Improved detection of metastases on magnetic resonance images by digital tissue recognition: validation using VX-2 tumor in the rabbit

PURPOSE: To evaluate the ability of a prototype digital tissue recognition (DTR) system to improve the accuracy of detection of metastases on magnetic resonance (MR) images in the rabbit VX-2 tumor model. MATERIALS AND METHODS: Multiple MR imaging (MRI) sequences, including pre-contrast and post-contrast enhanced T1-weighted, T2-weighted, proton-density, and fast short inversion time inversion recovery (FSTIR), were acquired for six rabbits implanted with VX-2 adenocarcinoma. For each rabbit, DTR used the MR intensity characteristics of a known tumor site to highlight other areas suspicious for tumor. Three independent veterinary radiologists with extensive experience in animal MRI interpreted the images for tumor both without and with the results of DTR. The conventional and DTR-assisted interpretations were compared to pathology. RESULTS: Using DTR, the radiologists found an average of 13.2% more true positive sites with a 10.3% reduction in false positives compared to unassisted interpretation. The improvement for the radiologists was statistically significant (McNemar's test, P = 0.0004). The agreement between radiologists using DTR was consistently higher than for their conventional interpretations (kappa statistic). CONCLUSION: Compared with conventional interpretation of MR images, the use of DTR provided a statistically significant improvement in the accuracy of locating more and smaller sites of tumor. This improvement was achieved without the benefit of post-contrast images.     

The effect of restricting the indications for lumbosacral spine radiography in patients with acute back symptoms

A prospective study was performed to evaluate the effect of using a special requisition form on the utilization of lumbosacral spine radiography for patients presenting in the emergency room with acute lower back complaints. Over a 1-year period, emergency room house officers were encouraged to complete a special form that listed only three acceptable indications for lumbosacral spine radiographs: history of trauma, evidence of focal neurologic abnormality, and "other." Neurologic abnormalities included hypesthesia, hyperesthesia or anesthesia of lumbar or sacral dermatomes, weakness or hyporeflexia of the lower extremities, and bladder or bowel incontinence. If the indication "other" was chosen, radiographs were done only if the form contained both a one- to two-sentence history and the signed approval of a supervising attending physician. The number and results of lumbosacral spine examinations were compared with those from the previous year, which served as a control. In the control year 1443 examinations were performed, and in the experimental year only 759 were done (a decrease of 47%). The percentage of patients with vertebral fractures increased from 5.1% to 5.8% in the experimental year if only the detection of new fractures was considered positive, and from 9.1% to 13.4% if the detection of fractures of all ages was regarded as significant. The use of the special requisition form appears to be a simple and effective means of reducing unnecessary lumbosacral radiography in the emergency room setting.     

A Survey of Emergency Physician-performed Ultrasound: Implications for Academic Radiology Departments

A survey of academic radiology departments shows that the prevalence of emergency room physician-performed ultrasound examinations is high and that providing a 24/7 attending radiology service leads to no significant reduction in physician activity.     

The role of face-to-face consultation in emergency radiology

To assess the impact of face-to-face exchange of clinical information between the radiologist and the emergency physician, a study was made of all plain films and computed tomograms (CTs) ordered in the Ohio State University Emergency Department between 11 am and 11 pm over a 4-week period. For each case, interpretations at three different times were recorded: (1) initial interpretation upon reception of the images, (2) interpretation after face-to-face discussion of clinical information with the emergency resident or attending physician, and (3) final interpretation after conferring with the attending radiologist. If any of the three interpretations differed in a given case, the case was flagged for review by a third attending radiologist to determine the clinical significance of the discrepancy. Cases which deviated from the standard model as described were excluded from the study. In total, 519 cases were ordered during the study period. Of which 231 (44.5 %) occurred in the standard order as described in the Methods section. Of these 231 cases, changes in diagnosis were observed in 31 (13 %) cases. In 12 (5.2 %) cases, the changes were judged to be clinically significant. In 19 (6 %) cases, the changes were judged to be clinically insignificant. The remaining 288 (55.5 %) cases diverged from the standard model described in our Methods section and were not included in our study. Of these, 93/519 (18 %) cases had only one interpretation because the resident radiologist, the emergency physician (resident and/or attending), and the attending radiologist were present for a single, simultaneous discussion. 77 (15 %) cases, there were only two interpretations because the initial interpretation occurred in the presence of both the resident radiologist and the emergency physician. In 69 (13 %) cases, there were two interpretations because the initial interpretation occurred in the presence of both the resident radiologist and the emergency physician. In 49 (9 %) cases, no face-to-face exchange between the resident radiologist and the emergency physician was recorded. Our data suggest that teleradiology's lack of face-to-face communication between the radiologist and the emergency physician may have an impact on the radiologic diagnosis, but only infrequently. Information contained in the images and the limited clinical history on the consult sheet appear to be sufficient for most purposes of radiologic interpretation.     

Teleradiology in the emergency room.

Many emergency rooms do not offer full-time coverage by a radiologist. Teleradiology can enable a radiologist to offer services to a number of emergency rooms. This allows more timely interpretation of emergency room studies and improved patient care. In our clinical trial, we found several problem areas and developed ways to improve our diagnostic accuracy. Since the resolution of transmitted images is less than that of film, a review of the original films at some later time is needed.     

Evaluation of a 16-MDCT scanner in an emergency department: initial clinical experience and workflow analysis

OBJECTIVE: MDCT is especially suited for emergency purposes because it allows rapid high-resolution scans of large areas, fast high-quality reformatting in every orientation, and 3D illustration of the data set. In a prospective study, we evaluated the reliability and workflow of a dedicated emergency department 16-MDCT scanner in the management of patients presenting to the emergency department. SUBJECTS AND METHODS: The use of a 16-MDCT scanner for 503 patients in the emergency department of a university clinic was evaluated. For reasons of workflow analysis, seven precise time intervals were recorded during the emergency examinations. A new setting for repositioning multiple-trauma patients after imaging of the head and neck from the head-first position to the feet-first position was introduced. RESULTS: Six (1.2%) of the 503 patients were excluded because of technical malfunction or patient noncompliance. Image quality in the remaining 497 cases, including CT angiography and CT of multiple-trauma patients, was outstanding. Positioning of the patients took from 3 to 13 min depending on the body region examined, representing 33-67% of the mean room time, which ranged from 8 to 21 min. In multiple-trauma patients, the initial positioning took a mean of 6 min and repositioning took 8 min, representing 19% and 26% of total room time, respectively. CONCLUSION: The use of a dedicated 16-MDCT scanner in the emergency department resulted in short examination times even for examinations of multiple body regions under emergency conditions. The introduced setting-repositioning of multiple-trauma patients-allowed high image quality to be maintained. The trade-off in multiple-trauma patients was prolonged room time because of patient repositioning.     

Magnetic resonance image examinations in emergency medical care

There is a growing consensus in terms of the need for effective use of magnetic resonance imaging (MRI) diagnostic devices in emergency medical care. However, a thorough assessment of risk management in emergency medical care is required because of the high magnetic field in the MRI room. To understand the conditions required for the execution of emergency MRI examinations in individual medical facilities, and to prepare guidelines for emergency MRI examinations, we carried out a questionnaire survey concerning emergency MRI examinations. We obtained responses from 71% of 230 medical facilities and used this information in considering a system of emergency MRI examinations. Moreover, some difficulties were experienced in half of the facilities where emergency MRI examinations had been enacted, the main cause of which was the medics. Based on the results of the questionnaire, guidelines are necessary to maintain an urgent system for MRI examinations. Moreover, we were able to comprehend the current state of emergency MRI examinations in other medical facilities through this investigation, and we are preparing a system for the implementation of emergency MRI examinations.     

新型冠状病毒肺炎患者影像学检查防控措施

目的探讨如何确立一套防控措施,适用于新型冠状病毒肺炎(coronavirus disease 2019,COVID-19)疑似患者和确诊患者的影像学检查。方法启动应急预案,在隔离病房放置一台移动DR摄影机,给COVID-19患者进行胸部X线摄影,来初步评估治疗效果;指定专用CT检查室,关闭通风系统,划分三区(清洁区、半污染区和污染区),开辟医患专用通道。结果目前我院放射科已经进行了468例次床旁胸部X线摄影检查,270例次胸部CT检查,无1例院内交叉感染事件发生。结论建立一个适用COVID-19患者影像学检查的防控措施,可避免医务人员感染和院内感染。     

Teleradiology Uppsala-Sydney for nighttime emergencies: preliminary experience

BACKGROUND: The development of digital imaging systems for radiology in combination with the possibility to transfer large quantities of data over the Internet has increased the interest in teleradiology. Transferring nighttime examinations to an evaluation center in a daytime zone may provide improved patient security, better working hours for radiologists, and reduced costs for emergency radiological services. PURPOSE: To evaluate the time required for transferring radiological information from Uppsala (Sweden) to Sydney (Australia). MATERIAL AND METHODS: A radiologist in Sydney reported on radiological examinations performed in Uppsala. The time required for downloading 75 examinations and returning 24 reports was registered. RESULTS: Downloading was completed in <60 min for all conventional radiological examinations, but only 44% of computed tomography (CT) examinations with >65 images. Reports were completed in <10 min. Turnaround time was directly related to the time required for downloading the images. The Sydney report was available in Uppsala within 30 min of the in-house report in 79% of examinations. CONCLUSION: The main challenge for emergency teleradiology is the time required for downloading large volumes of data over the Internet.     

Teleradiography for diagnosis in emergency care. A clinical experience]

This work was aimed at evaluating the role of teleradiology in a diagnostic emergency room. Over a 6-month period (September 1991-February 1992), 2,000 films made in the emergency room were transmitted to a resident radiologist 1 kilometer away: each examination included patient's data (sex, age, site of trauma, etc.) which were sent by the admitting physician. A teleradiology system (Lumiscan 100 AT&T and Philips) was used. Films were digitized on a 1024 x 1024 x 8-bit image matrix and then transmitted over a dedicated standard phone line to the Department of Radiology. The autograph report was sent by fax to the emergency room. Four radiologists, of varying experience, independently reviewed a sample of 179 digitized radiographs and, 30 days later, the original films on a conventional light-box. The results appear to be encouraging because no significant differences were observed in the performance of any of the radiologists. Good video/films agreement was obtained, together with high sensitivity and specificity. A good result was the relatively small number (0.4% of all examined cases) of false negatives diagnosed on faxed films relative to the actual clinical diagnosis.     

Perimeter encoding for teleradiology

Perimeter encoding is a technique of data compression that is done simply by outlining the area of interest on an examination. In a sample of 92 emergency room examinations (excluding chest, abdomen, and pelvic exams), 304 films were interpreted by a resident radiologist who indicated the area of interest by marking four corners of a rectangle. The adequacy of the area of interest was determined by a staff osteoradiologist during subsequent review of the films. The amount of data reduction was measured by determining the ratio of the area of interest inside a rectangle to the area of the film (compression ratio). The overall average compression ratio was 3 to 1. This preliminary study suggests that further evaluation of perimeter encoding is warranted.     

Diagnostic performance of teleradiology in cervical spine fracture detection.

This study was done to assess the diagnostic accuracy of high-resolution (5 lp/mm) teleradiology for detecting cervical spine fractures. Single radiographs from 25 patients with and 25 patients without cervical spine fractures were transmitted between two units of our teleradiology system (Dupont DTR 2000) located 5 miles apart. Each image was examined by four readers. Fracture detection accuracy was assessed by generating receiver operating characteristic (ROC) curves and comparing the areas under each reader's curves for original and transmitted images. Two readers had statistically significant better fracture detection using nontransmitted images, whereas two had no significant differences in accuracy. The authors conclude that high resolution in and of itself is not adequate for fracture detection, and that issues concerning image contrast manipulation also will have to be addressed before teleradiology systems can be used for clinical cervical spine fracture screening.     

Prospective evaluation of handheld ultrasound in the diagnosis of blunt abdominal trauma

OBJECTIVES: To evaluate the Sonosite 180 handheld ultrasound in the diagnosis of haemoperitoneum in blunt abdominal trauma. METHODS: Trauma ultrasound using the Focused Assessment with Sonar for Trauma (FAST) technique was performed using the Sonosite 180 handheld ultrasound during the primary survey of adult patients triaged to the resuscitation room with multiple trauma or suspected abdominal injury. The ultrasound findings were compared against the investigation of choice of the attending surgeon/accident & emergency physician--CT, DPL, laparotomy or clinical observation. RESULTS: 50 patients who had sustained blunt abdominal trauma were evaluated using FAST. Satisfactory images were obtained in 96%. There were 5 true positive scans confirmed by CT, DPL or laparotomy. There were no false negative or false investigations. The sensitivity and specificity of handheld FAST was 100%. CONCLUSIONS: Handheld ultrasound using the Sonosite 180 system can be successfully used by appropriately trained doctors as the primary investigation in the acute evaluation of blunt abdominal trauma.     

Incidence of pulmonary emboli on chest computed tomography angiography based upon referral patterns

Pulmonary embolism (PE) is a potentially lethal condition, and the diagnosis of PE can be difficult. The purpose of this study is to evaluate the incidence of PE on chest computed tomography angiography (CTA) studies ordered in the inpatient, outpatient, and emergency department (ED) settings and further segregated based on the adult and pediatric populations, and by the ordering clinician (attending physicians, resident physicians, or physician extenders). A retrospective review of chest CTA examinations performed between July 1,2009 and June 30, 2010 was performed. Of 5848 adult CTA studies, PE was diagnosed in 594 (10.1 %). Of these positive studies, 315 (53 %) were inpatient, 234 (39.4 %) were ED patients, and 45 (7.6 %) were outpatient. Four hundred sixty-four of 4445 (10.4 %) CTA examinations ordered by attending physicians were positive for PE. Seventy-four of the 801 (9.2 %) CTA examinations ordered by resident physicians were positive for PE. Fifty-six of the 608 CTA examinations ordered by physician extenders were positive for PE. Thirty-three pediatric CTA studies for PE met criteria and none of them indicated PE. There is no significant difference in the incidence of PE in chest CTA based on setting or ordering clinician.     

Three-dimensional high-resolution dynamic contrast-enhanced MR angiography of the pelvis and lower extremities with use of a phased array coil and subtraction: Diagnostic accuracy

In this study, our purpose was to compare the high-resolution contrast-material-enhanced three-dimensional subtraction MR angiography with conventional angiography for occlusive disease in the pelvic and lower extremity arteries. A three-dimensional fast-imaging with steady precession (FISP) sequence with a 256 × 512 matrix was obtained on 1.5T MR unit using a phased array coil. Twenty patients with arteriosclerotic obstructive disease underwent subtraction dynamic contrast-enhanced MR angiography. In 15 patients, three regions (pelvis, upper knee, and lower knee) were sequentially obtained after repeated injection of gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA). In the other five patients, one region was imaged (total of 50 examinations); a maximum-intensity projection (MIP) algorithm was used for subtracted images. All patients also underwent conventional angiography. Angiographic images were divided into several anatomical segments. Three blinded radiologists independently graded a total of 50 anatomic segments with stenotic or obstructive diseases and 90 segments without disease. Subtracted images allowed resolution of small branch vessels in all examinations, although misregistration was seen in eight examinations of five patients. All arteries larger than 1 mm in diameter were visualized on subtracted images. For detection of significant stenosis (>50%), MR angiography had 96% sensitivity and 83% specificity. The correlation coefficient of degree of agreement between MR angiography and conventional angiography was .92. Stenotic vessels tended to be overestimated. We conclude that high-resolution dynamic contrast-enhanced three-dimensional MR angiography is capable of depicting small vessel anatomy of the pelvis and lower extremities. Sequential MR angiography of different regions was feasible by repeated injection of Gd-DTPA and subtraction. This technique is highly sensitive in detecting lesions, but stenosis tended to be overestimated.     

Influence of medicolegal factors in the use of cervical spine and head computed tomographic examinations in an emergency setting

Estimates suggest that defensive medicine, including radiologic studies, costs Americans more than $21 billion annually. As a result of our prior evaluation of 13,228 emergency department patients, we already knew that cervical spine and head computed tomographic examinations were the third and fourth most commonly ordered studies in our emergency department. The emergency medicine, obstetrics/gynecology, surgery, and internal medicine physicians at The Ohio State University agreed to cooperate in a study to determine the factors that influence the decision to order these examinations. Overall, 26 (28%) of the physicians surveyed had personal experience in a medical malpractice lawsuit. Attending physicians in all groups were more concerned about potential medicolegal consequences, compared to residents and fellows (P=0.055) when ordering cervical spine examinations. This coincides with the finding that attending physicians were more likely to have been sued (P<0.001). Emergency medicine physicians were more likely to order one of these examinations if the patient had demanded or requested it (P<0.001) and were more likely to weight physical examination findings more heavily (P=0.007) when compared to other physician groups. Finally, all physician groups combined suggested that approximately 33% of all cervical spine and 39% of all head computed tomographic examinations could be avoided if there were no worries about medicolegal consequences.     

Evaluation of a CT triage protocol for mass casualty incidents: results from two large-scale exercises

The purpose of this study was to evaluate the feasibility, stability, and reproducibility of a dedicated CT protocol for the triage of patients in two separate large-scale exercises that simulated a mass casualty incident (MCI). In both exercises, a bomb explosion at the local soccer stadium that had caused about 100 casualties was simulated. Seven casualties who were rated “critical” by on-site field triage were admitted to the emergency department and underwent whole-body CT. The CT workflow was simulated with phantoms. The history of the casualties was matched to existing CT examinations that were used for evaluation of image reading under MCI conditions. The times needed for transfer and preparation of patients, examination, image reconstruction, total time in the CT examination room, image transfer to PACS, and image reading were recorded, and mean capacities were calculated and compared using the Mann–Whitney U test. We found no significant time differences in transfer and preparation of patients, duration of CT data acquisition, image reconstruction, total time in the CT room, and reading of the images. The calculated capacities per hour were 9.4 vs. 9.8 for examinations completed, and 8.2 vs. 7.2 for reports completed. In conclusion, CT triage is feasible and produced constant results with this dedicated and fast protocol.     

Quantitative evaluation of measurement accuracy for three-dimensional angiography system using various phantoms

PURPOSE: The purpose of this study was to evaluate the spatial resolution and accuracy of three-dimensional (3D) distance measurements performed with 3D angiography using various phantoms. MATERIALS AND METHODS: With a 3D angiography system, digital images with a 512 x 512 matrix were obtained with the C-arm sweep, which rotates at a speed of 30 degrees/second. A 3D comb phantom was designed to assess spatial resolution and artifacts at 3D angiography and consisted of six combs with different pitches: 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, and 1.0 mm. Frame rate, field of view (FOV) size, reconstruction matrix, and direction of the phantom were changed. In order to investigate the accuracy of 3D distance measurements, aneurysm phantoms and stenosis phantoms were used. Aneurysm phantoms simulated intracranial saccular aneurysms and parent arteries; 2-mm- or 4-mm-inner-diameter cylinder and five different spheres (diameter: 10, 7, 5, 3, 2 mm) were used. Stenosis phantoms were designed to simulate intracranial steno-occlusive diseases; the nonpulsatile phantoms were made of four cylinders (diameter: 3.0, 3.6, 4.0, 5.0 mm) that had areas of 50% and 75% stenosis. The dimensions of the spheres and cylinders were measured on magnified multiplanar reconstruction (MPR) images. RESULTS: The pitch of the 0.5 mm comb phantom was identified clearly on 3D images reconstructed with a frame rate of 30 frame/sec and 512(3) reconstruction mode. In any reconstruction matrixes and any angles of the phantom, the resolution and artifacts worsened when frame rates were decreased. With regard to the angle of the phantom to the axis of rotational angiography, spatial resolution and artifacts worsened with increase in angle. Spatial resolution and artifacts were better with a FOV of 7 x 7 inch than with one of 9 x 9 inch. All spheres on the aneurysm phantom were clearly demonstrated at any angle; measurement error of sphere size was 0.3 mm or less for 512(3) reconstruction. In 512(3) reconstruction, the error of percent stenosis was 3% or less except for a cylinder diameter of 3.0 mm and 5% for a cylinder diameter of 3.0 mm. CONCLUSION: Spatial resolution of the reconstructed 3D images in this system was 0.5 mm or less. Measurement error of sphere size was 0.3 mm or less when 512(3) reconstruction was used. When using proper imaging parameters and postprocessing methods, measurements of aneurysm size and percent stenosis on the reconstructed 3D angiograms were substantially reliable.     

Teleradiology/PACS usage: A survey of the American Society of Emergency Radiology Membership

The purpose of this study was to assess the use of teleradiology/picture archiving and communications (PACS) systems for emergency patients by members of the American Society of Emergency Radiology (ASER). Results were tabulated from a survey mailed to ASER members in February 1997. The listed percentages are based on the total number of answers to a particular question. ASER members representing 76 medical centers responded to the survey. Forty-five of the centers (59%) were level I trauma centers, and 17 (22%) were level II trauma centers. Forty-five centers (59%) had teleradiology/PACS systems. Another 13 (19%) planned to acquire teleradiology/PACS equipment within a year. In 32 (74%) of the centers with teleradiology/PACS systems, patients with emergency conditions accounted for more than half of the total teleradiology/PACS volume. Teleradiology/PACS systems were utilized for head computed tomographic (CT) examinations in 35 centers (85%), body CT in 34 (81%), ultrasound in 28 (67%), plain radiography in 24 (57%), and magnetic resonance imaging (MRI) in 18 (44%). Final interpretations were made primarily from original films in 23 centers (56%), monitor image in 11 (27%), or both in 7 (17%). The most common uses for the teleradiology/PACS equipment were interpretations of examinations performed at another site within the same center in 24 centers (56%), wet readings from home in 18 (42%), interpretation of examinations from other centers in 25 (59%), and off-hours coverage of practice at another site in 18 (42%). Eleven centers (33%) reported rare or occasional technical limitations to examination interpretation, most commonly relating to loss of resolution or detail on the monitor image, preventing visualization of a finding. Teleradiology/PACS systems have resulted in quicker interpretations in 33 centers (82.5%) and reduced lost film count in 12 (29%). Seventy-eight percent of ASER members’ centers are expected to have teleradiology/PACS equipment within 1 year. Emergency conditions, off-hours coverage, and remote coverage of sites within the centers were the most frequent uses.     

An assessment of different healthcare professionals’ attitudes towards radiographers’ reporting A&E films

Purpose: To assess whether different professionals in a district hospital found acceptable the reporting of accident and emergency (A&E) plain films for selected body areas by two specifically trained radiographers.Methods: A self-answer questionnaire using the Likert scale was used to measure the attitude of different professionals at the hospital towards the introduction of radiographers reporting. An open-ended section investigated how this may have freed time for radiologists to perform other tasks, the effect on the radiographers’ workload and the possibility of extending their reporting role.Results: With the exception of one radiologist, who was uncertain, the different professionals agreed that radiographers reporting A&E films for selected body areas was acceptable and a success. However, reporting has reduced these radiographers’ involvement in conventional radiography and speciality areas like angiography or computed tomography. The consensus between radiologists was that it has done little to alleviate their reporting workload. Furthermore, in contrast with the two radiographers who agreed that their reporting role should be extended to include all A&E examinations, other professionals disagreed or were uncertain. It was also suggested that not reporting any A&E films could de-skill radiologists.Conclusions: The reporting of A&E films for selected body areas by specifically trained radiographers was found to be acceptable by all professional groups. However, extending the radiographers reporting role was considered more contentious as it could be at the expense of other skills. The radiologists reporting skills could also be diminished with little benefit to other areas of their work.