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Intravoxel incoherent motion diffusion-weighted imaging for discrimination of benign and malignant retropharyngeal nodes

  • Head-Neck-ENT Radiology
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Abstract

Purpose

Anatomical imaging criteria for the diagnosis of malignant head and neck nodes may not always be reliable. This study aimed to evaluate the diagnostic value of conventional diffusion-weighted imaging (DWI) and intravoxel incoherent motion (IVIM) DWI in discriminating benign and malignant metastatic retropharyngeal nodes (RPNs).

Methods

IVIM DWI using 14 b-values was performed on RPNs of 30 patients with newly diagnosed metastatic nasopharyngeal carcinoma (NPC) and 30 patients with elevated plasma Epstein-Barr virus (EBV)-DNA without NPC who were part of an EBV-based NPC screening program. Histogram measurements of the two groups were compared for pure diffusion coefficient (D), pseudo-diffusion coefficient (D*), perfusion volume fraction (f) and apparent diffusion coefficient (ADC) using the Mann-Whitney U test. Area under the curves (AUCs) of significant measurements were calculated from receiver-operating characteristics analysis and compared using the DeLong test.

Results

Compared with metastatic RPNs, benign RPNs had lower ADCmean (0.73 vs 0.82 × 10−3 mm2/s) and Dmean (0.60 vs 0.71 × 10−3 mm2/s) and a higher D*mean (35.21 vs 28.66 × 10−3 mm2/s) (all p < 0.05). There was no difference in the f measurements between the two groups (p = 0.204 to 0.301). Dmean achieved the highest AUC of 0.800, but this was not statistically better than the AUCs of the other parameters (p = 0.148 to 0.991).

Conclusion

Benign RPNs in patients with EBV-DNA showed greater restriction of diffusion compared with malignant metastatic RPNs from NPC. IVIM did not show a significant advantage over conventional DWI in discriminating benign and malignant nodes.

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Abbreviations

ADC :

Apparent diffusion coefficient

AUC:

Area under the curve

D :

Pure diffusion coefficient

D*:

Pseudo-diffusion coefficient

DWI:

Diffusion-weighted imaging

EBV:

Epstein-Barr virus

f :

Perfusion volume fraction

ICC:

Intra-class correlation coefficient

IQR:

Interquartile range

IVIM:

Intravoxel incoherent motion

MinAD:

Minimum axial diameter

NPC:

Nasopharyngeal carcinoma

NPV:

Negative predictive value

PPV:

Positive predictive value

RPNs:

Retropharyngeal nodes

SD:

Standard deviation

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Funding

The work described in this paper was supported by a grant from the Research Grants Council of the Hong Kong Special Administrative Region, China (Project No.: 14107216).

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Authors and Affiliations

  1. Department of Imaging and Interventional Radiology, Faculty of Medicine, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR

    Tiffany Y. So, Qi-Yong H. Ai, Sahrish Qamar & Ann D. King

  2. Department of Chemical Pathology, State Key Laboratory of Translational Oncology, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong SAR

    W. K. Jacky Lam & K. C. Allen Chan

  3. Department of Clinical Oncology, State Key Laboratory of Translational Oncology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR

    Darren M. C. Poon, Edwin P. Hui & Frankie K. F. Mo

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  1. Tiffany Y. So
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So, T.Y., Ai, QY.H., Lam, W.K.J. et al. Intravoxel incoherent motion diffusion-weighted imaging for discrimination of benign and malignant retropharyngeal nodes. Neuroradiology 62, 1667–1676 (2020). https://doi.org/10.1007/s00234-020-02494-w

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