Three-dimensional C-arm CT-guided transjugular intrahepatic portosystemic shunt placement: Feasibility, technical success and procedural time. Eur Radiol. 2016;26:4277-4283. [PMID: 27048535 DOI: 10.1007/s00330-016-4340-4]

Enhancing Cone-Beam CT Image Quality in TIPSS Procedures Using AI Denoising

Purpose: This study evaluates a deep learning-based denoising algorithm to improve the trade-off between radiation dose, image noise, and motion artifacts in TIPSS procedures, aiming for shorter acquisition times and reduced radiation with maintained diagnostic quality. Methods: In this retrospective study, TIPSS patients were divided based on CBCT acquisition times of 6 s and 3 s. Traditional weighted filtered back projection (Original) and an AI denoising algorithm (AID) were used for image reconstructions. Objective assessments of image quality included contrast, noise levels, and contrast-to-noise ratios (CNRs) through place-consistent region-of-interest (ROI) measurements across various critical areas pertinent to the TIPSS procedure. Subjective assessments were conducted by two blinded radiologists who evaluated the overall image quality, sharpness, contrast, and motion artifacts for each dataset combination. Statistical significance was determined using a mixed-effects model (p ≤ 0.05). Results: From an initial cohort of 60 TIPSS patients, 44 were selected and paired. The mean dose-area product (DAP) for the 6 s acquisitions was 5138.50 ± 1325.57 µGy·m2, significantly higher than the 2514.06 ± 691.59 µGym2 obtained for the 3 s series. CNR was highest in the 6 s-AID series (p < 0.05). Both denoised and original series showed consistent contrast for 6 s and 3 s acquisitions, with no significant noise differences between the 6 s Original and 3 s AID images (p > 0.9). Subjective assessments indicated superior quality in 6 s-AID images, with no significant overall quality difference between the 6 s-Original and 3 s-AID series (p > 0.9). Conclusions: The AI denoising algorithm enhances CBCT image quality in TIPSS procedures, allowing for shorter scans that reduce radiation exposure and minimize motion artifacts.

CBCT-based three-dimensional dual-phase vascular image fusion: a novel technique for interventional real-time TIPS guidance

BACKGROUND

Due to the invisibility of the portal vein (PV), how to puncture the PV accurately and safely in transjugular intrahepatic portosystemic shunt (TIPS) creation remains a challenge of the procedure.

OBJECTIVES

We aimed to provide the first evaluation of the safety, feasibility, and efficiency of cone beam computed tomography (CBCT)-based three-dimensional (3D) dual-phase vascular image fusion for interventional real-time guided PV puncture during TIPS procedures.

MATERIALS AND METHODS

From January 2021 to May 2021, 13 patients undergoing TIPS were prospectively enrolled in this study. Images of the hepatic artery (HA) and PV in 3D were acquired and overlaid on interventional fluoroscopy images in a dual-phase display mode for real-time PV puncture guidance. The number of PV puncture attempts, puncture time, overlaid image accuracy, dose area product, fluoroscopy time, and interventional complications were recorded.

RESULTS

Portal vein puncture guided by CBCT-based 3D dual-phase vascular image fusion was successfully performed on 92.3% (12/13) patients. The mean number of PV puncture attempts was 1.8 ± 0.7 (1-3). The mean puncture time and fluoroscopy time was 3.5 ± 1.2 (2-6) min and 25.1 ± 9.4 (15-45) min, respectively. The mean dose area product was 39.49 ± 7.88 (28.81-52.87) mGym2. The error between the reference position of the fusion image and the interventional PV angiography image was less than 0.5 cm. No interventional complication was observed.

CONCLUSION

Our results show that 3D dual-phase vascular image fusion might be a safe and feasible technique for interventional real-time guided PV puncture during TIPS. This novel technique might help to reduce the number of PV puncture attempts and the puncture time as well as lower the risks of interventional complications.

Advanced portal venous access techniques for transjugular intrahepatic portosystemic shunt placement

Introduction

Transjugular intrahepatic portosystemic shunt (TIPS) placement is a well-established but technically challenging procedure for the management of sequelae of end-stage liver disease. Performed essentially blindly, traditional fluoroscopically guided TIPS placement requires multiple needle passes and prolonged radiation exposure to achieve successful portal venous access, thus increasing procedure time and the risk of periprocedural complications. Several advanced image-guided portal access techniques, including intracardiac echocardiography (ICE)-guided access, cone-beam CT (CBCT)-guided access and wire-targeting access techniques, can serve as alternatives to traditional CO₂ portography-based TIPS creation.

Methods

A literature search was performed on the electronic databases including MEDLINE and Embase, from 2000 to the present to identify all relevant studies. The reference list also included studies identified manually, and studies referenced for other purposes.

Findings

The main benefit of these advanced access techniques is that they allow the operator to avoid essentially blind portal punctures, and the ability to visualise the target, thus reducing the number of required needle passes. Research has shown that ICE-guided access can decrease the radiation exposure, procedure time and complication rate in patients undergoing TIPS placement. This technique is particularly useful in patients with challenging portal venous anatomy. However, ICE-guided access requires additional equipment and possibly a second operator. Other studies have shown that CBCT-guided access, when compared with traditional fluoroscopy-guided access, provides superior visualisation of the anatomy with similar amount of radiation exposure and procedure time. The wire-targeting technique, on the other hand, appears to offer reductions in procedure time and radiation exposure by enabling real-time guidance. However, this technique necessitates percutaneous injury to the liver parenchyma in order to place the target wire.

Conclusion

Advanced portal access techniques have certain advantages over the traditional fluoroscopically guided TIPS access. To date, few studies have compared these advanced guided access options, and further research is required.

Use of Virtual Target Fluoroscopic Display of Three-Dimensional CO2 Wedged Hepatic Vein Portography for TIPS Placement

PURPOSE

To describe and evaluate an image fusion technique for the portal vein puncture guidance during TIPS procedure: a three-dimensional (3D) virtual target fluoroscopic display obtained with an automated 3D carbon dioxide wedged hepatic vein portography (3D CO₂-WHVP).

MATERIALS AND METHODS

All the 37 TIPS creations performed in our institution between 3/2017 and 12/2018 were retrospectively reviewed. Seventeen procedures were guided using the 3D CO₂-WHVP technique (group 1) and were compared with the other 20 procedures performed under conventional 2D fluoroscopic guidance (group 2). Image acquisition for the 3D CO₂-WHVP consisted of combining a CBCT acquisition and an automatic CO₂ injection. Once located on the multiplanar reformatted images of the CBCT acquisition, the portal bifurcation was manually segmented to create a virtual target that was overlaid onto live fluoroscopy allowing a real-time 3D guidance during portal vein puncture.

RESULTS

Primary success was 100% in group1 and 95% in group2. Median intervention length, fluoroscopy time and dose area product (DAP) were, respectively, 124 min [IQR 94-137], 40 min [IQR 26-52] and 12140 cGy.cm² [IQR 10147-18495] in group 1 and 146 min [IQR 118-199], 40 min [IQR 36-60] and 13290 cGy.cm² [IQR 10138-19538] in group 2. No technical parameter was significantly different between the two groups. Intraprocedural complication rate was 0% in group 1 and 20% in group 2 (p = 0.05).

CONCLUSION

Three-dimensional virtual target fluoroscopic display using a CBCT-acquired CO₂ wedged portography is an effective and safe technique to ease intrahepatic puncture of the portal vein during TIPS procedures.

Transjugular intrahepatic portosystemic shunt placement: portal vein puncture guided by 3D/2D image registration of contrast-enhanced multi-detector computed tomography and fluoroscopy

Background

To assess the technical feasibility, success rate, puncture complications and procedural characteristics of transjugular intrahepatic portosystemic shunt (TIPS) placement using a three-dimensional vascular map (3D-VM) overlay based on image registration of pre-procedural contrast-enhanced (CE) multi-detector computed tomography (MDCT) for portal vein puncture guidance.

Materials and methods

Overall, 27 consecutive patients (59 ± 9 years, 18male) with portal hypertension undergoing elective TIPS procedure were included. TIPS was guided by CE-MDCT overlay after image registration based on fluoroscopic images. A 3D-VM of the hepatic veins and the portal vein was created based on the pre-procedural CE-MDCT and superimposed on fluoroscopy in real-time. Procedural characteristics as well as hepatic vein catheterization time (HVCT), puncture time (PT), overall procedural time (OPT), fluoroscopy time (FT) and the dose area product (DAP) were evaluated. Thereafter, HVCT, PT, OPT and FT using 3D-VM (61 ± 9 years, 14male) were compared to a previous using classical fluoroscopic guidance (53 ± 9 years, 21male) for two interventional radiologist with less than 3 years of experience in TIPS placement.

Results

All TIPS procedure using of 3D/2D image registered 3D-VM were successful with a significant reduction of the PSG (p < 0.0001). No clinical significant complication occurred. HVCT was 14 ± 11 min, PT was 14 ± 6 min, OPT was 64 ± 29 min, FT was 21 ± 12 min and DAP was 107.48 ± 93.84 Gy cm². HVCT, OPT and FT of the interventionalist with less TIPS experience using 3D/2D image registered 3D-VM were statistically different to an interventionalist with similar experience using fluoroscopic guidance (p_HVCT = 0.0022; p_OPT = 0.0097; p_FT = 0.0009). PT between these interventionalists was not significantly different (p_PT = 0.2905).

Conclusion

TIPS placement applying registration-based CE-MDCT vessel information for puncture guidance is feasible and safe. It has the potential to improve hepatic vein catherization, portal vein puncture and radiation exposure.

Transjugular intrahepatic portosystemic shunt in cirrhosis: An exhaustive critical update

More than five decades after it was originally conceptualized as rescue therapy for patients with intractable variceal bleeding, the transjugular intrahepatic portosystemic shunt (TIPS) procedure continues to remain a focus of intense clinical and biomedical research. By the impressive reduction in portal pressure achieved by this intervention, coupled with its minimally invasive nature, TIPS has gained increasing acceptance in the treatment of complications of portal hypertension. The early years of TIPS were plagued by poor long-term patency of the stents and increased incidence of hepatic encephalopathy. Moreover, the diversion of portal flow after placement of TIPS often resulted in derangement of hepatic functions, which was occasionally severe. While the incidence of shunt dysfunction has markedly reduced with the advent of covered stents, hepatic encephalopathy and instances of early liver failure continue to remain a significant issue after TIPS. It has emerged over the years that careful selection of patients and diligent post-procedural care is of paramount importance to optimize the outcome after TIPS. The past twenty years have seen multiple studies redefining the role of TIPS in the management of variceal bleeding and refractory ascites while exploring its application in other complications of cirrhosis like hepatic hydrothorax, portal hypertensive gastropathy, ectopic varices, hepatorenal and hepatopulmonary syndromes, non-tumoral portal vein thrombosis and chylous ascites. It has also been utilized to good effect before extrahepatic abdominal surgery to reduce perioperative morbidity and mortality. The current article aims to review the updated literature on the status of TIPS in the management of patients with liver cirrhosis.

Application of a Metal Artifact Reduction Algorithm for C-Arm Cone-Beam CT: Impact on Image Quality and Diagnostic Confidence for Bronchial Artery Embolization

OBJECTIVE

The objective of this study was to evaluate the potential benefit of a dedicated cone-beam-CT streak metal artifact removal technique (SMART) in terms of both image quality and diagnostic confidence in patients undergoing bronchial artery embolization.

METHODS

A total of 17 patients were included in this retrospective study. The SMART algorithm was applied to images containing streak artifacts generated by a radiopaque intra-arterial catheter tip. Quantitative evaluation of artifact severity was performed via measurement of the Hounsfield units along a closed loop surrounding the catheter tip and was conducted in the frequency domain following the application of the discrete Fourier transform to the measured data. A high proportion of power in the low frequencies of the resulting spectrum indicated a high level of streak artifacts. Qualitative evaluation of diagnostic confidence was performed using a 4-point Likert scale.

RESULTS

Both quantitative and qualitative evaluation demonstrated a significant reduction in artifact severity using the SMART algorithm. Quantitative evaluation demonstrated a mean artifact reduction of 22.5% using SMART compared to non-SMART images (p < 0.001). Qualitative evaluation demonstrated the greatest artifact reduction at the inner and outer aortic curvature, as well as immediately surrounding the tip of the catheter. In 6 of 17 cases, the use of the SMART algorithm yielded additional clinical information, increasing mean diagnostic confidence from 3.17 to 3.78 (p < 0.001).

CONCLUSION

The SMART algorithm allows for efficient reduction of metal artifacts introduced by radiopaque catheter tips during cone-beam CT. Using this algorithm, diagnostic images of the aortic arch were significantly improved both quantitatively and qualitatively, yielding clinically relevant levels of enhanced diagnostic confidence. These results demonstrate that the SMART algorithm improves diagnostic and clinical characterization of the course of bronchial arteries on CBCT images, potentially improving the accuracy and clinical efficacy of bronchial artery embolization.

LEVEL OF EVIDENCE

3.

Clinical Experience with Real-Time 3-D Guidance Based on C-Arm-Acquired Cone-Beam CT (CBCT) in Transjugular Intrahepatic Portosystemic Stent Shunt (TIPSS) Placement

PURPOSE

The aim of this study was to evaluate the feasibility of cone-beam computed tomography (CBCT)-based real-time 3-D guidance of TIPSS placement and its positioning compared to standard guiding methods.

MATERIALS AND METHODS

In a prospective, randomized, consecutive study design from 2015 to 2017, we included 21 patients in the CBCT guided group and 15 patients in the ultrasound (US) guided group. The prospective groups were compared in terms of success rate of intervention, portal vein puncture/procedure time, number of puncture attempts and applied dose. We furthermore retrospectively analyzed the last 23 consecutive cases with fluoroscopic guided portal vein puncture in terms of success rate, procedure time and applied dose, as it has been the standard method before US guidance.

RESULTS

The median number of puncture attempts (CBCT: n = 2, US: n = 4, p = 0.249) and the mean puncture time (CBCT: 32 ± 45 min, US: 36 ± 45 min, p = 0.515) were not significantly different. There were furthermore no significant differences in the mean time needed for the total TIPSS procedure (CBCT: 115 ± 52 min, US: 112 ± 41 min, fluoroscopy: 110 ± 33 min, p = 0.996). The mean applied dose of the complete procedure also showed no statistically significant differences (CBCT: 563 ± 289 Gy·cm², US: 322 ± 186 Gy·cm², fluoroscopy: 469 ± 352 Gy·cm², p = 0.069). There were no image guidance related complications.

CONCLUSION

Real-time 3-D needle guidance based on CBCT is feasible for TIPSS placement. In terms of puncture attempts, duration and dose, CBCT guidance was not inferior to the control groups and may be a valuable support for interventionists in TIPSS procedures.

Transjugular intrahepatic portosystemic shunt creation: three-dimensional roadmap versus CO2 wedged hepatic venography

OBJECTIVES

The blind portal vein puncture remains the most challenging step during transjugular intrahepatic portosystemic shunt (TIPS) creation. We performed a prospective randomised clinical trial to compare three-dimensional (3D) roadmap with CO₂ wedged hepatic vein portography for portal vein puncture guidance.

METHODS

Between March 2017 and May 2017, 30 patients were enrolled and randomly allocated to the study group (3D roadmap) or the control group (CO₂ wedged hepatic vein portography).

RESULTS

Technical success of TIPS procedures was achieved in all 30 patients. The mean number of needle passes was significantly lower in the study group (2.0 ± 1.0) compared to the control group (3.7 ± 2.5; p = 0.021). A total of six (40%) patients in the study group and three (20%) in the control group required only one puncture for the establishment of TIPS. There were no significant differences in total fluoroscopy time (p = 0.905), total procedure time (p = 0.199) and dose-area product (p = 0.870) between the two groups.

CONCLUSIONS

3D roadmap is a safe and technically feasible means for portal vein puncture guidance during TIPS creation, equivalent in efficacy to CO₂ wedged hepatic vein portography. This technique could reduce the number of needle passes, thereby simplifying the TIPS procedure.

KEY POINTS

• 3D roadmap can be used to guide portal vein puncture. • Compared with CO ₂ venography, 3D roadmap reduced the number of needle passes. • 3D roadmap has a potential to simplify the TIPS procedure.

Utility of cone-beam computed tomography in the assessment of the porto-spleno-mesenteric venous system

The common diagnostic tools available to evaluate the porto-spleno-mesenteric venous (PSMV) system provide either good hemodynamic information with limited morphological details [e.g., ultrasonography (US)] or excellent tomographic display of the anatomy with limited information about flow patterns [e.g., multidetector computed tomography (MDCT) and magnetic resonance imaging]. Although catheter-directed selective digital subtraction angiography (DSA) can provide excellent information about flow at a high temporal resolution and can generate images at a high spatial resolution, this technique is often limited by a lack of cross-sectional detail. In the assessment of the PSMV system, DSA is also limited by dilution of contrast and motion artefacts. Combining venous phase cone-beam computed tomography (CBCT) with DSA can generate high-quality tomographic data, which allows detailed evaluation of venous tributaries and flow patterns within the splenic, superior mesenteric, and inferior mesenteric venous systems individually. This enables clinicians to better understand the impact of nonobstructive resistance to flow (e.g., as in patients with cirrhosis) and obstructive resistance to flow (e.g., as in patients with thrombosis) within each system and plan treatment accordingly. In this review, we discuss the limitations of common diagnostic methods and the role venous CBCT in combination with DSA can play in assessing the PSMV system.