Preoperative volume calculation of the hepatic venous draining areas with multi-detector row CT in adult living donor liver transplantation: impact on surgical procedure

Segmental analysis of liver cirrhosis with different etiologies: a study based on iodine mixed imaging in port-venous phase

BACKGROUND

Computed tomography (CT) in port-venous phase can display the intra-hepatic vessels, and may provide the possibility for segment function evaluation for cirrhosis.

PURPOSE

To assess the value of iodine mixed imaging of dual-source dual-energy CT in port-venous phase in segmental evaluation of liver cirrhosis with different etiologies.

MATERIAL AND METHODS

Patients diagnosed with liver cirrhosis were enrolled. Patients without cirrhosis were included as a control group. Each patient underwent iodine-contrast enhanced multi-phase dual-energy CT scanning. Parameters were analyzed by SPSS, version 22.0, and Medcalc.

RESULTS

In total, 256 patients were investigated, including 114 Child-Pugh A, 51 Child-Pugh B, 41 Child-Pugh C and 50 control patients. Total iodine content (ICt)/body surface area (BSA) in the cirrhosis group was significantly lower than the control group (P < 0.05) and the standardized-iodine parameter (SI) of each segment decreased with cirrhosis progression. In Child-Pugh A and B, SI increased more significantly in the caudal and lateral segment in A (alcholism) than in the V (virus-related) and N (non-alcoholic steatohepatitis) groups (P < 0.001). ICt/BSA showed the best diagnosis power of cirrhosis with an area under the curve of 0.765, sensitivity of 76.0% and specificity of 71.8%.

CONCLUSION

Blood flow compensated in the left lateral and caudal lobe in the early stage of liver cirrhosis. The compensation in alcoholism in the middle and early stages is significantly higher than that of V and N cirrhosis. Iodine mixed imaging in portal phase may provide the possibility of an incremental value in segmented blood flow perfusion and functional evaluation of liver cirrhosis on a morphological basis.

A Hepatectomy Based on a Hybrid Concept of Portal Perfusion of Anterior Segment and Venous Drainage Area of Superior Right Hepatic Vein

BACKGROUND

Right hepatic vein sometimes could not be a reliable landmark between the anterior and posterior segment. The aim of this study was to clarify the portal perfusion area of the anterior segment and to propose a less invasive hepatectomy based on both the portal perfusion and the hepatic venous drainage.

METHODS

Three-dimensional computerized tomography images of 66 patients were constructed. A case, in which the perfusion area of the anterior segment crossed over superior right hepatic vein (SRHV), was called as SRHV-inclusion. It was defined as inclusion of more than 1 cm of the proximal site of SRHV surrounded by the portal perfusion area of the anterior segment.

RESULTS

SRHV-inclusion was observed in 26%. The cases with large inferior right hepatic vein (IRHV) had more frequent SRHV-inclusion (47%). The elderly patient with hepatic disorder, who had hepatocellular carcinoma near the root of the SRHV, underwent a less invasive hepatectomy (anterior segment + SRHV drainage area) resulting in the preservation of the IRHV.

CONCLUSIONS

The perfusion area of the anterior segment crossed over SRHV in one fourth of patients in the study. Our proposed less invasive hepatectomy based on a hybrid concept might be an alternative operative procedure other than right hepatectomy.

Impact of the Inferior Right Hepatic Veins on Right Liver Lobe Regeneration in Living-Donor Liver Transplant: 3-Dimensional Computed Tomography Scan Analyses in Donors and Recipients

OBJECTIVES

The presence of an inferior right hepatic vein significantly modifies the outflow pattern of the right liver and may have an impact on graft regeneration.

MATERIALS AND METHODS

Study patients were donors and recipients with 3-dimensional computed tomography scan simulation. We studied the physiologic impact of the inferior right hepatic veins on right liver regeneration in donors of left lobe grafts (step1; n = 60 patients) and the efficacy of a inferior right hepatic vein reconstruction policy based on a vessel caliber > 5 mm criteria in recipients of right liver grafts (step 2; n = 38 patients).

RESULTS

In step 1, the regeneration rate at 1 month was comparable between future liver remnants with inferior right hepatic vein (regeneration rate of 28.3%) and without inferior right hepatic vein (regeneration rate of 30.2%). In step 2, at 3 months after living-donor liver transplant, we observed no significant differences in regeneration rates among grafts anatomically without an inferior right hepatic vein (regeneration rate of 60.7%), grafts with an inferior right hepatic vein but no reconstruction (regeneration rate of 64.9%), and grafts with an inferior right hepatic vein and its reconstruction (regeneration rate of 68.1%). Within the latter subgroup, grafts with a dominant inferior right hepatic vein showed a greater regeneration of the anterior sector with inversion of the anterior-to-posterior sector regeneration ratio compared with right hepatic vein-dominant grafts (inferior right hepatic vein-dominant vs right hepatic vein-dominant showed anterior sector regeneration rates of 85.7% vs 52.1%; P = .02; anterior/posterior sector regeneration ratio was 2.3 vs 0.6, respectively; P = .04).

CONCLUSIONS

The reconstruction policy for inferior right hepatic vein with caliber > 5 mm is effective but should be implemented with computed tomography scan simulation. Right lobe grafts with a dominant inferior right hepatic vein are at higher risk of impaired regeneration due to expected large volumes of hepatic venous congestion if the middle hepatic veins tributaries or the inferior right hepatic veins are not reconstructed and an increased rate of right hepatic vein complications.

Mixed Imaging on Port-Venous Phase of Contrast-Enhanced Dual-Source Dual-Energy Computed Tomography: A Measurement Method Based on Couinaud Segments

OBJECTIVE

The aim of this study was to evaluate the changes of the iodine value quantified on the Couinaud segments measured in port-venous phase using the iodine-mixed technique of contrast-enhanced dual-source dual-energy computed tomography (CT) scanning in different Child-Pugh stages of hepatitis B-induced liver cirrhosis.

METHODS

Patients clinically diagnosed with hepatitis B-induced cirrhosis were prospectively engaged in our study. Each patient underwent multiphase iodine agent contrast-enhanced dual-source dual-energy CT scanning, and then the iodine-mixed imaging of port-venous phase was postprocessed. Iodine concentration was obtained for each segment based on the Couinaud segments. The volume of each segment and the total of the liver were measured and calculated using the postprocessing software of volume. All the cirrhosis patients were grouped into 3 subgroups based on the Child-Pugh stage method. Patients without cirrhosis were engaged for the control group. The iodine concentration, volume, and iodine storage among groups were analyzed by SPSS version 19.0. Single energy was used for the nonenhanced phase scanning, which was used for the radiation dosage comparison with dual-energy CT scanning.

RESULTS

Two hundred three patients were ultimately enrolled in our study, including 148 patients with cirrhosis (Child A, 69; Child B, 51; Child C, 28) and 55 patients without cirrhosis as control subjects. The total volume and iodine storage of cirrhosis group were smaller than those of the control group (P < 0.001). Compared with the control group, the iodine concentration in each segment decreased with progression of cirrhosis. The volume, iodine concentration, and iodine storage of the right hepatic lobe and left medial segment decreased with cirrhosis severity (P < 0.001). There was no significant difference in the volume of right hepatic lobe between Child C group and Child B group, whereas the iodine storage of Child C group was lower than that of Child B group (P < 0.05). The volume and iodine storage of left lateral segment increased with the progression of liver cirrhosis in the Child A and Child B groups (P < 0.05), whereas there was no statistical difference between the Child B and Child C groups, and the iodine storage in the Child C group was lower than that of the Child B group (P < 0.05). The radiation dose of dual-energy scanning was lower than that of single-energy scanning (P < 0.001). The iodine concentration 1.512 mg/mL on the left medial segment reached the most optimal evaluation on cirrhosis, with a sensitivity of 100%, specificity of 0.722, and area under the curve of 0.914.

CONCLUSIONS

Iodine concentration in portal phase measurement can evaluate and reflect the severity of cirrhosis. Iodine content segmental quantification can analyze the changes of the liver storage with a progression of cirrhosis. Dual-energy scanning reduced the radiation damage in patients and is valuable for a further study and clinical application.

Morphometric changes in liver cirrhosis: aetiological differences correlated with progression

OBJECTIVE

To evaluate the morphometric changes in liver cirrhosis using multidetector CT volumetry and to analyse the differences in morphometric changes among different aetiologies and stages of cirrhosis.

METHODS

Each portal segment with the respective proportion relative to total liver volume was measured in 54 patients without cirrhosis as a control (male/female, 29/25; 62.4 ± 7.6 years) and 250 patients with cirrhosis (male/female, 172/78; 64.6 ± 9.2 years) related to hepatitis virus infection (n = 96), alcoholism (n = 88) and non-alcoholic steatohepatitis (NASH) (n = 66). 149 patients were classified as patients with Child-Pugh Class A, 57 patients as patients with Class B and 44 patients as patients with Class C. The Kruskal-Wallis test was used for statistical analysis (p < 0.05).

RESULTS

Cirrhosis associated with all aetiologies commonly showed atrophy of the medial and anterior segments and right lobe and hypertrophy of the lateral segment and caudate lobe compared with the control (p < 0.05). In Child-Pugh Class A, hypertrophy of the caudate lobe progressed more in alcoholism and NASH than in virus-related aetiologies (p < 0.001). Hypertrophy of the lateral segment and atrophy of the medial and anterior segments and right lobe progressed less in NASH than in cases with virus related and alcoholic cirrhosis (p < 0.001). In patients with Class B, these differences were less prominent than in those with Class A (p < 0.001). In Class C, no significant differences were noted in any segment, regardless of aetiology (p > 0.05).

CONCLUSION

Morphometric changes of cirrhosis display different patterns according to aetiology. Differences between aetiologies would decrease with progression of cirrhosis.

ADVANCES IN KNOWLEDGE

Morphometric changes of cirrhosis display different patterns according to aetiology. Differences between aetiologies would decrease with progression of cirrhosis.

[Specific considerations in living-donor liver transplantation]

INTRODUCTION

Due to the limited number of cadaver donors, adult living liver donor transplantation became an alternative for liver transplantation. During living liver donor transplantation, the safety and uncomplicated recovery of the donor are as important as the appropriate volume and weight of the donated graft. The middle hepatic vein causes a significant dilemma, due to the special anatomical position. The reconstruction of the middle hepatic vein branches supplying S5, S8 is suggested when the anatomically right liver lobe is transplanted.

AIM

The aim of the present study was to investigate the requirements of the reconstruction of middle hepatic vein and to give an accurate description about the discrepancy between the portal vein in- and outflow.

METHOD

The authors analyzed the liver anatomic characteristics of 130 donors undergoing living liver donor transplantation with the use of MeVis software. The so-called porto-hepatic disparity index (shift) was introduced.

RESULTS

The right hepatic vein was dominant in 64.6% of all cases, while the left hepatic vein was never observed to be dominant. The territories of V5 and V8 were responsible for the 33.2±8.9% of the right hepatic lobe area. The correlation between portal venous territory and vein dominancy were as follows: R2 = 0.7811 in the left liver lobe; R² = 0.5463 in the area of middle hepatic vein and R² = 0.5843 in the case of the right hepatic vein. The average value of the shift was 28.2%.

CONCLUSIONS

The differences among the pattern of portal in- and hepatic outflow is an important issue that should be taken into consideration when deciding the necessity for reconstruction of the middle hepatic vein.

Evaluation of living liver donors using contrast enhanced multidetector CT - The radiologists impact on donor selection

Background

Living donor liver transplantation (LDLT) is a valuable and legitimate treatment for patients with end-stage liver disease. Computed tomography (CT) has proven to be an important tool in the process of donor evaluation. The purpose of this study was to evaluate the significance of CT in the donor selection process.

Methods

Between May 1999 and October 2010 170 candidate donors underwent biphasic CT. We retrospectively reviewed the results of the CT and liver volumetry, and assessed reasons for rejection.

Results

89 candidates underwent partial liver resection (52.4%). Based on the results of liver CT and volumetry 22 candidates were excluded as donors (31% of the cases). Reasons included fatty liver (n = 9), vascular anatomical variants (n = 4), incidental finding of hemangioma and focal nodular hyperplasia (n = 1) and small (n = 5) or large for size (n = 5) graft volume.

Conclusion

CT based imaging of the liver in combination with dedicated software plays a key role in the process of evaluation of candidates for LDLT. It may account for up to 1/3 of the contraindications for LDLT.

Quantitative measurement of radiofrequency volumetric tissue reduction by multidetector CT in patients with inferior turbinate hypertrophy

OBJECTIVE

To objectively assess the efficacy of radiofrequency thermal ablation of inferior turbinate hypertrophy.

METHODS

Thirty-five patients with nasal obstruction secondary to inferior turbinate hypertrophy were prospectively enrolled. Radiofrequency energy was delivered to four sites in each inferior turbinate. Patients were evaluated before and 8 weeks after intervention. Subjective evaluation of nasal obstruction was performed using a visual analogue scale (VAS), and objective evaluation of the turbinate volume reduction was calculated using multidetector CT. Volumetric measurements of the preoperative inferior turbinate were compared with postoperative values on both sides.

RESULTS

The great majority of patients (91.4%) exhibited subjective postoperative improvement. Mean obstruction (VAS) improved significantly from 7.45±1.48 to 3.54±1.96. Significant turbinate volume reduction was achieved by the surgery on both right and left sides [(preoperative vs. postoperative, right: 6.55±1.62cm(3) vs. 5.10±1.47cm(3), (P<0.01); left: 6.72±1.53cm(3) vs. 5.00±1.37cm(3), (P<0.01)] respectively.

CONCLUSION

Radiofrequency is a safe and effective surgical procedure in reducing turbinate volume in patients with inferior turbinate hypertrophy. Multidetector CT is an objective method of assessment in detecting radiofrequency turbinate volume reduction.

In vivo validation of a therapy planning system for laser-induced thermotherapy (LITT) of liver malignancies

PURPOSE

In situ ablation is increasingly being used for the treatment of liver malignancies. The application of these techniques is limited by the lack of a precise prediction of the destruction volume. This holds especially true in anatomically difficult situations, such as metastases in the vicinity of larger liver vessels. We developed a three-dimensional (3D) planning system for laser-induced thermotherapy (LITT) of liver tumors. The aim of the study was to validate the system for calculation of the destruction volume.

METHODS

LITT (28 W, 20 min) was performed in close contact to major hepatic vessels in six pigs. After explantation of the liver, the coagulation area was documented. The liver and its vascular structures were segmented from a pre-interventional CT scan. Therapy planning was carried out including the cooling effect of adjacent liver vessels. The lesions in vivo and the simulated lesions were compared with a morphometric analysis.

RESULTS

The volume of lesions in vivo was 6,568.3 ± 3,245.9 mm(3), which was not different to the simulation result of 6,935.2 ± 2,538.5 mm(3) (P = 0.937). The morphometric analysis showed a sensitivity of the system of 0.896 ± 0.093 (correct prediction of destructed tissue). The specificity was 0.858 ± 0.090 (correct prediction of vital tissue).

CONCLUSIONS

A 3D computer planning system for the prediction of thermal lesions in LITT was developed. The calculation of the directional cooling effect of intrahepatic vessels is possible for the first time. The morphometric analysis showed a good correlation under clinical conditions. The pre-therapeutic calculation of the ablation zone might be a valuable tool for procedure planning.

Hepatic vessel segmentation for 3D planning of liver surgery experimental evaluation of a new fully automatic algorithm

RATIONALE AND OBJECTIVES

The aim of this study was to identify the optimal parameter configuration of a new algorithm for fully automatic segmentation of hepatic vessels, evaluating its accuracy in view of its use in a computer system for three-dimensional (3D) planning of liver surgery.

MATERIALS AND METHODS

A phantom reproduction of a human liver with vessels up to the fourth subsegment order, corresponding to a minimum diameter of 0.2 mm, was realized through stereolithography, exploiting a 3D model derived from a real human computed tomographic data set. Algorithm parameter configuration was experimentally optimized, and the maximum achievable segmentation accuracy was quantified for both single two-dimensional slices and 3D reconstruction of the vessel network, through an analytic comparison of the automatic segmentation performed on contrast-enhanced computed tomographic phantom images with actual model features.

RESULTS

The optimal algorithm configuration resulted in a vessel detection sensitivity of 100% for vessels > 1 mm in diameter, 50% in the range 0.5 to 1 mm, and 14% in the range 0.2 to 0.5 mm. An average area overlap of 94.9% was obtained between automatically and manually segmented vessel sections, with an average difference of 0.06 mm(2). The average values of corresponding false-positive and false-negative ratios were 7.7% and 2.3%, respectively.

CONCLUSIONS

A robust and accurate algorithm for automatic extraction of the hepatic vessel tree from contrast-enhanced computed tomographic volume images was proposed and experimentally assessed on a liver model, showing unprecedented sensitivity in vessel delineation. This automatic segmentation algorithm is promising for supporting liver surgery planning and for guiding intraoperative resections.

Preoperative 3D volumetric analysis for liver congestion applied in a patient with hilar cholangiocarcinoma

BACKGROUND AND AIMS

Postoperative hepatic failure preceded by insufficient remnant liver function is one of the major causes of mortality. The aim of this article was to present the usefulness of preoperative three-dimensional volumetric analysis applied in liver resection to avoid congestion in the remnant liver.

CASE REPORT

The patient was a 45-year-old man with hilar cholangiocarcinoma. After bilateral percutaneous biliary transhepatic drainage, left hepatic lobectomy combined with total caudectomy was planned. Large inferior right hepatic vein (IRHV) and middle right hepatic vein (MRHV) was demonstrated by multidetector row computed tomography. By analyzing with liver simulation software, total liver volume and the remnant volume were 2,519.6 and 1,849.3 cm(3), respectively. The drainage volume of each vein was as follows: middle hepatic vein = 337.5 cm(3) (18.7%, ratio to the remnant right lobe); right hepatic vein = 627.9 cm(3) (34.8%); MRHV = 187.0 cm(3) (10.4%); IRHV = 651.9 cm(3) (36.1%). If we dissect both MRHV and IRHV, 46.5% of the remnant liver becomes congested. We planned to preserve these two veins. Operation was successfully performed without congestion. This modality provides a precise image of the intrahepatic structure and enables us to evaluate the congested area. This is important for a patient with a marginal amount of remnant liver, in which even a small congestion leads to a fatal consequence.

Evaluation of standard liver volume formulae for Chinese adults

AIM: To evaluate different standard liver volume (SLV) formula and verify the applicability of the formulae for Chinese adults.

METHODS: Data from 70 cases of living donor liver transplantation (LDLT) performed at our transplantation centers between January 2008 and April 2009 were analyzed. SLV was estimated using our recently reported formula [the Chengdu formula: SLV (mL) = 11.5 × body weight (kg) + 334] and other reported formulae used for Chinese adults. Actual intraoperative liver volumes were obtained from a review of the patients’ medical records.

RESULTS: The actual right liver volume was not significantly different from the estimated right liver volume determined by the Chengdu formula, but was significantly smaller than estimates using the Heinemann, Urata, Vauthey, and Lee formulae (P < 0.01), and significantly larger than estimates using the Fan formula (P < 0.05).

CONCLUSION: The Chengdu formula was demonstrated to be reliable by its application in LDLT.

Liver segmentation from computed tomography scans: a survey and a new algorithm

OBJECTIVE

In the recent years liver segmentation from computed tomography scans has gained a lot of importance in the field of medical image processing since it is the first and fundamental step of any automated technique for the automatic liver disease diagnosis, liver volume measurement, and 3D liver volume rendering.

METHODS

In this paper we report a review study about the semi-automatic and automatic liver segmentation techniques, and we describe our fully automatized method.

RESULTS

The survey reveals that automatic liver segmentation is still an open problem since various weaknesses and drawbacks of the proposed works must still be addressed. Our gray-level based liver segmentation method has been developed to tackle all these problems; when tested on 40 patients it achieves satisfactory results, comparable to the mean intra- and inter-observer variation.

CONCLUSIONS

We believe that our technique outperforms those presented in the literature; nevertheless, a common test set with its gold standard traced by experts, and a generally accepted performance measure are required to demonstrate it.

Portal vein segmentation of a 3D-planning system for liver surgery--in vivo evaluation in a porcine model

BACKGROUND

Computer systems allow the planning of complex liver operations. The segmentation of intrahepatic vessels builds the basis for the calculation of liver segments and resection proposals. For surgical use, it is essential to know the capabilities and limitations of the segmentation. The aim of this study was to determine the sensitivity and precision of the portal vein segmentation of a computer planning system for liver surgery in vivo.

METHODS

Segmentations were performed with the software system HepaVision on computed tomography (CT) scan data of domestic pigs. An in situ corrosion cast of the portal vein served as the gold standard. The segmentation results of the portal vein and the corrosion cast were compared with regard to sensitivity, precision, and amount of short-circuit segmentations.

RESULTS

The methodology demonstrated high resolution ex situ. The in vivo sensitivity of the portal vein segmentation was 100% for vessels of more than 5 mm in diameter and 82% for vessels of 3-4 mm. All segment branches were detected as well as 84% of the first subsegment branches with a diameter of more than 3 mm. The precision of the system was 100% for segment branches and 89% for the first subsegment vessels. The amount of internal short-circuit segmentations was less than 3.0%. No external short-circuits were found.

CONCLUSION

The system has a high precision and sensitivity under clinical conditions. The segmentation is suitable for portal vein branches of the first and second order and for vessels of >/=3 mm in diameter.