Management of Acute Contrast Reactions-Understanding Radiologists' Preparedness and the Efficacy of Simulation-Based Training in Canada.

PURPOSE: Acute radiologic emergencies, primarily severe contrast reactions, are rare but life-threatening events. Given a generalized paucity of formalized or mandated training, studies have shown that radiologists and trainees perform poorly when acutely managing such events. Moreover, skill base, knowledge, and comfort levels precipitously decline over time given the infrequent occurrence of these events during one's daily practice. The primary aim of this study was to assess radiologists' preparedness for managing acute radiologic emergencies and to determine the efficacy of a high-fidelity simulation based training model in an effort to provide a rationale for similar programs to be implemented on a provincial or national level. METHODS: This was a prospective, observational study of radiology residents and attending radiologists throughout the province who were recruited to attend a full-day simulation-based course presenting various cases of acute radiologic emergencies. Participant demographics were collected at the time of commencement of the workshop. Course materials were disseminated 4 weeks prior to the workshop, and a 17-question knowledge quiz was administered before and after the workshop. Likert-type questionnaires were also distributed to survey comfort levels and equipment familiarity. The knowledge quiz and questionnaire were redistributed at 3- and 6-month intervals for acquisition of follow-up data. RESULTS: A total of 14 attending radiologists and 7 residents attended the workshop, with all participants completing the preworkshop questionnaire and 90.5% (19 of 21) completing the post-workshop questionnaire. Participants' principle locations of practice were as follows: academic institutions (50%), community hospitals (36.9%), and private clinics (13.1%). A significant increase in knowledge was demonstrated, with average scores of 10 out of 17 (59%) and 14.5 out of 17 (85%) (P < .001) before and after the workshop, respectively. A significant increase in participants' comfort levels in recognizing acute anaphylactic reactions (3.5; 4.7, P < .001), commencing initial management for acute radiologic emergencies (3.3; 5.0, P < .001), and administering the correct dose for anaphylactic reactions (2.5; 4.8, P < .001) was also demonstrated. Moreover, participants became increasingly familiar with the contents and equipment found within contrast reaction kits (2.8; 3.8, P < .01). Repeat evaluations at 3 and 6 months found an average knowledge test score of 13.8 out of 17 (81%) and 10.8 out of 17 (64%), respectively. Comfort levels were also reassessed in recognizing acute anaphylactic reactions (4.5; 4.1), commencing initial management (4.0; 3.9) and administering the correct dose of medication (4.0; 3.7) at 3- and 6-month intervals. CONCLUSIONS: Acute radiologic emergencies are rare but life-threatening events that require rapid diagnosis and treatment to mitigate associated morbidity and mortality. Simulation-based workshops are a highly efficacious training model to increase knowledge, comfort levels, and equipment familiarity for radiologists and trainees alike; however, retraining at regular intervals is required.

Uterine arteriovenous malformations: from diagnosis to treatment.

OBJECTIVE: The purpose of this study was to describe the sonographic features of uterine arteriovenous malformations (AVMs) and to describe the role and clinical outcome after transcatheter arterial embolization of symptomatic uterine AVMs. METHODS: In our institution, over a 4-year period, symptomatic uterine AVMs were diagnosed in 21 women. Endovaginal sonography with gray scale, color, and spectral Doppler imaging was performed on all patients. Fourteen patients required therapeutic angiography/embolization to control bleeding. These 14 patients had follow-up endovaginal sonography 24 hours after the procedure. RESULTS: The sonographic gray scale findings of uterine AVMs were nonspecific. The most common finding was subtle myometrial heterogeneity (n = 14), whereas other patients had small anechoic spaces in the myometrium (n = 7). Color Doppler sonography showed a tangle of vessels with multidirectional high-velocity flow that produced a "color mosaic" pattern. Spectral Doppler analysis showed arteriovenous shunting with high-velocity, low-resistance flow. Fourteen patients required transcatheter arterial embolization to control bleeding. Thirteen of 14 patients had no sonographic evidence of a residual AVM 24 hours after the procedure. One of 14 patients had a residual AVM requiring additional embolization. One patient had recurrent bleeding at 4 months and required further embolization. The remaining 7 patients were treated conservatively. CONCLUSIONS: Endovaginal sonography is the imaging modality of choice in patients with abnormal uterine bleeding. Routine use of color and spectral Doppler sonography allows one to confidently make the correct diagnosis. Transcatheter arterial embolization is an excellent treatment option. Endovaginal sonography should be used to monitor postembolization outcomes.

Sonographic examination of the carotid arteries.

Ultrasonography (US) of the carotid arteries is a common imaging study performed for diagnosis of carotid artery disease. In the United States, carotid US may be the only diagnostic imaging modality performed before carotid endarterectomy. Therefore, the information obtained with carotid US must be reliable and reproducible. Technical parameters that can affect the accuracy of carotid US results include the Doppler angle, sample volume box, color Doppler sampling window, color velocity scale, and color gain. Important factors in diagnosis of atherosclerotic disease of the extracranial carotid arteries are the intima-media thickness, plaque morphology, criteria for grading stenosis, limiting factors such as the presence of dissection or cardiac abnormalities, distinction between near occlusion and total occlusion, and the presence of a subclavian steal. Challenges to the consistency of carotid US results may include lack of a standard protocol, poor Doppler technique, inexperience in interpretation of hemodynamic changes reflected in the Doppler waveform, artifacts, and physical challenges. Hindrances in the classification of problematic carotid artery stenoses may be overcome by following a standard protocol and optimizing scanning techniques and Doppler settings.

Carotid artery stenosis in asymptomatic patients who have received unilateral head-and-neck irradiation.

PURPOSE: To determine the prevalence of carotid artery stenosis in patients who have received ipsilateral head-and-neck radiotherapy and have no symptoms of cerebrovascular disease. METHODS AND MATERIALS: Forty patients underwent ultrasound and computed tomography angiography of their carotid arteries. The vessels on the irradiated side were compared with those on the unirradiated side in a matched-pair analysis with regard to any stenosis, stenosis > or =60% in the internal carotid artery/carotid bulb, intima medial thickness (IMT), and grade of wall abnormalities. History, physical, and fasting blood levels were taken to detect risk factors for carotid disease. RESULTS: Fourteen irradiated carotid trees bore one or more stenosis vs. five in the unirradiated ones (p = 0.03). There were six bulb/internal carotid artery stenoses > or =60% in the irradiated carotids vs. one in the unirradiated (OR 6:1, p = 0.13). IMT and grade of vessel wall abnormality were higher in the irradiated carotids, but only at doses > or =50 Gy, and only at measurement points that lay within the radiation portals. CONCLUSION: Radiation appears to cause carotid artery stenosis. There may be a dose threshold for carotid wall changes, which has relevance for radiotherapy in several tumor sites.

Emergency radiology in Canada: a national survey.

OBJECTIVE: To document the existing radiology services available to emergency physicians in hospitals across Canada and to preview future trends and needs. METHODS: Questionnaires (n = 130) regarding the type, availability and satisfaction with radiology services were distributed to radiologists and emergency physicians at 65 hospitals across Canada. RESULTS: Fifty-three (41%) questionnaires were returned, and 45 (35%) completed questionnaires from 35 hospitals were used for analysis (24 from radiologists and 21 from emergency physicians). Plain radiographs were available in all hospitals at all times. Ultrasonography, intravenous pyleograms and computed tomography (CT) were available in all departments during normal working hours; after hours, CT was unavailable in 1 hospital and ultrasonography was unavailable in 2. Focused assessment with sonography for trauma (FAST) was routinely performed for blunt abdominal trauma in 6 centres, and 10 centres had teleradiology services. Regarding the quality of emergency service, 7 of 45 responded "poor," 4 "average," 14 "good," and 17 of 45 rated service "excellent." Interestingly, most radiologists answered "good" or "excellent," and most of the "poor" responses came from emergency physicians. Regarding staff coverage after 5 pm, 34 hospitals provided CT services, 20 had ultrasonography staff available, and there was radiology nursing coverage in 14 hospitals. Clinical details on requisitions were generally rated "adequate" or "poor." Although most radiograph reports were available within 48 hours, some took longer. Hot-seat reporting was available in 11 centres. During normal working hours, radiologists were the first to read films in 5 of 35 hospitals. After hours, emergency physicians were the first to read films in all hospitals, but only 14 hospitals indicated they were "formally" trained to do so. CONCLUSION: This survey documents the strengths and weaknesses of the radiology services available to emergency physicians. The perceptions of emergency physicians and radiologists of the adequacy those services differ significantly.