Does preoperative analysis of intrahepatic venous anastomoses improve the surgeon's intraoperative decision making? Pilot data from a case report

Surgical treatment of extensive hepatic alveolar echinococcosis using a three-dimensional visualization technique combined with allograft blood vessels: A case report

RATIONALE

Hepatic alveolar echinococcosis (HAE) presents a high pathogenicity and case fatality rate. The main treatment for HAE is surgical resection. Giant lesions in the liver and invasion of the pathogen into the retrohepatic inferior vena cava are usually associated with a poor prognosis when radical resection cannot be performed.

PATIENT CONCERNS

A 56-year-old man who underwent hydatidectomy 7 years prior noted a recurrence of HAE. He was subsidized and admitted to our hospital for the purpose of surgical treatment.

DIAGNOSIS

By computed tomography, angiography and three-dimensional (3D) computed tomography reconstruction images, multiple, giant HAE with 75% stenosis was confirmed.

INTERVENTIONS

With the 3D visualization technique, we designed the surgical plan and performed radical resection of the lesions, including the invaded inferior vena cava, and maximized retention of normal liver tissue. The abdominal aorta of an organ donor was used for vascular allograft reconstruction.

OUTCOMES

The patient recovered gradually after the operation. He was followed up for 3 months, and the reconstructed vein patency was good.

LESSONS

The 3D visualization technique combined with a blood vessel allograft allowed us to expand indications for radical resection of extensive HAE.

Regular three-dimensional presentations improve in the identification of surgical liver anatomy - a randomized study

BACKGROUND

Three-dimensional (3D) presentations enhance the understanding of complex anatomical structures. However, it has been shown that two dimensional (2D) "key views" of anatomical structures may suffice in order to improve spatial understanding. The impact of real 3D images (3Dr) visible only with 3D glasses has not been examined yet. Contrary to 3Dr, regular 3D images apply techniques such as shadows and different grades of transparency to create the impression of 3D.This randomized study aimed to define the impact of both the addition of key views to CT images (2D+) and the use of 3Dr on the identification of liver anatomy in comparison with regular 3D presentations (3D).

METHODS

A computer-based teaching module (TM) was used. Medical students were randomized to three groups (2D+ or 3Dr or 3D) and asked to answer 11 anatomical questions and 4 evaluative questions. Both 3D groups had animated models of the human liver available to them which could be moved in all directions.

RESULTS

156 medical students (57.7% female) participated in this randomized trial. Students exposed to 3Dr and 3D performed significantly better than those exposed to 2D+ (p < 0.01, ANOVA). There were no significant differences between 3D and 3Dr and no significant gender differences (p > 0.1, t-test). Students randomized to 3D and 3Dr not only had significantly better results, but they also were significantly faster in answering the 11 anatomical questions when compared to students randomized to 2D+ (p < 0.03, ANOVA). Whether or not "key views" were used had no significant impact on the number of correct answers (p > 0.3, t-test).

CONCLUSION

This randomized trial confirms that regular 3D visualization improve the identification of liver anatomy.

Intrahepatic venous anastomoses with a focus on the middle hepatic vein anastomoses in normal human livers: anatomical study on liver corrosion casts

PURPOSE

The aim of this study is to present the anatomical data about intrahepatic venous anastomoses found in normal human livers. The focus is on the middle hepatic vein (MHV) anastomoses, because their existence or non-existence could be of crucial importance in tumour resections as well as in split or living donor liver transplantations.

MATERIALS AND METHODS

The frequency of livers with intrahepatic venous anastomoses was determined on 164 corrosion casts and the diameter of each anastomosis was measured. Additionally, the type of connection and the position within the liver (liver segment) was determined for each MHV anastomosis.

RESULTS

Intrahepatic venous anastomoses were found in 46 % (75/164), whereas MHV anastomoses were found in 28 % (44/164) of liver casts. Most commonly (39/44), MHV had anastomotic connections with the right hepatic vein (RHV), and also with the inferior RHV, the left hepatic vein and the short subhepatic vein. In more than three quarters of liver casts, MHV-RHV anastomoses were found in liver segment 8; in 45 % of cases, there was more than one anastomosis in this liver segment. The diameter of MHV-RHV anastomoses found in segment 8 was ≥1 mm in 90.6 % of cases.

CONCLUSION

As MHV anastomoses were present in more than a quarter of all examined liver casts, we believe that detailed anatomical data presented in this article, together with up to date radiologic technics which enable even 3D reconstruction of venous anastomoses in the liver, could contribute to the clinician's decisions when planning surgical procedures.

Teaching on three-dimensional presentation does not improve the understanding of according CT images: a randomized controlled study

BACKGROUND

Randomized studies have already described the advantages of three dimensional (3D) presentations in understanding complex spatial interactions. However, the clinical setting is mainly characterized by presentations of two dimensional (2D) images.

PURPOSE

This study evaluates whether training on 3D presentation enhances the understanding of 2D images.

METHODS

A teaching module was used consisting of one learning part and two examination parts (EP). Students were randomized to training with either 2D or 3D.

RESULTS

This study of 73 students showed that training on 3D presentations did not improve the ability to interpret 2D images. Further, the results revealed no significant differences between the results of Week 1 (2D: M = 6.5, SD = 1.8; 3D: M = 6.6, SD = 1.4; p > .95) and Week 2 (2D: M = 6.1, SD = 1.9; 3D: M = 6.0, SD = 1.4; p > .7). There were no significant gender differences. However, students randomized to 2D who completed only the first EP performed significantly worse if compared to students who completed both EP ( p = .04).

CONCLUSIONS

This randomized controlled study shows that correct interpretation of 2D imaging does not differ in students trained with either 3D or 2D.

Three-dimensional visualisation improves understanding of surgical liver anatomy

OBJECTIVES

Three-dimensional (3-D) representation is thought to improve understanding of complex spatial interactions and is being used more frequently in diagnostic and therapeutic procedures. It has been suggested that males benefit more than females from 3-D presentations. There have been few randomised trials to confirm these issues. We carried out a randomised trial, based on the identification of complex surgical liver anatomy, to evaluate whether 3-D presentation has a beneficial impact and if gender differences were evident.

METHODS

A computer-based teaching module (TM) was developed to test whether two-dimensional (2-D) computed tomography (CT) images or 3-D presentations result in better understanding of liver anatomy. Following a PowerPoint lecture, students were randomly selected to participate in computer-based testing which used either 2-D images presented as consecutive transversal slices, or one of two 3-D variations. In one of these the vessel tree of portal and hepatic veins was shown in one colour (3-D) and in the other the two vessel systems were coloured differently (3-Dc). Participants were asked to answer 11 medical questions concerning surgical anatomy and four questions on their subjective assessment of the TM.

RESULTS

Of the 160 Year 4 and 5 medical students (56.8% female) who participated in this prospective randomised trial, students exposed to 3-D presentation performed significantly better than those exposed to 2-D images (p < 0.001). Comparison of the number of correct answers revealed no significant differences between the 3-D and 3-Dc modalities p > 0.1). Male students gave significantly more correct answers in the 3-D and 3-Dc modalities than female students (p < 0.03). The gender difference observed in both 3-D modalities was not evident in the 2-D group (p = 0.21).

CONCLUSIONS

This study showed that 3-D imaging significantly improved the identification of complex surgical liver anatomy. Male students benefited significantly more than female students from 3-D presentations. Use of colour in 3-D presentation did not improve student performance.

How many CT detector rows are necessary to perform adequate three dimensional visualization?

INTRODUCTION

The technical development of computer tomography (CT) imaging has experienced great progress. As consequence, CT data to be used for 3D visualization is not only based on 4 row CTs and 16 row CTs but also on 64 row CTs, respectively. The main goal of this study was to examine whether the increased amount of CT detector rows is correlated with improved quality of the 3D images.

MATERIAL AND METHODS

All CTs were acquired during routinely performed preoperative evaluation. Overall, there were 12 data sets based on 4 detector row CT, 12 data sets based on 16 detector row CT, and 10 data sets based on 64 detector row CT. Imaging data sets were transferred to the DKFZ Heidelberg using the CHILI teleradiology system. For the analysis all CT scans were examined in a blinded fashion, i.e. both the name of the patient as well as the name of the CT brand were erased. For analysis, the time for segmentation of liver, both portal and hepatic veins as well as the branching depth of portal veins and hepatic veins was recorded automatically. In addition, all results were validated in a blinded fashion based on given quality index.

RESULTS

Segmentation of the liver was performed in significantly shorter time (p<0.01, Kruskal-Wallis test) in the 16 row CT (median 479 s) compared to 4 row CT (median 611 s), and 64 row CT (median 670 s), respectively. The branching depth of the portal vein did not differ significantly among the 3 different data sets (p=0.37, Kruskal-Wallis test). However, the branching depth of the hepatic veins was significantly better (p=0.028, Kruskal-Wallis test) in the 4 row CT and 16 row CT compared to 64 row CT. The grading of the quality index was not statistically different for portal veins and hepatic veins (p=0.80, Kruskal-Wallis test). Even though the total quality index was better for the vessel tree based on 64 row CT data sets (mean scale 2.6) compared to 4 CT row data (mean scale 3.25) and 16 row CT data (mean scale 3.0), these differences did not reach statistical difference (p=0.53, Kruskal-Wallis test).

CONCLUSION

Even though 3D visualization is useful in operation planning, the quality of the 3D images appears to be not dependent of the number of CT detector rows.