Bo Ma, Abstract Co-Author: Nothing to Disclose

Xiaohua Hong, Abstract Co-Author: Nothing to Disclose

Meiyun Wang MD, PhD, Abstract Co-Author: Nothing to Disclose

Hong Zhang MD, Abstract Co-Author: Nothing to Disclose

Jaishri Blakely MD, Abstract Co-Author: Nothing to Disclose

Jinyuan Zhou PhD, Presenter: Nothing to Disclose

Amide proton transfer (APT) imaging is a novel molecular imaging approach that generates MRI contrast based on endogenous cellular proteins in tissue. The purpose of this study was to determine whether APT imaging can distinguish pseudoprogression from true progression or recurrence in patients with malignant glioma.

Total 53 patients with pathologically confirmed high-grade gliomas (anaplastic astrocytoma or glioblastoma) were assessed. All patients provided written informed consent as required. Eligibility criteria included: treated with concurrent chemotherapy and radiation therapy (CCRT) after surgical resection, developed new or enlarged contrast enhanced lesions after CCRT, and had standard clinical MRI before and after CCRT. APT-MRI scanning was performed at 3T (3D sequence; 15 slices; 4.4 mm thickness). APT-weighted MRI signals were calculated using magnetization transfer ratio asymmetry at 3.5ppm with respect to water. MRI analysis was made, blinded to pathologic diagnosis, based on longitudinal signal changes in T2W, FLAIR, DWI and gadolinium enhancement on T1W, lasting at least six months.

Longitudinal radiological analysis showed that 39 patients had true progression or recurrence and 14 patients had pseudoprogression. The true progression or recurrence is associated with APT hyperintensity, compared to contralateral normal-appear white matter, while pseudoprogression is associated with APT isointensity to mild hyperintensity. The average APT signal intensity was significantly higher in the true progression/recurrence group (2.76%  0.55%) than in the pseudoprogression group (1.19%  0.40%; P < 0.001). Based on the receiver operating characteristic (ROC) analysis, the cutoff APT signal intensity value was 1.89%, with a sensitivity of 100% and a specificity of 92.9%.

The APT-MRI signal may be a valuable imaging biomarker to distinguish between tumor progression or recurrence and pseudoprogression whose diagnosis typically needs repeated surgery or longitudinal MRI scanning over several months.

APT image can help distinguish pseudoprogression from true progression or recurrence. Such a distinction may avoid the time-consuming longitudinal MRI analysis and repeated craniotomy or biopsy.

Ma, B, Hong, X, Wang, M, Zhang, H, Blakely, J, Zhou, J, Distinguishing Pseudoprogression from True Progression or Recurrence of Malignant Glioma Using Amide Proton Transfer MR Imaging.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14006213.html