Intravoxel incoherent motion-derived histogram metrics for assessment of response after combined chemotherapy and radiation therapy in rectal cancer: Initial experience and comparison between single-section and volumetric analyses1 Journal Article


Authors: Nougaret, S.; Vargas, H. A.; Lakhman, Y.; Sudre, R.; Do, R. K. G.; Bibeau, F.; Azria, D.; Assenat, E.; Molinari, N.; Pierredon, M. A.; Rouanet, P.; Guiu, B.
Article Title: Intravoxel incoherent motion-derived histogram metrics for assessment of response after combined chemotherapy and radiation therapy in rectal cancer: Initial experience and comparison between single-section and volumetric analyses1
Abstract: Purpose: To determine the diagnostic performance of intravoxel incoherent motion (IVIM) parameters and apparent diffusion coefficient (ADC) to assess response to combined chemotherapy and radiation therapy (CRT) in patients with rectal cancer by using histogram analysis derived from whole-tumor volumes and single-section regions of interest (ROIs). Materials and Methods: The institutional review board approved this retrospective study of 31 patients with rectal cancer who underwent magnetic resonance (MR) imaging before and after CRT, including diffusion-weighted imaging with 34 b values prior to surgery. Patient consent was not required. ADC, perfusion-related diffusion fraction (f), slow diffusion coefficient (D), and fast diffusion coefficient (D∗) were calculated on MR images acquired before and after CRT by using biexponential fitting. ADC and IVIM histogram metrics and median values were obtained by using whole-tumor volume and single-section ROI analyses. All ADC and IVIM parameters obtained before and after CRT were compared with histopathologic findings by using t tests with Holm-Sidak correction. Receiver operating characteristic curves were generated to evaluate the diagnostic performance of IVIM parameters derived from whole-tumor volume and single-section ROIs for prediction of histopathologic response. Results: Extreme values aside, results of histogram analysis of ADC and IVIM were equivalent to median values for tumor response assessment (P >.06). Prior to CRT, none of the median ADC and IVIM diffusion metrics correlated with subsequent tumor response (P >.36). Median D and ADC values derived from either whole-volume or single-section analysis increased significantly after CRT (P ≤.01) and were significantly higher in good versus poor responders (P ≤.02). Median IVIM f and D∗values did not significantly change after CRT and were not associated with tumor response to CRT (P >.36). Interobserver agreement was excellent for whole-tumor volume analysis (range, 0.91-0.95) but was only moderate for singlesection ROI analysis (range, 0.50-0.63). Conclusion: Median D and ADC values obtained after CRT were useful for discrimination between good and poor responders. Histogram metrics did not add to the median values for assessment of tumor response. Volumetric analysis demonstrated better interobserver reproducibility when compared with single-section ROI analysis. © 2016 RSNA.
Journal Title: Radiology
Volume: 280
Issue: 2
ISSN: 0033-8419
Publisher: Radiological Society of North America, Inc.  
Date Published: 2016-08-01
Start Page: 446
End Page: 454
Language: English
DOI: 10.1148/radiol.2016150702
PROVIDER: scopus
PMCID: PMC4976464
PUBMED: 26919562
DOI/URL:
Notes: Article -- Export Date: 1 September 2016 -- Source: Scopus
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MSK Authors
  1. Yuliya Lakhman
    34 Lakhman
  2. Kinh Gian Do
    116 Do