Quantification of true lumen helical morphology and chirality in type B aortic dissections.

Chirality is a fundamental property in many biological systems. Motivated by previous observations of helical aortic blood flow, aortic tissue fibers, and propagation of aortic dissections, we introduce methods to characterize helical morphology of aortic dissections. After validation on computer-generated phantoms, the methods were applied to patients with type B dissection. For this cohort, there was a distinct bimodal distribution of helical propagation of the dissection with either achiral or exclusively right-handed chirality, with no intermediate cases or left-handed cases. This clear grouping indicates that dissection propagation favors these two modes, which is potentially due to the right-handedness of helical aortic blood flow and cell orientation. The characterization of dissection chirality and quantification of helical morphology advances our understanding of dissection pathology and lays a foundation for applications in clinical research and treatment practice. For example, the chirality and magnitude of helical metrics of dissections may indicate risk of dissection progression, help define treatment and surveillance strategies, and enable development of novel devices that account for various helical morphologies.NEW & NOTEWORTHY A novel definition of helical propagation of type B aortic dissections reveals a distinct bimodality, with the true lumen being either achiral (nonhelical) or exclusively right-handed. This right-handed chirality is consistent with anatomic and physiological phenomena such as right-handed twist during left ventricle contraction, helical blood flow, and tissue fiber direction. The helical character of aortic dissections may be useful for pathology research, diagnostics, treatment selection, therapeutic durability prediction, and aortic device design.

Modern Image Acquisition System Reduces Radiation Exposure to Patients and Staff During Complex Endovascular Aortic Repair.

OBJECTIVE: Radiation damage during complex endovascular aortic repair (EVAR) is of major concern to patients and medical staff. This study investigates primarily the influence of different acquisition systems (Allura ClarityIQ vs. Allura Xper, Philips Healthcare, Best, the Netherlands) on radiation dose. Secondly, radiation exposure was analysed for operator positions as well as for procedure and patient specific parameters. METHODS: This was a retrospective study of prospectively collected data. The study prospectively included 62 consecutive patients (mean age 71.2 ± 8.4 years; 63% males) who underwent complex EVAR including fenestrated or branched EVAR of the thoraco-abdominal or the aortic arch from 30 June 2015 to 20 May 2016. In half the patients an advanced dose and real time image noise reduction technology (Allura ClarityIQ) was used, and in the other half the reference acquisition system (Allura Xper) was used. Patient demographics included age, gender, and body mass index. RESULTS: Sixty-two patients with mean age of 71.2 ± 8.4 years (63% males; 39/62) were treated using either Allura ClarityIQ or Allura Xper. Patients treated using Allura ClarityIQ had lower cumulative dose area product (18,948.3 ± 14,648.5 cGy cm2vs. 38,512.4 ± 24,105.4 cGy cm2, p < 0.001) and air kerma (2237.9 ± 1808 mGy vs. 4031 ± 3260.2 mGy, p = .010) in comparison with patients treated using Allura Xper. CONCLUSION: Advanced dose and real time image noise reduction technology, such as Allura ClarityIQ, is a useful tool to lower the amount of radiation for patient and staff during complex endovascular aortic procedures.

Use of carbon dioxide for therapeutic decision-making in endoleaks: a case report / Uso de CO2 na tomada de decisão terapêutica de endoleak: relato de caso

Abstract Endovascular aneurysm repair is currently the most frequently treatment modality for infrarenal aortic aneurysms. Endoleaks are the most common cause of reintervention after endovascular aneurysm repair. It is often unclear which type of endoleak is the correct diagnose, making the treatment decision difficult. We report the case of a 72-year-old man with an endoleak two years after endovascular aneurysm repair. Images suggested a type III endoleak, but this was not confirmed by contrast aortography. We proceeded with the investigation using aortography with carbon dioxide and observed a type IA endoleak. This was successfully treated by implantation of a proximal cuff. A review of the literature shows that the role of carbon dioxide in endoleak management is still unclear. We present a case in which carbon dioxide was essential to both diagnosis and therapeutic decision-making in a type IA endoleak.

Resumo O tratamento endovascular dos aneurismas de aorta abdominal é atualmente a modalidade de tratamento mais comum. Os endoleaks representam a causa mais frequente de reintervenção após o tratamento endovascular. O diagnóstico do tipo de endoleak frequentemente é incerto, tornando o tratamento desafiador. Apresentamos o caso de um paciente de 72 anos, com endoleak após 2 anos de tratamento endovascular de aneurisma de aorta abdominal. Os exames de imagem pré-operatórios sugeriam um endoleak tipo III; entretanto, durante aortografia com contraste iodado, não foi possível identificá-lo. Optamos por realizar aortografia com dióxido de carbono (CO2), sendo, então, identificado um endoleak tipo IA, que foi tratado com sucesso com o uso de uma extensão (cuff) proximal. O papel do CO2 no diagnóstico de endoleaks ainda não está claro. Relatamos um caso em que o uso do CO2 foi essencial para o diagnóstico e para a decisão de tratamento do endoleak tipo IA.

Fusion Imaging for EVAR with Mobile C-arm.

BACKGROUND: Fusion imaging is a technique that facilitates endovascular navigation but is only available in hybrid rooms. The goal of this study was to evaluate the feasibility of fusion imaging with a mobile C-arm in a conventional operating room through the use of an angionavigation station. METHODS: From May 2016 to June 2017, the study included all patients who underwent an aortic stent graft procedure in a conventional operating room with a mobile flat-panel detector (Cios Alpha, Siemens) connected to an angionavigation station (EndoNaut, Therenva). The intention was to perform preoperative 3D computerized tomography/perioperative 2D fluoroscopy fusion imaging using an automatic registration process. Registration was considered successful when the software was able to correctly overlay preoperative 3D vascular structures onto the fluoroscopy image. For EVAR, contrast dose, operation time, and fluoroscopy time (FT) were compared with those of a control group drawn from the department's database who underwent a procedure with a C-arm image intensifier. RESULTS: The study included 54 patients, and the procedures performed were 49 EVAR, 2 TEVAR, 2 IBD, and 1 FEVAR. Of the 178 registrations that were initialized, it was possible to use the fusion imaging in 170 cases, that is, a 95.5% success rate. In the EVAR comparison, there were no difference with the control group (n = 103) for FT (21.9 ± 12 vs. 19.5 ± 13 min; P = 0.27), but less contrast agent was used in the group undergoing a procedure with the angionavigation station (42.3 ± 22 mL vs. 81.2 ± 48 mL; P < 0.001), and operation time was shorter (114 ± 44 vs. 140.8 ± 38 min; P < 0.0001). CONCLUSIONS: Fusion imaging is feasible with a mobile C-arm in a conventional operating room and thus represents an alternative to hybrid rooms. Its clinical benefits should be evaluated in a randomized series, but our study already suggests that EVAR procedures might be facilitated with an angionavigation system.

Optimizing imaging and reducing radiation exposure during complex aortic endovascular procedures.

Improvements in endovascular technologies and development of custom-made fenestrated and branched endografts currently allow clinicians to treat complex aortic lesions such as thoraco-abdominal and aortic arch aneurysms once treatable with open repair only. These advances are leading to an increase in the complexity of endovascular procedures which can cause long operation times and high levels of radiation exposure. This in turn places pressure on the vascular surgery community to display more superior interventional skills and radiological practices. Advanced imaging technology in this context represents a strong pillar in the treatment toolbox for delivering the best care at the lowest risk level. Delivering the best patient care while managing the radiation and iodine contrast media risks, especially in frail and renal impaired populations, is the challenge aortic surgeons are facing. Modern hybrid rooms are equipped with a wide range of new imaging applications such as fusion imaging and cone-beam computed tomography (CBCT). If these technologies contribute to reducing radiation, they can be complex and intimidating to master. The aim of this review is to discuss the fundamentals of good radiological practices and to describe the various imaging tools available to the aortic surgeon, both those available today and those we anticipate will be available in the near future, from equipment to software, to perform safe and efficient complex endovascular procedures.

Radiation doses for endovascular aortic repairs performed on mobile and fixed C-arm fluoroscopes and procedure phase-specific radiation distribution.

OBJECTIVE: The objective of this study was to analyze radiation risk to patients during endovascular aneurysm repair (EVAR) using mobile C-arm (MA) or fixed C-arm (FA) fluoroscopes and to describe the dose distribution during the different phases of the procedure. METHODS: Patients treated with EVAR using a single stent graft system between November 2009 and June 2016 were included in this study. The patients were divided into one of two groups (MA or FA) according to the type of C-arm used in the procedure. Data regarding patients' demographics and the total amount of contrast agent (CA) used, dose-area product, and fluoroscopy time for the procedures were prospectively recorded. Based on the dose report from the FA system, five standard and two optional phases of the procedure were identified to determine the dose distribution. RESULTS: Overall, 160 patients were included (mean age, 73.30 ± 8.97 years; 146 men); of these, 107 were treated with an MA system and 53 were treated with an FA system. The mean amounts of CA used were 108.55 ± 42.28 mL in the MA group and 85.37 ± 38.79 mL in the FA group (P = .0014). The mean total dose-area product values were 49.93 ± 38.06 Gy·cm2 in the MA group and 168.34 ± 146.92 Gy·cm2 in the FA group (P < .0001). There was no significant difference in fluoroscopy time between the groups. Per-phase analysis demonstrated that identification of the proximal landing zone and main body deployment required the most radiation, accounting for 24% of the total radiation dose. Overall, 47.6% of the exposure was due to digital subtraction angiography. CONCLUSIONS: Use of an FA system can significantly reduce the amount of CA needed but may also lead to higher radiation doses in EVAR procedures. Dose monitoring remains crucial for the safety of both patients and operators. A detailed analysis of dose distribution is possible with modern systems, which may improve the quality of monitoring in the future.

Experiencia en nuestro centro con Nellix: EndoVascular Aneurysm Sealing (EVAS) system. Un cambio de paradigma en el tratamiento endovascular del aneurisma aórtico / Experience with Nellix: EndoVascular Aneurysm Sealing (EVAS) system. A paradigm shift in endovascular aortic aneurysm treatment

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A phantom study for the comparison of different brands of computed tomography scanners and software packages for endovascular aneurysm repair sizing and planning.

Objectives Correct sizing of endoprostheses used for the treatment of abdominal aortic aneurysms is important to prevent endoleaks and migration. Sizing requires several steps and each step introduces a possible sizing error. The goal of this study was to investigate the magnitude of these errors compared to the golden standard: a vessel phantom. This study focuses on the errors in sizing with three different brands of computed tomography angiography scanners in combination with three reconstruction software packages. Methods Three phantoms with a different diameter, altitude and azimuth were scanned with three computed tomography scanners: Toshiba Aquilion 64-slice, Philips Brilliance iCT 256-slice and Siemens Somatom Sensation 64-slice. The phantom diameters were determined in the stretched view after central lumen line reconstruction by three observers using Simbionix PROcedure Rehearsal Studio, 3mensio and TeraRecon planning software. The observers, all novices in sizing endoprostheses using planning software, measured 108 slices each. Two senior vascular surgeons set the tolerated error margin of sizing on ±1.0 mm. Results In total, 11.3% of the measurements (73/648) were outside the set margins of ±1.0 mm from the phantom diameter, with significant differences between the scanner types (14.8%, 12.1%, 6.9% for the Siemens scanner, Philips scanner and Toshiba scanner, respectively, p-value = 0.032), but not between the software packages (8.3%, 11.1%, 14.4%, p-value = 0.141) or the observers (10.6%, 9.7%, 13.4%, p-value = 0.448). Conclusions It can be concluded that the errors in sizing were independent of the used software packages, but the phantoms scanned with Siemens scanner were significantly more measured incorrectly than the phantoms scanned with the Toshiba scanner. Consequently, awareness on the type of computed tomography scanner and computed tomography scanner setting is necessary, especially in complex abdominal aortic aneurysms sizing for fenestrated or branched endovascular aneurysm repair if appropriate the sizing is of upmost importance.

Use of Synchrotron Radiation to Accurately Assess Cross-Sectional Area Reduction of the Aortic Branch Ostia Caused by Suprarenal Stent Wires.

PURPOSE: To compare in vivo the use of synchrotron radiation to computed tomography angiography (CTA) for the measurement of cross-sectional area (CSA) reduction of the aortic branch ostia caused by suprarenal stent-graft wires. METHODS: This study was performed with a Zenith stent-graft placed in a phantom of the human aorta to simulate treatment of abdominal aortic aneurysm. Synchrotron radiation scans were performed using beam energies between 40 and 100 keV and spatial resolution of 19.88 µm per pixel. CSA reduction of the aortic branch ostia by suprarenal stent wires was calculated based on these exposure factors and compared with measurements from CTA images acquired on a 64-row scanner with slice thicknesses of 1.0, 1.5, and 2.0 mm. RESULTS: Images acquired with synchrotron radiation showed <10% of the CSA occupied by stent wires when a single wire crossed a renal artery ostium and <20% for 2 wires crossing a renovisceral branch ostium. The corresponding areas ranged from 24% to 25% for a single wire and from 40% to 48% for double wires crossing the branch ostia when measured on CT images. The stent wire was accurately assessed on synchrotron radiation with a diameter between 0.38±0.01 and 0.53±0.03 mm, which is close to the actual size of 0.47±0.01 mm. The wire diameter measured on CT images was greatly overestimated (1.15±0.01 to 1.57±0.02 mm). CONCLUSION: CTA has inferior spatial resolution that hinders accurate assessment of CSA reduction. This experiment demonstrated the superiority of synchrotron radiation over CTA for more accurate assessment of aortic stent wires and CSA reduction of the aortic branch ostia.

How Precise Are Preinterventional Measurements Using Centerline Analysis Applications? Objective Ground Truth Evaluation Reveals Software-Specific Centerline Characteristics.

PURPOSE: To evaluate different centerline analysis applications using objective ground truth from realistic aortic aneurysm phantoms with precisely defined geometry and centerlines to overcome the lack of unknown true dimensions in previously published in vivo validation studies. METHODS: Three aortic phantoms were created using computer-aided design (CAD) software and a 3-dimensional (3D) printer. Computed tomography angiograms (CTAs) of phantoms and 3 patients were analyzed with 3 clinically approved and 1 research software application. The 3D centerline coordinates, intraluminal diameters, and lengths were validated against CAD ground truth using a dedicated evaluation software platform. RESULTS: The 3D centerline position mean error ranged from 0.7±0.8 to 2.9±2.5 mm between tested applications. All applications calculated centerlines significantly different from ground truth. Diameter mean errors varied from 0.5±1.2 to 1.1±1.0 mm among 3 applications, but exceeded 8.0±11.0 mm with one application due to an unsteady distortion of luminal dimensions along the centerline. All tested commercially available software tools systematically underestimated centerline total lengths by -4.6±0.9 mm to -10.4±4.3 mm (maximum error -14.6 mm). Applications with the highest 3D centerline accuracy yielded the most precise diameter and length measurements. CONCLUSION: One clinically approved application did not provide reproducible centerline-based analysis results, while another approved application showed length errors that might influence stent-graft choice and procedure success. The variety and specific characteristics of endovascular aneurysm repair planning software tools require scientific evaluation and user awareness.

Endovascular Repair of a Short Neck Abdominal Aortic Aneurysm with a Physician-Modified Vascutek Anaconda Stent Graft.

An 81-year-old woman was referred for the treatment of a 79-mm-diameter short neck abdominal aortic aneurysm with highly tortuous iliac arteries. She was considered at high risk for open repair and not suitable for standard endovascular repair given the short length of the proximal neck. Delay for a manufactured custom-made fenestrated stent graft was too long given the diameter of the aneurysm. A flexible stent graft was preferred because of severe iliac tortuosity. Endovascular repair was performed using a physician-modified Anaconda stent graft with 1 fenestration for the left renal artery. The technique for device modification and implantation is described. Postoperative course was uneventful and 1-year computed tomography scan showed complete exclusion of the aneurysm sac and patent left renal artery.

Influential Factors on the Evaluation of Adamkiewicz Artery Using a 320-Detector Row Computed Tomography Device.

BACKGROUND: Understanding the difference of Adamkiewicz artery (AKA) presentation in healthy and diseased subjects, and the influence of atherosclerotic factors prevalent in aortic disease patients, are important for aortic disease therapeutic planning. This study used a 320-detector row computed tomography (CT) device to examine the impact of clinical aspects of AKA identification in individuals with and without aortic disease. METHODS: Angio-CTs obtained from 115 patients were assessed and the individuals grouped according to the presence or absence of aortic disease. Datasets were analyzed using OsiriX software, and AKA was identified by three-dimensional multiplanar reconstruction. RESULTS: The group without aortic disease (Group A) comprised 32 (52.5%) men and 29 women, with a mean age of 53.7 ± 16.8 years. The group with aortic disease (Group B) comprised 31 (57.4%) men and 23 women, with a mean age of 64.8 ± 11.6 years. AKA was identified in 49 (80.3%) participants of Group A and 23 (42.6%) individuals of Group B (P ≤ 0.0001). In 53 cases (73.6%), AKA originated on the left side. AKA was mainly detected on the left side (73.6%), at the level of T10 to T12 (70%). Tobacco smokers, former smokers, and hypertensive patients had increased odds of having undetected AKA. CONCLUSIONS: Using the method described and a state of the art 320-detector row CT device, AKA was detected more frequently among individuals without aortic disease. Thus, aortic disease and atherosclerotic risk factors hindered AKA detection.

Tratamiento híbrido de aneurisma de arco aórtico y aorta descendente en paciente con arco aórtico a la derecha y arteria subclavia izquierda aberrante / Hybrid treatment of aortic arch and descending aorta aneurysm in a patient with right aortic arch and aberrant left subclavian artery

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The use of intraosseous needles for injection of contrast media for computed tomographic angiography of the thoracic aorta.

BACKGROUND: The objective of this study is to evaluate the safety and quality of computed tomographic angiography of the thoracic aorta (CTA-TA) exams performed using intraosseous needle intravenous access (ION-IVA) for contrast media injection (CMI). METHODS: All CTA-TA exams at the study institution performed between 1/1/2013 and 8/14/2015 were reviewed retrospectively to identify those exams which had been performed using ION-IVA (ION-exams). ION-exams were then analyzed to determine aortic attenuation and contrast-to-noise ratio (CNR). Linear regression was used to determine how injection rate and other variables affected image quality for ION-exams. Patient electronic medical records were reviewed to identify any adverse events related to CTA-TA or ION-IVA. RESULTS: 17 (∼0.2%) of 7401 exams were ION-exams. ION-exam CMI rates varied between 2.5 and 4 ml/s. Mean attenuation was 312 HU (SD 88 HU) and mean CNR was 25 (SD 9.9). A strong positive linear association between attenuation and injection rate was found. No immediate or delayed complications related to the ION-exams, or intraosseous needle use in general, occurred. CONCLUSION: For CTA-TA, ION-IVA appears to be a safe and effective route for CMI at rates up to 4 ml/s.

What should we expect from the hybrid room?

The concept of hybrid room was defined as an optimized surgical theater, offering the best compromise between asepsis criteria from standard surgical rooms and high quality imaging equipment from fixed radiological suites. This review aimed at summarizing what vascular surgeons should expect from hybrid rooms in daily practice and in the near future.

Utilidad de la angiografía rotacional 3D en el diagnóstico de origen anómalo de arteria coronaria izquierda en tronco pulmonar / Use of 3D-rotational angiography in the diagnosis of the anomalous origin of the left coronary artery in the pulmonary artery

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Comparison of Radiation Exposure Associated With Intraoperative Cone-Beam Computed Tomography and Follow-up Multidetector Computed Tomography Angiography for Evaluating Endovascular Aneurysm Repairs.

PURPOSE: To compare the radiation exposure associated with intraoperative contrast-enhanced cone-beam computed tomography (ceCBCT) acquisitions to standard 3-phase multidetector computed tomography (MDCT) angiography used for assessing technical success after endovascular aortic repair (EVAR). METHODS: Effective doses (EDs) were calculated for 66 EVAR patients (mean age 71 years; 61 men) with a mean 27.7-kg/m(2) body mass index (range 17-49) who had both intraoperative ceCBCT and postoperative 3-phase MDCT angiography between November 2012 and April 2015. In addition, EDs were directly determined using thermoluminescent dosimeters (TLDs) embedded in anthropomorphic phantoms with body mass indexes of 22 and 30 kg/m(2) Effective doses were calculated by summing doses recorded by all TLDs corresponding to a specific tissue type before applying the International Commission on Radiological Protection (ICRP) 60 and 103 weighting factors. EDs were compared with each other for both imaging modalities as well as to TLD measurements. RESULTS: Average EDs of the patient collective were 4.9±1.1 mSv for ceCBCT, 2.6±1.2 mSv for single-phase MDCT (46% decrease, covering solely the area of the implanted endograft), and 13.6±5.5 mSv for comprehensive 3-phase MDCT examinations (178% increase, anatomical coverage from the aortic arch to femoral artery bifurcation). EDs determined in phantom measurements ranged from 3.1 to 4.5 mSv for ceCBCT, amounting to 2.6 mSv for a single MDCT phase (15% to 40% decrease) using ICRP 60 conversion factors. Applying ICRP 103 factors resulted in higher values for ceCBCT and slightly lower ones for MDCT. CONCLUSION: ceCBCT offers the chance for immediate intraoperative revisions of endograft-related problems. Requiring only a single-phase acquisition, ceCBCT is associated with a considerable reduction in ED (50%-75%) compared to standard 3-phase MDCT angiography after EVAR. On the other hand, MDCT has a larger field of view and is associated with less radiation exposure for a single phase (reduction of 20%-60%) if only the stented region is covered; however, MDCT angiography also uses larger amounts of contrast.

CT angiography of the aorta using 80 kVp in combination with sinogram-affirmed iterative reconstruction and automated tube current modulation: Effects on image quality and radiation dose.

INTRODUCTION: The objective of this study was to evaluate image quality and radiation dose of a CT angiography (CTA) protocol using 80 kVp in combination with iterative reconstruction and automated tube current modulation. METHODS: Ninety-five aortic CTA examinations were included in this study. A novel 80 kVp aortic CTA-protocol with iterative reconstruction was introduced in our department in March 2012 for patients with a body mass index (BMI) below 32 kg/m(2). The first 72 consecutive examinations were retrospectively assigned to group A (56 patients, 42 men, 14 women, mean age 69.6 ± 10.7 years, BMI range 19.7-31.1 kg/m(2)). For comparison, the last 23 consecutive examinations performed with the old protocol (100 kVp) were assigned to group B (21 patients, 13 men, 8 women, mean age 67.4 ± 11.1 years, BMI range 19.7-31.9 kg/m(2)). Thoracic and abdominal contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR) and aortic attenuation were assessed. Subjective image quality was rated on a 5-point scale (1 = non diagnostic; 5 = excellent). Furthermore, dose length product (DLP) and volumetric computed tomography dose index (CTDIvol) were analysed. RESULTS: All examinations achieved diagnostic image quality. Attenuation of the aorta was significantly higher in group A compared with B (thoracic: 443.5 ± 90.5 Hounsfield units (HU) vs. 296.0 ± 61.0 HU; abdominal: 426.3 ± 94.2 HU vs. 283.6 ± 60.5 HU; P < 0.05, respectively). CNR, SNR and subjective image quality were comparable between both groups (CNR: 12.8 ± 3.7 vs. 13.0 ± 7.4; SNR 14.4 ± 3.9 vs. 14.9 ± 8.2; subjective image quality: 4.3 ± 0.6 vs. 4.5 ± 0.6; P > 0.05, respectively). CTDIvol and DLP were significantly lower in group A (1.9 ± 0.5 mGy; 139.2 ± 41.1 mGy × cm) as compared with group B (4.2 ± 1.4 mGy; 292.1 ± 91.5 mGy × cm; P < 0.001, respectively). CONCLUSION: Low-dose CTA of the aorta using 80 kVp with iterative reconstruction enables a significant dose reduction of up to 50% compared with a 100 kVp protocol in patients with a BMI below 32 kg/m(2) while diagnostic image quality is maintained.

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

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.

Comparative occupational radiation exposure between fixed and mobile imaging systems.

OBJECTIVE: Endovascular intervention exposes surgical staff to scattered radiation, which varies according to procedure and imaging equipment. The purpose of this study was to determine differences in occupational exposure between procedures performed with fixed imaging (FI) in an endovascular suite compared with conventional mobile imaging (MI) in a standard operating room. METHODS: A series of 116 endovascular cases were performed over a 4-month interval in a dedicated endovascular suite with FI and conventional operating room with MI. All cases were performed at a single institution and radiation dose was recorded using real-time dosimetry badges from Unfors RaySafe (Hopkinton, Mass). A dosimeter was mounted in each room to establish a radiation baseline. Staff dose was recorded using individual badges worn on the torso lead. Total mean air kerma (Kar; mGy, patient dose) and mean case dose (mSv, scattered radiation) were compared between rooms and across all staff positions for cases of varying complexity. Statistical analyses for all continuous variables were performed using t test and analysis of variance where appropriate. RESULTS: A total of 43 cases with MI and 73 cases with FI were performed by four vascular surgeons. Total mean Kar, and case dose were significantly higher with FI compared with MI. (mean ± standard error of the mean, 523 ± 49 mGy vs 98 ± 19 mGy; P < .00001; 0.77 ± 0.03 mSv vs 0.16 ± 0.08 mSv, P < .00001). Exposure for the primary surgeon and assistant was significantly higher with FI compared with MI. Mean exposure for all cases using either imaging modality, was significantly higher for the primary surgeon and assistant than for support staff (ie, nurse, radiology technologist) beyond 6 feet from the X-ray source, indicated according to one-way analysis of variance (MI: P < .00001; FI: P < .00001). Support staff exposure was negligible and did not differ between FI and MI. Room dose stratified according to case complexity (Kar) showed statistically significantly higher scattered radiation in FI vs MI across all quartiles. CONCLUSIONS: The scattered radiation is several-fold higher with FI than MI across all levels of case complexity. Radiation exposure decreases with distance from the radiation source, and is negligible outside of a 6-foot radius. Modern endovascular suites allow high-fidelity imaging, yet additional strategies to minimize exposure and occupational risk are needed.