Radiology of Infectious Diseases

LETTER TO THE EDITOR
Year
: 2021  |  Volume : 8  |  Issue : 3  |  Page : 130--132

Magnetic resonance cholangiopancreatography evaluation of the biliary tract in hepatic alveolar echinococcosis before autotransplantation


Jian Wang1, Bo Ren2, Aierken Aikebaier1, - Ailixire3, Wenya Liu1,  
1 Imaging Center, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, China
2 Student, Xinjiang Medical University, Urumqi, China
3 Beijing Advanced Innovation Centre for Biomedical Engineering, Beihang University, Beijing, China

Correspondence Address:
Wenya Liu
Imaging Center, The First Affiliated Hospital of Xinjiang Medical University, Urumqi
China




How to cite this article:
Wang J, Ren B, Aikebaier A, Ailixire -, Liu W. Magnetic resonance cholangiopancreatography evaluation of the biliary tract in hepatic alveolar echinococcosis before autotransplantation.Radiol Infect Dis 2021;8:130-132


How to cite this URL:
Wang J, Ren B, Aikebaier A, Ailixire -, Liu W. Magnetic resonance cholangiopancreatography evaluation of the biliary tract in hepatic alveolar echinococcosis before autotransplantation. Radiol Infect Dis [serial online] 2021 [cited 2022 Jul 6 ];8:130-132
Available from: http://www.ridiseases.org/text.asp?2021/8/3/130/342624


Full Text



To the Editor,

Hepatic alveolar echinococcosis (HAE) is a parasitic disease caused by Echinococcus multilocularis larvae. HAE growth characteristics are similar to those of malignant tumors; therefore, HAE is also called “worm cancer.” Complete resection of HAE is still the first-choice therapy; however, the radical resection rate is low owing to invasion into blood vessels and bile ducts.[1] Ex vivo liver resection and autotransplantation (ELRA) is a promising surgical method for unresectable patients.[2] With the accumulation of surgical cases and postoperative follow-up data, the treatment effect of ELRA has been proven satisfactory. The preoperative accurate assessment of hepatic vascular structure is a key step in ELRA. Accurate assessment of bile duct anatomical structure and invasion can effectively avoid postoperative bile leakage and cholestatic hepatocyte injury. However, there are few studies on the bile duct imaging features before ELRA. In this letter, we share our experience using magnetic resonance cholangiopancreatography (MRCP) to evaluate biliary tract structure before ELRA.

Fifty-three patients with end-stage HAE were enrolled in this study from December 2012 to November 2017, comprising 37 males and 16 females, ranging in age from 18 to 63 years (average: 42 years). All patients underwent ELRA, and MRCP was performed before surgery. The MRCP sequences comprised free-breathing navigator-triggered three-dimensional MRCP and breath-hold two-dimensional MRCP. Image analysis was performed by two attending doctors with more than 5 years' diagnostic experience in imaging diagnosis. The three- and two-dimensional MRCP images were combined in the film reading, and the evaluators were blinded to the patients' operation results. Differences in opinions were resolved by consensus. In accordance with Li's research,[3] we used bile duct truncation and occlusion as the evaluation criteria for bile duct invasion. ELRA can be divided into five types based on the segment of residual normal liver parenchyma, as follows: Type 1 (left lobe), Type 2 (right posterior lobe), Type 3 (right lobe), Type 4 (left medial lobe), and Type 5 (left lobe + right posterior lobe).

In this study, we evaluated the dilatation degree of the bile duct in the HAE cases. Dilatation was classified as mild (25 cases, diameter: ≤5 mm); moderate (5 cases, diameter: >5 mm and ≤8 mm); severe (3 cases, diameter: >8 mm); and no dilatation (20 cases). The imaging features of HAE on MRCP were as follows: The internal signal of HAE lesions was uneven and mixed, with the necrotic area in the lesion showing high signal intensity and the solid part of the lesion showing low, equal, or high signal intensity. Multiple small vesicles of different sizes were seen in the HAE lesions, with high signal intensity on MRCP. Compressed bile ducts were displaced, with stenosis, and the signal intensity in the bile duct lumen was decreased. If the bile duct was truncated, it was considered invaded. The number of patients with Type 1–5 ELRA was 38, 3, 6, 4, and 2, respectively. The data for the MRCP diagnostic accuracy and the intraoperative findings are shown in [Table 1].{Table 1}

The invasive growth pattern of HAE leads to bile duct wall injury or direct infiltration into the bile duct, which results in atrophy, collapse, and occlusion of the biliary tract. In addition, HAE can cause an immune response and stimulate the proliferation of inflammatory cells, which leads to an inflammatory reaction in the biliary system and edema of the bile duct wall and further aggravates biliary stricture.[4] After ELRA, biliary complications are the main factors affecting patients' long-term results and quality of life.

ELRA may be performed using several approaches for bile duct reconstruction, and it is often necessary to reconstruct level 2 and 3 intrahepatic bile ducts. Therefore, it is necessary to visualize the intrahepatic bile duct tree comprehensively and stereoscopically. We recommend MRCP because this imaging method can reconstruct the intrahepatic bile ducts and show the three-dimensional spatial relationships between the intrahepatic bile ducts and the lesions. MRCP avoids the ionizing radiation associated with computed tomography cholangiography and the issue of nondilated bile ducts. MRCP can also effectively avoid the failure risk and complications associated with endoscopic retrograde cholangiopancreatography and other invasive techniques. Therefore, MRCP plays an increasingly important role in the preoperative evaluation of HAE.

The results of our study showed that MRCP was highly accurate for locating biliary strictures. MRCP displays both the dilated and nondilated bile ducts, which is an improvement over computed tomography cholangiography. MRCP also better displays the three-dimensional spatial relationships between the bile ducts and lesions. However, studies have shown that the accuracy of MRCP for determining bile duct invasion is relatively low (86.79%). MRCP highlights the water signal in the bile ducts, and signals are weaker for the bile duct wall and surrounding tissue structures. After studying 53 ELRA cases that underwent MRCP, we confirm that bile duct interruption and bile ducts running through the lesion or along the edge of the lesion were not reliable signs of bile duct wall and intraluminal invasion. There remains a lack of characteristic diagnostic criteria for HAE bile duct invasion using MRCP.

Some scholars suggest combining MRCP and intraoperative cholangiography[5] to increase the diagnostic accuracy. Enhanced cholangiography with the MR-specific contrast agents, mangafodipir trisodium[6] and gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid,[7] can be used to display both the bile duct tree and the tissue structures around the bile ducts. A more accurate method to evaluate bile duct invasion is anticipated.

Ethic statement

The study was conducted in accordance with the Declaration of Helsinki, and the protocol was approved by the Ethics Committee of The First Affiliated Hospital of Xinjiang Medical University. Signed informed consent was obtained from all patients before any study-specific procedure was performed.

Acknowledgment

We thank Jane Charbonneau, DVM, from Liwen Bianji (Edanz) (www.liwenbianji.cn/) for editing the English text of a draft of this manuscript.

Ethic statement

Not applicable.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

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