DCE-MRI plus DWI-MRI can accurately distinguish head and neck paraganglioma from schwannoma
New Delhi, India: The use of DCE-MRI in addition to DWI-MRI can help in accurately differentiating head and neck paragangliomas (HNPGL) from schwannoma, finds a recent study in the journal Head & Neck. This may do away with the need for additional imaging and preoperative biopsy in most cases.
HNPGLs and schwannomas (HNSs) are common tumors originating in carotid space and jugular fossa and can be difficult to diagnose. Differentiation between the two becomes important from a clinico-radiological perspective as the prognosis and therapeutic strategy differ according to the type of lesion.
Morphological assessment with conventional magnetic resonance imaging (MRI) sequences has limited specificity to distinguish between paragangliomas and schwannomas. The use of dynamic contrastâenhanced (DCE)âMRI to assess the differences in microvascular properties through pharmacokinetic parameters can provide additional information to aid in this differentiation.
Smita Manchanda, All India Institute of Medical Sciences, New Delhi, India, and colleagues hypothesized that DCE-MR imaging parameters obtained via quantitative and semi-quantitative methods can be used to characterize these masses.
For this purpose, the researchers performed a prospective study on MR characterization of neck masses between January 2017 and March 2019, out of which 40 patients with (HNPGLs) (33 lesions) and schwannomas (15 lesions) were included in this analysis.
MR perfusion using dynamic axial T1WI fat-suppressed fast spoiled gradient recalled sequence with parallel imaging was performed in all the patients, in addition to singleâshot turbo spinâecho axial diffusion-weighted imaging (DWI) and routine MRI. The ROIâbased method was used to obtain signalâtime curves, permeability measurements, and mean apparent diffusion coefficient (ADC) to differentiate paragangliomas from schwannomas.
Statistical analysis was done to assess the significance and establish a cutoff to distinguish between the two entities. The available images of DOTANOC PET/CT (34 lesions) were analyzed retrospectively. Correlations between the perfusion, diffusion and molecular PET/CT parameters were done.
Key findings of the study include:
- Paragangliomas had a higher washâin rate, washâout rate, Ktrans, Kep, and Vp; while schwannomas had a higher relative enhancement, time to peak, time of onset, brevity of enhancement, and Ve.
- Among the perfusion parameters, Kep (area under curve (AUC) 0.994) and Vp (AUC 0.992) were found to have the highest diagnostic value.
- In diffusionâweighted imaging, paragangliomas had a lower mean ADC compared to schwannomas.
- The SUVmax and SUVmean were significantly associated with Ktrans, Kep, and Vp in paragangliomas.
"DCEâMRI in addition to DWIâMRI can accurately distinguish HNPGL from schwannoma and may replace the need for any additional imaging and preoperative biopsy in most cases," wrote the authors.
Reference:
The study titled, "Dynamic contrastâenhanced magnetic resonance imaging for differentiating head and neck paraganglioma and schwannoma," is published in the journal Head & Neck.
DOI: https://onlinelibrary.wiley.com/doi/10.1002/hed.26732
