Content area
Full Text
Eur Radiol (2013) 23:428434 DOI 10.1007/s00330-012-2604-1
MAGNETIC RESONANCE
Measurement reproducibility of perfusion fractionand pseudodiffusion coefficient derived by intravoxel incoherent motion diffusion-weighted MR imaging in normal liver and metastases
A. Andreou & D. M. Koh & D. J. Collins & M. Blackledge &
T. Wallace & M. O. Leach & M. R. Orton
Received: 28 March 2012 /Accepted: 1 July 2012 /Published online: 6 October 2012 # European Society of Radiology 2012
AbstractObjective To determine the measurement reproducibility of perfusion fraction f, pseudodiffusion coefficient D* and diffusion coefficient D in colorectal liver metastases and normal liver.
Methods Fourteen patients with known colorectal liver metastases were examined twice using respiratory-triggered echo-planar DW-MRI with eight b values (0 to 900 s/ mm2) 1 h apart. Regions of interests were drawn around target metastasis and normal liver in each patient to derive ADC (all b values), ADChigh (b values 100 s/mm2) and intravoxel incoherent motion (IVIM) parameters f, D* and D by least squares data fitting. Short-term measurement reproducibility of median ADC, ADChigh, f, D* and D values
were derived from BlandAltman analysis.
Results The measurement reproducibility for ADC, ADChigh and D was worst in colorectal liver metastases
(21 % to +25 %) compared with liver parenchyma (6 % to +8 %). Poor measurement reproducibility was observed for the perfusion-sensitive parameters of f (75 % to +241 %)
and D* (89 % to +2,120 %) in metastases, and to a lesser extent the f (24 % to +25 %) and D* (31 % to +59 %) of liver.
Conclusions Estimates of f and D* derived from the widely used least squares IVIM fitting showed poor measurement
reproducibility. Efforts should be made to improve the measurement reproducibility of perfusion-sensitive IVIM parameters.
Key Points Quantitative diffusion-weighted MRI parameters are increasingly used for clinical management decisions.
However perfusion-sensitive intravoxel incoherent motion (IVIM) parameters showed poor measurement reproducibility.
Measurement reproducibility of IVIM parameters was worse in metastases than normal liver.
Efforts to improve measurement reproducibility of IVIM parameters should be explored.
Keywords IVIM . Diffusion . Perfusion . Liver . Metastases
Introduction
Quantitative parameters derived from diffusion-weighted MR imaging (DW-MRI) are being utilised for lesion char-acterisation and for assessing treatment response. However, the calculation of apparent diffusion coefficient (ADC) by assuming a monoexponential...