Publications by authors named "Quirina M B de Ruiter"

13 Publications

  • Page 1 of 1

Radiation Awareness for Endovascular Abdominal Aortic Aneurysm Repair in the Hybrid Operating Room: An Instant Operator Risk Chart for Daily Practice.

J Endovasc Ther 2021 Apr 14:15266028211007458. Epub 2021 Apr 14.

Department of Vascular Surgery, University Medical Center Utrecht, The Netherlands.

Introduction: While the operator radiation dose rates are correlated to patient radiation dose rates, discrepancies may exist in the effect size of each individual radiation dose predictors. An operator dose rate prediction model was developed, compared with the patient dose rate prediction model, and converted to an instant operator risk chart.

Materials And Methods: The radiation dose rates (DR for the operator and DR for the patient) from 12,865 abdomen X-ray acquisitions were selected from 50 unique patients undergoing standard or complex endovascular aortic repair (EVAR) in the hybrid operating room with a fixed C-arm. The radiation dose rates were analyzed using a log-linear multivariable mixed model (with the patient as the random effect) and incorporated varying (patient and C-arm) radiation dose predictors combined with the vascular access site. The operator dose rate models were used to predict the expected radiation exposure duration until an operator may be at risk to reach the 20 mSv year dose limit. The dose rate prediction models were translated into an instant operator radiation risk chart.

Results: In the multivariate patient and operator fluoroscopy dose rate models, lower DR than DR effect size was found for radiation protocol (2.06 for patient vs 1.4 for operator changing from low to medium protocol) and C-arm angulation. Comparable effect sizes for both DR and DR were found for body mass index (1.25 for patient and 1.27 for the operator) and irradiated field. A higher effect size for the DR than DR was found for C-arm rotation (1.24 for the patient vs 1.69 for the operator) and exchanging from femoral access site to brachial access (1.05 for patient vs 2.5 for the operator). Operators may reach their yearly 20 mSv year dose limit after 941 minutes from the femoral access vs 358 minutes of digital subtraction angiography radiation from the brachial access.

Conclusion: The operator dose rates were correlated to patient dose rate; however, C-arm angulation and changing from femoral to brachial vascular access site may disproportionally increase the operator radiation risk compared with the patient radiation risk. An instant risk chart may improve operator dose awareness during EVAR.
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http://dx.doi.org/10.1177/15266028211007458DOI Listing
April 2021

Synthesis, characterization, and imaging of radiopaque bismuth beads for image-guided transarterial embolization.

Sci Rep 2021 Jan 12;11(1):533. Epub 2021 Jan 12.

Center for Interventional Oncology, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, USA.

Current therapy for hypervascular cancers, e.g., hepatocellular carcinoma, includes occlusion of the tumor blood supply by arterial infusion of embolic microspheres (beads) suspended in iodine-based contrast under fluoroscopic guidance. Available radiopaque, imageable beads use iodine as the radiopacifier and cannot be differentiated from contrast. This study aimed to synthesize and characterize imageable beads using bismuth as the radiopacifier that could be distinguished from iodine contrast based upon the difference in the binding energy of k-shell electrons (k-edge). Radiodense bismuth beads were successfully synthesized some with uniform bismuth distribution across the beads. The beads were spherical and could be infused through clinical microcatheters. The bismuth beads could be imaged with clinical dual-energy computed tomography (CT), where iodine-based contrast could be distinguished from the microspheres. The ability to separate iodine from bismuth may enhance the diagnostic information acquired on follow-up CT, identifying the distribution of the embolic beads separately from the contrast. Furthermore, with sequential use of iodine- and bismuth-based beads, the two radiopaque beads could be spatially distinguished on imaging, which may enable the development of dual drug delivery and dual tracking.
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http://dx.doi.org/10.1038/s41598-020-79900-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7804415PMC
January 2021

Comparison of Smartphone Augmented Reality, Smartglasses Augmented Reality, and 3D CBCT-guided Fluoroscopy Navigation for Percutaneous Needle Insertion: A Phantom Study.

Cardiovasc Intervent Radiol 2021 May 6;44(5):774-781. Epub 2021 Jan 6.

Center for Interventional Oncology, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, 20892, USA.

Purpose: To compare needle placement performance using an augmented reality (AR) navigation platform implemented on smartphone or smartglasses devices to that of CBCT-guided fluoroscopy in a phantom.

Materials And Methods: An AR application was developed to display a planned percutaneous needle trajectory on the smartphone (iPhone7) and smartglasses (HoloLens1) devices in real time. Two AR-guided needle placement systems and CBCT-guided fluoroscopy with navigation software (XperGuide, Philips) were compared using an anthropomorphic phantom (CIRS, Norfolk, VA). Six interventional radiologists each performed 18 independent needle placements using smartphone (n = 6), smartglasses (n = 6), and XperGuide (n = 6) guidance. Placement error was defined as the distance from the needle tip to the target center. Placement time was recorded. For XperGuide, dose-area product (DAP, mGy*cm) and fluoroscopy time (sec) were recorded. Statistical comparisons were made using a two-way repeated measures ANOVA.

Results: The placement error using the smartphone, smartglasses, or XperGuide was similar (3.98 ± 1.68 mm, 5.18 ± 3.84 mm, 4.13 ± 2.38 mm, respectively, p = 0.11). Compared to CBCT-guided fluoroscopy, the smartphone and smartglasses reduced placement time by 38% (p = 0.02) and 55% (p = 0.001), respectively. The DAP for insertion using XperGuide was 3086 ± 2920 mGy*cm, and no intra-procedural radiation was required for augmented reality.

Conclusions: Smartphone- and smartglasses-based augmented reality reduced needle placement time and radiation exposure while maintaining placement accuracy compared to a clinically validated needle navigation platform.
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http://dx.doi.org/10.1007/s00270-020-02760-7DOI Listing
May 2021

Feasibility of fresh frozen human cadavers as a research and training model for endovascular image guided interventions.

PLoS One 2020 30;15(11):e0242596. Epub 2020 Nov 30.

Department of Surgery, University Medical Center Utrecht, Utrecht, The Netherlands.

Objective: To describe the feasibility of a fresh frozen human cadaver model for research and training of endovascular image guided procedures in the aorta and lower extremity.

Methods: The cadaver model was constructed in fresh frozen human cadaver torsos and lower extremities. Endovascular access was acquired by inserting a sheath in the femoral artery. The arterial segment of the specimen was restricted by ligation of collateral arteries and, in the torsos, clamping of the contralateral femoral artery and balloon occlusion of the supratruncal aorta. Tap water was administered through the sheath to create sufficient intraluminal pressure to manipulate devices and acquire digital subtraction angiography (DSA). Endovascular cannulation tasks of the visceral arteries (torso) or the peripheral arteries (lower extremities) were performed to assess the vascular patency of the model. Feasibility of this model is based on our institute's experiences throughout the use of six fresh frozen human cadaver torsos and 22 lower extremities.

Results: Endovascular simulation in the aortic and peripheral vasculature was achieved using this human cadaver model. Acquisition of DSA images was feasible in both the torsos and the lower extremities. Approximately 84 of the 90 target vessels (93.3%) were patent, the remaining six vessels showed signs of calcified steno-occlusive disease.

Conclusions: Fresh frozen human cadavers provide a feasible simulation model for aortic and peripheral endovascular interventions, and can potentially reduce the need for animal experimentation. This model is suitable for the evaluation of new endovascular devices and techniques or to master endovascular skills.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0242596PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7704126PMC
January 2021

Endobronchial Navigation Guided by Cone-Beam CT-Based Augmented Fluoroscopy without a Bronchoscope: Feasibility Study in Phantom and Swine.

J Vasc Interv Radiol 2020 Dec 2;31(12):2122-2131. Epub 2020 Oct 2.

Center for Interventional Oncology, Radiology & Imaging Sciences, National Institutes of Health Clinical Center, MSC 1182, Bldg. 10, Room 1C341, Bethesda, MD, 20892.

Purpose: To evaluate the accuracy of cone-beam computed tomography (CT)-based augmented fluoroscopy (AF) image guidance for endobronchial navigation to peripheral lung targets.

Methods: Prototypic endobronchial navigation AF software that superimposed segmented airways, targets, and pathways based on cone-beam CT onto fluoroscopy images was evaluated ex vivo in fixed swine lungs and in vivo in healthy swine (n = 4) without a bronchoscope. Ex vivo and in vivo (n = 3) phase 1 experiments used guide catheters and AF software version 1, whereas in vivo phase 2 (n = 1) experiments also used an endovascular steerable guiding sheath, upgraded AF software version 2, and lung-specific low-radiation-dose protocols. First-pass navigation success was defined as catheter delivery into a targeted airway segment solely using AF, with second-pass success defined as reaching the targeted segment by using updated AF image guidance based on confirmatory cone-beam CT. Secondary outcomes were navigation error, navigation time, radiation exposure, and preliminary safety.

Results: First-pass success was 100% (10/10) ex vivo and 19/24 (79%) and 11/15 (73%) for in vivo phases 1 and 2, respectively. Phase 2 second-pass success was 4/4 (100%). Navigation errors were 2.2 ± 1.2 mm ex vivo and 4.9 ± 3.2 mm and 4.0 ± 2.6 mm for in vivo phases 1 and 2, respectively. No major device-related complications were observed in the in vivo experiments.

Conclusions: Endobronchial navigation is feasible and accurate with cone-beam CT-based AF image guidance. AF can guide endobronchial navigation with endovascular catheters and steerable guiding sheaths to peripheral lung targets, potentially overcoming limitations associated with bronchoscopy.
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http://dx.doi.org/10.1016/j.jvir.2020.04.036DOI Listing
December 2020

Smartphone Augmented Reality CT-Based Platform for Needle Insertion Guidance: A Phantom Study.

Cardiovasc Intervent Radiol 2020 May 8;43(5):756-764. Epub 2020 Jan 8.

Center for Interventional Oncology, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, 20892, USA.

Objective: To develop and assess the accuracy of an augmented reality (AR) needle guidance smartphone application.

Methods: A needle guidance AR smartphone application was developed using Unity and Vuforia SDK platforms, enabling real-time displays of planned and actual needle trajectories. To assess the application's accuracy in a phantom, eleven operators (including interventional radiologists, non-interventional radiology physicians, and non-physicians) performed single-pass needle insertions using AR guidance (n = 8) and CT-guided freehand (n = 8). Placement errors were measured on post-placement CT scans. Two interventional radiologists then used AR guidance (n = 3) and CT-guided freehand (n = 3) to navigate needles to within 5 mm of targets with intermediate CT scans permitted to mimic clinical use. The total time and number of intermediate CT scans required for successful navigation were recorded.

Results: In the first experiment, the average operator insertion error for AR-guided needles was 78% less than that for CT-guided freehand (2.69 ± 2.61 mm vs. 12.51 ± 8.39 mm, respectively, p < 0.001). In the task-based experiment, interventional radiologists achieved successful needle insertions on each first attempt when using AR guidance, thereby eliminating the need for intraoperative CT scans. This contrasted with 2 ± 0.9 intermediate CT scans when using CT-guided freehand. Additionally, average procedural times were reduced from 13.1 ± 6.6 min with CT-guided freehand to 4.5 ± 1.3 min with AR guidance, reflecting a 66% reduction.

Conclusions: All operators exhibited superior needle insertion accuracy when using the smartphone-based AR guidance application compared to CT-guided freehand. This AR platform can potentially facilitate percutaneous biopsies and ablations by improving needle insertion accuracy, expediting procedural times, and reducing radiation exposures.
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http://dx.doi.org/10.1007/s00270-019-02403-6DOI Listing
May 2020

Procedure and step-based analysis of the occupational radiation dose during endovascular aneurysm repair in the hybrid operating room.

J Vasc Surg 2018 06;67(6):1881-1890

Department of Vascular Surgery, University Medical Center Utrecht, Utrecht, The Netherlands. Electronic address:

Objective: This study measured the cumulative occupational X-ray radiation dose received by support staff during endovascular aortic procedures and during additional intraoperative steps in the hybrid operating room.

Methods: Radiation dose measurements were performed during interventions on 65 patients receiving 90 stent grafts during endovascular aneurysm repair (EVAR), bifurcated EVAR, thoracic EVAR, iliac branched device deployment, aortouni-iliac stenting, and fenestrated/branched EVAR (F/BrEVAR). X-ray imaging was acquired using the Philips Allura FD20 Clarity System (Philips Medical Systems, Best, The Netherlands). The occupational radiation dose (also referred to as the estimated effective dose, E, measured in millisieverts) was measured with the DoseAware Xtend system (Philips Medical Systems) personal dosimeters. E was reported per staff member (E), where "staff" was a generic term for each staff member included in the study: the first operator (FO), the second operator (ESO), a virtual maximum operator (MO), and all additional supporting staff, including the sterile nurse, nonsterile nurse, anaesthesiologist, and radiation technician. The primary outcome was the median cumulative E (or E, E, and so on), which was presented as the median cumulative dose per intervention and stratified for several within-interventional EVAR and F/BrEVAR steps or stents. The second outcome was the percentage of the absorbed E by a supporting staff member in relation to the E measured by the reference badge attached on the C-arm (E or E, E, and so on). All outcomes are presented as median with interquartile range, unless stated differently.

Results: The occupational effective dose in millisieverts of the MO (E) was 0.055 (0.029-0.082) for aortouni-iliac stenting (n = 6), 0.084 (0.054-0.141) during thoracic EVAR (n = 14), 0.036 (0.026-0.068) during bifurcated EVAR (n = 38), 0.054 (0.035-0.126) during iliac branched device deployment (n = 8), and 0.345 (0.235-0.757) during F/BrEVAR (n = 24). The median E in millisieverts was 0.025 (0.012-0.062) per renal target vessel (TV) and 0.146 (0.07-0.315) for a nonrenal visceral TV. During all noncomplex interventions, the E was 4.4% (2.7%-7.3%), with the lowest median rate at 3.5% (2.5%-5%) for EVAR. The highest median rate E was found for F/BrEVAR procedures: 8.2% (5.0%-14.4%).

Conclusions: With maximum operator shielding during femoral access, relative occupational radiation risk can be minimized. However, digital subtraction angiography image acquisition, recanalization of TVs, recanalization of superior mesenteric artery or celiac artery, and recanalization of branched TVs are predictors for increased occupational radiation dose risks caused by increased radiation doses to the patient and reduced options for shielding of the operator.
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http://dx.doi.org/10.1016/j.jvs.2017.09.043DOI Listing
June 2018

Midterm outcomes and evolution of gutter area after endovascular aneurysm repair with the chimney graft procedure.

J Vasc Surg 2018 01 28;67(1):104-112.e3. Epub 2017 Jun 28.

Department of Vascular Surgery, University Medical Center, Utrecht, The Netherlands. Electronic address:

Objective: The objective of this study was to describe our experience with endovascular aneurysm repair (EVAR) with the use of chimney grafts for branch vessel preservation.

Methods: Patients treated with a chimney graft procedure between October 2009 and May 2015 were included for analysis. Patients who were not considered eligible for open surgical repair or for conventional, branched, or fenestrated endovascular repair were selected. A standardized operating procedure with left brachial or axillary artery cutdown access for the chimney grafts and bilateral femoral artery cutdown access for the aortic main device was used. Outcomes were noted according to the Society for Vascular Surgery reporting standards. In addition, evolution of gutter area over time was determined. Estimated rates of survival, freedom from aneurysm growth, and clinical success at 24 months of follow-up were calculated.

Results: Thirty-three patients (mean age, 77.6 ± 6.8 years; 87.9% male) with a mean preoperative maximum aneurysm diameter of 71.7 ± 13.5 mm were included. A total of 54 of an intended 54 chimney grafts were deployed. Primary technical success and 30-day secondary clinical success rates were 87.9% and 84.8%, respectively. The early mortality rate was 6.1% (n = 2). The early type IA endoleak rate was 6.1% (n = 2), and the chimney graft occlusion rate was 6.1% (n = 2). Median follow-up duration was 26 months (interquartile range, 14.8-37.3 months). The estimated 2-year actuarial survival rate was 78.1% (standard error, ±7.4%). Late complications included type IA endoleak (n = 1), chimney graft occlusion (n = 2), type II endoleak with aneurysm growth (n = 4), and distal stent graft limb kinking and occlusion (n = 1). Late reinterventions included coil or glue embolization (n = 3), distal limb extension (n = 2), open endoleak ligation (n = 2), Palmaz stent placement (n = 1), repeated EVAR (n = 1), and femorofemoral bypass graft (n = 1). At 2 years, the estimated secondary clinical success and freedom from aneurysm growth rates were 80.5% (±7.2%) and 84.4% (±7.2%). Gutter size showed a small but significant decrease over time at the level of the proximal markers and at 10 mm distal from the markers.

Conclusions: Midterm results show that a standardized procedure for EVAR using chimney grafts for branch vessel preservation is an acceptable option for high-risk patients with large, complex aneurysms who are unfit for open repair and who have been excluded from fenestrated EVAR. Gutter size decreases over time, but the rate of branch vessel loss and reinterventions demonstrate that this approach should remain reserved for those who are at truly prohibitive risk for open or fenestrated stent graft repair.
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http://dx.doi.org/10.1016/j.jvs.2017.04.067DOI Listing
January 2018

Meta-analysis of Cumulative Radiation Duration and Dose During EVAR Using Mobile, Fixed, or Fixed/3D Fusion C-Arms.

J Endovasc Ther 2016 12 8;23(6):944-956. Epub 2016 Sep 8.

Department of Vascular Surgery, University Medical Center Utrecht, the Netherlands.

Purpose: To investigate the total fluoroscopy time and radiation exposure dose during endovascular aortic repairs using mobile, fixed, or fixed C-arms with 3-dimensional image fusion (3D-IF).

Methods: A systematic search was performed to identify original articles reporting fluoroscopy time (FT) and the kerma area product (KAP) during endovascular aortic repairs. Data were grouped by noncomplex or complex (fenestrated, branched, or chimney) repairs and stratified by type of C-arm. The search identified 27 articles containing 51 study groups (35 noncomplex and 16 complex) that included 3444 patients. Random-effects meta-analysis and meta-regression models were used to calculate the pooled mean estimates of KAP and FT, as well as any effect of equipment or type of intervention. Results are presented with the 95% confidence interval and the statistical heterogeneity (I).

Results: Within the noncomplex procedure studies, a significant (p<0.001) increase was found in the pooled mean KAP estimate in the fixed C-arm group (181 Gy·cm, 95% CI 129 to 233; I=99.7) compared with the mobile C-arm (78 Gy·cm, 95% CI 59.6 to 97.3; I=99.6). For complex cases, use of 3D-IF showed a significantly (p<0.001) lower mean KAP (139 Gy·cm, 95% CI 85 to 191; I=94%) compared to using fixed C-arms without 3D-IF (487 Gy·cm, 95% CI 331 to 643; I=94%).

Conclusion: For equivalent fluoroscopy times, the use of a fixed C-arm in noncomplex procedures leads to higher patient radiation doses compared to a mobile C-arm. Complex procedures, which are predominantly performed using fixed C-arms, are associated with the highest radiation dose per intervention. Using fixed C-arms combined with 3D-IF techniques during complex cases might seem an adequate method to compensate for the higher radiation doses measured when a fixed C-arm is used.
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http://dx.doi.org/10.1177/1526602816668305DOI Listing
December 2016

AlluraClarity Radiation Dose-Reduction Technology in the Hybrid Operating Room During Endovascular Aneurysm Repair.

J Endovasc Ther 2016 Feb;23(1):130-8

Department of Vascular Surgery, University Medical Center, Utrecht, the Netherlands.

Purpose: To evaluate the effect of radiation dose reduction with the Allura ClarityIQ image processing technology for fixed C-arms in comparison with a mobile C-arm and an Allura fixed C-arm without ClarityIQ technology during endovascular aneurysm repair (EVAR) procedures.

Methods: Radiation dose data from 85 patients (mean age 74.2±7.8 years; 68 men) undergoing EVAR with mobile and fixed C-arm fluoroscopy were retrospectively analyzed. The radiation dose parameters included the kerma area product (KAP), fluoroscopic time (FT), and number of digital subtraction angiography (DSA) frames (FrDSA). KAPtotal consisted of KAPfluoro (KAP for fluoroscopic imaging) and KAPDSA (KAP for DSA and single shots). Linear regression analysis was used to explore differences in the association of KAP with the FT, FrDSA, and body mass index (BMI) among the 3 C-arms.

Results: The mean KAPtotal values for mobile, Allura C-arm, and AlluraClarity C-arm for noncomplex EVARs were 56±39, 245±142, and 157±120 Gy·cm(2) (p<0.001); for complex EVARs, the values were 110±43, 874±653, and 598±319 Gy·cm(2) (p<0.001), respectively. On average, KAPfluoro tripled when the mobile C-arm was replaced by the fixed C-arm. There were no significant differences in the KAPfluoro adjusted for the FT between Allura and AlluraClarity (p=0.69). However, there was a major 61% reduction in KAPDSA from 1.36 Gy·cm(2) per DSA frame for Allura to 0.54 Gy·cm(2) per DSA frame with AlluraClarity (p=0.03). For the mobile C-arm, BMI was not associated with KAP (p=0.13). The associations of BMI with KAPfluoro and KAPDSA were significant for both fixed C-arms but were more robust for Allura compared to AlluraClarity (p=0.02 for KAPfluoro and p<0.001 for KAPDSA).

Conclusion: Changing a mobile C-arm for a fixed C-arm in a hybrid operating suite increased the average intraoperative dose during EVAR. Upgrading the Allura fixed C-arm with ClarityIQ technology resulted in a 61% reduction in the radiation per DSA frame.
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http://dx.doi.org/10.1177/1526602815622433DOI Listing
February 2016

Dose reduction with iterative reconstruction for coronary CT angiography: a systematic review and meta-analysis.

Br J Radiol 2016 12;89(1058):20150068. Epub 2015 Nov 12.

3 Department of Radiology, Erasmus Medical Center, Rotterdam, Netherlands.

Objective: To investigate the achievable radiation dose reduction for coronary CT angiography (CCTA) with iterative reconstruction (IR) in adults and the effects on image quality.

Methods: PubMed and EMBASE were searched, and original articles concerning IR for CCTA in adults using prospective electrocardiogram triggering were included. Primary outcome was the effective dose using filtered back projection (FBP) and IR. Secondary outcome was the effect of IR on objective and subjective image quality.

Results: The search yielded 1616 unique articles, of which 10 studies (1042 patients) were included. The pooled routine effective dose with FBP was 4.2 mSv [95% confidence interval (CI) 3.5-5.0]. A dose reduction of 48% to a pooled effective dose of 2.2 mSv (95% CI 1.3-3.1) using IR was reported. Noise, contrast-to-noise ratio and subjective image quality were equal or improved in all but one study, whereas signal-to-noise ratio was decreased in two studies with IR at reduced dose.

Conclusion: IR allows for CCTA acquisition with an effective dose of 2.2 mSv with preserved objective and subjective image quality.
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http://dx.doi.org/10.1259/bjr.20150068DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4985187PMC
May 2016

Achievable dose reduction using iterative reconstruction for chest computed tomography: A systematic review.

Eur J Radiol 2015 Nov 17;84(11):2307-13. Epub 2015 Jul 17.

Department of Radiology, Erasmus Medical Center, PO Box 2040, 3000CA Rotterdam, The Netherlands.

Objectives: Iterative reconstruction (IR) allows for dose reduction with maintained image quality in CT imaging. In this systematic review the reported effective dose reductions for chest CT and the effects on image quality are investigated.

Methods: A systematic search in PubMed and EMBASE was performed. Primary outcome was the reported local reference and reduced effective dose and secondary outcome was the image quality with IR. Both non contrast-enhanced and enhanced studies comparing reference dose with reduced dose were included.

Results: 24 studies were included. The median number of patients per study was 66 (range 23-200) with in total 1806 patients. The median reported local reference dose of contrast-enhanced chest CT with FBP was 2.6 (range 1.5-21.8) mSv. This decreased to 1.4 (range 0.4-7.3) mSv at reduced dose levels using IR. With non contrast-enhanced chest CT the dose decreased from 3.4 (range 0.7-7.8) mSv to 0.9 (range 0.1-4.5) mSv. Objective mage quality and diagnostic confidence and acceptability remained the same or improved with IR compared to FBP in most studies while data on diagnostic accuracy was limited.

Conclusion: Radiation dose can be reduced to less than 2 mSv for contrast-enhanced chest CT and non contrast-enhanced chest CT is possible at a submillisievert dose using IR algorithms.
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http://dx.doi.org/10.1016/j.ejrad.2015.07.011DOI Listing
November 2015

Current state in tracking and robotic navigation systems for application in endovascular aortic aneurysm repair.

J Vasc Surg 2015 Jan 14;61(1):256-64. Epub 2014 Oct 14.

Department of Vascular Surgery, University Medical Center, Utrecht, The Netherlands.

Objective: This study reviewed the current developments in manual tracking and robotic navigation technologies for application in endovascular aortic aneurysm repair (EVAR).

Methods: EMBASE and MEDLINE databases were searched for studies reporting manual tracking or robotic navigation systems that are able to manipulate endovascular surgical tools during abdominal or thoracic aortic aneurysm repair. Reports were grouped by the navigation systems and categorized into phantom, animal, and clinical studies. First, the general characteristics of each system were compared. Second, target registration error and deployment error were used to compare the accuracy of the tracking systems. Third, all systems were reviewed for fluoroscopy time (FT), radiation dose, and contrast volumes, if reported, in rigid and nonrigid studies. Fourth, vascular cannulation performance of the systems was compared, studying cannulation time, Imperial College Complex Cannulation Scoring Tool score, and the number of wall hits and catheter movements within rigid studies.

Results: Of 721 articles and references found, 18 studies of four different navigation systems were included: the Aurora (Northern Digital, Waterloo, Ontario, Canada) tracking system, the StealthStation (Medtronic Inc, Minneapolis, Minn) tracking system, an ultrasound localization tracking system, and the Sensei (Hansen Medical, Mountain View, Calif) steerable remote-controlled robotic navigation system. The mean tracking accuracy averaged 1 mm for the three manual tracking systems measured in a rigid environment. An increase of target registration error reaching >3 mm was reported when measured in a nonrigid experimental environment or due to external distortion factors. Except within small-animal studies or case studies, no evidence was found on reduction of clinical outcome parameters, such as FT, radiation dose, and contrast volumes, within clinical EVAR. A comparison of vascular cannulation performance in rigid studies revealed that the Sensei robotic system might have an advantage during advanced cannulation compared with standard cannulation within complex cannulations tasks.

Conclusions: This review summarizes the current studies on manual tracking and robotic navigation systems for application in EVAR. The main focus of these systems is improving aortic vessel cannulation, required in complex EVAR, in which the robotic system with the improved steerability is favored over manual tracking systems or conventional cannulation. All reviewed tracking systems still require X-ray for anatomic imaging, stent graft deployment, and device registration. Although the current reviewed endovascular navigation systems have shown their potential in phantom and animal studies, clinical trials are too limited to conclude that these systems can improve EVAR outcomes or that they can systematically reduce FTs, radiation doses, and contrast volumes during (complex) EVAR.
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http://dx.doi.org/10.1016/j.jvs.2014.08.069DOI Listing
January 2015