Cardiovasc Intervent Radiol DOI 10.1007/s00270-014-0931-0
TECHNICAL NOTE
Three-Dimensional Path Planning Software-Assisted Transjugular Intrahepatic Portosystemic Shunt: A Technical Modification Jiaywei Tsauo • Xuefeng Luo • Linchao Ye Xiao Li
•
Received: 22 March 2014 / Accepted: 3 May 2014 Ó Springer Science+Business Media New York and the Cardiovascular and Interventional Radiological Society of Europe (CIRSE) 2014
Abstract Purpose This study was designed to report our results with a modified technique of three-dimensional (3D) path planning software assisted transjugular intrahepatic portosystemic shunt (TIPS). Methods 3D path planning software was recently developed to facilitate TIPS creation by using two carbon dioxide portograms acquired at least 20° apart to generate a 3D path for overlay needle guidance. However, one shortcoming is that puncturing along the overlay would be technically impossible if the angle of the liver access set and the angle of the 3D path are not the same. To solve this problem, a prototype 3D path planning software was fitted with a utility to calculate the angle of the 3D path. Using this, we modified the angle of the liver access set accordingly during the procedure in ten patients. Results Failure for technical reasons occurred in three patients (unsuccessful wedged hepatic venography in two cases, software technical failure in one case). The procedure was successful in the remaining seven patients, and only one needle pass was required to obtain portal vein access in each case. The course of puncture was J. Tsauo X. Luo X. Li (&) Institute of Interventional Radiology, West China Hospital of Sichuan University, 37 Guoxue Lane, Chengdu 610041, Sichuan, China e-mail: [email protected] J. Tsauo e-mail: [email protected] X. Luo e-mail: [email protected] L. Ye Healthcare Sector, Siemens Ltd, Shanghai 201318, China e-mail: [email protected]
comparable to the 3D path in all patients. No procedurerelated complication occurred following the procedures. Conclusions Adjusting the angle of the liver access set to match the angle of the 3D path determined by the software appears to be a favorable modification to the technique of 3D path planning software assisted TIPS. Keywords Transjugular intrahepatic portosystemic shunt Three-dimensional imaging Punctures Computer-assisted
Introduction Transjugular intrahepatic portosystemic shunt (TIPS) is an established interventional procedure used for the management of portal hypertension [1]. To achieve the goal of creating an artificial shunt between the hepatic vein and the portal vein percutaneously, a maneuver more or less commonly referred to as ‘‘portal vein puncture’’ is employed to gain portal vein access. Conventional portal vein puncture is categorically a ‘‘blind puncture’’ as the portal vein cannot be visualized at routine fluoroscopy, and therefore, it is generally considered the most technically difficult step in TIPS creation [2]. Three-dimensional (3D) path planning software was recently introduced by Adamus et al. [3]. Its goal was to facilitate portal vein puncture by using two carbon dioxide (CO2) portograms acquired at least 20° apart to generate a 3D path for overlay needle guidance. The main advantages of this technique includes ease of use, reliable needle guidance, and minimal disruption to normal procedural workflow. However, one shortcoming of this technique is that puncturing along the overlay would be technically impossible to achieve if the angle of the liver
123
J. Tsauo et al.: Modified 3D Software Assisted TIPS
access set and the angle of the 3D path are not precisely the same. This is problematic, because the angle of the 3D path is unknown; thus, it is difficult to accurately adjust the angle of the liver access set. To solve this problem, a new utility used to calculate the angle of the 3D path has been fitted in a prototype 3D path planning software. Using this, we were able to adjust the angle of the liver access set accordingly during the procedure. We report our results with this technique in ten patients.
Materials and Methods Approval from our institutional review board was obtained for this report, and written informed consent was acquired from all patients. Between August 2012 and April 2013, ten patients underwent attempted 3D path planning software-assisted TIPS at our institution, including seven men and three women with a mean age of 48.8 years (range, 35–67 years). Eight patients had hepatitis B virus-induced hepatic cirrhosis and two had alcoholic cirrhosis. Seven patients underwent TIPS for the prevention of variceal rebleeding and three for intractable ascites. Three patients were Child-Pugh class A, five were class B, and two were class C. Before the procedure, all patients had undergone contrast-enhanced, computed-tomography (CT), which revealed patent portal vein and normal anatomy. All procedures were performed by an interventional radiologist with 3 years of experience performing TIPS. The procedures were performed on a flat-panel detector C-arm angiography system (AXIOM Artis dTA; Siemens Healthcare, Forchheim, Germany). With the patients under conscious sedation and local anesthesia, access to the right jugular vein was obtained and the right hepatic vein was catheterized. Wedged hepatic venography in posterioranterior and 30° right anterior oblique projections were performed using an end-hole catheter and 40 mL CO2 during suspended respiration. If the catheter could not be wedged in the hepatic vein, or if the portal vein could not be clearly visualized, balloon occlusion wedged hepatic venography were performed. The CO2 portograms were transferred to a separate research workstation equipped with a prototype 3D path planning software (Siemens Healthcare). The operator plans the path of portal vein puncture by marking the starting point and end point on both portograms (i.e., right hepatic vein and right portal vein), and a corresponding 3D path was automatically produced by the software (Fig. 1). The 3D path was overlaid on live fluoroscopy using the software. This overlay adjusts in real-time to C-arm and table movements, source-to-detector distance, and field of view. Manual correction can be performed through the software if patient
123
Fig. 1 The starting point (hepatic vein) and end point (portal vein) are respectively marked (yellow dot) on two CO2 portograms acquired in posterior-anterior and 30° right anterior oblique projections by using the 3D path planning software. The intersections of the projections lines (orange line) of the marked points reveal its 3D coordinates (green dot), which is automatically connected by the software to obtain the corresponding 3D path (blue line)
Fig. 2 The angle of the liver access set is manually adjusted by the operator to match the angle of the 3D path using a digital protractor (i.e., if the angle of the 3D path determined by the software is 48° then the angle of the liver access would be modified to 132°)
movement is detected during the procedure. The angle of the 3D path was determined by the software, and a Ro¨schUchida liver access set (RUPS-100; Cook, Bloomington, IN) was manually adjusted by the operator to match this angle using a digital protractor (DA-101, Calibeur, Shenzhen, China) (Fig. 2). The modified liver access set was introduced into the hepatic vein, and the puncture needle was advanced along the overlaid 3D path (Fig. 3). After portal vein access has been confirmed by portography, portosystemic pressure gradient (PPG) and portography was measured. The portosystemic tract was dilated
J. Tsauo et al.: Modified 3D Software Assisted TIPS Fig. 3 A 41-year-old man with liver cirrhosis undergoing 3D path planning software assisted TIPS to prevent variceal rebleeding. A The puncture needle is advanced along the overlaid 3D path under fluoroscopy guidance. B Portogram showing that the portal vein access is obtained. C A 10 9 60-mm stent-graft is deployed across the intrahepatic portosystemic tract. D Final venogram obtained after variceal embolization showing successful embolization and antegrade flow through the shunt
with an 8 mm balloon (PowerFlex P3; Cordis Europa N.V., LJ Roden, The Netherlands) and a 10 mm stent-graft (Fluency Plus; Bard, Tempe, Arizona, USA) was placed. The PPG was measured again, and if the gradient was higher than 13 mm Hg, the shunt was dilated with a 10 mm balloon (PowerFlex P3; Cordis Europa N.V.). The final portography was performed, and patients with esophagogastric varices underwent variceal embolization.
Results CO2 portograms were obtained by wedged hepatic venography performed using an end-hole catheter in six patients. Balloon occlusion wedged hepatic venography was required in four patients, but opacification of the portal vein was only achieved in two patients, and thus, the remaining two patients underwent indirect portography.
The eight patients with CO2 portograms underwent 3D path planning software assisted TIPS. However, software technical failure occurred in one patient; thus, this patient and the two who failed wedged hepatic venography underwent conventional TIPS using a liver access set modified based on portograms alone. The procedure was technically successful in all three patients without any procedure-related complications. Two needle passes were required to gain portal vein access in two patients, and three needle passes were required in one patient. The subsequent results exclude these three patients that did not underwent 3D path planning software assisted TIPS. The liver access set was successfully modified to match the angle determined by the software in all seven patients (mean 3D path angle, 30°; range, 21–48°). Using this, we obtained portal vein access in all patients, and only one needle pass was required in each case. The course of puncture was comparable to the 3D path in all patients, of
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J. Tsauo et al.: Modified 3D Software Assisted TIPS
which portal blood was directly aspirated in four patients and portography confirmed perfect portal vein puncture (the puncture needle did not penetrate the back wall of the portal vein) in these cases. No notable patient movement was detected during portal puncture and thus, no manual correction was required. Only one stent-graft was placed in each patient, and three patients required an additional 10 mm balloon for dilation. The average procedure time (defined as the interval from jugular vein puncture to final portography) was 43 min (range 29–51), and the average fluoroscopy time during this period was 11 min (range 7–16). No procedure-related complications occurred following the procedures.
Discussion Although most TIPS procedures are very straightforward and could be completed within 1 to 2 h, in ‘‘difficult’’ cases (such as distorted anatomy, portal vein thrombosis, or children) and for physicians with less experience, technical failure due to unsuccessful portal vein puncture still constitute a problem [4]. Furthermore, the procedure has a small risk of severe complications associated with portal vein puncture, such as hemoperitoneum, hemobilia, and hepatic artery injury [5]. Thus, from a technical standpoint, researchers have continually focused on improving the accuracy of portal vein puncture [6–12]. In contrast to previously described techniques, 3D path planning software does not involve the placement of the apparatus into the portal vein or hepatic artery, and there is no requirement for additional imaging modalities. Thus, this technique will not increase the invasiveness of TIPS procedure and may be particularly helpful for operators with less experience in medical imaging. However, one shortcoming of this technique is that puncturing along the overlay would be technically impossible to achieve if the angle of the liver access set and the angle of the 3D path are not the same. Thus, we evaluated whether adjusting the angle of the liver access set to match the angle of the 3D path determined by the 3D path planning software was a favorable modification to the technique of 3D path planning software assisted TIPS. Our results showed that there was a rather high rate of failure for technical reasons. The technique seems to efficiently allow access into the portal vein, but perfect puncture could not be achieved in every case. Our results also showed that the length of procedure time was favorable. Unsuccessful opacification of the portal vein by wedged hepatic venography can occur in 15 % of patients with cirrhosis [13]. In these patients, 3D path planning softwareassisted TIPS would be unfeasible, because it is an inherent limitation of this technique. To solve this problem,
123
improvements should perhaps be made to allow this software to support indirect portography, which is a reliable way to obtain portograms when the less invasive wedged hepatic venography is unsuccessful. Stability also appears be an issue with this prototype software and would require mending, although this is generally outside the scope of prototyping and is more of a step towards production. Portal vein access was obtained by puncturing along the overlaid 3D path in all patients in this study, but perfect portal vein puncture was not achieved in every case. This could be due to inaccuracies caused by patient and/or liver movements, which are drawbacks common to all overlay techniques. Because no notable patient movement was detected in this study, liver movement due to breathing and/or needle pressure was more likely the cause in our cases. To overcome this, real-time motion compensation techniques could potentially be used [14, 15]. In conclusion, adjusting the angle of the liver access set to match the angle of the 3D path determined by the software appears to be a favorable modification to the technique of 3D path planning software assisted TIPS. However, improvements to the software to decrease the rate of failure caused by technical reasons and inaccuracies caused by patient and liver movements are required. In addition, future studies are necessary to determine whether this technique is beneficial. Acknowledgment This paper was made possible by the National Natural Science Fund of China (Grant No. 81371656 & 81171444 to X.L.). Conflict of interests The author Linchao Ye is a paid engineer of Healthcare sector, Siemens Ltd. The remaining authors Jiaywei Tsauo, Xuefeng Luo, and Xiao Li have no real or perceived conflict of interests.
References 1. Boyer TD, Haskal ZJ (2010) The role of transjugular intrahepatic portosystemic shunt (TIPS) in the management of portal hypertension: update 2009. Hepatology 51(1):306 2. Saxon RR, Keller FS (1997) Technical aspects of accessing the portal vein during the TIPS procedure. J Vasc Interv Radiol 8(5):733–744 3. Adamus R, Pfister M, Loose RW (2009) Enhancing transjugular intrahepatic portosystemic shunt puncture by using threedimensional path planning based on the back projection of two two-dimensional portographs. Radiology 251(2):543–547 4. Ferral H, Bilbao JI (2005) The difficult transjugular intrahepatic portosystemic shunt: alternative techniques and ‘‘tips’’ to successful shunt creation. Semin Interv Radiol 22(4):300–308 5. Krajina A, Hulek P, Fejfar T, Valek V (2012) Quality improvement guidelines for transjugular intrahepatic portosystemic shunt (TIPS). Cardiovasc Interv Radiol 35(6):1295–1300 6. Teitelbaum GP, Van Allan RJ, Reed RA, Hanks S, Katz MD (1993) Portal venous branch targeting with a platinum-tipped
J. Tsauo et al.: Modified 3D Software Assisted TIPS
7.
8.
9.
10.
wire to facilitate transjugular intrahepatic portosystemic shunt (TIPS) procedures. Cardiovasc Interv Radiol 16(3):198–200 Foshager M, Ferral H, Finlay D, Castaneda-Zuniga W, Letourneau J (1994) Color Doppler sonography of transjugular intrahepatic portosystemic shunts (TIPS). AJR Am J Roentgenol 163(1):105–111 Warner DL, Owens CA, Hibbeln JF, Ray CE Jr (1995) Indirect localization of the portal vein during a transjugular intrahepatic portosystemic shunt procedure: placement of a radiopaque marker in the hepatic artery. J Vasc Interv Radiol 6(1):87–89 Kee ST, Rhee JS, Butts K, Daniel B, Pauly J, Kerr A et al (1999) MR-guided transjugular portosystemic shunt placement in a swine model. J Vasc Interv Radiol 10(5):529–535 Solomon SB, Magee C, Acker DE, Venbrux AC (1999) TIPS placement in swine, guided by electromagnetic real-time needle tip localization displayed on previously acquired 3-D CT. Cardiovasc Interv Radiol 22(5):411–414
11. Rose SC, Pretorius DH, Nelson TR, Kinney TB, Huynh TV, Roberts AC et al (2000) Adjunctive 3D US for achieving portal vein access during transjugular intrahepatic portosystemic shunt procedures. J Vasc Interv Radiol 11(5):611–621 12. Farsad K, Fuss C, Kolbeck KJ, Barton RE, Lakin PC, Keller FS et al (2012) Transjugular intrahepatic portosystemic shunt creation using intravascular ultrasound guidance. J Vasc Interv Radiol 23(12):1594–1602 13. Debernardi-Venon W, Bandi J, Garcı´a-Paga´n JC, Moitinho E, Andreu V, Real M et al (2000) CO2 wedged hepatic venography in the evaluation of portal hypertension. Gut 46(6):856–860 14. Schweikard A, Glosser G, Bodduluri M, Murphy MJ, Adler JR (2000) Robotic motion compensation for respiratory movement during radiosurgery. Comput Aided Surg 5(4):263–277 15. Clifford MA, Banovac F, Levy E, Cleary K (2002) Assessment of hepatic motion secondary to respiration for computer assisted interventions. Comput Aided Surg 7(5):291–299
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TECHNICAL NOTE
Three-Dimensional Path Planning Software-Assisted Transjugular Intrahepatic Portosystemic Shunt: A Technical Modification Jiaywei Tsauo • Xuefeng Luo • Linchao Ye Xiao Li
•
Received: 22 March 2014 / Accepted: 3 May 2014 Ó Springer Science+Business Media New York and the Cardiovascular and Interventional Radiological Society of Europe (CIRSE) 2014
Abstract Purpose This study was designed to report our results with a modified technique of three-dimensional (3D) path planning software assisted transjugular intrahepatic portosystemic shunt (TIPS). Methods 3D path planning software was recently developed to facilitate TIPS creation by using two carbon dioxide portograms acquired at least 20° apart to generate a 3D path for overlay needle guidance. However, one shortcoming is that puncturing along the overlay would be technically impossible if the angle of the liver access set and the angle of the 3D path are not the same. To solve this problem, a prototype 3D path planning software was fitted with a utility to calculate the angle of the 3D path. Using this, we modified the angle of the liver access set accordingly during the procedure in ten patients. Results Failure for technical reasons occurred in three patients (unsuccessful wedged hepatic venography in two cases, software technical failure in one case). The procedure was successful in the remaining seven patients, and only one needle pass was required to obtain portal vein access in each case. The course of puncture was J. Tsauo X. Luo X. Li (&) Institute of Interventional Radiology, West China Hospital of Sichuan University, 37 Guoxue Lane, Chengdu 610041, Sichuan, China e-mail: [email protected] J. Tsauo e-mail: [email protected] X. Luo e-mail: [email protected] L. Ye Healthcare Sector, Siemens Ltd, Shanghai 201318, China e-mail: [email protected]
comparable to the 3D path in all patients. No procedurerelated complication occurred following the procedures. Conclusions Adjusting the angle of the liver access set to match the angle of the 3D path determined by the software appears to be a favorable modification to the technique of 3D path planning software assisted TIPS. Keywords Transjugular intrahepatic portosystemic shunt Three-dimensional imaging Punctures Computer-assisted
Introduction Transjugular intrahepatic portosystemic shunt (TIPS) is an established interventional procedure used for the management of portal hypertension [1]. To achieve the goal of creating an artificial shunt between the hepatic vein and the portal vein percutaneously, a maneuver more or less commonly referred to as ‘‘portal vein puncture’’ is employed to gain portal vein access. Conventional portal vein puncture is categorically a ‘‘blind puncture’’ as the portal vein cannot be visualized at routine fluoroscopy, and therefore, it is generally considered the most technically difficult step in TIPS creation [2]. Three-dimensional (3D) path planning software was recently introduced by Adamus et al. [3]. Its goal was to facilitate portal vein puncture by using two carbon dioxide (CO2) portograms acquired at least 20° apart to generate a 3D path for overlay needle guidance. The main advantages of this technique includes ease of use, reliable needle guidance, and minimal disruption to normal procedural workflow. However, one shortcoming of this technique is that puncturing along the overlay would be technically impossible to achieve if the angle of the liver
123
J. Tsauo et al.: Modified 3D Software Assisted TIPS
access set and the angle of the 3D path are not precisely the same. This is problematic, because the angle of the 3D path is unknown; thus, it is difficult to accurately adjust the angle of the liver access set. To solve this problem, a new utility used to calculate the angle of the 3D path has been fitted in a prototype 3D path planning software. Using this, we were able to adjust the angle of the liver access set accordingly during the procedure. We report our results with this technique in ten patients.
Materials and Methods Approval from our institutional review board was obtained for this report, and written informed consent was acquired from all patients. Between August 2012 and April 2013, ten patients underwent attempted 3D path planning software-assisted TIPS at our institution, including seven men and three women with a mean age of 48.8 years (range, 35–67 years). Eight patients had hepatitis B virus-induced hepatic cirrhosis and two had alcoholic cirrhosis. Seven patients underwent TIPS for the prevention of variceal rebleeding and three for intractable ascites. Three patients were Child-Pugh class A, five were class B, and two were class C. Before the procedure, all patients had undergone contrast-enhanced, computed-tomography (CT), which revealed patent portal vein and normal anatomy. All procedures were performed by an interventional radiologist with 3 years of experience performing TIPS. The procedures were performed on a flat-panel detector C-arm angiography system (AXIOM Artis dTA; Siemens Healthcare, Forchheim, Germany). With the patients under conscious sedation and local anesthesia, access to the right jugular vein was obtained and the right hepatic vein was catheterized. Wedged hepatic venography in posterioranterior and 30° right anterior oblique projections were performed using an end-hole catheter and 40 mL CO2 during suspended respiration. If the catheter could not be wedged in the hepatic vein, or if the portal vein could not be clearly visualized, balloon occlusion wedged hepatic venography were performed. The CO2 portograms were transferred to a separate research workstation equipped with a prototype 3D path planning software (Siemens Healthcare). The operator plans the path of portal vein puncture by marking the starting point and end point on both portograms (i.e., right hepatic vein and right portal vein), and a corresponding 3D path was automatically produced by the software (Fig. 1). The 3D path was overlaid on live fluoroscopy using the software. This overlay adjusts in real-time to C-arm and table movements, source-to-detector distance, and field of view. Manual correction can be performed through the software if patient
123
Fig. 1 The starting point (hepatic vein) and end point (portal vein) are respectively marked (yellow dot) on two CO2 portograms acquired in posterior-anterior and 30° right anterior oblique projections by using the 3D path planning software. The intersections of the projections lines (orange line) of the marked points reveal its 3D coordinates (green dot), which is automatically connected by the software to obtain the corresponding 3D path (blue line)
Fig. 2 The angle of the liver access set is manually adjusted by the operator to match the angle of the 3D path using a digital protractor (i.e., if the angle of the 3D path determined by the software is 48° then the angle of the liver access would be modified to 132°)
movement is detected during the procedure. The angle of the 3D path was determined by the software, and a Ro¨schUchida liver access set (RUPS-100; Cook, Bloomington, IN) was manually adjusted by the operator to match this angle using a digital protractor (DA-101, Calibeur, Shenzhen, China) (Fig. 2). The modified liver access set was introduced into the hepatic vein, and the puncture needle was advanced along the overlaid 3D path (Fig. 3). After portal vein access has been confirmed by portography, portosystemic pressure gradient (PPG) and portography was measured. The portosystemic tract was dilated
J. Tsauo et al.: Modified 3D Software Assisted TIPS Fig. 3 A 41-year-old man with liver cirrhosis undergoing 3D path planning software assisted TIPS to prevent variceal rebleeding. A The puncture needle is advanced along the overlaid 3D path under fluoroscopy guidance. B Portogram showing that the portal vein access is obtained. C A 10 9 60-mm stent-graft is deployed across the intrahepatic portosystemic tract. D Final venogram obtained after variceal embolization showing successful embolization and antegrade flow through the shunt
with an 8 mm balloon (PowerFlex P3; Cordis Europa N.V., LJ Roden, The Netherlands) and a 10 mm stent-graft (Fluency Plus; Bard, Tempe, Arizona, USA) was placed. The PPG was measured again, and if the gradient was higher than 13 mm Hg, the shunt was dilated with a 10 mm balloon (PowerFlex P3; Cordis Europa N.V.). The final portography was performed, and patients with esophagogastric varices underwent variceal embolization.
Results CO2 portograms were obtained by wedged hepatic venography performed using an end-hole catheter in six patients. Balloon occlusion wedged hepatic venography was required in four patients, but opacification of the portal vein was only achieved in two patients, and thus, the remaining two patients underwent indirect portography.
The eight patients with CO2 portograms underwent 3D path planning software assisted TIPS. However, software technical failure occurred in one patient; thus, this patient and the two who failed wedged hepatic venography underwent conventional TIPS using a liver access set modified based on portograms alone. The procedure was technically successful in all three patients without any procedure-related complications. Two needle passes were required to gain portal vein access in two patients, and three needle passes were required in one patient. The subsequent results exclude these three patients that did not underwent 3D path planning software assisted TIPS. The liver access set was successfully modified to match the angle determined by the software in all seven patients (mean 3D path angle, 30°; range, 21–48°). Using this, we obtained portal vein access in all patients, and only one needle pass was required in each case. The course of puncture was comparable to the 3D path in all patients, of
123
J. Tsauo et al.: Modified 3D Software Assisted TIPS
which portal blood was directly aspirated in four patients and portography confirmed perfect portal vein puncture (the puncture needle did not penetrate the back wall of the portal vein) in these cases. No notable patient movement was detected during portal puncture and thus, no manual correction was required. Only one stent-graft was placed in each patient, and three patients required an additional 10 mm balloon for dilation. The average procedure time (defined as the interval from jugular vein puncture to final portography) was 43 min (range 29–51), and the average fluoroscopy time during this period was 11 min (range 7–16). No procedure-related complications occurred following the procedures.
Discussion Although most TIPS procedures are very straightforward and could be completed within 1 to 2 h, in ‘‘difficult’’ cases (such as distorted anatomy, portal vein thrombosis, or children) and for physicians with less experience, technical failure due to unsuccessful portal vein puncture still constitute a problem [4]. Furthermore, the procedure has a small risk of severe complications associated with portal vein puncture, such as hemoperitoneum, hemobilia, and hepatic artery injury [5]. Thus, from a technical standpoint, researchers have continually focused on improving the accuracy of portal vein puncture [6–12]. In contrast to previously described techniques, 3D path planning software does not involve the placement of the apparatus into the portal vein or hepatic artery, and there is no requirement for additional imaging modalities. Thus, this technique will not increase the invasiveness of TIPS procedure and may be particularly helpful for operators with less experience in medical imaging. However, one shortcoming of this technique is that puncturing along the overlay would be technically impossible to achieve if the angle of the liver access set and the angle of the 3D path are not the same. Thus, we evaluated whether adjusting the angle of the liver access set to match the angle of the 3D path determined by the 3D path planning software was a favorable modification to the technique of 3D path planning software assisted TIPS. Our results showed that there was a rather high rate of failure for technical reasons. The technique seems to efficiently allow access into the portal vein, but perfect puncture could not be achieved in every case. Our results also showed that the length of procedure time was favorable. Unsuccessful opacification of the portal vein by wedged hepatic venography can occur in 15 % of patients with cirrhosis [13]. In these patients, 3D path planning softwareassisted TIPS would be unfeasible, because it is an inherent limitation of this technique. To solve this problem,
123
improvements should perhaps be made to allow this software to support indirect portography, which is a reliable way to obtain portograms when the less invasive wedged hepatic venography is unsuccessful. Stability also appears be an issue with this prototype software and would require mending, although this is generally outside the scope of prototyping and is more of a step towards production. Portal vein access was obtained by puncturing along the overlaid 3D path in all patients in this study, but perfect portal vein puncture was not achieved in every case. This could be due to inaccuracies caused by patient and/or liver movements, which are drawbacks common to all overlay techniques. Because no notable patient movement was detected in this study, liver movement due to breathing and/or needle pressure was more likely the cause in our cases. To overcome this, real-time motion compensation techniques could potentially be used [14, 15]. In conclusion, adjusting the angle of the liver access set to match the angle of the 3D path determined by the software appears to be a favorable modification to the technique of 3D path planning software assisted TIPS. However, improvements to the software to decrease the rate of failure caused by technical reasons and inaccuracies caused by patient and liver movements are required. In addition, future studies are necessary to determine whether this technique is beneficial. Acknowledgment This paper was made possible by the National Natural Science Fund of China (Grant No. 81371656 & 81171444 to X.L.). Conflict of interests The author Linchao Ye is a paid engineer of Healthcare sector, Siemens Ltd. The remaining authors Jiaywei Tsauo, Xuefeng Luo, and Xiao Li have no real or perceived conflict of interests.
References 1. Boyer TD, Haskal ZJ (2010) The role of transjugular intrahepatic portosystemic shunt (TIPS) in the management of portal hypertension: update 2009. Hepatology 51(1):306 2. Saxon RR, Keller FS (1997) Technical aspects of accessing the portal vein during the TIPS procedure. J Vasc Interv Radiol 8(5):733–744 3. Adamus R, Pfister M, Loose RW (2009) Enhancing transjugular intrahepatic portosystemic shunt puncture by using threedimensional path planning based on the back projection of two two-dimensional portographs. Radiology 251(2):543–547 4. Ferral H, Bilbao JI (2005) The difficult transjugular intrahepatic portosystemic shunt: alternative techniques and ‘‘tips’’ to successful shunt creation. Semin Interv Radiol 22(4):300–308 5. Krajina A, Hulek P, Fejfar T, Valek V (2012) Quality improvement guidelines for transjugular intrahepatic portosystemic shunt (TIPS). Cardiovasc Interv Radiol 35(6):1295–1300 6. Teitelbaum GP, Van Allan RJ, Reed RA, Hanks S, Katz MD (1993) Portal venous branch targeting with a platinum-tipped
J. Tsauo et al.: Modified 3D Software Assisted TIPS
7.
8.
9.
10.
wire to facilitate transjugular intrahepatic portosystemic shunt (TIPS) procedures. Cardiovasc Interv Radiol 16(3):198–200 Foshager M, Ferral H, Finlay D, Castaneda-Zuniga W, Letourneau J (1994) Color Doppler sonography of transjugular intrahepatic portosystemic shunts (TIPS). AJR Am J Roentgenol 163(1):105–111 Warner DL, Owens CA, Hibbeln JF, Ray CE Jr (1995) Indirect localization of the portal vein during a transjugular intrahepatic portosystemic shunt procedure: placement of a radiopaque marker in the hepatic artery. J Vasc Interv Radiol 6(1):87–89 Kee ST, Rhee JS, Butts K, Daniel B, Pauly J, Kerr A et al (1999) MR-guided transjugular portosystemic shunt placement in a swine model. J Vasc Interv Radiol 10(5):529–535 Solomon SB, Magee C, Acker DE, Venbrux AC (1999) TIPS placement in swine, guided by electromagnetic real-time needle tip localization displayed on previously acquired 3-D CT. Cardiovasc Interv Radiol 22(5):411–414
11. Rose SC, Pretorius DH, Nelson TR, Kinney TB, Huynh TV, Roberts AC et al (2000) Adjunctive 3D US for achieving portal vein access during transjugular intrahepatic portosystemic shunt procedures. J Vasc Interv Radiol 11(5):611–621 12. Farsad K, Fuss C, Kolbeck KJ, Barton RE, Lakin PC, Keller FS et al (2012) Transjugular intrahepatic portosystemic shunt creation using intravascular ultrasound guidance. J Vasc Interv Radiol 23(12):1594–1602 13. Debernardi-Venon W, Bandi J, Garcı´a-Paga´n JC, Moitinho E, Andreu V, Real M et al (2000) CO2 wedged hepatic venography in the evaluation of portal hypertension. Gut 46(6):856–860 14. Schweikard A, Glosser G, Bodduluri M, Murphy MJ, Adler JR (2000) Robotic motion compensation for respiratory movement during radiosurgery. Comput Aided Surg 5(4):263–277 15. Clifford MA, Banovac F, Levy E, Cleary K (2002) Assessment of hepatic motion secondary to respiration for computer assisted interventions. Comput Aided Surg 7(5):291–299
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