Giovanni Morana MD, Presenter: Nothing to Disclose

Giuliano Scattolin MD, Abstract Co-Author: Nothing to Disclose

Riccardo Zanato, Abstract Co-Author: Nothing to Disclose

Federica De Leo, Abstract Co-Author: Nothing to Disclose

Alex Faccinetto, Abstract Co-Author: Nothing to Disclose

Michele Fusaro, Abstract Co-Author: Nothing to Disclose

Dow-Mu Koh MD, FRCR, Abstract Co-Author: Nothing to Disclose

We investigate diffusion coefficients, evaluated with intravoxel incoherent motion (IVIM) model, in both hypervascular and hypovascular liver lesions (HCC, FNH and colorectal metastases), in their different parameters: apparent diffusion coefficient (ADC); perfusion fraction (f); diffusion and pseudodiffusion coefficient (D and D*). We evaluated how IVIM parameters change according to the number of b values utilized in their analysis.  

Retrospective study of 96 patients with differents diagnosis: HCC (n=28; path proof) FNH (n=44; Liver specific CM uptake and follow-up) CCM (colorectal carcinoma metastasis: n=24; path proof). MR: Siemens Avanto, 1.5 T with quantum gradients. DWI sequence: EPI (WIP511c; TR/TE=4361/54ms) with 11 b-values (0, 10, 20, 30, 50, 70, 100, 150, 200, 400, 800 sec / mm2). Using MatLab, the estimations of D, D* and f were carried out for different combination of b-values: C1 (11 values: 0, 10,20, 30, 50, 70, 100, 150, 200, 400, 800 sec/ mm2), C2 (9 values: 0, 20, 30, 50, 70, 100, 200, 400, 800 sec/ mm2); C3 (7 values: 0,50, 100, 150, 200, 400, 800 sec/ mm2). Statistics Analysis: box plots and scatter plot;2 sample t test; Kruskal-Wallis and Wilcoxon test.  

With 11 b values: - ADC and D were not significantly different between lesions. - HCC vs FNH: D* and f were not significantly different between HCC and FNH; both were significantly higher than in CCM. - Perfusion fraction (f%) was significantly higher in HCC and FNH versus CCM. With lesser b values (C2,C3): - D* shows a significant (p< 0.05) decrease in HCC, not significantly decrease in FNH and in CCM. Not statistically difference between lesions - ADC shows a significant (p< 0.05) decrease for ALL lesion (C1 vs C3). Not statistically difference between lesions - D does not change - f% does not show a significantly decrease in the above groups, thus maintaining the statistical difference (HCC/FNH >> CCM).    

DWI and IVIM parameters are dependent on number of b values, with the exception of f% and D. Higher b values are more helpful for dd. Quantitative analysis is highly dependent on the sequence. There is a need for standardization of sequences.

Perfusion fraction is independent from the number of b values and is a useful indicator for differential diagnosis.

Morana, G, Scattolin, G, Zanato, R, De Leo, F, Faccinetto, A, Fusaro, M, Koh, D, DWI of Liver Lesions: IVIM Model with Different Combination of 11 b Values.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14018727.html