Pseudoprogression of brain tumors

• Published in: Journal of magnetic resonance imaging Vol. 48; no. 3; pp. 571 - 589
• Main Authors: Thust, Stefanie C., van den Bent, Martin J., Smits, Marion
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01.09.2018; John Wiley and Sons Inc
• Subjects: Accuracy; Brain; Brain cancer; brain neoplasms; Brain tumors; Clinical trials; CME; Contrast agents; Data processing; Diagnostic systems; diffusion; Glioma; Magnetic resonance imaging; Magnetic resonance spectroscopy; Medical imaging; Medical research; MRI; Neuroimaging; NMR; Nuclear magnetic resonance; Perfusion; perfusion weighted; proton magnetic resonance spectroscopy; Technology assessment; Tumors; diffusion; magnetic resonance imaging; MRI; glioma; perfusion weighted; brain neoplasms; proton magnetic resonance spectroscopy
• ISSN: 1053-1807; 1522-2586; 1522-2586
• DOI: 10.1002/jmri.26171

This review describes the definition, incidence, clinical implications, and magnetic resonance imaging (MRI) findings of pseudoprogression of brain tumors, in particular, but not limited to, high‐grade glioma. Pseudoprogression is an important clinical problem after brain tumor treatment, interfering not only with day‐to‐day patient care but also the execution and interpretation of clinical trials. Radiologically, pseudoprogression is defined as a new or enlarging area(s) of contrast agent enhancement, in the absence of true tumor growth, which subsides or stabilizes without a change in therapy. The clinical definitions of pseudoprogression have been quite variable, which may explain some of the differences in reported incidences, which range from 9–30%. Conventional structural MRI is insufficient for distinguishing pseudoprogression from true progressive disease, and advanced imaging is needed to obtain higher levels of diagnostic certainty. Perfusion MRI is the most widely used imaging technique to diagnose pseudoprogression and has high reported diagnostic accuracy. Diagnostic performance of MR spectroscopy (MRS) appears to be somewhat higher, but MRS is less suitable for the routine and universal application in brain tumor follow‐up. The combination of MRS and diffusion‐weighted imaging and/or perfusion MRI seems to be particularly powerful, with diagnostic accuracy reaching up to or even greater than 90%. While diagnostic performance can be high with appropriate implementation and interpretation, even a combination of techniques, however, does not provide 100% accuracy. It should also be noted that most studies to date are small, heterogeneous, and retrospective in nature. Future improvements in diagnostic accuracy can be expected with harmonization of acquisition and postprocessing, quantitative MRI and computer‐aided diagnostic technology, and meticulous evaluation with clinical and pathological data. Level of Evidence: 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;48:571–589.