CT- and MRI-based volumetry of resected liver specimen: Comparison to intraoperative volume and weight measurements and calculation of conversion factors

doi:10.1016/j.ejrad.2009.09.005

European Journal of Radiology

Volume 75, Issue 1, July 2010, Pages e107-e111

https://doi.org/10.1016/j.ejrad.2009.09.005 Get rights and content

Abstract

Objective

To compare virtual volume to intraoperative volume and weight measurements of resected liver specimen and calculate appropriate conversion factors to reach better correlation.

Methods

Preoperative (CT-group, n = 30; MRI-group, n = 30) and postoperative MRI (n = 60) imaging was performed in 60 patients undergoing partial liver resection. Intraoperative volume and weight of the resected liver specimen was measured. Virtual volume measurements were performed by two readers (R1,R2) using dedicated software. Conversion factors were calculated.

Results

Mean intraoperative resection weight/volume: CT: 855 g/852 mL; MRI: 872 g/860 mL. Virtual resection volume: CT: 960 mL(R1), 982 mL(R2); MRI: 1112 mL(R1), 1115 mL(R2). Strong positive correlation for both readers between intraoperative and virtual measurements, mean of both readers: CT: R = 0.88(volume), R = 0.89(weight); MRI: R = 0.95(volume), R = 0.92(weight). Conversion factors: 0.85(CT), 0.78(MRI).

Conclusion

CT- or MRI-based volumetry of resected liver specimen is accurate and recommended for preoperative planning. A conversion of the result is necessary to improve intraoperative and virtual measurement correlation. We found 0.85 for CT- and 0.78 for MRI-based volumetry the most appropriate conversion factors.

Introduction

Magnetic resonance imaging (MRI) and multidetector computed tomography (MDCT) provide an exact characterization and localization of focal liver lesions and are therefore essential contributors to preoperative planning procedures in liver surgery today. In partial liver resections, which are performed with an increasing frequency [1], the surgeons aim for a total resection of focal liver lesions, but they need to avoid an extensive loss of healthy liver parenchyma, since this can lead to postoperative hepatic failure. The minimal, patient-adapted liver volume to avert this risk has been evaluated by various studies [2], [3], [4]. In order to perform partial liver resections safely, the determination of the entire preoperative liver volume and the soon-to-be remaining postoperative liver volume is important. This task is achieved by virtual, MDCT- or MRI-based volumetry, which is a well known and accepted procedure today [4], [5]. The most common technique is the volumetric measurement after semi-automated segmentation. Various studies have demonstrated a close correlation between intraoperative liver volume or weight measurements and virtually measured liver volumes [6], [7], [8], [9], [10], [11]. However, to obtain a more accurate result, some studies proposed the implementation of conversion factors, but so far these studies had been concentrating on the field of liver transplantation and CT-based volumetry [6], [7], [8].

The purpose of our study was to compare intraoperative volume and weight measurements of resected liver specimen to virtual volume measurements based on MDCT and MRI data to calculate appropriate conversion factors.

Section snippets

Materials and methods

Between June 2006 and March 2007, a total of 60 patients (mean age 57 years, range 28–90 years, 34 males) with known focal liver lesions underwent partial liver resection at our hospital (Table 1). Preoperative MDCT (CT-group, n = 30) or MRI (MRI-group, n = 30) was performed for surgical planning. Postoperative MRI was performed within the routine follow up 8 days after surgery in all patients (n = 60). The weight and volume of all resected liver specimen was measured by the surgeons in the operating

Intraoperative measurements

The mean resection volume for all patients was 856 mL (range 120–2750 mL; SD ± 598 mL); the mean weight was 863 g (range 118–2858 g; SD ± 539 g).

The mean resection volume in the CT-group was 852 mL (range 120–2750 mL; SD ± 544 mL); the mean weight was 855 g (range 118–2858 g, SD ± 574 g).

The mean resection volume in the MRI-group was 860 mL (range 200–2250 mL, SD ± 473 mL); the mean weight was 872 g (range 126–2294 g; SD ± 514 g).

Virtual measurements

Bland–Altman analysis revealed minimal mean differences between the measurements of both

Discussion

The liver has the ability to regenerate quickly after surgery [1]. Based on an increased knowledge of this phenomenon, and due to constantly improving perioperative management, safer strategies in liver surgery have been developed [13], [14], [15]. Additionally, modern imaging techniques like MDCT [16] and MRI have improved surgical management. The identification and quantification of intra- and extrahepatic tumor manifestation plays a central role in preoperative planning procedures, e.g.

Conclusion

CT- and MRI-based volumetry of resected liver specimen is accurate and reproducible and therefore recommended for preoperative planning in liver surgery. However a conversion of the result is necessary to improve intraoperative and virtual measurement correlation. We found a slight difference between CT- and MRI-based volumetry and therefore propose conversion factors of 0.85 for CT- and 0.78 for MRI-based volumetry.

Financial disclosure

All of the authors have nothing to disclose.

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CT- and MRI-based volumetry of resected liver specimen: Comparison to intraoperative volume and weight measurements and calculation of conversion factors

Abstract

Objective

Methods

Results

Conclusion

Introduction

Section snippets

Materials and methods

Intraoperative measurements

Virtual measurements

Discussion

Conclusion

Financial disclosure

Am J Transplant

J Hepatol

Transplant Proc

Strategies for safer liver surgery and partial liver transplantation

N Engl J Med

The value of residual liver volume as a predictor of hepatic dysfunction and infection after major liver resection

Gut

Postoperative liver dysfunction and future remnant liver: where is the limit? Results of a prospective study

World J Surg

Prediction of the safe limits of hepatectomy by combined volumetric and functional measurements in patients with impaired hepatic function

Cancer Treat Res

Hepatic metastases from colorectal cancer: influence of hepatic volumetric analysis on surgical decision making

Radiology

Accuracy of the CT-estimated weight of the right hepatic lobe prior to living related liver donation (LRLD) for predicting the intraoperatively measured weight of the graft

Rofo

Living donor right liver lobes: preoperative CT volumetric measurement for calculation of intraoperative weight and volume

Radiology