Computed Tomography Suite Research Articles

The utility of computed tomography at a district-level public hospital in Cape Town.

Computed tomography (CT) has become an invaluable aid in medical diagnostic workup, and its global usage has been shown to be consistently increasing across all departments. While typically located in regional or central hospitals in South Africa, its recent introduction at the district level has many foreseeable benefits. We evaluated its utility at one of the first district hospitals in the Western Cape to obtain a CT suite. This study aimed to describe the type of CT scans ordered, the clinical indications, the prevalence of significant abnormal findings and the agreement between the clinical opinion and radiological diagnosis. A descriptive cross-sectional study was conducted over a 1-year period at Khayelitsha Hospital, an entry-level hospital just outside of Cape Town. A total of 3242 CT scans were analysed. The mean age of patients was 46 years; 51.4% were males. A mean of 13 scans were performed per working day. The head and neck area were the most scanned region (n= 1841, 52.3%). Predominantly requested by the Emergency Centre (n= 1382, 42.6%), indications were mainly for general medical conditions workup (n= 2151, 66.4%). Most scans showed abnormalities (n= 2710, 83.6%), with 2115 (65.2%) considered relevant ('positive yield'). Clinical and CT diagnoses agreed in 1610 (49.7%) cases. Computed tomography usage at the district level demonstrated positive yield rates comparable to that of tertiary centres. This implies an appropriate utilisation of the service with a potential decrease in the burden on the referral centre.Contribution:Computed tomography scanners at district-level facilities are appropriately utilised and can provide greater access to care while potentially decreasing the burden on referral centres.

Enhancing blood pressure management protocol implementation in patients with acute intracerebral haemorrhage through a nursing-led approach: A retrospective cohort study.

To evaluate the impact of nurse care changes in implementing a blood pressure management protocol on achieving rapid, intensive and sustained blood pressure reduction in acute intracerebral haemorrhage patients. Retrospective cohort study of prospectively collected data over 6 years. Intracerebral haemorrhage patients within 6 h and systolic blood pressure ≥ 150 mmHg followed a rapid (starting treatment at computed tomography suite with a target achievement goal of ≤60 min), intensive (target systolic blood pressure < 140 mmHg) and sustained (maintaining target stability for 24 h) blood pressure management plan. We differentiated six periods: P1, stroke nurse at computed tomography suite (baseline period); P2, antihypertensive titration by stroke nurse; P3, retraining by neurologists; P4, integration of a stroke advanced practice nurse; P5, after COVID-19 impact; and P6, retraining by stroke advanced practice nurse. Outcomes included first-hour target achievement (primary outcome), tomography-to-treatment and treatment-to-target times, first-hour maximum dose of antihypertensive treatment and 6-h and 24-h systolic blood pressure variability. Compared to P1, antihypertensive titration by stroke nurses (P2) reduced treatment-to-target time and increased the rate of first-hour target achievement, retraining of stroke nurses by neurologists (P3) maintained a higher rate of first-hour target achievement and the integration of a stroke advanced practice nurse (P4) reduced both 6-h and 24-h systolic blood pressure variability. However, 6-h systolic blood pressure variability increased from P4 to P5 following the impact of the COVID-19 pandemic. Finally, compared to P1, retraining of stroke nurses by stroke advanced practice nurse (P6) reduced tomography-to-treatment time and increased the first-hour maximum dose of antihypertensive treatment. Changes in nursing care and continuous education can significantly enhance the time metrics and blood pressure outcomes in acute intracerebral haemorrhage patients. STROBE guidelines. No Patient or Public Contribution.

Infection prevention and control in CT Part 1: An Australian study of roles, responsibilities and practices

IntroductionThe computed tomography (CT) suite presents Infection Prevention and Control (IPC) risks for staff and patients. This is the first of a two-part series on IPC in the CT setting and reports on Australian baseline data related to intravenous contrast media administration and the use of power injectors in the CT suite, including knowledge sources related to the delivery of contrast media. The second part provides insights into CT staff's perceptions of high-risk scenarios for non-adherence to standard or transmission-based precautions. MethodsThe study employed an online survey design, directed at radiographers and radiology nurses working in Australia. The survey included questions relating to CT workplace staffing and equipment, contrast media use and occupational roles, and knowledge sources used for infection control and contrast injectors. ResultsOverall, 160 study participants completed the survey (radiographers: n = 138, 86.3%; nurses: n = 22, 13.7%). Differences were identified between public and private practice. Public hospitals completed more contrast-enhanced scans, and with dual injecting systems, operated and cleaned by radiographers and nurses. Private clinics generally used single-system, power injectors. Radiographers and nurses relied heavily on their colleagues and product guidelines for IPC information. IPC teams were uncommon in private clinics, very common in public departments and 50% of respondents had undertaken IPC training in the last 12 months. ConclusionInsights into use and duties of professionals delivering intravenous contrast media administration using power injectors in the CT suite will help to inform decision-making processes on IPC education strategies and map risk. Implication for practiceFuture research should focus on how radiology workers in CT perceive IPC risk and/or might vary from best practice, which has direct clinical implications for safety if contamination, or incorrect information is routinely applied.

Infection prevention and control in computed tomography: creating a national survey

BackgroundInfection prevention and control (IPC) is essential for quality healthcare, with healthcare associated infections (HAI) a known risk to patients requiring medical imaging (MI). To date, few papers have adopted a national approach to understanding or benchmarking the knowledge of, attitudes toward, and practice (KAP) of IPC in the context of MI and no validated surveys or scales are identified in the literature. The Computed Tomography (CT) suite is a unique MI environment where radiographers deliver prescription medicines to patients via intravenous (IV) means through an injector system. This paper describes the development of a survey that informs the use of IPC processes in the CT suite. MethodsStandard Precautions via current national guidelines formed the benchmark of the survey, with a KAP survey used as the framework to explore IPC. The questions and associated responses are developed based on the National Health and Medical Research Council (NHMRC) guidelines, industry/professional protocols and adapted to the equipment and practices commonly used in the CT suite of MI departments by radiographers and nurses. ResultsKey survey development steps are described to include the justification of the benchmarking source, the survey framework and design. Detailed information is given to show the evolution of truth statements and sources, KAP question variations, and rationales for the methodology of question responses. National guidelines are mapped to survey questions and responses and pilot testing reflections are included. ConclusionThis paper reports on the construction of a standardised KAP survey for IPC specific to the CT suite in the Australian healthcare setting. The survey is ready for dissemination amongst MI departments. Documented use will aid validation and reliability as a survey tool to measure and map IPC specifically in relation to IV contrast administration.

Intraprocedural, Intra-Arterial CT Foot Perfusion Examination for Assessment of Endovascular Therapy in Patients With Critical Limb Ischemia: A Prospective Pilot Study.

Current techniques to evaluate computed tomography (CT) foot perfusion in patients with critical limb ischemia use high contrast doses and cannot be used during endovascular procedures. CT perfusion of the foot with intra-arterial contrast injection during endovascular treatment in a hybrid angiography CT suite might solve these problems. The main objective of this study was to evaluate whether intra-arterial CT foot perfusion using a hybrid CT angiosystem is feasible during endovascular treatment for critical limb ischemia. This prospective pilot study investigated intraprocedural, intra-arterial CT perfusion of the foot using a hybrid CT angiosystem in 12 patients before and after endovascular treatment for critical limb ischemia. Time to peak (TTP) and arterial blood flow were measured before and after treatment and compared using a paired t test. All 24 CT perfusion maps could be calculated adequately. The contrast volume used for one perfusion CT scan was 4.8 ml. The mean TTP before treatment was 12.8 seconds (standard deviation [SD] 2.8) and the mean TTP posttreatment was 8.4 seconds (SD 1.7), this difference being statistically significant (p=.001). Tendency toward increased blood flow after treatment, 340 ml/min/100 ml (SD 174) vs 514 ml/min/100 ml (SD 366) was noticed (p=.104). The mean effective radiation dose was 0.145 mSv per scan. Computed tomography perfusion of the foot with low contrast dose intra-arterial contrast injection during endovascular treatment in a hybrid angiography CT suite is a feasible technique. Intra-arterial CT foot perfusion using a hybrid CT-angiography system is a feasible new technique during endovascular therapy for critical limb ischemia to assess the results of the treament. Future research is necessary in defining endpoints of endovascular treatment and establishing its role in limb salvage prognostication.

Telestroke Process at a Community Hospital: A Quality Improvement Project

IntroductionAn updated stroke process was designed and implemented at an Acute Stroke Ready community hospital that relies on telestroke services. The objectives of the current quality improvement project were to describe the updates to the stroke process and compare pre- and postintervention data on nurse-driven elements of the process, namely telestroke notification and neurologist assessment. MethodsOur multidisciplinary team reviewed quality data over several months to identify areas of improvement in the stroke process. Delays in door to telestroke notification and neurologist assessment were identified. A new process was developed and implemented, including e-alert notification and storing the telestroke cart in the computed tomography suite. The study period was 14 months, with nonrandomized, convenience sample data collected for 7 months before and after intervention. ResultsThere was a significant reduction in door to telestroke notification and neurologist assessment after implementing the new process. Door to telestroke notification and neurologist assessment were also strongly correlated. DiscussionThis project led to significant improvements in nurse-driven elements of the stroke process. It demonstrates effective implementation of e-alert and collaboration with telestroke services at an Acute Stroke Ready Hospital serving rural communities.

Use of a smartwatch as a remote monitoring device during transport to, and inside, a computed tomography suite.

Use of a smartwatch as a remote monitoring device during transport to, and inside, a computed tomography suite.

Novel Telephone-Based Interactive Voice Response System for Incident Reporting.

The voluntary reporting of medical errors and near misses is a well-established patient safety reporting mechanism. However, studies suggest that these incident reporting systems (IRSs) detect less than 10% of all adverse events. Improving the process of reporting can facilitate more informative and timely data capture while providing more opportunities to improve health care quality and safety. The purpose of this study was to understand the barriers to incident reporting via the existing Web-based IRS and develop solutions to increase the ease and efficiency of reporting. A survey of staff in a diagnostic imaging department in St. Catharines, Ontario was performed to identify barriers to incident reporting. Based on the barriers identified, two methods of incident reporting were tested in successive phases: (1) a phone-based voice message mailbox, in the computed tomography suite; and (2) a phone-based structured interactive voice response system (IVRS), across the entire department. We measured the rate of incident reports/day and time required to complete reports. The three most common barriers to reporting identified were lack of time, complexity of reporting system, and lack of feedback. There was a significant difference in reports per day for the IVRS (mean [M] = 3.43, standard deviation [SD] = 2.71) compared to the IRS (M = 0.99, SD = 0.55); t(31) = 4.58, p ≤ 0.00001. There was also a significant difference in the average time to make a report for the IVRS (M = 97 seconds [s], SD = 30 s) compared to the IRS (M = 644 s, SD = 90 s); t(4) =13.55, p = 0.00025. IVRS is an innovative approach to incident reporting that may prove to be more efficient than Web-based approaches and encourage higher reporting rates.

Trauma Computed Tomography in the Modern Era: Not Always Quick and Safe.

Computed tomography (CT) has emerged as the diagnostic modality of choice in trauma patients. Recent studies suggest its use in hemodynamically unstable patients is safe and potentially lifesaving; however, the incidence of adverse events (AE) during the trauma CT scanning process remains unknown. Over a 6-month period at a Level 1 trauma center, data on patients undergoing trauma CT (whole-body CT (WBCT) +/- additional CT studies) were prospectively collected. All patients requiring a trauma team activation (TTA) were included. Adverse events and specific time intervals were recorded from the time of TTA notification to the time of return to the resuscitation bay from the CT suite. Of the 94 consecutive patients included in the study, 47.9% experienced 1 or more AE. Median duration away from the resuscitation bay for all patients was 24minutes. Patients with AE spent a significantly longer time away from the resuscitation bay and had longer scan times. Vasopressor support and ongoing transfusion requirement at the time of CT scanning were associated with AE. Adverse events of varying clinical significance occur frequently in patients undergoing emergent trauma CT. A standard trauma CT protocol could improve the efficiency and safety of the scanning process.

Non-fatal Bihemispheric Penetrating Brain Injury from a Crossbow Arrow with Good Clinical Outcome: Case Report

AbstractCrossbow injuries to the head have seldom been reported in the literature, and they represent a unique type of penetrating brain injury (PBI) in which a low-velocity arrow results in an intracranial fragment larger than most high-velocity projectiles, usually with a lethal outcome. We present the case of a 34-year-old man who attempted suicide with a self-inflicted cranial injury from a crossbow arrow, with a right parietal point of entry and a palpable subcutaneous tip in the left parietal region. The emergency team reported a Glasgow coma scale (GCS) score of 15, and the patient was brought sedated and intubated. Computed tomography (CT) imaging scans showed that the arrow crossed both parietal lobes, with mild subarachnoid hemorrhage and small cerebral contusions adjacent to its intracranial path. Careful retrograde removal of the penetrating arrow was performed in the CT suite, followed by an immediate CT scan, which excluded procedure-related complications. The patient woke up easily and was discharged 3 days later with mild left hand apraxia and no other neurologic deficits. To the best of our knowledge, there are no similar case reports describing both good clinical outcome and rapid discharge after a bihemispheric PBI. Individualizing the management of each patient is therefore crucial to achieve the best possible outcome as PBI cases still represent a major challenge to practicing neurosurgeons worldwide.

Computed tomography-guided percutaneous radiofrequency and laser ablation for the treatment of osteoid osteoma - long-term follow-up from 5 to 10 years.

PurposeThe impact of computed tomography (CT)-guided, percutaneous radiofrequency ablation and interstitial laser ablation (ILA) on the management of patients with osteoid osteoma was studied. This was carried out by assessing immediate and long-term clinical outcomes, the complication rate, and repeat therapy effectiveness in recurrent patients who have already experienced percutaneous ablation.Material and methodsConsecutive patients with osteoid osteoma were assessed before the interventional treatment in a single centre from 2010 to 2015. Patient demographics, complications, and recurrence were recorded. The pain was evaluated with Visual Analogue Scale (VAS). Percutaneous procedures were performed by means of radiofrequency thermoablation or ILA. Epidural or regional anaesthesia in the CT suite was applied in all procedures. Success, whether primary or secondary, was measured as complete pain relief without evidence of recurrence after the first or second procedure, respectively. Osteoid osteoma characteristics, procedure overview, and technical success were looked for in pre-procedural and procedural scans.ResultsEighty-three per cent of osteoid osteomas were located in lower extremities, 56% of tumours were intracortical, and 83% of osteoid osteomas were extra-articular. The mean pre-procedure VAS score was 8.5 ± 0.8, while the overall primary success rate of radiofrequency thermoablation and ILA was 87.5%. No major complications were noted. The mean follow-up period for patients in was 7.5 years (5.0-10.2 years).ConclusionsPercutaneous, CT-guided thermoablation proved to be effective and should become the method of choice in osteoid osteoma treatment because of its minimal invasiveness. Our results show that there is no risk of very late recurrence after achieving primary and secondary treatment success.

Learning From Experience: “Minimizing Patient Delays in Radiology: Optimizing On-Time Starts for CT Procedures”

PurposeTo identify and analyze factors resulting in consistently delayed start times of the first outpatient procedure scheduled at 8:30 AM and to establish a standardized process to increase on time starts from 11% to greater than 50% within 20 weeks. MethodsTeam of key stakeholders were assembled and goals for quality improvement project were established. Current state analysis performed via retrospective data warehouse collection and prospective monitoring of patient arrival and throughput. On time starts defined as patient arrival into computed tomography suite within 15 minutes of scheduled time. Root cause analysis and tests of change were generated during team meetings to address factors contributing to delays. Implementation phase of new processes and tests of change occurred over 20 weeks and continuous feedback was obtained. Number of on time starts and turnaround time (TAT) was monitored and collected throughout implementation phase and post implementation (control phase) for an additional 8 weeks. ResultsCurrent state process map demonstrated a baseline cycle time of 62-133 minutes from patient check in to start time. Root cause analysis identified multiple factors including environment, people, processes and materials issues. 14 tests of change were developed, including standardization of process map with specific time allotments and role assignments for the procedural team. Mean TAT decreased from 71.5 to 21 minutes during implementation phase. Mean TAT further decreased to 15.9 minutes during control phase. Exams starting within 15 minutes of appointment time improved from 11% to 60% with significant outliers being due to patient late arrival and difficult IV access. Excluding these causes, on time starts improved to 82%. ConclusionSignificant strides in improving workflow efficiency and patient waits and delays in the procedural space of radiology departments can be achieved by selecting a well-defined specific goal and utilizing a team approach to quality improvement.

COVID-19 pneumonia: infection control protocol inside computed tomography suites

A novel coronavirus (severe acute respiratory syndrome coronavirus 2) causes a cluster of pneumonia cases in Wuhan, China. It spread rapidly and globally. CT imaging is helpful for the evaluation of the novel coronavirus disease 2019 (COVID-19) pneumonia. Infection control inside the CT suites is also important to prevent hospital-related transmission of COVID-19. We present our experience with infection control protocol for COVID-19 inside the CT suites.

Flat-panel detector CT assessment in stroke to reduce times to intra-arterial treatment: A study of multiphase computed tomography angiography in the angiography suite to bypass conventional imaging.

Bypassing the emergency department and the computed tomography suite by directly transporting to the neuroangiography suite for imaging assessment and treatment may shorten reperfusion times while maintaining proper patient selection. To determine whether flat-panel detector multiphase computed tomography angiography protocol is associated with reduced treatment times and a similar safety profile as the standard imaging protocol. Single-center prospective study of consecutive patients with anterior circulation large vessel occlusion strokes transferred to our facility for consideration of endovascular therapy from May 2016 to December 2017. Those with basilar strokes and/or presenting to the emergency department were excluded. Patients were categorized into two groups: (1) flat-panel detector CT assessment in stroke to reduce times to intra-arterial treatment group, with patients transferred directly to the suite for multiphase computed tomography angiography; and (2) patients undergoing standard protocol including computed tomography ± computed tomography angiography/CT perfusion. The groups were matched for age, baseline National Institute of Health Stroke Scale, and pretreatment glucose. Baseline characteristics, time metrics, and outcomes were compared. Out of 419 patients who underwent endovascular therapy over the study period, 210 patients fit inclusion criteria, with 54 (25.7%) in the flat-panel detector CT assessment in stroke to reduce times to intra-arterial treatment group. After matching, 49 flat-panel detector CT assessment in stroke to reduce times to intra-arterial treatment/control pairs were generated and analyzed. Baseline characteristics were well balanced. Flat-panel detector CT assessment in stroke to reduce times to intra-arterial treatment patients had significantly shorter median door-to-puncture (33 [26.5-47] vs. 55 [44.5-66] min, p < 0.001), door-to-reperfusion (85 [57.5-115.5] vs. 110 [80-153], p = 0.005) and picture-to-puncture (18 [13.5-22.5] vs. 42 [32-47.5] min, p < 0.001) times. There were no differences in rates of successful reperfusion (modified thrombolysis in cerebral infarction 2b-3, 95.9% vs. 100%, p = 0.5), parenchymal hematomas type-2 (4.1% vs. 2%, p = 1.00), good outcome (90-day modified Rankin Scale 0-2, 44.9% vs. 40.8%, p = 0.68), and 90-day mortality (14.3% vs. 22.4%, p = 0.30). Directly transferring patients to angiography and using multiphase computed tomography angiography to determine the eligibility for endovascular therapy is safe and may result in a significant reduction in treatment times. Future larger studies are warranted.

The role of imaging and other diagnostic approaches in COVID-19.

As the COVID-19 pandemic develops across the globe, a large amount of literature has been written about the different ways in which we can diagnose and investigate someone suspected of being infected with the new coronavirus. Many approaches highlight the importance of using reverse transcriptase polymerase chain reaction (RT-PCR) used in conjunction with computed tomography (CT) scans. Whilst CT scans have been shown to be useful, there are multiple risks associated with them, for example radiation exposure and the transmission risk associated with repeated use of a CT suite. Therefore, it is important to analyse their diagnostic ability and limitations and to consider other methods of diagnosing COVID-19. Additionally, RT-PCR testing can have significant rates of false negatives, indicating the importance of taking a more comprehensive diagnostic approach. Here, we aim to review and analyse this literature to compare RT-PCR, serum inflammatory biomarkers, chest radiographs, ultrasound and chest CT scanning as methods of diagnosing COVID-19, particularly in asymptomatic patients. (www.actabiomedica.it)

PET/CT-guided biopsy with respiratory motion correction

Given the ability of positron emission tomography (PET) imaging to localize malignancies in heterogeneous tumors and tumors that lack an X-ray computed tomography (CT) correlate, combined PET/CT-guided biopsy may improve the diagnostic yield of biopsies. However, PET and CT images are naturally susceptible to problems due to respiratory motion, leading to imprecise tumor localization and shape distortion. To facilitate PET/CT-guided needle biopsy, we developed and investigated the feasibility of a workflow that allows to bring PET image guidance into interventional CT suite while accounting for respiratory motion. The performance of PET/CT respiratory motion correction using registered and summed phases method was evaluated through computer simulations using the mathematical 4D extended cardiac-torso phantom, with motion simulated from real respiratory traces. The performance of PET/CT-guided biopsy procedure was evaluated through operation on a physical anthropomorphic phantom. Vials containing radiolabeled 18F-fluorodeoxyglucose were placed within the physical phantom thorax as biopsy targets. We measured the average distance between target center and the simulated biopsy location among multiple trials to evaluate the biopsy localization accuracy. The computer simulation results showed that the RASP method generated PET images with a significantly reduced noise of 0.10 ± 0.01 standardized uptake value (SUV) as compared to an end-of-expiration image noise of 0.34 ± 0.04 SUV. The respiratory motion increased the apparent liver lesion size from 5.4 ± 1.1 to 35.3 ± 3.0cc. The RASP algorithm reduced this to 15.7 ± 3.7cc. The distances between the centroids for the static image lesion and two moving lesions in the liver and lung, when reconstructed with the RASP algorithm, were 0.83 ± 0.72mm and 0.42 ± 0.72mm. For the ungated imaging, these values increased to 3.48 ± 1.45mm and 2.5 ± 0.12mm, respectively. For the ungated imaging, this increased to 1.99 ± 1.72mm. In addition, the lesion activity estimation (e.g., SUV) was accurate and constant for images reconstructed using the RASP algorithm, whereas large activity bias and variations (± 50%) were observed for lesions in the ungated images. The physical phantom studies demonstrated a biopsy needle localization error of 2.9 ± 0.9mm from CT. Combined with the localization errors due to respiration for the PET images from simulations, the overall estimated lesion localization error would be 3.08mm for PET-guided biopsies images using RASP and 3.64mm when using ungated PET images. In other words, RASP reduced the localization error by approximately 0.6mm. The combined error analysis showed that replacing the standard end-of-expiration images with the proposed RASP method in PET/CT-guided biopsy workflow yields comparable lesion localization accuracy and reduced image noise. The RASP method can produce PET images with reduced noise, attenuation artifacts and respiratory motion, resulting in more accurate lesion localization. Testing the PET/CT-guided biopsy workflow using computer simulation and physical phantoms with respiratory motion, we demonstrated that guided biopsy procedure with the RASP method can benefit from improved PET image quality due to noise reduction, without compromising the accuracy of lesion localization.

Evaluation of Direct Transfer to Angiography Suite vs. Computed Tomography Suite in Endovascular Treatment: Randomized Clinical Trial (ANGIOCAT)

Evaluation of Direct Transfer to Angiography Suite vs. Computed Tomography Suite in Endovascular Treatment: Randomized Clinical Trial (ANGIOCAT)

Image-guided pulmonary metastasectomy in the hybrid operating room

Surgical radicality is the main prognostic factor in patients who have undergone pulmonary metastasectomy, despite potential differences in underlying primary cancer biology. Current localization techniques place fiducial markers into the lung parenchyma to facilitate detection and guide resection of pulmonary nodules during minimally invasive thoracoscopic surgery. Markers include metal, dye, radiopaque agents, fluorescent contrast, and radiolabeled agents. Traditional marker-guided pulmonary resection comprises a two-stage workflow: (I) preoperative computed tomography (CT)-guided transthoracic implantation of a fiducial marker in the interventional CT suite followed by (II) patient transfer to the operation room for surgical removal. However, the patient is at risk for procedural adverse effects or dislodgement of the marker during the interval period between localization completion and surgery start. The development of a hybrid operating room allows for a one-stage approach to localization, as well as the integration of new imaging modalities and localization methods to pulmonary metastasectomy. In this review, we will explore several current and novel technologies in development relevant for image-guided pulmonary metastasectomy, informed by studies in the setting of hybrid operating room as well as our own experience with the Guided Therapeutics operating room at Toronto General Hospital.

Clinical Utility of Routine Chest X-Rays During the Initial Stabilization of Trauma Patients.

The Advanced Trauma Life Support (ATLS) course encourages the use of chest x-ray (CXR) to identify injuries that may change clinical management during the initial stage of trauma resuscitations. Several studies have failed to show benefit for the routine use of CXR without a clinical indication, however. We sought to validate these findings by determining the incidence of clinically significant findings discovered on a portable single-view CXR during the initial stabilization of trauma patients at a Level 1 trauma center. Using our electronic medical record system, we searched for all of the patients who were brought in as a trauma activation that had a portable single-view CXR performed in the emergency department. We used a selected sampling of available subjects for inclusion into the study. We reviewed the staff radiologist reports for positive findings and reviewed the physician and nursing flow sheets for procedural interventions occurring after the CXR was performed but before leaving the resuscitation area. Subjects who were transferred from another facility, had a thoracic procedure performed before CXR or underwent computed tomography before CXRs were excluded. From 2011 through 2012, we found 2101 subjects who had a portable CXR performed in the emergency department. We reviewed the first 400 subjects' records, with 33 (8.3%) subjects having positive findings on CXR. Of those 33, 8 met inclusion criteria and the remainder met exclusion criteria. The most common findings were pneumothorax (n = 4), clavicle fracture (n = 3), and rib fracture (n = 2). No subjects received a procedural intervention before leaving the resuscitation bay to be transported to the operating room or the computed tomography suite. We observed a low incidence of abnormal findings on portable CXR during the initial stabilization of trauma patients, none of whom received an immediate procedural intervention. This dataset supports previously published reports that suggest that a more targeted approach to CXR use may reduce resource utilization.

Polhemus EM tracked Micro Sensor for CT-guided interventions.

Electromagnetic (EM) tracking is a key technology in image-guided therapy. A new EM Micro Sensor was presented by Polhemus Inc.; it is the first to enable localization of medical instruments through their trackers. Different field generators (FGs) are available by Polhemus, one being almost as small as a sugar cube. As accuracy and robustness of tracking are known challenges to using EM trackers in clinical environments, the goal of this study was a standardized assessment of the Micro Sensor in both a laboratory (lab) and a computed tomography (CT) environment. The Micro Sensor was assessed by means of Hummel etal.'s standardized protocol; it was assessed in conjunction with a Polhemus Liberty tracker and three FGs - with edge lengths of 1 (TX1), 2 (TX2), and 4 (TX4) inches. Precision as well as positional and rotational accuracy were determined in a lab and a CT suite. Distortions by four different metallic cylinders and tracking of two typical medical instruments - a hypodermic needle and a flexible endoscope - were also tested. A jitter of 0.02mm or less was found for all FGs in the different environments, except for the TX2 FG for which no valid data could be obtained in the CT. Errors of 5cm distance measurements were 0.6mm or less for all FGs in the lab. While the distance errors of the TX1 FG were only slightly increased up to 1.6mm in the CT, those of the TX4 FG were found to be up to around 10% of the measured distance (5.4mm on average). The mean orientation error was found to be 0.9° /0.5° /0.1° for the TX4/TX2/TX1 FG in the lab. In the CT environment, rotation errors were in the same range: less than 1.2° /0.1° for the TX4/TX1 FG. Deviation under the presence of metallic cylinders stayed below 1mm in most cases. Precision and orientational accuracy do not seem to be affected by instrument tracking and stayed in the same range as for the other measurements whereas distance errors were slightly increased up to 1.7mm. This study shows that accurate tracking of medical instruments is possible with the new Micro Sensor; it demonstrated a jitter of 0.01mm or less, position errors below 2mm, and rotation errors of less than 0.3° . As with other EM trackers, errors increase when large tracking volumes with ranges of up to 50cm are required in clinical environments. For smaller tracking volumes with ranges of up to 15cm, a high accuracy and robustness was found. This is interesting especially for the TX1 FG which can easily be placed in close vicinity to the region of interest.