RPS 616 - Imaging for response assessment and prognostication

Author Block: S. J. Choi, K. W. Kim, D. W. Kim, h. ahn; Seoul/KR
Purpose or Learning Objective: Diffusion-weighted imaging that reflects tumour cellularity is emerging as a preferred method for evaluating the response in oncologic imaging. For the clinical utilization of DWI as a quantitative parameter, the repeatability and accuracy of the ADC value is critical. In this study, we aimed to validate variable MRI systems using Quantitative Imaging Biomarkers Alliance (QIBA)/ National Institute of Standards and Technology (NIST) protocols and to confirm the reliability of currently used clinical DWI protocols.
Methods or Background: In this prospective study, a NIST/QIBA developed phantom with 13 PVP vials of known ADC value was used. The validation of the MRI systems was performed on four 1.5T and 3.0T MRI systems using the QIBA and the clinically used DWI protocols. Acquired DWI images were analyzed by commercially available web-based software (CaliberMRI, Inc., qCal-MR QC Software), and the parameters for quality control according to the QIBA claim were assessed. The linearity and bias of ADC measurement for each DWI protocol were calculated with linear regression. The difference of ADC values between the two protocols was evaluated with a paired T-test and a Bland-Altman plot.
Results or Findings: The regression slope of estimated ADC values on all MRI systems were 1.01 (range, 1.001.02) for the QIBA protocol and 1.02 (0.951.02) for the clinical protocol within the QIBA claim. The estimated ADC values were not statistically different between the two DWI protocols.
Conclusion: ADC estimation from variable MRI systems using QIBA and clinical protocols was accurate, and ADC could be considered as imaging biomarker in the clinical field.
Limitations: This study was performed with a small number of MRI examinations using four MRI systems. Further studies with more examinations and MRI systems are needed to robust DWI's usefulness.
Ethics committee approval: This prospective study included no human participants and was exempt from the institutional board review.
Funding for this study: Nothing to disclosure here.

Author Block: S. Rizzo¹, M. Del Grande¹, G. M. M. Nicolino², I. Colombo¹, L. Rossi¹, M. Biroli², L. Manganaro³, F. Del Grande¹; ¹Lugano/CH, ²Milan/IT, ³Rome/IT
Purpose or Learning Objective: To assess the association between computed tomography (CT) quantitative measures of body composition profiling and chemotherapy-related complications in patients with ovarian cancer. Secondary purposes were to evaluate association between sarcopenia and survival, and differences in body composition profiling at baseline and after neoadjuvant chemotherapy.
Methods or Background: The study population was retrospectively selected from patients with newly diagnosed ovarian cancer. Clinical data were recorded, and CT images at the level of the 3rd lumbar vertebra were stored. By using specific software, skeletal muscle area (SMA), subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT), and skeletal muscle density (SMD) were extracted. The skeletal muscle index (SMI) was calculated. Statistical analysis was performed to identify body composition features predictive of dose reduction, premature end of chemotherapy and cycle delays. Kaplan-Meier analyses were performed to assess overall survival (OS) and progression-free survival (PFS). Wilcoxon test was performed to compare body composition features before and after neoadjuvant chemotherapy (NACT).
Results or Findings: Sixty-nine patients were included. A significant association was found between VAT and cycle delays (OR=1.01, z=2.01, 95%CI: 1.00-1.02, p< 0.05), between SMA and early discontinuation of chemotherapy (OR=1.03, z=2.10, 95% CI: 1.00-1.05, p< 0.05), and between mean SMD and cycle delays (OR=0.92, z=-2.70, 95%CI: 0.87-0.98, p< 0.01). No significant difference emerged for OS in sarcopenic and non-sarcopenic patients, nor in CT body composition features before and after NACT.
Conclusion: In ovarian cancer patients, CT-derived body composition profiling might predict the risk of chemotoxicity. In particular, VAT and SMD are associated with chemotherapy cycle delays and SMA with early discontinuation of chemotherapy.
Limitations: No limitations identified.
Ethics committee approval: The ethics committee approval was obtained.
Funding for this study: No funding was received for this study.