Intracranial meningioma surveillance using volumetrics from T2‐weighted MRI

Abstract

Background and Purpose:The gold standard for imaging of meningiomas is MRI with gadolinium-based contrast agent. Due to increased costs, time, and uncertain chronic effects of gadolinium exposure, use of noncontrast T2-weighted imaging (T2WI) in lieu of contrast-enhanced MRI has been an increasing focus of research across various diagnostic scenarios. The purpose of this study was to evaluate the diagnostic accuracy of T2WI in detecting changes in meningioma tumor volume. Methods: Imaging and clinical data were reviewed for 82 consecutive patients undergoing MR-surveillance of intracranial meningioma. Using volumetric-T2WI, two neuroradiologists independently calculated tumor volumes. Measurements were compared to a baseline study contrast-enhanced T1 tumor volume. Using contrast-enhanced sequences as the reference standard, statistical analysis was performed to determine the accuracy of T2WI in detecting changes of meningioma volume. Results: Using only T2WI, readers detected meningioma volume change ≥ 20% in 19/82 patients and volume change <20% in 63/82 patients. Reader accuracy for detecting change in tumor volume on T2WI ≥ 20% was 0.85, sensitivity 0.65, specificity 0.93, positive predictive value (PPV) 0.79, and negative predictive value (NPV) 0.87. For meningiomas >1 ml, reader accuracy for detecting change in tumor volume on T2WI ≥20% was 0.90, sensitivity 0.78, specificity 0.95, PPV 0.88, and NPV 0.91. Change in tumor volume on T2WI ≥20% was detected with 100% accuracy for posterior fossa meningiomas. Interreader agreement for all meningiomas was moderate (κ = 0.45) improving to substantial agreement (κ = 0.77) with tumor volumes >1 ml. Conclusion: Volumetric-T2WI detects changes in meningioma volume with comparable accuracy to gold standard T1 postcontrast imaging, particularly with higher tumor volumes and posterior fossa locations.

Reducing Gadolinium Exposure in Patients Undergoing Monitoring for Meningiomas

“…Similarly, T2-weighted imaging was able to accurately measure the size and detect changes in meningioma volume with similar efficacy as T1 post-contrast images, especially tumors >1 mL and those located in the posterior fossa [19,21]. Finally, a recent study by Boto and colleagues found excellent agreement, as measured by intraclass correlation coefficients, between various measurements of meningioma size and growth between T1 three-dimensional gadolinium and two-dimensional T2-weighted imaging [22].…”

“…These findings indicate that the measurements of meningioma diameter obtained from T1 post-contrast, T2 FSE, and T2 FLAIR by these observers are precise and that comparisons of each observer's measurements between imaging techniques are reflective of the accuracy of the instrument used to measure them. Additionally, a similar study found that two neuroradiologists with 20 years difference in imaging reading were able to maintain moderate agreement between meningioma volume (κ = 0.45), which improved to substantial for meningiomas >1 mL (κ = 0.77), suggesting that even less experienced observers can still make accurate measurements [19]. Because these prerequisite findings demonstrated adequate reliability of our observers and the instruments of measure, subsequent analysis of the agreement between meningioma diameter measurements between imaging techniques was appropriate.…”

“…The fact that the majority of meningiomas can be measured with non-contrast imaging, along with the similar agreement between T1 and T2 measurements of meningioma tumor size and growth in the present study and prior studies could have significant implications for meningioma surveillance. Namely, they provide substantial evidence that a conversion from gold-standard contrast imaging to non-contrast imaging could avoid contrast-related toxicities without sacrificing efficacy in select patients [19][20][21][22].…”

“…Despite these findings, gadolinium-based MRI should remain a critical tool in the management of certain meningioma patients given the superior efficacy of contrast in visualizing various aspects of meningioma growth relative to T2 imaging, including those of smaller volume (i.e., <1 mL), en plaque meningiomas, and those with enhancing dural tails [19,24,25]. Indeed, current European Association of Neuro-Oncology (EANO) guidelines recommend a wait-and-see approach for patients with normal life expectancy who have small (i.e., <3 cm) and/or asymptomatic tumors where contrast imaging is used six months after diagnosis, annually for five years, and then biannually [2].…”