Fluoroscopic System Research Articles

Effects of Barefoot and Shod on the In Vivo Kinematics of Medial Longitudinal Arch During Running Based on a High-Speed Dual Fluoroscopic Imaging System.

Shoes affect the biomechanical properties of the medial longitudinal arch (MLA) and further influence the foot’s overall function. Most previous studies on the MLA were based on traditional skin-marker motion capture, and the observation of real foot motion inside the shoes is difficult. Thus, the effect of shoe parameters on the natural MLA movement during running remains in question. Therefore, this study aimed to investigate the differences in the MLA’s kinematics between shod and barefoot running by using a high-speed dual fluoroscopic imaging system (DFIS). Fifteen healthy habitual rearfoot runners were recruited. All participants ran at a speed of 3 m/s ± 5% along with an elevated runway in barefoot and shod conditions. High-speed DFIS was used to acquire the radiographic images of MLA movements in the whole stance phase, and the kinematics of the MLA were calculated. Paired sample t-tests were used to compare the kinematic characteristics of the MLA during the stance phase between shod and barefoot conditions. Compared with barefoot, shoe-wearing showed significant changes (p < 0.05) as follows: 1) the first metatarsal moved with less lateral direction at 80%, less anterior translation at 20%, and less superiority at 10–70% of the stance phase; 2) the first metatarsal moved with less inversion amounting to 20–60%, less dorsiflexion at 0–10% of the stance phase; 3) the inversion/eversion range of motion (ROM) of the first metatarsal relative to calcaneus was reduced; 4) the MLA angles at 0–70% of the stance phase were reduced; 5) the maximum MLA angle and MLA angle ROM were reduced in the shod condition. Based on high-speed DFIS, the above results indicated that shoe-wearing limited the movement of MLA, especially reducing the MLA angles, suggesting that shoes restricted the compression and recoil of the MLA, which further affected the spring-like function of the MLA.

Distal Humeral Trochlear Geometry Associated With the Spatial Variation of the Dynamic Elbow Flexion Axis.

Background: The complexity of the spatial dynamic flexion axis (DFA) of the elbow joint makes the elbow prosthesis design and humeral component alignment challenging. This study aimed to 1) investigate the variations of the spatial DFA during elbow flexion and 2) investigate the relationship between the distal humeral trochlear geometry and the in vivo spatial variation of the DFA. Methods: Ten healthy subjects participated in this study. Each subject performed a full elbow extension to maximum flexion with hand supination under dual fluoroscopic imaging system (DFIS) surveillance. The 2D fluoroscopic images and the 3D bone models were registered to analyze the in vivo elbow kinematics and DFAs. The spatial DFA positions were defined as inclination with the medial and lateral epicondyle axes (MLA) in the transverse and coronal planes. The range of the DFA positions was also investigated during different flexion phases. The Spearman correlation method was used to analyze the relationship between the distal humeral trochlear’s morphological parameters and the position of DFAs during different flexion phases. Results: The pathway of the DFAs showed an irregular pattern and presented individual features. The medial trochlear depth (MTD) (r = 0.68, p = 0.03) was positively correlated with the range of the DFA position (2.8° ± 1.9°) in the coronal plane from full extension to 30° of flexion. Lateral trochlear height (LTH) (r = −0.64, p = 0.04) was negatively correlated with the DFA position (−1.4° ± 3.3°) in the transverse plane from 30° to 60° of flexion. A significant correlation was found between LTH with the DFA position in the coronal (r = −0.77, p = 0.01) and transverse planes (r = −0.76, p = 0.01) from 60° to 90° of flexion. Conclusion: This study showed that the pathway of the dynamic flexion axis has an individual pattern. The medial and lateral trochlear sizes were the key parameters that might affect the elbow joint flexion function. When recovering complex distal humeral fractures or considering the implant design of total elbow arthroplasty, surgeons should pay more attention to the medial and lateral trochlea’s geometry, which may help restore normal elbow kinematics.

Use of a Lightweight Portable Fluoroscopy Device for Obtaining Weightbearing Ankle Images

Portable fluoroscopy devices provide point-of-care imaging in emergency and out-patient clinics. In this prospective study, we compared weightbearing images of syndesmosis obtained using a novel lightweight portable battery-powered fluoroscopy device with those obtained with a conventional radiography device. Eleven healthy participants underwent bilateral 3-view weightbearing imaging of both ankles using a radiography (X-ray group) device and a portable fluoroscopy system (LPF group). Anteroposterior, mortise, and lateral views were compared between the 2 techniques. Radiographic measurements were done by 2 observers. These measurements included talar tilt, tibiofibular clear space, tibiofibular overlap, plafond malleolar angle, medial distal tibial angle, medial clear space, lateral distal tibial angle, anterior and posterior tibiofibular distance were measured using the appropriate view. Data were compared between the 2 techniques; the interobserver agreement was calculated within each group. P < .05 was considered statistically significant. Comparing the 2 imaging modalities, there was no significant difference between the measurements in LPF and X-ray groups except plafond malleolar angle. The overall interobserver agreement was excellent between the 2 observers. There was no significant difference between the measures by the 2 observers and between the bilateral ankles. Fluoroscopy was associated with about 50% extra radiation exposure, although the absolute amount of radiation was not clinically significant. These results support the use of weightbearing images using portable fluoroscopy device as an alternative for the conventional radiography systems.

Influence of Shod and Barefoot Running on the In Vivo Kinematics of the First Metatarsophalangeal Joint.

The biomechanics of the first metatarsophalangeal joint (MTPJ) is affected by different shoe conditions. In the biomechanical research field, traditional skin marker motion capture cannot easily acquire the in vivo joint kinematics of the first MTPJ in shoes. Thus, the present study aims to investigate the differences of the first MTPJ’s six-degree-of-freedom (6DOF) kinematics between shod and barefoot running by using a high-speed dual fluoroscopic imaging system (DFIS). In total, 15 healthy male runners were recruited. Computed tomography scans were taken from each participant’s right foot for the construction of 3D models and local coordinate systems. Radiographic images were acquired at 100 Hz while the participants ran at a speed of 3 m/s ± 5% in shod and barefoot conditions along an elevated runway, and 6DOF kinematics of the first MTPJ were calculated by 3D–2D registration. Paired sample t-tests were used to compare the kinematic characteristics of the first MTPJ 6DOF kinematics during the stance phase between shod and barefoot conditions. Compared with barefoot, wearing shoes showed significant changes (p < 0.05): 1) the first MTPJ moved less inferior at 50% but moved less superior at 90 and 100% of the stance phase; 2) the peak medial, posterior, and superior translation of the first MTPJ significantly decreased in the shod condition; 3) the extension angle of the first MTPJ was larger at 30–60% but smaller at 90 and 100% of the stance phase; 4) the maximum extension angle and flexion/extension range of motion of the first MTPJ were reduced; and 5) the minimum extension and adduction angle of the first MTPJ was increased in the shod condition. On the basis of the high-speed DFIS, the aforementioned results indicated that wearing shoes limited the first MTPJ flexion and extension movement and increased the adduction angle, suggesting that shoes may affect the propulsion of the first MTPJ and increase the risk of hallux valgus.

Skull‐Brain Biomechanics of Headbutting. An XROMM Pilot Study on Goats

In humans, the coup‐contrecoup injury occurs opposite the site of impact when the brain meets the skull, causing intracerebral hemorrhage. It makes up a significant portion of traumatic brain injuries (TBI) and can often lead to neurodegeneration. Bighorn sheep and related bovids are known for their impressive headbutting rituals performed during the rut, the general belief being that these animals come away unharmed from these encounters. However, a recent immunohistochemical study revealed TBI in bighorn sheep and muskoxen in relation to headbutting. With a large gyrencephalic brain, repetitive headbutting, and a pathology pattern resembling early chronic traumatic encephalopathy in humans, bovids present themselves as a significant model for TBI. It is, however, uncertain whether bovids sustain coup‐contrecoup injury due to the oblong shape of their braincase and tight fit to the brain. We aimed to investigate whether cranial and neuroanatomical aspects of the bovid head anatomy contribute to TBI reduction, using goats as a model to measure brain movement independent of the skull upon impact.Four cadaveric goat heads were implanted with radiodense tantalum beads in the skull and brain. A weight‐drop system was used to create an impact within the field of view of a biplanar fluoroscopy system. The heads were CT scanned and the recording was reconstructed as an animated 3D model using x‐ray reconstruction of moving morphology (XROMM). The brain markers were tracked relative to each other to account for soft tissue deformation and marker migration and relative to the skull markers to account for brain movement. We were able to visualize how the brain moves in relation to the skull for the first time in bovids, providing a better understanding of skull‐brain biomechanics.

V03-03 ULTRA-LOW-DOSE INTRAOPERATIVE CT IMAGING DURING PCNL

You have accessJournal of UrologyCME1 May 2022V03-03 ULTRA-LOW-DOSE INTRAOPERATIVE CT IMAGING DURING PCNL Xavier Glover, Eric Ballon-Landa, and Mark Sawyer Xavier GloverXavier Glover More articles by this author , Eric Ballon-LandaEric Ballon-Landa More articles by this author , and Mark SawyerMark Sawyer More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002539.03AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Intraoperative CT scan in a hybrid room environment during PCNL has been described internationally to aid in obtaining percutaneous access or to assess for residual stones. The initial description of using a robotic-armed fluoroscopy system (Artis Zeego, Siemens) to assess for residual stones, and then to confirm stone free status, was by Vincentini et al. in 2017. Van den Broek, et al. described the use of intraoperative CT scan during PCNL in a prospective study of 20 patients with a median intraoperative CT scan dose of 6.7 mSv. Our group is the first to report ultra-low-dose (<2 mSv) intraoperative CT scans during PCNL/ECIRS. METHODS: This video demonstrates the technical factors involved in performing supine PCNL/ECIRS. We demonstrate how the Artis Zeego robotic biplane fluoroscopy platform was used to achieve ultra-low-dose intraoperative imaging in a hybrid operating room environment. Intraoperative CT scans are performed using a combination of low-dose protocols and imaging collimation to the level of the kidney to achieve extraordinarily low radiation exposures for patients and clinicians. PCNLs with intraoperative CT imaging are performed as part of an IRB-approved prospective QI study intended to maximize likelihood of complete stone treatment and to reduce radiation exposure. RESULTS: We have successfully ensured stone-free status in kidney stone patients undergoing PCNL/ECIRS by obtaining intraoperative CT imaging. In cases where residual stone is identified and successfully treated, a second scan is then routinely performed. This video demonstrates the first international experience with ultra-low dose intraoperative CT scan. Median intraoperative CT scan dose to date is only 1 mSv. This is 93% lower than the average post-PCNL CT scan performed at our facility (13.6 mSv). To date, we have achieved a total intraoperative effective dose (including standard fluoroscopy) as low as 1.11 mSv. This single-stage treatment of a 2.1 cm kidney stone included percutaneous access by the urologist, routine fluoroscopy, and an intraoperative CT scan that confirmed no residual fragments. CONCLUSIONS: This video has documented the first international experience for ultra-low-dose intraoperative imaging during PCNL. Effective doses are sufficiently low that multiple scans can be obtained, while still achieving significantly lower total dosage than with standard post-operative imaging. Our study is ongoing with the intent to further decrease total radiation exposure related to stone surgery. Source of Funding: None © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e201 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information Xavier Glover More articles by this author Eric Ballon-Landa More articles by this author Mark Sawyer More articles by this author Expand All Advertisement PDF DownloadLoading ...

3D orientation and kinematic characteristics of zygapophyseal joints while sitting.

BackgroundOrientation of the lumbar facet joints (FJs) in the transverse plane is associated with degenerative lumbar spine disease. However, there is a lack of measurements of the sagittal and coronal facet angles, and the effect of 3D facet angles on joint motion in the sitting position is unknown. The present study was to investigate the 3D orientation and in vivo motion characteristics of the FJ in the sitting position.MethodsDual fluoroscopic imaging system and computed tomography (CT) were used to determine the 3D orientation and kinematic characteristics of FJs. L3-S1 segments were studied in 10 asymptomatic participants (5 male and 5 female, age: 25–35 years, body mass index: 22.4±1.8). Angles of the facet in the sagittal, coronal, and axial planes, and the range of motion of the FJs in seated flexion and extension movements were measured.ResultsThe difference in sagittal facet angles between the 2 sides of the L3-S1 facet joints was not significant. The superior coronal facet angle on the left side of L5 was significantly smaller than that on the right side by 6.4° (P=0.01). The inferior transverse facet angle on the left side of L5 was greater than that on the right side by 7.1; the results were not statistically significantly different. In the sitting position, the range of motion of the left and right sides of L5-S1 differed significantly, with the right side being 5.5° (P=0.004) and 11.7° (P=0.026) greater than the left side in the sagittal and coronal planes, respectively. There was a correlation between mobility and the 3D orientation angle of the FJs in each segment.ConclusionsQuantification of the 3D orientation of the lumbar spine FJs provides new perspectives to study the kinematics of the lumbar spine and the etiology of lumbar degenerative diseases. In sitting flexion and extension movements, there is a significant difference in the left-right lateral mobility of the FJs of the L5-S1 segments. With the exception of the transverse facet angle of the lumbar spine FJs, the sagittal and coronal facet angles also have an effect on lumbar spine mobility.

Effect of loading history on material properties of human heel pad: an in-vivo pilot investigation during gait

BackgroundThis study was aimed to develop a novel dynamic measurement technique for testing the material properties and investigating the effect of continuous compression load on the structural and mechanical properties of human heel pad during actual gait.MethodsThe dual fluoroscopic imaging system (DFIS) and dynamic foot-ground contact pressure-test plate were used for measuring the material properties, including primary thickness, peak strain, peak stress, elastic modulus, viscous modulus and energy dissipation rate (EDR), both at time zero and following continuous loading. Ten healthy pilot subjects, aged from 23 to 72 (average: 46.5 ± 17.6), were enrolled. A “three-step gait cycle” is performed for all subjects, with the second step striking at a marked position on the force plate with the heel to maintain the location of the tested foot to be in the view of fluoroscopes. The subjects were measured at both relaxed (time-zero group) and fatigue (continuous-loading group) statuses, and the left and right heels were measured using the identical procedures.ResultsThe peak strain, peak stress, elastic modulus, and EDR are similar before and after continuous load, while the viscous modulus was significantly decreased (median: 43.9 vs. 20.37 kPa•s; p < 0.001) as well as primary thicknesses (median: 15.99 vs. 15.72 mm; p < 0.001). Age is demonstrated to be moderately correlated with the primary thicknesses both at time zero (R = -0.507) and following continuous load (R = -0.607). The peak stress was significantly correlated with the elastic modulus before (R = 0.741) and after continuous load (R = 0.802). The peak strain was correlated with the elastic modulus before (R = -0.765) and after continuous load (R = -0.801). The correlations between the viscous modulus and peak stress/ peak strain are similar to above(R = 0.643, 0.577, − 0.586 and − 0.717 respectively). The viscous modulus is positively correlated with the elastic modulus before (R = 0.821) and after continuous load (R = 0.784).ConclusionsBy using dynamic fluoroscopy combined with the plantar pressure plate, the in vivo viscoelastic properties and other data of the heel pad in the actual gait can be obtained. Age was negatively correlated with the primary thickness of heel pad and peak strain, and was positively correlated with viscous modulus. Repetitive loading could decrease the primary thickness of heel pad and viscous modulus.

Investigation of geometric deformations of the lumbar disc during axial body rotations

BackgroundQuantitative data on in vivo vertebral disc deformations are critical for enhancing our understanding of spinal pathology and improving the design of surgical materials. This study investigated in vivo lumbar intervertebral disc deformations during axial rotations under different load-bearing conditions.MethodsTwelve healthy subjects (7 males and 5 females) between the ages of 25 and 39 were recruited. Using a combination of a dual fluoroscopic imaging system (DFIS) and CT, the images of L3–5 segments scanned by CT were transformed into three-dimensional models, which matched the instantaneous images of the lumbar spine taken by a double fluorescent X-ray system during axial rotations to reproduce motions. Then, the kinematic data of the compression and shear deformations of the lumbar disc and the coupled bending of the vertebral body were obtained.ResultsRelative to the supine position, the average compression deformation caused by rotation is between + 10% and − 40%, and the shear deformation is between 17 and 50%. Under physiological weightbearing loads, different levels of lumbar discs exhibit similar deformation patterns, and the deformation patterns of left and right rotations are approximately symmetrical. The deformation patterns change significantly under a 10 kg load, with the exception of the L3–4 disc during the right rotation.ConclusionThe deformation of the lumbar disc was direction-specific and level-specific during axial rotations and was affected by extra weight. These data can provide new insights into the biomechanics of the lumbar spine and optimize the parameters of artificial lumbar spine devices.

Patient radiation dose during angiography and embolization for abdominal hemorrhage: the influence of CT angiography, fluoroscopy system, patient and procedural variables

BackgroundAngiography and embolization (AE) is a lifesaving, high radiation dose procedure for treatment of abdominal arterial hemorrhage (AAH). Interventional radiologists have utilized pre-procedure CT angiography (CTA) and newer fluoroscopic systems in an attempt to reduce radiation dose and procedure time.PurposeTo study the factors contributing to the radiation dose of AE for AAH and to compare to the reference standard.Materials and methodsThis retrospective single-centre observational cohort study identified 154 consecutive AE procedures in 138 patients (median age 65 years; interquartile range 54–77; 103 men) performed with a C-arm fluoroscopic system (Axiom Artis DTA or Axiom Artis Q (Siemens Healthineers)), between January 2010 and December 2017. Parameters analysed included: demographics, fluoroscopy system, bleeding location, body mass index (BMI), preprocedural CT, air kerma-area product (PKA), reference air kerma (Ka,r), fluoroscopy time (FT) and the number of digital subtraction angiography (DSA) runs. Factors affecting dose were assessed using Mann–Whitney U, Kruskal–Wallis one-way ANOVA and linear regression.ResultsPatients treated with the new angiographic system (NS) had a median PKA, median Ka,r, Q3 PKA and Q3 Ka,r that were 74% (p < 0.0005), 66%(p < 0.0005), 55% and 52% lower respectively than those treated with the old system (OS). This dose reduction was consistent for each bleeding location (upper GI, Lower GI and extraluminal). There was no difference in PKA (p = 0.452), Ka,r (p = 0.974) or FT (p = 0.179), between those who did (n = 137) or did not (n = 17) undergo pre-procedure CTA. Other factors significantly influencing radiation dose were: patient BMI and number of DSA runs. A multivariate model containing these variables accounts for 15.2% of the variance in Ka,r (p < 0.005) and 45.9% of the variance of PKA (p < 0.005).ConclusionRadiation dose for AE in AAH is significantly reduced by new fluoroscopic technology. Higher patient body mass index is an independent key parameter affecting patient dose. Radiation dose was not influenced by haemorrhage site or performance of pre-procedure CTA.

Cartilage contact characteristics of the knee during gait in individuals with obesity.

Obesity increases the risk of knee osteoarthritis (OA). Knee joint contact characteristics have been thought to provide insights into the pathogenesis of knee OA; however, the cartilage contact characteristics in individuals with obesity have not been fully described. We conducted cartilage-to-cartilage contact analyses through high-precision fluoroscopy imaging with subject-specific magnetic resonance cartilage models. Twenty-five individuals with obesity were recruited for this study, and previously published data consisted of eight nonobese individuals who were used as the comparator group. In both groups, knees were imaged by a dual fluoroscopic imaging system during treadmill walking, and the tibiofemoral cartilage contact locations were analyzed and described on the tibial plateau in the medial-lateral (ML) and anterior-posterior (AP) directions and on femoral condyle surfaces using contact angles in the sagittal plane and deviation angles in a plane perpendicular to the sagittal plane. On the medial tibial plateau, the ML contact locations in the individuals with obesity were located more medially than in the nonobese group throughout the stance phase. The medial plateau AP contact locations in individuals with obesity showed a different pattern compared with the nonobese group. The ML contact excursions on the medial plateau in the individuals with obesity were larger than in the nonobese group. These findings suggest that obesity affects the contact location mainly in the medial compartment, which explains, in part, the high prevalence of medial knee OA in the obese population.

Three-Dimensional Innate Mobility of the Human Foot on Coronally-Wedged Surfaces Using a Biplane X-Ray Fluoroscopy.

Improving our understanding on how the foot and ankle joints kinematically adapt to coronally wedged surfaces is important for clarifying the pathogenetic mechanism and possible interventions for the treatment and prevention of foot and lower leg injuries. It is also crucial to interpret the basic biomechanics and functions of the human foot that evolved as an adaptation to obligatory bipedal locomotion. Therefore, we investigated the three-dimensional (3D) bone kinematics of human cadaver feet on level (0°, LS), medially wedged (−10°, MWS), and laterally wedged (+10°, LWS) surfaces under axial loading using a biplanar X-ray fluoroscopy system. Five healthy cadaver feet were axially loaded up to 60 kg (588N) and biplanar fluoroscopic images of the foot and ankle were acquired during axial loading. For the 3D visualization and quantification of detailed foot bony movements, a model-based registration method was employed. The results indicated that the human foot was more largely deformed from the natural posture when the foot was placed on the MWS than on the LWS. During the process of human evolution, the human foot may have retained the ability to more flexibly invert as in African apes to better conform to MWS, possibly because this ability was more adaptive even for terrestrial locomotion on uneven terrains. Moreover, the talus and tibia were externally rotated when the foot was placed on the MWS due to the inversion of the calcaneus, and they were internally rotated when the foot was placed on the LWS due to the eversion of the calcaneus, owing to the structurally embedded mobility of the human talocalcaneal joint. Deformation of the foot during axial loading was relatively smaller on the MWS due to restricted eversion of the calcaneus. The present study provided new insights about kinematic adaptation of the human foot to coronally wedged surfaces that is inherently embedded and prescribed in its anatomical structure. Such detailed descriptions may increase our understanding of the pathogenetic mechanism and possible interventions for the treatment and prevention of foot and lower leg injuries, as well as the evolution of the human foot.

Minimally trained analysts can perform fast, objective assessment of orthopedic technical skill from fluoroscopic images

Skill assessment in orthopedics has traditionally relied on subjective impressions from a supervising surgeon. The feedback derived from these tools may be limited by bias and practical issues. Objective analysis of intraoperative fluoroscopic images offers an inexpensive and easily repeatable assessment strategy without bias. Despite the advantages, surgeon mentors generally refrain from using the scores of images obtained throughout an operation to evaluate a performer’s technical skill because of other practical constraints. A new system was designed to rapidly facilitate objective analysis of fluoroscopy using minimally trained analysts. Four expert and four novice analysts independently measured one objective metric of orthopedic technical skill using both a custom analysis software and a commercial alternative. Novice analysts using the custom software produced measurements three times faster than experts using the commercial software without a practical difference in annotation error. Expert analysts leveraged the custom software automation features to further improve their measurements. These results suggest that a well-designed fluoroscopy analysis system can facilitate regular, practical, and objective assessment of orthopedic technical skill.

Review and investigation of automatic brightness/dose rate control logic of fluoroscopic imaging systems in cardiovascular interventional angiography.

In this article, we review automatic brightness control (ABC) for fluoroscopy imaging systems. Starting from the simple manual control, the discussion is extended to the kV-primary ABC system, and then to the most recent contrast-to-noise ratio optimized (CNR Optimized) automatic dose rate control system (ADRC). The nature of this review article is trifold. First, it describes the ABC/ADRC and associated circuits governing the operation of the fluoroscopy imaging chain. Second, we show the characteristics of a control logic from a radiation physics point of view. Third, we introduce the most recent activities in the evaluation of CNR-optimized fluoroscopy systems and the phantom design that would be compatible with the design concept of the ADRC. Because of these three subject items in the discussion process, this article is also educational in nature written for medical physicists and radiological technologists who might be less familiar with the design concept of fluoroscopy operation, specifically on the ABC and ADRC. We insert a few related matters associated with fluoroscopy automatic control circuits where they seem applicable and appropriate to enhance the understanding of fluoroscopy operation logic.

Accuracy Evaluation of Air Kerma-area Product of Over-couch-type X-ray Fluoroscopic System

The purpose of this study was to evaluate the accuracy of incident air kerma (Ka,r) and air kerma-area product (PKA) displayed on over-couch-type X-ray fluoroscopic systems by comparing them with the measured values. An ionizing chamber was placed at the patient entrance reference point to measure the Ka,r. The PKA was calculated by multiplying the Ka,r by the irradiation area. These measured values were compared with the displayed values. The differences between measured and displayed Ka,r and PKA were less than ±35%, which was the criteria of the Japanese Industrial Standards (JIS). However, the accuracy of the displayed values differed depending on the manufacturer and the device. Although no error exceeding the JIS criteria was observed, it is necessary to understand the characteristics of the X-ray fluoroscopic systems related to displayed dose and to manage the systems by performing dose measurements periodically.

Characterisation of hemidiaphragm dysfunction using dynamic chest radiography: a pilot study.

ObjectivesDynamic chest radiography (DCR) is a novel real-time digital fluoroscopic imaging system that produces clear, wide field-of-view diagnostic images of the thorax and diaphragm in motion, alongside novel metrics on moving structures within the thoracic cavity. We describe the use of DCR in the measurement of diaphragm motion in a pilot series of cases of suspected diaphragm dysfunction.MethodsWe studied 21 patients referred for assessment of diaphragm function due to suspicious clinical symptoms or imaging (breathlessness, orthopnoea, reduced exercise tolerance and/or an elevated hemidiaphragm on plain chest radiograph). All underwent DCR with voluntary sniff manoeuvres.ResultsParadoxical motion on sniffing was observed in 14 patients, and confirmed in six who also underwent fluoroscopy or ultrasound. In four patients, DCR showed reduced hemidiaphragm excursion, but no paradoxical motion; in three, normal bilateral diaphragm motion was demonstrated. DCR was quick to perform, and well tolerated in all cases and with no adverse events reported. DCR was achieved in ∼5 min per patient, with images available to view by the clinician immediately within the clinical setting.ConclusionDCR is a rapid, well-tolerated and straightforward chest radiography technique that warrants further investigation in the assessment of diaphragm dysfunction.

Hybrid Room: Does it Offer Better Accuracy in the Proximal Deployment of Infrarenal Aortic Endograft?

This work aims to evaluate the impact of hybrid rooms and their advanced tools on the accuracy of proximal deployment of infrarenal bifurcated endograft (EVAR). A retrospective single center analysis was conducted between January 2015 and March 2019 including consecutive patients that underwent EVAR. Groups were defined whether the procedure was performed in a hybrid operating room (HOR group) or using a mobile 2D fluoroscopic imaging system (non-HOR group). The accuracy of the proximal deployment was estimated by the distance (mm) between the bottom of the lowest renal artery (LwRA) origin and the endograft radiopaque markers parallax (LwRA/EDG distance) after curvilinear reconstruction. The impact of HOR on the LwRA/EDG distance was investigated using a multiple linear regression model. A composite "proximal neck"-related complications event was studied (Cox models). Overall, 93 patients (87 %male, median age 73 years) were included with 49 in the HOR group and 44 in the non-HOR group. Preoperative CTA analysis of the proximal neck exhibited similar median length, but different median aortic diameter (P=0.012) and median beta angulation (P=0.027) between groups. The median LwRA/EDG distance was shorter in the HOR group (multivariate model, P=0.022). No difference in "proximal neck"-related complications was evidenced between the HOR and non-HOR groups (univariate analysis, P=0.620). Median follow-up time was respectively 25 [14-28] and 36 months [23-44] in the HOR group and in the non-HOR group (P < 0.001). HOR offer more accurate proximal deployment of infrarenal endografts, with however no difference in "proximal neck"-related complications between groups.

A novel method to assess the spatiotemporal image quality in fluoroscopy

Objectives. The planar formulation of the noise equivalent quanta (NEQ) and detective quantum efficiency (DQE) used to assess the image quality of projection images does not deal with the influence of temporal resolution on signal blurring and image noise. These metrics require correction factors based on temporal resolution when used for dynamic imaging systems such as fluoroscopy. Additionally, the standard NEQ and detector DQE are determined on pre-processed images in scatter-free conditions for effective energies produced by additional aluminium or copper filters that are not representative of clinical fluoroscopic procedures. In this work, we developed a method to measure ‘frame NEQ’ and ‘frame system DQE’ which include the temporal frequency bandwidth and consider the anti-scatter grid, the detector and the image processing procedures for beam qualities with scatter fractions representative of clinical use. Approach. We used a solid water phantom to simulate a patient and a thin copper disc to measure the spatial resolution. The copper disc, set in uniform rectilinear motion in the image plane, assessed the temporal resolution. These new metrics were tested on two fluoroscopy systems, a C-arm and a floor-mounted cardiology, for multiple parameters: phantom thicknesses from 5 to 20 cm, frame rates from 3 to 30 fps, spatial and temporal image processing of different weights. Main results. The frame NEQ correctly described the image quality for different scatter conditions, temporal resolutions and image processing techniques. The frame system DQE varied between 0.38 and 0.65 within the different beam and scatter conditions, and correctly mitigated the influence of spatial and temporal image processing. Significance. This study introduces and validates an unbiased formulation of in-plane NEQ and system DQE to assess the spatiotemporal image quality of fluoroscopy systems.

Abstract 12414: 3D Fusion of MRI Mechanical Activation, Cardioinsight Electrical Activation, and Fluoroscopic Lead Location for CRT

Introduction: 3D image integration can help achieve personalized medicine for patients undergoing device therapy for heart failure, such as cardiac resynchronization therapy (CRT). Hypothesis: Electrical mapping data and mechanical activation from cardiac magnetic resonance (CMR) integrated with live fluoroscopic data will provide complementary information to optimize CRT procedures. Methods: Ten patients underwent cardiac CT and electrical mapping with the CardioInsight 252-electrode vest (Medtronic) during CRT implantation using a 3D-capable fluoroscopy system (Artis zeego, Siemens) and a 3D image integration software prototype (Guide-CRT, Siemens). A myocardial mechanical activation map based on strain from CMR Displacement Encoding with Stimulated Echoes (DENSE) and an electrical activation map from CardioInsight were fused with fluoroscopic images using Guide-CRT. Results: In a representative patient with LBBB and QRS duration 140 ms, integrated 3D maps of electrical and mechanical activation with the fluoroscopic lead location are shown for right/left anterior oblique (RAO/LAO) and anterior-posterior (AP) views (Figure). While the area of late mechanical activation is centered at about 3 o’clock on the mitral annulus, a slightly more anterolateral and smaller focus of late electrical activation is noted on the CardioInsight maps (Figure). Furthermore, more basal activation data is possible with the electrical maps, as strain imaging typically starts below the mitral valve. While a middle LV electrode (LV2-4) was chosen for CRT pacing based on the CMR map, the more proximal and anterolateral LV electrode could have been chosen based on the electrical map. Conclusions: Multimodality mapping and 3D fusion of mechanical activation, electrical activation, and lead position provide important information regarding electromechanical coupling and the choice of the optimal pacing location.

Bronchoscopic diagnosis of peripheral lung lesions.

Over the last decades, in addition to the traditional fluoroscopy, various and innovative guidance systems have been adopted in clinical practice for transbronchial approach to peripheral pulmonary lesions (PPLs). The aim of this article is to summarize the most recent data on available guidance systems and sampling tools, evaluating also advantages and limitations of each technique. Although several studies have been published over the last years, large randomized studies comparing the different techniques are scanty. Fluoroscopy is the traditional and still most widely utilized guidance system. New guidance systems (electromagnetic navigation bronchoscopy, ultrasound miniprobe, cone beam computed tomography) seems to provide a better sensitivity, especially for small lesions not visualized by fluoroscopy. Among the sampling instruments, there is a good evidence that flexible transbronchial needle provides the better diagnostic yield and that sensitivity may increase if more than one sampling instrument is used. Even if great progress has been done since the first articles on the transbronchial approach to PPLs, better scientific evidence and more reliable randomized trials are needed to guide interventional pulmonologists in choosing the best technique according to different clinical scenarios and source availability.