Characterization of Liver Metastases During Catheter-Directed Liver Interventions: A Comparison between Dual Phase Cone-Beam Computed Tomography and Conventional Contrast-Enhanced Computed Tomography.

OBJECTIVES: To compare the diagnostic performance of intra-arterial dual phase cone-beam computed tomography (DP-CBCT) with contrast-enhanced computed tomography (CE-CT) when characterizing tumor burden in patients with metastatic liver cancer. MATERIALS AND METHODS: This retrospective study included 29 patients with colorectal (n =10), breast (n = 9) and neuroendocrine (n = 10) liver metastases, referred for catheter-directed treatment. Tumor type, number, maximum size, and appearance were assessed. Paired-sample t-tests compared image quality, tumor numbers, and diameters between imaging modalities. RESULTS: Image quality was not different between DP-CBCT and CE-CT (p = 0.9). In 18 patients (62%) DP-CBCT and CE-CT showed diffuse, uncountable metastases in the liver. Of the remaining 11 patients, DP-CBCT identified two patients with diffuse tumors that appeared as a sum of 17 distinct metastases on CE-CT. In the remaining nine patients a total of 102 metastases were found using both DP-CBCT and CE-CT. Tumor detection accuracy was 98% in DP-CBCT and 67% in CE-CT (p = 0.025). Metastases were larger in diameter on DP-CBCT: colorectal: 57 +/- 9.5 mm versus 43 +/- 8.3 mm (p = 0.02); breast: 57 +/- 10 mm versus 43 +/- 8.5 mm (p = 0.03) and neuroendocrine: 56 +/- 6.3 mm versus 51 +/- 5.8 mm (p = 0.01). Rim enhancement appeared in 100% of patients with colorectal and 89% of patients with breast metastases on DP-CBCT, but was variable on CE-CT. Neuroendocrine tumors had variable rim enhancement within the same patient and across imaging modalities. CONCLUSIONS: DP-CBCT of the liver may demonstrate larger metastatic tumor burden and lesion size with a variable contrast enhancement compared to CE-CT.

Feasibility of Yttrium-90 Radioembolization Dose Calculation Utilizing Intra-procedural Open Trajectory Cone Beam CT.

PURPOSE: Dose calculation for transarterial radioembolization (TARE) with glass yttrium-90 (Y90) labeled microspheres is based on liver lobe and tumor volumes, currently measured from preprocedural MRI or CT. The variable time between MRI and radioembolization may not account for relevant tumor progression. Advances in cone beam computed tomography (CBCT) allow for intra-procedural assessment of these volumes that avoids this factor. Liver lobe and hepatocellular carcinoma tumor volume measurements and dose calculations using intra-procedural CBCT were compared to those using preprocedural MRI in order to determine feasibility. METHODS: Retrospective analysis was performed in 20 patients with proven hepatocellular carcinoma (HCC) who underwent planning angiography with open trajectory CBCT acquisitions prior to radioembolization, and an MRI performed within 6 weeks prior to treatment planning. Liver lobe and tumor burden volumes were measured based on CBCT using embolization planning and guidance software and measured on preprocedural MRI using standard volume analysis software. Y90 doses were subsequently calculated using each measured volume. Comparisons of volume measurements and calculated Y90 doses between the two modalities were evaluated for significance using paired t tests. RESULTS: All target liver lobes and all tumors were completely depicted on CBCT. Mean liver lobe and tumor burden volumes measured on intra-procedural CBCT and preprocedural MRI showed no significant difference (p = 0.71). Mean calculated Y90 dose based on each modality showed no significant difference (p = 0.18). CONCLUSIONS: Lobar and tumor volume measurement with CBCT is a reliable alternative to measurement with preprocedural MRI. Utilization of CBCT 3D segmentation software during planning angiography may be useful to provide up-to-date volume measurements and dose calculations prior to radioembolization.

Using the Hybrid Operating Room in Thoracic Surgery: A Paradigm Shift.

We describe the integration of the hybrid operation room cone-beam computed tomography (CT) scan technology into the practice of general thoracic surgery. The combination of the following three techniques: (1) cone-beam CT scan augmented navigational bronchoscopy, (2) cone-beam CT-guided percutaneous biopsy and/or fiducial placement, and (3) fiducial or image-guided video-assisted thoracic surgery resection, into a single-stage, single-provider procedure allows for diagnosis and treatment in one setting. Rapid on-site evaluation of cytological or pathology specimens is key to this "all-in-one" approach. The time from diagnosis to curative treatment can significantly be reduced using the hybrid operation room technology, leading to decreased upstaging, increased survival and facilitating the otherwise difficult intraoperative detection and resection of small and deeper lesions. Not only does this benefit the overall thoracic healthcare of the community but also provides a cost-effective paradigm for the institution.

Distribution and Detection of Radiopaque Beads after Hepatic Transarterial Embolization in Swine: Cone-Beam CT versus MicroCT.

PURPOSE: To determine the true distribution of radiopaque beads (ROBs) after hepatic embolization in swine as imaged by micro-computed tomography (microCT) compared with in vivo cone-beam computerized tomography (CT) imaged at different kVp settings. MATERIALS AND METHODS: Swine (n = 3) underwent hepatic transarterial embolization (n = 6) with the use of 70-150-µm ROBs under fluoroscopic guidance. After stasis, in vivo cone-beam CT was performed at 120, 100, and 80 kVp. The animal was euthanized, the liver resected, and microCT with 17 µm resolution performed on embolized tissue samples. The resulting cone-beam CT and microCT data were segmented and registered. Total vessel length, minimum volume-enclosing ellipsoid (MVEE), and number of independent volumes were measured. Maximum-intensity projections (MIPs) were generated for each cone-beam CT. RESULTS: Metrics for all cone-beam CT segmentations differed significantly from microCT segmentations. Segmentations at 80 kVp presented significantly greater vessel length, MVEE, and number of independent volumes compared with 100 kVp and 120 kVp. In addition, 100 kVp segmentations presented significantly greater vessel length than 120 kVp. MIPs presented greater visualization than cone-beam CT segmentations and improved as kVp decreased. CONCLUSIONS: The full ROB distribution was more extensive than was apparent on cone-beam CT. Quantitative measures of embolic distribution demonstrated significantly better correlation with microCT with decreasing kVp. Similarly, qualitative analysis of MIPs showed improved visualization of beads with decreasing kVp. These findings demonstrate the clinical value of 80 kVp and 100 kVp protocols in the imaging of radiopaque embolizations compared with 120 kVp. However, considerations on X-ray penetration and dose may favor use of 100 kVp imaging over 80 kVp.

Sensitivity and Reproducibility of Automated Feeding Artery Detection Software during Transarterial Chemoembolization of Hepatocellular Carcinoma.

PURPOSE: To evaluate the performance of automated feeder detection (AFD) software (EmboGuide; Philips Healthcare, Best, The Netherlands) on hepatocellular carcinoma (HCC) tumors during transarterial chemoembolization. MATERIALS AND METHODS: Forty-four first-time transarterial chemoembolization patients (37 men; mean age, 62 ± 11 years) were enrolled between May 2012 and July 2013. A total of 86 HCC lesions were treated (2.0 ± 1.4 lesions per patient; 27.6 ± 15.9 mm maximum diameter). One hundred forty-seven feeding arteries were found with digital subtraction angiography (DSA), cone-beam computed tomography (CT), and AFD software with the option of manual adjustment (MA). Three independent interventional radiologists analyzed the cone-beam CT images retrospectively with and without AFD and MA. Compared with the number of treated vessels, the number of true positives, false positives, false negatives, sensitivity, and interreader agreement were determined using clustered binary data analysis. RESULTS: Cone-beam CT enabled detection of 100 ± 3.5 feeding arteries (70% sensitivity) with 68.6% agreement among readers. AFD software significantly improved detection to 127±0.6 feeding arteries (86% sensitivity, P = .008) with 99.7% reader agreement and reduced the number of false negatives from an average of 47 ± 3.5 to 20 ± 0.6 (P = .008). MA of the AFD results produced similar feeding artery detection rates (127 ± 5.1, 86% sensitivity, P = .8), with lower interreader agreement (91.6%) and slightly fewer false positives (16 ± 0.0 to 14 ± 2.5, P = .4). CONCLUSIONS: AFD software significantly improved feeding artery detection rates during transarterial chemoembolization of HCC lesions with better user reproducibility compared with cone-beam CT alone. In conjunction with DSA, AFD enables maximum feeding artery detection in this setting.

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.

Accuracy of a Cone-Beam CT Virtual Parenchymal Perfusion Algorithm for Liver Cancer Targeting during Intra-arterial Therapy.

PURPOSE: To evaluate accuracy of virtual parenchymal perfusion (VPP) algorithm developed for targeting liver cancer during intra-arterial therapy (IAT) using cone-beam CT guidance. MATERIALS AND METHODS: VPP was retrospectively applied to 15 patients who underwent IAT for liver cancer. Virtual territory (VT) was estimated after positioning a virtual injection point on nonselective dual-phase (DP) cone-beam CT images acquired during hepatic arteriography at the same position chosen for selective treatment. Targeted territory (TT) was used as the gold standard and was defined by parenchymal phase enhancement of selective DP cone-beam CT performed before treatment start. Qualitative evaluation of anatomic conformity between VT and TT was performed using a 3-rank scale (poor, acceptable, excellent) by 3 double-blinded readers. VT and TT were also quantitatively compared using spatial overlap-based (Dice similarity coefficient [DSC], sensitivity, and positive predictive value), distance-based (mean surface distance [MSD]), and volume-based (absolute volume error and correlation between pairwise volumes) metrics. Interreader agreement was evaluated for the 2 evaluation methods. RESULTS: Eighteen DP cone-beam CT scans were performed. Qualitative evaluation showed excellent overlap between VT and TT in 88.9%-94.4%, depending on the readers. DSC was 0.78 ± 0.1, sensitivity was 80%, positive predictive value was 83%, and MSD was 5.1 mm ± 2.4. Absolute volume error was 15%, and R2 Pearson correlation factor was 0.99. Interreader agreement was good for both qualitative and quantitative evaluations. CONCLUSIONS: VPP algorithm is accurate and reliable in identification of liver arterial territories during IAT using cone-beam CT guidance.

Clinical impact of cone beam computed tomography on iterative treatment planning during ultrasound-guided percutaneous ablation of liver malignancies.

A standardized cone beam computed tomography (CBCT) protocol may impact optimal ablation probe(s) positioning during ultrasound-guided microwave ablation (MWA). To evaluate this hypothesis, 15 patients underwent ultrasound-guided percutaneous MWA of 15 liver lesions (10 hepatocellular carcinomas, 5 metastasis ranging 11-41 mm) with the ultrasound guidance assisted by a dedicated CBCT protocol. Pre-procedural enhanced CBCT (ceCBCT) was performed after intravenous contrast administration to visualize the lesion and determine the optimal approach using CBCT-based ablation planning software. MW antennas were positioned under ultrasound guidance, and non-enhanced CBCT was performed after deployment and fused with pre-procedural ceCBCT to assess tumor targeting and modify subsequent steps of the procedure. CBCT lesion detection accuracy and number of needle repositioning on the basis of CBCT information were recorded. Clinical success was measured on 1-month follow-up contrast-enhanced CT. The target lesion was detected on ceCBCT in 13 out of 15 patients (87%). The undetected lesions were only visible on diagnostic contrast-enhanced magnetic resonance imaging, which was then fused to the CBCT and fluoroscopy to facilitate targeting. MW antennas were repositioned on the basis of CBCT in 11 lesions (73%). Clinical success was achieved in 14/15 ablations (93%) with a mean follow-up of X months. The only case of local recurrence was expected, as the intent was tumor debulking. CBCT imaging during ultrasound-guided liver ablation is feasible and leads to ablation device repositioning in the majority of cases.

Characterization of a novel intrinsically radiopaque Drug-eluting Bead for image-guided therapy: DC Bead LUMI™.

We have developed a straightforward and efficient method of introducing radiopacity into Polyvinyl alcohol (PVA)-2-Acrylamido-2-methylpropane sulfonic acid (AMPS) hydrogel beads (DC Bead™) that are currently used in the clinic to treat liver malignancies. Coupling of 2,3,5-triiodobenzaldehyde to the PVA backbone of pre-formed beads yields a uniformly distributed level of iodine attached throughout the bead structure (~150mg/mL) which is sufficient to be imaged under standard fluoroscopy and computed tomography (CT) imaging modalities used in treatment procedures (DC Bead LUMI™). Despite the chemical modification increasing the density of the beads to ~1.3g/cm3 and the compressive modulus by two orders of magnitude, they remain easily suspended, handled and administered through standard microcatheters. As the core chemistry of DC Bead LUMI™ is the same as DC Bead™, it interacts with drugs using ion-exchange between sulfonic acid groups on the polymer and the positively charged amine groups of the drugs. Both doxorubicin (Dox) and irinotecan (Iri) elution kinetics for all bead sizes evaluated were within the parameters already investigated within the clinic for DC Bead™. Drug loading did not affect the radiopacity and there was a direct relationship between bead attenuation and Dox concentration. The ability (Dox)-loaded DC Bead LUMI™ to be visualized in vivo was demonstrated by the administration of into hepatic arteries of a VX2 tumor-bearing rabbit under fluoroscopy, followed by subsequent CT imaging.

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.

Prospective Randomized Trial for Image-Guided Biopsy Using Cone-Beam CT Navigation Compared with Conventional CT.

PURPOSE: To compare cone-beam computed tomography (CT) navigation vs conventional CT image guidance during biopsies. MATERIALS AND METHODS: Patients scheduled for image-guided biopsies were prospectively and randomly assigned to conventional CT guidance vs cone-beam CT navigation. Radiation dose, accuracy of final needle position, rate of histopathologic diagnosis, and number of needle repositions to reach the target (defined as pullback to adjust position) were compared. RESULTS: A total of 58 patients (mean age, 57 y; 62.1% men) were randomized: 29 patients underwent 33 biopsies with CT guidance and 29 patients with 33 lesions underwent biopsy with cone-beam CT navigation. The average body mass index (BMI) was similar between groups, at 28.8 kg/m(2) ± 6.55 (P = .18). There was no difference between groups in terms of patient and lesion characteristics (eg, size, depth). The average lesion size was 29.1 ± 12.7mm for CT group vs 32.1mm ±16.8mm for cone-beam CT group (P < 0.59). Location of lesions was equally divided between the 2 groups, 20 lung lesions, 18 renal lesions and 20 other abdominal lesions. Mean number of needle repositions in the cone-beam CT group was 0.3 ± 0.5, compared with 1.9 ± 2.3 with conventional CT (P < .001). The average skin entry dose was 29% lower with cone-beam CT than with conventional CT (P < .04 accounting for BMI). The average estimated effective dose for the planning scan from phantom data was 49% lower with cone-beam CT vs conventional CT (P = .018). Accuracy, defined as the difference between planned and final needle positions, was 4.9 mm ± 4.1 for the cone-beam CT group, compared with 12.2 mm ± 8.1 for conventional CT (P < .001). Histopathologic diagnosis rates were similar between groups, at 90.9% for conventional CT and 93.9% for cone-beam CT (P = .67). CONCLUSIONS: Cone-beam CT navigation for biopsies improved targeting accuracy with fewer needle repositions, lower skin entry dose, and lower effective dose for planning scan, and a comparable histopathologic diagnosis rate.

First Human Experience with Directly Image-able Iodinated Embolization Microbeads.

PURPOSE: To describe first clinical experience with a directly image-able, inherently radio-opaque microspherical embolic agent for transarterial embolization of liver tumors. METHODOLOGY: LC Bead LUMI™ is a new product based upon sulfonate-modified polyvinyl alcohol hydrogel microbeads with covalently bound iodine (~260 mg I/ml). 70-150 µ LC Bead LUMI™ iodinated microbeads were injected selectively via a 2.8 Fr microcatheter to near complete flow stasis into hepatic arteries in three patients with hepatocellular carcinoma, carcinoid, or neuroendocrine tumor. A custom imaging platform tuned for LC LUMI™ microbead conspicuity using a cone beam CT (CBCT)/angiographic C-arm system (Allura Clarity FD20, Philips) was used along with CBCT embolization treatment planning software (EmboGuide, Philips). RESULTS: LC Bead LUMI™ image-able microbeads were easily delivered and monitored during the procedure using fluoroscopy, single-shot radiography (SSD), digital subtraction angiography (DSA), dual-phase enhanced and unenhanced CBCT, and unenhanced conventional CT obtained 48 h after the procedure. Intra-procedural imaging demonstrated tumor at risk for potential under-treatment, defined as paucity of image-able microbeads within a portion of the tumor which was confirmed at 48 h CT imaging. Fusion of pre- and post-embolization CBCT identified vessels without beads that corresponded to enhancing tumor tissue in the same location on follow-up imaging (48 h post). CONCLUSION: LC Bead LUMI™ image-able microbeads provide real-time feedback and geographic localization of treatment in real time during treatment. The distribution and density of image-able beads within a tumor need further evaluation as an additional endpoint for embolization.

Evaluation of tablet ultrasound for routine abdominal interventional procedures.

AIM: The aim of the study was to establish if a novel tablet ultrasound (US) may replace a high-end US machine during routine interventional radiology activities. MATERIALS AND METHODS: Thirty consecutive patients were evaluated by two operators comparing the performance of the new US tablet system (VISIQ, Philips Healthcare) against a high-end US system (iU22, Philips Healthcare) using a curved probe (C5-2). A structured questionnaire was used to rank on a 4-point scale the ability of each system to locate a target as detected by previous examinations and visualize needles and path during an interventional procedure. Necessity for conversion from the tablet US to the high-end US system was registered; body mass index (BMI) was annotated for each patient. RESULTS: Agreement between the operators was found for every patient. Mean patient BMI was 25 (range 17-34). Image quality of the tablet US was considered insufficient in 1 case to visualize the target and in another case to visualize the needle. Mean target image quality was superior with the high-end US system, while needle visibility scored higher with the tablet US. Conversion to the high-end system was registered in 40 % of cases: in most cases (66.6 %) the decision was due to the absence of a dedicated needle guide for the tablet US. CONCLUSIONS: The novel tablet US was found to provide sufficient image quality for the majority of routine interventional procedures. Dedicated accessories and additional experience with this new generation US device may be needed to replace bulky high-end US systems.

A Novel Inherently Radiopaque Bead for Transarterial Embolization to Treat Liver Cancer - A Pre-clinical Study.

PURPOSE: Embolotherapy using microshperes is currently performed with soluble contrast to aid in visualization. However, administered payload visibility dimishes soon after delivery due to soluble contrast washout, leaving the radiolucent bead's location unknown. The objective of our study was to characterize inherently radiopaque beads (RO Beads) in terms of physicomechanical properties, deliverability and imaging visibility in a rabbit VX2 liver tumor model. MATERIALS AND METHODS: RO Beads, which are based on LC Bead® platform, were compared to LC Bead. Bead size (light microscopy), equilibrium water content (EWC), density, X-ray attenuation and iodine distribution (micro-CT), suspension (settling times), deliverability and in vitro penetration were investigated. Fifteen rabbits were embolized with either LC Bead or RO Beads + soluble contrast (iodixanol-320), or RO Beads+dextrose. Appearance was evaluated with fluoroscopy, X-ray single shot, cone-beam CT (CBCT). RESULTS: Both bead types had a similar size distribution. RO Beads had lower EWC (60-72%) and higher density (1.21-1.36 g/cc) with a homogeneous iodine distribution within the bead's interior. RO Beads suspension time was shorter than LC Bead, with durable suspension (>5 min) in 100% iodixanol. RO Beads ≤300 µm were deliverable through a 2.3-Fr microcatheter. Both bead types showed similar penetration. Soluble contrast could identify target and non-target embolization on fluoroscopy during administration. However, the imaging appearance vanished quickly for LC Bead as contrast washed-out. RO Beads+contrast significantly increased visibility on X-ray single shot compared to LC Bead+contrast in target and non-target arteries (P=0.0043). Similarly, RO beads demonstrated better visibility on CBCT in target arteries (P=0.0238) with a trend in non-target arteries (P=0.0519). RO Beads+dextrose were not sufficiently visible to monitor embolization using fluoroscopy. CONCLUSION: RO Beads provide better conspicuity to determine target and non-target embolization compared to LC Bead which may improve intra-procedural monitoring and post-procedural evaluation of transarterial embolization.

Fusion of CT Angiography or MR Angiography with Unenhanced CBCT and Fluoroscopy Guidance in Endovascular Treatments of Aorto-Iliac Steno-Occlusion: Technical Note on a Preliminary Experience.

AIM: To evaluate the feasibility of image fusion (IF) of pre-procedural arterial-phase CT angiography or MR angiography with intra-procedural fluoroscopy for road-mapping in endovascular treatment of aorto-iliac steno-occlusive disease. MATERIALS AND METHODS: Between September and November, 2014, we prospectively evaluated 5 patients with chronic aorto-iliac steno-occlusive disease, who underwent endovascular treatment in the angiography suite. Fusion image road-mapping was performed using angiographic phase CT images or MR images acquired before and intra-procedural unenhanced cone-beam CT. Radiation dose of the procedure, volume of intra-procedural iodinated contrast medium, fluoroscopy time, and overall procedural time were recorded. Reasons for potential fusion imaging inaccuracies were also evaluated. RESULTS: Image co-registration and fusion guidance were feasible in all procedures. Mean radiation dose of the procedure was 60.21 Gycm2 (range 55.02-63.75 Gycm2). The mean total procedure time was 32.2 min (range 27-38 min). The mean fluoroscopy time was 12 min and 3 s. The mean procedural iodinated contrast material dose was 24 mL (range 20-40 mL). CONCLUSIONS: IF gives Interventional Radiologists the opportunity to use new technologies in order to improve outcomes with a significant reduction of contrast media administration.

Unenhanced Cone Beam Computed Tomography and Fusion Imaging in Direct Percutaneous Sac Injection for Treatment of Type II Endoleak: Technical Note.

AIM: To evaluate safety, feasibility, technical success, and clinical success of direct percutaneous sac injection (DPSI) for the treatment of type II endoleaks (T2EL) using anatomical landmarks on cone beam computed tomography (CBCT) and fusion imaging (FI). MATERIALS AND METHODS: Eight patients with T2EL were treated with DPSI using CBCT as imaging guidance. Anatomical landmarks on unenhanced CBCT were used for referencing T2EL location in the first five patients, while FI between unenhanced CBCT and pre-procedural computed tomography angiography (CTA) was used in the remaining three patients. Embolization was performed with thrombin, glue, and ethylene­vinyl alcohol copolymer. Technical and clinical success, iodinated contrast utilization, procedural time, fluoroscopy time, and mean radiation dose were registered. RESULTS: DPSI was technically successful in all patients: the needle was correctly positioned at the first attempt in six patients, while in two of the first five patients the needle was repositioned once. Neither minor nor major complications were registered. Average procedural time was 45 min and the average administered iodinated contrast was 13 ml. Mean radiation dose of the procedure was 60.43 Gy cm2 and mean fluoroscopy time was 18 min. Clinical success was achieved in all patients (mean followup of 36 months): no sign of T2EL was reported in seven patients until last CT follow-up, while it persisted in one patient with stability of sac diameter. CONCLUSIONS: DPSI using unenhanced CBCT and FI is feasible and provides the interventional radiologist with an accurate and safe alternative to endovascular treatment with limited iodinated contrast utilization.

Usefulness of Cone-Beam Computed Tomography and Automatic Vessel Detection Software in Emergency Transarterial Embolization.

BACKGROUND: This study was designed to evaluate the utility of dual phase cone beam computed tomography (DP-CBCT) and automatic vessel detection (AVD) software to guide transarterial embolization (TAE) of angiographically challenging arterial bleedings in emergency settings. METHODS: Twenty patients with an arterial bleeding at computed tomography angiography and an inconclusive identification of the bleeding vessel at the initial 2D angiographic series were included. Accuracy of DP-CBCT and AVD software were defined as the ability to detect the bleeding site and the culprit arterial bleeder, respectively. Technical success was defined as the correct positioning of the microcatheter using AVD software. Clinical success was defined as the successful embolization. Total volume of iodinated contrast medium and overall procedure time were registered. RESULTS: The bleeding site was not detected by initial angiogram in 20% of cases, while impossibility to identify the bleeding vessel was the reason for inclusion in the remaining cases. The bleeding site was detected by DP-CBCT in 19 of 20 (95%) patients; in one case CBCT-CT fusion was required. AVD software identified the culprit arterial branch in 18 of 20 (90%) cases. In two cases, vessel tracking required manual marking of the candidate arterial bleeder. Technical success was 95%. Successful embolization was achieved in all patients. Mean contrast volume injected for each patient was 77.5 ml, and mean overall procedural time was 50 min. CONCLUSIONS: C-arm CBCT and AVD software during TAE of angiographically challenging arterial bleedings is feasible and may facilitate successful embolization. Staff training in CBCT imaging and software manipulation is necessary.

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.

Intraprocedural 3D Quantification of Lipiodol Deposition on Cone-Beam CT Predicts Tumor Response After Transarterial Chemoembolization in Patients with Hepatocellular Carcinoma.

PURPOSE: To evaluate whether intraprocedural 3D quantification of Lipiodol deposition on cone-beam computed tomography (CBCT) can predict tumor response on follow-up contrast-enhanced magnetic resonance imaging (CE-MRI) in patients with hepatocellular carcinoma (HCC) treated with conventional transarterial chemoembolization (cTACE). MATERIALS AND METHODS: This IRB approved, retrospective analysis included 36 patients with 51 HCC target lesions, who underwent cTACE with CBCT. CE-MRI was acquired at baseline and 1 month after cTACE. Overall tumor volumes as well as intratumoral Lipiodol volumes on CBCT were measured and compared with the overall and necrotic (non-enhancing) tumor volumes on CE-MRI using the paired student's t test. Tumor response on CE-MRI was assessed using modified response evaluation criteria in solid tumors (mRECIST). A linear regression model was used to correlate tumor volumes, Lipiodol volumes, and the percentage of Lipiodol deposition on CBCT with the corresponding parameters on CE-MRI. Nonparametric spearman rank-order correlation and trend test were used to correlate the percentage of Lipiodol deposition in the tumor with tumor response. RESULT: A strong correlation between overall tumor volumes on CBCT and CE-MRI was observed (R(2) = 0.986). In addition, a strong correlation was obtained between the volume of Lipiodol deposition on CBCT and tumor necrosis (in cm(3)) on CE-MRI (R(2) = 0.960), and between the percentage of Lipiodol deposition and tumor necrosis (R(2) = 0.979). Importantly, the extent of Lipiodol deposition (in percentage of total tumor volume) correlated strongly with tumor response on CE-MRI (Spearman rho = 0.84, p < 0.001). CONCLUSIONS: Intraprocedural 3D quantification of Lipiodol deposition on CBCT can be used to predict tumor response on follow-up CE-MRI.