLs. R2* value of malignant FLLs was significantly higher than that of the benign FLLs. The multi-echo Dixon sequence is easy to perform and required only a single breath-hold of 16 s to image the entire liver, which holds a good potential for clinical application.
Introduction
Clinically, once a focal liver lesion (FLL) is identified, it is essential to distinguish between benign and malignant lesions, as this differentiation determines the individual’s prognosis and subsequent treatment strategy[1]. R2* estimation reflects the paramagnetism of the tumor tissue[2,3], which may be used to differentiate between benign and malignant liver lesions when the contrast agents is contraindicated.To investigate whether R2* derived from multi-echo Dixon imaging can aid differentiating benign from malignant focal liver lesions (FLLs) and the impact of 2D region of interest (2D-ROI) and volume of interest (VOI) on the outcomes.Methods
We retrospectively enrolled 73 patients with 108 benign or malignant FLLs. All patients underwent conventional abdominal magnetic resonance imaging and multi-echo Dixon imaging. Two radiologists independently measured the mean R2* values of lesions using 2D-ROI and VOI approaches. The Bland–Altman plot was used to determine the interobserver agreement between R2* measurements. Intraclass correlation coefficient (ICC) was used to determine the reliability between the two readers. Mean R2* values were compared between benign and malignant FFLs using the nonparametric Mann–Whitney test. Receiver Operating Characteristic curve analysis was used to determine the diagnostic performance of R2* in differentiation between benign and malignant FFLs. We compared the diagnostic performance of R2* measured by 2D-ROI and VOI approaches.Results
The study included 30 benign and 78 malignant FLLs. The interobserver reproducibility of R2* measurements was excellent for the 2D-ROI (ICC = 0.994) and VOI (ICC = 0.998) methods. Bland–Altman analysis also demonstrated excellent agreement. Mean R2* was significantly higher for malignant than benign FFLs as measured by 2D-ROI (P < 0.001) and VOI (P < 0.001). The AUC of R2* measured by 2D-ROI was 0.884 at a cut-off of 25.2/s, with a sensitivity of 84.6% and specificity of 80.0% for differentiating benign from malignant FFLs. R2* measured by VOI yielded an area under the curve (AUC) of 0.875 at a cut-off of 26.7/s in distinguishing benign from malignant FFLs, with a sensitivity of 85.9% and specificity of 76.7%. The AUCs of R2* were not significantly different between the 2D-ROI and VOI methods.Conclusion
R2* derived from multi-echo Dixon imaging whether by 2D-ROI or VOI can aid in differentiation between benign and malignant FLLs.Acknowledgements
No acknowledgement found.References
1 Dong Y, Zhang XL, Mao F, Huang BJ, Si Q, Wang WP. Contrast-enhanced ultrasound features of histologically proven small (≤20 mm) liver metastases. Scand J Gastroenterol 2017; 52: 23-28
2 Schmeel FC, Luetkens JA, Feißt A, Enkirch SJ, Endler CH, Wagenhäuser PJ, Schmeel LC, Träber F, Schild HH, Kukuk GM. Quantitative evaluation of T2* relaxation times for the differentiation of acute benign and malignant vertebral body fractures. Eur J Radiol 2018; 108: 59-65
3 Liu M, Guo X, Wang S, Jin M, Wang Y, Li J, Liu J. BOLD-MRI of breast invasive ductal carcinoma: correlation of R2* value and the expression of HIF-1α. Eur Radiol 2013; 23: 3221-3227
Figures
Figure
1. 2D region of
interest (2D-ROI) and volume of interest (VOI). T2-weighted imaging (T2WI) (A)
and arterial phase contrast-enhanced T1-weighted imaging (T1WI) (B), and R2*
map (C) show liver metastasis (yellow line) confirmed by histology in a
59-year-old woman with lung cancer. T2WI (E) and arterial phase
contrast-enhanced T1WI (F), and R2* map (G) show a live hemangioma (yellow
line) in in a 59-year-old woman. (D) 2D-ROI was drawn on the section showing
the maximal tumor dimension. (H) VOI was placed covering the
entire tumor volume on R2* map.
Figure 2. Bland–Altman plots showed
interobserver variability in 2D-ROI (A) and VOI (B) measurements. The
differences between the two readers using the two different ROI positioning
methods were small.
Figure
3. R2* values of malignant group and benign group
measured by using 2D region of interest (2D-ROI) (A) and volume of interest
(VOI) (B) methods. Data are shown as mean ±
standard deviation. Mean R2* values in malignant group were significantly higher than in the
benign group by 2D-ROI (P < 0.001) and
VOI (P < 0.001) measurements.
Figure
4. Receiver operating characteristic curve analysis of
the two positioning methods in differentiating
between malignant group and benign group. 2D region of interest (2D-ROI) and
volume of interest (VOI) methods yielded the similar results.