Apparent transverse relaxation (R2∗) on MRI as a method to differentiate treatment effect (pseudoprogression) versus progressive disease in chemoradiation for malignant glioma

Academic Article

Abstract

  • Introduction: Pseudoprogression (psPD) is a transient post-treatment imaging change that is commonly seen when treating glioma with chemotherapy and radiation. The use of apparent transverse relaxation rate (R2*), which is calculated from a contrast-free multi-echo gradient echo Magnetic Resonance Imaging (MRI) sequence, may allow for quantitative identification of patients with suspected psPD. Methods: We acquired a multi-echo gradient echo sequence using a 3T-Siemens Prisma MRI. The signal decay through the echoes was fitted to provide the (R2*) coefficient. We segmented the T1-gadolinium enhancing the image to provide a contrast enhancing lesion (CEL) and the FLAIR hyperintensity to provide a non-enhancing lesion (NEL). These regions of interest were applied to the multi-echo gradient echo to acquire a mean (R2*) within the CEL and NEL. We additionally acquired ADC data to attempt to corroborate our findings. Results: We found that patients who later exhibited PD exhibited a higher (R2*) within the CEL as well as a higher ratio of CEL to NEL. Our data correctly distinguished pseudoprogression from treatment effect in 9/9 patients, while ADC corrected identified 7/9 patients using an absolute ADC of 1200 × 10−6mm2/s. Conclusions: Our method seems promising for the accurate identification of psPD, and the technique is amenable to evaluation in larger, multi-centre patient cohorts.
  • Digital Object Identifier (doi)

    Author List

  • Belliveau JG; Bauman GS; Macdonald D; Macdonald M; Klassen LM; Menon RS
  • Start Page

  • 224
  • End Page

  • 231
  • Volume

  • 62
  • Issue

  • 2