Golden-Angle Radial Sparse Parallel (GRASP) MRI differentiates head & neck paragangliomas from schwannomas.

Area of Science:

• Radiology
• Oncology
• Medical Imaging

Background:

• Differentiating paragangliomas and schwannomas in the head and neck is crucial for appropriate treatment.
• Conventional MRI features can sometimes be ambiguous, necessitating advanced imaging techniques.

Purpose of the Study:

• To evaluate the efficacy of Dynamic Contrast-Enhanced MRI (DCE-MRI) using Grace Sampling (GRASP) in distinguishing between head and neck paragangliomas and schwannomas.
• To demonstrate the value of high spatiotemporal resolution DCE-MRI for improved diagnostic confidence.

Main Methods:

• Retrospective analysis of 6 patients with biopsy-proven cervical paragangliomas (n=3) and schwannomas (n=3) who underwent head and neck GRASP-MRI.
• Evaluation of conventional MRI features and lesion size.
• Postprocessing of 4D-GRASP datasets with different temporal resolutions (4.1s and 1.6s) for qualitative and semiquantitative analysis of time-intensity curves and perfusion modeling.
• Correlation of GRASP perfusion analysis with conventional imaging in an additional 5 presumed cases.

Main Results:

• 4D GRASP reconstructions (4.1s temporal resolution) showed distinct time-intensity curve patterns: type-III (rapid inflow-washout) for paragangliomas versus type-I (inflow) for schwannomas.
• Semiquantitative analysis across both temporal resolutions revealed faster wash-in, wash-out, and higher peak signal intensities in paragangliomas compared to schwannomas.
• GRASP time-intensity curves enhanced diagnostic certainty in presumed cases.

Conclusions:

• Visual classification and semiquantitative analysis of GRASP-MRI time-intensity curves are sufficient to differentiate cervical paragangliomas from schwannomas in this series.
• This technique has the potential to increase diagnostic confidence for lesions lacking typical conventional imaging features.