A new angiographic imaging platform reduces radiation exposure for patients with liver cancer treated with transarterial chemoembolization

Tracking and Navigation Technologies for Image-Guided Trans-Arterial Interventions

Trans-arterial interventions are an increasingly utilized approach for diagnosing and treating a wide range of pathologies, providing superior patient outcomes compared to traditional open surgical methods. Recent advancements in tracking and navigation technologies have significantly refined these interventions, enhancing procedural precision and success. Advanced imaging modalities, such as fluoroscopy, cone beam computed tomography (CBCT), and intravascular ultrasound (IVUS), are frequently used strategies offering critical real-time guidance. Although fluoroscopy remains the primary choice for many procedures, advancements in CBCT and IVUS have enabled the delivery of detailed volumetric and intravascular imaging while reducing radiation exposure. Aiming to enhance imaging capabilities further, image fusion and augmented reality technologies show substantial potential for integrating multiple datasets into cohesive models, improving instrument tracking and spatial orientation during interventions. Innovations in navigation systems, including electromagnetic, fiberoptic, and robotic navigation, provide additional tracking capabilities for enhanced intra-arterial navigation. This article will review the current advancements in imaging, tracking, navigation, and image fusion technologies and explore their utility in enhancing trans-arterial interventions.

Radiation dose during transarterial chemoembolization and associated factors

PURPOSE

To provide detailed reports on radiation doses during transarterial chemoembolization (TACE) in the cone-beam computed tomography (CBCT) era and to identify the associated factors.

METHODS

This retrospective study included 385 consecutive patients who underwent initial conventional TACE for hepatocellular carcinoma (HCC) between January 2016 and December 2017. In most cases, CBCT was performed at the common hepatic artery or celiac axis to confirm the location of the tumor and the three-dimensional hepatic artery anatomy. Superselective TACE was performed for all technically feasible cases. Information on total dose area product (DAP), total cumulative air kerma (CAK), fluoroscopy time, and DAP and CAK of each digital subtraction angiography (DSA) and CBCT scan was recorded. Multiple linear regression analysis was performed to identify the factors associated with increased DAP during TACE.

RESULTS

The mean values of total DAP and CAK were 165.2 ± 81.2 (Gy·cm²) and 837.1 ± 571.0 (mGy), respectively. The mean fluoroscopy time was 19.1 ± 10.3 min. The mean DAP caused by fluoroscopy, DSA, and CBCT was 51.8 ± 43.9, 28.0 ± 24.1, and 83.9 ± 42.1 Gy·cm², respectively. Male sex, a high body mass index, largest tumor size > 3 cm, presence of aberrant right and left hepatic arteries, and superselective TACE were identified as independent predictors of increased total DAP during TACE.

CONCLUSION

We were able to provide detailed reports on radiation doses during TACE and associated factors.

Exploring software navigation tools for liver tumour angiography: a scoping review

INTRODUCTION

Liver cancer presents a growing global health concern, necessitating advanced approaches for intervention. This review investigates the use and effectiveness of software navigation in interventional radiology for liver tumour procedures.

METHODS

In accordance with Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines, a scoping review was conducted of the literature published between 2013 and 2023 sourcing articles through MEDLINE, Scopus, CINAHL and Embase. Eligible studies focused on liver cancer, utilised cone-beam computed tomography (CBCT), and employed software for intervention. Twenty-one articles were deemed eligible for data extraction and analysis.

RESULTS

Categorised by type, software applications yielded diverse benefits. Feeder detection software significantly enhanced vessel identification, reducing non-target embolisation by up to 43%. Motion correction software demonstrated a 20% enhancement in image quality, effectively mitigating breathing-induced motion artefacts. Liver perfusion software facilitated efficient tumour targeting while simultaneously reducing the occurrence of side effects. Needle guide software enabled precise radiofrequency ablation needle placement. Additionally, these software applications provided detailed anatomical simulations. Overall, software integration resulted in shorter procedures, reduced radiation exposure and decreased contrast media usage.

CONCLUSION

This scoping review highlights the innovative yet relatively underexplored role of software navigation for liver tumour procedures. The integration of software applications not only enhances procedural efficiency but also bolsters operator confidence, and contributes to improved patient outcomes. Despite the current lack of uniformity and standardisation, these software-driven advancements hold significant promise for transforming liver tumour interventions. To realise these benefits, further research is needed to explore the clinical impact and optimal utilisation of software navigation tools in interventional radiology.

Retrospective Analysis of Doses Delivered during Embolization Procedures over the Last 10 Years

Background: This study aimed to retrospectively analyze dosimetric indicators recorded since 2012 for thoracic, abdominal or pelvic embolizations to evaluate the contribution of new tools and technologies in dose reduction. Methods: Dosimetric indicators (dose area product (DAP) and air kerma (AK)) from 1449 embolizations were retrospectively reviewed from August 2012 to March 2022. A total of 1089 embolizations were performed in an older fixed C-Arm system (A1), 222 in a newer fixed C-Arm system (A2) and 138 in a 4DCT system (A3). The embolization procedures were gathered to compare A1, A2 and A3. Results: DAP were significantly lower with A2 compared to A1 for all procedures (median −50% ± 5%, p < 0.05), except for uterine elective embolizations and gonadal vein embolization. The DAP values were significantly lower with A3 than with A1 (p < 0.001). CT scan was used for guidance in 90% of embolization procedures. Conclusions: The last C-Arm technology allowed a median reduction of 50% of the X-ray dose. The implementation of a CT scan inside the IR room allowed for more precise 3D-guidance with no increase of the dose delivered.

Radiation dose reduction during adrenal vein sampling using a new angiographic imaging technology

To compare the patient radiation doses during angiographic selective adrenal vein sampling (AVS) before and after an imaging technology upgrade. In this retrospective single-center-study, cumulative air kerma (AK), cumulative dose area product (DAP), fluoroscopy time and contrast agent dosage were recorded from 70 patients during AVS. 35 procedures were performed before and 35 after an imaging processing technology upgrade. Mean values were calculated and compared using an unpaired student’s t-test. DSA image quality was assessed independently by two blinded readers using a four-point Likert scale (1 = poor; 4 = excellent) and compared using Wilcoxon signed-rank test. After the technology upgrade we observed a significant reduction of 35% in AK (1.7 ± 0.7 vs. 1.1 ± 0.7 Gy, p = 0.01) and a significant reduction of 28% in DAP (235.1 ± 113 vs. 170.1 ± 94 Gy*cm², p = 0.01) in comparison to procedures before the upgrade. There were no significant differences between the number of exposure frames (143 ± 86 vs. 132 ± 61 frames, p = 0.53), fluoroscopy time (42 ± 23 vs. 36 ± 18 min, p = 0.22), or the amount of contrast medium used (179.5 ± 84 vs. 198.1 ± 109 ml, p = 0.41). There was also no significant difference regarding image quality (3 (2–4) vs. 3 (2–4), p = 0.67). The angiographic imaging technology upgrade significantly decreases the radiation dose during adrenal vein sampling without increasing time of fluoroscopy or contrast volume and without compromising image quality.

New imaging technology system reduces patient radiation dose during peripheral arterial endovascular interventions

BACKGROUND

Radiation exposure and imaging quality are among the main concerns in endovascular procedures. The Clear VD11 PURE platform technology system (Siemens Healthineers, Erlangen, Germany) has been reported to lower the radiation dose and improve image quality. In the present study, we evaluated whether the radiation dose during peripheral arterial endovascular procedures had decreased after implementation of this new imaging system.

METHODS

The patient characteristics (age, gender, body mass index [BMI]), procedure type (diagnostic, balloon angioplasty, atherectomy, stenting), body location (aortoiliac, superficial femoral artery, tibial artery), reference air kerma (RAK), kerma area product (KAP), and fluoroscopy time (FT) were recorded during peripheral artery interventions performed 1 year before (group A) and 1 year after (group B) the CLEAR system upgrade. The procedures were performed in an Artis zeego hybrid room (Siemens Healthineers) with the same providers. A general linear model was used to estimate the average difference between groups adjusted by procedure type and patient age, gender, and BMI. Additionally, to control for variations in case complexity, groups A and B were matched by age, gender, BMI, lesion location, and intervention type. Propensity score matching and a paired t test were used to compare the KAP, RAK, and FT stratified by single intervention procedures.

RESULTS

A total of 487 endovascular procedures were performed: 209 in group A and 278 in group B. A total of 111 single intervention procedures from each group were matched (1:1), with a mean age of 61 ± 8 years and a BMI of 26.5 ± 4 kg/m². The median KAP, RAK, and FT for group A were 28.8 Gy · cm² (interquartile range [IQR], 24-34 Gy · cm²), 146 mGy (IQR, 123-173 mGy), and 12 minutes (IQR, 10-14 minutes), respectively. The median KAP, RAK, and FT for group B were 18.3 Gy · cm² (IQR, 16-22 Gy · cm²), 71.2 mGy (IQR, 60-85 mGy), and 10.4 minutes (IQR, 9-12 minutes), respectively. The KAP, RAK, and FT were significantly decreased in group B by 24% (P = .005), 41% (P < .001), and 22% (P = .002), respectively, compared with the values for group A. Stratified by single intervention procedures, the KAP and RAK had decreased significantly in group B (36% [P = .002] and 51% [P < .001], respectively) compared with group A. The FT decrease of 13% in group B was not statistically significant (P = .20).

CONCLUSIONS

Use of the Clear VD11 PURE platform system (Siemens Healthineers) reduced the patient radiation dose by 51% during endovascular peripheral interventions. The similar FTs for the matched single intervention procedures before and after the upgrade indicated consistent case complexity and surgeon practice. This platform appears to be an effective system for lowering the radiation dose.

Patient radiation dose during angiography and embolization for abdominal hemorrhage: the influence of CT angiography, fluoroscopy system, patient and procedural variables

Background

Angiography and embolization (AE) is a lifesaving, high radiation dose procedure for treatment of abdominal arterial hemorrhage (AAH). Interventional radiologists have utilized pre-procedure CT angiography (CTA) and newer fluoroscopic systems in an attempt to reduce radiation dose and procedure time.

Purpose

To study the factors contributing to the radiation dose of AE for AAH and to compare to the reference standard.

Materials and methods

This retrospective single-centre observational cohort study identified 154 consecutive AE procedures in 138 patients (median age 65 years; interquartile range 54–77; 103 men) performed with a C-arm fluoroscopic system (Axiom Artis DTA or Axiom Artis Q (Siemens Healthineers)), between January 2010 and December 2017. Parameters analysed included: demographics, fluoroscopy system, bleeding location, body mass index (BMI), preprocedural CT, air kerma-area product (PKA), reference air kerma (K_a,r), fluoroscopy time (FT) and the number of digital subtraction angiography (DSA) runs. Factors affecting dose were assessed using Mann–Whitney U, Kruskal–Wallis one-way ANOVA and linear regression.

Results

Patients treated with the new angiographic system (NS) had a median PKA, median K_a,r, Q3 PKA and Q3 K_a,r that were 74% (p < 0.0005), 66%(p < 0.0005), 55% and 52% lower respectively than those treated with the old system (OS). This dose reduction was consistent for each bleeding location (upper GI, Lower GI and extraluminal). There was no difference in PKA (p = 0.452), K_a,r (p = 0.974) or FT (p = 0.179), between those who did (n = 137) or did not (n = 17) undergo pre-procedure CTA. Other factors significantly influencing radiation dose were: patient BMI and number of DSA runs. A multivariate model containing these variables accounts for 15.2% of the variance in K_a,r (p < 0.005) and 45.9% of the variance of PKA (p < 0.005).

Conclusion

Radiation dose for AE in AAH is significantly reduced by new fluoroscopic technology. Higher patient body mass index is an independent key parameter affecting patient dose. Radiation dose was not influenced by haemorrhage site or performance of pre-procedure CTA.

Predictors of radiation dose for uterine artery embolisation are angiography system-dependent

This study sought to achieve radiation dose reductions for patients receiving uterine artery embolisation (UAE) by evaluating radiation dose measurements for the preceding generation (Allura) and upgraded (Azurion) angiography system. Previous UAE regression models in the literature could not be applied to this centre's practice due to being based on different angiography systems and radiation dose predictor variables. The aims of this study were to establish whether radiation dose is reduced with the upgraded angiography system and to develop a regression model to determine predictors of radiation dose specific to the upgraded angiography system. A comparison between Group I (Allura,n= 95) and Group II (Azurion,n= 95) demonstrated a significant reduction in kerma-area product (KAP) and Ka, r (reference air kerma) by 63% (143.2 Gy cm²vs 52.9 Gy cm²;P< 0.001,d= 0.8) and 67% (0.6 Gy vs 0.2 Gy;P< 0.001,d= 0.8), respectively. The multivariable linear regression (MLR) model identified the UAE radiation dose predictors for KAP on the upgraded angiography system as total fluoroscopy dose, Ka, r, and total uterus volume. The predictive accuracy of the MLR model was assessed using a Bland-Altman plot. The mean difference was 0.39 Gy cm²and the limits of agreement were +28.49 and -27.71 Gy cm², and thus illustrated no proportional bias. The resultant MLR model was considered system-dependent and validated the upgraded angiography system and its advance capabilities to significantly reduce radiation dose. Interventional radiologist and interventional radiographer familiarisation of the system's features and the implementation of the newly established MLR model would further facilitate dose optimisation for all centres performing UAE procedures using the upgraded angiography system.

Comparison of radiation doses between hepatic artery infusion chemotherapy and transarterial chemoembolization for liver cancer

Objective

To analyze the radiation dose received by patients during hepatic artery infusion chemotherapy (HAIC) and transarterial chemoembolization (TACE) procedures and the related influencing factors.

Methods

Data of 162 cases in the HAIC group and 230 cases in the TACE group were collected. The included covariates were Age (<45/45–59/≥60 years), BMI levels (underweight/normal weight/obesity), focus Dye of tumor (present/absent), lesion size (<5cm/≥5cm), superselection (present/absent), hepatic vascular variation (present/absent). The endpoints were postoperative dose-area product (DAP), exposure time and Air kerma (AK).

Results

Of all included patients, the HAIC group patients were younger than those in the TACE group (P ​= ​0.028). The proportion of patients with large lesions in the HAIC group was higher than the TACE group (45.7% vs. 33.9%, P ​= ​0.019). The proportion of patients who had superselection was lower in the HAIC group as compared to the TACE group (61.7% vs. 82.2%, P ​< ​0.001). Generally, the HAIC group has lower DAP, exposure time and AK by 36.3% (P ​< ​0.001), 38.2% (P ​< ​0.001), and 41.3% (P ​< ​0.001) than the TACE group, respectively. Linear regression analysis showed the procedure method (HAIC/TACE, P ​< ​0.001), type of DSA machine (Pheno/FD20, P ​< ​0.001), BMI levels (P ​< ​0.001), age (P ​= ​0.021), lesion size (<5cm/≥5 ​cm, P ​= ​0.031) significantly correlated with low DAP. In the HAIC group, the type of DSA machine and BMI correlated with the radiation dose, while in the TACE group, the type of DSA machine, BMI, and lesion size correlated with the radiation dose.

Conclusion

Compared with TACE, HAIC enables doctors and patients to receive lower radiation doses. Obese patients in both HAIC and TACE groups increase the radiation exposure in interventional doctors and patients, but large lesions only affect the radiation dose in the TACE procedure.

Local dose reference levels during transarterial chemoembolization procedure

The aim of this study was to develop local diagnostic reference levels (LDRL) during Transarterial chemoembolization (TACE). This cross-sectional study reports radiation dose indicators of 108 patients in a Mexican hospital, obtained over a period of 35 months. Kerma-area product (P_KA), air-kerma at the reference point (K_{a, r}), and descriptive statistical analysis were examined according to sociodemographic characteristics of the sample patients. The LDRL obtained were then compared to a similar international framework. The present study contributes to the establishment of a TACE LDRL and identifies significant correlations among radiology factors and dosimetric quantities obtained.

Patients' Radiation Shielding in Interventional Radiology Settings: A Systematic Review

As a result of the increasing risk of developing radiation-related complications, many approaches aimed at reducing this risk and enhancing the outcomes of the patient, doctor or device operator have been developed. In this systematic review, we aim to discuss previous investigations that studied patient shielding or protection within the context of selected interventional radiology procedures. We included original studies that used K_a,r, and P_KA for the assessment of the outcomes of two procedures: transjugular intrahepatic portosystemic shunt creation (TIPS) and hepatic arterial chemoembolization (HAE). A thorough search strategy was conducted on relevant databases to identify all relevant studies. We included 13 investigations, including 12 cross-sectional studies and one randomized controlled trial. Significant diversity was found among all these studies in terms of the used modalities, which made them hard to compare. However, almost all studies agreed that using novel imaging and interventional modalities is useful when obtaining better outcomes and reducing patient radiation exposure. The use of ultrasound-guided procedures and providing adequate lead curtains has also been recommended by the identified studies in order to minimize the frequency of radiation exposure. The reported K_a,r, and P_KA were also variable between studies and were discussed within this study. Our findings indicate that unified guidelines for patient radiation shielding should be urgently investigated.

Radiation dose reduction capabilities of a new C-arm system with optimized hard- and software

PURPOSE

To assess the radiation dose reduction capabilities and the image quality of a new C-arm system in comparison to a standard C-arm system.

METHOD

Prospective, randomized, IRB approved two-arm trial design. 49 consecutive patients with primary or secondary liver cancer were treated with transarterial chemoembolization (TACE) on two different angiography units. 28 patients were treated on a conventional angiography unit B, 21 patients on unit A which provides improved hardware and optimized image processing algorithms. Dose area product (DAP) and fluoroscopy time were recorded. DSA image quality of all procedures was assessed on a four-rank-scale by two independent and blinded readers.

RESULTS

Both cohorts showed no significant differences with regard to patient characteristics, tumor burden and fluoroscopy time. The new system resulted in a statistically significant reduction of cumulative DAP of 72% compared to the old platform (median 76 vs. 269 Gy*cm2). Individually, Fluoro-DAP and DSA-DAP decreased by 48% and 77% (p = 0.012 and p < 0.01), respectively. No statistically significant differences in DSA image quality were found between the two imaging platforms.

CONCLUSIONS

The new C-arm system significantly reduced radiation exposure for TACE procedures without increased radiation time or negative impact on DSA image quality. The combination of optimized hardware and software yields the highest radiation dose reduction and is of utmost importance for patients and interventionalists.

Performance of Double-Arm Digital Subtraction Angiography (DSA)-Guided and C-Arm-Guided Percutaneous Kyphoplasty (PKP) to Treat Senile Osteoporotic Vertebral Compression Fractures

Background

Osteoporotic vertebral compression fracture (OVCF) is a common fracture in the elderly. Conservative treatment requires prolonged bedding, which may lead to serious complications. To explore optimized use of percutaneous kyphoplasty (PKP) in the treatment of senile osteoporotic thoracolumbar vertebral compression fractures, in this study, we used C-arm-guided and double-arm digital subtraction angiography (DSA)-guided PKP to treat OVCF in elderly patients and analyzed the effective recovery.

Material/Methods

In all, 60 patients who presented with osteoporotic vertebral compression fractures at our hospital between July 2017 and February 2019 were analyzed. They were randomly divided into C-arm-guided group and the double-arm DSA-guided groups. Both groups were treated with percutaneous kyphoplasty.

Results

A pain VAS score analysis revealed that there was no significant difference between the two groups before surgery (P>0.05). After surgery, the VAS scores showed a significant difference between the C-arm-guided group and the double-arm DSA-guided PKP treatment group (P<0.01). Moreover, with respect to the bone cement dosage, vertebral correction height, operation time, cumulative radiation dose, percolation rate, and volume of bone cement, the double-arm DSA-guided PKP treatment showed significantly better results than the C-arm-guided PKP treatment (P<0.01).

Conclusions

Our data revealed that double-arm DSA-guided PKP was more accurate in treatment of senile osteoporotic thoracolumbar vertebral compression fractures, producing excellent performance with more accurate intraoperative evaluation, shorter operative time, lower incidence of bone cement leakage, less intraoperative radiation dose, and higher safety, and thus, could be extensively applied to clinical surgery.

Utility of 'dual phase' cone beam computed tomography during radioembolisation in patients with hepatocellular carcinoma: what is really changing in flow dynamics before and after 90Y delivery?

Purpose

The aims of the study were: 1) to compare two phases of dual-phase cone beam computed tomography (DP-CBCT) achieved before and after Yttrium-90 (⁹⁰Y) administration and to evaluate additional benefits during radioembolisation (RE) procedures; and 2) to compare DP-CBCT with pre-procedure contrast enhanced cross-sectional images in terms of tumour detection.

Material and methods

Twenty-three hepatocellular carcinoma patients undergoing RE treatment were scanned with DP-CBCT consisting of early arterial (EA) and late arterial (LA) phases before and after ⁹⁰Y administration. The CT-like datasets were compared according to embolisation effect, enhancement patterns, lesion detectability, image quality, and artifacts by two interventional radiologists blinded to each other. The compatibility of the two radiologists was evaluated with kappa statistical analysis, and the difference between EA and LA phases was evaluated with marginal homogeneity test. Also, DP-CBCT images were compared with preprocedural cross-sectional images (CT/MRI).

Results

For 23 patients 92 data were acquired. Thirteen patients showed a decrease on post-embolisation images both visually and on Hounsfield unit (HU) measurements. No statistical difference was found for tumour detection between EA and LA phases (p = 1.0). Tumour enhancement was visually superior at LA phases whereas EA phases were better for arterial mapping for selective catheterisation. DP-CBCT images were not inferior to preprocedural cross-sectional imaging findings.

Conclusions

DP-CBCT is a promising tool for predicting tumour response to therapy and is not inferior to preprocedural cross-sectional imaging in terms of tumour detection. It allows better assessment during RE procedures because early phases provide good mapping for superselective catheterisation whereas late phases are better for visualisation of tumour enhancement.

Intrahepatic arterial localizer guided transjugular intrahepatic portosystemic shunt placement: Feasibility, efficacy, and technical success assessed by a case series-a STROBE- compliant article

Transjugular intra-hepatic portosystemic shunts (TIPS) had been considered a standard procedure in patients suffering from portal hypertension. The most challenging step in TIPS placement is blind puncture of the portal vein. We had established a localization method by introducing an Intra-Hepatic Arterial based puncture directing Localizer (IHAL) with the assistance of the enhanced computed tomography (CT) reconstruction. This study aimed to evaluate the feasibility, efficacy, and technical success of this method.From June 2018 to August 2018, 10 consecutive patients suffering from refractory ascites or esophageal gastric bleeding by liver cirrhosis were included in this retrospective study to evaluate feasibility, efficacy, and technical success of enhanced CT assisted IHAL-guided puncture of the portal vein. As a control, 10 patients receiving TIPS placement before Jun 2018 with cone beam CT (CBCT)-guided puncture were included to compare the reduction of portal-systemic pressure gradient (PSPG), portal entry time (PET), the number of puncture, dose area product (DAP) and contrast medium consumption.Technical success was 100% in the study group (IHAL-guided group) and in 90.0% of the control group (CBCT-guided group). Appropriate IHAL point could be achieved in all patients under the enhanced CT reconstruction assistance. The median number of punctures and DAP in IHAL group were significantly less than those in CBCT group. The reduction of PSPG, PET, and contrast medium consumption in IHAL group showed no significant differences than those in CBCT group.Enhanced CT reconstruction assisted IHAL-guided portal vein puncture is technically feasible and a reliable tool for TIPS placement resulting in a significant reduction of the number of punctures and DAP.

Radiation exposure of dogs and cats undergoing fluoroscopic procedures and for operators performing those procedures

OBJECTIVE

To evaluate radiation exposure of dogs and cats undergoing procedures requiring intraoperative fluoroscopy and for operators performing those procedures.

SAMPLE

360 fluoroscopic procedures performed at 2 academic institutions between 2012 and 2015.

PROCEDURES

Fluoroscopic procedures were classified as vascular, urinary, respiratory, cardiac, gastrointestinal, and orthopedic. Fluoroscopy operators were classified as interventional radiology-trained clinicians, orthopedic surgeons, soft tissue surgeons, internists, and cardiologists. Total radiation exposure in milligrays and total fluoroscopy time in minutes were obtained from dose reports for 4 C-arm units. Kruskal-Wallis equality of populations rank tests and Dunn pairwise comparisons were used to compare differences in time and exposure among procedures and operators.

RESULTS

Fluoroscopy time (median, 35.80 minutes; range, 0.60 to 84.70 minutes) was significantly greater and radiation exposure (median, 137.00 mGy; range, 3.00 to 617.51 mGy) was significantly higher for vascular procedures than for other procedures. Median total radiation exposure was significantly higher for procedures performed by interventional radiology-trained clinicians (16.10 mGy; range, 0.44 to 617.50 mGy), cardiologists (25.82 mGy; range, 0.33 to 287.45 mGy), and internists (25.24 mGy; range, 3.58 to 185.79 mGy).

CONCLUSIONS AND CLINICAL RELEVANCE

Vascular fluoroscopic procedures were associated with significantly longer fluoroscopy time and higher radiation exposure than were other evaluated fluoroscopic procedures. Future studies should focus on quantitative radiation monitoring for patients and operators, importance of operator training, intraoperative safety measures, and protocols for postoperative monitoring of patients.

A new imaging technology to reduce the radiation dose during uterine fibroid embolization

BACKGROUND

Uterine fibroid embolization (UFE) is a minimally invasive imaging-guided treatment using radiation exposure.

PURPOSE

To compare the patients' radiation exposure during UFE before and after introduction of a new X-ray imaging platform.

MATERIAL AND METHODS

Forty-one patients were enrolled in a prospective, comparative two-arm project before and after introduction of a new X-ray imaging platform with reduced dose settings, i.e. novel real-time image processing techniques (AlluraClarity). Demographic, pre-interventional imaging, and procedural data, including dose area product (DAP) and estimated organ dose on the ovaries and uterus, were recorded and angiographic quality of overall procedure was assessed.

RESULTS

There were no significant differences in demographic characteristics and preoperative fibroid and uterine volumes in the two groups. The new imaging platform led to a significant reduction in mean total DAP (102 vs. 438 Gy.cm²; P < 0.001), mean fluoroscopy DAP (32 vs. 138 Gy.cm²; P < 0.001), mean acquisition DAP (70 vs. 300 Gy.cm²; P < 0.001), and acquisition DAP estimated organ dose in ovaries (42 vs. 118 mGy; P < 0.001) and uterus (40 vs. 118 mGy, P < 0.001), without impairment of the procedure and angiographic image quality.

CONCLUSION

A substantial 77% reduction of DAP values and 64% and 66% reduction in organ dose on ovaries and uterus, respectively, was demonstrated with the new imaging platform, while maintaining optimal imaging quality and efficacy.

Radiation exposure during TACE procedures using additional cone-beam CT (CBCT) for guidance: safety and precautions

Background During transarterial chemoembolization (TACE), cone-beam computed tomography (CBCT) can be used for tumor and feeding vessel detection as well as postembolization CT imaging. However, there will be additional radiation exposure from CBCT. Purpose To evaluate the additional dose raised through CBCT-assisted guidance in comparison to TACE procedures guided with pulsed digital subtraction angiography (DSA) alone. Material and Methods In 70 of 140 consecutive patients undergoing TACE for liver cancer, CBCT was used to facilitate the TACE. Cumulative dose area product (DAP), cumulative kerma(air), DAP values of DSA, total and cine specific fluoroscopy times (FT) of 1375 DSA runs, and DAP of 91 CBCTs were recorded and analyzed using Spearman's correlation, Mann-Whitney U-test, and Kruskal-Wallis test. P values < 0.05 were considered significant. Results Additional CBCT increased DAP by 2% ( P = 0.737), kerma(air) by 24.6% ( P = 0.206), and FT by 0.02% ( P = 0.453). Subgroup analysis revealed that postembolization CBCT for detection of ethiodized oil deposits added more DAP to the procedure. Performing CBCT-assisted TACE, DSA until first CBCT contributed about 38% to the total DAP. Guidance CBCT acquisitions conduced to 6% of the procedure's DAP. Additional DSA for guidance after CBCT acquisition required approximately 46% of the mean DAP. The last DSA run for documentation purposes contributed about 10% of the DAP. Conclusion CBCT adds radiation exposure in TACE. However, the capability of CBCT to detect vessels and overlay in real-time during fluoroscopy facilitates TACE with resultant reduction of DAPs up to 46%.

Visibility of Hypovascularized Liver Tumors during Intra-Arterial Therapy Using Split-Bolus Single-Phase Cone Beam CT

PURPOSE

To validate a split-bolus contrast injection protocol for single-phase CBCT in terms of detectability of hypovascular liver tumors compared to digital subtraction angiography (DSA).

MATERIALS AND METHODS

In this retrospective, single-center study, 20 consecutive patients with in total 77 hypovascularized tumors referred for intra-arterial therapy received a split-bolus single-phase CBCT. Two readers rated the visibility of the target tumors scheduled for embolization in CBCT and DSA compared to the pre-interventional multiphasic CT or MRI used as reference on a 3-point scoring system (1 = optimal, 3 = not visible) and catheter-associated artifacts (1 = none, 3 = extended). SNR, CNR and contrast values were derived from 37 target tumors in CBCT and MRI. Statistical analysis included the kappa test to determine interrater reliability, the Friedman's test for the inter-modality comparison evaluating tumor visibility in DSA and CBCT as well as for quantitative assessment. Post hoc analysis included the Wilcoxon signed-rank test. p values < 0.05 were considered significant.

RESULTS

Ninety percentage of target tumors were rated as visible in CBCT and 37.5% in DSA (p < 0.001). 70.1% of pre-interventionally detected hypovascularized tumors were depicted with CBCT and 31.2% by DSA (p < 0.001). 7.8% of known tumors were outside the FOV. Quantitative assessment showed higher image contrasts in CBCT (1.91 ± 7.01) compared to hepatobiliary-phase MRI (0.29 ± 0.14, p = 0.003) and to portal-venous (p.v.) MRI (0.31 ± 0.13, p < 0.001), but higher CNR for MRI (1.18 ± 0.80; 13.92 ± 15.82; 13.79 ± 6.65).

CONCLUSION

In conclusion, the split-bolus single-phase CBCT detects significantly more hypovascularized liver tumors compared to DSA performed through the proper hepatic artery with high image contrasts.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Patient Radiation Dose Reduction Considerations in a Contemporary Interventional Radiology Suite

PURPOSE

We sought to evaluate patient radiation exposure during complex liver interventional procedures performed with newer angiography equipment.

MATERIALS AND METHODS

We conducted a retrospective study of transjugular intrahepatic portosystemic shunt (TIPS) creations and liver tumor embolizations performed in our new angiography suite (Discovery IGS740, GE Healthcare). T tests were used to compare air kerma-area product (P_KA) and reference plane air kerma (K_a,r) in the new room versus data from historical rooms and previous studies (including the RAD IR study). Results were expressed as medians [interquartile ranges (Q1, Q3)].

RESULTS

From February 2015 to June 2016, 134 complex liver interventional procedures were performed in the new room, including 14 TIPS creations, 60 hepatic tumor arterial embolizations (HAEs), 26 Y90 mappings (Y90m), and 34 Y90 radioembolizations (Y90). K_a,r (Gy) values were as follows: TIPS, 0.65 (0.24, 1.15); HAE, 0.89 (0.49, 1.49); Y90m, 0.54 (0.38, 0.94); Y90, 0.46 (0.21, 1.06). P_KA (Gy·cm²) values were as follows: TIPS, 148.2 (66.7, 326.5); HAE, 142.6 (88, 217.8); Y90m, 148.3 (98.2, 247); Y90, 90.8 (43.9, 161.5). K_a,r and P_KA were lower in the new room than in historical rooms [K_a,r and P_KA reductions: TIPS, 58 and 49%; HAE, 31 and 39%; Y90m, 58 and 52%; Y90, 49 and 56% (p < 0.05)] and versus the RAD IR study [K_a,r and P_KA reductions: TIPS, 64 and 43%; HAE, 26 and 40% (p < 0.05)].

CONCLUSIONS

Using the latest technology and image processing tools enables significant reduction in radiation exposure during complex liver interventional procedures.

Interventional Equipment and Radiation Safety

Interventional radiology in veterinary medicine was adapted from techniques developed in human medicine, and has a variety of applications to treat disease in multiple body systems. Fluoroscopy is required for almost all interventional procedures, requiring knowledge of proper safety techniques for working with ionizing radiation. There are a wide variety of catheters, wires, sheaths, stents, and embolics used in veterinary medicine. Familiarity with their indications and sizing compatibility is essential for procedural success.

Intraprocedural 3D perfusion measurement during chemoembolisation with doxorubicin-eluting beads in liver metastases of malignant melanoma

OBJECTIVES

To study feasibility and validity of a new software application for intraprocedural assessment of perfusion during chemoembolisation of melanoma metastases.

METHODOLOGY

In a prospective phase-II trial, ten melanoma patients with liver-only metastases underwent chemoembolisation with doxorubicin-eluting beads (DEBDOX-TACE). Tumour perfusion was evaluated immediately before and after treatment at cone beam computer tomography (CBCT) using a new software application. For control and comparison, patients underwent perfusion measurement via contrast-enhanced multidetector CT (MDCT) before and after treatment.

RESULTS

CBCT showed 94.7 % reduction in perfusion in metastases after DEBDOX-TACE, whereas MDCT showed 96.8 %. Reduction in perfusion after treatment was statistically significant (p < 0.01) for both methods. The additional time needed for data acquisition during treatment was 5 min per case or less; the post-processing data analysis was 10 min or less. Perfusion imaging was associated with additional contrast agent and patient exposure to radiation (dose-length product [DLP]): 18 ml and 394 mGy*cm in CBCT and 100 ml and 446 mGy*cm in MDCT, respectively.

CONCLUSIONS

Reduction in perfusion of melanoma metastases after DEBDOX-TACE can be reliably assessed during the intervention via perfusion software at CBCT. Data acquisition and analysis require additional time but can be easily performed during the treatment.

KEY POINTS

• Tumour perfusion of melanoma metastases can be assessed at cone beam CT. • The software shows a significant decrease of tumour perfusion after DEBDOX-TACE. • Data acquisition and analysis require an acceptable additional time during the procedure. • CBCT requires less radiation exposure and contrast for perfusion study than MSCT. • This software can monitor the course of DEBDOX-TACE in melanoma metastases.

Noise reduction angiographic imaging technology reduces radiation dose during bronchial artery embolization

PURPOSE

Comparison of radiation doses in patients undergoing angiographic bronchial artery embolization (BAE) before and after a noise reduction imaging technology upgrade.

METHODS

We performed a retrospective study of 70 patients undergoing BAE. Procedures were performed before (n=32) and after (n=38) the technology upgrade containing additional filters and improved image-processing. Cumulative air kerma (AK), cumulative dose area product (DAP), number of exposure frames, total fluoroscopy time and amount of contrast agent were recorded. Mean values were calculated and compared using two-tailed t-tests. DSA image quality was assessed independently by two blinded readers and compared using the Wilcoxon signed-rank test.

RESULTS

Using the new technology resulted in a significant reduction of 59% in DAP (149.2 (103.1-279.1) vs. 54.8 (38.2-100.7) Gy*cm², p<0.001) and a significant reduction of 60% for AK (1.3 (0.6-1.9) vs. 0.5 (0.3-0.9) Gy, p<0.001) in comparison to procedures before the upgrade. There was no significant difference between the number of exposure frames in both groups (251±181 vs. 254±133 frames, p=0.07), time of fluoroscopy (28.8 (18.5-50.4) vs. 28.1 (23.3-38.7) min, p=0.73), or the amount of contrast agent used (139.5±70.8 vs. 163.1±63.1ml, p=0.11). No significant difference regarding image quality could be detected (3 (2,3) vs. 3 (2-4), p=0.64).

CONCLUSIONS

The new angiographic noise reduction technology significantly decreases the radiation dose during bronchial artery embolization without compromising image quality or increasing time of fluoroscopy or contrast volume.

Characteristics of a New X-Ray Imaging System for Interventional Procedures: Improved Image Quality and Reduced Radiation Dose

Purpose

To compare image quality and radiation exposure between a new angiographic imaging system and the preceding generation system during uterine artery embolization (UAE).

Materials and Methods

In this retrospective, IRB-approved two-arm study, 54 patients with symptomatic uterine fibroids were treated with UAE on two different angiographic imaging systems. The new system includes optimized acquisition parameters and real-time image processing algorithms. Air kerma (AK), dose area product (DAP) and acquisition time for digital fluoroscopy (DF) and digital subtraction angiography (DSA) were recorded. Body mass index was noted as well. DF image quality was assessed objectively by image noise measurements. DSA image quality was rated by two blinded, independent readers on a four-rank scale. Statistical differences were assessed with unpaired t tests and Wilcoxon rank-sum tests.

Results

There was no significant difference between the patients treated on the new (n = 36) and the old system (n = 18) regarding age (p = 0.10), BMI (p = 0.18), DF time (p = 0.35) and DSA time (p = 0.17). The new system significantly reduced the cumulative AK and DAP by 64 and 72%, respectively (median 0.58 Gy and 145.9 Gy*cm² vs. 1.62 Gy and 526.8 Gy*cm², p < 0.01 for both). Specifically, DAP for DF and DSA decreased by 59% (75.3 vs. 181.9 Gy*cm², p < 0.01) and 78% (67.6 vs. 312.2 Gy*cm², p < 0.01), respectively. The new system achieved a significant decrease in DF image noise (p < 0.01) and a significantly better DSA image quality (p < 0.01).

Conclusions

The new angiographic imaging system significantly improved image quality and reduced radiation exposure during UAE procedures.

Electronic supplementary material

The online version of this article (doi:10.1007/s00270-017-1821-z) contains supplementary material, which is available to authorized users.

Impact of Allura Clarity Technology on Radiation Dose Exposure During Left Atrial Appendage Closure

BACKGROUND

To evaluate the impact of the Clarity IQ technology on reducing radiation risk in patients undergoing cardiac interventional radiology (IR) procedures.

MATERIAL/METHODS

Phantom studies were performed with two angiographic systems, FD10 Allura Xper and FD10 Allura Clarity. In the study, we performed left atrial appendage closure. Dosimetric measurements were performed with thermoluminescent dosimeters (TLD) placed inside a CIRS anthropomorphic phantom. Radiation risk was estimated based on the TLD readings and expressed as the dose absorbed by particular organs. The Mann-Whitney U test was carried out to test for significance of differences in the absorbed radiation doses between the techniques.

RESULTS

During left atrial appendage closure, the estimated dose absorbed by particular organs was lower in the case of the FD10 Allura Clarity system in comparison to the Allura Xper. In this procedure, dose reduction for particular organs ranged between 49-86%.

CONCLUSIONS

Application of the FD10 Allura Clarity system resulted in a significant dose reduction, thereby leading to a significant decrease in radiation risk for patients undergoing IR procedures.

Interventional Oncology in Hepatocellular Carcinoma: Progress Through Innovation

The clinical management of hepatocellular carcinoma has evolved greatly in the last decade mostly through recent technical innovations. In particular, the application of cutting-edge image guidance has led to minimally invasive solutions for complex clinical problems and rapid advances in the field of interventional oncology. Many image-guided therapies, such as transarterial chemoembolization and radiofrequency ablation, have meanwhile been fully integrated into interdisciplinary clinical practice, whereas others are currently being investigated. This review summarizes and evaluates the most relevant completed and ongoing clinical trials, provides a synopsis of recent innovations in the field of intraprocedural imaging and tumor response assessment, and offers an outlook on new technologies, such as radiopaque embolic materials. In addition, combination therapies consisting of locoregional therapies and systemic molecular targeted agents (e.g., sorafenib) remain of major interest to the field and are also discussed. Finally, we address the many substantial advances in immune response pathways that have been related to the systemic effects of locoregional therapies. Knowledge of these new developments is crucial as they continue to shape the future of cancer treatment, further establishing interventional oncology along with surgical, medical, and radiation oncology as the fourth pillar of cancer care.

The Effect of a New Angiographic Imaging Technology on Radiation Dose in Visceral Embolization Procedures

PURPOSE

To evaluate the impact of a new angiographic imaging technology on radiation dose during visceral embolization procedures involving both fluoroscopy and digital subtraction angiography.

MATERIAL AND METHODS

A retrospective analysis from a single-center consecutive series of patients was performed comparing 2 angiographic imaging systems. The AlluraClarity (CIQ; Philips Healthcare, Best, the Netherlands) was used in 100 patients (n = 59 male, mean age: 70.6 years) from July 2013 to April 2014 and compared to the former AlluraXper (AX) technology used in 139 patients (n = 71 male, mean age: 70.1 years) from May 2011 to June 2013. Patients were categorized according to body mass index (BMI [kg/m²])-group 1: BMI <25, group 2: BMI ≥25 and <30, and group 3: BMI ≥30. Fluoroscopy time, the total dose of iodinated contrast administered, and procedural AirKerma (Ka, r [mGy]) were obtained.

RESULTS

Mean BMI was 26.4 ± 5.0 kg/m² in the CIQ and 26.4 ± 7.1 kg/m² in the AX group ( P = .93). Fluoroscopy time and the amount of contrast media were equally distributed. Ka, r was 1342.9 mGy versus 2214.8 mGy ( P < .001, t test) when comparing CIQ to AX. Comparing CIQ to AX, BMI subgroup analysis revealed a mean Ka, r of 970.1 to 1586.1 mGy ( P = .003, t test), 1484.7 to 2170.1 mGy ( P = .02, t test), and 1848.8 to 3348.9 mGy ( P = .001, t test) in BMI groups 1, 2, and 3, respectively.

CONCLUSION

The CIQ technology significantly reduced mean radiation dose by 39.4% for visceral embolization procedures when compared to fluoroscopy time and contrast media dose. This dose relationship was consistent across all BMI groups.

New concepts in embolotherapy of HCC

Hepatocellular carcinoma (HCC) is the second most common cause of cancer-related deaths worldwide with rapidly growing incidence rates in the USA and Europe. Despite improving surveillance programs, most patients are diagnosed at intermediate to advanced stages and are no longer amenable to curative therapies, such as ablation, surgical resection and liver transplantation. For such patients, catheter-based image-guided embolotherapies such as transarterial chemoembolization (TACE) represent the standard of care and mainstay therapy, as recommended and endorsed by a variety of national guidelines and staging systems. The main benefit of these therapies is explained by the preferentially arterial blood supply of liver tumors, which allows to deliver the anticancer therapy directly to the tumor-feeding artery while sparing the healthy hepatic tissue mainly supplied by the portal vein. The tool box of an interventional oncologist contains several different variants of transarterial treatment modalities. Ever since the first TACE more than 30 years ago, these techniques have been progressively refined, both with respect to drug delivery materials and with respect to angiographic micro-catheter and image-guidance technology, thus substantially improving therapeutic outcomes of HCC. This review will summarize the fundamental principles, technical and clinical data on the application of different embolotherapies, such as bland transarterial embolization, Lipiodol-based conventional transarterial chemoembolization as well as TACE with drug-eluting beads (DEB-TACE). Clinical data on ⁹⁰Yttrium radioembolization as an emerging alternative, mostly applied for niche indications such as HCC with portal vein invasion, will be discussed. Furthermore, we will summarize the principle of HCC staging, patient allocation and response assessment in the setting of HCC embolotherapy. In addition, we will evaluate the role of cone-beam computed tomography as a novel intra-procedural image-guidance technology. Finally, this review will touch on new technical developments such as radiopaque, imageable DEBs and the rationale and role of combined systemic and locoregional therapies, mostly in combination with Sorafenib.

Radiation dose reduction during transjugular intrahepatic portosystemic shunt implantation using a new imaging technology

OBJECTIVE

To compare patient radiation dose in patients undergoing transjugular intrahepatic portosystemic shunt (TIPS) implantation before and after an imaging-processing technology upgrade.

METHODS

In our retrospective single-center-study, cumulative air kerma (AK), cumulative dose area product (DAP), total fluoroscopy time and contrast agent were collected from an age- and BMI-matched collective of 108 patients undergoing TIPS implantation. 54 procedures were performed before and 54 after the technology upgrade. Mean values were calculated and compared using two-tailed t-tests. Two blinded, independent readers assessed DSA image quality using a four-rank likert scale and the Wilcoxcon test.

RESULTS

The new technology demonstrated a significant reduction of 57% of mean DAP (402.8 vs. 173.3Gycm², p<0.001) and a significant reduction of 58% of mean AK (1.7 vs. 0.7Gy, p<0.001) compared to the precursor technology. Time of fluoroscopy (26.4 vs. 27.8min, p=0.45) and amount of contrast agent (109.4 vs. 114.9ml, p=0.62) did not differ significantly between the two groups. The DSA image quality of the new technology was not inferior (2.66 vs. 2.77, p=0.56).

CONCLUSIONS

In our study the new imaging technology halved radiation dose in patients undergoing TIPS maintaining sufficient image quality without a significant increase in radiation time or contrast consumption.

Improved Visibility of Metastatic Disease in the Liver During Intra-Arterial Therapy Using Delayed Arterial Phase Cone-Beam CT

Purpose

To compare the visibility of liver metastases on dual-phase cone-beam CT (DP-CBCT) and digital subtraction angiography (DSA), with reference to preinterventional contrast-enhanced magnetic resonance imaging (CE-MRI) of the liver.

Methods

This IRB-approved, retrospective study included 28 patients with neuroendocrine (NELM), colorectal (CRCLM), or sarcoma (SLM) liver metastases who underwent DP-CBCT during intra-arterial therapy (IAT) between 01/2010 and 10/2014. DP-CBCT was acquired after a single contrast agent injection in the tumor-feeding arteries at early and delayed arterial phases (EAP and DAP). The visibility of each lesion was graded by two radiologists in consensus on a three-rank scale (complete, partial, none) on DP-CBCT and DSA images using CE-MRI as reference.

Results

47 NELM, 43 CRCLM, and 16 SLM were included. On DSA 85.1, 44.1, and 37.5 % of NELM, CRCLM, and SLM, were at least partially depicted, respectively. EAP-CBCT yielded significantly higher sensitivities of 88.3 and 87.5 % for CRCLM and SLM, respectively (p < 0.01), but not for NELM (89.4 %; p = 1.0). On DAP-CBCT all NELM, CRCLM, and SLM were visible (p < 0.001). Complete depiction was achieved on DSA for 59.6, 16.3, and 18.8 % of NELM, CRCLM, and SLM, respectively. The complete depiction rate on EAP-CBCT was significantly higher for CRCLM (46.5 %; p < 0.001), lower for NELM (40.4 %; p = 0.592), and similar for SLM (25 %, p = 0.399). On DAP-CBCT however, the highest rates of complete depiction were found—NELM (97.8 %; p = 0.008), CRCLM (95.3 %; p = 0.008), and SLM (100 %; p < 0.001).

Conclusion

DAP-CBCT substantially improved the visibility of liver metastases during IAT. Future studies need to evaluate the clinical impact.

Three-dimensional C-arm CT-guided transjugular intrahepatic portosystemic shunt placement: Feasibility, technical success and procedural time

OBJECTIVES

Establishment of transjugular intrahepatic portosystemic shunts (TIPS) constitutes a standard procedure in patients suffering from portal hypertension. The most difficult step in TIPS placement is blind puncture of the portal vein. This study aimed to evaluate three-dimensional mapping of portal vein branches and targeted puncture of the portal vein.

METHODS

Twelve consecutive patients suffering from refractory ascites by liver cirrhosis were included in this retrospective study to evaluate feasibility, technical success and procedural time of C-arm CT-targeted puncture of the portal vein. As a control, 22 patients receiving TIPS placement with fluoroscopy-guided blind puncture were included to compare procedural time.

RESULTS

Technical success could be obtained in 100 % of the study group (targeted puncture) and in 95.5 % of the control group (blind puncture). Appropriate, three-dimensional C-arm CT-guided mapping of the portal vein branches could be achieved in all patients. The median number of punctures in the C-arm CT-guided study group was 2 ± 1.3 punctures. Procedural time was significantly lower in the study group (14.8 ± 8.2 min) compared to the control group (32.6 ± 22.7 min) (p = 0.02).

CONCLUSIONS

C-arm CT-guided portal vein mapping is technically feasible and a promising tool for TIPS placement resulting in a significant reduction of procedural time.

KEY POINTS

• C-arm CT-mapping of the portal vein for 3D TIPS guidance is feasible. • Targeted punctures of the portal vein by C-arm CT reduce procedural time. • A decreased number of punctures could improve patient safety.

Reducing Patient Radiation Dose With Image Noise Reduction Technology in Transcatheter Aortic Valve Procedures

X-ray radiation exposure is of great concern for patients undergoing structural heart interventions. In addition, a larger group of medical staff is required and exposed to radiation compared with percutaneous coronary interventions. This study aimed at quantifying radiation dose reduction with implementation of specific image noise reduction technology (NRT) in transcatheter aortic valve implantation (TAVI) procedures. We retrospectively analyzed 104 consecutive patients with TAVI procedures, 52 patients before and 52 after optimization of x-ray radiation chain, and implementation of NRT. Patients with 1-step TAVI and complex coronary intervention, or complex TAVI procedures, were excluded. Before the procedure, all patients received a multislice computed tomography scan, which was used to size aortic annulus, select the optimal implantation plane, valve type and size, and guide valve implantation using a software tool. Air kerma and kerma-area product were compared in both groups to determine patient radiation dose reduction. Baseline parameters, co-morbidity, or procedural data were comparable between groups. Mean kerma-area product was significantly lower (p <0.001) in the NRT group compared with the standard group (60 ± 39 vs 203 ± 106 Gy × cm(2), p <0.001), which corresponds to a reduction of 70%. Mean air kerma was reduced by 64% (494 ± 360 vs 1,355 ± 657 mGy, p <0.001). In conclusion, using optimized x-ray chain combined with specific image noise reduction technology has the potential to significantly reduce by 2/3 radiation dose in standard TAVI procedures without worsening image quality or prolonging procedure time.

Feasibility of a Modified Cone-Beam CT Rotation Trajectory to Improve Liver Periphery Visualization during Transarterial Chemoembolization

PURPOSE

To compare liver coverage and tumor detectability by using preprocedural magnetic resonance (MR) images as a reference, as well as radiation exposure of cone-beam computed tomography (CT) with different rotational trajectories.

MATERIALS AND METHODS

Fifteen patients (nine men and six women; mean age ± standard deviation, 65 years ± 5) with primary or secondary liver cancer were retrospectively included in this institutional review board-approved study. A modified cone-beam CT protocol was used in which the C-arm rotates from +55° to -185° (open arc cone-beam CT) instead of -120° to +120° (closed arc cone-beam CT). Each patient underwent two sessions of transarterial chemoembolization between February 2013 and March 2014 with closed arc and open arc cone-beam CT (during the first and second transarterial chemoembolization sessions, respectively, as part of the institutional transarterial chemoembolization protocol). For each cone-beam CT examination, liver volume and tumor detectability were assessed by using MR images as the reference. Radiation exposure was compared by means of a phantom study. For statistical analysis, paired t tests and a Wilcoxon signed rank test were performed.

RESULTS

Mean liver volume imaged was 1695 cm(3) ± 542 and 1857 cm(3) ± 571 at closed arc and open arc cone-beam CT, respectively. The coverage of open arc cone-beam CT was significantly higher compared with closed arc cone-beam CT (97% vs 86% of the MR imaging liver volume, P = .002). In eight patients (53%), tumors were partially or completely outside the closed arc cone-beam CT field of view. All tumors were within the open arc cone-beam CT field of view. The open arc cone-beam CT radiation exposure by means of weighted CT index was slightly lower compared with that of closed arc cone-beam CT (-5.1%).

CONCLUSION

Open arc cone-beam CT allowed for a significantly improved intraprocedural depiction of peripheral hepatic tumors while achieving a slight radiation exposure reduction.