Is computed tomography volumetric assessment of the liver reliable in patients with cirrhosis?

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.

Predicting the available space for liver transplantation in cirrhotic patients: a computed tomography-based volumetric study

BACKGROUND

Anthropometric parameters (weight, height) are usually used for quick matching between two individuals (donor and recipient) in liver transplantation (LT). This study aimed to evaluate clinical factors influencing the overall available space for implanting a liver graft in cirrhotic patients.

METHODS

In a cohort of 275 cirrhotic patients undergoing LT, we calculated the liver volume (LV), cavity volume (CV), which is considered the additional space between the liver and the right hypocondrium, and the overall volume (OV = LV + CV) using a computed tomography (CT)-based volumetric system. We then chose the formula based on anthropometric parameters that showed the best predictive value for LV. This formula was used to predict the OV in the same population. Factors influencing OV variations were identified by multivariable logistic analysis.

RESULTS

The Hashimoto formula (961.3 × BSA_D-404.8) yielded the lowest median absolute percentage error (21.7%) in predicting the LV. The median LV was 1531 ml. One-hundred eighty-five patients (67.2%) had a median CV of 1156 ml (range: 70-7006), and the median OV was 2240 ml (range: 592-8537). Forty-nine patients (17%) had an OV lower than that predicted by the Hashimoto formula. Independent factors influencing the OV included the number of portosystemic shunts, right anteroposterior abdominal diameter, model for end-stage liver disease (MELD) score > 25, high albumin value, and BMI > 30.

CONCLUSIONS

Additional anthropometric characteristics (right anteroposterior diameter, body mass index) clinical (number of portosystemic shunts), and biological (MELD, albumin) factors might influence the overall volume available for liver graft implantation. Knowledge of these factors might be helpful during the donor-recipient matching.

ALPPS for hepatocarcinoma under cirrhosis: a feasible alternative to portal vein embolization

Hepatocellular carcinoma (HCC) is one of the most common and malignant tumors. Preoperative portal vein embolization (PVE) is currently the most accepted treatment before major hepatic resection for HCC in patients with liver fibrosis or cirrhosis and associated insufficient future liver remnant (FLR). In the last decade, associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) technique has been described to obtain an increase of volume regarding PVE and a decrease of drop out. The initial excessive morbidity and mortality of this technique have decreased drastically due to a better selection of patients, the learning curve and the use of less aggressive variations of the original technique in the first stage. For both techniques a complete preoperative assessment of the FLR is the most important issue and only patients with and adequate FLR should be resected. ALPPS could be a feasible technique in very selected patients with HCC and cirrhosis. As long as it is performed in an experienced center could be used as a first choice technique versus PVE or could be used as a rescue technique in case of PVE failure.

Does providing routine liver volume assessment add value when performing CT surveillance in cirrhotic patients?

BACKGROUND

The measurement of liver volume (LV) is considered to be an effective prognosticator for postoperative liver failure in patients undergoing hepatectomy. It is unclear whether LV can be used to predict mortality in cirrhotic patients.

METHODS

We enrolled 584 consecutive cirrhotic patients who underwent computerized topography (CT) of the abdomen for hepatocellular carcinoma surveillance and 50 age, gender, race, and BMI-matched controls without liver disease. Total LV (TLV), functional LV (FLV), and segmental liver volume (in cm³) were measured from CT imaging. Cirrhotic subjects were followed until death, liver transplantation, or study closure date of July 31, 2016. The survival data were assessed with log-rank statistics and independent predictors of survival were performed using Cox hazards model.

RESULTS

Cirrhotic subjects had significantly lower TLV, FLV, and segmental (all except for segments 1, 6, 7) volume when compared to controls. Subjects presenting with hepatic encephalopathy had significantly lower TLV and FLV than those without HE (p = 0.002). During the median follow-up of 1145 days, 112 (19%) subjects were transplanted and 131 (23%) died. TLV and FLV for those who survived were significantly higher than those who were transplanted or dead (TLV:1740 vs. 1529 vs. 1486, FLV 1691 vs. 1487 vs. 1444, p < 0.0001). In the Cox regression model, age, MELD score, TLV, or FLV were independent predictors of mortality.

CONCLUSION

Baseline liver volume is an independent predictor of mortality in subjects with cirrhosis. Therefore, it may be useful to provide these data while performing routine surveillance CT scan as an important added value. Further studies are needed to validate these findings and to better understand their clinical utility.

Should We Have Blind Faith in Liver Volumetry?

Introduction: Liver volumetry is a routine procedure performed before major hepatectomy or living donor liver transplantation (LDLT) to anticipate the remnant liver volume and prevent liver failure. However, many parameters may impact its accuracy and no large-scale studies have evaluated inter-rater variabilities. We aimed to determine the reliability of volumetric assessments for whole organs in deceased-donor liver transplantations (DDLT) and partial organs in LDLT settings. Patients & Methods: Eight operators (four surgeons + four radiologists) analysed 30 preoperative CT scans (15 whole cirrhotic livers in the DDLT group + 15 partial healthy grafts in the LDLT group), using five software systems. The computed volumes were compared with liver weight; liver density being considered as1. Results: Inter-rater and inter-software concordances were excellent with coefficients of correlation >0.9. However, calculations overestimated the real volumes in 25 cases by a mean of 249 ± 206 [14-771] cc in the DDLT group and 138 ± 92cc [39-375] in the LDLT group. The mean calculations were significantly higher than liver weights in the LDLT group only (p=0.04). The radiologists overestimated the surgeons’ assessment in 24 cases, the differences exceeding 6% in some cases. The type of software used significantly impacted results in the DDLTgroup. Conclusions: Despite its unanimously recognised utility, we highlight significant discrepancies between estimated and real liver volumes. The global overestimation may lead to leave of too small remnant liver, with potentially dramatic consequences. In case of border-line estimations, we recommend a repetition of the evaluation by another operator (surgeon + radiologist working in concert).

Use of Computed Tomography Volumetry to Assess Liver Weight in Patients With Cirrhosis During Evaluation Before Living-Donor Liver Transplant

OBJECTIVES

Computed tomography liver volumetry has been widely used to detect total and segmental liver volume in living-donor liver transplantation. However, use of this technique to evaluate the cirrhotic liver remains unclear. In this study, we evaluated the accuracy of freehand computed tomography volumetry to assess total liver volume by comparing weights of total hepatectomy specimens in patients with cirrhosis. For our analyses, we considered the density of a cirrhotic liver to be 1.1 kg/L.

MATERIALS AND METHODS

Liver volume was measured using a freehand computed tomography technique in 52 patients with cirrhosis from different causes and who had no solid lesions before transplant. Measurements were made with a 16-slice multidetector computed tomography scanner (Siemens Somatom Sensation 16, Erlangen, Germany). For volumetric measurements, 10-mm-thick slices with 10-mm reconstruction intervals were preferred. Total hepatectomy weights of explant livers and computed tomography volumetry data were compared.

RESULTS

We excluded 3 cirrhotic patients with Budd-Chiari syndrome due to wide variations in scatterplot results. In the 49 patients included in the final analyses, average estimated liver volume by computed tomography was 721 ± 398 mL and actual cirrhotic liver weight was 727.8 ± 415 g. No significant differences were shown between these measurements. A simple regression analysis used to analyze correlations between estimated liver volume by computed tomography and real cirrhotic liver weight showed correlation of 0.957 (P < .001). When computed tomography liver volumetry as the independent variable and cirrhotic liver weight as dependent variable were considered, regression analyses showed R2 = 0.915.

CONCLUSIONS

Freehand computed tomography liver volumetry can be confidently used to evaluate liver volume in cirrhotic liver patients similar to use of this technique to estimate actual weights in normal livers. This technique can also be valuable during pretransplant and liver resection evaluations to ensure a more successful outcome.

Assessing the accuracy and reliability of ultrasonographic three-dimensional parathyroid volume measurement in a patient with secondary hyperparathyroidism: a comparison with the two-dimensional conventional method

Purpose

The purpose of this study was to investigate the accuracy and reliability of the semi-automated ultrasonographic volume measurement tool, virtual organ computer-aided analysis (VOCAL), for measuring the volume of parathyroid glands.

Methods

Volume measurements for 40 parathyroid glands were performed in patients with secondary hyperparathyroidism caused by chronic renal failure. The volume of the parathyroid glands was measured twice by experienced radiologists by two-dimensional (2D) and three-dimensional (3D) methods using conventional sonograms and the VOCAL with 30°angle increments before parathyroidectomy. The specimen volume was also measured postoperatively. Intraclass correlation coefficients (ICCs) and the absolute percentage error were used for estimating the reproducibility and accuracy of the two different methods.

Results

The ICC value between two measurements of the 2D method and the 3D method was 0.956 and 0.999, respectively. The mean absolute percentage error of the 2D method and the 3D VOCAL technique was 29.56% and 5.78%, respectively. For accuracy and reliability, the plots of the 3D method showed a more compact distribution than those of the 2D method on the Bland-Altman graph.

Conclusion

The rotational VOCAL method for measuring the parathyroid gland is more accurate and reliable than the conventional 2D measurement. This VOCAL method could be used as a more reliable follow-up imaging modality in a patient with hyperparathyroidism.