CT volumetry of the liver: where does it stand in clinical practice?

Dynamic liver volume change in predicting hepatic decompensation and long-term effects of stereotactic body radiation therapy

BACKGROUND AND AIM

This study aimed to investigate the association between liver volume change and hepatic decompensation and compare the risk of hepatic decompensation in patients with liver cirrhosis (LC) and hepatocellular carcinoma (HCC) who underwent stereotactic body radiation therapy (SBRT).

METHODS

A retrospective review of SBRT-treated HCC and compensated LC without HCC patients was conducted. Liver volume was measured using auto-segmentation software on liver dynamic computed tomography scans. The decompensation event was defined as the first occurrence of refractory ascites, esophageal variceal bleeding, hepatic encephalopathy, or spontaneous bacterial peritonitis. We evaluated the association between the rate of liver volume decrease and hepatic decompensation and compared decompensation events between the SBRT and LC cohorts using propensity score matching.

RESULTS

A total of 138 patients from the SBRT cohort and 488 from the LC cohort were analyzed. The rate of liver volume decrease was associated with the risk of decompensation events in both cohorts. The 3-year rate of decompensation events was significantly higher in the group with a liver volume decreasing rate > 7%/year compared with the group with a rate < 7%/year. In the propensity score-matched cohort, the 3-year rate of decompensation events after a single session of SBRT was not significantly different from that in the LC cohort.

CONCLUSIONS

The rate of liver volume decrease was significantly associated with the risk of hepatic decompensation in both HCC patients who received SBRT and LC patients. A single session of SBRT for HCC did not result in a higher decompensation rate compared with LC.

Significance of radiation therapy in the myxoid round-cell liposarcoma treatment regimen

BACKGROUND AND PURPOSE

Because myxoid liposarcomas are more radiosensitive than other soft tissue sarcomas, there have been several reports of 50 Gy preoperative radiation therapy combined with surgery, but the wound complication rate is reportedly high. We have performed preoperative irradiation at a reduced dose of 40 Gy and definitive radiation therapy for unresectable cases. This study aimed to report the tumor reduction rate and oncological results with a reduced dose of preoperative irradiation and the outcome of definitive irradiation for unresectable cases.

MATERIALS AND METHODS

Forty-one patients with myxoid liposarcoma treated in our institution between 2002 and 2021 were included. We examined the tumor volume shrinkage rate with preoperative radiation, compared complications and oncological outcomes between preoperative radiation and surgery-only cases, and investigated the prognosis and tumor shrinkage of definitive radiation cases.

RESULTS

The total dose irradiated was 40 Gy except in two cases. The mean tumor volume reduction rate was 52.0%. A decreased dose of preoperative radiation did not worsen clinical outcomes with fewer complications. The total dose of definitive radiation was approximately 60 Gy. The mean tumor volume reduction rate was 55.0%. The tumor shrinkage maintenance rate was 100% in a median follow-up period of 50.5 months.

CONCLUSION

Preoperative radiation therapy for myxoid liposarcoma near vital organs is a good approach because even with a reduced dose of 40 Gy, significant tumor reduction and excellent results were achieved. Definitive radiation therapy is the recommended treatment for older patients with serious comorbidities or inoperable patients.

Evaluation of Various Methods of Liver Measurement in Comparison to Volumetric Segmentation Based on Computed Tomography

Background: A reliable assessment of liver volume, necessary before transplantation, remains a challenge. Our work aimed to assess the differences in the evaluation and measurements of the liver between independent observers and compare different formulas calculating its volume in relation to volumetric segmentation. Methods: Eight researchers measured standard liver dimensions based on 105 abdominal computed tomography (CT) scans. Based on the results obtained, the volume of the liver was calculated using twelve different methods. An independent observer performed a volumetric segmentation of the livers based on the same CT examinations. Results: Significant differences were found between the formulas and in relation to volumetric segmentation, with the closest results obtained for the Heinemann et al. method. The measurements of individual observers differed significantly from one another. The observers also rated different numbers of livers as enlarged. Conclusions: Due to significant differences, despite its time-consuming nature, the use of volumetric liver segmentation in the daily assessment of liver volume seems to be the most accurate method.

Correlation between the liver transection line localization and future liver remnant hypertrophy in associating liver partition and portal vein ligation for staged hepatectomy

Background and aims

Colorectal liver metastases (CRLMs) represent the most prevalent form of secondary liver tumors, and insufficient future liver remnant (FLR) often leads to unresectability. To tackle this challenge, various methods for stimulating liver hypertrophy have been developed including portal vein embolization (PVE), associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) and the newest one, liver venous deprivation (LVD). ALPPS was thoroughly studied over the last decade and it has been shown to induce rapid and intensive FLR hypertrophy. The objective of this study was to assess whether the localization of the liver transection line during the initial stage of ALPPS correlates with the degree of FLR hypertrophy.

Methods

A retrospective, multicentric study was conducted, and we analyzed all consecutive patients with CRLMs who underwent ALPPS over the eight-year period. Patients were categorized into two groups based on the type of resection-right trisectionectomy (ERH) or right hemihepatectomy (RH) respectively. The degree of hypertrophy (DH), its correlation with FLR and postoperative outcomes were assessed.

Results

The cohort consisted of 136 patients (72 in the ERH group and 64 in the RH group). Baseline characteristics, hypertrophy interval, and total liver volume showed no significant differences between the groups. DH was greater in the ERH group (83.2% vs. 62.5%, p = 0.025). A strong negative correlation was observed between FLR volume and DH in both groups. Postoperative outcomes and one-year survival were comparable between the groups.

Conclusions

FLR hypertrophy is influenced by the localization of the liver transection line in ALPPS. Furthermore, correlation analysis indicated that a smaller estimated FLR is associated with greater DH. No statistical difference in outcomes was noted between the groups.

Opportunistic Extraction of Quantitative CT Biomarkers: Turning the Incidental Into Prognostic Information

The past two decades have seen a significant increase in the use of CT, with a corresponding rise in the mean population radiation dose. This rise in CT use has caused improved diagnostic certainty in conditions that were not previously routinely evaluated using CT, such as headaches, back pain, and chest pain. Unused data, unrelated to the primary diagnosis, embedded within these scans have the potential to provide organ-specific measurements that can be used to prognosticate or risk-profile patients for a wide variety of conditions. The recent increased availability of computing power, expertise and software for automated segmentation and measurements, assisted by artificial intelligence, provides a conducive environment for the deployment of these analyses into routine use. Data gathering from CT has the potential to add value to examinations and help offset the public perception of harm from radiation exposure. We review the potential for the collection of these data and propose the incorporation of this strategy into routine clinical practice.

Understanding the role of radiologists in complex treatment decisions for patients with hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common primary malignant tumor of the liver and represents a significant global health burden. Management of HCC can be challenging due to multiple factors, including variable expectations for treatment outcomes. Several treatment options are available, each with specific eligibility and ineligibility criteria, and are provided by a multidisciplinary team of specialists. Radiologists should be aware of the types of treatment options available, as well as the criteria guiding the development of individualized treatment plans. This awareness enables radiologists to contribute effectively to patient-centered multidisciplinary tumor boards for HCC and play a central role in reassessing care plans when the treatment response is deemed inadequate. This comprehensive review aims to equip radiologists with an overview of HCC staging systems, treatment options, and eligibility criteria. The review also discusses the significance of imaging in HCC diagnosis, treatment planning, and monitoring treatment response. Furthermore, we highlight the crucial branch points in the treatment decision-making process that depend on radiological interpretation.

Recent advances in computerized imaging and its vital roles in liver disease diagnosis, preoperative planning, and interventional liver surgery: A review

The earliest and most accurate detection of the pathological manifestations of hepatic diseases ensures effective treatments and thus positive prognostic outcomes. In clinical settings, screening and determining the extent of a pathology are prominent factors in preparing remedial agents and administering appropriate therapeutic procedures. Moreover, in a patient undergoing liver resection, a realistic preoperative simulation of the subject-specific anatomy and physiology also plays a vital part in conducting initial assessments, making surgical decisions during the procedure, and anticipating postoperative results. Conventionally, various medical imaging modalities, e.g., computed tomography, magnetic resonance imaging, and positron emission tomography, have been employed to assist in these tasks. In fact, several standardized procedures, such as lesion detection and liver segmentation, are also incorporated into prominent commercial software packages. Thus far, most integrated software as a medical device typically involves tedious interactions from the physician, such as manual delineation and empirical adjustments, as per a given patient. With the rapid progress in digital health approaches, especially medical image analysis, a wide range of computer algorithms have been proposed to facilitate those procedures. They include pattern recognition of a liver, its periphery, and lesion, as well as pre- and postoperative simulations. Prior to clinical adoption, however, software must conform to regulatory requirements set by the governing agency, for instance, valid clinical association and analytical and clinical validation. Therefore, this paper provides a detailed account and discussion of the state-of-the-art methods for liver image analyses, visualization, and simulation in the literature. Emphasis is placed upon their concepts, algorithmic classifications, merits, limitations, clinical considerations, and future research trends.

T1 relaxation time analysis in predicting hepatic dysfunction and prognosis in patients with HCC undergoing transarterial chemoembolization

OBJECTIVE

To evaluate the value of T1 mapping in predicting hepatic dysfunction and prognosis in patients with hepatocellular carcinoma (HCC) undergoing transarterial chemoembolization (TACE).

MATERIAL AND METHODS

100 consecutive patients with treatment-naive HCC treated with TACE were prospectively analyzed. Clinical, laboratory, and MRI parameters (liver and tumor T1 relaxation times (T1L, T1T)) before and/or following TACE were measured and calculated. Clinical parameters included the Child-Turcotte-Pugh (CTP) classification, Barcelona Clinic Liver Cancer Classification (BCLC) criteria, and albumin-bilirubin (ALBI) score. Laboratory parameters were the gold standard for hepatic dysfunction. T1L and T1T were combined by stepwise multivariate logistic regression to yield a T1-related probability index (T1com) for further analysis. Study endpoints included hepatic dysfunction and progression-free survival (PFS) rate.

RESULTS

38 patients (38%) were diagnosed with hepatic dysfunction following TACE. There was no significant difference in clinical parameters between the groups with and without hepatic dysfunction. Logistic regression analysis showed that T1L and T1T were independent risk factors for assessing hepatic dysfunction. T1com showed a better AUC than T1L and T1T (0.81 vs. 0.76 and 0.69, P = 0.007 and 0.006). Patients with low T1com (≤0.42) showed a better median PFS than patients with high T1com (>0.42) (167.0 vs. 215.9 days, P = 0.010). In comparison, CTP, BCLC, and ALBI scores were not statistically significant in predicting PFS in HCC patients treated with TACE (P > 0.05).

CONCLUSION

Compared with widely used clinical parameters, T1 was more capable of predicting hepatic dysfunction after TACE. Stratification of patients with HCC undergoing TACE according to T1 may help clinicians to develop treatment strategies in preventing the occurrence of hepatic dysfunction and improving individual prognoses.

Handheld photoacoustic imaging of indocyanine green clearance for real-time quantitative evaluation of liver reserve function

Preoperative assessment of liver function reserve (LFR) is essential for determining the extent of liver resection and predicting the prognosis of patients with liver disease. In this paper, we present a real-time, handheld photoacoustic imaging (PAI) system-based noninvasive approach for rapid LFR assessment. A linear-array ultrasound transducer was sealed in a housing filled with water; its front end was covered with a plastic wrap. This PAI system was first implemented on phantoms to confirm that the photoacoustic (PA) intensity of indocyanine green (ICG) in blood reflects the concentration of ICG in blood. In vivo studies on normal rabbits and rabbits with liver fibrosis were carried out by recording the dynamic PA signal of ICG in their jugular veins. By analyzing the PA intensity-time curve, a clear difference was identified in the pharmacokinetic behavior of ICG between the two groups. In normal rabbits, the mean ICG clearance rate obtained by PAI at 15 min after administration (PAI-R15) was below 21.6%, whereas in rabbits with liver fibrosis, PAI-R15 exceeded 62.0% because of poor liver metabolism. The effectiveness of the proposed method was further validated by the conventional ICG clearance test and pathological examination. Our findings suggest that PAI is a rapid, noninvasive, and convenient method for LFR assessment and has immense potential for assisting clinicians in diagnosing and managing patients with liver disease.

ICG clearance test based on photoacoustic imaging for assessment of human liver function reserve: An initial clinical study

Liver function reserve (LFR) plays an extensive and important role in patients with liver disease. Indocyanine green (ICG) clearance test is the standard diagnostic approach for LFR evaluation which was performed by spectrophotometry or pulse dye densitometry (PDD). Spectrophotometry is the gold standard, it's invasive and not real-time. PDD is non-invasive, but accuracy of PDD is controversial. Taken spectrophotometry as the reference standard, this study investigated the accuracy of photoacoustic imaging (PAI) method for LFR assessment and compared to PDD in healthy volunteers. The results demonstrated a strong correlation between PAI method and spectrophotometry (r = 0.9649, p < 0.0001). No significant difference was shown in ICG clearance between PAI and spectrophotometry method (rate constant k1 vs. k2, 0.001158 +-0.00042 vs. 0.001491 +- 0.00045, p = 0.0727; half-life t1 vs. t2, 601.2 s vs. 474.4 s, p = 0.1450). These results indicated that PAI may be valuable as a noninvasive, accurate diagnostic tool for LFR assessment in human.

CT volume analysis in living donor liver transplantation: accuracy of three different approaches

OBJECTIVES

The aim of this retrospective study is to compare and evaluate accuracy of three different approaches of liver volume quantification in living donor transplantations.

METHODS

This is a single-center, retrospective study of 60 donors. The total and right lobe liver volumes were analyzed in the portal-venous phase by two independent radiologists who estimated the volumes using manual, semi-automated and automated segmentation methods. The measured right lobe liver volume was compared to the real weight of the graft after back-table examinations.

RESULTS

The mean estimated overall liver volume was 1164.4 ± 137.0 mL for manual, 1277.4 ± 190.4 mL for semi-automated and 1240.1 ± 108.5 mL for automated segmentation. The mean estimated right lobe volume was 762.0 ± 122.4 mL for manual, 792.9 ± 139.9 mL for semi-automated and 765.4 ± 132.7 mL for automated segmentation. The mean graft weight was 711.2 ± 142.9 g. The manual method better correlated with the graft weight (r = 0.730) in comparison with the semi-automated (r = 0.685) and the automated (r = 0.699) methods (p < 0.001). The mean error ratio in volume estimation by each application was 12.7 ± 16.6% for manual, 17.1 ± 17.3% for semi-automated, 14.7 ± 16.8% for automated methods. There was a statistically significant difference between the mean error ratio of the manual and the semi-automated segmentations (p = 0.017), and no statistically significant difference between the manual and the automated applications (p = 0.199).

CONCLUSION

Volume analysis application better correlates with graft weight, but there is no obvious difference between correlation coefficients of all three methods. All three modalities had an error ratio, of which the semi-automated method showed the highest value.

CRITICAL RELEVANCE STATEMENT

Volume analysis application was more accurate, but there is no drastic difference between correlation coefficients of all three methods.

Liver Transplant in Patients with Hepatocarcinoma: Imaging Guidelines and Future Perspectives Using Artificial Intelligence

Hepatocellular carcinoma is the most common primary malignant hepatic tumor and occurs most often in the setting of chronic liver disease. Liver transplantation is a curative treatment option and is an ideal solution because it solves the chronic underlying liver disorder while removing the malignant lesion. However, due to organ shortages, this treatment can only be applied to carefully selected patients according to clinical guidelines. Artificial intelligence is an emerging technology with multiple applications in medicine with a predilection for domains that work with medical imaging, like radiology. With the help of these technologies, laborious tasks can be automated, and new lesion imaging criteria can be developed based on pixel-level analysis. Our objectives are to review the developing AI applications that could be implemented to better stratify liver transplant candidates. The papers analysed applied AI for liver segmentation, evaluation of steatosis, sarcopenia assessment, lesion detection, segmentation, and characterization. A liver transplant is an optimal treatment for patients with hepatocellular carcinoma in the setting of chronic liver disease. Furthermore, AI could provide solutions for improving the management of liver transplant candidates to improve survival.

Protocol for the CoNoR Study: A prospective multi-step study of the potential added benefit of two novel assessment tools in colorectal liver metastases technical resectability decision-making

INTRODUCTION

Liver resection is the only curative treatment for colorectal liver metastases (CLM). Resectability decision-making is therefore a key determinant of outcomes. Wide variation has been demonstrated in resectability decision-making, despite the existence of criteria. This paper summarises a study protocol to evaluate the potential added value of two novel assessment tools in assessing CLM technical resectability: the Hepatica preoperative MR scan (MR-based volumetry, Couinaud segmentation, liver tissue characteristics and operative planning tool) and the LiMAx test (hepatic functional capacity).

METHODS AND ANALYSIS

This study uses a systematic multistep approach, whereby three preparatory workstreams aid the design of the final international case-based scenario survey:Workstream 1: systematic literature review of published resectability criteria.Workstream 2: international hepatopancreatobiliary (HPB) interviews.Workstream 3: international HPB questionnaire.Workstream 4: international HPB case-based scenario survey.The primary outcome measures are change in resectability decision-making and change in planned operative strategy, resulting from the novel test results. Secondary outcome measures are variability in CLM resectability decision-making and opinions on the role for novel tools.

ETHICS AND DISSEMINATION

The study protocol has been approved by a National Health Service Research Ethics Committee and registered with the Health Research Authority. Dissemination will be via international and national conferences. Manuscripts will be published.

REGISTRATION DETAILS

The CoNoR Study is registered with ClinicalTrials.gov (registration number NCT04270851). The systematic review is registered on the PROSPERO database (registration number CRD42019136748).

High-resolution MR imaging with gadoxetate disodium for the comprehensive evaluation of potential living liver donors

OBJECTIVE

Several major transplantation centers have used composite multimodality evaluation for the preoperative evaluation of potential living liver donors. This approach can be time-consuming and, although rare, can cause complications. We aimed to demonstrate the clinical feasibility of our comprehensive preoperative MR protocol for the preoperative assessment of living liver donor candidates instead of composite multimodality evaluation.

MATERIALS AND METHODS

Thirty-five consecutive living liver donor candidates underwent multiphasic liver CT and comprehensive donor protocol MR examinations for preoperative evaluation in a single large-volume liver transplantation (LT) center. Three blinded abdominal radiologists reviewed the CT and MR images for vascular and biliary variations. The strength of agreement between CT and MR angiography was assessed using the kappa index. The detection rate of biliary anatomical variations was calculated. The sensitivity and specificity for detecting significant steatosis (>5%) were calculated. The estimated total volume and right lobe volumes measured by MR volumetry were compared with the corresponding CT volumetry measurements using the intraclass correlation coefficient (ICC).

RESULTS

Among the 35 patients, 26 underwent LT. The measurement of agreement showed a moderate to substantial agreement between CT and MR angiography interpretations (kappa values, 0.47-0.79; p < 0.001). Combining T2-weighted and T1-weighted MR cholangiography techniques detected all biliary anatomical variations in 9 of the 26 patients. MR-proton density fat fraction showed a sensitivity of 100% (3/3) and a specificity of 91.3% (21/23) for detecting pathologically determined steatosis (>5%). MR volumetry reached an excellent agreement with CT volumetry (reviewers 1 and 2: ICC, 0.92; 95% CI, 0.84-0.96).

CONCLUSION

Our one-stop comprehensive liver donor MR imaging protocol can provide complete information regarding hepatic vascular and biliary anatomies, hepatic parenchymal quality, and liver volume for living liver donor candidates and can replace composite multimodality evaluation.

Estimation of post-therapeutic liver reserve capacity using 99mTc-GSA scintigraphy prior to carbon-ion radiotherapy for liver tumors

BACKGROUND

There is currently no established imaging method for assessing liver reserve capacity prior to carbon-ion radiotherapy (CIRT) for liver tumors. In order to perform safe CIRT, it is essential to estimate the post-therapeutic residual reserve capacity of the liver.

PURPOSE

To evaluate the ability of pre-treatment 99mTc-galactosyl human serum albumin (99mTc-GSA) scintigraphy to accurately estimate the residual liver reserve capacity in patients treated with CIRT for liver tumors.

MATERIALS AND METHODS

This retrospective study evaluated patients who were performed CIRT for liver tumors between December 2018 and September 2020 and underwent 99mTc-GSA scintigraphy before and 3 months after CIRT, and gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI within 1 month before CIRT were evaluated. The maximal removal rate of 99mTc-GSA (GSA-Rmax) was analyzed for the evaluation of pre-treatment liver reserve capacity. Then, the GSA-Rmax of the estimated residual liver (GSA-RL) was calculated using liver SPECT images fused with the Gd-EOB-DTPA-enhanced MRI. GSA-RL before CIRT and GSA-Rmax at 3 months after CIRT were compared using non-parametric Wilcoxon signed-rank test and linear regression analysis.

RESULTS

Overall, 50 patients were included (mean age ± standard deviation, 73 years ± 11; range, 29-89 years, 35 men). The median GSA-RL was 0.393 [range, 0.057-0.729] mg/min, and the median GSA-Rmax after CIRT was 0.369 [range, 0.037-0.780] mg/min (P = .40). The linear regression equation representing the relationship between the GSA-RL and GSA-Rmax after CIRT was y = 0.05 + 0.84x (R2 = 0.67, P < .0001). There was a linear relationship between the estimated and actual post-treatment values for all patients, as well as in the group with impaired liver reserve capacity (y = - 0.02 + 1.09x (R2 = 0.62, P = .0005)).

CONCLUSIONS

99mTc-GSA scintigraphy has potential clinical utility for estimating the residual liver reserve capacity in patients undergoing carbon-ion radiotherapy for liver tumors.

TRIAL REGISTRATION

UMIN000038328, https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000043545 .

New Imaging Techniques

The chapter discusses the advancement of new imaging techniques, the role of imaging in CCA diagnosis, anatomical and morphological classification, ultrasound screening of CCA, ultrasound findings of MF-CCA, PI-CCA, ID-CCA, the use of CT in CCA diagnosis, staging and treatment planning, CT volumetry and estimation of future liver remnant, post-treatment follow-up and surveillance, MRI imaging, Positron Emission Tomography (PET)/CT, limitations to contrast studies and resolution, internal receivers for CCA imaging, and in vitro imaging of CCA.

Preoperative estimation of hemi-liver volume using standard liver volume and portal vein diameter ratio in living donor liver transplantation

Backgrounds/Aims

Although body surface area (BSA)-based standard liver volume (SLV) formulae have been used for living donor liver transplantation and hepatic resection, hemi-liver volume (HLV) is needed more frequently. HLV can be assessed using right or left portal vein diameter (RPVD or LPVD). The aim of this study was to validate the reliability of using portal vein diameter ratio (PVDR) for assessing HLV in living liver donors.

Methods

This study included 92 living liver donors (59 males and 33 females) who underwent surgery between January 2020 and December 2020. Computed tomography (CT) images were used for measurements.

Results

Mean age of donors was 35.5 ± 7.2 years. CT volumetry-measured total liver volume (TLV), right HLV, left HLV, and percentage of right HLV in TLV were 1,442.9 ± 314.2 mL, 931.5 ± 206.4 mL, 551.4 ± 126.5 mL, and 64.6% ± 3.6%, respectively. RPVD, LPVD, and main portal vein diameter were 12.2 ± 1.5 mm, 10.0 ± 1.3 mm, and 15.3 ± 1.7 mm, respectively (corresponding square values: 149.9 ± 36.9 mm², 101.5 ± 25.2 mm², and 237.2 ± 52.2 mm², respectively). The sum of RPVD² and LPVD² was 251.1 ± 56.9 mm². BSA-based SLV was 1,279.5 ± 188.7 mL (error rate: 9.1% ± 14.4%). SLV formula- and PVDR-based right HLV was 760.0 ± 130.7 mL (error rate: 16.2% ± 13.3%).

Conclusions

Combining BSA-based SLV and PVDR appears to be a simple method to predict right or left HLV in living donors or split liver transplantation.

Leberchirurgie 4.0 - OP-Planung, Volumetrie, Navigation und Virtuelle Realität

Durch die Optimierung der konservativen Behandlung, die Verbesserung der bildgebenden Verfahren und die Weiterentwicklung der Operationstechniken haben sich das operative Spektrum sowie der Maßstab für die Resektabilität in Bezug auf die Leberchirurgie in den letzten Jahrzehnten deutlich verändert.

Dank zahlreicher technischer Entwicklungen, insbesondere der 3-dimensionalen Segmentierung, kann heutzutage die präoperative Planung und die Orientierung während der Operation selbst, vor allem bei komplexen Eingriffen, unter Berücksichtigung der patientenspezifischen Anatomie erleichtert werden.

Neue Technologien wie 3-D-Druck, virtuelle und augmentierte Realität bieten zusätzliche Darstellungsmöglichkeiten für die individuelle Anatomie. Verschiedene intraoperative Navigationsmöglichkeiten sollen die präoperative Planung im Operationssaal verfügbar machen, um so die Patientensicherheit zu erhöhen.

Dieser Übersichtsartikel soll einen Überblick über den gegenwärtigen Stand der verfügbaren Technologien sowie einen Ausblick in den Operationssaal der Zukunft geben.

Volumetric assessment of hepatic grafts using a light detection and ranging system for 3D scanning: Preliminary data

BACKGROUND

Liver transplantation has evolved into a safe life-saving operation and remains the golden standard in the treatment of end stage liver disease. The main limiting factor in the application of liver transplantation is graft shortage. Many strategies have been developed in order to alleviate graft shortage, such as living donor partial liver transplantation and split liver transplantation for adult and pediatric patients. In these strategies, liver volume assessment is of paramount importance, as size mismatch can have severe consequences in the success of liver transplantation.

AIM

To evaluate the safety, feasibility, and accuracy of light detection and ranging (LIDAR) 3D photography in the prediction of whole liver graft volume and mass.

METHODS

Seven liver grafts procured for orthotopic liver transplantation from brain deceased donors were prospectively measured with an LIDAR handheld camera and their mass was calculated and compared to their actual weight.

RESULTS

The mean error of all measurements was 17.03 g (range 3.56-59.33 g). Statistical analysis of the data yielded a Pearson correlation coefficient index of 0.9968, indicating a strong correlation between the values and a Student’s t-test P value of 0.26. Mean accuracy of the measurements was calculated at 97.88%.

CONCLUSION

Our preliminary data indicate that LIDAR scanning of liver grafts is a safe, cost-effective, and feasible method of ex vivo determination of whole liver volume and mass. More data are needed to determine the precision and accuracy of this method.

Liver venous deprivation versus associating liver partition and portal vein ligation for staged hepatectomy for colo-rectal liver metastases: a comparison of early and late kinetic growth rates, and perioperative and oncological outcomes

BACKGROUND

Different techniques have been developed to optimize the Future Liver Remnant (FLR). Associated liver partition and portal vein ligation for staged hepatectomy (ALPPS) and liver venous deprivation (LVD) have shown the higher hypertrophy rates, but their place in clinical practice is still debated.

METHODS

Thirty-two consecutive ALPPS and LVD procedures for CRLM performed between December 2015 and December 2019 were included. This retrospective study evaluated kinetic growth rates (KGR) as primary outcome, and perioperative and oncological outcomes as secondary endpoints.

RESULTS

A total of 17 patients underwent LVD before surgery, whereas 15 underwent ALPPS. On early evaluation (7 vs 9 days, respectively), KGR did not differ between ALPPS and LVD cohort (0.8% per day vs 0.3% per day, p = 0.70; 23 cc/day vs 26 cc/day, p = 0.31). Late evaluation (21 vs 9 days) showed a KGR significantly decreased in the LVD group (0.6% per day vs 0.2% per day, p = 0.21; 20 cc/day vs 10 cc/day p = 0.02). Mean FLR-V increase was comparable in the two groups (60% vs 49%, p 0.32). Successful resection rate was 100% and 94% in LVD and ALPPS group, respectively. The hospital stay (p < 0.0001) and severe complications rate (p = 0.05) were lower after LVD. One and 3-years overall survival (OS) were 72,7% and 27,4% in the ALPSS group, versus 81,3% and 54,7% in LVD group (p = 0.10). The Median DFS was comparable between both techniques (6.1 months and 5.9 respectively, p = 0.66).

CONCLUSIONS

LVD and ALPPS shows similar KGR during the early period following preparation as well as similar survival outcomes. Hospital stay and severe complications are lower after LVD.

Splenic Volume, an Easy-To-Use Predictor of HCC Late Recurrence for HCC Patients After Hepatectomy

Purpose

The high recurrence rate of hepatocellular carcinoma (HCC) has a poor impact on the quality of life and survival time of patients. Especially for late recurrence, poor data are available in analysis. We aim to evaluate whether the splenic volume (SV) measured from preoperative CT images could predict late recurrence in HCC patients after hepatectomy.

Patients and Methods

A cohort of 300 HCC patients hospitalized at Xiangya Hospital of Central South University between January 2015 and June 2018 was retrospectively analyzed. The SV was calculated by using automated volumetry software from preoperative CT images. A total of 300 HCC patients were separated into the early recurrence cohort (n=167), the late recurrence cohort (n=39), and the no recurrence cohort (n=94) according to whether there is a recurrence and the recurrence time. Univariate and multivariate Cox analyses were performed to identify the independent risk factors of both early and late recurrence.

Results

AFP, Microvascular invasion (MVI), satellitosis, and BCLC staging were independent risk factors of HCC early recurrence. Splenic volume (HR=1.003, 95%CI:1.001-1.005, P<0.001) was the only predictor of HCC late recurrence. Based on X-tile software, 133 non-early recurrence patients were divided into two groups according to SV: low SV (<165ml, n=45) and high SV (≥165ml, n= 88). The low SV group had a significantly better RFS compared with the high SV group (P=0.015). Nomogram was built on the base of SV to get the probability of 3-year RFS, 4-year RFS, and 5-year RFS.

Conclusion

In our study, we drew a conclusion that splenic volume was the only predictor of HCC late recurrence because of its association with portal hypertension and liver cirrhosis. High splenic volume often indicated a worse recurrence.

Undifferentiated Embryonal Sarcoma of the Liver Involving All Major Hepatic Veins Treated by Left Extended Trisectionectomy

Introduction

Over the past few years, liver surgery has been in constant evolution and gained many improvements that helped surgeons push limits further. A complex procedure such as left extended trisectionectomy, as described by Makuuchi in 1987, may be performed in selected cases.

Aim

Describe a case of successful resection of a huge bilobar liver sarcoma involving all hepatic veins from a young female patient, in which the blood outflow was preserved through an inferior right hepatic vein, leaving only segment 6 as liver remnant. Case Report. A 19-year-old female with a 3-month history of abdominal pain, vomiting, and weight loss was referred for our evaluation. CT scan and MRI revealed a heterogeneous and bulky expansive hepatic lesion, sparing only segment 6, with an estimated volume of 530 cm³, corresponding to a 1.2 FLR/BW ratio. The tumor involved the three major hepatic veins, but an inferior right hepatic vein was present, draining the spared segment 6. She was submitted to a left trisectionectomy extended to the caudate lobe and segment 7, including resection of all hepatic veins and lymphadenectomy of the hepatic pedicle. She was discharged on the 7th postoperative day without complications. The histopathological and immunohistochemical analysis demonstrated an undifferentiated embryonal sarcoma of the liver.

Conclusion

Inferior right hepatic vein-preserving left extended trisectionectomy is a safe and feasible procedure that should be performed by a hepatobiliary team experienced in major complex hepatectomies.

Accuracy and Efficiency of Right-Lobe Graft Weight Estimation Using Deep-Learning-Assisted CT Volumetry for Living-Donor Liver Transplantation

CT volumetry (CTV) has been widely used for pre-operative graft weight (GW) estimation in living-donor liver transplantation (LDLT), and the use of a deep-learning algorithm (DLA) may further improve its efficiency. However, its accuracy has not been well determined. To evaluate the efficiency and accuracy of DLA-assisted CTV in GW estimation, we performed a retrospective study including 581 consecutive LDLT donors who donated a right-lobe graft. Right-lobe graft volume (GV) was measured on CT using the software implemented with the DLA for automated liver segmentation. In the development group (n = 207), a volume-to-weight conversion formula was constructed by linear regression analysis between the CTV-measured GV and the intraoperative GW. In the validation group (n = 374), the agreement between the estimated and measured GWs was assessed using the Bland–Altman 95% limit-of-agreement (LOA). The mean process time for GV measurement was 1.8 ± 0.6 min (range, 1.3–8.0 min). In the validation group, the GW was estimated using the volume-to-weight conversion formula (estimated GW [g] = 206.3 + 0.653 × CTV-measured GV [mL]), and the Bland–Altman 95% LOA between the estimated and measured GWs was −1.7% ± 17.1%. The DLA-assisted CT volumetry allows for time-efficient and accurate estimation of GW in LDLT.

Impact of Pretransplantation CT on Liver Donation in Potential Deceased Organ Donors

BACKGROUND

Computed tomography (CT) is routinely used to determine the suitability of potential living donor liver transplants, providing important information about liver size, vascular anatomy, and the presence of other diseases that would preclude it from safe donation. CT is not routinely used, however, when evaluating eligible deceased organ donors after brain death, a group which comprises most orthotopic liver transplants. After the installation of a CT scanner at a local procurement facility, CTs have been performed on potential deceased organ donors and used, in conjunction with other evaluative protocols, to help direct donation decisions and assist in procurement procedures.

STUDY DESIGN

A retrospective analysis of data from 373 cases spanning 5 years was systematically collected and analyzed, including information pertaining to patient's medical histories, biopsy results, operative findings, and CT results.

RESULTS

CT findings directly impacted the directive decision-making process in 29% of cases in this patient cohort, likely an underestimate, and reliably evaluated important factors including variant vascular anatomy and the presence and severity of hepatic steatosis and cirrhosis.

CONCLUSION

Overall, this study suggests that CT has the potential to play a significant role in procurement procedures and the directive decision-making process, thereby improving the efficiency and accuracy by which potential deceased organ donors are evaluated.

Correlation between liver volume and liver weight in a cohort with chronic liver disease: a semiautomated CT-volumetry study

BACKGROUND

To estimate the optimal density coefficient for conversion of liver volume into liver weight in patients with chronic liver disease based on semiautomated CT-liver volumetry data and the histologic Ishak score of explanted liver.

METHODS

A total of 114 patients (39 female; age, 46±20 years) with chronic liver diseases who underwent liver transplantation between January 2010 and September 2020 were identified over a patient chart search at our institution and subsequently analyzed in retrospect. All patients had contrast-enhanced CT-examinations (mean, 24 days) to liver transplantation. Liver volume was calculated by a semiautomated software and results compared with the liver weight registered by the pathologist. Each explanted liver was histologically scored into six classes according to the Ishak classification where the categories were subgrouped based on recommendation of the pathologists into the following categories 0-3, 4-5 and 6.

RESULTS

Mean liver volume was 1,870±1,195, 1,162±679 and 1,278±510 mL for the categories 0-3, 4-5 and 6, respectively. Mean liver weight was 1,624±999, 1,082±669 and 1,346±559 g for the categories 0-3, 4-5 and 6, respectively. A coefficient of 0.92±0.22, 0.98±0.28 and 1.06±0.20 g/mL was found at best for conversion of liver volume into liver weight in these subgroups. Differences between Ishak-subgroups proved significant (0.002). In 4 patients with cystic liver disease, density coefficients varied significantly and were found generally lower compared to the other liver disorders.

CONCLUSIONS

Our results yielded significant differences between the density coefficients calculated along with the Ishak score and also for the subgroup with cystic liver disease.

Role of CT in Two-Stage Liver Surgery

Complete resection is the only potentially curative treatment for primary or metastatic liver tumors. Improvements in surgical techniques such as conventional two-stage hepatectomy (TSH) with portal vein embolization and ALPPS (associating liver partition and portal vein ligation for staged hepatectomy) promote hypertrophy of the future liver remnant (FLR), expanding resection criteria to include patients with widespread hepatic disease who were formerly not considered candidates for resection. Radiologists are essential in the multidisciplinary approach required for TSH. In particular, multidetector CT has a critical role throughout the various stages of this surgical process. The aims of CT before the first stage of TSH are to define the feasibility of surgery, assess the number and location of liver tumors in relation to relevant anatomy, and provide a detailed anatomic evaluation, including vascular and biliary variants. Volume calculation with CT is also essential to determine if the FLR is sufficient to avoid posthepatectomy liver failure. The objectives of CT between the first and second stages of TSH are to recalculate liver volumes (ie, assess FLR hypertrophy) and depict expected liver changes and complications that could modify the surgical plan or preclude the second stage of definitive resection. In this review, the importance of CT throughout different stages of TSH is discussed and key observations that contribute to surgical planning are highlighted. In addition, the advantages and limitations of MRI for detection of liver metastases and assessment of complications are briefly described. ^©RSNA, 2022.

Prediction of Liver Weight Recovery by an Integrated Metabolomics and Machine Learning Approach After 2/3 Partial Hepatectomy

Liver has an ability to regenerate itself in mammals, whereas the mechanism has not been fully explained. Here we used a GC/MS-based metabolomic method to profile the dynamic endogenous metabolic change in the serum of C57BL/6J mice at different times after 2/3 partial hepatectomy (PHx), and nine machine learning methods including Least Absolute Shrinkage and Selection Operator Regression (LASSO), Partial Least Squares Regression (PLS), Principal Components Regression (PCR), k-Nearest Neighbors (KNN), Support Vector Machines (SVM), Random Forest (RF), eXtreme Gradient Boosting (xgbDART), Neural Network (NNET) and Bayesian Regularized Neural Network (BRNN) were used for regression between the liver index and metabolomic data at different stages of liver regeneration. We found a tree-based random forest method that had the minimum average Mean Absolute Error (MAE), Root Mean Squared Error (RMSE) and the maximum R square (R²) and is time-saving. Furthermore, variable of importance in the project (VIP) analysis of RF method was performed and metabolites with VIP ranked top 20 were selected as the most critical metabolites contributing to the model. Ornithine, phenylalanine, 2-hydroxybutyric acid, lysine, etc. were chosen as the most important metabolites which had strong correlations with the liver index. Further pathway analysis found Arginine biosynthesis, Pantothenate and CoA biosynthesis, Galactose metabolism, Valine, leucine and isoleucine degradation were the most influenced pathways. In summary, several amino acid metabolic pathways and glucose metabolism pathway were dynamically changed during liver regeneration. The RF method showed advantages for predicting the liver index after PHx over other machine learning methods used and a metabolic clock containing four metabolites is established to predict the liver index during liver regeneration.

Computed Tomography-Measured Liver Volume Predicts the Risk of Hepatocellular Carcinoma Development in Chronic Hepatitis C Patients

AIM

In this retrospective cohort study, we evaluated the significance of liver volume in the prediction of hepatocellular carcinoma (HCC) in 277 chronic hepatitis C (CHC) patients who received dynamic computed tomography (CT) during surveillance.

METHODS

Liver volumes were measured on portal venous phase of CT images by using ImageJ software. Liver volume index, a ratio of the standard liver volume expected by weight and height to the measured liver volume, was calculated to adjust for normal variations. The cohort was randomly divided to derivation (n = 100) and validation sets (n = 177) for the generation of a liver volume-based Cox prediction model and validation of a liver volume-based nomogram, respectively.

RESULTS

The liver volume index was independent of weight or height, and it predicted further development of HCC (hazard ratio [HR] 16.30, 95% CI 6.70-39.62; p < 0.001). Liver cirrhosis, gamma-glutamyl transferase, and liver volume index were independent predictors of HCC, and nomogram-based prediction score from these three parameters identified high-risk patients at the cutoff of 110 in both derivation (p < 0.001) and validation cohort (p < 0.001).

CONCLUSION

Liver volume-based prediction model stratifies the risk of developing HCC in CHC patients whose initial dynamic CT study gave negative results.

Variations between the anatomical and functional distribution, based on 99m technetium -mebrofinate SPECT-CT scan, in patients at risk of post hepatectomy liver failure

BACKGROUND

The aim of the current study is to investigate the variations of anatomical (LV_Rem%) and functional remnant volumes (fLV_Rem%) and the dynamic uptake of Technetium-Mebrofinate (FRLF) measured from 99^m Technetium-Mebrofinate SPECT-CT scan (TMSCT) in patients at high risk of post-hepatectomy liver failure (PHLF).

METHODS

Variations in the measures of LV_Rem% and fLV_Rem% were assessed. The predictive accuracies of LV_Rem%, fLV_Rem% and FRLF with respect to PHLF were reported.

RESULTS

From the N = 92 scans performed, LV_Rem% and fLV_Rem% returned identical results in 15% of cases, and ±10 percentage points in 79% of cases. Some patients had larger discrepancies, with difference of >10 percentage points in 21% of cases. The difference was significant in those with primary liver cancers (-4.4 ± 9.2, p = 0.002). For the N = 29 patients that underwent surgery as planned on TMSCT, FRLF was a strong predictor of PHLF, with an AUROC of 0.83 (p = 0.005).

CONCLUSION

TMSCT is emerging as a useful modality in pre-operative assessment of patients undergoing major liver resection. For those with primary liver cancer, there is a significant variation in the anatomical and functional distributions that needs considered in surgical planning. Reduced FRLF, measured as the dynamic uptake in the future liver remnant, is a strong predictor of PHLF.

A simplified CT-volumetry method for the canine liver

Computed tomographic (CT) liver volumetry using the slice addition technique is an accurate, but a time-consuming method. Commonly used DICOM-viewing software only allows contouring of one area per image, which can be troublesome in the transverse plane as different lobes are separated. In this prospective, experimental, methods comparison study, we aimed to determine if hepatic contouring using sagittal reformatting and a reduced number of images would yield accurate results. Computed tomographic studies were performed in five canine cadavers and reviewed using sagittal reformatting. For each dog, the number of images that included the liver was used to create four stacks with progressively fewer images in which the liver would be contoured, each with the following median number of images: A: 60, B: 31, C: 16, and D: 9. Liver volume was calculated by three observers using the different stacks of images. After CT examination, the cadavers were dissected, the liver was removed, and its volume was determined by water displacement. Single score intraclass correlation coefficient was calculated to assess interobserver agreement. Kruskal-Wallis test was used to compare water displacement and CT-based volumes. There was excellent agreement between observers (intraclass correlation coefficient = 0.957; 95% confidence interval, 0.908-0.982, P < 0.0001). No significant difference was found between the volumes obtained by CT-volumetry using each of the stacks and the volumes obtained by water displacement. Using sagittally reformatted images and hepatic contouring in as few as nine images can be an accurate and simple method for CT-volumetry of the canine liver.

Predictive value of gadoxetic acid-enhanced MRI for posthepatectomy liver failure: a systematic review

Objectives

Effective and non-invasive biomarkers to predict and avoid posthepatectomy liver failure (PHLF) are urgently needed. This systematic review aims to evaluate the efficacy of gadoxetic acid–enhanced MRI-derived parameters as an imaging biomarker in preoperative prediction of PHLF.

Methods

A systematic literature search was performed in the databases of PubMed/Medline, Web of Science, Embase, and Cochrane Library up to 11 December 2020. Studies evaluating the incidence of PHLF on patients who underwent hepatectomy with preoperative liver function assessment using gadoxetic acid–enhanced MRI were included. Data was extracted using pre-designed tables. The Quality In Prognostic Studies (QUIPS) tool was adopted to evaluate the risk of bias.

Results

A total of 15 studies were identified for qualitative synthesis and most studies were marked as low to moderate risk of bias in each domain of QUIPS. The most commonly used parameter was relative liver enhancement or its related parameters. The reported incidence of PHLF ranged from 3.9 to 40%. The predictive sensitivity and specificity of gadoxetic acid–enhanced MRI parameters varied from 75 to 100% and from 54 to 93% in ten reported studies. A majority of the studies revealed that the gadoxetic acid–enhanced MRI parameter was a predictor for PHLF.

Conclusions

Gadoxetic acid–enhanced MRI showed a high predictive capacity for PHLF and represents a promising imaging biomarker in prediction of PHLF. Multicenter, prospective trials with large sample size and reliable, unified liver function parameters are required to validate the efficacy of individual liver function parameters.

Key Points

• There is an obvious heterogeneity of the published studies, not only in variance of MRI liver function parameters but also in indication and extent of the liver resection.

• Signal intensity (SI)–based parameters derived from gadoxetic acid–enhanced MRI are the commonly used method for PHLF prediction.

• Gadoxetic acid–enhanced MRI-derived parameters showed high predictive efficacy for PHLF and can potentially serve as a predictor for the incidence of PHLF.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00330-021-08297-8.

Lower Ratio of Liver Volume and Body Weight Is a Negative Predictor of Survival after Transjugular Intrahepatic Portosystemic Shunt

Transjugular intrahepatic portosystemic shunt (TIPS) is the most effective measure to treat complications of portal hypertension. However, liver function may deteriorate after TIPS. Predictors of liver function and outcome after TIPS are therefore important for management of TIPS patients. The study aimed to evaluate the impact of liver volume on transplant-free survival (TFS) after TIPS, as well as the evolution of liver volume and its relationship with liver function after TIPS. A retrospective analysis of all consecutive patients who underwent TIPS in a tertiary care university liver center between 2012 and 2017 (n = 216) was performed; n = 72 patients with complete prior and follow-up (FU) computed tomography (CT) imaging studies were included in the study. Volumetry of the liver was performed by a semi-automatic 9-lobe image segmentation algorithm at baseline and FU (FU 1: 90–180 d; FU 2: 180–365 d; FU 3: 365–545 d; FU 4: 545–730 d; FU 5: >730 d). Output variables were total liver volume (TLV, cm³), left liver volume (LLV, cm³), right liver volume (RLV, cm³) and TLV/body weight ratio. CT derived liver volumes were correlated with liver function tests, portosystemic pressure gradient (PPG) measurements and survival. To assess predictors of liver volume change over time we fitted linear mixed models. Kaplan–Meier analysis was performed and validated by matched pair analysis followed by Cox regression to determine independent prognostic factors for survival. The median TLV at baseline was 1507.5 cm³ (773.7–3686.0 cm³). Livers with higher baseline liver volumes and larger TLV/weight ratios retained their volume after an initial loss while smaller livers continuously lost volume after TIPS. At the first follow-up period (90–180 d post-TIPS) lower liver volumes and TLV/weight ratios were associated with higher bilirubin levels. Within the final multivariable model containing time (days since TIPS), baseline INR and baseline TLV, the average loss of liver volume was 0.74 mL per day after TIPS. Twelve-month overall transplant-free survival was 89% and median overall TFS was 33 months. The median TFS for a baseline TLV/body weight ratio > 20 was significantly higher compared with ≤20 (40.0 vs. 27.0 months, p = 0.010) while there were no differences regarding the indication for TIPS or etiology of liver disease in the matched pair analysis. Lower TLV/weight ratios before TIPS were associated with shorter TFS and should therefore be critically considered when selecting patients for TIPS. In addition, this study provides first evidence of an effect of TIPS on subsequent liver volume change and associated liver function.

Fully automated whole-liver volume quantification on CT-image data: Comparison with manual volumetry using enhanced and unenhanced images as well as two different radiation dose levels and two reconstruction kernels

OBJECTIVES

To evaluate the accuracy of fully automated liver volume quantification vs. manual quantification using unenhanced as well as enhanced CT-image data as well as two different radiation dose levels and also two image reconstruction kernels.

MATERIAL AND METHODS

The local ethics board gave its approval for retrospective data analysis. Automated liver volume quantification in 300 consecutive livers in 164 male and 103 female oncologic patients (64±12y) performed at our institution (between January 2020 and May 2020) using two different dual-energy helicals: portal-venous phase enhanced, ref. tube current 300mAs (CARE Dose4D) for tube A (100 kV) and ref. 232mAs tube current for tube B (Sn140kV), slice collimation 0.6mm, reconstruction kernel I30f/1, recon. thickness of 0.6mm and 5mm, 80-100 mL iodine contrast agent 350 mg/mL, (flow 2mL/s) and unenhanced ref. tube current 100mAs (CARE Dose4D) for tube A (100 kV) and ref. 77mAs tube current for tube B (Sn140kV), slice collimation 0.6mm (kernel Q40f) were analyzed. The post-processing tool (syngo.CT Liver Analysis) is already FDA-approved. Two resident radiologists with no and 1-year CT-experience performed both the automated measurements independently from each other. Results were compared with those of manual liver volume quantification using the same software which was supervised by a senior radiologist with 30-year CT-experience (ground truth).

RESULTS

In total, a correlation of 98% was obtained for liver volumetry based on enhanced and unenhanced data sets compared to the manual liver quantification. Radiologist #1 and #2 achieved an inter-reader agreement of 99.8% for manual liver segmentation (p<0.0001). Automated liver volumetry resulted in an overestimation (>5% deviation) of 3.7% for unenhanced CT-image data and 4.0% for contrast-enhanced CT-images. Underestimation (<5%) of liver volume was 2.0% for unenhanced CT-image data and 1.3% for enhanced images after automated liver volumetry. Number and distribution of erroneous volume measurements using either thin or thick slice reconstructions was exactly the same, both for the enhanced as well for the unenhanced image data sets (p> 0.05).

CONCLUSION

Results of fully automated liver volume quantification are accurate and comparable with those of manual liver volume quantification and the technique seems to be confident even if unenhanced lower-dose CT image data is used.

Intra- inter-observer repeatability in liver computed tomography volumetry in patients undergoing radioembolization simulation

PURPOSE

The careful evaluation of MDCT is an essential step for the treatment planning in pre-treatment imaging work-up for Trans-Arterial Radio Embolization (TARE). It may provide unique volumetric data (CTVs), which are information useful for an effective and safe TARE. The purpose of this study is to demonstrate that the radiographer is able to calculate CTVs of TARE simulation with the same precision as the interventional radiologist.

METHODS

This study retrospectively considers 17 consecutive patients (8 males, 9 females; mean age 66.3 ± 13.2 years) who underwent pre-treatment work-up for TARE, between May 2019 and February 2020 (trial ID:2234 - protocol). For each patient, four specific parameters are evaluated from MDCT achieved during treatment simulation: healthy liver volume (HLV), the whole hepatic parenchyma (THV = healthy liver and TTV = tumour) involved by TARE, and whole liver volume (WLV). Four independent observers-R1 (expert interventional radiologist), T1, T2, and T3 (radiographers, with different experiences in the field of interventional radiology)-are involved in the imaging analysed.

RESULTS

All the 4 observers detected the same number of hepatic lesion(s) per patient. Regarding the three radiographers, the intra-observer reliability for CTVs is very high 0.997 to 1.000 (95%CI). Also inter-observer reproducibility between radiographers is excellent regarding CTVs, 0.965 to 0.999 (95%CI). The accuracy of radiographer evaluation is very high 0.964 to 0.999 (95%CI).

CONCLUSIONS AND IMPLICATIONS FOR PRACTICE

The high intra- and inter-observer reproducibility shows that a properly trained radiographers might have the same accuracy as interventional radiologists, in assessing liver CTV data for planning TARE.

Comparison between preoperative two-dimensional shear wave elastography and indocyanine green clearance test for prediction of post-hepatectomy liver failure

Background

Post-hepatectomy liver failure (PHLF) is one of the most serious complications and major causes of liver resection mortality. The purpose of this study is to investigate and compare the performance of preoperative two-dimensional shear wave elastography (2D-SWE) and the indocyanine green (ICG) clearance test for the prediction of PHLF.

Methods

A total of 172 consecutive patients who were undergoing major liver resection were prospectively identified. Patients were evaluated by preoperative 2D-SWE and ICG clearance test. According to the International Study Group of Liver Surgery (ISGLS) recommendations, No PHLF, PHLF A, PHLF B, and PHLF C group classifications were defined. The differences in liver stiffness value (LSV) and ICG retention rate at 15 minutes (ICGR15) among the different PHLF classifications were investigated. The performance of LSV and ICGR15 for diagnosing different classifications of PHLF was compared.

Results

PHLF occurred in 43 (25.0%) patients, and 24 (14.0%) patients were grade A, 14 (8.1%) were grade B, and 5 (2.9%) were grade C. Both LSV and ICGR15 of the PHLF C group were significantly higher than those of the No PHLF group (P=0.025, P=0.001, respectively). According to univariate and multivariate logistic regression analysis, LSV and ICGR15 were significantly related to PHLF (P=0.051, P=0.084, respectively). For diagnosis of ≥ PHLF A, ≥ PHLF B, and ≥ PHLF C, the areas under the receiver operating characteristic curve (AUCs) for 2D-SWE were 0.624 [95% confidence interval (CI): 0.536-0.712, P=0.015], 0.699 (95% CI: 0.576-0.821, P=0.005), and 0.831 (95% CI: 0.737-0.925, P=0.01), respectively. The AUCs of the ICG clearance test were 0.631 (95% CI: 0.542-0.721, P=0.01), 0.570 (95% CI: 0.436-0.704, P=0.32), and 0.717 (95% CI: 0.515-0.920, P=0.098), respectively. The AUC of LSV for the diagnosis of ≥ PHLF A was comparable to that of ICGR15 (P=0.17). The AUCs of LSV were significantly higher than those of ICGR15 for the diagnosis of ≥ PHLF B (P=0.002) and C (P=0.038).

Conclusions

2D-SWE demonstrates the potential to aid in the prediction of the severity of PHLF. Our findings also suggest that the performance of 2D-SWE is better than the ICG clearance test.

Invasive aspergillosis in solid organ transplant patients: diagnosis, prophylaxis, treatment, and assessment of response

BACKGROUND

Invasive aspergillosis (IA) is a rare complication in solid organ transplant (SOT) recipients. Although IA has significant implications on graft and patient survival, data on diagnosis and management of this infection in SOT recipients are still limited.

METHODS

Discussion of current practices and limitations in the diagnosis, prophylaxis, and treatment of IA and proposal of means of assessing treatment response in SOT recipients.

RESULTS

Liver, lung, heart or kidney transplant recipients have common as well as different risk factors to the development of IA, thus each category needs a separate evaluation. Diagnosis of IA in SOT recipients requires a high degree of awareness, because established diagnostic tools may not provide the same sensitivity and specificity observed in the neutropenic population. IA treatment relies primarily on mold-active triazoles, but potential interactions with immunosuppressants and other concomitant therapies need special attention.

CONCLUSIONS

Criteria to assess response have not been sufficiently evaluated in the SOT population and CT lesion dynamics, and serologic markers may be influenced by the underlying disease and type and severity of immunosuppression. There is a need for well-orchestrated efforts to study IA diagnosis and management in SOT recipients and to develop comprehensive guidelines for this population.

Undifferentiated carcinoma of the liver in a 3-year-old girl treated by neoadjuvant chemotherapy and complete resection

INTRODUCTION

Undifferentiated carcinoma (UC) of the liver has only been reported in three adults in the English language literature and is so rare it has never been reported in a child. Our management is presented to improve knowledge of its treatment.

CASE PRESENTATION

A 3-year-old previously well Japanese girl was referred for further assessment/management of an abdominal mass. On examination an obvious right hypocostal mass was visible extending across the midline. Diagnostic imaging identified a 12.5 cm mass on the ventral surface of the liver containing multiple cystic lesions extending along Glisson's capsule with invasion to the portal vein. Open biopsy eventually led to a diagnosis of poorly differentiated or UC of the liver with embryonal features. Resection of hepatic segments 4b and 5 after a remarkable initial response to cisplatin/doxorubicin that shrank the tumor substantially, separating it from Glisson's capsule enabled total excision. Surgery was successful and tolerated well with unremarkable postoperative recovery. Unfortunately, ascites due to peritoneal carcinomatosis developed 4 months postoperatively and she died 5 months later.

CONCLUSION

The initial impressive response to neoadjuvant chemotherapy and successful surgery was unexpectedly fortuitous but inadequate for controlling such an aggressive malignancy. Our case demonstrates the value of neoadjuvant chemotherapy.

Role of residual liver volumetry and function in prediction of liver tolerability after transarterial chemoembolization for hepatocellular carcinoma in cirrhotic patients: deriving a clinical decision support score

Background

Transarterial chemoembolization (TACE) is the recommended treatment modality for non-resectable intermediate-stage hepatocellular carcinoma; however, this stage has wide variable levels of liver functions and tumor burden making a challenge as regards the tolerability of the functioning residual liver to this type of therapy. Further stratification of this intermediate stage may help the clinical decision for the suitability of TACE, so we tried to derive a clinical decision support tool to predict the tolerability of the functioning residual liver to TACE using pre-intervention liver reserve function and liver residual volume as well as tumor burden.

Results

Two hundred and fifty-two patients with non-resectable intermediate-stage hepatocellular carcinoma (HCC) were consecutively included in this cohort study; all patients were blindly followed up for 6 weeks after TACE for manifestation of liver decompensation. For univariate logistic regression analysis, the significant predictors were age, s.albumin, s.bilirubin, prothrombin concentration (PC), tumor volume (TV), residual liver volume (RLV), and residual to liver volumetric ratio (RLVR) (sig, 0.007, 0.000, 0.000, 0.000, 0.000, 0.002, and 0.000, respectively). Multivariate logistic regression analysis illustrated that s.albumin, s.bilirubin, PC, and RLVR were the most independent significant predictors (sig, 0.000 for all with adjusted OR 0.002, 22.692, 0.827, and 0.000, respectively). The discriminatory performance of our proposed decision support score (liver tolerability score) was evaluated using the receiver operating characteristics that identified two cutoff points (≤ 0.30 and ≥ 0.83) to rule out or rule in the possibility of liver decompensation after TACE, respectively (AUC, 0.942 and sig. 0.000). Liver tolerability score stratified the intermediate stage of HCC to 3 risk grades (low, medium, and high) with significant difference as regards hazard distribution.

Conclusion

Computed tomography image-based assessment of RLVR may have a possible role in predicting future tolerability of the functioning residual tissue to TACE of HCC. Liver tolerability score (LTS) could stratify the intermediate stage HCC to 3 risk grades, so LTS may have a role in clinical decision for the suitability of TACE for intermediate stage HCC.

Deep Learning Algorithm for Automated Segmentation and Volume Measurement of the Liver and Spleen Using Portal Venous Phase Computed Tomography Images

Objective

Measurement of the liver and spleen volumes has clinical implications. Although computed tomography (CT) volumetry is considered to be the most reliable noninvasive method for liver and spleen volume measurement, it has limited application in clinical practice due to its time-consuming segmentation process. We aimed to develop and validate a deep learning algorithm (DLA) for fully automated liver and spleen segmentation using portal venous phase CT images in various liver conditions.

Materials and Methods

A DLA for liver and spleen segmentation was trained using a development dataset of portal venous CT images from 813 patients. Performance of the DLA was evaluated in two separate test datasets: dataset-1 which included 150 CT examinations in patients with various liver conditions (i.e., healthy liver, fatty liver, chronic liver disease, cirrhosis, and post-hepatectomy) and dataset-2 which included 50 pairs of CT examinations performed at ours and other institutions. The performance of the DLA was evaluated using the dice similarity score (DSS) for segmentation and Bland-Altman 95% limits of agreement (LOA) for measurement of the volumetric indices, which was compared with that of ground truth manual segmentation.

Results

In test dataset-1, the DLA achieved a mean DSS of 0.973 and 0.974 for liver and spleen segmentation, respectively, with no significant difference in DSS across different liver conditions (p = 0.60 and 0.26 for the liver and spleen, respectively). For the measurement of volumetric indices, the Bland-Altman 95% LOA was −0.17 ± 3.07% for liver volume and −0.56 ± 3.78% for spleen volume. In test dataset-2, DLA performance using CT images obtained at outside institutions and our institution was comparable for liver (DSS, 0.982 vs. 0.983; p = 0.28) and spleen (DSS, 0.969 vs. 0.968; p = 0.41) segmentation.

Conclusion

The DLA enabled highly accurate segmentation and volume measurement of the liver and spleen using portal venous phase CT images of patients with various liver conditions.

Assessment of Radiation Dose Delivered and Volume Measurement By Low- and High-Dose Diagnostic Computed Tomography: Anthropomorphic Liver Phantom Study

AIM

Liver volume measurement is a mandatory test before measure liver surgeries and transplantation. We aimed a study on the difference in volume measurement and radiation dose to an anthropomorphic liver phantom using high-dose and low-dose diagnostic computed tomography (CT).

MATERIALS AND METHODS

Several measurements of the manual total volume measurement done on an anthropomorphic liver phantom mounted with thermoluminescent dosimeter. We exposed the phantom with diagnostic CT, low-dose CT, and a low-dose CT with copper filter.

RESULTS

Phantom underwent ten scanning for each exposure. There was no significant difference in the total volume measurement in comparison to the phantom volume. The volume of phantom measured by low-dose CT, low-dose CT with copper phantom, and high-dose CT were 1869 ± 18 cm3, 1852 ± 24 cm3, and 1908 ± 12 cm3, (P = 0.3), respectively. However, the radiation dose delivered was significantly different (1.54 mGy, 0.77 mGy, and 5.84 mGy [P = 0.001], respectively).

CONCLUSION

Total liver volume measurement provides essential clinical information in several clinical conditions. We recommended that the volume measured by a low-dose CT has an excellent correlation with the diagnostic quality CT and should be a routine in the routine clinical practice. CT volumetry achieves the same result while using very less radiation exposure. It may also be used with functional imaging to give complete information.

Effective dose for multiple and repeated radiation examinations in donors and recipients of adult-to-adult living donor liver transplants at a single center

PURPOSE

To evaluate the effective doses received by donors and recipients, identify effective dose contributions, and make risk assessments.

MATERIALS AND METHODS

It was a retrospective study. 100 Donors and 100 recipients were enrolled with an operative day from March 2016 to August 2017. The dose was analyzed for all radiation-related examinations over a period of 2 years, 1 year before and 1 year after the LDLT procedure. The effective doses of plain X-rays, CT, fluoroscopy, and nuclear medicine per patient were simulated by a Monte Carlo software, evaluated by the dose-length product conversion factors, evaluated by the dose-area product conversion factors, and evaluated by the activity conversion factors, respectively. The risks of radiation-induced cancer were assessed on the basis of the ICRP risk model.

RESULTS

The median effective doses were 71 (range: 30-186) mSv for donors and 147 (32-423) mSv for recipients. The radiation examinations were mainly performed in the last three months of preoperative period to first month of postoperative period for recipients and donors. The HCC recipients received a higher effective dose, 195 (64-423) mSv, than those with other indications. The median radiation-induced cancer risk was 0.38 % in male and 0.48 % in female donors and was 0.50 % in male and 0.58 % in female recipients.

CONCLUSION

Donors and recipients received a large effective dose, mainly from the CT scans. To reduce effective doses should be included in future challenges in some living donor liver transplants centers that often use CT examinations.

Assessment of liver function reserve by photoacoustic tomography: a feasibility study

Assessment of liver function reserve (LFR) is essential to determine liver resection scope and predict prognosis for patients with liver disease. Indocyanine green (ICG) concentration change is a classic marker to reflect liver function reserve as ICG is selectively taken up and eliminated by liver. Here we proposed a noninvasive approach for LFR assessment based on a real-time photoacoustic tomography (PAT) system. This feasibility study was to detect ICG concentration change by PAT in phantom and in vivo using both normal and partial hepatectomy (PH) rabbits. A linear relationship between photoacoustic signal intensity of ICG and ICG concentration was found in vitro. In vivo ICG concentration change over time after ICG injection was observed by PAT in normal rabbits, which was consistent with the findings measured by invasive spectrophotometry. Finally, clear difference in ICG clearance between the control and PH models was identified by PAT. Taken together, our study indicated the clinical potential of PAT to in vivo evaluate LFR noninvasively.

CT-Based Hepatic Residual Volume and Predictors of Outcomes of Patients with Hepatocellular Carcinoma Unsuitable for Surgical Therapy Undergoing Transarterial Chemoembolization

RATIONALE AND OBJECTIVES

To assess the association between baseline CT-based volumetric parameters and biochemical hepatic evaluations, such as, Child-Pugh, MELD score, and modified MELD-Na score, on the prediction of outcomes of patients with HCC undergoing transarterial chemoembolization (TACE).

MATERIALS AND METHODS

A retrospective of a prospectively maintained database, single arm, and single center study was performed including 41 patients with diagnosis of hepatocellular carcinoma treated with TACE. Study endpoints included liver dysfunction (new events of ascites, encephalopathy, and/or death) and overall survival rate. Multi-phase CT-based volumetric analysis was performed to calculate total liver volume and tumor volume using portal and late arterial phases, respectively. Residual volume was calculated subtracting the tumor volume minus the total liver volume. Child-Pugh, MELD score, and MELD-Na score were measured during the baseline evaluation.

RESULTS

At a median follow-up time of 8 months (IQR, 5-14), 16 patients (39%) were diagnosed with hepatic dysfunction. In patients with hepatic dysfunction, the median residual hepatic volume was 1002.1 cc (IQR, 633-1077.1 cc) compared to patients with normal liver function post-TACE with a median residual volume of 1233 cc (IQR, 1018.7-1437.6 cc) (p = 0.02). Survival analysis demonstrated an overall survival rate of 95%, 90%, 85% at 30 days, 12 months, and 24 months, respectively. The overall survival rate in patients with Child-Pugh A was 100%, 97%, and 97% at 6, 12, and 24 months, respectively; compared to patients with Child Pugh B with an overall survival of rate of 86%, 78%, and 78% at 6, 12, and 24 months, respectively (p = 0.07). Median baseline MELD-Na score was higher in patients that died during the study period compared to patients that survived (6.7 [IQR, 5-14.2] versus 4.1 [IQR, 2.14-6.85]) (p = 0.09).

CONCLUSION

Low baseline CT-based residual volume is associated with the occurrence of hepatic dysfunction at a median time of 8 months. Baseline Child-Pugh A patients were found to have higher survival rate than Child-Pugh B. Interestingly, higher baseline MELD-Na score was associated with mortality.

Reproducibility and reliability of computed tomography volumetry in estimation of the right-lobe graft weight in adult-to-adult living donor liver transplantation: Cantlie's line vs portal vein territorialization

BACKGROUND/PURPOSE

In living-donor liver transplantation (LDLT), liver volume assessment is a mandatory step in determining donor appropriateness. This study aimed to compare reliability and reproducibility between two major methods to define virtual hepatectomy plane, based on Cantlie's line (CTV-Cantlie) and portal vein territorialization (CTV-PVT) for right-lobe graft weight estimation in LDLT.

METHODS

A total of 188 donors who underwent preoperative CT scans were included. The liver was divided into right and left lobes using CTV-Cantlie and CTV-PTV measurements by two readers. Intraclass correlation coefficient (ICC) was used to determine interreader variability of hepatic weight measured using each CTV method. Intraoperative graft weight (IOW) was used as reference standard of right-lobe graft weight. Pearson correlation test was performed to determine correlation coefficients between presumed graft weight by each CTV method and IOW.

RESULTS

Intraclass correlation coefficients for total liver weight were roughly equivalent between the two CTV methods (CTV-Cantlie: 0.965 [95% CI, 0.954-0.974], CTV-PVT: 0.977 [0.970-0.983]). However, ICCs of right-and left-lobe weights between two readers were higher with CTV-PVT (0.997 and 0.850) than with CTV-Cantlie (0.829 and 0.668). The IOW was 716.0 ± 162.0 g. Correlation coefficients between presumed graft weight by CTV-Cantlie or CTV-PVT and IOW were 0.722 and 0.807, respectively (both P < .001).

CONCLUSIONS

For estimation of the right-lobe graft weight in LDLT, CTV-PVT may provide higher reliability and reproducibility than CTV-Cantlie.