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Intravoxel Incoherent Motion Diffusion-weighted imaging for evaluating the pancreatic perfusion in cirrhotic patients
Ran Hu1, Hua Yang1, and Lisha Nie2
1Radiology, Chongqing Hospital of Traditional Chinese Medicine, Chongqing, China, 2MR Research China, GE Healthcare, Beijing, China

Synopsis

Keywords: IVIM, Liver, liver cirrhosis, perfusion

Motivation: Pancreatic perfusion disturbances is found in cirrhotic patients with portal hypertension, which is correlated with reduced insulin secretion. Intravoxel incoherent motion (IVIM) can noninvasively reflect tissue microcapillary perfusion.

Goal(s): To assess the characteristics of pancreatic perfusion in normal pancreas vs. cirrhotic patients using IVIM.

Approach: 67 cirrhotic patients and 33 healthy subjects underwent IVIM on a 3.0 T MRI scanner.

Results: The f value of pancreas in cirrhotic was lower than that in normal group (p = 0.01). In cirrhotic group, the f value of pancreas decreased with the increase of the Child-Pugh classification (R = -0.49, p = 0.00).

Impact: IVIM-derived perfusion-related parameter (f value) could be helpful to evaluate pancreatic perfusion in liver cirrhosis. Pancreatic perfusion decreased is present in liver cirrhosis, and pancreatic perfusion tends to decrease with the increasing severity of hepatic function.

Introduction

Pancreatic perfusion disturbance is found in cirrhotic patients with portal hypertension, which is correlated with reduced insulin secretion. Previous study found decreased arterial perfusion of the pancreas in cirrhotic patients compared to non-cirrhotic patients by using perfusion CT [1]. However, CT involves irradiation exposure and requires an intravenous injection of the iodinated medium. Intravoxel incoherent motion (IVIM) can noninvasively reflect tissue microcapillary perfusion. The IVIM-derived parameter (f value) has been widely used as an imaging marker for assessing microcirculation perfusion in pancreatic tumors [2, 3]. In this study, we used IVIM-DWI to assess the characteristics of pancreatic perfusion in normal pancreas versus cirrhotic patients using IVIM.

Methods

This study was approved by the institutional review board, and written informed consent was obtained from all subjects.
Patients
Sixty-seven cirrhotic patients and 33 healthy subjects underwent IVIM on a 3.0 T MRI scanner.
MRI Acquisition
All subjects underwent IVIM on a 3.0 T MRI scanner (Signa Architect, GE Healthcare, Waukesha, USA) equipped with an adaptive imaging receive coil. IVIM was performed using single-shot EPI with respiratory gating and parallel acquisition (TR/TE, 5000/75.5 ms; FOV, 36 × 36 cm2; matrix, 130×130; thickness, 3.6 mm; spacing, 0.5 mm; slices,18; b values, 0, 10, 20, 50, 100, 200, 400, 600, 800, and 1000 s/mm2; NEX, 2, 2, 2, 2, 1, 1, 1, 1, 2, and 2; scan time, 5 min 18 s) with diffusion sensitization in three directions.
Image data analysis and processing
The post-processing of IVIM images was performed on AW workstation (version 4.6, GE Healthcare) using the MADC software. As shown in Fig. 1, regions of interest (ROI) were delineated in the IVIM images with a b value of 10 s/mm2. Three ROIs were manually drawn at each anatomic location (head, body, and tail) of the pancreas. The final ROIs were then copied to IVIM-derived quantitative maps to obtain the average ADCslow, ADCfast, and f values.
The cirrhotic patients were classified into three classes according to the Child-Pugh score [3]: class A (5-6 points), class B (7-9 points), and class C (10-15 points).
Statistical analysis
All statistical analyses were performed using SPSS for Windows (version 22.0, Chicago, IL, USA). The Wilcoxon rank sum test was used to compare IVIM-derived parameters between cirrhotic and control groups. Spearman's rank correlation was used to analyze the relationship between IVIM-derived parameters and different classes of hepatic function. The Kruskal-Wallis H test was performed to compare IVIM-derived parameters among cirrhotic patients with different classes of hepatic function.

Results

The clinical characteristics of the subjects are outlined in Figure 2.
The f value of the pancreas in cirrhotic patients was significantly lower than that in normal subjects (p = 0.01) (Fig. 3a-c). In the cirrhotic group, the f value of the pancreas decreased with the increase of the Child-Pugh classification (R = -0.49, p = 0.00) (Fig. 4a-c). The f value of the pancreas was significantly higher in Child-Pugh class A patients than in class B and C patients (p = 0.02, 0.00, respectively), whereas there was no significant difference between class B and C patients (p = 0.16) (Fig. 5a-c).

Discussion and Conclusion

The f value mainly reflects the microcirculation perfusion [4]. The present study suggested that pancreatic perfusion in cirrhotic was decreased compared with that in control subjects. Kuroda et al. found that profound damage occurred to the intima of the pancreatic vessels in cirrhotic patients with portal hypertension, which could result in impaired drainage blood flow [5]. Besides, cirrhotic patients with liver dysfunction can have impaired inactivation of vasoactive substances, which can cause the imbalance of the vasomotor activity and hemodynamic disturbances [6-8].
The f value of pancreas decreased with the increasing severity of hepatic function, while the f values of class B and C patients were not significantly different. With the increasing severity of hepatic function, the portal vein pressure increases, and pancreatic congestion becomes more severe. Pancreatic congestion can lead to hypoxia and impaired microcirculation, decreasing pancreatic perfusion [8]. Pancreatic congestion in liver cirrhosis can lead to pancreatic islet dysfunction [5]. A previous study suggested significantly lower pancreatic islet function in Child-Pugh class B and C than in class A patients and no difference between class B and C [10]. This may explain the lack of difference in f values between class B and C cirrhotic patients.
Pancreatic perfusion decreased is present in liver cirrhosis, and pancreatic perfusion tends to decrease with the increasing severity of hepatic function.

Acknowledgements

The authors would like to express their deepest gratitude to the technicians who performed IVIM-MRI scans on all subjects in the department of radiology, Chongqing Hospital of Traditional Chinese Medicine, Chongqing, China.

This work was supported by the Chengdu University of Traditional Chinese Medicine "Xinglin Scholars" Discipline Talents Research Promotion Plan [grant numbers YYZX2021059].

References

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[2] Kang KM, Lee JM, Yoon JH, Kiefer B, Han JK, Choi BI (2014) Intravoxel incoherent motion diffusion-weighted MR imaging for characterization of focal pancreatic lesions. Radiology, 270:444-453. doi: https://doi .org/10.1148/radiol.13122712

[3] Klauss M, Lemke A, Grünberg K, Simon D, Re TJ, Wente MN (2011) Intravoxel incoherent motion MRI for the differentiation between mass forming chronic pancreatitis and pancreatic carcinoma. Invest Radiol 46:57-63. doi: https://doi .org/10.1097/RLI.0b013e3181fb3bf2

[4] Le Bihan D, Breton E, Lallemand D, Aubin ML, Vignaud J, Laval-Jeantet M (1988) Separation of diffusion and perfusion in intravoxel incoherent motion MR imaging. Radiology 168:497–505. doi: https://doi .org/10.1148/radiology.168.2.3393671

[5] Kuroda T, Hirooka M, Koizumi M et al (2015) Pancreatic congestion in liver cirrhosis correlates with impaired insulin secretion. J Gastroenterol 50:683–93. doi: https://doi .org/10.1007/s00535-014-1001-8

[6] Møller S, Bendtsen F (2018) The pathophysiology of arterial vasodilatation and hyperdynamic circulation in cirrhosis. Liver Int 38:570-580. doi: https://doi.org/10.1111/liv.13589

[7] McAvoy NC, Semple S, Richards JM et al (2016) Differential visceral blood flow in the hyperdynamic circulation of patients with liver cirrhosis. Aliment Pharmacol Ther 43:947-954. doi: https://doi .org/10.1111/apt.13571

[8] Steib CJ, Gerbes AL, Bystron M et al (2007) Kupffer cell activation in normal and fibrotic livers increases portal pressure via thromboxane A(2). J Hepatol 47:228-238. doi: https://doi .org/10.1016/j.jhep.2007.03.019

[9] Imamura Y, Kumagi T, Kuroda T et al (2021) Pancreas stiffness in liver cirrhosis is an indicator of insulin secretion caused by portal hypertension and pancreatic congestion. Hepatol Res 51:1-11. doi: https://doi .org/10.1111/hepr.13672

[10] Grancini V, Trombetta M, Lunati ME et al (2015) Contribution of β-cell dysfunction and insulin resistance to cirrhosis-associated diabetes: role of severity of liver disease. J Hepatol 63:1484-90. doi: https://doi .org/10.1016/j.jhep.2015.08.011

Figures

Figure 1. Regions of interest (ROI) were delineated in the IVIM images with a b value of 10 s/mm2 Three ROIs were manually drawn at each anatomic location (head, body, and tail) of the pancreas on the slice containing the maximum amount of pancreatic parenchyma. (a) Three ROIs were manually drawn at the head of the pancreas. (b) The ROIs were manually drawn at the body and tail of the pancreas, respectively. The area of each ROI was 70 mm2 to 100 mm2.

Figure 2. Clinical characteristics of all subjects involved in the final analysis

Figure 3.Box-and-whisker plot with individual data points of the (a) ADCslow, (b) ADCfast, and (c) f values between control and cirrhotic groups

Figure 4.Correlations between IVIM-derived pancreatic parameters and Child-Pugh classification (a) ADCslow; (b) ADCfast; (c) f.

Figure 5.Box-and-whisker plot with individual data points of the (a) ADCslow, (b) ADCfast, and (c) f values among different severity of cirrhotic according to the Child-Pugh classification “ns” = statistically non-significant.

Proc. Intl. Soc. Mag. Reson. Med. 32 (2024)
1357
DOI: https://doi.org/10.58530/2024/1357