01.02.2013 | Magnetic Resonance | Ausgabe 2/2013
Measurement reproducibility of perfusion fraction and 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
To determine the measurement reproducibility of perfusion fraction f, pseudodiffusion coefficient D
* and diffusion coefficient D in colorectal liver metastases and normal liver.
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 Bland–Altman analysis.
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.
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.
• 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.