Impact of biplane versus single-plane imaging on radiation dose, contrast load and procedural time in coronary angioplasty

Dynamic coronary roadmap in percutaneous coronary intervention: a systematic review and meta-analysis

BACKGROUND

Contrast-induced acute kidney injury (CI-AKI) is one of the complications of percutaneous coronary intervention (PCI) with high financial burden and poor outcomes. Dynamic coronary roadmap (DCR) is one of the augmentation tools that can provide a dynamic clear coronary mapping with the potential to reduce contrast use and CI-AKI incidence. Herein, we aim to systematically investigate the studies that have assessed the effect of DCR on PCI outcomes.

METHODS

Four online databases including PubMed, Scopus, Embase, and the Web of Science were systematically searched for relevant studies. Studies that compared the DCR group with the non-DCR group were included while the outcomes were AKI incidence, contrast volume, fluoroscopy time, dose area product, air kerma, intravascular ultrasonography (IVUS) use, and procedural success. Random-effect meta-analysis was conducted to calculate the standardized mean difference (SMD) or odds ratio (OR) and 95% confidence interval (CI) for comparison of DCR and non-DCR groups.

RESULTS

A total of six studies were included in the final analysis comprised of 447 patients in the DCR group and 527 in the non-DCR group. The mean age was 68.7 ± 10.6 years while 78.9% of the DCR group and 75.6% of the non-DCR group were males. There was no difference between the groups in terms of the rates of hypertension, diabetes, hyperlipidemia, prior myocardial infarction (MI), prior coronary artery bypass grafting (CABG), and atrial fibrillation. Meta-analysis revealed that patients in the DCR group had a significantly lower rate of AKI (OR 0.50, 95% CI 0.27 to 0.93, p-value = 0.028), and contrast volume used (SMD -1.16, 95% CI -2.15 to -0.18, p-value = 0.021). However, there was no difference in fluoroscopy time (SMD -0.64, 95% CI -1.43 to 0.16, p-value = 0.116), air kerma (SMD -1.81, 95% CI -4.61 to 0.99, p-value = 0.206), IVUS use (OR 1.21, 95% CI 0.85 to 1.73, p-value = 0.285), and procedural success (OR 1.05, 95% CI 1.15 to 7.26, p-value = 0.957).

CONCLUSION

These findings show that DCR use is associated with a lower rate of AKI and lower contrast use, compared to conventional PCI. This is of particular importance since many patients undergoing PCI have limited renal function and hence will benefit from the use of DCR. Further studies are needed to confirm these findings and to pave the way for the routine use of DCR in clinical settings.

Advancements in total knee arthroplasty kinematics: 3D implant computer aided design model creation through X-ray or fluoroscopic images

BACKGROUND

3D-to-2D fluoroscopic registration is a popular and important step for analyzing total-knee-arthroplasty weight-bearing kinematics. Unfortunately, in vivo analyses using these techniques cannot be completed if the associated computer-aided design implant models are not available. This study introduces a novel method that enables the accessible computation of knee replacement patients' kinematics from fluoroscopy, achieved through the reconstruction of 3-dimensional knee component models using a limited set of 2-dimensional X-ray or fluoroscopic images.

METHODS

The proposed non-rigid morphing algorithm, based on the coherent point drift algorithm, scales and transforms the shape of the template model to fit with the silhouette of the corresponding fluoroscopic images without changing the structure of the knee implant. While a greater number of fluoroscopic images can lead to higher accuracy, our study utilizes only 4 images.

FINDINGS

The morphed models show excellent results in comparison with known models with a 0.52 mm average root-mean-square error and a 2.82 mm largest source error for 17 tested knee models of various implant types. The proposed algorithm also enables direct output of patient kinematics using fluoroscopy, with an average error of only 0.54 ± 0.42 mm for femorotibial contact and 0.86 ± 0.34 degrees for axial rotation.

INTERPRETATION

A novel methodology was introduced to overcome common 3-dimentional to 2-dimensional registration limitations by recreating entire families of 3 dimensional models from a limited number of fluoroscopic images for both cruciate-retaining and posterior-stabilized knee replacement implants. Our algorithm has demonstrated high levels of accuracy with multiple potential extended applications.

Diagnostic Reference Levels in Interventional Pediatric Cardiology: Two-Year Experience in a Tertiary Referral Hospital in Latin America

The goal of the present study was to propose the first local diagnostic reference levels (DRLs) for interventional pediatric cardiology procedures in a large hospital in Colombia. The data collection period was from April 2020 to July 2022. The local DRLs were calculated as the 3rd quartile of patient-dose distributions for the kerma-area product (Pka) values. The sample of collected clinical procedures (255) was divided into diagnostic and therapeutic procedures and grouped into five weight and five age bands. The Pka differences found between diagnostic and therapeutic procedures were statistically significant in all weight and age bands, except for the 1-5-year age group. The local DRLs for weight bands were 3.82 Gy·cm2 (<5 kg), 7.39 Gy·cm2 (5-<15 kg), 19.72 Gy·cm2 (15-<30 kg), 28.99 Gy·cm2 (30-<50 kg), and 81.71 Gy·cm2 (50-<80 kg), respectively. For age bands, the DRLs were 3.97 Gy·cm2 (<1 y), 9.94 Gy·cm2 (1-<5 y), 20.82 Gy·cm2 (5-<10 y), 58.00 Gy·cm2 (10-<16 y), and 31.56 Gy·cm2 (<16 y), respectively. In conclusion, when comparing our results with other existing DRL values, we found that they are similar to other centers and thus there is scope to continue optimizing the radiation dose values. This will contribute to establishing national DRLs for Colombia in the near future.

Contrast Media Volume Control and Acute Kidney Injury in Acute Coronary Syndrome: Rationale and Design of the REMEDIAL IV Trial

Background

Although the pathogenesis of acute kidney injury (AKI) in patients with acute coronary syndrome (ACS) undergoing invasive treatment is multifactorial, the role of iodinated contrast media (CM) has been well established. The DyeVert system (Osprey Medical) is designed to reduce the CM volume during invasive coronary procedures while maintaining fluoroscopic image quality.

Objective

The aim of the Renal Insufficiency Following Contrast Media Administration Trial IV (REMEDIAL IV) is to test whether the use of the DyeVert system is effective in reducing contrast-associated acute kidney injury (CA-AKI) rate in patients with ACS undergoing urgent invasive procedures.

Trial Design

Patients with ACS treated by urgent invasive approach will be enrolled. Participants will be randomly assigned into one of the following groups: (1) DyeVert group and (2) control group. In participants enrolled in the DyeVert group, CM injection will be handled by the DyeVert system. On the contrary, in the control group, CM injection will be performed by a conventional manual or automatic injection syringe. In all cases, iobitridol (a low-osmolar, nonionic CM) will be administered. Participants will receive intravenous 0.9% sodium chloride as soon as moved to the catheterization laboratory. The primary end points are CM volume administration and CA-AKI rate (ie, an increase in serum creatinine concentration of ≥0.3 mg/dL within 48 hours after CM exposure). A sample size of at least 522 randomized participants (261 in each group) is needed to demonstrate an 8.5% difference in the CA-AKI rate between the groups (that is, from 19% in the control group to 10.5% in the DyeVert group), with a 2-sided 95% confidence interval and 80% power (P < .05).

Management of Patients With Kidney Disease in Need of Cardiovascular Catheterization: A Scientific Workshop Cosponsored by the National Kidney Foundation and the Society for Cardiovascular Angiography and Interventions

Patients with chronic kidney disease (CKD) are at an increased risk of developing cardiovascular disease (CVD), whereas those with established CVD are at risk of incident or progressive CKD. Compared with individuals with normal or near normal kidney function, there are fewer data to guide the management of patients with CVD and CKD. As a joint effort between the National Kidney Foundation and the Society for Cardiovascular Angiography and Interventions, a workshop and subsequent review of the published literature was held. The present document summarizes the best practice recommendations of the working group and highlights areas for further investigation.

An Electromagnetically Controllable Microrobotic Interventional System for Targeted, Real-Time Cardiovascular Intervention

Robotic magnetic manipulation systems offer a wide range of potential benefits in medical fields, such as precise and selective manipulation of magnetically responsive instruments in difficult-to-reach vessels and tissues. However, more preclinical/clinical studies are necessary before robotic magnetic interventional systems can be widely adopted. In this study, a clinically translatable, electromagnetically controllable microrobotic interventional system (ECMIS) that assists a physician in remotely manipulating and controlling microdiameter guidewires in real time, is reported. The ECMIS comprises a microrobotic guidewire capable of active magnetic steering under low-strength magnetic fields, a human-scale electromagnetic actuation (EMA) system, a biplane X-ray imaging system, and a remote guidewire/catheter advancer unit. The proposed ECMIS demonstrates targeted real-time cardiovascular interventions in vascular phantoms through precise and rapid control of the microrobotic guidewire under EMA. Further, the potential clinical effectiveness of the ECMIS for real-time cardiovascular interventions is investigated through preclinical studies in coronary, iliac, and renal arteries of swine models in vivo, where the magnetic steering of the microrobotic guidewire and control of other ECMIS modules are teleoperated by operators in a separate control booth with X-ray shielding. The proposed ECMIS can help medical physicians optimally manipulate interventional devices such as guidewires under minimal radiation exposure.

Determination of geometric information and radiation field overlaps on the skin in percutaneous coronary interventions with computer-aided design-based X-ray beam modeling

PURPOSE

This study aimed to develop a method for the determination of the source-to-surface distance (SSD), the X-ray beam area in a plane perpendicular to the beam axis at the entrance skin surface (Ap ), and the X-ray beam area on the actual skin surface (As ) during percutaneous coronary intervention (PCI).

MATERIALS AND METHODS

Male and female anthropomorphic phantoms were scanned on a computed tomography scanner, and the data were transferred to a commercially available computer-aided design (CAD) software. A cardiovascular angiography system with a 200 × 200 mm flat-panel detector with a field-of-view of 175 × 175 mm was modeled with the CAD software. Both phantoms were independently placed on 40 mm thick pads, and the examination tabletop at the patient entrance reference point. Upon panning, the heart center was aligned to the central beam axis. The SSD, Ap , and As were determined with the measurement tool and Boolean intersection operations at 10 gantry angulations.

RESULTS

The means and standard deviations of the SSD, Ap , and As for the male and female phantoms were 573 ± 15 and 580 ± 15 mm, 8799 ± 1009 and 9661 ± 1152 mm2 , 10495 ± 602 and 11913 ± 600 mm2 , respectively. The number of As overlaps for the male and female phantoms were 15/45 and 21/45 view combinations, respectively.

CONCLUSIONS

CAD-based X-ray beam modeling is useful for the determination of the SSD, Ap , and As . Furthermore, the knowledge of the As distribution helps to reduce the As overlap in PCI.

Agreement between single plane and biplane derived angiographic fractional flow reserve in patients with intermediate coronary artery stenosis

Fractional flow reserve (FFR) is often used to evaluate the physiological severity of intermediate coronary stenoses, but less-invasive assessment methods are desirable. We evaluated the feasibility of angiographic FFR (angioFFR) calculated from two projections acquired simultaneously by a biplane C-arm system and angioFFR calculated from two projections acquired independently by one plane of the same biplane C-arm system. AngioFFR was validated against FFR in terms of detection of hemodynamically relevant coronary artery stenoses. Twenty-two Patients who underwent angiography and FFR for coronary artery disease were included. We used a non-commercial prototype to calculate biplane angioFFR for 22 vessels (19 LAD, 1 LCx, 2 RCA) and single plane angioFFR for 17 of the same 22 vessels. FFR < 0.8 was measured in 8 vessels. The Pearson correlation coefficients with FFR were 0.55 for single plane angioFFR and 0.61 for biplane angioFFR and the diagnostic accuracies were 88% (95% CI 73-100%) for single plane angioFFR and 86% (95% CI 72-100%) for biplane angioFFR. Bland-Altman plots revealed that compared with FFR, the limits of agreement for single plane angioFFR were  - 0.07 to 0.19 (mean difference 0.06, p = 0.002) and the limits of agreement for biplane FFR were  - 0.09 to 0.15 (mean difference 0.03, p = 0.03). In conclusion, angioFFR calculated from single or biplane acquisitions by a biplane C-arm is feasible and may evolve to a tool for less invasive imaging-based assessment of myocardial ischemia.

Impact of Patient BMI on Patient and Operator Radiation Dose During Percutaneous Coronary Intervention

AIMS

This study sought to investigate patient and operator radiation dose in patients undergoing percutaneous coronary intervention (PCI) and the impact of body mass index (BMI) on patient and operator dose.

METHODS

In patients undergoing PCI, radiation dose parameters, baseline characteristics and procedural data were collected in a tertiary centre for 3.5 years. Operators wore real time dosimeters. Patients were grouped by BMI. Dose area product (DAP) and operator radiation dose were compared across patient BMI categories. Multivariable analysis was performed to investigate the impact of patient BMI and other procedural variables on patient and operator dose.

RESULTS

2,043 patients underwent 2,197 PCI procedures. Each five-unit increase in BMI increased patient dose (expressed as DAP) by an average 31% (95% CI: 29-33%) and operator dose by 27% (95% CI: 20-33%). Patient dose was 2.3 times higher and operator dose was 2.4 times higher in patients with a BMI>40 than for normal BMI patients. Multivariable analysis indicated that there were many procedural factors that were predictors for increasing operator dose and patient dose but that patient BMI was a major contributor for both operator dose and patient dose.

CONCLUSION

Increasing BMI increases the DAP and operator dose for PCI procedures and BMI is demonstrated to be a major factor that contributes to both patient and operator radiation dose.

Shifting Spine Interventional Pain Injections From the Hospital to a Clinic Setting: Increased Efficiency and Decreased Health System Costs

OBJECTIVE

Spine interventional pain injections have dramatically increased in volume in the past three decades. High referral volumes at our institution necessitated using both a hospital-based interventional suite and a clinic-based suite scheduled on a first-come, first-served basis. We sought to determine whether the clinic-based suite provided benefits in efficiency and health system cost in comparison with the hospital suite without compromising quality of care.

METHODS

To investigate differences between outpatient procedures performed in hospital-based procedure rooms (HBPRs) and clinic-based procedure rooms (CBPRs), we reviewed all consecutive outpatient spine interventional pain procedures performed by the interventional neuroradiology service over a 12-month period. We analyzed procedure complexity, fluoroscopic times, procedural times, patient wait times, and health system costs for each case, as well as any complications.

RESULTS

Our analysis demonstrated similar procedural complexity between sites with decreased average fluoroscopic time (112 seconds versus 163 seconds, P = .002), procedural time (17 min versus 28 min, P < .001), and wait time (20 min versus 38 min, P < .001) in the CBPR versus the HBPR. In cases without trainee involvement, procedural and wait times were decreased (P < .001, P = .008) with no difference in fluoroscopy time (P = .18). There were no complications at either site. The analysis of cost to the health system demonstrated that procedures in the HBPR cost >14 times the amount to perform than in the CBPR.

DISCUSSION

Performing spine interventional pain procedures in a CBPR adds value by decreasing procedural, fluoroscopic, wait times, and health system cost compared with an HBPR without compromising safety.

A randomised comparison of monoplane versus biplane fluoroscopy in patients undergoing percutaneous coronary intervention: the RAMBO trial

AIMS

Interventional cardiologists are exposed to substantial occupational ionising radiation. This study sought to investigate differences in radiation exposure in biplane versus monoplane coronary angiography and percutaneous coronary interventions (PCI).

METHODS AND RESULTS

RAMBO (RAdiation exposure in Monoplane versus Biplane cOronary angiography and interventions) was a prospective, randomised, two-arm, single-centre, open-label trial, enrolling a total of 430 patients undergoing coronary angiography. Patients were randomly assigned to biplane or monoplane imaging. The primary efficacy measure, the operator radiation dose at the level of the left arm as measured by a wearable electronic dosimeter, was significantly higher in the biplane as compared to the monoplane group (4 [1-13] µSv vs 2 [0-6.8] µSv, p<0.001). The dose area product was 11,955 (7,095-18,246) mGy*cm2 and 8,349 (5,851-14,159) mGy*cm2 in the biplane and the monoplane groups, respectively (p<0.001). While fluoroscopy time did not differ between the groups (p=0.89), the amount of contrast medium was lower with biplane as compared with monoplane imaging (p<0.001).

CONCLUSIONS

Biplane imaging for coronary angiography and PCI is related to an increased radiation exposure for the interventional cardiologist as compared with monoplane imaging. Monoplane imaging should be considered for advanced radioprotection in cardiac catheterisation, with biplane imaging used for selected cases only.

Safety and Effectiveness of Neuro-thrombectomy on Single compared to Biplane Angiography Systems

An increasing number of centers not necessarily equipped with biplane (BP) angiosuites are performing mechanical thrombectomy (MT) in acute ischemic stroke patients. We assessed whether MT performed on single-plane (SP) is equivalent in terms of safety, effectiveness, radiation and contrast agent exposure. Consecutive patients treated by MT in four high volume centers between January 2014 and May 2017 were included. Demographic and MT characteristics were assessed and compared between SP and BP. Of 906 patients treated by MT, 576 (64%) were handled on a BP system. After multivariate analysis, contrast load and fluoroscopy duration were significantly lower in the BP group [100vs200mL, relative effect 0.85 (CI: 0.79-0.92), p = 0.0002; 22 vs 27 min, relative effect 0.84 (CI: 0.76-0.93), p = 0.0008, respectively]. There was no difference in recanalization (modified Thrombolysis-In-Cerebral-Infarction 2b-3), good clinical outcome (modified Rankin Scale 0-2), complications rates, procedure duration or radiation exposure. A three-vessel diagnostic angiogram performed prior to MT led to a significant increase in procedure duration (15% increase, p = 0.05), radiation exposure (33% increase, p < 0.0001) and contrast load (125% increase, p < 0.0001). Mechanical neuro-thrombectomy seems equally safe and effective on a single or biplane angiography system despite increased contrast load and fluoroscopy duration on the former.

Biomechanical Stress Profiling of Coronary Atherosclerosis: Identifying a Multifactorial Metric to Evaluate Plaque Rupture Risk

OBJECTIVES

The purpose of this study was to derive a biomechanical stress metric that was based on the multifactorial assessment of coronary plaque morphology, likely related to the propensity of plaque rupture in patients.

BACKGROUND

Plaque rupture, the most frequent cause of coronary thrombosis, occurs at locations of elevated tensile stress in necrotic core fibroatheromas (NCFAs). Finite element modeling (FEM), typically used to calculate tensile stress, is computationally intensive and impractical as a clinical tool for locating rupture-prone plaques. This study derived a multifactorial stress equation (MSE) that accurately computes peak stress in NCFAs by combining the influence of several morphological parameters.

METHODS

Intravascular ultrasound and optical frequency domain imaging were conducted in 30 patients, and plaque morphological parameters were defined in 61 NCFAs. Multivariate regression analysis was applied to derive the MSE and compute a peak stress metric (PSM) that was based on the analysis of plaque morphological parameters. The accuracy of the MSE was determined by comparing PSM with FEM-derived peak stress values. The ability of the PSM in locating plaque rupture sites was tested in 3 additional patients.

RESULTS

The following parameters were found to be independently associated with peak stress: fibrous cap thickness (p < 0.0001), necrotic core angle (p = 0.024), necrotic core thickness (p < 0.0001), lumen area (p < 0.0001), necrotic core including calcium areas (p = 0.017), and plaque area (p = 0.003). The PSM showed excellent correlation (R = 0.85; p < 0.0001) with FEM-derived peak stress, thus confirming the accuracy of the MSE. In only 56% (n = 34) of plaques, the thinnest fibrous cap thickness was a determining parameter in identifying the cross section with highest PSM. In coronary segments with plaque ruptures, the MSE precisely located the rupture site.

CONCLUSIONS

The MSE shows potential to calculate the PSM in coronary lesions rapidly. However, further studies are warranted to investigate the use of biomechanical stress profiling for the prognostic evaluation of patients with atherosclerosis.

Neurointerventionalist and Patient Radiation Doses in Endovascular Treatment of Acute Ischemic Stroke

PURPOSE

To evaluate the patient and the neurointerventionalist radiation dose levels during endovascular treatment of acute ischemic stroke, and to analyze factors affecting doses.

MATERIALS AND METHODS

From October 2017 to January 2019, we prospectively collected patient radiation data and neurointerventionalist data from real-time dosimetry from all consecutive thrombectomies. Multivariate analysis was performed to analyze patient total dose area product (DAP) and neurointerventionalist dose variability in terms of clinical characteristics and the technical parameters of thrombectomies. Local dose reference levels (RL) were derived as the 75th percentile of the patient dose distributions.

RESULTS

A total of 179 patients were treated during the study period and included in this study. Local dose RL for thrombectomy was derived for total DAP to 34 Gy cm², cumulative air kerma of 242 mGy and fluoroscopy time of 12 min. The mean neurointerventionalist dose for thrombectomy was 7.7 ± 7.4 µSv. Height (P = 0.018), weight (P = 0.004), body mass index (P = 0.015), puncture to recanalisation (P < 0.001), fluoro time (P < 0.001), number of passes (P < 0.001), thrombolysis in cerebral infarction 2b/3 recanalisation (P = 0.034) and aspiration thrombectomy (P < 0.001) were independent factors affecting patient total DAP, whereas baseline National Institutes of Health Stroke Scale (P = 0.043), puncture to recanalisation (P = 0.003), fluoroscopy time (P = 0.009) and number of passes (P = 0.009) were factors affecting the neurointerventionalist dose.

CONCLUSION

New reference patient doses lower than those in previously published studies were defined. However, the operator's doses were higher than those in the only available study reporting on operator's dose during cerebral interventions.

Effect of a Contrast Modulation System on Contrast Media Use and the Rate of Acute Kidney Injury After Coronary Angiography

OBJECTIVES

The aim of the AVERT (AVERT Clinical Trial for Contrast Media Volume Reduction and Incidence of CIN) trial was to test the efficacy of the AVERT system to reduce the contrast media volume (CMV) used during coronary angiographic procedures without impairing image quality and to prevent contrast-induced acute kidney injury (CI-AKI) in patients at risk for CI-AKI.

BACKGROUND

CI-AKI is a common complication of percutaneous coronary procedures, associated with increased morbidity and mortality. The AVERT system alters the coronary injection pressure profile by diverting contrast away from the patient during coronary injection.

METHODS

The AVERT trial was a prospective, multicenter, 1:1 randomized clinical trial in 578 subjects with either baseline estimated glomerular filtration rate 20 to 30 ml/min/1.73 m² or estimated glomerular filtration rate 30 to 60 ml/min/1.73 m² and at least 2 additional risk factors for CI-AKI. Patients undergoing coronary angiography with planned or possible percutaneous coronary intervention (PCI) were randomized to hydration plus the AVERT system (n = 292) or hydration only (n = 286). The primary effectiveness endpoints were: 1) the total CMV used; and 2) the incidence of CI-AKI, defined as a ≥0.3 mg/dl increase in serum creatinine within 5 days post-procedure.

RESULTS

Patient demographics were well balanced between the groups, with mean baseline serum creatinine of 1.6 ± 0.4 mg/dl and 64.9% patients with diabetes mellitus. PCI was performed in 42.2% of procedures, with coronary angiography in the remainder. Use of AVERT resulted in a 15.5% relative reduction in CMV overall (85.6 ± 50.5 ml vs. 101.3 ± 71.1 ml; p = 0.02) and a 22.8% relative reduction in CMV among PCI patients (114 ± 55 ml vs. 147 ± 81 ml; p = 0.001). The maximum relative reduction in CMV was 46% (124 ± 48 ml vs. 232 ± 97 ml; p = 0.01) when ≥3 lesions were treated. There were no differences in the rates of CI-AKI (27.0% vs. 26.6%; p = 0.70) between the study groups.

CONCLUSIONS

Use of the AVERT system was feasible and safe, with acceptable image quality during coronary angiography and PCI. AVERT significantly reduced CMV, with the extent of CMV reduction correlating with procedural complexity. No significant differences in CI-AKI were observed with AVERT in this trial. (AVERT Clinical Trial for Contrast Media Volume Reduction and Incidence of CIN [AVERT]; NCT01976299).

Bi-plane and single plane angiography: a study to compare contrast usage and radiation doses for adult cardiac patients in diagnostic studies

OBJECTIVE:

This study compares the performance of bi-plane coronary angiography against single plane angiography in terms of the volume of contrast used (ml) and the total dose-area product (DAP) (μGym²) to the patient measured directly via flat panel detectors.

METHODS:

A total of 5176 adult diagnostic cardiac angiograms from a hospital in Brisbane, Australia were retrospectively studied. Patients with aortograms, iliac or femoral artery imaging, and stenting or graft interventions were excluded. Student's t-tests were used to compare means, and confounding variables were compared using multivariate regression. This quantified the effects of bi-plane system use holding constant other factors (e.g.) body mass index (BMI), age, room, sex, number of digital acquisitions and fluoro time.

RESULTS:

Bi-plane imaging had an average difference in mean contrast use of -15.1 ml [15.5% 95% confidence interval (CI) (-13.2, -17.0) p<0.001], multivariate regression demonstrated a -27.0 ml reduction in contrast use [28% 95% CI (-29.0, -24.83) p<0.0001] when the significant effects of fluoro time, number of digital acquisitions, BMI and sex were held constant. Bi-plane imaging had an average difference in mean DAP of + 887.1 μGym² [23% 95% CI (+1110.7, +663.4) p < 0.001], whilst multivariate regression found a +628.3 Gym² increase in DAP [16% 95% CI (+467.5, +789.3) p<0.001] when the significant effects of fluoro time, number of digital acquisitions, BMI and sex were held constant.

CONCLUSION:

These results demonstrate that bi-plane imaging uses less contrast media than single-plane imaging for coronary angiography at the expense of more radiation. Bi-plane imaging may be preferable in patients with renal impairment, however single plane imaging may be preferable in those without renal impairment.

ADVANCES IN KNOWLEDGE:

This is a large cohort and statistically comprehensive study comparing bi-plane and single plane coronary angiography. Other studies 4, 5, 6, 12 have used Student's t-tests to measure the difference between means, however this provides no causative information on the differences found. This study provides a view of the causative impact of bi-plane usage on DAP and contrast use via multivariate regression modelling.

Impact of single-plane versus Bi-plane imaging on procedural time, fluorescence time, and contrast medium volume in retrograde chronic total occlusion percutaneous coronary intervention

OBJECTIVE

The aim of the study is to evaluate the impact of single-plane and bi-plane imaging on procedural time, fluorescence time, and contrast medium volume in retrograde chronic total occlusion (CTO) percutaneous coronary intervention (PCI).

METHODS

Between January 2008 and December 2015, a total of 359 patients received scheduled retrograde CTO PCI and were enrolled in the study; 119 patients underwent PCI by single-plane imaging, and another 240 patients underwent PCI by bi-plane imaging.

RESULTS

A 95.0% rate of technical success was noted in the single-plane imaging group, and a 95.8% rate of technical success was noted in the bi-plane imaging group. All patients received the CTO approach via the retrograde method, and the retrograde method success rate was 88.2% in single-plane imaging group, and 81.7% in the bi-plane imaging group. A longer procedural time (153.73 ± 53.15 vs 172.88 ± 61.30 min; P = 0.004), longer fluorescence time (71.40 ± 25.96 vs 80.95 ± 34.70 min; P = 0.008), and more contrast medium volume (342.77 ± 102.25 vs 394.58 ± 156.41 mL; P = 0.001) were noted in the bi-plane imaging group. After propensity score match, a longer procedural time, longer fluorescence time, and more contrast volume was noted in bi-plane group.

CONCLUSION

Bi-plane imaging could not decrease procedural time, fluorescence time, and contrast medium volume in retrograde CTO PCI.

Dynamic coronary roadmapping during percutaneous coronary intervention: a feasibility study

BACKGROUND

A novel software ("Dynamic Coronary Roadmap") was developed, which offers a real-time, dynamic overlay of the coronary tree on fluoroscopy. Once the roadmap has been automatically generated during angiography it can be used for navigation during percutaneous coronary interventions (PCI). As a feasibility study, we aimed to investigate the feasibility of real-time dynamic coronary roadmapping and consecutive coronary overlay during elective PCI.

METHODS AND RESULTS

We studied 936 overlay runs, created following the same amount of angiographies, which were generated during 36 PCIs. Feasibility of dynamic coronary roadmapping was analyzed using a dedicated software tool. Roadmap quality (correct dynamic imaging of the vessels without relevant artefacts or missing parts) was distinguished from overlay quality (congruence of dynamic coronary roadmapping and coronary anatomy). Additionally, we assessed procedural success and the occurrence of major cardiac and cerebrovascular events (MACCE). Roadmap quality was defined as "fit for use" in 99.5%. In 97.4% of runs overlay quality was deemed "fit for use". Overall, we observed low inter and intra observer variability (ICC R = 0.84 for roadmap quality and R = 0.75 for overlay quality). Procedural success rate was 100%. MACCE occurred in two (5.6%) patients during post-interventional in-hospital stay and were not software-related.

CONCLUSIONS

Dynamic coronary roadmapping provides in > 98% of cases sufficient roadmap quality with an anatomically correct overlay of the coronary vessels with good inter and intra observer variability. Future randomized studies are warranted to test possible advantages like procedure time reduction and less consumption of contrast medium.

An Automatic 3-D Reconstruction of Coronary Arteries by Stereopsis

Stereopsis of X-ray images can produce 3D tree of coronary arteries up to a certain accuracy level with a lower dose of radiation when compared to computer tomography (CT). In this study, a novel and complete automatic system is designed that covers preprocessing, segmentation, matching and reconstruction steps for that purpose. First, an automatic and novel pattern recognition technique is applied for extraction of the bifurcation points with their diameters recorded in a map. Then, a novel optimization algorithm is run for matching the branches efficiently which is based on that map and the epipolar geometry of stereopsis. Finally, cut branches are fixed one by one at the bifurcations for completing the 3D reconstruction. This method prevails the similar ones in the literature with this novelty since it automatically and inherently prevents the wrong overlapping of branches. Other essential problems like correct detection of the bifurcations and accurate calibration parameters and fast overlapping of matched branches are addressed at acceptable levels. The accuracy of bifurcation extraction is high at 90 % with 96 % sensitivity. Accuracy of vessel centerlines has rootmean-square (rms) error smaller than 0.57 mm for 20 different patients. For phantom model, rms error is 0.75 ± 0.8 mm in 3D localization.

A prospective case control comparison of the ZeroGravity system versus a standard lead apron as radiation protection strategy in neuroendovascular procedures

Background and purpose

We aimed to compare the performance of the ZeroGravity (ZG) system (radiation protection system composed by a suspended lead suit) against the use of standard protection (lead apron (LA), thyroid shield, lead eyeglasses, table skirts, and ceiling suspended shield) in neuroangiography procedures.

Materials and methods

Radiation exposure data were prospectively collected in consecutive neuroendovascular procedures between December 2014 and February 2015. Operator No 1 was assigned to the use of an LA (plus lead glasses, thyroid shield, and a 1 mm hanging shield at the groin) while operator No 2 utilized the ZG system. Dosimeters were used to measure peak skin dose for the head, thyroid, and left foot.

Results

The two operators performed a total of 122 procedures during the study period. The ZG operator was more commonly the primary operator compared with the LA operator (85% vs 71%; p=0.04). The mean anterior-posterior (AP), lateral, and cumulative dose area product (DAP) radiation exposure as well as the mean fluoroscopy time were not statistically different between the operators’ cases. The peak skin dose to the head of the operator with LA was 2.1 times higher (3380 vs 1600 μSv), while the thyroid was 13.9 (4460 vs 320 μSv), the mediastinum infinitely (520 vs 0 μSv), and the foot 3.3 times higher (4870 vs 1470 μSv) compared with the ZG operator, leading to an overall accumulated dose 4 times higher. The ratio of cumulative operator received dose/total cumulative DAP was 2.5 higher on the LA operator.

Conclusions

The ZG radiation protection system leads to substantially lower radiation exposure to the operator in neurointerventional procedures. However, substantial exposure may still occur at the level of the lens and thyroid to justify additional protection.

Optimisation of coronary angiography exposures requires a multifactorial approach and careful procedural definition

OBJECTIVE

This study investigates the factors associated with higher doses for both single-plane and biplane procedures and establishes centre-specific 75th percentile levels.

METHODS

602 patients undergoing coronary angiography in a large hospital at Sydney were recruited to the study, and causal agents for high radiation doses were investigated: gender, procedural complexity, severity of coronary artery disease, presence of coronary bypass grafts, entry approach (radial or femoral), level of operator experience; and a single-plane or a biplane imaging system was employed.

RESULTS

The 75th percentile levels were calculated. The results demonstrated that, for both systems, higher exposures were associated with patients who were male (p<0.001), had coronary vessel disease (p<0.001) and had a history of coronary bypass grafts (p<0.001). In addition, for biplane systems, procedural complexity (p<0.001), types of entry approach (p<0.001) and levels of operator experience (p<0.001) significantly impacted upon the dose. Biplane examinations recorded higher doses than single-plane procedures (p<0.001) and the inclusion of left-sided ventriculography contributed to the overall dose by up to 10%.

CONCLUSION

The 75th percentile levels in this study represent the tentative reference levels and are 48.9, 44.2 and 56 Gy cm(2) for all exposures, single-plane- and biplane-specific exposures, respectively, and compare favourably with the diagnostic reference level values established elsewhere internationally, with only the UK and Irish data being lower.

ADVANCES IN KNOWLEDGE

Specific agents have been identified for dose-reducing strategies and the importance of operator training is highlighted. The assumption that biplane procedures may reduce the patient dose should be treated with caution.

Is hair loss a reality in neuro-interventional radiology?

Reports in the literature of radiation-induced hair loss are becoming increasingly common. This work describes a retrospective dose study of patients (n = 958) undergoing diagnostic (primarily cerebral angiograms) and therapeutic (primarily cerebral embolisation) procedures in a neuro-interventional suite. A comparison of patient doses as dose area product (DAP) readings from a single-plane image intensifier system (mean DAP value of 8772 cGy cm²) were compared with patient doses from a flat panel biplane system (mean DAP value of 7855 cGy cm²). Over 80 % of patients requiring neuro-interventional procedures were found to undergo two procedures or more. An estimated 7 % of therapeutic procedures were found to reach the International Commission on Radiological Protection threshold for temporary epilation.