Biomedical subjects

Heinz O Peitgen

Publications and source records attributed to Heinz O Peitgen.

4 recordsLinked to original sources

PubMed2005

Three-dimensional visualization and virtual simulation of resections in pediatric solid tumors.

PURPOSE: Three-dimensional visualization of solid tumors is possible because of high-resolution computed tomography and magnetic resonance imaging scans. However, additional preoperative information is often desirable in complex malignancies. For the first time, the authors present a model of preoperative 3-dimensional visualization and virtual resections in pediatric solid tumors. METHODS: Image analysis of various pediatric tumors was performed using the research software HepaVision2 (MeVis, Bremen). Organs, tumors, and the vascular system were extracted from multislice computed tomography scans. After hierarchical analysis of the vascular system, territories supplied or drained by the major vascular branches were calculated. Results were explored and virtual resections of organs were carried out using the research software InterventionPlanner (MeVis, Bremen). Data were correlated to intraoperative findings. RESULTS: Four hepatic malignancies, 4 renal tumors, and 3 other neoplasms were analyzed. The technique of 3-dimensional visualization was feasible for all investigated children (mean age 5 years and 9 months). Spatial relations between physiological and pathological structures were identified, and anatomical structures (vessels, tumor tissue, and organ parenchyma) were determined using colorimetric encoding. Virtual simulations of tumor resection were used successfully for planning of surgical procedures in the hepatic and renal tumors. CONCLUSIONS: The technique of 3-dimensional tumor visualization and virtual simulation of tumor resections provides the basis for a successful planning of complex tumor resections in children. The efficiency of these techniques should be further analyzed in series with higher numbers and differentiations of tumors.

Child↗

PubMed2003

Extended left hepatectomy--modified operation planning based on three-dimensional visualization of liver anatomy.

BACKGROUND: Based on the patient history of a 62-year-old man with a centrally located hepatocellular carcinoma we describe the potential influence of three-dimensional computed tomography (3D CT) on operation planning in extended left hepatectomy. METHOD AND RESULTS: By 3D reconstruction of the liver, not only variations of the intrahepatic vascular structure but also the number and extent of portal venous segments, as well as their relation to hepatic veins, can be visualized. Thus, areas at risk for either devascularization or venous congestion may be identified prior to liver resection. This is particularly important in extended hepatectomies with a small liver remnant, where already minor complications may have fatal consequences. CONCLUSION: In these resections, operation planning may be improved substantially by pre-operative 3D reconstruction.

Carcinoma, Hepatocellular↗

PubMedDate not supplied

Anatomical and physiological comparison of liver volumes among three frequent types of parenchyma transection in live donor liver transplantation.

BACKGROUND/AIMS: Adequate venous outflow is a prerequisite for successful live donor liver transplantation. Several techniques of liver transection have been established in both transplant and non-transplant hepatic surgery. The purpose of our study was to define and compare anatomical and physiological characteristics of venous drainage in the three most common types of liver transection techniques (Malagó, Cantlie, Pringle) encountered in live donor liver transplantation METHODOLOGY: Volumes of both graft and remnant livers as well as individual hepatic vein territories were calculated by means of virtual 3-dimensional reconstructions of computed tomography images obtained from 55 potential live liver donors using the software HepaVision (MeVis, Germany). Belonging to the middle hepatic vein (MHV) was assigned according to the largest territorial volume on either right or left hemilivers. Livers from all potential donors were subject to virtual splitting (n=55). Findings were subsequently confirmed intraoperatively in those who underwent donor resection (n=27). RESULTS: There were no statistically significant differences in hemiliver-volumes among the three types of liver partition. There was a predominance of MHV belonging to the right hemiliver: Malagó n=45 (82%) vs. Cantlie n=44 (80%) vs. Pringle n=44 (80%). Dominant right MHV hemiterritory showed a mean volume of 284-296 mL, accounting for 59-61% of total MHV volume. There were no significant differences among the three types of liver partition evaluated. CONCLUSIONS: Our results demonstrate the reliability of virtual 3-dimensional reconstructions based on standard anatomical landmarks for both surgical planning and graft volume calculations. We believe our technique will help prevent small-for-size grafting and liver insufficiency resulting from inaccurate volumetric calculations. Our findings also support the observation that improved venous outflow might be achieved by including the MHV with the right liver graft without disadvantaging the left liver remnant. It is our hope that all these findings will translate into enhanced donor and recipient safety.

Adult↗

PubMedDate not supplied

Parenchyma transection in adult live donor liver transplantation: the virtual dilemma of "where to cut". Experience based on virtual 3-dimensional computed tomography imaging reconstructions.

BACKGROUND/AIMS: Adequate venous drainage is essential to prevent parenchyma congestion in graft and remnant livers after adult live donor liver transplantation (ALDLT). The areas particularly prone to congestion are the right and left medial sectors. The purpose of our study was to evaluate two types of liver transection techniques (Cantlie, Malagó) frequently encountered in ALDLT and to determine their resulting anatomical and functional liver graft volumes. METHODOLOGY: Livers from 58 potential live liver donors were subject to a virtual 3-dimensional liver partition for right graft hepatectomy. Anatomical (post-transectional) volumes of both right graft and left remnant livers in either liver partition group were initially estimated and corresponding anatomic-GVBWR for the graft hemiliver was calculated. Additionally the potential venous drainage impairment in the medial area of the graft, which was influenced by the two different transection planes, was estimated giving the baseline for the calculation of the functional-GVBWR of the graft. RESULTS: Computer analysis showed no statistically significant differences in the anatomical volumetric parameters between the two potential types of liver partition. However, virtual liver partition following the Cantlie line showed significant decrease of functional volumetric parameters for right liver graft, due to incidental detachment of the right-sided tributaries of middle hepatic vein. CONCLUSIONS: Image-based computer assistance allows for areas at risk for devascularization or venous congestion to be identified and calculated before parenchyma transection in ALDLT. According to the results of this study, minimal modifications of the transection line can provide significant increases in functional volumetric parameters by avoiding venous congestion in the marginal zone of the graft, drained by the middle hepatic vein.

Adult↗