Jayant Narang MBBS, MD, Abstract Co-Author: Nothing to Disclose

Rajan Jain MD, Presenter: Research support, General Electric Company

Abbas Babajani-Feremi PhD, Abstract Co-Author: Nothing to Disclose

Syed Arbab Ali MD, PhD, Abstract Co-Author: Nothing to Disclose

Lonni Schultz, Abstract Co-Author: Nothing to Disclose

Increasing use of various combinations of aggressive chemo and radiation therapy for gliomas has led to complex post-treatment morphologic imaging appearance and ‘pseudo-progression’ is not uncommon in a busy neuro-oncologic practice. The purpose of this retrospective study was to evaluate the role of non-model based semi-quantitative indices obtained from DCET1 MR Perfusion (DCET1MRP) in diagnosing pseudo-progression. 

162 patients previously treated for a glioma at our hospital were reviewed. 48 patients (30%) showed a recurrent or progressive enhancing lesion (RPEL) within 3 months of radiotherapy. 26 patients who had DCET1MRP studies were included in the final analysis. Maximum slope of initial vascular phase (MSIVP) was calculated for each of these patients from DCET1MRP. These patients were classified into pseudo-progression group (stable or improving RPEL on follow up imaging without any change in treatment) and true-progression group (worsening RPEL with no change in treatment or stable RPEL with additional anti-angiogenic treatment). . A two sample t-test was done to assess the difference between the two groups. The t-test was done on the log transformations of the MSIVP because of the large differences in variability among the two groups.  

4 (15.3%) out of 26 were diagnosed with pseudo-progression and 22 (84.7%) as true-progression. There was statistically significant difference between these two groups with pseudo-progression group having a mean MSIVP of 39.97±14.91 and true-progression group with mean MSIVP of 82.18 ± 37.64 (p= 0.011). 8 patients out of 22 true-progression cases received anti-angiogenic therapy and showed favorable imaging response despite having high MSIVP (68.36±25.94)

Our results show that semi-quantitative indices derived from DCET1MRP may differentiate pseudo-progression from true-progression. Also changing treatment based on MSIVP values at the time of diagnosis of RPEL may improve patient prognosis as evidenced by imaging response noted in 8 of the true-progression cases which is contradictory to current RANO recommendations.

This study highlights the use of DCET1MRP in reliably predicting the diagnosis of pseudo-progression in previously treated gliomas, a very important concern in a busy neuro-oncologic practice.  

Narang, J, Jain, R, Babajani-Feremi, A, Ali, S, Schultz, L, Role of Nonmodel-based Semi-quantitative Indices Obtained from DCET1 MR Perfusion in Differentiating Pseudo-progression from True Progression in Brain Tumors.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11009205.html