Current whole-body MRI applications in the neurofibromatoses

Abstract

Objectives: The Response Evaluation in Neurofibromatosis and Schwannomatosis (REiNS) International Collaboration Whole-Body MRI (WB-MRI) Working Group reviewed the existing literature on WB-MRI, an emerging technology for assessing disease in patients with neurofibromatosis type 1 (NF1), neurofibromatosis type 2 (NF2), and schwannomatosis (SWN), to recommend optimal image acquisition and analysis methods to enable WB-MRI as an endpoint in NF clinical trials.Methods: A systematic process was used to review all published data about WB-MRI in NF syndromes to assess diagnostic accuracy, feasibility and reproducibility, and data about specific techniques for assessment of tumor burden, characterization of neoplasms, and response to therapy.Results: WB-MRI at 1.5T or 3.0T is feasible for image acquisition. Short tau inversion recovery (STIR) sequence is used in all investigations to date, suggesting consensus about the utility of this sequence for detection of WB tumor burden in people with NF. There are insufficient data to support a consensus statement about the optimal imaging planes (axial vs coronal) or 2D vs 3D approaches. Functional imaging, although used in some NF studies, has not been systematically applied or evaluated. There are no comparative studies between regional vs WB-MRI or evaluations of WB-MRI reproducibility.Conclusions: WB-MRI is feasible for identifying tumors using both 1.5T and 3.0T systems. The STIR sequence is a core sequence. Additional investigation is needed to define the optimal approach for volumetric analysis, the reproducibility of WB-MRI in NF, and the diagnostic performance of WB-MRI vs regional MRI. Neurology ® 2016;87 (Suppl 1):S31-S39 GLOSSARY ADC 5 apparent diffusion coefficient; DWI 5 diffusion-weighted imaging; FDG 5 fluorodeoxyglucose; MPR 5 multiplanar reformation; NF1 5 neurofibromatosis type 1; NF2 5 neurofibromatosis type 2; PNST 5 peripheral nerve sheath tumors; REiNS 5 Response Evaluation in Neurofibromatosis and Schwannomatosis; SNR 5 signal to noise ratio; STIR 5 short tau inversion recovery; SWN 5 schwannomatosis; WB-MRI 5 whole-body MRI.Whole-body MRI (WB-MRI) allows imaging of a large volume of the body in a single image acquisition session. It has been extensively investigated for the detection and staging of visceral and osseous tumors [1][2][3][4][5][6] and is well-suited to tumor syndromes including neurofibromatosis type 1 (NF1), neurofibromatosis type 2 (NF2), and schwannomatosis (SWN), 7-9 as these patients often have a high burden of tumors as well as large tumors that cross anatomic planes (figure). WB-MRI has been used to evaluate tumor burden and to characterize neoplasms in patients with NF syndromes [10][11][12][13][14][15][16][17][18][19][20][21][22][23] and is being used in some clinical trials to evaluate response to therapy (NCT01207687). A uniform image acquisition protocol and interpretation method would enable WB-MRI to be used as a key endpoint to assess tumor treatment response in multicenter clinical trials for NF-associated perip...

Longitudinal phenotype development in a minipig model of neurofibromatosis type 1

“…The series of imaging protocols utilized for this study were guided by recommendations from the REiNS International Collaboration which indicates that MR imaging acquisition should be optimized for tumor type/ location and recommends both whole-body imaging and the STIR protocol for visualization of peripheral nerve sheath tumors 48,49 . However, it was noted in Dombi et al that some clinically relevant tumors may not have good tissue definition on MR imaging with the accompanying Fig.…”

“…Four separate protocols were used for imaging: head, whole body, spine, and targeted. The developed protocols drew from whole-body screening recommendations and typical clinical practice 48,49 . The targeted protocol was used only when an unexpected or abnormal finding was identified during one of the prior three protocols.…”

Diffusion-weighted imaging and diffusion tensor imaging as adjuncts to conventional MRI for the diagnosis and management of peripheral nerve sheath tumors: current perspectives and future directions

“…It is important to consider the usefulness of DWI given evidence in the literature that a low ADC area should be re-biopsied if the initial biopsy result is negative for malignancy or is inconclusive. Furthermore, whole body MRI with DWI is an excellent screening technique to detect potentially malignant lesions which show worrisome features, such as heterogeneity on T2W or STIR imaging and/or exhibit diffusion restriction [5,12].…”

“…Confirmation of a neurogenic lesion limits the differential to spontaneously arising BPNSTs and MPNSTs, as well as PNSTs arising in the setting of a neurocutaneous syndrome such as neurofibromatosis types I (NF1) and II (NF2) or schwannomatosis [12]. Apart from size and invasiveness of the lesion, there are no reliable anatomic MRI features that help distinguish BPNSTs from MPNSTs and thus, MRI features do not preclude the necessity of biopsy for definitive diagnosis of MPNSTs [13].…”

Pediatric Cancer Predisposition Imaging: Focus on Whole-Body MRI

“…Increasingly, many centers also routinely obtain images in the axial plane, although the added benefit or even optimal imaging plane is not yet fully established (20). Extending scan times can introduce motion artifact and have an impact on patient throughput, which likely further contributes to variability in sequence and imaging plane choices between different centers.…”