C-arm Cone-beam CT Research Articles

Towards patient connected imaging with ACROBEAT: Adaptive CaRdiac cOne BEAm computed Tomography

Robotic C-arm cone beam computed tomography (CBCT) systems are playing an increasingly pivotal role in interventional cardiac procedures and high precision radiotherapy treatments. One of the main challenges in any form of cardiac imaging is mitigating the intrinsic motion of the heart, which causes blurring and artefacts in the 3D reconstructed image. Most conventional 3D cardiac CBCT acquisition techniques attempt to combat heart motion through retrospective gating techniques, whereby acquired projections are sorted into the desired cardiac phase after the completion of the scan. However, this results in streaking artefacts and unnecessary radiation exposure to the patient. Here, we present our Adaptive CaRdiac cOne BEAm computed Tomography (ACROBEAT) acquisition protocol that uses the patient’s electrocardiogram (ECG) signal to adaptively regulate the gantry velocity and projection time interval in real-time. It enables prospectively gated patient connected imaging in a single sweep of the gantry. The XCAT digital software phantom was used to complete a simulation study to compare ACROBEAT to a conventional multi-sweep retrospective ECG gated acquisition, under a variety of different acquisition conditions. The effect of location and length of the acquisition window and total number of projections acquired on image quality and total scan time were examined. Overall, ACROBEAT enables up to a 5 times average improvement in the contrast-to-noise ratio, a 40% reduction in edge response width and an 80% reduction in total projections acquired compared to conventional multi-sweep retrospective ECG gated acquisition.

Can cone-beam CT tumor blood volume predicts the response to chemoembolization of colorectal liver metastases? Results of an observational study.

To determine whether intraprocedural C-arm cone-beam CT (CBCT) parenchymal blood volume (PBV) can predict the response of colorectal cancer liver metastases (CRCLM) 2months after irinotecan drug-eluting bead (DEBIRI) chemoembolization. This single-center observational study was compliant with the Helsinki Declaration and approved by our institutional review board. Thirty-four consecutive CRCLM patients referred for DEBIRI chemoembolization were enrolled between March 2015 and December 2016. Tumor size was assessed at baseline and 2months after DEBIRI chemoembolization by multidetector CT (Response Evaluation Criteria in Solid Tumors RECIST 1.0), and PBV was measured before and after DEBIRI chemoembolization. Two independent readers reviewed all data. We determined the potential correlation (Spearman's rank correlation) between intraprocedural PBV values and tumor response at 2months. The relationship between tumor response and PBV was studied using a mixed model. A logistic regression model was applied to study the relationship between patient "Responder/Non-responder" and PBV. There was a strong correlation between baseline PBV or the percent change of PBV and the 2-month tumor response (rho = - 0.8587 (p = 0.00001) and rho = 0.8027 (p = 0.00001), respectively). The mixed model showed that an increase of 1ml/1000ml in PBV of a tumor before DEBIRI chemoembolization led to a 0.54mm decrease in diameter (p < 0.005). A 1% decrease in PBV after DEBIRI chemoembolization resulted in tumor shrinkage of 0.75mm (p < 0.005). The logistic regression model showed that patients with a 1% smaller mean decrease of PBV after DEBIRI chemoembolization had a 10% lower likelihood of achieving disease control (OR = 0.9, 95% confidence interval (CI)=0.81-1; p = 0.0493). Intraprocedural PBV may predict tumor response to DEBIRI chemoembolization. • There is a strong relationship between the parenchymal blood volume (PBV) of colorectal liver metastases before DEBIRI chemoembolization and tumor response at 2months. • Higher PBV values before DEBIRI chemoembolization correlate with greater tumor shrinkage, but only if the PBV decreases by more than 70% after DEBIRI chemoembolization. • Each increase of 1% in the mean decrease of PBV after DEBIRI chemoembolization resulted in a 10% lower likelihood of achieving disease control (OR = 0.9, 95% confidence interval (CI)=0.81-1; p = 0.0493).

Virtual Guidance of Percutaneous Transthoracic Needle Biopsy with C-Arm Cone-Beam CT: Diagnostic Accuracy, Risk Factors and Effective Radiation Dose.

C-arm cone-beam computed tomography-guided transthoracic lung core needle biopsy (CBCT-CNB) is a safe and accurate procedure for the evaluation of patients with pulmonary nodules. The purpose of our study was to evaluate the diagnostic performance, complication rates and effective radiation dose of CBCT-CNB with virtual guidance. We retrospectively collected data regarding 375 CBCT-CNBs performed with virtual guidance (XperGuide-Philips Healthcare, Best, The Netherlands) from January 2010 to June 2015 on 355 patients (mean age, 68.1years ± 11.8; age range, 31-88years). Patients were divided into groups and compared based on the diagnostic failure and lesion size (15mm cutoff). Diagnostic performance, complication rate and effective radiation dose were investigated. Variables influencing diagnostic performance and complications were assessed using Student's T test and Pearson's χ2 test. The sensitivity, specificity, positive and negative predictive value and accuracy for patients subjected to CNBs were 96.8%, 100%, 100%, 100% and 97.2%, respectively. Considering risk factors for pneumothorax, no significant differences were found regarding patient and lesion characteristics. Perilesional hemorrhage occurred more frequently in older patients (p = 0.046) and in smaller lesions (p = 0.001). Hemoptysis was significantly more frequent in patients with perilesional hemorrhage (p = 0.01). Mean effective radiation dose in CBCT-CNB was 7.12 ± 8.78mSv. CBCT-CNB combined with virtual guidance is a reliable and accurate technique that allows exact localization of pulmonary lesions, effective preprocedural planning and real-time fluoroscopy altogether.

Learning Curve of C-Arm Cone-beam Computed Tomography Virtual Navigation-Guided Percutaneous Transthoracic Needle Biopsy.

ObjectiveTo evaluate the learning curve for C-arm cone-beam computed tomography (CBCT) virtual navigation-guided percutaneous transthoracic needle biopsy (PTNB) and to determine the amount of experience needed to develop appropriate skills for this procedure using cumulative summation (CUSUM).Materials and MethodsWe retrospectively reviewed 2042 CBCT virtual navigation-guided PTNBs performed by 7 novice operators between March 2011 and December 2014. Learning curves for CBCT virtual navigation-guided PTNB with respect to its diagnostic performance and the occurrence of biopsy-related pneumothorax were analyzed using standard and risk-adjusted CUSUM (RA-CUSUM). Acceptable failure rates were determined as 0.06 for diagnostic failure and 0.25 for PTNB-related pneumothorax.ResultsStandard CUSUM indicated that 6 of the 7 operators achieved an acceptable diagnostic failure rate after a median of 105 PTNB procedures (95% confidence interval [CI], 14–240), and 6 of the operators achieved acceptable pneumothorax occurrence rate after a median of 79 PTNB procedures (95% CI, 27–155). RA-CUSUM showed that 93 (95% CI, 39–142) and 80 (95% CI, 38–127) PTNB procedures were required to achieve acceptable diagnostic performance and pneumothorax occurrence, respectively.ConclusionThe novice operators' skills in performing CBCT virtual navigation-guided PTNBs improved with increasing experience over a wide range of learning periods.

Diluted Contrast-enhanced Cone-beam CT during Acute-phase Recanalization Therapy for Occlusion of the Middle Cerebral Artery

Objective: We here report the methods for and efficacy of C-arm cone-beam CT (CBCT) with diluted contrast medium during the recanalization therapy in acute ischemic stroke patients with middle cerebral artery occlusion.

ESTIMATION OF PATIENT LENS DOSE ASSOCIATED WITH C-ARM CONE-BEAM COMPUTED TOMOGRAPHY USAGE DURING INTERVENTIONAL NEURORADIOLOGY.

The purpose of this study was to investigate the dose distribution and lens doses associated with C-arm cone-beam computed tomography (CBCT), using a head phantom, and to estimate the contribution ratio of C-arm CBCT to each patient's lens dose during interventional neuroradiology ('lens dose ratio') in 109 clinical cases. In the phantom study, the peak skin doses and respective right and left lens doses of C-arm CBCT were as follows: 63.0 ± 1.9 mGy, 19.7 ± 1.4 mGy and 21.9 ± 0.8 mGy in whole brain C-arm CBCT and 39.2 ± 1.4 mGy, 4.7 ± 0.9 mGy and 3.6 ± 0.3 mGy in high-resolution C-arm CBCT. In the clinical study, the lens dose ratios were 25.4 ± 8.7% in the right lens and 19.1 ± 9.8% in the left lens. This study shows that, on average, ~25% of patients' total lens dose was contributed by C-arm CBCT.

The occurrence of neointimal hyperplasia after flow-diverter implantation is associated with cardiovascular risks factors and the stent design

BackgroundNeo-intimal hyperplasia (NIH) is frequently observed after flow-diverter stent (FDS) implantation. Although mostly asymptomatic, this vascular response can sometimes lead to delayed ischemic strokes. This study intended to evaluate the...

A Novel Technique in the Treatment of Lymphoceles After Renal Transplantation: C-Arm Cone Beam CT-Guided Percutaneous Embolization of Lymphatic Leakage After Lymphangiography.

We aimed to evaluate the efficacy of percutaneous embolization after lymphangiography using C-arm cone-beam computed tomography (CBCT) performed at the site of lymphatic leakage in patients with postrenal transplant lymphocele. Between July 2014 and August 2017, 13 patients not responding to percutaneous ethanol sclerotherapy and conservative treatment for recurrent lymphocele after renal transplant were included. The mean age of the patients was 56.38 ± 9.91 (range, 36-70) years, and it comprised 9 men and 4 women. All patients underwent intranodal lymphangiography. C-arm CBCT-guided percutaneous embolization was performed in patients with confirmed lymphatic leakage. Patients who had no lymphatic leakage underwent drainage with fibrin glue injection. Lymphatic leakage was observed in 9 patients after lymphangiography, and they underwent CBCT-guided percutaneous N-butyl-2-cyanoacrylate embolization. The volume of lymphatic drainage reduced to less than 10 mL in 8 patients. One patient who was not responding to embolization was treated surgically, after percutaneous drainage and fibrin glue injection. Lymphatic leakage was not observed in 4 patients after lymphangiography. Of these, 3 patients showed a reduction in the amount of lymphatic drainage after lymphangiography. All 4 patients underwent percutaneous drainage and fibrin glue injection. One patient did not respond to the treatment and was treated surgically. Prelymphangiography and postlymphangiography and embolization, the volume of lymphatic drainage was 113.07 ± 21.75 mL, and 53.84 ± 30.96 mL, respectively, and statistically significant decrease was detected (P < 0.005). Lymphangiography and CBCT-guided percutaneous embolization procedures might be an effective treatment method for patients with lymphocele refractory to treatment.

A Stitch in Time Saves 1.9 Million: How Advanced Imaging Solutions in Neuroradiology can Improve Outcomes for Stroke Patients

Stroke is the leading cause of disability in Canada and the third leading cause of death. Every year there are over 50,000 new strokes, with nearly 14,000 of cases resulting in death. For every minute delay in treating a stroke, the patient loses 1.9 million brain cells, and for each hour in which treatment does not occur, the brain loses as many neurons as it does in almost 3.6 years of normal aging. Thus, it is vital that the patient receives revascularization therapy as soon as possible. Despite this knowledge, there is still an inefficient use of time between stroke onset to revascularization. Advanced image solutions are urgently needed to shorten the door to treatment time, save more brain cells and improve patient outcomes. Currently, the stroke team relies on CT to detect blood, ischemia, occlusion or stenosis and assess brain tissue at risk. This step in the workflow can delay revascularization therapy by up to 60 minutes. Our multidisciplinary research team is working with a vendor engineering team to 1) improve the image quality of the Philips Allura c-arm cone-beam CT (XperCT) and 2) develop specialized stroke imaging software. The goal is to improve the imaging capabilities of the angiography suite so that it can provide the same essential imaging as standard CT, allowing patients to forgo a visit to CT and go straight to the angio-suite for treatment, shortening the door to puncture time by up to 60 minutes. Thus far, we have improved the image quality of cone-beam CT by utilizing a specialized aluminum filter and reconstruction algorithms designed to reduce bone-beam hardening effects. Our current stroke imaging protocol consists of the standard non-enhanced XperCT ‘mask’ image, followed by a unique dual-phase enhanced XperCT. The dual-phase scan consists of two modified XperCT acquisitions with the c-arm performing a propeller scan 220 degrees in each direction around the patient’s head during IV injection of a contrast bolus (80 cc). The scans are 10 seconds apart, and result in volumetric images of early and late brain perfusion phases. The specialized stroke analysis software then performs a subtraction of these two phases to highlight any brain regions of delayed filling. Using a quality assessment questionnaire, the unenhanced and perfusion XperCT scans acquired in the angio-suite were evaluated by an experienced radiologist and compared to unenhanced and perfusion images acquired in CT. Results demonstrated that the image quality improvements and new stroke imaging software can provide the necessary diagnostic information, in the angio-suite, immediately before revascularization therapy. This includes the detection or exclusion of blood, ischemia, occlusion or stenosis and tissue at risk. Limitations with this process do exist. For example, patient motion between the scans can interfere with the subtraction process. Additionally, although the cone-beam CT images are sufficient for diagnosis, the XperCT quality still has inferior contrast and spatial resolution compared to a standard CT perfusion. Currently, stroke patients must first visit the CT department for imaging to confirm a large vessel occlusion before going to the angiography suite for mechanical thromectomy treatment. Preliminary results from our efforts to improve cone-beam CT image quality and develop specialized stroke image analysis software demonstrate that diagnostic-quality imaging can be acquired using a c-arm in the angio-suite, allowing patients to bypass CT and come straight to the angio-suite for imaging and immediate treatment. Although image quality improvement work continues, this one-stop-stroke-shop approach promises to reduce diagnosis time, save more brain cells and improve patient outcomes.

A novel technique of cervical pedicle screw placement with a pilot screw under the guidance of intraoperative 3D imaging from C-arm cone-beam CT without navigation for safe and accurate insertion.

The cervical pedicle screw (CPS) requires careful and accurate placement because of the critical risk for neurovascular injury. This study aimed to introduce and evaluate the safety and efficacy of a new CPS placement technique using intraoperative C-arm cone-beam CT (CBCT) and a pilot screw without navigation system. This was a case-control study to compare the accuracy and safety of intraoperative C-arm CBCT-guided CPS placement with freehand CPS placement under lateral fluoroscopy using control data from a previous multicenter study. A total of 166 CPSs were inserted under intraoperative C-arm CBCT guidance in 48 consecutive patients (20 rheumatoid arthritis, 16 degenerative spinal disorders, 6 spinal tumor, 2 congenital deformity, 2 ossification of posterior longitudinal ligament, and 2 fracture dislocation). Accuracy and safety of CPS placement were assessed. The overall malposition rate was 2.4% (4 screws in grade 1: malposition by less than half-screw diameter, 0 in grade 2: malposition by more than half-screw diameter), which was significantly lower than the reported malposition rate of 14.8% in lateral fluoroscopy-guided freehand placement. There were no complications directly related to CPS insertion. The average estimated effective radiation dose per surgery was 14.7mSv. The novel technique enables intraoperative adjustment of the trajectory of the CPS as well as confirmation of the CPS path before penetrating the isthmus of the pedicle, resulting in accurate and safe CPS placement, which outweighs the demerits of radiation exposure. These slides can be retrieved under Electronic Supplementary Material.

3D C-Arm cone beam CT for targeting the portal vein during TIPS: Initial clinical experience

PurposeTo evaluate the feasibility, safety and usefulness of 3D CBCT with a new injection protocol for targeting the portal vein during TIPS and to determine if it allows decreasing the duration of the procedure. Materials and methods3D CBCT was obtained during creation of TIPS in 15 patients (group 2). Portogram quality score was defined using a 5 points scale. The time required to achieve portal puncture was also recorded and results were compared retrospectively in 15 patients who underwent TIPS without 3D CBCT (group 1). ResultsThe mean time required to puncture the portal vein was shorter when CBCT was used: 15 min versus 24 min (p = 0.156). We recorded 3 failures requiring a second procedure in group 1. There were no complications and no failure in group 2. We recorded 93% of good portography and 80% of good 3D roadmaps. Conclusion3D CBCT coupled with this new injection protocol provided high rate of good quality portography allowing to bring positional and directional information to improve the needle pass efficiency and to decrease the duration of the procedure.

Unique percutaneous direct puncture technique for occlusion of a hypoglossal canal dural arteriovenous fistula

PurposeTo report percutaneous transcranial puncture, embolization and occlusion of a very symptomatic hypoglossal canal/anterior condylar vein dural arteriovenous fistula (DAVF) using syngo iGuide navigational software in a patient in whom...

GPU based parallel acceleration for fast C-arm cone-beam CT reconstruction

BackgroundWith the introduction of Flat Panel Detector technology, cone-beam CT (CBCT) has become a novel image modality, and widely applied in clinical practices. C-arm mounted CBCT has shown extra suitability in image guided interventional surgeries. During practice, how to acquire high resolution and high quality 3D images with the real time requirement of clinical applications remain challenging.MethodsIn this paper, we propose a GPU based accelerated method for fast C-arm CBCT 3D image reconstructions. A filtered back projection method is optimized and implemented with GPU parallel acceleration technique. A distributed system is designed to make full use of the image acquisition consumption to hide the reconstruction delay to further improve system performance.ResultsWith the acceleration both in algorithm and system design, we show that our method significantly increases system efficiency. The optimized GPU accelerated FDK algorithm improves the reconstruction efficiency. The system performance is further enhanced with the proposed system design by 26% and reconstruction delay is accelerated by 2.1 times when 90 frames of projections are used. When the number of frames used increases to 120, the numbers are 39% and 3.3 times. We also show that when the projection acquisition consumption increases, the reconstruction acceleration rate increases significantly.

Combined cone beam computed tomography and fluoroscopy techniques for challenging percutaneous spine procedures

Transpedicular approaches for spine procedures are currently employed in biopsies and vertebroplasties (VT), and frequently performed with computed tomography (CT) or fluoroscopy for image guidance. The fluoroscopy is not always reliable in terms of visualization if the pedicle is very small or destroyed by osteolytic lesions. CT is more precise in these situations but needle progression is not visualized in dynamic view. We describe 3 cases where the anatomic landmarks were not well visualized in normal fluoroscopy and transpedicular needle implantation was achieved with a combined C-arm cone beam CT acquisition (CBCT), known as XperCT, and fluoroscopic overlay guidance, namely XperGuide.

Reduction of Angularly-Varying-Data Truncation in C-Arm CBCT Imaging.

C-arm cone-beam computed tomography (CBCT) has been used increasingly as an imaging tool for yielding 3D anatomical information about the subjects in surgical and interventional procedures. In the clinical applications, the limited field-of-view (FOV) of C-arm CBCT can lead to significant data truncation, resulting in image artifacts that can obscure low contrast tumor embedded within soft-tissue background, thus limiting the utility of C-arm CBCT. The truncation issue can become serious as most of the surgical and interventional procedures would involve devices and tubes that are placed outside the FOV of C-arm CBCT and thus can engender angularly-varying-data truncation. Existing methods may not be adequately applicable to dealing with the angularly-varying truncation. In this work, we seek to reduce truncation artifacts by tailoring optimization-based reconstruction directly from truncated data, without performing pre-reconstruction data compensation, collected from physical phantoms and human subjects. The reconstruction problem is formulated as a constrained optimization program in which a data-derivative-ℓ2-norm fidelity is included for effectively suppressing image artifacts caused by the angularly-varying-data truncation, and the generic Chambolle-Pock algorithm is tailored to solve the optimization program. The results of the study suggest that an appropriately designed optimization-based reconstruction can be exploited for yielding images with reduced artifacts caused by angularly-varying-data truncation.

Time-resolved C-arm cone beam CT angiography (TR-CBCTA) imaging from a single short-scan C-arm cone beam CT acquisition with intra-arterial contrast injection

Time-resolved C-arm cone-beam CT (CBCT) angiography (TR-CBCTA) images can be generated from a series of CBCT acquisitions that satisfy data sufficiency condition in analytical image reconstruction theory. In this work, a new technique was developed to generate TR-CBCTA images from a single short-scan CBCT data acquisition with contrast media injection. The reconstruction technique enabling this application is a previously developed image reconstruction technique, synchronized multi-artifact reduction with tomographic reconstruction (SMART-RECON). In this new application, the acquired short-scan CBCT projection data were sorted into a union of several sub-sectors of view angles and each sub-sector of view angles corresponds to an individual image volume to be reconstructed. The SMART-RECON method was then used to jointly reconstruct all of these individual image volumes under two constraints: (1) each individual image volume is maximally consistent with the measured cone-beam projection data within the corresponding view angle sector and (2) the nuclear norm of the image matrix is minimized. The difference between these reconstructed individual image volumes is used to generated the desired subtracted angiograms. To validate the technique, numerical simulation data generated from a fractal tree angiogram phantom were used to quantitatively study the accuracy of the proposed method and retrospective in vivo human subject studies were used to demonstrate the feasibility of generating TR-CBCTA in clinical practice.

3D Deep Learning Angiography (3D-DLA) from C-arm Conebeam CT.

Deep learning is a branch of artificial intelligence that has demonstrated unprecedented performance in many medical imaging applications. Our purpose was to develop a deep learning angiography method to generate 3D cerebral angiograms from a single contrast-enhanced C-arm conebeam CT acquisition in order to reduce image artifacts and radiation dose. A set of 105 3D rotational angiography examinations were randomly selected from an internal data base. All were acquired using a clinical system in conjunction with a standard injection protocol. More than 150 million labeled voxels from 35 subjects were used for training. A deep convolutional neural network was trained to classify each image voxel into 3 tissue types (vasculature, bone, and soft tissue). The trained deep learning angiography model was then applied for tissue classification into a validation cohort of 8 subjects and a final testing cohort of the remaining 62 subjects. The final vasculature tissue class was used to generate the 3D deep learning angiography images. To quantify the generalization error of the trained model, we calculated the accuracy, sensitivity, precision, and Dice similarity coefficients for vasculature classification in relevant anatomy. The 3D deep learning angiography and clinical 3D rotational angiography images were subjected to a qualitative assessment for the presence of intersweep motion artifacts. Vasculature classification accuracy and 95% CI in the testing dataset were 98.7% (98.3%-99.1%). No residual signal from osseous structures was observed for any 3D deep learning angiography testing cases except for small regions in the otic capsule and nasal cavity compared with 37% (23/62) of the 3D rotational angiographies. Deep learning angiography accurately recreated the vascular anatomy of the 3D rotational angiography reconstructions without a mask. Deep learning angiography reduced misregistration artifacts induced by intersweep motion, and it reduced radiation exposure required to obtain clinically useful 3D rotational angiography.

Effect of metal artifact reduction software on image quality of C-arm cone-beam computed tomography during intracranial aneurysm treatment.

Background and purpose C-arm cone-beam computed tomography (CBCT) has the drawback that image quality is degraded by artifacts caused by implanted metal objects. We evaluated whether metal artifact reduction (MAR) prototype software can improve the subjective image quality of CBCT images of patients with intracranial aneurysms treated with coils or clips. Materials and methods Forty-four patients with intracranial aneurysms implanted with coils (40 patients) or clips (four patients) underwent one CBCT scan from which uncorrected and MAR-corrected CBCT image datasets were reconstructed. Three blinded readers evaluated the image quality of the image sets using a four-point scale (1: Excellent, 2: Good, 3: Poor, 4: Bad). The median scores of the three readers of uncorrected and MAR-corrected images were compared with the paired Wilcoxon signed-rank and inter-reader agreement of change scores was assessed by weighted kappa statistics. The readers also recorded new clinical findings, such as intracranial hemorrhage, air, or surrounding anatomical structures on MAR-corrected images. Results The image quality of MAR-corrected CBCT images was significantly improved compared with the uncorrected CBCT image ( p < 0.001). Additional clinical findings were seen on CBCT images of 70.4% of patients after MAR correction. Conclusion MAR software improved image quality of CBCT images degraded by metal artifacts.

Investigations of organ and effective doses of abdominal cone-beam computed tomography during transarterial chemoembolization using Monte Carlo simulation

BackgroundTo investigate the organ dose, effective dose (ED), conversion factor, and the C-arm rotation angle effects on dose variations of abdominal C-arm cone-beam computed tomography (CBCT) during transarterial chemoembolization (TACE).MethodsThe organ doses and EDs for abdominal C-arm CBCT were retrospectively calculated according to a Monte Carlo technique for 80 patients. Dose variations from projections, ED to dose–area product (DAP) ratios, and effects of body mass index (BMI) on the ED and ED to DAP ratios were also analyzed.ResultsThe kidney received the highest dose (14.6 ± 1.2 mSv). Organ dose deviations among C-arm rotation angles was highest for stomach (CV = 0.71). The mean ED of the the CBCT run during TACE was 3.5 ± 0.5 mSv, and decreased with increased BMI (R2 = 0.45, p < 0.001). The mean ED to DAP ratio was 0.27 ± 0.04 mSv·Gy− 1·cm− 2 and tended to decrease with increased BMI (R2 = 0.55, p < 0.001). The mean ED to DAP ratios were 0.29 ± 0.02, 0.26 ± 0.02, and 0.23 ± 0.03 mSv·Gy− 1·cm− 2 for patients with BMI < 25 kg/m2, 25–30 kg/m2, and ≥30 kg/m2, respectively.ConclusionsSuitable conversion factors for C-arm CBCT facilitate the use of DAPs for estimating the ED. The patient dose can be varied by adjusting the CBCT rotation angle setting, and dose reduction strategies can be further manipulated.

A Systematic Review and Meta-Analysis of C-Arm Cone-Beam CT-Guided Percutaneous Transthoracic Needle Biopsy of Lung Nodules.

SummaryBackgroundA systematic review and meta-analysis of all available publications was performed to evaluate the diagnostic accuracy of percutaneous transthoracic needle biopsy (PTNB) using a C-Arm Cone-Beam CT (CBCT) system in patients with lung nodules.Material/MethodsThedatabases of PUBMED, OVID, EBSCO, EMBASE, and China National Knowledge Infrastructure (CNKI) were systematically searched for relevant original articles on the diagnostic accuracy of CBCT-guided PTNB for the diagnosis of nodules in the lungs. Diagnostic indices including sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR) and diagnostic score (DS) were calculated. Moreover,summary receiver operating characteristic curves (SROC) were constructed with Stata (version 13.0), Rev Man (version 5.3), and Meta-disc (version 1.4) software. Other clinical indices such as incidence of complications were also recorded.ResultsEight studies met the inclusion and exclusion criteria for the meta-analysis. The pooled sensitivity, specificity, PLR, NLR, DOR, DS, and SROC with 95% confidence intervals were 0.96 (0.93–0.98), 1.00 (0.91–1.00), 711.15 (9.48–53325.89), 0.04 (0.02–0.07), 16585.29 (284.88–9.7e+05), 9.72 (5.65–13.78), and 0.99 (0.97–0.99), respectively. The incidence of pneumothorax and hemorrhage was 10–29.27% and 1.22–47.25%, respectively.ConclusionsCBCT-guided PTNB has an acceptable rate of complications and is associated with a reasonable radiation exposure. Moreover, it is a highly accurate and safe technique for the diagnosis of lung nodules and can be recommended to be used in routine clinical practice.