Ye Ju1, Ai-lian Liu1, Qing-wei Song1, Mei-yu Sun1, Jing-hong LIU1, Li-hua Chen1, Zheng Han1, Yi-min WANG1, and Li-zhi Xie2
1The First Affiliated Hospital of Dalian Medical University, Dalian, China, People's Republic of, 2GE Healthcare, MR Research China, Beijing, Beijing, China, People's Republic of
Synopsis
The
diffusion property of tumor tissues largely depends on cell density, which may
also be predictive features of malignancy in some types of tumors. Intravoxel
incoherent motion (IVIM) imaging is an extension of diffusion weighted imaging
(DWI) that can be used to investigate both diffusion and perfusion changes in
tissues. Comparing the IVIM parameters between carcinoma (HCC),
hepatic hemangioma and hepatic metastasis, we found that IVIM can facilitates
understanding of tumor tissue characteristics of perfusion and diffusion, and
it may provide more useful information to distinguish hemangiomas from other
two malignant tumors.Target audience
Physicians and scientists who are interested in
the diagnosis of hepatocellular carcinoma (HCC), hepatic hemangioma and hepatic
metastasis, as while as the application of IVIM in abdomen.
Purpose
Perfusion is an important phenomenon of many
physiological or pathological processes
[1]. Intravoxel incoherent
motion (IVIM) imaging is an extension of diffusion weighted imaging (DWI) that
can be used to investigate both diffusion and perfusion changes in tissues. It
is reported that IVIM imaging may be useful for differentiating soft tissue
tumors
[2]. Our study was to assess the IVIM parameters for
differential diagnosing hepatocellular carcinoma (HCC), hepatic hemangioma and
hepatic metastasis.
Methods
Seventy-one consecutive patients (40 men: 31
women, mean age, 62 years) with 33 hepatocellular carcinomas (HCCs), 24 hepatic
hemangiomas and 14 hepatic metastasis were enrolled in this study and inspected
conventional MR and IVIM-MR examination with 1.5-T MR imager from January 2015
to October 2015. MRI
was performed using a 1.5-T MR imager (GE-Signa HDXT) in a protocol containing
the routine T1WI, T2WI and 19 b values (0, 10, 30, 50, 80, 100, 120, 150, 180,
200, 300, 500, 800, 1000, 1200, 1500, 2000, 2500 and 3000 s/mm
2)
were used to evaluate diffusion and perfusion characteristics of IVIM. IVIM
parameters (ADCstandard, ADCslow, ADCfast, and
f) of hepatocellular carcinoma (HCC), hepatic hemangioma and hepatic metastasis
were measured by using the FuncTool on GE AW4.6 workstation (Figure 1). The MR
images were blindly reviewed and analyzed by two observers who have 3 and 10
years’ experience of MR diagnosis respectively. The SPSS17.0 statistical
software has been used for the data analysis, P value less than 0.05 was
considered statistically significant. Intraclass correlation coefficient (ICC)
test was applied to test the consistency of two observers; compared ADCstandard,
ADCslow, ADCfast and f of the three groups by Mann-Whitney
test, respectively.
Results and
Discussion
The ICC values of the IVIM parameters (ADCstandard,
ADCslow, ADCfast, and f) were all greater than 0.75 in
the three groups, exhibiting an amenable consistency (Table 1). The ADCstandard,
ADCslow and f of the hepatic hemangioma were significantly higher (p
< 0.05) than the hepatic metastasis (Table 2). The ADCstandard,
ADCslow and f of hepatic hemangioma were significantly higher (p
< 0.05) than HCC, while the ADCfast of hepatic hemangioma were
significantly lower (p < 0.05) than HCC (Table 3).The ADCstandard,
ADCslow, ADCfast and f did not show any statistically
significant difference between the HCC and the hepatic metastasis (p >
0.05). IVIM MR imaging shows a unique profile of microcirculation and pure
molecular diffusion within tumors. Our study showed that the ADCstandard values of hepatic
hemangioma were significantly higher than hepatic metastasis (p < 0.05) and
HCC (p < 0.05), since the limitation of water molecular diffusion of
malignant tumors leads to a decrease of ADC value. The ADCslow value was another effective
parameter to distinguish hemangiomas from the other two tumors. The ADCslow
with a high b value is the true diffusion coefficient of pure water in tumors
with perfusion components removed at the same time. For HCC and hepatic metastasis, the cell
membrane permeability reduced, and the water molecular diffusion limited, so the
ADCslow decreased significantly. The ADCfast of HCC was
higher than hepatic hemangioma due to the affluent microvessel perfusion of HCC. The f value
may correlate with the amount of normal angiogenesis with intact vessels in
terms of basement membrane thickness and pericyte coverage, and it increases
with the augmented tissue perfusion components. Our study showed that the f of
hepatic hemangioma were significantly higher than hepatic metastasis (p <
0.05) and HCC (p < 0.05), because the hepatic hemangioma are rich in
capillaries per unit tumor volume.
Conclusion
According to our study, the HCC, hepatic
metastasis and hepatic hemangioma showed different IVIM parameters (ADCstandard,
ADCslow, ADCfast and f values). IVIM imaging facilitates
understanding of tumor tissue characteristics of perfusion and diffusion, and
it may provide more useful information to distinguish hemangiomas from other two
malignant tumors.
Acknowledgements
No acknowledgement found.References
[1]Le Bihan D. Intravoxel Incoherent Motion
Perfusion MR Imaging: A Wake-Up Call 1[J]. Radiology, 2008, 249(3): 748-752.
[2]Du J, Li K, Zhang W, et al. Intravoxel
Incoherent Motion MR Imaging: Comparison of Diffusion and Perfusion
Characteristics for Differential Diagnosis of Soft Tissue Tumors[J]. Medicine,
2015, 94(25).