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CC BY-NC-ND 4.0 · Indian J Radiol Imaging 2016; 26(02): 231-236
DOI: 10.4103/0971-3026.184418
Head & Neck

Diffusion-weighted imaging in extracranial head and neck schwannomas: A distinctive appearance

Abanti Das
Department of Radiodiagnosis, All India Institute of Medical Sciences, New Delhi, India
,
Ashu S Bhalla
Department of Radiodiagnosis, All India Institute of Medical Sciences, New Delhi, India
,
Raju Sharma
Department of Radiodiagnosis, All India Institute of Medical Sciences, New Delhi, India
,
Atin Kumar
Department of Radiodiagnosis, All India Institute of Medical Sciences, New Delhi, India
,
Alok Thakar
Department of Otolaryngorhinology, All India Institute of Medical Sciences, New Delhi, India
,
Ankur Goyal
Department of Radiodiagnosis, All India Institute of Medical Sciences, New Delhi, India
› Author Affiliations Financial support and sponsorship Nil.
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Abstract

Purpose: To evaluate the diffusion weighted (DW) magnetic resonance imaging (MRI) features of the extracranial schwannomas of head and neck. Materials and Methods: The MRI (including DWI) of 12 patients with pathologically proven head and neck schwannomas (4 men, 8 women, with mean age of 32.6 years; age range 16–50 years) were retrospectively evaluated. Images were analyzed for signal intensity and morphology on conventional sequences followed by the qualitative evaluation of DW images (DWI) and measurement of apparent diffusion coefficient (ADC) values. Results: Majority of the tumors were located in the parapharyngeal space (8/12). All but one showed heterogeneous appearance, with 10 tumors showing scattered areas of hemorrhage. Eight out of 12 tumors showed intensely hyperintense core surrounded by intermediate signal intensity peripheral rim (reverse target sign) on T2-weighted (T2W) images. On DWI, these eight tumors showed a distinctive appearance, resembling target sign on trace DWI and reverse target on ADC map. Out of the remaining four tumors, one showed uniformly restricted diffusion whereas three showed free diffusion. Mean ADC value in the central area of free diffusion was 2.277 × 10−3 mm2/s (range of 1.790 × 10−3 to 2.605 × 10−3 mm2/s) whereas in the peripheral area was 1.117 × 10−3 mm2/s (range of 0.656 × 10−3 to 1.701 × 10−3 mm2/s). Rest of the schwannomas showing free diffusion had a mean ADC value of 1.971 × 10−3 mm2/s. Conclusion: Majority of the head and neck schwannomas showed a characteristic appearance of free diffusion in the centre and restricted diffusion in the periphery of the mass.

Keywords

Benign - diffusion weighted imaging - head and neck neoplasms - magnetic resonance imaging - schwannoma


Publication History

Article published online:
30 July 2021

© 2016. Indian Radiological Association. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).

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