Spatial Omics Imaging of Fresh-Frozen Tissue and Routine FFPE Histopathology of a Single Cancer Needle Core Biopsy: A Freezing Device and Multimodal Workflow.

The complex molecular alterations that underlie cancer pathophysiology are studied in depth with omics methods using bulk tissue extracts. For spatially resolved tissue diagnostics using needle biopsy cores, however, histopathological analysis using stained FFPE tissue and the immunohistochemistry (IHC) of a few marker proteins is currently the main clinical focus. Today, spatial omics imaging using MSI or IRI is an emerging diagnostic technology for the identification and classification of various cancer types. However, to conserve tissue-specific metabolomic states, fast, reliable, and precise methods for the preparation of fresh-frozen (FF) tissue sections are crucial. Such methods are often incompatible with clinical practice, since spatial metabolomics and the routine histopathology of needle biopsies currently require two biopsies for FF and FFPE sampling, respectively. Therefore, we developed a device and corresponding laboratory and computational workflows for the multimodal spatial omics analysis of fresh-frozen, longitudinally sectioned needle biopsies to accompany standard FFPE histopathology of the same biopsy core. As a proof-of-concept, we analyzed surgical human liver cancer specimens using IRI and MSI with precise co-registration and, following FFPE processing, by sequential clinical pathology analysis of the same biopsy core. This workflow allowed for a spatial comparison between different spectral profiles and alterations in tissue histology, as well as a direct comparison for histological diagnosis without the need for an extra biopsy.

Prostatic Artery Embolization for Treatment of Lower Urinary Tract Symptoms: A Markov Model-Based Cost-Effectiveness Analysis.

PURPOSE: The aim of this study was to investigate whether prostatic artery embolization (PAE) can be considered a long-term cost-effective treatment option in patients with lower urinary tract symptoms secondary to benign prostatic hyperplasia in comparison to transurethral resection of the prostate (TURP). METHODS: The in-hospital costs of PAE and TURP in the United States were obtained from a recent cost analysis. Clinical outcomes including nature and rate of adverse events for TURP and PAE along with rates of retreatment because of complications or clinical failure were obtained from peer-reviewed literature. A decision tree-based Markov model was created, analyzing long-term cost-effectiveness for TURP and PAE from a US health care sector perspective. Cost-effectiveness over a time frame of 5 years was estimated while assuming a willingness to pay of $50,000 per quality-adjusted life-year (QALY). The primary outcome was incremental cost-effectiveness ratio. RESULTS: PAE resulted in overall cost of $6,464.92 and an expected outcome of 4.566 QALYs. In comparison, TURP cost $9,221.09 and resulted in expected outcome of 4.577 QALYs per treatment. The incremental cost-effectiveness ratio for TURP was $247,732.65 per QALY. On the basis of the willingness-to-pay threshold, PAE is cost effective compared with TURP. CONCLUSIONS: On the basis of our model, PAE in comparison with TURP can be regarded as a cost-effective treatment option for patients with lower urinary tract symptoms within the US health care system.

[Modern tomography imaging techniques in urological diseases]. / Moderne Schnittbildgebung für urologische Erkrankungen.

BACKGROUND: Radiologic imaging is important for the detection, staging and follow-up of urological tumors. Basic therapy decisions for both oncological (surgical vs. systemic therapy, e.g. in testicular cancer) and non-oncological pathologies (interventional vs. conservative therapy, e.g. for ureteral stones) depend largely on the tomographic imaging performed. Due to its almost ubiquitous availability, speed and cost-effectiveness, computed tomography (CT) plays an important role not only in the clarification of abdominal trauma and non-traumatic emergencies, but also in staging and follow-up of oncological patients. However, the level of radiation exposure, impaired renal function and allergies to iodinated contrast media limit the use of CT. Magnetic resonance imaging (MRI) can be a good alternative for many areas of application in oncological and non-oncological imaging due to its high soft tissue differentiation and functional-specific protocols but without the use of ionizing radiation. AIM: In the following, the main indications of abdominal and pelvic CT and MRI in urology and their limitations are summarized. RESULTS: The areas of application between CT and MRI are increasingly overlapping, since the latest developments in CT continue to further reduce radiation exposure and increase contrast information, while the speed and robustness of MRI are significantly improving at the same time.

Robotic Assistance System for Cone-Beam Computed Tomography-Guided Percutaneous Needle Placement.

PURPOSE: The study aimed to evaluate a new robotic assistance system (RAS) for needle placement in combination with a multi-axis C-arm angiography system for cone-beam computed tomography (CBCT) in a phantom setting. MATERIALS AND METHODS: The RAS consisted of a tool holder, dedicated planning software, and a mobile platform with a lightweight robotic arm to enable image-guided needle placement in conjunction with CBCT imaging. A CBCT scan of the phantom was performed to calibrate the robotic arm in the scan volume and to plan the different needle trajectories. The trajectory data were sent to the robot, which then positioned the tool holder along the trajectory. A 19G needle was then manually inserted into the phantom. During the control CBCT scan, the exact needle position was evaluated and any possible deviation from the target lesion measured. RESULTS: In total, 16 needle insertions targeting eight in- and out-of-plane sites were performed. Mean angular deviation from planned trajectory to actual needle trajectory was 1.12°. Mean deviation from target point and actual needle tip position was 2.74 mm, and mean deviation depth from the target lesion to the actual needle tip position was 2.14 mm. Mean time for needle placement was 361 s. Only differences in time required for needle placement between in- and out-of-plane trajectories (337 s vs. 380 s) were statistically significant (p = 0.0214). CONCLUSION: Using this RAS for image-guided percutaneous needle placement with CBCT was precise and efficient in the phantom setting.

Computer tomography guided thoracoscopic resection of small pulmonary nodules in the hybrid theatre.

PURPOSE: Thoracic surgeons are currently asked to resect smaller and deeper lesions which are difficult to detect thoracoscopically. The growing number of those lesions arises both from lung cancer screening programs and from follow-up of extrathoracic malignancies. This study analyzed the routine use of a CT-aided thoracoscopic approach to small pulmonary nodules in the hybrid theatre and the resulting changes in the treatment pathway. METHODS: 50 patients were retrospectively included. The clinical indication for histological diagnosis was suspected metastasis in 46 patients. Technically, the radiological distance between the periphery of the lesion and the visceral pleura had to exceed the maximum diameter of the lesion for the patient to be included. A spiral wire was placed using intraoperative CT-based laser navigation to guide the thoracoscopic resection. RESULTS: The mean diameter of the lesions was 8.4 mm (SD 4.27 mm). 29.4 minutes (SD 28.5) were required on average for the wire placement and 42.3 minutes (SD 20.1) for the resection of the lesion. Histopathology confirmed the expected diagnosis in 30 of 52 lesions. In the remaining 22 lesions, 9 cases of primary lung cancer were detected while 12 patients showed a benign disease. CONCLUSION: Computer tomography assisted thoracoscopic surgery (CATS) enabled successful resection in all cases with minimal morbidity. The histological diagnosis led to a treatment change in 42% of the patients. The hybrid-CATS technique provides good access to deeply located small pulmonary nodules and could be particularly valuable in the emerging setting of lung cancer screening.

Automated Screening for Abdominal Aortic Aneurysm in CT Scans under Clinical Conditions Using Deep Learning.

Abdominal aortic aneurysms (AAA) may remain clinically silent until they enlarge and patients present with a potentially lethal rupture. This necessitates early detection and elective treatment. The goal of this study was to develop an easy-to-train algorithm which is capable of automated AAA screening in CT scans and can be applied to an intra-hospital environment. Three deep convolutional neural networks (ResNet, VGG-16 and AlexNet) were adapted for 3D classification and applied to a dataset consisting of 187 heterogenous CT scans. The 3D ResNet outperformed both other networks. Across the five folds of the first training dataset it achieved an accuracy of 0.856 and an area under the curve (AUC) of 0.926. Subsequently, the algorithms performance was verified on a second data set containing 106 scans, where it ran fully automated and resulted in an accuracy of 0.953 and an AUC of 0.971. A layer-wise relevance propagation (LRP) made the decision process interpretable and showed that the network correctly focused on the aortic lumen. In conclusion, the deep learning-based screening proved to be robust and showed high performance even on a heterogeneous multi-center data set. Integration into hospital workflow and its effect on aneurysm management would be an exciting topic of future research.

Contralateral Liver Hypertrophy and Oncological Outcome Following Radioembolization with 90Y-Microspheres: A Systematic Review.

Radioembolization with 90Y-microspheres has been reported to induce contralateral liver hypertrophy with simultaneous ipsilateral control of tumor growth. The aim of the present systematic review was to summarize the evidence of contralateral liver hypertrophy and oncological outcome following unilateral treatment with radioembolization. A systematic literature search using the MEDLINE, EMBASE, and Cochrane libraries for studies published between 2008 and 2020 was performed. A total of 16 studies, comprising 602 patients, were included. The median kinetic growth rate per week of the contralateral liver lobe was 0.7% and declined slightly over time. The local tumor control was 84%. Surgical resection after radioembolization was carried out in 109 out of 362 patients (30%). Although the available data suggest that radioembolization prior to major hepatectomy is safe with a promising oncological outcome, the definitive role of radioembolization requires assessment within controlled clinical trials.

Clinical and Quantitative MRI Perfusion Analysis of Osteoid Osteomas Before and After Microwave Ablation.

AIM: Evaluation of osteoid osteoma (OO) perfusion characteristics pre and post microwave ablation (MWA) using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) with clinical follow-up. MATERIALS AND METHODS: Patients with OO underwent T1-weighted 3D DCE-MRI at 3.0T pre and post MWA. Signal intensity (SI) and perfusion of lesions was measured. Patients answered a questionnaire for clinical follow-up. RESULTS: A total of 24 patients were included (mean age of 28 years; nine females); 21 DCE-MRI datasets were of sufficient quality for analysis. The mean SI of lesions, plasma flow, volume of distribution and pain level all decreased statistically significantly after ablation. CONCLUSION: Quantitative MRI-perfusion analysis allows for objective treatment evaluation after MWA of OO, plasma flow and volume of distribution seem to be reliable indicators for successful thermoablation. MWA is an effective treatment option for OO with a low risk profile and significant pain reduction after treatment.

Cardiac impact of R-wave triggered irreversible electroporation therapy.

BACKGROUND: Irreversible electroporation (IRE) is a novel tumor ablative therapy technique, using electric fields to induce apoptosis in target tissues. Whether these electric pulses of high field strength can cause cardiac damage and/or ablation-induced arrhythmias is unclear. OBJECTIVE: The purpose of this study was to systematically evaluate the safety of electrocardiogram (ECG)-gated IRE with regard to cardiac side effects. METHODS: In all patients, 12-lead ECG and signal-averaged ECG (SAECG) recordings were performed before and after IRE and 24-hour Holter recording on the day of the IRE procedure. Venous blood samples (N-terminal pro-brain-type natriuretic peptide [NT-proBNP], high-sensitive troponin I [hsTnI]) were obtained before and 4 and 16 hours after the procedure. Patients with abnormal findings were reevaluated after 3 months. RESULTS: In total, 26 patients with an oncologic indication for IRE (11 females, mean age 62.9 years) were prospectively enrolled. Nine patients (34.6%) showed an increase in hsTnI and 21 patients (80.8%) an increase in NT-proBNP after ablation. Fifteen patients (57%) developed arrhythmias related to the procedure. One patient, in whom hsTnI and NT-proBNP had increased, developed multiple, nonsustained ventricular tachycardia events. In another patient, atrial fibrillation was triggered twice in 2 separate procedures. Twelve patients had clinically benign arrhythmias. SAECG was negative in all patients. CONCLUSION: Subclinical myocardial injury and nonfatal cardiac arrhythmias can occur in the context of IRE treatment. Although no sustained cardiac injuries could be found at 3-month follow-up, we propose implementation of a cardiac safety algorithm consisting of cardiac biomarkers and ECG monitoring when IRE is conducted.

Performance of a Robotic Assistance Device in Computed Tomography-Guided Percutaneous Diagnostic and Therapeutic Procedures.

PURPOSE: To evaluate a commercially available robotic assistance device for computed tomography-guided diagnostic and therapeutic interventions, compared to regular, manually performed CT scan-guided interventions in terms of precision, exposure to radiation to the patient and intervention time. MATERIALS AND METHODS: Over a period of 6 months, 55 consecutive patients were recruited and treated using robotic assistance and compared to a control group of 101 patients previously treated with a regular CT scan-guided, manual approach. Evaluated parameters were precision (deviation from planned target and number of needle replacements), radiation exposure to the patient and intervention time. Evaluations were performed with regard to complexity (in-plane vs out-of-plane interventions) and type of anesthesia (general vs local). RESULTS: Parameters related to precision were in general significantly better in the robotic assistance group (p < 0.01) with a mean deviation of 1.2 mm (± 1.6 mm) compared to 2.6 mm (± 1.1 mm) in the comparison group. Compared to manual procedure, the mean intervention time was reduced by 15 min (± 5.4 min) on average for an out-of-plane needle placement in the robotic group. There was no increase of exposure to radiation to the patient while radiation exposure for the physician was reduced to zero when the navigation system was used. CONCLUSION: Compared to manual placement, the use of a robotic assistance device in out-of-plane CT-guided interventions under general anesthesia allows for probe placement with high precision. Intervention time is reduced with no increase of exposure to radiation to the patient.

Parenchymal Liver Blood Volume and Dynamic Volume Perfusion CT Measurements of Hepatocellular Carcinoma in Patients Undergoing Transarterial Chemoembolization.

AIM: Prospective comparison of cone beam C-Arm CT based parenchymal liver blood volume (PLBV) and dynamic volume perfusion CT (dVPCT) measurements in patients with hepatocellular carcinoma (HCC) undergoing transarterial chemoembolisation (TACE) with drug-eluting beads (DEB). PATIENTS AND METHODS: In 16 patients, changes of PLBV and dVPCT measurements [arterial liver parenchyma (ALP); temporal maximum intensity projection (MIP); hepatic perfusion index (HPI); portal venous parenchyma] were correlated to one another and to the modified Response Evaluation Criteria in Solid Tumors (mRECIST). RESULTS: After TACE, the following parameters showed a statistically significant change (p<0.05) in mean value: PLBV: -4.85 ml/100 ml, ALP: -4.14 ml/100 ml/min, MIP: -0.23 Houndsfield units, HPI: -5.39%, and mRECIST: -20.53 mm. Pre-to-post TACE differences in PLBV showed only weak to very weak correlation to dVPCT parameters (r2<0.24). CONCLUSION: Although PLBV and dVPCT parameters showed only a weak to very weak correlation, both methods validly assessed changes in arterial tumor vascularity after DEB TACE.

Treatment Evaluation of Flow-Limiting Stenoses of the Superficial Femoral and Popliteal Artery by Parametric Color-Coding Analysis of Digital Subtraction Angiography Series.

PURPOSE: To evaluate the hemodynamic effect of percutaneous transluminal intervention (PTI) on stenosis of the superficial femoral (SFA) and popliteal arteries (PA) using time-density curves (TDCs) derived from digital subtraction angiography (DSA) series in correlation with ultrasound peak systolic velocity ratio (PSVR) and ankle brachial index (ABI). MATERIALS AND METHODS: DSA series of SFA or PA of patients with symptomatic peripheral arterial occlusive disease was obtained with a flat-panel angiography system with intention-to-treat. In DSA series acquired before and after PTI, TDCs were analyzed proximal and distal of each stenosis using parametric color coding (PCC). For correlation, ABI and PSVR measurements pre- and post-PTI were recorded for all patients. RESULTS: In total, 25 stenoses of the SFA or PA were treated by PTI in 22 patients (17 male, 5 female, mean age 68 years). After treatment, peak-to-peak (PTP) times between TDCs proximal and distal to the treated vessel segment decreased statistically significantly (p = 0.01) on average from PTP = 1.9 ± 1.7 s to mean PTP = 1 ± 1 s. ABI and PSVR also changed statistically significantly after treatment (pretreatment ABI = 0.7 ± 0.2, PSVR = 4.2 ± 1.9; post-ABI = 0.9 ± 0.2, PSVR = 1.3 ± 0.4, both p < 0.05). Correlation parameters did not show a strong correlation between change in TDC and clinical parameters ABI and PSVR. CONCLUSION: Using PCC for analyzing contrast medium dynamics in DSA series is clinically useful for evaluating stenoses of the SFA and PA and for immediate treatment control after PTA. LEVEL OF EVIDENCE: Case series, IV.

Computed Tomography-Assisted Thoracoscopic Surgery: A Novel, Innovative Approach in Patients With Deep Intrapulmonary Lesions of Unknown Malignant Status.

OBJECTIVES: Minimally invasive resection of small, deep intrapulmonary lesions can be challenging due to the difficulty of localizing them during video-assisted thoracoscopic surgery (VATS). We report our preliminary results evaluating the feasibility of an image-guided, minimally invasive, 1-stop-shop approach for the resection of small, deep intrapulmonary lesions in a hybrid operating room (OR). MATERIALS AND METHODS: Fifteen patients (5 men, 10 women; mean age, 63 years) with a total of 16 solitary, deep intrapulmonary nodules of unknown malignant status were identified for intraoperative wire marking. Patients were placed on the operating table for resection by VATS. A marking wire was placed within the lesion under 3D laser and fluoroscopic guidance using a cone beam computed tomography system. Then, wedge resection by VATS was performed in the same setting without repositioning the patient. RESULTS: Complete resection with adequate safety margins was confirmed for all lesions. Marking wire placement facilitated resection in 15 of 16 lesions. Eleven lesions proved to be malignant, either primary or secondary; 5 were benign. Mean lesion size was 7.7 mm; mean distance to the pleural surface was 15.1 mm (mean lesion depth-diameter ratio, 2.2). Mean procedural time for marking wire placement was 35 minutes; mean VATS duration was 36 minutes. CONCLUSIONS: Computed tomography-assisted thoracoscopic surgery is a new, safe, and effective procedure for minimally invasive resection of small, deeply localized intrapulmonary lesions. The benefits of computed tomography-assisted thoracoscopic surgery are 1. One-stop-shop procedure, 2. Lower risk for the patient (no patient relocation, no marking wire loss), and 3. No need to coordinate scheduling between the CT room and OR.

Automated Vessel Segmentation in Dual Energy Computed Tomography Data of the Pelvis and Lower Extremities.

AIM: To evaluate the clinical feasibility of a newly developed, fully automatic vessel segmentation software with automatic structured bone elimination (ASBE) using graph-matching and subvoxel analysis. MATERIALS AND METHODS: Dual energy computed tomography angiography (DECTA) data of 108 vessel segments were evaluated using the ASBE software and a commercial software against the digital subtraction angiography (DSA) standard of reference. RESULTS: Using the ASBE software, sensitivity increased from 87.1% to 96.8% and data concordance with DSA increased from 64.5% to 88.6%, whereas specificity slightly decreased (79.2% vs. 87%) compared to the commercial software. Data concordance between ASBE software and DSA was especially high in severely stenosed (grade of stenosis >75%) blood vessels. CONCLUSION: ASBE showed good concordance with the DSA standard of reference and non-inferiority compared to the commercial segmentation software. The main advantage of the ASBE software lies in its full automation and, thus, lower susceptibility to user prone errors.

Benefit of Patients with an Early and Progressed State of Hepatocellular Carcinoma Treated with Drug-eluting Beads.

AIM: To evaluate drug-eluting beads (DEB) for transarterial chemoembolization (TACE) in patients with Barcelona Clinic Liver Cancer (BCLC) A to D suffering from hepatocellular carcinoma. MATERIAL AND METHODS: The progression-free interval (PFI), survival and laboratory findings of 46 patients were retrospectively analyzed after DEB TACE. RESULTS: The mean survival interval was 16.93 months. The BCLC A/B group had significantly (p=0.01) longer survival compared to C/D: 20.44 and 10.36 months. Mean PFI was 10.75 months with a significantly (p=0.002) longer PFI of the BCLC A/B group (12.71 months) compared to BCLC C/D (3.91 months). In terms of possible adverse events (AEs) significant changes (p<0.05) were observed in cholinesterase, white blood cells, alkaline phosphatase and C-reactive protein. CONCLUSION: Mean survival and PFI results in the BCLC A/B patient group were comparable to historical controls. In addition, the results suggest that patients with BCLC stage C/D also benefited from DEB TACE.

Semi-automatic Volumetric Measurement of Treatment Response in Hepatocellular Carcinoma After Trans-arterial Chemoembolization.

AIM: To perform a quantitative, volumetric analysis of therapeutic effects of trans-arterial chemoembolization (TACE) in hepatocellular carcinoma (HCC) patients. PATIENTS AND METHODS: Entire tumor volume and a subset of hypervascular tumor portions were analyzed pre- and post-TACE in magnetic resonance imaging datasets of 22 HCC patients using a semi-automated segmentation and evaluation tool from the Medical Imaging Interaction Toolkit. Results were compared to mRECIST measurements and inter-reader variability was assessed. RESULTS: Mean total tumor volume increased statistical significantly after TACE (84.6 ml pre- vs. 97.1 ml post-TACE, p=0.03) while hypervascular tumor volume decreased from 9.1 ml pre- to 3.7 ml post-TACE (p=0.0001). Likewise, mRECIST diameters decreased significantly after therapy (44.2 vs. 15.4 mm). In the inter-reader assessment, overlap errors were 12.3-17.7% for entire and 36.3-64.2% for the enhancing tumor volume. CONCLUSION: Quantification of therapeutic changes after TACE therapy is feasible using a semi-automated segmentation and evaluation tool. Following TACE, hypervascular tumor volume decreases significantly.

Semiautomatic Whole-lesion Apparent Diffusion Coefficient Assessment for Early Prediction of Liver Tumor Response to Radioembolization.

AIM: To evaluate volume-based apparent diffusion coefficient (ADCVOL) values for early prediction of therapy response after radioembolization (RE) of primary and secondary liver malignancies using a semiautomatic, image analysis software prototype. PATIENTS AND METHODS: In a retrospective analysis, 74 target lesions were assessed in terms of therapy response 1 month after RE using magnetic resonance imaging. Changes of the diameter of the target lesions, the mean ADC value in a representative single-slice region of interest (ADCROI) and mean ADCVOL were correlated. RESULTS: The median progression-free interval (PFI) of patients overall was 3.5±5.9 months. PFI in patients with an ADCVOL increase was statistically significantly longer than in patients with an ADCVOL decrease (mean PFI=6.5 vs. 2.5 months; p=0.0374). No correlation between PFI and early changes in lesion diameter or ADCROI was found. CONCLUSION: Semiautomatic, software-based ADC volume measurements seem to offer a clinically valuable parameter for early prediction of therapy response in patients after RE.

Irreversible Electroporation for Surgical Renal Masses in Solitary Kidneys: Short-Term Interventional and Functional Outcome.

PURPOSE: To examine short-term outcomes and complications in patients with a solitary kidney treated with irreversible electroporation (IRE) for a potentially malignant renal mass. MATERIALS AND METHODS: Five patients (2 female, 3 male; mean age, 66 y) with 7 lesions who underwent IRE for renal tumors in a solitary kidney between August 2014 and August 2015 were retrospectively reviewed. Changes in signal intensity (SI) of the treated lesion were evaluated on contrast-enhanced magnetic resonance imaging. To evaluate functional outcome, creatinine levels and estimated glomerular filtration rate (eGFR) were compared vs baseline after 1 day, 2-7 days, 3-6 weeks, and 6-12 weeks after the intervention. RESULTS: Mean tumor diameter was 24.4 mm (range, 15-38 mm), with an average score of 7.7 (range, 4-9) per R.E.N.A.L. criteria (radius, exophytic/endophytic, nearness to collecting system or sinus, anterior/posterior, and location relative to polar lines). There was a progressive, significant decrease in treated tumor SI on follow-up imaging (mean, 70%-82%), suggesting a treatment response rate of 100% at a mean follow-up of 6.4 months (range, 3-11 mo). Two minor acute complications (Society of Interventional Radiology class A) occurred: transient gross hematuria and stage I acute kidney failure. Overall, there was no significant decrease in eGFR (-2.75 mL/min) over 3 months, even though 1 patient's eGFR decreased from > 60 mL/min/1.73m(2) to 44 mL/min/1.73m(2). CONCLUSIONS: The data suggest that percutaneous IRE for renal mass in patients with a solitary kidney is safe and feasible. It may help to preserve renal function and offers promising short-term oncologic results.

Radiation exposure of the interventional radiologist during percutaneous biopsy using a multiaxis interventional C-arm CT system with 3D laser guidance: a phantom study.

OBJECTIVE: Evaluation of absolute radiation exposure values for interventional radiologists (IRs) using a multiaxis interventional flat-panel C-arm cone beam CT (CBCT) system with three-dimensional laser guidance for biopsy in a triple-modality, abdominal phantom. METHODS: In the phantom, eight lesions were punctured in two different angles (in- and out-of-plane) using CBCT. One C-arm CT scan was performed to plan the intervention and one for post-procedural evaluation. Thermoluminescent dosemeters (TLDs) were used for dose measurement at the level of the eye lens, umbilicus and ankles on a pole representing the IRs. All measurements were performed without any lead protection. In addition, the dose-area product (DAP) and air kerma at the skin entrance point was documented. RESULTS: Mean radiation values of all TLDs were 190 µSv for CBCT (eye lens: 180 µS, umbilicus: 230 µSv, ankle: 150 µSv) without a significant difference (p > 0.005) between in- and out-of-plane biopsies. In terms of radiation exposure of the phantom, the mean DAP was not statistically significantly different (p > 0.05) for in- and out-of-plane biopsies. Fluoroscopy showed a mean DAP of 7 or 6 µGym(2), respectively. C-arm CT showed a mean DAP of 5150 or 5130 µGym(2), respectively. CONCLUSION: In our setting, the radiation dose to the IR was distinctly high using CBCT. For dose reduction, it is advisable to pay attention to lead shielding, to increase the distance to the X-ray source and to leave the intervention suite for C-arm CT scans. ADVANCES IN KNOWLEDGE: The results indicate that using modern navigation tools and CBCT can be accompanied with a relative high radiation dose for the IRs since detector angulation can make the use of proper lead shielding difficult.

Accuracy of percutaneous soft-tissue interventions using a multi-axis, C-arm CT system and 3D laser guidance.

INTRODUCTION: Purpose of this phantom study was to compare the accuracy of needle placement using a multi-axis, C-arm-based, flat-panel, cone-beam computed tomography system (CBCT guidance) with that under multi-detector computed tomography guidance (MDCT guidance). MATERIALS AND METHODS: In an abdominal phantom, eight lesions (six lesions in the liver and two in the renal pelvises, respectively) were each punctured in-plane and off-plane with a 20G needle under CBCT and MDCT guidance. Access paths were initially defined and reproduced identically on the two systems. In total, 32 interventions were conducted. CBCT and MDCT guidance was compared prospectively with respect to technical success, accuracy, and overall procedural time. RESULTS: All 32 interventions were technically successful in that it was possible to hit the respective lesion in each procedure. When comparing the accuracy of MDCT to CBCT guidance there was no significant difference in absolute, angular, and longitudinal deviation for either in- or off-plane interventions. Overall procedural duration was significantly longer under CBCT guidance for in-plane interventions (888 vs 527s, p=0.00005), whereas, for off-plane procedures there was no significant difference between CBCT and MDCT guidance (920 vs 701s, p=0.08). Off-plane interventions took significantly longer than in-plane interventions under MDCT guidance (701 vs 527s, p=0.03), whereas under CBCT guidance no significant difference could be found between off- and in-plane procedures (920 vs. 888s, p=0.2). CONCLUSIONS: In this phantom study, we could show that percutaneous soft-tissue interventions under CBCT guidance can be conducted with an accuracy comparable to that under MDCT guidance. Although overall procedural duration is in general shorter using MDCT guidance, CBCT-guided interventions offer the advantage of more degrees of freedom, which is of particular importance for off-plane procedures.