Ziehm Vision Research Articles

Not All Flat-Panel C-Arms Are Created Equal: A Comparison of Three Major Manufacturers.

Introduction: Flat-panel detector C-arms (FCs) are reported to reduce radiation exposure and improve image quality compared with conventional image intensifier C-arms (CCs). The purpose of this study was to compare radiation exposure and image quality between three commonly used FCs. Materials and Methods: A cadaver model was placed in the prone position to simulate percutaneous nephrolithotomy. We compared the following three FCs: OEC Elite CFD from GE HealthCare, Zenition 70 from Philips, and Ziehm Vision RFD from Ziehm Imaging. To measure the radiation dose, optically stimulated luminescence dosimeters (OSLDs) were utilized during five 300-second trials, conducted under three settings: automatic exposure control (AEC), AEC with low dose (LD), and LD with the lowest pulse rate (LDLP). Ten blinded urologists evaluated the image quality. Data were statistically analyzed using the analysis of variance (ANOVA) and Tukey's B post hoc tests. Results: In the AEC setting, the Philips C-arm demonstrated lower ventral OSLD exposure (42,446 mrad) compared with both the GE (51,076 mrad) and Ziehm (83,178 mrad; p < 0.001) C-arms. Similarly, in the LD setting, the Philips C-arm resulted in less ventral OSLD exposure (25,926 mrad) than both the Ziehm (30,956 mrad) and GE (38,209 mrad; p < 0.001) C-arms. Meanwhile, in the LDLP setting, the Ziehm C-arm showed less ventral OSLD exposure (4019 mrad) than both the GE (7418 mrad) and Philips (8229 mrad; p < 0.001) C-arms. All three manufacturers received adequate image quality ratings at the AEC and LD settings. However, at LDLP, the Ziehm C-arm received inadequate ratings in 8% of images, whereas both the GE and Philips C-arms received 100% adequate ratings (p = 0.016). Conclusions: Radiation produced by flat-panel C-arms varies dramatically, with the highest exposure (Ziehm) being almost double the lowest (Philips) in AEC. Improved picture quality at the lowest settings may come at the cost of increased radiation dose. Surgeons should carefully select the machine and settings to minimize radiation exposure while still preserving the image quality.

Эндоваскулярная имплантация стент-графта в аорту в условиях гибридной операционной при помощи современной мобильной рентгеновской С-дуги: клинический случай

Thanks to the development of modern mobile imaging devices, the treatment of such a serious pa-thology as aortic aneurysm has become more accessible. Thoracic aortic aneurysms are the most common pathology of the thoracic aorta. It occurs with increasing frequency (10 cases per 100,000 people per year). The most common cause of the disease is atherosclerosis. To date, the treat-ment of this serious pathology has become more accessible due to the development of modern mobile imaging devices. As compared to stationary devices, the portable devices for angiography of the latest generation are movable and can be moved from site to site quickly and easily they produce high quality angiograms, the system can be accessible to any health-care institutions. The paper presents the first in Russia successful case of endoprosthetics of the thoracic aorta using mobile C-arm RFD Ziehm Vision. A 75-year-old man was found to have a symptomatic thoracic aortic aneurysm up to 67 mm in diameter, complicated by intramural (1.2 cm thick) and periaortic hematomas and compression atelectasis of the lower lobe of the left lung. The patient underwent prosthetics of the root, ascending part and arch of the aorta with a 30x8 (mm) synthetic prosthesis and intraoperative stenting of the descending thoracic aorta on a mobile C-arm. Our clinical expe-rience shows that difficult hybrid interventions can be successful if they are carried out in a surgical operating room with the use of a high-power C-arm with angiography function. This approach al-lows specialists to obtain image of required quality, with low exposure of a patient to ionizing radia-tion. The method can be used in the absence of stationary angiographs.

Neuronavigation Assistance. Decreased radiation exposure during spinal surgery in patients with severe combined trauma

Absnract. The results of the study of intraoperative x-ray irradiation of the affected two arrays are presented: the main array using neuronavigation and the control group, where standard 2D fluoroscopy was used. The radiation load on the operating surgeon and auxiliary operating personnel was also evaluated. Intraoperative visualization was carried out using the second-generation iNtellect ENT Navigation rack of the Stryker company (United States of America) for the victims of the main array and the Ziehm Vision RFD optical-optical converter (Germany) of the company for the victims of the control group. The imaging option using an electron-optical transducer is especially important for minimally invasive procedures, where instrumentation is performed percutaneously without direct anatomical control, as opposed to open procedures or working with distorted anatomical structures during injuries. Biplanar fluoroscopy was one of the first intraoperative methods of imaging in real time, and remains one of the leading technologies in orthopedic and spinal surgery. However, radiation exposure from intraoperative fluoroscopy remains a serious problem for patients, surgeons, and operating support staff. The negative effect of ionizing radiation leads to cell damage through the induction of deoxyribonucleic acid and the release of reactive oxygen species. In this regard, cell death or genome instability occurs, which leads to various radiation-related pathologies. It was found that the use of neuronavigation reduces the number of errors, reduces intraoperative trauma, and significantly reduces intraoperative radiation exposure to the injured, operating surgeon and auxiliary operating personnel. The large-scale introduction of navigation technologies will reduce or completely eliminate the harmful effects of ionizing radiation on the injured and medical personnel.

Real-time intraoperative 3D image intensifier-based navigation in reversed shoulder arthroplasty- analyses of image quality

BackgroundDue to the high anatomical variability and limited visualization of the scapula, optimal screw placement for baseplate anchorage in reversed total shoulder arthroplasty (rTSA) is challenging. Image quality plays a key role regarding the decision of an appropriate implant position. However, these data a currently missing for rTSA and were investigated in the present study. Furthermore, the rate of required K-wire changes for the central peg as well as post-implantation inclination and version were assessed.MethodsIn ten consecutive patients (8 female, 86 years, range 74–94) with proximal humeral fracture and indication for rTSA, an intraoperative 3D-scan of the shoulder with a 3D image intensifier (Ziehm Vision FD Vario 3D© [Ziehm Imaging GmbH, Nürnberg, Germany]) was performed after resection of the humeral head. Using the Vectorvision© Software (Brainlab AG, Feldkirchen, Germany), the virtual anatomy was compared to the visible anatomical landmarks. After implantation of the baseplate, a 3D scan was performed. All 3D scans included multiplanar reconstruction (MPR) and the cinemode to examine screw and baseplate placement. The rate of required K-wire changes was assessed. The intraoperative 3D image quality (modified visual analogue scale [VAS] and point system) was assessed before and after implantation of the glenoid component. Inclination and version were determined in post-implantation scans.ResultsThe virtually presented anatomical landmarks always correlated to the anatomical visible points indicating an good virtual accuracy. The central K-wire position was corrected in three cases due to a deviation from the face plane technique position. The VAS was higher for the pre-implantation MPR (6.7, range 5–8) compared to the post-implantation acquired MPR (5.1, range 4–6; p = 0.0002). The point system showed a reduced quality in all subcategories, especially regarding the grading of the articular surfaces. The preoperative (7.9, range 6–9) and post-implantation (7.9, range 6–9) cinemode displayed no significant differences (p = 0.6).ConclusionThe present study underlines the need for the improvement of 3D image intensifiers algorithms to reduce artifact associated impaired image quality to enhance the benefit of real-time intraoperative 3D scans and navigation.

3D image acquisition in scoliosis correction surgery: Radiation exposure of a paediatric patient cohort

3D spine imaging has become a popular technique in orthopaedic surgery to assist with the placement of screws and rods for the treatment of scoliosis. It is most often used in combination with navigation software to reduce the risk of surgical-induced patient paralysis. One way to acquire this type of imaging is to use an X-ray c-arm that rotates around the patient, mimicking a cone beam CT acquisition. Although this technique has been successfully implemented in many centres, there is a deficit of information in the literature with regard to the consequent patient radiation exposure, in particular, where an eccentric or non-circular orbit is utilised. This information is particularly important for paediatric patients, as they are the most likely candidates for this type of surgery. Our study estimates the radiation dose to paediatric patients who have undergone scoliosis correction surgery, using the proprietary non-circular orbit employed by a Ziehm Vision RFD 3D C-arm. We estimate and compare patient organ doses using this eccentric orbit with one where a simple circular orbit is assumed. We further compare our calculated organ doses with those imparted by traditional 2D fluoroscopic techniques, and calculate the risk of future radiation induced cancer for this patient cohort. The doses presented here will be useful to other centres in establishing diagnostic reference levels for this increasingly common technique.

Decreased Radiation Exposure with Percutaneous Shielded Lead Compared to Unshielded Implant for Spinal Cord Stimulation

Background: Spinal cord stimulation (SCS) is a safe and effective treatment for refractory failed back surgery syndrome (FBSS). Two implantation procedures exist depending on the use of a surgical versus percutaneous lead. Percutaneous leads implantation is less invasive but the placement procedure requires a higher X-ray exposure. The new MRI compatible shielded percutaneous leads (Vectris®) appear to be stiffer and therefore seem to be easier to implant compared to unshielded percutaneous electrodes (Octad®). The aim of this study is to compare the radiation exposure between percutaneous shielded leads and percutaneous unshielded leads in SCS implantation. Setting: Retrospective study. Material and methods: 20 patients successively underwent SCS for FBSS. The first 10 patients were implanted with an Octad ® lead and the 10 following with a shielded Vectris ® lead. All patients were operated on by the same surgical team. In all cases, the same intra-operative X-rays device (Ziehm Vision 8000®) was used, with identical parameters aiming at a minimal X-rays exposure (pulse mode with 2 impulses/sec, and automatic mode for kVp and mAs). Results: Fluoroscopy time was significantly lower in patients implanted with the Vectris® lead (mean: 99 seconds) compared to the Octad® lead (mean: 291 seconds) (p=0.0035). Subsequently, total patient X-rays exposure in the Vectris group (mean 592 cGycm2) was significantly lower than in the Octad® group (mean: 1899 cGycm2) (p=0.0005). Conclusion: The use of MRI compatible shielded percutaneous leads significantly reduces the fluoroscopy time and the total X-ray exposure in SCS implantation.

Measurements of occupational and patient exposure as well as image quality for two C-arms

Two different C-arms, a Philips Veradius and a Ziehm Vision FD were evaluated with regard to occupational and patient radiation exposure as well as image quality. For this, the scatter radiation, the entrance surface dose rate (ESD rate) and the low contrast detectability (LCD) were evaluated with regard to different examination modes, using phantoms with different thicknesses as well as a Leeds Test Object. The results show a large range of variance between the two systems in relation to the topics investigated. Within comparable modes the Phillips Veradius causes a lower occupational and patient exposure than the Ziehm Vision FD. Furthermore, a lower radiation burden does not necessarily decrease the image quality, and a slight increase in LCD for particular settings is foiled by a big escalation in patient dose.

Navigated versus conventional transfixation of AC joint injuries: Feasibility and accuracy

Objective: Transfixation of the acromioclavicular (AC) joint is a well-established technique for treating Rockwood IV to VI lesions. However, several complications, including pin breakage or pin migration due to incorrect placement, have been reported in the literature. A cadaveric study was performed to investigate whether the use of 3D navigation might improve the accuracy of AC joint transfixation.Methods: Seventeen transfixations of the AC joint (8 non-navigated, 9 navigated) were performed minimally invasively in cadaveric shoulders. For the navigated procedures, a 3D C-arm (Ziehm Vision FD Vario 3D) and a navigation system (BrainLab VectorVision) were used. Reference markers were attached to the spina scapulae, then a 3D scan was performed and the data transferred to the navigation system. Two Kirschner wires (K-wires) were placed either freehand under fluoroscopic control (in the non-navigated group) or with the use of a navigated drill guide. Radiological analysis was performed with OsiriX software, measuring the distance of the K-wires from the center of the AC joint. For statistical analysis, Student's t-test was performed, with the significance level being set to p < 0.05.Results: The maximum distance of the K-wires from the center of the AC joint was 5.4 ± 1.1 mm for the freehand non-navigated group and 3.1 ± 1.6 mm for the navigated group (p = 0.0054). The minimum distance of the K-wires from the AC joint center was 3.0 ± 0.6 mm for the freehand group and 1.6 ± 0.6 mm for the navigated group (p = 0.0002). The radiation time was significant lower for the freehand group (41.25 ± 20.4 seconds versus 79.5 ± 13.3 seconds for the navigated group, p = 0.004). There was no statistical difference between the groups with respect to the time required for surgery (11.25 ± 3.6 min for the freehand group and 12.6 ± 4.6 min for the navigated group; p = 0.475). In the freehand group, the AC joint was penetrated by both K-wires in 87.5% of the procedures, compared to 100% in the navigated group. Both K-wires were placed completely intraosseously in the clavicula in 50% of the procedures in the freehand group, compared to 88% in the navigated group.Conclusion: Three-dimensional navigation may improve the accuracy of AC joint transfixation techniques. However, the radiation time is increased when using the navigated procedure, while the overall operation time remains comparable. Nevertheless, a 3D C-arm with a variable isocentric design is recommended for the acquisition of the shoulder scans.

Image quality of two different mobile cone beam computed tomographs for maxillofacial surgery

PurposeWe evaluated two mobile cone beam computed tomographs (mCBCT) comparing image quality with respect to radiation dosage. Image quality was analyzed by using different scanning modes. Materials and methodsThe skulls of three human cadavers were scanned by use of conventional Computed Tomography (CT) as well as with two mobile cone beam computed tomographs (Siemens Arcadis Orbic 3D and Ziehm Vision Vario 3D). Six different acquisition modes with different radiation dosages were used. The axial views of all scans were evaluated by five medical doctors regarding image quality by identifying predefined anatomical structures of the skull. A five-point ranking scale was used. The inter-rater reliability was statistically depicted by Cohen’s Kappa coefficient. A Wilcoxon signed rank test was used to evaluate the rater’s results. For evaluating the signal-to-noise ratio (SNR) a Catphan 600 reference body with two different inlays was used. ResultsComparing the mCBCTs, the image quality of the Siemens Arcadis Orbic 3D in high-dosage mode received the best score (median: 2.27). The inter-rater reliability was fair (Kappa=−0.030 to 0.328). The Wilcoxon test showed significant (p<0.05) different median rating values in 18 out of 21 imaging modes. The SNR was higher (better) in the high-dosage modes. ConclusionIntra-operative 3D imaging by using mCBCT for maxillofacial surgery in low-dose mode acquisition is adequate in terms of signal-to-noise ratio and image quality. The image quality does not correlate in a linear manner with a higher radiation dosage. Surgeons using this technique should gather their own experience with the different acquisition modes.

Vergleich der Bildqualität zweier unterschiedlicher mobiler 3-dimensionaler Röntgen-C-Bögen mit einem konventionellen CT bei der Darstellung relevanter Strukturen am knöchernen Becken

This study evaluated the image quality of two different cone beam CT scanners used in the operation theatre in pelvic trauma surgery in relation to their radiation dosage. Furthermore, the assumption that a higher dosage would result in better image quality was analysed by using the different acquisition scanner modes. We scanned the acetabulum (n=4) and iliosacral joints (n=4) of two human cadavers with a conventional CT and with two mobile cone beam CT scanners (Siemens Arcadis Orbic 3D and Ziehm Vision Vario 3D). With the two cone beam CT scanners (3D-BV), we used 6 different acquisition modes with different radiation dosages. The axial views of all scans were exported and blinded. Subsequently, the images were evaluated by 7 medical doctors with regard to identifiability of cortical structures (acetabular joint, fovea capitis femoris, cortical bone of the femur head, iliosacral joint, and sacral foramina), and the quality of the cancellous structure of the femur head. The evaluation was performed on axial views by using a defined five-point score. The interrater quality was statistically analysed according to Cohen with the kappa coefficient. In addition, the Wilcoxon test was used to identify significances between the 21 paired results of the evaluators. For determination of the signal-to-noise ratio, a Catphan 600 reference block with two different test elements (Teflon, PMP) was used. Overall, the image quality of the conventional CT scans received the best score. Comparing the two 3D cone beams, the image quality of the Siemens Arcadis Orbic 3D in high-dosage mode received the best score (median: 2.40), the Ziehm Vision Vario 3D in low-dose mode without large patient key received the lowest score (median: 3.16). The differences in the 21 paired results of the two different acquisition modes were significant in 17 cases (p < 0.05) but the size of difference when comparing the different acquisition modes was almost always small. The interobserver agreement in one acquisition mode was low (kappa 0.008-0.134). The overall evaluation results of the same acquisition mode diverged by up to 2 score points. We noted a higher signal-to-noise ratio in the high dosage mode than in the low dosage mode. When using intraoperative 3D imaging with the cone beam CT technique for pelvic injury, image acquisition in low-dose mode is adequate in terms of signal-to-noise ratio and image quality. The image quality does not correlate linearly with a higher radiation dosage. Therefore, the pelvic trauma surgeon using this technique is encouraged to gather his own experience with low dose modes thereby reducing patient radiation exposure.

3D-based navigation in posterior stabilisations of the cervical and thoracic spine: problems and benefits. Results of 451 screws.

Navigated procedures in spinal surgery have been established due to an increasing demand for precision. Especially, 3D C-arms connected to navigation systems are being used more often and can be utilised intraoperatively for the planning and controlling of screw positions. This prospective study analyses our experiences with 3D-based navigation in posterior stabilisations in the cervical and thoracic spine. A 3D C-Arm (Ziehm Vision Vario 3D(®)) was connected to a navigation system (VectorVision, Brainlab(®)) and used for the placement of, in total, 451 screws among 67 patients. Of those, 14 patients had to undergo operations in the cervical and 53 in the thoracic spine. Postoperatively, the positioning was observed with computed tomography (CT). The application time is approximately 6min. In total, 354/451 (78.5%) screws could be inserted assisted with navigation, and 272/451 (60.3%) were controlled intraoperatively. Regarding the cervical spine, in 87.1% (61/70) of the screws, the navigation procedure was uneventful. The positioning of 63.2% (43/68) of the screws was checked intraoperatively. In the upper thoracic spine, 77% (293/381) could be placed with navigation and 59.6% (227/381) were controlled intraoperatively. Occasionally, the scanning setup was problematic. Correct placement was seen in 92.7% of screws; for the remaining screws, no revision was needed. Intraoperative 3D imaging navigation for posterior spinal stabilisations is technically feasible and reliable in clinical use. The image quality depends on the individual bone density. With undisturbed visibility of the vertebral body, the reliability of 3D-based navigation is comparable to that of CT-based procedures. Additionally, it has the advantage of skipping the preoperative acquisition of data as well as the matching process, with reduced radiation doses.

Measurement of an intact knee kinematics using gait and fluoroscopic analysis

A method has been introduced in this paper to measure the kinematics of a knee joint and to use it as a boundary condition to model the knee's mechanical behaviour. A mobile C-Arm fluoroscopy system (Ziehm Vision R) and a CCD camera were used for the measurement of a patient's knee kinematics. The fluoroscopic images were recorded with 12fps and then sent to Matlab software (Mathworks, Natick, MA, USA) for image processing. In parallel, CT scan images of the knee bones were used to create the 3D anatomical geometry of the knee by aid of Mimics software (Materialise NV). However, the geometrical model of the two medial and lateral menisci was generated from MRI data. The 3D geometrical model of the knee was then sent to Abaqus finite element software (Simulia Dassault Systems) to analyse the knee joint contact loads by introducing the boundary condition which was obtained from fluoroscopic images. The finite element model was used to evaluate the stress distribution on the cartilages during the gait. The result was then compared with the experimental data of gait analysis. The comparison between the results showed a close agreement between the two outcomes.

Navigated minimally invasive thoracolumbar pedicle screw placement with flat panel 3-D imaging. A feasibility study

The current study involves a cadaveric specimen with navigated pedicle screw placement using conventional reference markers and isocentric 3D fluoroscopy and also minimally invasive reference marker use with a flat panel 3D scanner. To test the feasibility of a novel minimally invasive reference marker system for navigated pedicle screw placement in combination the use of a new imaging modality i.e. flat panel 3D imaging. A major limiting factor of navigated pedicle screw placement is the requirement for intraosseous fixation of reference markers. This usually necessitates an open approach to the spinous process. To address this issue, the current authors have developed a minimally-invasive fixation device for spinal reference marker fixation. A fresh-frozen cadaver with no history of spinal injury or deformity was positioned prone on a radiolucent table. L3 and L4 vertebrae were randomly selected for conventional pedicle screw insertion while T5 and T6 were selected for the percutaneous technique. A flat detector 3D C-arm (Ziehm vision FD 3D; Ziehm, Nuremberg, Germany) was used to evaluate the position of the pedicle screws at the vertebral levels targeted in the study. All screws placed within the lumbar spine involved conventional reference markers. The average depth deviation was 0.73 mm and the average axis deviation was 1.67 mm. Within the thoracic spine, the minimally-invasive marker fixation devices were used. The average depth deviation was 0.85 mm and the average axis deviation was 1.75 mm. In both cases, the plan and navigation were performed satisfactorily. The Y-jaw clamp for minimally-invasive reference fixation seemed to provide stable and robust fixation of the markers, requiring only two small incisions. The minimally invasive reference marker system produced results which were comparable to the conventional intra-osseous markers while the flat detector-based navigation was shown to be easier to use and faster than isocentric Iso-3D technology.