Parallel Guidewire for Catheter Stabilization in Interventional Radiology: The Anchoring Wire Technique.

This technical note describes the parallel guidewire method: the anchoring technique as a strategy to ease difficult catheterization in various endovascular interventions. Sixteen patients were included in 2017 in whom this technique was used. The type of intervention, the nature of the target and anchored vessels and possible complications on the anchored vessel were reported. This study included thirteen various embolization cases and four visceral vessels angioplasties cases. The success of catheterization by using this technique was achieved in all cases, without complication on the anchored vessels.

CBCT-Based Image Guidance for Percutaneous Access: Electromagnetic Navigation Versus 3D Image Fusion with Fluoroscopy Versus Combination of Both Technologies-A Phantom Study.

PURPOSE: We set out to compare three types of three-dimensional CBCT-based imaging guidance modalities in a phantom study: image fusion with fluoroscopy (IF), electromagnetic navigation (EMN) and the association of both technologies (CEMNIF). MATERIALS AND METHODS: Four targets with a median diameter of 11 mm [first quartile (Q1): 10; third quartile (Q3): 12] with acute angle access (z-axis < 45°) and four targets of 10 mm [8-15] with large angle access (z-axis > 45°) were defined on an abdominal phantom (CIRS, Meditest, Tabuteau, France). Acute angle access targets were punctured using IF, EMN or CEMNIF and large angle access targets with EMN by four operators with various experiences. Efficacy (target reached), accuracy (distance between needle tip and target center), procedure time, radiation exposure and reproducibility were explored and compared. RESULTS: All targets were reached (100% efficacy) by all operators. For targets with acute angle access, procedure times (EMN: 265 s [236-360], IF: 292 s [260-345], CEMNIF: 320 s [240-333]) and accuracy (EMN: 3 mm [2-5], IF: 2 mm [1-3], CEMNIF: 3 mm [2-4]) were similar. Radiation exposure (EMN: 0; IF: 708 mGy.cm2 [599-1128]; CEMNIF: 51 mGy.cm2 [15-150]; p < 0.001) was significantly higher with IF than with CEMNIF and EMN. For targets with large angle access, procedure times (EMN: 345 s [259-457], CEMNIF: 425 s [340-473]; p = 0.01) and radiation exposure (EMN: 0, CEMIF: 159 mGy.cm2 [39-316]; p < 0.001) were significantly lower with EMN but with lower accuracy (EMN: 4 mm [4-6] and CEMNIF: 4 mm [3, 4]; p = 0.01). The operator's experience did not impact the tested parameters regardless of the technique. CONCLUSION: In this phantom study, EMN was not limited to acute angle targets. Efficacy and accuracy of puncture for acute angle access targets with EMN, IF or CEMNIF were similar. CEMNIF is more accurate for large angle access targets at the cost of a slightly higher procedure time and radiation exposure.

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.

Differentiating focal nodular hyperplasia from hepatocellular adenoma: Is hepatobiliary phase MRI (HBP-MRI) using linear gadolinium chelates always useful?

PURPOSE: To assess the value of Hepatobiliary phase MRI (HPB-MRI) to differentiate FNH and HCA, and evaluate its impact on diagnostic accuracy, diagnostic confidence, inter-observer variability, and patient clinical management. METHODS: Forty-nine patients referred for Gd-BOPTA-enhanced MRI were retrospectively included in this IRB-approved study, with a total of 119 lesions-90 FNH and 29 HCA. Two observers separately assessed in 2 distinct randomized reading sessions the performance of MRI with (HBP-MRI) or without (conventional MRI) the use of HBP images. Each lesion was ranked with a 5-point scale (from 1 Typical FNH to 5 Certainly not a FNH). Sensitivity, specificity, overall accuracy, and inter-observer agreement for the differentiation of FNH from HCA were calculated and compared between conventional and HBP-MRI. RESULTS: Both sensitivity (respective values of 38.9% and 97.8%), overall accuracy (respective values of 53.8% and 98.3%), and inter-observer agreement (respective values of Kappa 0.56 and 0.88) were significantly higher using HBP-MRI than with conventional MRI, with unchanged specificity (100%). The sensitivity of conventional MRI for the diagnosis of FNH was significantly lower in lesions ≤ 3 cm (20% vs. 88%). Overall, HBP could have changed lesion management in 59/119 cases (49.5%), including 53 FNH and 6 HCA with no impact in 60/119 lesions (50.5%) including all 35 lesions classified as scores 1 and 2 for the diagnosis of FNH. CONCLUSIONS: The clinical impact of HBP-MRI is mostly important for smaller than 3-cm FNH, and more limited in larger FNH lesions as well as for HCA diagnosis for which conventional MRI is already accurate. The use of extracellular contrast agents upfront could limit the required use of linear HBP contrast agents for benign hepatocellular lesion characterization. On HBP, all FNH appeared hypointense compared to adjacent liver while close to 97% of HCA appeared hypointense.

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.

Correction to: Differentiating focal nodular hyperplasia from hepatocellular adenoma: Is hepatobiliary phase MRI (HBP-MRI) using linear gadolinium chelates always useful?

The original version of this article unfortunately contained a mistake. There was an error in the last sentence of the summary and the last sentence of the discussion. It should read as "On HBP, all FNH appeared hyper- or iso-intense compared to adjacent liver while close to 97% of HCA appeared hypointense".

Three-dimensional Image Fusion Guidance for Transjugular Intrahepatic Portosystemic Shunt Placement.

INTRODUCTION: To assess the safety, feasibility and effectiveness of image fusion guidance with pre-procedural portal phase computed tomography with intraprocedural fluoroscopy for transjugular intrahepatic portosystemic shunt (TIPS) placement. MATERIALS AND METHODS: All consecutive cirrhotic patients presenting at our interventional unit for TIPS creation from January 2015 to January 2016 were prospectively enrolled. Procedures were performed under general anesthesia in an interventional suite equipped with flat panel detector, cone-beam computed tomography (CBCT) and image fusion technique. All TIPSs were placed under image fusion guidance. After hepatic vein catheterization, an unenhanced CBCT acquisition was performed and co-registered with the pre-procedural portal phase CT images. A virtual path between hepatic vein and portal branch was made using the virtual needle path trajectory software. Subsequently, the 3D virtual path was overlaid on 2D fluoroscopy for guidance during portal branch cannulation. Safety, feasibility, effectiveness and per-procedural data were evaluated. RESULTS: Sixteen patients (12 males; median age 56 years) were included. Procedures were technically feasible in 15 of the 16 patients (94%). One procedure was aborted due to hepatic vein catheterization failure related to severe liver distortion. No periprocedural complications occurred within 48 h of the procedure. The median dose-area product was 91 Gy cm2, fluoroscopy time 15 min, procedure time 40 min and contrast media consumption 65 mL. Clinical benefit of the TIPS placement was observed in nine patients (56%). CONCLUSION: This study suggests that 3D image fusion guidance for TIPS is feasible, safe and effective. By identifying virtual needle path, CBCT enables real-time multiplanar guidance and may facilitate TIPS placement.

Functional imaging of hepatocellular carcinoma using diffusion-weighted MRI and (18)F-FDG PET/CT in patients on waiting-list for liver transplantation.

BACKGROUND: To compare the apparent diffusion coefficient (ADC) on diffusion-weighted imaging (DWI) with the standardized uptake values (SUV) measured by(18)F-FDG-PET/CT in naïve hepatocellular carcinoma (HCC) nodules, and to determine whether these markers are associated with tumours at high-risk of aggressiveness. METHODS: From 2007 to 2010, all patients with HCC on the waiting list for liver transplantation and who underwent both FDG-PET/CT and 1.5-T DWI-MRI (b values: 0, 200, 400, and 800 s/mm(2)) were included in this institutional review board-approved retrospective study. Tumour size, tumour ADC, tumour-to-liver ADC ratio (ADCT/L), maximal tumour SUV and tumour-to-liver SUV ratio (SUVT/L) were measured and compared to serum alpha-fetoprotein (AFP) levels, tumour size and differentiation grade on explanted specimens. RESULTS: A total of 37 HCC nodules in 28 patients were available for correlation between MRI and PET/CT, 7 of which (in 7 patients) showed a SUVT/L > 1.15. We did not find any correlation between tumour ADC or ADCT/L and tumour SUV or SUVT/L. To note, SUVT/L was positively correlated with AFP levels (R = 0.95, P ≤ 0.0001), while ADCT/L was not (P = 0.73). Twenty-four patients (with 32 nodules) underwent liver transplantation. In this subgroup, an increased SUVT/L ratio was associated with larger tumours (average size, 32 ± 14 mm; range, 18-60 mm; P < 0.0001) and with poor differentiation on pathology (grades 3 and 4; P = 0.04), while ADCT/L was neither associated with tumour size or differentiation grade. CONCLUSIONS: ADC and SUV measures in HCC nodules are not correlated. SUVT/L ratio correlates with AFP levels, tumour size and poor differentiation, and should probably be integrated as a co-variable in a predictive outcome model of patients on the waiting-list for liver transplantation.

Cone-Beam CT Angiography for Determination of Tumor-Feeding Vessels During Chemoembolization of Liver Tumors: Comparison of Conventional and Dedicated-Software Analysis.

PURPOSE: To compare the ability of dedicated software and conventional cone-beam computed tomography (CT) analysis to identify tumor-feeding vessels in hypervascular liver tumors treated with chemoembolization. MATERIAL AND METHODS: Between January 2012 and January 2013, 45 patients (32 men, mean age of 61 y; range, 27-85 y) were enrolled, and 66 tumors were treated (mean, 32 mm ± 18; range, 10-81 mm) with conventional chemoembolization with arterial cone-beam CT. Data were independently analyzed by six interventional radiologists with standard postprocessing software, a computer-aided analysis with FlightPlan for liver (FPFL; ie, "raw FPFL"), and a review of this computer-aided FPFL analysis ("reviewed FPFL"). Analyses were compared with a reference reading established by two study supervisors in consensus who had access to all imaging data. Sensitivities, positive predictive values (PPVs), and false-positive (FP) ratios were compared by McNemar, χ(2), and Fisher exact tests. Analysis durations were compared by Mann-Whitney test, and interreader agreement was assessed. RESULTS: Reference reading identified 179 feeder vessels. The sensitivity of raw FPFL was significantly higher than those of reviewed FPFL and conventional analyses (90.9% vs 83.2% and 82.1%; P < .0001), with lower PPV (82.9% vs 91.2% and 90.6%, respectively; P < .0001), higher FP ratio (17.1% vs 9.4% and 8.8%, respectively; P < .0001), and greater interreader agreement (92% vs 80% and 79%, respectively; P < .0001). Reviewed FPFL analysis took significantly longer than both other analyses (P < .0001). CONCLUSIONS: The FPFL analysis software enabled a fast, accurate, and sensitive detection of tumor feeder vessels.

Differentiation of focal nodular hyperplasia from hepatocellular adenoma: Role of the quantitative analysis of gadobenate dimeglumine-enhanced hepatobiliary phase MRI.

PURPOSE: To determine the value of quantitative analysis of the hepatobiliary phase (HBP) in gadobenate dimeglumine (Gd-BOPTA)-enhanced magnetic resonance imaging (MRI) to differentiate focal nodular hyperplasia (FNH) from hepatocellular adenoma (HCA). MATERIALS AND METHODS: Thirty-eight patients bearing 67 lesions (40 FNH; 27 HCA) were retrospectively included in this Institutional Review Board-approved study. The same volumetric interpolated breath-hold examination (VIBE) T1 -weighted sequences were performed before and after contrast injection on a 1.5T MRI, with HBP images acquired with a mean delay of 80 minutes (range 60-120 min). After a visual assessment of lesions enhancement (qualitative HBP analysis), the HBP signal intensity ratio (SIR) and the lesion-to-liver contrast enhancement ratio (LLCER) were calculated for each lesion by two observers (Mann-Whitney test). The sensitivities, specificities (receiver operating characteristic [ROC] curve analysis) and interobserver correlation (intraclass coefficient, ICC) of quantitative HBP analysis were determined. RESULTS: All FNH and 44.4% of HCA appeared hyper- or isointense relative to the adjacent liver on qualitative HBP analysis. The mean SIR (P < 0.01) and LLCER (P < 0.0001) of FNH were significantly higher than that of HCA. The area under the ROC curve for the differentiation of FNH from HCA with LLCER was 0.98 for both observers. With a cutoff value of -0.3%-observer 1 with highest experience- LLCER assessment provided respective sensitivity and specificity values of 100% and 96.2% for the differentiation of FNH from HCA. The ICC was 0.7 for SIR measurements and 0.8 for LLCER measurements. CONCLUSION: Quantitative LLCER assessment allows an accurate differentiation of FNH from HCA, even in hyper- or isointense HCA on HBP images.

Automatic three-dimensional detection of prostatic arteries using cone-beam CT during prostatic arterial embolization.

The purpose of this study was to evaluate the automatic three-dimensional detection of prostatic arteries (PAs) with the use of dual-phase cone-beam computed tomography (CT) imaging and vessel-tracking software during prostatic artery (PA) embolization (PAE). In six patients, six right PAs and five left PAs were detected by using the software (sensitivity, 92%). The false-positive arteries (right side, 14%; left side, 25%) were deleted after cone-beam CT review. Automatic software detection of PAs from cone-beam CT may permit identification of the PA during PAE.

Use of Model-Based Iterative Reconstruction (MBIR) in reduced-dose CT for routine follow-up of patients with malignant lymphoma: dose savings, image quality and phantom study.

OBJECTIVES: To evaluate both in vivo and in phantom studies, dose reduction, and image quality of body CT reconstructed with model-based iterative reconstruction (MBIR), performed during patient follow-ups for lymphoma. METHODS: This study included 40 patients (mean age 49 years) with lymphoma. All underwent reduced-dose CT during follow-up, reconstructed using MBIR or 50 % advanced statistical iterative reconstruction (ASIR). All had previously undergone a standard dose CT with filtered back projection (FBP) reconstruction. The volume CT dose index (CTDIvol), the density measures in liver, spleen, fat, air, and muscle, and the image quality (noise and signal to noise ratio, SNR) (ANOVA) observed using standard or reduced-dose CT were compared both in patients and a phantom study (Catphan 600) (Kruskal Wallis). RESULTS: The CTDIvol was decreased on reduced-dose body CT (4.06 mGy vs. 15.64 mGy p < 0.0001). SNR was higher in reduced-dose CT reconstructed with MBIR than in 50 % ASIR or than standard dose CT with FBP (patients, p ≤ 0.01; phantoms, p = 0.003). Low contrast detectability and spatial resolution in phantoms were not altered on MBIR-reconstructed CT (p ≥ 0.11). CONCLUSION: Reduced-dose CT with MBIR reconstruction can decrease radiation dose delivered to patients with lymphoma, while keeping an image quality similar to that obtained on standard-dose CT. KEY POINTS: • In lymphoma patients, CT dose reduction is a major concern. • Reduced-dose body CT provides a fourfold radiation dose reduction. • Optimized CT reconstruction techniques (MBIR) can maintain image quality.

C-arm cone-beam computed tomography in interventional oncology: technical aspects and clinical applications.

C-arm cone-beam computed tomography (CBCT) is a new imaging technology integrated in modern angiographic systems. Due to its ability to obtain cross-sectional imaging and the possibility to use dedicated planning and navigation software, it provides an informed platform for interventional oncology procedures. In this paper, we highlight the technical aspects and clinical applications of CBCT imaging and navigation in the most common loco-regional oncological treatments.

Intravoxel incoherent motion (IVIM) MR imaging of colorectal liver metastases: are we only looking at tumor necrosis?

PURPOSE: To determine if intra-voxel incoherent motion diffusion-weighted imaging (IVIM-DWI) parameters, including free molecular-based (D) and perfusion-related (D*, f) diffusion parameters, correlate with the degree of tumor necrosis and viable tumor in colo-rectal cancer (CRC) metastasis. MATERIALS AND METHODS: Fifteen patients referred for resection of liver metastases from CRC were retrospectively included in this Institutional Review Board approved study. An IVIM-DWI sequence was performed on a 1.5 Tesla MR imaging system, with 10 b factors (0, 10, 20, 30, 50, 80, 100, 200, 400 and 800 s/mm(2) ). Mean D, D*, f and apparent diffusion coefficient (ADC) values were determined in metastases with a longest diameter above 10 mm. Correlations between the diffusion parameters and the degree of liver tumor necrosis and viable tissue were determined (Spearman). RESULTS: Correlation between diffusion parameters and histopathological findings was performed in 35 hepatic metastases with a diameter of more than 10 mm (mean size of 17.9 mm; range, 1-68 mm). Both D (r = 0.36; P = 0.035) and ADC (r = 0.4; P = 0.02) correlated with the degree of tumor necrosis but not with viable tumor. CONCLUSION: ADC variation observed in CRC metastases following systemic chemotherapy reflects a specific increase in free-molecular diffusion (D), in itself correlated to the degree of metastasis necrosis.

Liver magnetic resonance diffusion weighted imaging: 2011 update.

Diffusion-Weighted-Imaging (DWI) assesses proton motion on a cellular scale. Owing to recent instrumentation developments, diffusion sequences are now routinely used for liver imaging. This review will go through the physical principles that underlie this technique, and then highlight up-to-date liver applications including quantification of liver fibrosis, focal lesions detection and characterization, and therapy response monitoring.

Abdominopelvic extra-enteric findings at computed tomography enteroclysis: a retrospective evaluation of 430 consecutive patients.

BACKGROUND: Our objective was to retrospectively determine the frequency with which CT enteroclysis (CTE) shows abdominopelvic extra-enteric abnormalities and to analyze how such findings had actually and prospectively affected patient's care. METHODS: The CTE examinations of 430 consecutive patients were retrospectively and blindly reviewed for the presence of possible pathologic conditions that might have affected abdominopelvic organs other than the small bowel. Extra-enteric abnormalities were categorized as negligible or important and correlated with patient's outcome and thus classified as having or not influenced patient's care. RESULTS: Abdominopelvic extra-enteric abnormalities were present on CTE in 258 (60%) of 430 patients. Retrospective analysis of CTE images revealed negligible abnormalities in 217 patients (217/430, 50.5%) and important ones in 41 patients (41/430, 9.5%). Among the 41 patients with important abnormalities, CTE demonstrated already documented abnormalities in 22 patients (22/41, 53.7%) and unknown abnormalities in 19 patients (19/41, 46.3%). In the latter 19 patients, the detection of unknown abnormalities altered patient's care in 18 (94.7%) of them. In one patient (1/19, 5.3%), important abnormality was detected during retrospective evaluation but not prospectively, resulting in a delayed treatment, yielding missed important abnormality rate of 2.4% (1/41). CONCLUSIONS: Abdominopelvic extra-enteric abnormalities are frequent on CTE, but their depictions rarely alter patient's care. However, in a few patients (19/430; 4.4%), CTE may reveal unknown extra-enteric abnormalities that require further evaluation and have substantial impact on patient's management.