Erschienen in:
01.10.2013 | Magnetic Resonance
Intravoxel incoherent motion model-based liver lesion characterisation from three b-value diffusion-weighted MRI
verfasst von:
A.-H. Penner, A. M. Sprinkart, G. M. Kukuk, I. Gütgemann, J. Gieseke, H. H. Schild, W. A. Willinek, P. Mürtz
Erschienen in:
European Radiology
|
Ausgabe 10/2013
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Abstract
Objective
To evaluate intravoxel incoherent motion (IVIM) model-based liver lesion characterisation from three b-value diffusion-weighted imaging (DWI).
Methods
The 1.5-T DWI data from a respiratory gated spin-echo echo-planar magnetic resonance imaging sequence (b = 0, 50, 800 s/mm2) were retrospectively analysed in 38 patients with different liver lesions. Conventional apparent diffusion coefficient ADC = ADC(0,800) as well as IVIM-based parameters D′ = ADC(50,800), ADC_low = ADC(0,50), and f′ were calculated voxel-wise. Sixty-one regions of interest in hepatocellular carcinomas (HCCs, n = 24), haemangiomas (HEMs, n = 11), focal nodular hyperplasias (FNHs, n = 11), and healthy liver tissue (REFs, n = 15) were analysed. Group differences were investigated using Student’s t-test and receiver-operating characteristic (ROC) analysis.
Results
Mean values ± standard deviations of ADC, D′, ADC_low (in 10-5 mm2/s), and f′ (in %) for REFs/FNHs/HEMs/HCCs were 130 ± 11/143 ± 27/168 ± 16/113 ± 25, 104 ± 12/123 ± 25/162 ± 18/102 ± 23, 518 ± 66/437 ± 97/268 ± 69/283 ± 120, and 18 ± 3/14 ± 4/6 ± 3/9 ± 5, respectively. Differences between lesions and REFs were more significant for IVIM-based parameters than for conventional ADC. ROC analysis showed the best discriminability between HCCs and FNHs for ADC_low and f′ and between HEMs and FNHs or HCCs for D′.
Conclusion
Three instead of two b-value DWI enables a numerically stable and voxel-wise IVIM-based analysis for improved liver lesion characterisation with tolerable acquisition time.
Key Points
• Quantitative analysis of diffusion-weighted MRI helps liver lesion characterisation.
• Analysis of intravoxel incoherent motion is superior to apparent diffusion coefficient determination.
• Only three b-values enable separation of diffusion and microcirculation effects.
• The method presented is numerically stable, with voxel-wise results and short acquisition times.