Comparison of Radiation Exposure during Endovascular Treatment of Peripheral Arterial Disease with Flat-Panel Detectors on Mobile C-arm versus Fixed Systems

Fixed compared to mobile imaging arms for transcarotid artery revascularization

OBJECTIVE

Transcarotid artery revascularization (TCAR) is a new surgical option for carotid artery stenosis. While this procedure is optimally performed in hybrid operating rooms (OR), it is currently unclear whether it could be safely performed using portable, C-arm fluoroscopy with equivalent results. The aim of this study is to determine whether there are differences in intraoperative and perioperative outcomes stratified by imaging modality.

METHODS

A retrospective review of all TCAR procedures attempted within our health system was performed, capturing all cases between September 2017 and May 2022. Procedures were divided into 2 cohorts, based on whether they were performed in a hybrid OR or with portable, C-arm in a standard OR. Patient demographics, intraoperative results, and postoperative outcomes were compared using univariate strategies.

RESULTS

A total of 503 patients were included for review, of which 422 were performed in a hybrid OR (84%) and 81 were performed using a portable C-arm (16%). Intraoperatively, an increased estimated blood loss (47.7 ± 54.7 vs 26.1 ± 26.9 mLs, p < 0.01) and operative time was found in the cases performed in a hybrid OR. However, the fluoroscopy time was lower (4.0 ± 2.6 vs 5.2 ± 5.8 min, p = 0.01) in the setting of advanced intraoperative imaging. Postoperatively, we found no differences with respect to myocardial infarction (0.2% vs. 0%, p > 0.99), stroke (2.4% vs. 2.5%, p = 0.96), or death (0.7% vs. 2.5%, p = 0.15) between groups.

CONCLUSIONS

While there are some intraoperative variabilities between TCAR performed in hybrid versus standard ORs, postoperative outcomes are comparable. Therefore, the lack of a hybrid room should not be a deterrent to the adoption of TCAR.

Superficial Femoral Artery Recanalization Using Fiber Optic RealShape Technology

Purpose: Report of a successful case of endovascular recanalization of an occluded superficial femoral artery (SFA) using Fiber Optic RealShape (FORS) technology. Case Report: A 79-year-old male was referred for evaluation of multiple ischemic pretibial ulcers of the right lower extremity. Computed tomography–angiography (CTA) imaging confirmed significant stenosis of the right common femoral artery (CFA) and an occlusion of the SFA from its origin to the Hunter’s canal. The patient was treated with a hybrid surgical procedure: an endarterectomy of the CFA and SFA origin was performed combined with an endovascular recanalization of the occluded SFA using FORS technology. During recanalization, the FORS guidewire slowly twisted subintimally around the occluded lumen of the SFA, maintaining the created corkscrew shape after pre-dilation with the percutaneous transluminal angioplasty (PTA) balloon and subsequent stenting. Conclusions: FORS technology can be successfully used during recanalization of an occluded SFA without the use of fluoroscopy. The corkscrew shape formed during recanalization in this case was retained during PTA balloon pre-dilation and stenting; this potentially improves hemodynamics and thereby reduces the risk of in-stent restenosis. However, expanding patient series and longer follow-up data are needed to increase the understanding of the feasibility and effectiveness of using FORS in the treatment of peripheral arterial occlusive disease.

Radiation distribution in a hybrid operating room, utilizing different X-ray imaging systems: investigations to minimize occupational exposure

Objectives

To reduce occupational radiation exposure in a hybrid operating room (OR) used for three-dimensional (3D) image guided spine procedures. The effects of staff positioning, different X-ray imaging systems, and freestanding radiation protection shields (RPSs) were considered.

Methods

An anthropomorphic phantom was imaged with a robotic ceiling mounted hybrid OR C-arm cone beam CT (hCBCT), a mobile O-arm CBCT (oCBCT), and a mobile two-dimensional C-arm fluoroscopy system. The resulting scatter doses were measured at different positions in the hybrid OR using active personal dosimeters and an ionization chamber. Two types of RPSs were evaluated.

Results

Using the hCBCT system instead of the oCBCT system reduced the occupational radiation dose on average by 22%. At 200 cm from the phantom, scatter doses from the hCBCT were 27% lower compared with the oCBCT. One rotational acquisition with hCBCT or oCBCT corresponded to 12 or 16 min of fluoroscopy with the C-arm, respectively. The scatter dose decreased by more than 90% behind an RPS. However, the protection was slightly less effective at 60 cm behind the RPS, due to tertiary scatter from the surroundings.

Conclusions

For 3D image guided spine procedures in the hybrid OR, occupational radiation exposure is lowered by using hCBCT rather than oCBCT. Radiation exposure can also be decreased by optimal staff positioning in the OR, considering distance to the source and positioning relative to the walls, ceiling, and RPS. In this setting and workflow, staff can use RPSs instead of heavy aprons during intraoperative CBCT imaging, to achieve effective whole body dose reduction with improved comfort.

EndoNaut two-dimensional fusion imaging with a mobile C-arm for endovascular treatment of occlusive peripheral arterial disease

BACKGROUND

Endovascular treatment has become the first-line strategy for peripheral arterial disease (PAD). Given the number of procedures required, any technology associated with a reduction in radiation exposure and contrast volume is highly relevant. In the present study, we evaluated whether two-dimensional (2D) fusion imaging could reduce the radiation exposure and contrast volume during endovascular treatment of occlusive PAD.

METHODS

Our consecutive, retrospective, single-center, nonrandomized comparative trial included patients with PAD at the femoral, popliteal, and/or tibial level, at any clinical stage, if they were candidates for endovascular revascularization. Patients were treated with or without the EndoNaut 2D fusion imaging system (Therenva, Rennes, France) in a nonhybrid room with the same Cios Alpha mobile C-arm (Siemens, Munich, Germany). The indirect dose-area product and contrast medium volume were recorded.

RESULTS

Between March 2018 and April 2020, 255 patients underwent endovascular femoropopliteal revascularization with (n = 124) or without (n = 131) 2D fusion imaging. The volume of injected contrast medium (34.7 ± 13.8 mL vs 51.3 ± 26.7 mL; P < .001) and dose-area product (8.9 ± 9.9 Gy/cm² vs 13.5 ± 14.0 Gy/cm²; P = .003) were significantly lower for the 2D fusion imaging group than for the control group. A subgroup analysis of complex (TransAtlantic Inter-Society Consensus for the Management of Peripheral Arterial Disease C/D) lesions showed similar results. Stratification of the fusion imaging group into three subgroups, according to the procedure dates, showed no effect of a potential learning curve on the operative parameters.

CONCLUSIONS

The results from the present study showed a significant reduction in the contrast volume and radiation dose for endovascular treatment of PAD when applying 2D fusion imaging technology. Overall, a reduction of >30% was observed for both operative parameters, without excessive training requirements, highlighting the potential benefits of using 2D fusion imaging when performing endovascular revascularization for PAD.

Fusion imaging guidance for endovascular recanalization of peripheral occlusive disease

OBJECTIVE

Endovascular procedures are now the first line option for treatment of lower extremity arterial disease. Fusion imaging guidance has been reported to reduce radiation exposure and reintervention rates during fenestrated and branched endovascular repairs, but limited literature exists on its benefits during lower extremity arterial disease endovascular procedures, and more specifically peripheral occlusive disease (POD). This study aims to evaluate the radiation exposure and technical success benefits of fusion imaging guidance in a large cohort of patients treated endovascularly for complex POD.

METHODS

From January 2017 to September 2019, in a single center, all consecutive patients presenting symptomatic occlusions (Rutherford Baker categories 3 to 6) in the setting of POD and treated endovascularly were retrospectively assessed for inclusion. All procedures were performed under augmented fluoroscopy guidance (Vessel ASSIST, GE Healthcare), overlaying on live imaging the 3D path for transluminal recanalization based on the preoperative computed tomography angiography. Technical success, dose area product (DAP), total cumulated air kerma (CAK), and fluoroscopy time were collected. DAP results were compared with the literature.

RESULTS

During the study period, 179 patients were treated for iliac (n = 56) or femoropopliteal (n = 123) symptomatic arterial occlusions. Technical success was reported in 171 of 179 procedures (95.5%). The use of a re-entry catheter was required to achieve technical success in 11 patients (6.1%). Mean DAP and CAK were 15.44 Gy·cm² and 135 mGy, respectively, with a mean fluoroscopy time of 15.04 minutes. DAP and CAK were significantly higher in the iliac group when compared with the femoropopliteal group, although fluoroscopy time was not significantly different. DAP was lower than levels reported in the literature.

CONCLUSIONS

Routine use of fusion imaging guidance during POD endovascular treatment is associated with low radiation exposure, high technical success, and reduced need for re-entry systems.

Diagnostic reference levels during fluoroscopically guided interventions using mobile C-arms in operating rooms: A national multicentric survey

PURPOSE

To establish diagnostic reference levels (DRLs) and achievable levels (ALs) for the most common fluoroscopically guided interventions (FGIs) performed in operating rooms using mobile C-arm equipment.

METHODS

A national survey was performed in 57 centers in France. Anonymous data from 6817 patients undergoing FGIs were prospectively collected over a period of 7 months. DRLs (third quartile of the distribution) and ALs (median of the distribution) were determined for each type of intervention in terms of kerma area product (KAP) and fluoroscopy time (FT).

RESULTS

DRLs and ALs were proposed for 31 procedure types related to seven surgical specialties: orthopedics (n = 9), urology (n = 3), vascular (n = 6), cardiology (n = 5), neurosurgery (n = 3), gastrointestinal (n = 3), and multi-specialty (n = 2). DRLs in terms of KAP ranged from 0.1 Gy·cm² for hallux valgus to 78 Gy·cm² for abdominal aortic aneurysm endovascular repair. A factor of 155 was obtained between the FTs for a herniated lumbar disk (0.2 min) and an abdominal aortic aneurysm endovascular repair (31 min). The highest variations were obtained within orthopedic procedures in terms of KAP (ratio 122) and within gastrointestinal procedures in terms of FT (ratio 9). Overall, the FGIs associated with the highest radiation exposure (KAP > 10 Gy·cm²) were found in the cardiology, vascular, and gastrointestinal specialties.

CONCLUSIONS

DRLs and ALs are suggested for a wide range of FGIs performed in operating rooms using a mobile C-arm. We aim at providing a practical optimization tool for medical physicists and surgeons.

Fusion Imaging with a Mobile C-Arm for Peripheral Arterial Disease

BACKGROUND

Fusion imaging makes it possible to improve endovascular procedures and is mainly used in hybrid rooms for aortic procedures. The objective of this study was to evaluate the feasibility of fusion imaging for femoropopliteal endovascular procedures with a mobile flat plane sensor and dedicated software to assist endovascular navigation.

MATERIALS AND METHODS

Between May and December 2017, 41 patients requiring femoropopliteal endovascular revascularization were included. Interventions were carried out in a conventional surgical room equipped with a mobile plane sensor (Cios Alpha, Siemens). The numerical video stream was transmitted to an angionavigation station (EndoNaut (EN), Therenva). The software created an osseous and arterial panorama of the treated limb from the angiographies carried out at the beginning of procedure. After each displacement of the table, the software relocated the current image on the osseous panorama, with 2D-2D resetting, and amalgamated the mask of the arterial panorama. The success rates of creation of osseous and arterial panorama and the success of relocation were evaluated. The data concerning irradiation, the volume of contrast (VC) injected, and operative times were recorded.

RESULTS

Osseous panoramas could be automatically generated for the 41 procedures, without manual adjustment in 33 cases (80.5%). About 35 relocations based on a 2D-2D resetting could be obtained in the 41 procedures, with a success rate of 85%. The causes of failure were a change in table height or arch angulation. The average duration of intervention was 74.5 min. The irradiation parameters were duration of fluoroscopy 17.8 ± 13.1 min, air kerma 80.5 ± 68.4 mGy, and dose area product 2140 ± 1599 μGy m². The average VC was 24.5 ± 14 mL.

CONCLUSIONS

This preliminary study showed that fusion imaging is possible in a nonhybrid room for peripheral procedures. Imagery of mobile C-arms can be improved for femoropopliteal endovascular procedures without heavy equipment. These imagery tools bring an operative comfort and could probably reduce irradiation and the injected VC. The clinical benefit must be evaluated in more patients in a randomized comparative study with a rigorous methodology.

A Blueprint for Success: Design and Implementation of an Ideal Bronchoscopy Suite

Bronchoscopy is essential to the practice of pulmonary medicine. It is an important diagnostic and therapeutic tool for many disease processes. Bronchoscopy can be performed in a variety of clinical settings, from the bedside to an operating room. Although bronchoscopy has been practiced for more than a century, consensus recommendations from stakeholders have yet to be developed for the planning, implementation, and construction of a bronchoscopy suite. A wide range of procedures can be performed via bronchoscopy; therefore, the required tools and the procedure area must be aligned with the needs of the facility. Designing a bronchoscopy suite is by no means a "one size fits all" process. We present an overview of critical features to be considered in the planning for an ideal bronchoscopy suite. We use the term "ideal" because it represents a subjective conception of what is perfect and does not convey a rigid, universal blueprint.

New advances in intra-operative imaging in trauma

The invention of flat-panel detectors led to a revolution in medical imaging. The major benefits of this technology are a higher image quality and dose reduction. Flat-panel detectors have proved to be superior to standard C-arms (= C-arm with radiograph source and image intensifier).

Cone-beam computed tomography (cone-beam CT) is a 3D data set, which can be acquired with a flat-panel detector. The cone-shaped beam is used for 3D data generation. For cone-beam CT acquisition, the flat-panel detector rotates around the patient lying on the operating table. Intra-operative cone-beam CT can be a very helpful tool in orthopaedic surgery. Immediate control of fracture reduction and implant positioning in high image quality can reduce the need for secondary revision surgery due to implant malposition.

In recent years there has been a revival of standard fan beam CT technology in operating rooms. Fixed and mobile systems are available. Fixed systems are typically placed on a sliding gantry. Different mobile intra-operative CT scanners were recently introduced. Due to their mobility, they are not bound to a specific operating room. The use of standard intra-operative CT scanners results in high 3D image quality but, in comparison with a cone-beam CT scanner, fluoroscopy is not possible.

The introduction of flat-panel detectors has led to improvements in intra-operative image quality combined with dose reduction. The possibility of high-quality 3D imaging in combination with navigation can assure optimal implant placement. Due to immediate control of the osteosynthesis, revision surgery at a later time can be prevented.

Cite this article: EFORT Open Rev 2018;3 DOI: 10.1302/2058-5241.3.170055

Analysis of Radiation Effects in Digital Subtraction Angiography of Intracranial Artery Stenosis

BACKGROUND

Intracranial artery stenosis (IAS) is the most common cause for acute cerebral accidents. Digital subtraction angiography (DSA) is the gold standard to detect IAS and usually brings excess radiation exposure to examinees and examiners. The artery pathology might influence the interventional procedure, causing prolonged radiation effects. However, no studies on the association between IAS pathology and operational parameters are available.

METHODS

A retrospective analysis was conducted on 93 patients with first-ever stroke/transient ischemic attack, who received DSA examination within 3 months from onset in this single center. Comparison of baseline characteristics was determined by 2-tailed Student's t-test or the chi-square test between subjects with and without IAS. A binary logistic regression analysis was performed to determine the association between IAS pathology and the items with a P value <0.05 in Student's t-test or chi-square test.

RESULTS

There were 93 candidates (42 with IAS and 51 without IAS) in this study. The 2 groups shared no significance of the baseline characteristics (P > 0.05). We found a significantly higher total time, higher kerma area product, greater total dose, and greater DSA dose in the IAS group than in those without IAS (P < 0.05). A binary logistic regression analysis indicated the significant association between total time and IAS pathology (P < 0.05) but no significance in kerma area product, radiation dose, and DSA dose (P > 0.05).

CONCLUSIONS

IAS pathology would indicate a prolonged total time of DSA procedure in clinical practice. However, the radiation effects would not change with pathologic changes.

Radioprotection Measures during the Learning Curve with Hybrid Operating Rooms

BACKGROUND

Endovascular procedures come with a potential risk of radiation hazards both to patients and to the vascular staff. Classically, most endovascular interventions took place in regular operating rooms (ORs) using a fluoroscopy C-arm unit controlled by a third party. Hybrid operating rooms (HORs) provide an optimal surgical suit with all the qualities of a fixed C-arm device, while allowing the device to be controlled by the surgical team. The latest studies suggest that an operator-controlled system may reduce the radiation dose. The purpose of the present study is to determine the amount of absorbed radiation using an HOR in comparison with a portable C-arm unit and to assess whether the radioprotection awareness of the surgical team influences the radiation exposure. The primary end point was the effective dose in milliSievert (mSv) for the surgical team and the average dose-area product (ADAP) in Gray-meters squared (Gym²) for patients.

METHODS

The values of absorbed radiation of the surgical team's dosimeters were collected from January 2015 to May 2016. The HOR was installed in June 2015, and a radioprotection seminar was given in October 2015. The HOR-issued radiation, measured by the maximum dose-area product, ADAP, average dose (AD) per procedure, maximum dose per procedure per month, maximum fluoroscopy time, average fluoroscopic time, peak skin dose, and average skin dose (ASD), was collected monthly from September 2015 to July 2016. The timeline was divided into 3 periods: 5 months pre-HOR (Pre-HOR), 5 months after the HOR installation (PreS-HOR), and 5 months after a radioprotection seminar (PostS-HOR).

RESULTS

The average number of procedures per month was 22.55 (±4.9), including endovascular aneurysm repair/thoracic endovascular aneurysm repair, carotid, visceral, and upper and lower limb endovascular revascularization. The average amount of absorbed radiation by the surgeons during PreS-HOR was 1.07 ± 0.4 mSv, which was higher than the other periods (Pre-HOR 0.06 ± 0.03 mSv, P = 0.002; PostS-HOR 0.14 ± 0.09 mSv, P = 0.000, respectively). The ADAP during PreS-HOR was 0.016 ± 0.01 Gym², which was lower than the PostS-HOR (0.001 ± 0.002 Gym²) (P = 0.034). The AD during PreS-HOR was 0.78 ± 0.3 Gy and 0.39 ± 0.3 Gy during PostS-HOR (P = 0.098). The ASD during PreS-HOR was 0.40 ± 0.2 Gy and 0.20 ± 0.1 Gy during PostS-HOR (P = 0.099).

CONCLUSIONS

In our experience, the HOR increases the amount of absorbed radiation for both patients and surgeons. The radioprotection seminars are of utmost importance to provide a continued training and optimize the use of ionizing radiation while using an HOR. Despite the awareness of the surgical team in the radioprotection field, the amount of absorbed radiation using an HOR is higher than the one using a C-Arm unit.