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TH‐E‐ValB‐05: Analysis of Early Treatment Failure in Patients with Newly Diagnosed GBM Using Advanced MR Imaging
Author(s) -
Choy R,
Ozturk E,
Crawford F W,
Chang S M,
Nelson S J,
Pirzkall A
Publication year - 2006
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.2241946
Subject(s) - nuclear medicine , medicine , diffusion imaging , creatine , effective diffusion coefficient , hyperintensity , magnetic resonance imaging , statistical significance , white matter , perfusion , radiology
Purpose: To seek imaging characteristics predictive of early treatment failure (EF) following concurrent radiation/chemotherapy (RT/CHT) in patients with newly diagnosed GBM s/p surgical resection using advanced MRI techniques (3D 1 H spectroscopy (MRSI), diffusion weighted (DWI) and perfusion weighted (PWI) imaging). Methods and Materials: 26 patients were imaged at 1.5T prior to RT/CHT (pre‐RT) and immediately after RT (post‐RT). Analyzed imaging parameters included peak heights of choline (Cho), creatine, N‐acetyl‐aspartate (NAA), lactate and lipid; Cho‐to‐NAA (CNI), Cho‐to‐Cr (CCrI) indices and excess‐choline (Ex(Cho)); parametric maps of percent‐recovery and apparent diffusion coefficient (ADC) were calculated. Mutually exclusive morphologic abnormalities were contoured as contrast‐enhancement (CE), T2‐hyperintensity (T2), resection‐cavity, necrosis, and a reference for normal appearing white matter. Patients were categorized as EF if any new CE appeared or if the CE volume increased by >25% at post‐RT. Imaging parameters were subjected to a Wilcoxon Rank Sum to test statistical significance between EF and non‐EF. Results: 9/26 patients were classified as EF. Both patient groups did not differ statistically in terms of age, volume of CE or T2 at pre‐RT. There were trends to higher Cho, CNI, and Ex(Cho) for the EF group at pre‐RT, however, these did not reach statistical significance. Statistically significant findings within CE at post‐RT were mainly associated with Cho and related indices and included lower ADC and %recovery values suggesting higher cellularity and increased leakiness of vessels in the EF vs non‐EF group. Conclusion: Even though our preliminary data on 26 patients could not identify imaging parameters significantly different between EF and non‐EF patients at pre‐RT, the demonstrated trend encourages further evaluation of additional 31 additional patient data sets acquired at 3T in order to increase statistical power. In addition, the reported significant changes at post‐RT suggest that the parameters may be valuable in assessing treatment effects.