Overall Impact of the COVID-19 Pandemic on Interventional Radiology Services: A Canadian Perspective

PURPOSE

The aim of this national survey was to assess the overall impact of the coronavirus disease 2019 (COVID-19) pandemic on the provision of interventional radiology (IR) services in Canada.

METHODS

An anonymous electronic survey was distributed via national and regional radiology societies, exploring (1) center information and staffing, (2) acute and on-call IR services, (3) elective IR services, (4) IR clinics, (5) multidisciplinary rounds, (6) IR training, (7) personal protection equipment (PPE), and departmental logistics.

RESULTS

Individual responses were received from 142 interventional radiologists across Canada (estimated 70% response rate). Nearly half of the participants (49.3%) reported an overall decrease in demand for acute IR services; on-call services were maintained at centers that routinely provide these services (99%). The majority of respondents (73.2%) were performing inpatient IR procedures at the bedside where possible. Most participants (88%) reported an overall decrease in elective IR services. Interventional radiology clinics and multidisciplinary rounds were predominately transitioned to virtual platforms. The vast majority of participants (93.7%) reported their center had disseminated an IR specific PPE policy; 73% reported a decrease in case volume for trainees by at least 25% and a proportion of trainees will either have a delay in starting their careers as IR attendings (24%) or fellowship training (35%).

CONCLUSION

The COVID-19 pandemic has had a profound impact on IR services in Canada, particularly for elective cases. Many centers have utilized virtual platforms to provide multidisciplinary meetings, IR clinics, and training. Guidelines should be followed to ensure patient and staff safety while resuming IR services.

Multicentre prospective observational study protocol for radiation exposure from gastrointestinal fluoroscopic procedures (REX-GI study)

INTRODUCTION

Recently, the use of various endoscopic procedures under X-ray fluoroscopic guidance, such as endoscopic retrograde cholangiopancreatography (ERCP), interventional endoscopic ultrasonography (EUS), enteral endoscopy and stenting, has been rapidly increasing because of the minimally invasive nature of these procedures compared with that of surgical intervention. With the spread of CT and fluoroscopic interventions, including endoscopic procedures under X-ray guidance, high levels of radiation exposure (RE) from medical imaging have led to major concerns throughout society. However, information about RE related to these image-guided procedures in gastrointestinal endoscopy is scarce, and the RE reference levels have not been established. The aim of this study is to prospectively collect the actual RE dose and to help establish diagnostic reference levels (DRLs) in the field of gastroenterology in Japan.

METHODS AND ANALYSIS

This is a multicentre, prospective observational study that is being conducted to collect the actual RE from treatments and diagnostic procedures, including ERCP, interventional EUS, balloon-assisted enteroscopy, enteral metallic stent placement and enteral tube placement. We will measure the total fluoroscopy time (min), the total dose-area product (Gycm2) and air-kerma (mGy) of those procedures. Because we are collecting the actual RE data and identifying the influential factors through a prospective, nationwide design, this study will provide guidance regarding the DRLs of ERCP, interventional EUS, balloon-assisted enteroscopy, enteral metallic stent placement and enteral tube placement.

ETHICS AND DISSEMINATION

Approval was obtained from the Institutional Review Board of Toyonaka Municipal Hospital (25 April 2019). The need for informed consent will be waived via the opt-out method of each hospital website.

TRIAL REGISTRATION NUMBER

The UMIN Clinical Trials Registry, UMIN000036525.

IMPACT OF THE TABLE HEIGHT AND THE OPERATOR'S HEIGHT ON THE LEVEL OF RADIATION DELIVERED TO INTERVENTIONAL CARDIOLOGISTS

Interventional cardiologists count among the health professionals that are most exposed to ionising radiation. To minimise exposure, it is recommended that the patient be placed at the maximum distance possible from the X-ray source, but this recommendation has not been clinically validated. We aimed to investigate the impact of the average table height on the level of radiation delivered to cardiologists performing coronary interventions. The population for analysis included all invasive coronary procedures performed in our centre from March to June 2017. The primary endpoint was operator radiation exposure, as assessed using personal electronic dosimeters located on the operator's left arm. In total, 225 invasive coronary procedures were analysed. When the average table height was 1126 mm or more, the operators received a radiation dose that was, on average, 53% lower than when the table was lower than 1126 mm. This reduction remained significant by multivariate analysis adjusted for the operator.

Patient radiation dose in percutaneous biliary interventions: recommendations for DRLs on the basis of a multicentre study

OBJECTIVE

Percutaneous biliary interventions (PBIs) can be associated with a high patient radiation dose, which can be reduced when national diagnostic reference levels (DRLs) are kept in mind. The aim of this multicentre study was to investigate patient radiation exposure in different percutaneous biliary interventions, in order to recommend national DRLs.

METHODS

A questionnaire asking for the dose area product (DAP) and the fluoroscopy time (FT) in different PBIs with ultrasound- or fluoroscopy-guided bile duct punctures was sent to 200 advanced care hospitals. Recommended national DRLs are set at the 75th percentile of all DAPs.

RESULTS

Twenty-three facilities (9 interventional radiology depts. and 14 gastroenterology depts.) returned the questionnaire (12%). Five hundred sixty-five PBIs with 19 different interventions were included in the analysis. DAPs (range 4-21,510 cGy·cm2) and FTs (range 0.07-180.33 min) varied substantially depending on the centre and type of PBI. The DAPs of initial PBIs were significantly (p < 0.0001) higher (median 2162 cGy·cm2) than those of follow-up PBIs (median 464 cGy·cm2). There was no significant difference between initial PBIs with ultrasound-guided bile duct puncture (2162 cGy·cm2) and initial PBIs with fluoroscopy-guided bile duct puncture (2132 cGy·cm2) (p = 0.85). FT varied substantially (0.07-180.33 min).

CONCLUSIONS

DAPs and FTs in percutaneous biliary interventions showed substantial variations depending on the centre and the type of PBI. PBI with US-guided bile duct puncture did not reduce DAP, when compared to PBI with fluoroscopy-guided bile duct puncture. National DRLs of 4300 cGy·cm2 for initial PBIs and 1400 cGy·cm2 for follow-up PBIs are recommended.

KEY POINTS

• DAPs and FTs in percutaneous biliary interventions showed substantial variations depending on the centre and the type of PBI. • PBI with US-guided bile duct puncture did not reduce DAP when compared to PBI with fluoroscopy-guided bile duct puncture. • DRLs of 4300 cGy·cm2for initial PBIs (establishing a transhepatic tract) and 1400 cGy·cm2for follow-up PBIs (transhepatic tract already established) are recommended.

[Frequency and doses of diagnostic and interventional X‑ray applications : Trends between 2007 and 2014]

BACKGROUND

In Germany, approximately 95% of man-made radiation exposure of the population results from diagnostic and interventional X‑ray procedures. Thus, radiation protection of patients in this field of application is of great importance.

OBJECTIVE

Quantification and evaluation of current data on the frequency and doses of X‑ray procedures as well as temporal trends for the years 2007-2014.

MATERIAL AND METHODS

For outpatients the frequency of X‑ray procedures was estimated using reimbursement data from health insurances and for inpatients by means of hospital statistics. For the years under review, representative values for the effective dose per X‑ray application were determined mainly from data reported by X‑ray departments to the competent authorities.

RESULTS

In 2014 approximately 140 million X‑ray procedures were performed in Germany with some 40% from dental examinations. On average 1.7 procedures per inhabitant and year were almost constantly carried out between 2007 and 2014. Besides dental diagnostics, X‑ray examinations of the skeleton and thorax were performed most frequently. The number of computed tomography (CT) examinations increased by approximately 40%. The increase in magnetic resonance imaging (MRI) was even more pronounced with approximately 55% but overall CT examinations were still performed more often than MRI. The doses per X‑ray procedure were only slightly reduced, despite the various dose reduction approaches established in recent years; therefore, the mean effective dose per inhabitant increased from approximately 1.4 mSv in 2007 to 1.6 mSv in 2014, mainly due to the increasing frequency of CT examinations.

CONCLUSION

The principles of justification and optimization of radiological procedures are to be consistently applied in each individual instance, especially in the case of CT examinations.

Association Between Neurological Outcomes Related to Aneurysmal Subarachnoid Hemorrhage and Onsite Access to Neurointerventional Radiology

OBJECTIVE

An onsite access to neurointerventional radiology (NIR) may be useful for managing patients with aneurysmal subarachnoid hemorrhage (aSAH) after the aneurysm-securing procedure. We aimed to assess the association between neurological outcomes related to aSAH and onsite access to NIR service.

METHODS

This was a sequential period study of 47 patients with aSAH admitted consecutively during the pre-NIR period (January 2010 to June 2012) compared with 81 patients with aSAH admitted consecutively during the post-NIR period (January 2013 to June 2015) at an academic tertiary referral intensive care unit (ICU). The primary end point was the incidence of poor neurological outcome, defined as modified Rankin scale of ≥3 at 6 months from ictus. Secondary outcomes included incidence of symptomatic vasospasm (SV) and length of stay in ICU/hospital.

RESULTS

The primary end point was observed in 18 of 47 (38%) patients during the pre-NIR period versus 25 of 81 (31%) patients during the post-NIR period (P = 0.39). The post-NIR period did not have an independent impact on neurological outcomes (adjusted odds ratio = 0.8, 95% confidence interval 0.3-2.1; P = 0.66). Of the patients who developed SV, 10 of 47 (21%) were during the pre-NIR period versus 33 of 81 (41%) during the post-NIR period (P = 0.02). The post-NIR period and higher Fisher grade were independent predictors of SV. Patients with SV had similar outcomes, but with longer stay in ICU during the post-NIR period compared with the pre-NIR period.

CONCLUSIONS

Among patients with aSAH, the post-NIR period was associated with more frequent detection of SV, more endovascular procedures, longer hospital stay, but with no appreciable improvement in neurological outcomes either overall or in the subset of patients with SV.

STUDY REGISTRATION

Australian New Zealand Clinical Trials Registry ACTRN12616000201471.

Impact of new X-ray technology on patient dose in pacemaker and implantable cardioverter defibrillator (ICD) implantations

PURPOSE

New X-ray technology providing new image processing techniques may reduce radiation exposure. The aim of this study was to quantify this radiation exposure reduction for patients during pacemaker and implantable cardioverter defibrillator (ICD) implantation.

METHODS

In this retrospective study, 1185 consecutive patients who had undergone de novo pacemaker or ICD implantation during a 2-year period were included. All implantations in the first year were performed using the reference technology (Allura Xper), whereas in the second year, the new X-ray technology (AlluraClarity) was used. Radiation exposure, expressed as the dose area product (DAP), was compared between the two time periods to determine the radiation exposure reduction for pacemaker and ICD implantations without cardiac resynchronization therapy (CRT) and with CRT. Procedure duration and contrast volume were used as measures to compare complexity and image quality.

RESULTS

The study population consisted of 591 patients who had undergone an implantation using the reference technology, and 594 patients with the new X-ray technology. The two groups did not differ in age, gender, or body mass index. The DAP decreased with 69 % from 16.4 ± 18.5 to 5.2 ± 6.6 Gy cm2 for the non-CRT implantations (p < 0.001). The DAP decreased with 75 % from 72.1 ± 60.0 to 17.8 ± 17.4 Gy cm2 for the CRT implantations (p < 0.001). Nevertheless, procedure duration and contrast volume did not differ when using the new technology (p = 0.09 and p = 0.20, respectively).

CONCLUSIONS

Introduction of new X-ray technology resulted in a radiation exposure reduction of more than 69 % for patients during pacemaker and ICD implantation while image quality was unaffected.

Lumbar Transforaminal Epidural Steroid Injections: Incidental Extraspinal Findings on Planning Imaging

OBJECTIVE

Planning imaging performed during CT-guided procedures may occasionally contain important incidental findings. The purpose of this study was to identify and characterize by clinical relevance the extraspinal findings detected on planning imaging for CT-guided lumbar transforaminal epidural steroid injections (TFESIs).

MATERIALS AND METHODS

Four radiologists retrospectively evaluated the planning scout views and CT studies for 488 consecutive CT-guided lumbar TFESIs performed in 400 patients over a 1-year period. Incidental extraspinal findings were identified and used to characterize patients by the need for follow-up using the CT Colonography Reporting and Data System (C-RADS), a classification scheme originally developed to characterize incidental findings on CT colonography. Patients with C-RADS E4 findings have potentially important findings that should be communicated to the referring physician; patients with C-RADS E3 findings have findings that are likely unimportant, but workup may be indicated. All previously unknown C-RADS E3 and E4 findings discovered in the course of this research were reported to referring physicians for appropriate patient follow-up.

RESULTS

Ten of 400 (2.5%) patients were classified as C-RADS E4; the most common C-RADS E4 finding was vascular aneurysm or stenosis (4/400, 1.0%). Thirteen of 400 (3.3%) patients were classified as C-RADS E3; the most common C-RADS E3 finding was hepatomegaly (4/400, 1.0%). Of 22 patients with C-RADS E3 and E4 findings unknown to clinicians, the finding for only one (4.5%) was communicated to clinicians at the time of the procedure.

CONCLUSION

Clinically important incidental extraspinal findings were identified in 5.8% of patients on the planning imaging performed for CT-guided lumbar TFESIs. Communication of clinically important findings was poor (4.5%).

Changing Patterns in the Performance of Fluoroscopically Guided Interventional Procedures and Adherence to Radiation Safety Practices in a U.S. Cohort of Radiologic Technologists

OBJECTIVE

Information is limited on changes over time in the types of fluoroscopically guided interventional procedures performed and associated radiation safety practices used by radiologic technologists.

MATERIALS AND METHODS

Our study included 12,571 U.S. radiologic technologists who were certified for at least 2 years in 1926-1982 and who reported in a 2012-2013 survey that they ever performed or assisted with fluoroscopically guided interventional procedures. They completed a mailed questionnaire in 2013-2014 describing their detailed work practices for 21 fluoroscopically guided interventional procedures and associated radiation safety practices from the 1950s through 2009.

RESULTS

Overall, the proportion of technologists who reported working with therapeutic fluoroscopically guided interventional procedures, including percutaneous coronary interventions, increased over time, whereas the proportion of technologists who worked with diagnostic fluoroscopically guided interventional procedures, including diagnostic cardiovascular catheterization and neuroangiographic procedures, decreased. We also observed substantial increases in the median number of times per month that technologists worked with diagnostic cardiovascular catheterizations and percutaneous coronary interventions. In each time period, most technologists reported consistently (≥ 75% of work time) wearing radiation monitoring badges and lead aprons during fluoroscopically guided interventional procedures. However, fewer than 50% of the technologists reported consistent use of thyroid shields, lead glasses, and room shields during fluoroscopically guided interventional procedures, even in more recent time periods.

CONCLUSION

This study provides a detailed historical assessment of fluoroscopically guided interventional procedures performed and radiation safety practices used by radiologic technologists from the 1950s through 2009. Results can be used in conjunction with badge dose data to estimate organ radiation dose for studies of radiation-related health risks in radiologic technologists who have worked with fluoroscopically guided interventional procedures.

Preoperative Pelvic Tilt Analysis Reduces Fluoroscopy Time in Direct Anterior Total Hip Arthroplasty

The direct anterior approach for total hip arthroplasty (THA) requires the use of intraoperative imaging, exposing the patient and surgical team to radiation. The authors hypothesized that calculation of the preoperative pelvic tilt angle and communication of this value with the fluoroscopy technician may result in a decrease in intraoperative fluoroscopy use. The study also examined total radiation exposure during the procedure to ensure that it was within safe limits. The pelvic tilt was calculated preoperatively for 100 consecutive patients undergoing THA by the direct anterior approach. The fluoroscopy technician was blinded to the value of pelvic tilt for the first 50 cases (control group), with the angle being communicated for the following 50 cases (test group). The total duration of fluoroscopy use for each case was recorded. The values were compared for the 2 experienced technicians involved in the study. The surgeon was blinded to the duration of fluoroscopy use in all cases. Mean fluoroscopy time was 28.65 seconds in the control group and 23.61 seconds in the test group (P=.033). No significant difference in duration of fluoroscopy use was found between the 2 fluoroscopy technicians. The control group and the test group were within safe limits of radiation exposure to both the patient and the surgical team. Preoperative pelvic tilt calculation significantly decreases the amount of imaging used during THA by the direct anterior approach. Although it was a statistically significant reduction, both groups were within safe limits for both the surgical team and the patients, and thus the clinical significance is unknown. [Orthopedics.2016; 39(5):e962-e966.].

Changes in Occupational Radiation Exposures after Incorporation of a Real-time Dosimetry System in the Interventional Radiology Suite

A statistical pilot study was retrospectively performed to analyze potential changes in occupational radiation exposures to Interventional Radiology (IR) staff at Lawrence General Hospital after implementation of the i2 Active Radiation Dosimetry System (Unfors RaySafe Inc, 6045 Cochran Road Cleveland, OH 44139-3302). In this study, the monthly OSL dosimetry records obtained during the eight-month period prior to i2 implementation were normalized to the number of procedures performed during each month and statistically compared to the normalized dosimetry records obtained for the 8-mo period after i2 implementation. The resulting statistics included calculation of the mean and standard deviation of the dose equivalences per procedure and included appropriate hypothesis tests to assess for statistically valid differences between the pre and post i2 study periods. Hypothesis testing was performed on three groups of staff present during an IR procedure: The first group included all members of the IR staff, the second group consisted of the IR radiologists, and the third group consisted of the IR technician staff. After implementing the i2 active dosimetry system, participating members of the Lawrence General IR staff had a reduction in the average dose equivalence per procedure of 43.1% ± 16.7% (p = 0.04). Similarly, Lawrence General IR radiologists had a 65.8% ± 33.6% (p=0.01) reduction while the technologists had a 45.0% ± 14.4% (p=0.03) reduction.

Prophylactic Plasma Transfusion Before Interventional Radiology Procedures Is Not Associated With Reduced Bleeding Complications

OBJECTIVE

To determine the association between prophylactic plasma transfusion and periprocedural red blood cell (RBC) transfusion rates in patients with elevated international normalized ratio (INR) values undergoing interventional radiology procedures.

PATIENTS AND METHODS

In this retrospective cohort study, adult patients undergoing interventional radiology procedures with a preprocedural INR available within 30 days of the procedure during a study period of January 1, 2009, to December 31, 2013, were eligible for inclusion. Baseline characteristics, coagulation parameters, transfusion requirements, and procedural details were extracted. Univariate and multivariable propensity-matched analyses were used to assess the relationships between prophylactic plasma transfusion and the outcomes of interest, with a primary outcome assessed a priori of RBC transfusion occurring during the procedure or within the first 24 hours postprocedurally.

RESULTS

A total of 18,204 study participants met inclusion criteria for this study, and 1803 (9.9%) had an INR of 1.5 or greater before their procedure. Of these 1803 patients, 196 patients (10.9%) received prophylactic plasma transfusion with a median time of 1.9 hours (interquartile range [IQR], 1.1-3.2 hours) between plasma transfusion initiation and procedure initiation. In multivariable propensity-matched analysis, plasma administration was associated with increased periprocedural RBC transfusions (odds ratio, 2.20; 95% CI, 1.38-3.50; P<.001) and postprocedural intensive care unit admission rates (odds ratio, 2.11; 95% CI, 1.41-3.14; P<.001) as compared with those who were not transfused preprocedurally. Similar relationships were seen at higher INR thresholds for plasma transfusion.

CONCLUSION

In patients undergoing interventional radiology procedures, preprocedural plasma transfusions given in the setting of elevated INR values were associated with increased periprocedural RBC transfusions. Additional research is needed to clarify this potential association between preprocedural plasma transfusion and periprocedural RBC transfusion.

Medicare Utilization of CT Angiography from 2001 through 2014: Continued Growth by Radiologists

PURPOSE

To examine changes in utilization of computed tomography (CT) angiography nationally and changing relative specialty roles in examination interpretation.

MATERIALS AND METHODS

Service-specific claims data for region-specific CT angiography examinations were identified using Medicare Physician Supplier Procedure Summary Master Files from 2001 through 2014. Longitudinal national utilization rates were calculated using annual Medicare enrollment data for 2001-2013. Procedure volumes by specialty group and site of service were analyzed.

RESULTS

Total annual claims for CT angiography for Medicare fee for service beneficiaries increased from 64,846 to 1,709,088 (compound annual growth rate [CAGR] 29%) between 2001 and 2014. Per 1,000 beneficiaries, overall CT angiography utilization increased annually from 2.1 in 2001 to 47.6 in 2013. Overall interpretation market share increased 4% (91%-95%) for radiology. Cardiology increased from 1% in 2001 to 6% in 2007 but decreased annually to 2% in 2014. Vascular surgery market share remained < 1% throughout the study period. Growth of CT angiography in the emergency department (ED) outpaced all other sites of service, increasing from 11% to 28% (CAGR 38%). The chest was the dominant body region imaged with CT angiography, increasing from 36,984 to 914,086 (CAGR 28%).

CONCLUSIONS

Utilization of CT angiography in the Medicare population increased markedly for 2001-2014, particularly in the ED, with radiologists remaining dominant providers. The chest is the most common body region imaged with CT angiography.

EXPOSURE OF THE SWISS POPULATION BY RADIODIAGNOSTICS: 2013 REVIEW

In 2013, a nationwide investigation was conducted in Switzerland to establish the population's exposure from medical X rays. A hybrid approach was used combining the Raddose database accessible on-line by the participating practices and the Swiss medical tariffication system for hospitals. This study revealed that the average annual number of examinations is 1.2 per inhabitant, and the associated annual effective dose is 1.4 mSv. It also showed that computed tomography is the most irradiating modality and that it delivers 70 % of the total dose. The annual effective dose per inhabitant registered a 17 % increase in 5 y and is comparable with what was recently reported in neighbouring countries.

Nonvascular Interventional Procedures in an Urban General Hospital: Analysis of 2001-2010 with Comparison to the Previous Decade

RATIONALE AND OBJECTIVES

To determine trends in nonvascular image-guided procedures at an urban general hospital over a 10-year period and to compare utilization of nonvascular interventional radiology (IR) over the decade 2001-2010 to a previously reported analysis for 1991-2000.

METHODS

With institutional review board approval, a 20-year quality assurance database verified against the radiology information system was queried for procedure location (eg, pleura, liver, bowel, and abdomen) and type (eg, biopsy, catheter insertion, and transient drainage), demographics, and change over time. Yearly admissions and new hospital numbers assigned each year served to normalize for overall hospital activity.

RESULTS

A total of 50,195 IR procedures were performed in 24,309 distinct patients (male:female, 12,625:11,684; average age, 60 years), 940 procedures performed in age <20 years, and 571 procedures performed in patients aged ≥90 years. A total of 15345, 4377, and 1754 patients had one, two, or three procedures, respectively; 470 had ≥10 procedures. Twenty-seven supervising radiologists and 277 individuals participated as operators, double the previous decade. Biopsy (4.8% average yearly increase), abdominal drainage (7.3%), paracentesis (12.9%), tube manipulation (13.0%), suprapubic bladder tube insertion (21.0%), and gastrostomy (44.6%) all increased strongly (P < .001) over 120 months but not biliary drainage, nephrostomy, or chest tubes. Procedures increased faster than either admissions or new hospital numbers (P < .001). For each 1000 new hospital numbers, IR service performed 48 procedures versus 31 the previous decade (P < .0005).

CONCLUSIONS

Referrals for nonvascular IR procedures have doubled over 2 decades, outpacing growth in new hospital patients and requiring increased resource allocation.

Collective effective dose from diagnostic radiology in Ukraine

The frequencies and effective doses for the most common X-ray diagnostic examinations in Ukraine were assessed in the frame of the European Commission (EC) Study on European Population Doses from Medical Exposure (Dose Datamed 2). The average effective doses for all radiographic procedures were estimated using the ODS-60 software (Finland). The estimation of the effective doses for the chest film fluorography was carried out from the results of own representative measurements with thermoluminescent (TL) dosimetry and a standard Alderson-Rando phantom. The effective doses for fluoroscopy procedures were assessed using the Russian guidelines for estimation of effective doses. For all other X-ray examinations and procedures [computed tomography (CT), angiography and interventional procedures], typical effective dose values were taken from the EC Guidance RP154. The most frequently performed in Ukraine is chest film fluorography, with 389 examinations per 1000 population annually, reflecting in the greatest contribution to the total collective effective dose (CED) of 428 mSv per 1000 population (44 %). The total frequency and CED from all X-ray diagnostic examinations and procedures were estimated to be 1218 examinations and 1060 mSv per 1000 populations, respectively. The expected additional cancer risk from X-ray diagnostic examinations and interventional procedures is 2680 cases per year, with 1200 of them due to the contribution of chest fluorography. The main important action in radiation protection of patients in diagnostic radiology is the organisation of the monitoring of patient doses for different types of X-ray diagnostic examinations and replacement of chest film fluorography with digital X-ray systems.

Follow-up of children exposed to ionising radiation from cardiac catheterisation: the Coccinelle study

Cardiac catheterisation has become an essential tool in the diagnosis and treatment of children with a wide variety of congenital and acquired forms of cardiovascular disease. Despite the clear clinical benefit to the patient, radiation exposure from paediatric cardiac catheterisation procedures (CCPs) may be substantial. Given children's greater sensitivity to radiation and the longer life span during which radiation health effects can develop, an epidemiological cohort study, named Coccinelle or 'Ladybird' (French acronym for 'Cohorte sur le risque de cancer après cardiologie interventionnelle pédiatrique'), is carried out in France to evaluate the risks of leukaemia and solid cancers in this population. A total number of 8000 included children are expected. Individual CCP-related doses will be assessed for each child included in the cohort. For each CCP performed, dosimetric parameters (dose-area product, fluoroscopy time and total number of cine frames) are retrieved retrospectively. Organ doses, especially to the lung, the oesophagus and the thyroid, are calculated with PCXMC software. The cohort will be followed up through linkage with French paediatric cancer registries.

Patient doses in paediatric interventional cardiology: impact of 3D rotational angiography

The aim of this study was to calculate the contribution of 3D rotational angiography to radiation doses received by paediatric patients in a cardiac catheterisation laboratory. The percentage increase in the median value of air kerma-area product due to cone beam CT was 33 and 16% for diagnostic and therapeutic procedures, respectively. Results are presented separately for five age groups and ten weight groups. Several methods for reducing radiation from 3D rotational angiography are suggested and patient doses are compared with previously published values.

Influence of standing positions and beam projections on effective dose and eye lens dose of anaesthetists in interventional procedures

More and more anaesthetists are getting involved in interventional radiology procedures and so it is important to know the radiation dose and to optimise protection for anaesthetists. In this study, based on Monte Carlo simulations and field measurements, both the whole-body doses and eye lens dose of anaesthetists were studied. The results showed that the radiation exposure to anaesthetists not only depends on their workload, but also largely varies with their standing positions and beam projections during interventional procedures. The simulation results showed that the effective dose to anaesthetists may vary with their standing positions and beam projections to more than a factor of 10, and the eye lens dose may vary with the standing positions and beam projections to more than a factor of 200. In general, a close position to the bed and the left lateral (LLAT) beam projection will bring a high exposure to anaesthetists. Good correlations between the eye lens dose and the doses at the neck, chest and waist over the apron were observed from the field measurements. The results indicate that adequate arrangements of anaesthesia device or other monitoring equipment in the fluoroscopy rooms are useful measures to reduce the radiation exposure to anaesthetists, and anaesthetists should be aware that they will receive the highest doses under left lateral beam projection.

Cone-beam computed tomography imaging: therapeutic staff dose during chemoembolisation procedure

Cone-beam computed tomography (CBCT) imaging is an important requirement to perform real-time therapeutic image-guided procedures on patients. The purpose of this study is to estimate the personal-doseequivalent and annual-personal-dose from CBCT imaging during transarterial chemoembolisation (TACE). Therapeutic staff doses (therapeutic and assistant physician) were collected during 200 patient (65 ± 15 years, range: 40–86) CBCT examinations over six months. Absorbed doses were assessed using thermo-luminescent dosimeters during patient hepatic TACE therapy. We estimated personal-dose-equivalent (PDE) and annual-personal-dose (APD) from absorbed dose based oninternational atomic energy agency protocol. APD for therapeutic procedure was calculated (therapeutic physician: 5.6 mSv; assistant physician: 5.08 mSv) based on institutional work load. Regarding PDE, the hands of the staff members received a greater dose compared to other anatomical locations (therapeutic physician: 56 mSv, 72 mSv; assistant physician: 12 mSv, 14 mSv). Annual radiation doses to the eyes and hands of the staff members were lower compared to the prescribed limits by the International Commission on Radiological Protection (ICRP). PDE and APD of both therapeutic staff members were within the recommended ICRP-103 annual limit. Dose to the assistant physician waslower than the dose to the therapeutic physician during imaging. Annual radiation doses to eye-lenses and hands of both staff members were lower than prescribed limits.

Evaluation of radiation exposure of medical staff during CT-guided interventions

PURPOSE

The purpose of this prospective study was to investigate absolute radiation exposure values and factors that influence radiation exposure of interventionists during CT-guided interventions (CTGIs). To our knowledge, no data exist regarding the radiation dose to which the interventionist is exposed during these procedures.

METHODS

Absolute radiation dose values from a total of 131 CTGIs were analyzed. Radiation dose values were collected by thermoluminescent dosimeters that were positioned above the lead protection being worn, on the forehead, thyroid, chest, gonads, and right and left hand and foot. The radiation doses were analyzed with respect to the experience level of the person performing the procedure, the degree of difficulty measured on a 4-point Likert scale, the lesion size measured on a 3-point Likert scale, and the CT system used.

RESULTS

Median whole-body dose was 12 μSv. With the exception of the forehead, all whole-body radiation doses were statistically significantly lower in CTGIs performed using the modern dual-source CT system compared with the 16-slice multi-detector CT. For CTGIs rated as more complex, the radiation exposure of the radiologist performing the procedure was statistically significantly higher, with the exception of the left hand. A statistically significantly lower median whole-body dose was measured for inexperienced compared with experienced radiologists. However, a few dose measurements of more than 1 mSv were found at the right hand.

CONCLUSIONS

Radiation exposure measured during CTGIs is low (<50 μSv). Because the radiation dose was higher in more-complex interventions and for 16-slice multi-detector row CT, inexperienced radiologists should focus on less-complex procedures.

Brain radiation doses to patients in an interventional neuroradiology laboratory

BACKGROUND AND PURPOSE

In 2011, the International Commission on Radiologic Protection established an absorbed-dose threshold to the brain of 0.5 Gy as likely to produce cerebrovascular disease. In this paper, the authors investigated the brain doses delivered to patients during clinical neuroradiology procedures in a university hospital.

MATERIALS AND METHODS

The radiation dose delivered to the brain was investigated in 99 diagnostic and therapeutic interventional neuroradiology procedures. Brain doses were calculated in a mathematic model of an adult standard anthropomorphic phantom by using the technical and radiation dose data of an x-ray biplane system submitted to regular quality controls and calibration programs.

RESULTS

For cerebral embolizations, brain doses resulted in a maximum value of 1.7 Gy, with an average value of 500 mGy. Median and third quartile resulted in 400 and 856 mGy, respectively. For cerebral angiography, the average dose in the brain was 100 mGy.

CONCLUSIONS

This work supports the International Commission on Radiologic Protection recommendation on enhancing optimization when doses to the brain could be higher than 0.5 Gy. Radiation doses should be recorded for all patients and kept as low as reasonably achievable. For pediatric patients and young adults, an individual evaluation of brain doses could be appropriate.

Are we effectively informing patients? A quantitative analysis of on-line patient education resources from the American Society of Neuroradiology

BACKGROUND AND PURPOSE

The ubiquitous use of the Internet by the public in an attempt to better understand their health care requires the on-line resources written at an appropriate level to maximize comprehension for the average user. The National Institutes of Health and the American Medical Association recommend on-line patient education resources written at a third-to-seventh grade level. We evaluated the readability of the patient education resources provided on the Web site of the American Society of Neuroradiology (http://www.asnr.org/patientinfo/).

MATERIALS AND METHODS

All patient education material from the ASNR Web site and the Society of Neurointerventional Surgery Web site were downloaded and evaluated with the computer software, Readability Studio Professional Edition, by using 10 quantitative readability scales: the Flesch Reading Ease, Flesch-Kincaid Grade Level, Simple Measure of Gobbledygook, Coleman-Liau Index, Gunning Fog Index, New Dale-Chall, FORCAST Formula, Fry Graph, Raygor Reading Estimate, and New Fog Count. An unpaired t test was used to compare the readability level of resources available on the American Society of Neuroradiology and the Society of Neurointerventional Surgery Web sites.

RESULTS

The 20 individual patient education articles were written at a 13.9 ± 1.4 grade level with only 5% written at <11th grade level. There was no statistical difference between the level of readability of the resources on the American Society of Neuroradiology and Society of Neurointerventional Surgery Web sites.

CONCLUSIONS

The patient education resources on these Web sites fail to meet the guidelines of the National Institutes of Health and American Medical Association. Members of the public may fail to fully understand these resources and would benefit from revisions that result in more comprehensible information cast in simpler language.

Chest radiograph-based algorithm for managing malfunctioning ports

PURPOSE

To evaluate a chest x-ray-based algorithm for managing malfunctioning ports.

MATERIALS AND METHODS

A review of interventional radiology procedures on malfunctioning ports during the period 2000-2012 was performed. Events were divided into two periods: before and after implementation of an algorithm beginning with tip position evaluation using a chest x-ray. Time to return to usability, frequency of interventions to restore function, and frequency of malfunctioning ports remaining in use after the procedure were calculated.

RESULTS

The review included 303 procedures before implementation of the algorithm on 237 access sites in 227 patients (mean age, 56 y; 38% male) and 155 procedures after implementation of the algorithm on 131 access sites in 130 patients (mean age, 55 y; 35% male). Implementation of the algorithm was associated with significantly fewer repeat checks on the same access (27% before algorithm, 9% after algorithm, P < .001) and reduced frequency of a malfunctioning port remaining in use after the interventional radiology procedure (43% before algorithm to 14% after algorithm, P < .001). Median time from consultation to revision was significantly less after implementing the algorithm (13 days before algorithm, 1 day after algorithm, P < .001). Median time from consultation to port usability was also less after implementing the algorithm (2.7 days before algorithm, 1 day after algorithm, P < .001).

CONCLUSIONS

Implementation of the algorithm was associated with significantly less frequent repeat procedures on the same port and a lower frequency of malfunctioning ports remaining in place. Use of the algorithm was associated with significantly reduced time from consultation to revision and to return to usability. These findings suggest the algorithm allows triage of patients with malfunctioning ports to the appropriate intervention before undergoing a procedure.

Quality of life assessment in interventional radiology

The aim of this review was to describe quality of life (QoL) questionnaires relevant to interventional radiology. Interventional radiologists perform a large number of palliative procedures. The effect of these therapies on QoL is important. This is particularly true for cancer therapies where procedures with marginal survival benefits may result in tremendous QoL benefits. Image-guided minimally invasive procedures should be compared to invasive procedures, with respect to QoL, as part of comparative effectiveness assessment. A large number of questionnaires have been validated for measurement of overall and disease-specific quality of life. Use of applicable QoL assessments can aid in evaluating clinical outcomes and help to further substantiate the need for minimally invasive image-guided procedures.

Realism, criterion validity, and training capability of simulated diagnostic cerebral angiography

Computer-based simulation is increasingly used in medical education for training, assessment, credentialing, and practice. Compared to medical specialties such as anesthesiology and general surgery, the adoption of simulation for neurointerventional training has been slow. This may be due to the limited number of neurointerventional simulators available and the lack of research assessing their validity and training capability. The objective of this study was to assess the realism, validity, and training capability of computer-based simulation for diagnostic cerebral angiography using a commercially available simulator called the ANGIO Mentor Express.

Development of workflow task analysis during cerebral diagnostic angiographies: time-based comparison of junior and senior tasks

OBJECTIVE

Assessing neuroradiologists' skills in the operating room (OR) is difficult and often subjective. This study used a workflow time-based task analysis approach while performing cerebral angiography.

METHODS

Eight angiographies performed by a senior neuroradiologist and eight performed by a junior neuroradiologist were compared. Dedicated software with specific terminology was used to record the tasks. Procedures were subdivided into phases, each comprising multiple tasks. Each task was defined as a triplet, associating an action, an instrument and an anatomical structure. The duration of each task was the metric. Total duration of the procedure, task duration and the number of times a task was repeated were identified. The focus was on tasks using fluoroscopy and for moving the X-ray table/tube.

RESULTS

The total duration of tasks to complete the entire procedure was longer for the junior operators than for the seniors (P=0.012). The mean duration per task during the navigation phase was 86s for the juniors and 43s for the seniors (P=0.002). The total and mean durations of tasks involving the use of fluoroscopy were also longer for the juniors (P=0.002 and P=0.033, respectively). For tasks involving the table/tube, the total and mean durations were again longer for the juniors (P=0.019 and P=0.082, respectively).

CONCLUSION

This approach allows reliable skill assessment in the radiology OR and comparison of junior and senior competencies during cerebral diagnostic angiography. This new tool can improve the quality and safety of procedures, and facilitate the learning process for neuroradiologists.

Assessment of eye and body dose for interventional radiologists, cardiologists, and other interventional staff

A dose limit for the eye of 20 mSv, as proposed by the ICRP, could be exceeded by interventional clinicians. Data on eye dose levels for interventional radiologists and cardiologists provided by medical physicists from hospitals around the UK have been collated. The results indicate that most hospitals would require one or more interventional clinicians to be classified and several would have exceeded a 20 mSv limit. Dose data in the literature have been reviewed to derive factors that might be used to predict eye dose levels based on dose per procedure or kerma-area product workload. These could be used in prior risk assessments to establish monitoring practice. An alternative approach to personnel dose monitoring in radiology applications using a collar dosimeter worn outside the lead apron as the first dosimeter is proposed. The collar dosimeter would provide an assessment of eye dose in terms of Hp(3) and body dose in terms of Hp(10), which could be divided by ten to provide an assessment of effective dose. If Hp(3) exceeded 1 mSv per month, regular monitoring with a head dosimeter would be recommended, and if Hp(10) exceeded 2 mSv per month, then an under-apron dosimeter should also be worn.

Variation in radiographic protocols in paediatric interventional cardiology

The aim of this work is to determine current radiographic protocols in paediatric interventional cardiology (IC) in the UK and Ireland. To do this we investigated which imaging parameters/protocols are commonly used in IC in different hospitals, to identify if a standard technique is used and illustrate any variation in practice. A questionnaire was sent to all hospitals in the UK and Ireland which perform paediatric IC to obtain information on techniques used in each clinical department and on the range of clinical examinations performed. Ethical and research governance approval was sought from the Office for Research Ethics Committees Northern Ireland and the individual trusts. A response rate of 79% was achieved, and a wide variation in technique was found between hospitals. The main differences in technique involved variations in the use of an anti-scatter grid and the use of additional filtration to the radiation beam, frame rates for digital acquisition and pre-programmed projections/paediatric specific programming in the equipment. We conclude that there is no standard protocol for carrying out paediatric IC in the UK or Ireland. Each hospital carries out the IC procedure according to its own local protocols resulting in a wide variation in radiation dose.

Quantitative evaluation of light scattering intensities of the crystalline lens for radiation related minimal change in interventional radiologists: a cross-sectional pilot study

To evaluate low-dose X-ray radiation effects on the eye by measuring the amount of light scattering in specific regions of the lens, we compared exposed subjects (interventional radiologists) with unexposed subjects (employees of medical service companies), as a pilot study. According to numerous exclusionary rules, subjects with confounding variables contributing to cataract formation were excluded. Left eye examinations were performed on 68 exposed subjects and 171 unexposed subjects. The eye examinations consisted of an initial screening examination, followed by Scheimpflug imaging of the lens using an anterior eye segment analysis system. The subjects were assessed for the quantity of light scattering intensities found in each of the six layers of the lens. Multiple stepwise regression analyses were performed with the stepwise regression for six variables: age, radiation exposure, smoking, drinking, wearing glasses and workplace. In addition, an age-matched comparison between exposed and unexposed subjects was performed. Minimal increased light scattering intensity in the posterior subcapsular region showed statistical significance. Our results indicate that occupational radiation exposure in interventional radiologists may affect the posterior subcapsular region of the lens. Since by its very nature this retrospective study had many limitations, further well-designed studies concerning minimal radiation-related lens changes should be carried out in a low-dose exposure group.

How often are x-rays used as diagnostic tool by healthcare providers in the Mazovian province of Poland

BACKGROUND

Within the medical facilities provided by state healthcare services, a universally applied technique for patient diagnosis and treatment relies on ionising radiation; for example in radiotherapy and X-ray (ie. examination). Human exposure to such radiation is not however entirely free of associated health risks.

OBJECTIVES

To determine and estimate the numbers and types of X-ray based medical procedures that are performed in general and dental radiography, mammography and computer tomography on patients from the Mazovian province in Poland, which included children, women and men subjects.

MATERIAL AND METHODS

The numbers of patient subjects undergoing X-rays was estimated by surveying the patient intake in X-ray testing rooms within the healthcare facilities of the Mazovian province. Questionnaires were either dispatched by mail to such healthcare centres or were completed by the X-ray operating staff during the testing of quality control. Results so obtained from the latter, were compared to entries from the X-ray rooms' register

RESULTS

During 2009, the number of X-rays performed were 7612046 equivalent to 1460 examinations per 1000 inhabitants. The majority were done on women ie. 3847961 (50.55%), followed by 3193781 (41.96%) on men and 570 304 (7.49%) for children.

CONCLUSIONS

Results indicated that the predominating medical procedure used of this type, was for making general diagnoses; especially through using chest radiography. Others included, in descending order; dental X-ray (mainly intra-oral examination), computer tomography (mainly CT head examinations) and mammography procedures. It was also found that the annual numbers of having X-rays has increased compared to previous years.

Radiation exposure in interventional procedures

The aim of this study was to estimate radiation doses patients and staff are exposed to during interventional procedures (IPs), compare them with the international diagnostic reference levels and to develop initial National Diagnostic Reference Levels. The IP survey was undertaken as the initial task of which, retrospective data were collected from the only four Kenyan hospitals carrying out interventional radiology and cardiology procedures at the time of the study. Real-time measurement of radiation dose to patients and staff during these procedures was done. To the patients, kerma-area product (KAP) and fluoroscopy time measurements were done using an in-built KAP meter, while peak skin dose (PSD) was measured using slow Extended Dose Range (EDR2(®)) radiographic films. The staff occupational doses were measured using individual thermoluminescence dosemeters. The maximum and minimum KAP values were found to be 137.1 and 4.2 Gy cm(2), while the measured PSD values were 740 and 52 mGy, respectively. The fluoroscopic time range was between 3.3 and 70 min. The staff doses per procedure ranged between 0.05 and 1.41 mSv for medical doctors, 0.03 and 1.16 mSv for nurses, 0.04 and 0.78 mSv for radiographers and 0.04 and 0.88 mSv for clinical staff. The measured patient PSDs were within the threshold limit for skin injuries. However, with the current few IP specialists, an annual increase in workload as determined in the study will result in the International Commission on Radiation Protection annual eye lens dose limit being exceeded by 10 %. A concerted effort is required to contain these dose levels through use of protective gear, optimisation of practice and justification.

Eye lens dosimetry in interventional cardiology: results of staff dose measurements and link to patient dose levels

Workers involved in interventional cardiology procedures receive high eye lens dose if protection is not used. Currently, there is no suitable method for routine use for the measurement of eye dose. Since most angiography machines are equipped with suitable patient dosemeters, deriving factors linking staff eye doses to the patient doses can be helpful. In this study the patient kerma-area product, cumulative dose at an interventional reference point and eye dose in terms of Hp(3) of the cardiologists, nurses and radiographers for interventional cardiology procedures have been measured. Correlations between the patient dose and the staff eye dose were obtained. The mean eye dose was 121 µSv for the first operator, 33 µSv for the second operator/nurse and 12 µSv for radiographer. Normalised eye lens doses per unit kerma-area product were 0.94 µSv Gy⁻¹ cm⁻² for the first operator, 0.33 µSv Gy⁻¹ cm⁻² for the second operator/nurse and 0.16 µSv Gy⁻¹ cm⁻² for radiographers. Statistical analysis indicated that there is a weak but significant (p < 0.01) correlation between the eye dose and the kerma-area product for all three staff categories. These values are based on a local practice and may provide useful reference for other studies for validation and for wider utilisation in assessing the eye dose using patient dose values.

Practice patterns and opening pressure measurements using fluoroscopically guided lumbar puncture

BACKGROUND AND PURPOSE

Evidenced-based protocols for fluoroscopically guided LP do not exist. This study analyzed the fluoroscopically guided LP techniques currently used by practicing neuroradiologists.

MATERIALS AND METHODS

An anonymous Web-based survey was e-mailed to members of ASNR. The results were compiled and tabulated on a spreadsheet.

RESULTS

A total of 577 neuroradiologists completed the survey. Most neuroradiologists perform fluoroscopically guided LPs with the patient in the prone position by using a 22-ga needle at the L2-L3 or L3-L4 intervertebral space. The OP measurement technique is quite variable. Only a minority of patients are rotated to the left LD position for OP measurement. Most neuroradiologists observe patients for 1-2 hours after the procedure and require strict bed rest.

CONCLUSIONS

Most neuroradiologists have similar protocols for thecal sac puncture. Normative adult OP data exist only for the LD position, and the accuracy of prone OP measurements is not known. We found that the OP measurement technique is not consistent and a standard protocol is warranted.

Exposure of the Swiss population by medical x-rays: 2008 review

Nationwide surveys on radiation dose to the population from medical radiology are recommended in order to follow the trends in population exposure and ensure radiation protection.The last survey in Switzerland was conducted in 1998,and the annual effective dose from medical radiology was estimated to be 1 mSv y j(-1) per capita. The purpose of this work was to follow the trends in diagnostic radiology between 1998 and 2008 in Switzerland and determine the contribution of different modalities and types of examinations to the collective effective dose from medical x-rays. For this reason, an online database(www.raddose.ch) was developed. All healthcare providers who hold a license to run an x-ray unit in the country were invited to participate in the survey. More than 225 examinations, covering eight radiological modalities, were included in the survey. The average effective dose for each examination was reassessed. Data from about 3,500 users were collected (42% response rate). The survey showed that the annual effective dose was 1.2 mSv/capita in 2008. The most frequent examinations are conventional and dental radiographies (88%). The contribution of computed tomography was only 6% in terms of examination frequency but 68% in terms of effective dose. The comparison with other countries showed that the effective dose per capita in Switzerland was in the same range as in other countries with similar healthcare systems, although the annual number of examinations performed in Switzerland was higher.

An audit of diagnostic reference levels in interventional cardiology and radiology: are there differences between academic and non-academic centres?

A wide variation in patient exposure has been observed in interventional radiology and cardiology. The purpose of this study was to investigate the patient dose from fluoroscopy-guided procedures performed in non-academic centres when compared with academic centres. Four procedures (coronary angiography, percutaneous coronary intervention, angiography of the lower limbs and percutaneous transluminal angioplasty of the lower limbs) were evaluated. Data on the dose-area product, fluoroscopy time and number of images for 1000 procedures were obtained from 23 non-academic centres and compared with data from 5 academic centres. No differences were found for cardiology procedures performed in non-academic centres versus academic ones. However, significantly lower doses were delivered to patients for procedures of the lower limbs when they were performed in non-academic centres. This may be due to more complex procedures performed in the academic centres. Comparison between the centres showed a great variation in the patient dose for these lower limb procedures.

Status of radiation protection in interventional cardiology in four East European countries

Level of staff and patient radiation protection in interventional cardiology in four counties (Bosnia and Herzegovina, Croatia, Montenegro and Serbia) as a part of International Atomic Energy Agency project (RER/9/093) are presented. Patient doses were assessed in terms of air kerma area product (KAP), peak skin dose (PSD) or air kerma at interventional reference point (K(IRP)). Results were available from nine hospitals: 775 patients for KAP, 157 for PSD and 437 for K(IRP). Eight centres reported KAP >100 Gy cm(2) and five centres reported values >200 Gy cm(2). From patients monitored in terms of PSD, 14 (9 %) had PSD >2 Gy and 6 (3 %) patients from those monitored in terms of K(IRP) had value >5 Gy, indicating risk of skin injury. The results indicate need for optimisation and dose monitoring in complex fluoroscopically guided cardiology interventions.

CT fluoroscopy-guided vs. multislice CT biopsy mode-guided lung biopsies: accuracy, complications and radiation dose

BACKGROUND

The aim of this retrospective study was to compare the diagnostic accuracy, the frequency of complications, the duration of the interventions and the radiation doses of CT fluoroscopy (CTF) guided biopsies of lung lesions with those of multislice CT (MS-CT) biopsy mode-guided biopsies.

METHODS

Data and images from 124 consecutive patients undergoing CTF-guided lung biopsy (group A) and 132 MS-CT-biopsy mode-guided lung biopsy (group B) were reviewed. CTF-guided biopsies were performed on a Siemens Emotion 6 CT scanner with intermittent or continuous CT-fluoroscopy, MS-CT biopsy mode-guided biopsies were performed on a Siemens Emotion 16 CT scanner. All biopsies were performed with a coaxial needle technique.

RESULTS

The two groups (A vs. B) did not differ significantly regarding sensitivity (95.5% vs. 95.9%), specificity (96.7% vs. 95.5%), negative predictive value (87.9% vs. 84%) or positive predictive value (98.8% vs. 98.9%). Pneumothorax was observed in 30.0% and 32.5% of the patients, respectively. Chest tube placement was necessary in 4% (group A) and 13% (group B) of the patients. The duration of the intervention was significantly longer in group A (median 37 min vs. 32 min, p=0.04). The mean CT dose index (CTDI) was 422 in group A and 36.3 in group B (p<0.001).

CONCLUSION

Compared to CTF-guided biopsies, chest biopsies using the MS-CT biopsy mode show dramatically lower CTDI levels. Although the diagnostic yield of the procedures do not differ significantly, biopsies using the MS-CT-biopsy mode have a three-fold higher rate of chest tube placement.

Enhancing the case log by coding the level of trainee participation in vascular interventional radiology procedures

OBJECTIVE

The purpose of this article is to describe a new method for coding trainee participation in vascular interventional radiology procedures.

MATERIALS AND METHODS

From July 2008 through June 2009, all interventional radiology fellows maintained an enhanced case log at our institution; 748 unique cases were logged by procedure type, supervising physician, and level of participation in the case. Level of participation was classified on a 5-point scale that included designations for observation, first assistant, performance of basic techniques, performance of advanced techniques, and primary operation. Descriptive statistics of participation scores were calculated for each quarter and were analyzed by procedure type and by teaching faculty member.

RESULTS

As expected, analysis by procedure type showed that average participation scores increased from one quarter to the next in most cases. By the fourth quarter, the modal participation score was 5, indicating primary operation or performance of multiple critical steps. Analysis by teaching faculty member revealed three patterns: those attending physicians facilitating increasing levels of participation in every quarter, those facilitating maximal growth within the first 6 months, and those with irregular trainee participation profiles.

CONCLUSION

Data from a 5-point participation scale add information to the procedure case log that could be used to quantitatively track the technical progress of trainees while providing education quality feedback to both teaching physicians and program directors.

CT-guided injection of the anterior and middle scalene muscles: technique and complications

BACKGROUND AND PURPOSE

Anterior scalene block is a helpful diagnostic test for NTOS and a good predictor of surgical outcome. The purpose of this study was to describe the technique, success rate, and complications associated with CT-guided anesthetic and botulinum toxin injection of the ASM/MSM in patients with NTOS symptoms.

MATERIALS AND METHODS

One hundred six participants (mean age, 41.5 ± 10 years; 80 women) were identified via a retrospective review of medical records for CT-guided scalene blocks. The procedure was evaluated regarding the technical success, defined as satisfactory detection of the ASM/MSM; intramuscular needle placement; intramuscular injection of contrast; appropriate delivery of medication; and frequency of unintended BP block or other complications. We also determined the outcome of patients who underwent surgery following the block.

RESULTS

Study participants underwent 146 scalene injections, 83 blocks, and 63 chemodenervations, which were included in this investigation. In all cases, detection of the ASM/MSM and intramuscular needle placement was satisfactory. Postprocedural complications included 5 (3.4%) temporary BP blocks, 1 patient with (0.7%) Horner sign, 7 (4.8%) needle-induced pain reports, 1 (0.7%) case of dysphagia, and 2 (1.4%) instances of muscle weakness. There were no major complications reported. The rate of good outcome following surgery was the same in patients with positive versus negative blocks, 30/43 (70%) versus 5/7 (71%), respectively.

CONCLUSIONS

CT guidance is a useful adjunct in performing accurate ASM/MSM blocks with a low rate of minor complications.

Biological and physical methods for risk estimation in interventional radiology: a detrimental effect approach

Interventional radiologists and staff members are frequently exposed to the effects of direct and scattered radiation, which undergo in deterministic effects (radiodermitis, aged skin, cataracts, telangiectasia in nasal region, vasocellular epitelioms, hands depilation) and/or stochastic ones (cancer incidence). A methodology has been proposed for estimating the radiation risk or detriment from a group of six exposed interventional radiologists of the Hospital Universitario La Fe (Valencia, Spain), which had developed general exposition symptoms attributable to deterministic effects of ionizing radiation. Equivalent doses have been periodically registered using termoluminiscence dosimeters (TLD's) and wrist dosimeters, H(p)(10) and H(p)(0.07), respectively, and estimated through the observation of translocations in lymphocytes of peripheral blood (biological methods), by extrapolating the yield of translocations to their respective dose-effect curves. The software RADRISK has been applied for estimating radiation risks in these occupational radiation exposures. The minimum and maximum average excess ratio for skin cancer has been, using wrist physical doses, of [1.03 × 10(-3), 5.06 × 10(-2)], concluding that there is not an increased risk of skin cancer incidence. The minimum and maximum average excess ratio for leukemia has been, using TLD physical doses, of [7.84 × 10(-2), 3.36 × 10(-1)], and using biological doses, of [1.40 × 10(-1), 1.51], which is considerably higher than incidence rates, showing an excess radio-induced risk of leukemia in the group under study. Finally, the maximum radiological detriment in the group, evaluated as the total number of radio-induced cancers using physical dosimetry, has been of 2.18 per 1000 person-year (skin and leukemia), and using biological dosimetry of 9.20 per 1000 PY (leukemia). As a conclusion, this study has provided an assessment of the non-deterministic effects (rate of radio-induced cancer incidence) attributable to the group under study due to their professional activity.

Dosimetric data and radiation risk analysis for new procedures in interventional cardiology

The purpose of this study was to evaluate radiation doses to the patients and operators during interventional cardiology procedures, with a particular focus on the transcatheter aortic valve implantation (TAVI). Patient doses for 5549 diagnostic and therapeutic procedures and 76 TAVI were examined, as well as occupational doses to Cardiology Department operators. The average patient dose for TAVI was double that of PTCA and six times higher than a simple CA; statistically significant differences were shown in the average patient dose for both transfemoral and transapical access; the measurements show a corresponding increase in the average occupational dose for the cardiologist. Interventional cardiology could increase the collective dose and occupationally exposed worker doses; this increase could be significant if the use of certain procedures is extended to younger people; particular attention in the choice of procedure, optimisation and staff education and organisation is therefore suggested.

CT fluoroscopy-guided lung biopsy versus conventional CT-guided lung biopsy: a prospective controlled study to assess radiation doses and diagnostic performance

OBJECTIVE

We evaluated radiation doses, complication rates, and diagnostic accuracy for CT-guided percutaneous needle aspiration biopsy (NAB) procedures of pulmonary lesions performed with or without fluoroscopic guidance.

METHODS

A total of 142 patients were prospectively enrolled to receive CT-guided NAB with (Group I, n = 72) or without (Group II, n = 70) fluoroscopic guidance. Outcome measurements were patient and doctor radiation dose, and complication rate. Sensitivity, specificity and accuracy were calculated based on 123 NAB results.

RESULTS

The mean estimated effective patient radiation dose was 6.53 mSv in Group I and 2.72 mSv in Group II (p < 0.001). The mean estimated effective doctor dose was 0.054 mSv in Group I and 0.029 mSv in Group II (p < 0.001). The complication rate was significantly different between the two groups (13.4% versus 31.4%, p = 0.012). Sensitivity, specificity and accuracy for diagnosing pulmonary lesions were 97.8%, 100% and 98.4% in group I and 95.3%, 100% and 89.5% in group II (p > 0.05).

CONCLUSIONS

CT fluoroscopy-guided NAB of pulmonary lesions provides high diagnostic accuracy and can be performed with significantly fewer complications. However, radiation exposure to both patient and doctor were significantly higher than conventional CT-guided NAB.

Fluoroscopy-guided procedures in cardiology: is patient exposure being reduced over time?

The number of fluoroscopy-guided procedures in cardiology is increasing over time and it is appropriate to wonder whether technological progress or change of techniques is influencing patient exposure. The aim of this study is to examine whether patient dose has been decreasing over the years. Patient dose data of more than 7700 procedures were collected from two cardiology centres. A steady increase in the patient dose over the years was observed in both the centres for the two cardiological procedures included in this study. Significant increase in dose was also observed after the installation of a flat-panel detector. The increasing use of radial access may lead to an increase in the patient exposure. The monitoring of dose data over time showed a considerable increase in the patient exposure over time. Actions have to be taken towards dose reduction in both the centres.

Does a flat panel detector reduce the patient radiation dose in interventional cardiology?

An internal audit has been performed to evaluate the patient radiation dose in the clinical use of X-ray cardiac flat panel detector (FPD) systems. Fluoroscopy and image acquisition (cine mode) programs are optimised for low-dose settings. The diagnostic and therapeutic interventional cardiac procedures are performed at 6 pulse s(-1) for fluoroscopy and 15 frames s(-1) for image acquisition. The FPD entrance dose is configured for 29 nGy pulse(-1) in the fluoroscopy mode and 0.10 microGy frame(-1) in the cine mode. From the data collected, the following local reference levels for coronary angiography and angioplasty have been obtained: kerma-area products 23 and 44 Gy cm(2), cumulative doses 376 and 776 mGy, fluoroscopy times 5 and 15.5 min and cine images 617 and 1163 images.

Patient peak skin doses from cardiac interventional procedures

Interventional cardiac procedures not only lead to significant effective doses for the patient but also can potentially cause deterministic effects on the patient's skin. Information about the peak (maximal) skin doses (PSD) received by patients during percutaneous transluminal coronary angioplasty procedures were collected from three cardiac catheter rooms. Cumulative dose at the interventional reference point (CD(IRP)) was collected for 161 patients and for 16 patients PSD was determined using Gafchromic dosimetry films. The comparison showed that CD(IRP) readings give a useful but conservative estimation of patient peak skin dose as it can lead to a significant overestimation. The median and third quartile values of CD(IRP) were 0.64 and 0.92 Gy, respectively. The 2 Gy threshold for deterministic effects was exceeded in nine patients. A good correlation was found between CD(IRP) and kerma area product measurements while the correlation with fluorography time was very weak.