Introduction

Liver transplant evaluation is essential for assessing graft condition and identifying complications during the post-transplant period. Liver transplantation remains an important treatment option for patients with terminal chronic diffuse liver diseases. When cadaveric organs are unavailable, a right lobe liver transplant from a living relative can provide an alternative transplantation option.

A right lobe liver transplant offers several anatomical advantages. The right lobe has a consistent arterial and portal blood supply, while the larger diameter of the right hepatic artery can make vascular anastomosis more convenient. The configuration of the right lobe can also provide suitable placement within the recipient’s abdominal cavity.

Because complications may develop during different stages after transplantation, effective liver transplant monitoring is important. Dynamic assessment can help evaluate the liver transplant parenchyma, vessels, and intrahepatic bile ducts.

Nonlinear scanning (NLS) was investigated as a method for liver transplant evaluation and post-transplant monitoring. The objective was to identify NLS criteria that could be used to evaluate the condition of a right lobe liver transplant at different stages after transplantation.

Materials and Methods

The study included 70 patients who underwent right lobe liver transplantation from a living relative donor. The follow-up period ranged from one month to 6.5 years, with an average follow-up period of approximately 23.5 months.

Comprehensive NLS was performed using a Metatron-4027 device with a high-frequency generator and specialized software for three-dimensional visualization of the liver.

The liver transplant evaluation protocol included assessment of:

• Liver transplant parenchyma
• Hepatic and portal vessels
• Intrahepatic bile ducts
• Post-transplant structural changes
• Vascular complications
• Biliary complications

NLS-ultramicroscanning, spectral-entropic analysis (SEA), and NLS-ultramicroangiography were used during the examination. These techniques were used to evaluate morphological characteristics of hepatic tissue and vessels.

The first NLS examination was performed after surgery in the intensive care unit. During the first postoperative week, NLS was performed daily. During the second week, examinations were performed every second day when the post-transplant course was positive. Subsequent monitoring continued weekly until hospital discharge.

After discharge, liver transplant monitoring was performed approximately every three to four months, or more frequently when clinically indicated.

Results of Liver Transplant Evaluation

The study established criteria for liver transplant evaluation based on the condition of the transplant parenchyma, blood vessels, and intrahepatic bile ducts.

The intensity of parenchymal chromogeneity in an uncomplicated post-transplant period was generally equal to or slightly higher than that of the native left liver lobe.

The observed parenchymal changes were divided into diffuse, regional, and focal changes.

Diffuse Parenchymal Changes

Diffuse increases in right lobe transplant parenchymal chromogeneity were detected during the late post-transplant period in 5 patients, representing 7.1% of the study group.

These changes were associated with transplant dysfunction. Increased transaminase, cholestatic enzyme, and bilirubin levels were also observed.

This finding indicates that liver transplant evaluation may help identify changes associated with graft dysfunction when combined with clinical and laboratory assessment.

Regional Parenchymal Changes

Regional changes were identified in 3 recipients during the early post-transplant period and in another 3 recipients during the late post-transplant period.

The changes involved areas of liver segments VI and VII. These regional changes were not associated with the development of transplant dysfunction and were considered possible consequences of regional blood circulation disorders.

Further investigation was considered necessary to clarify the significance of these regional changes.

Focal Parenchymal Changes

Focal changes of the right lobe liver transplant were detected in 3 patients during the late post-transplant period.

In these cases, the focal changes represented acute abscesses and were accompanied by increased chromogeneity.

The identification of these focal changes through liver transplant evaluation helped identify possible causes of fever and increased cytolysis and cholestasis enzymes and contributed to treatment planning.

Vascular Complications

An important part of liver transplant monitoring is the evaluation of hepatic and portal blood vessels.

NLS-ultramicroangiography detected signs of hepatic artery thrombosis in one patient during the early postoperative period.

Hepatic artery stenosis was diagnosed in one patient during the early postoperative period and in another patient during the late postoperative period. The NLS findings were supported by SEA results.

Non-occlusive portal vein thrombosis was diagnosed in one patient during the early postoperative period. The finding involved the posterior branch of the right portal vein.

Portal vein stenosis was also identified in the region of the portal anastomosis.

Inferior vena cava stenosis was diagnosed in one recipient during the early postoperative period.

These findings demonstrate the importance of vascular assessment during liver transplant evaluation, particularly during the early postoperative period.

Biliary Complications

Biliary complications represented an important part of the findings in the study.

Signs of biliary hypertension, including intrahepatic bile duct involvement and increased chromogeneity, were detected in 23 patients during the early postoperative period. Moderate changes were identified in most of these patients, while significant changes were found in a smaller number.

During the late postoperative period, intrahepatic bile duct involvement was detected in 46 recipients, representing 65.7% of the study group.

The study identified biliary anastomotic strictures as an important cause of late postoperative biliary complications. Biliary reconstructions were performed in 8 patients because of biliary anastomosis strictures.

Therefore, liver transplant monitoring should include careful assessment of the intrahepatic bile ducts and biliary anastomosis.

Discussion

The study proposed that regional changes in transplant parenchymal chromogeneity should be distinguished from diffuse and focal parenchymal changes during NLS-based liver transplant evaluation.

Diffuse parenchymal changes were observed in 7.1% of patients during the late postoperative period and were associated with transplant dysfunction.

Regional parenchymal changes were observed in both early and late postoperative periods. These changes were not associated with transplant dysfunction in the observed patients and may have been related to regional blood circulation disorders.

Focal parenchymal changes were associated with acute abscesses and helped identify the possible causes of fever and biochemical abnormalities.

The study also found that NLS could identify vascular abnormalities including hepatic artery thrombosis, hepatic artery stenosis, portal vein thrombosis, portal vein stenosis, and inferior vena cava stenosis.

Biliary complications were particularly important during the late post-transplant period. Intrahepatic bile duct involvement and biliary anastomotic strictures represented major findings during long-term liver transplant monitoring.

Conclusion

Integrated NLS may provide a useful approach for liver transplant evaluation during different stages of the post-transplant period.

The evaluation can include three-dimensional scanning, NLS-ultramicroscanning with spectral-entropic analysis, and NLS-ultramicroangiography.

According to the study, NLS can be used to assess liver transplant parenchyma, vascular structures, and intrahepatic bile ducts. It may also help identify complications such as transplant dysfunction, hepatic artery thrombosis, portal vein abnormalities, and biliary complications.

Regular liver transplant monitoring may therefore support early identification of post-transplant abnormalities and help clinicians evaluate changes over time.

The study particularly emphasizes the potential role of NLS in monitoring intrahepatic bile ducts and detecting biliary complications after liver transplantation.