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Thứ Sáu, ngày 02 tháng 10 năm 2015


J U M 10-2015

Selected Abstracts
1.      Abstract 1 of 6Original Research
Sensitivity and Specificity of the Toe-Brachial Index for Detecting Peripheral Arterial Disease
Initial Findings
Objectives—The toe-brachial index (TBI) is an alternative to the ankle-brachial index (ABI) in screening for peripheral arterial disease (PAD); however, there is limited evidence comparing their diagnostic accuracy. This study compared the diagnostic accuracy of the ABI and TBI in a population at risk of PAD.
Methods—The sensitivity and specificity of the ABI and TBI were determined by color duplex sonography. Receiver operating characteristic (ROC) analysis was performed.
Results—A total of 119 participants were recruited (75 male and 44 female). The sensitivity for PAD was highest for the TBI (71%; ABI, 45%), and the specificity was highest for the ABI (93%; TBI, 78%). Receiver operating characteristic analysis indicated that the TBI (ROC area, 0.77; P = .0001) had greater clinical efficacy for diagnosis of PAD than the ABI (ROC area, 0.65; P = .005).
Conclusions—In specific populations, the TBI may have greater clinical efficacy than the ABI for diagnosis of PAD.
o    © 2015 by the American Institute of Ultrasound in Medicine
2.      Abstract 2 of 6Original Research
Using Ultrasound to Enhance Medical Students’ Femoral Vascular Physical Examination Skills
Objectives—To determine whether the addition of ultrasound to traditional physical examination instruction improves junior medical students’ abilities to locate the femoral pulse.
Methods—Initially, 150 second-year medical students were taught the femoral pulse examination using traditional bedside teaching on standardized patients and online didactic videos. Students were then randomized into 2 groups: group 1 received ultrasound training first and then completed the standardized examination; and group 2 performed the standardized examination first and then received ultrasound training. On the standardized patients, the femoral artery was marked with invisible ink before the sessions using ultrasound. Compared to these markers, students were then evaluated on the accuracy of femoral artery pulse palpation and the estimated location of the femoral vein. All students completed a self-assessment survey after the ultrasound sessions.
Results—Ultrasound training improved the students’ ability to palpate the femoral pulse (P= .02). However, ultrasound did not facilitate correct estimation of the femoral vein’s anatomic location (P = .09). Confidence levels in localizing the femoral artery and vein were equal between groups at baseline, and both increased after the ultrasound sessions.
Conclusions—The addition of ultrasound teaching to traditional physical examination instruction enhanced medical student competency and confidence with the femoral vascular examination. However, understanding of anatomy may require emphasis on precourse didactic material, but further study is required.
o    © 2015 by the American Institute of Ultrasound in Medicine
3.      Abstract 3 of 6Original Research
Ultrasound Integration in Undergraduate Medical Education: Comparison of Ultrasound Proficiency Between Trained and Untrained Medical Students
Objectives—The benefit of formal ultrasound implementation in undergraduate medical education remains unclear. The goal of this study was to evaluate the effectiveness of ultrasound curriculum implementation during year 1 medical student physical examination teaching on the ultrasound proficiency of medical students.
Methods—An ultrasound curriculum was formally implemented at our institution in August 2012 and since then has successfully trained 2 classes of medical students (year 1 and year 2). Year 3 and year 4 medical students did not receive any formal ultrasound training, as the curriculum had not yet been implemented during their preclinical years. With the use of a 22-point ultrasound objective structured clinical examination (US-OSCE), trained medical students were compared to untrained medical students. The US-OSCE tested image acquisition and interpretation of the following systems: ocular, neck, vascular, pulmonary, cardiovascular, and abdominal. Emergency medicine (EM) residents formally trained in bedside ultrasound were also tested with the US-OSCE to provide a reference standard.
Results—There were 174 year 1, 25 year 2, and 19 year 3/year 4 medical students and 30 EM residents tested on the US-OSCE. Ultrasound-trained medical students were compared to untrained medical students, and overall US-OSCE scores ± SD were 91.4% ± 14.0% versus 36.1% ± 21.4% (P < .001), respectively. The EM resident group had an overall score of 99.1% ± 1.8%. The absolute percentage differences were 7.7% between EM resident and ultrasound-trained medical student scores and 63.0% between EM resident and untrained medical student scores (P < .001).
Conclusions—Implementation of an ultrasound curriculum in undergraduate medical education showed a significant increase in trained versus untrained medical student ultrasound capabilities.
o    © 2015 by the American Institute of Ultrasound in Medicine
4.      Abstract 4 of 6Original Research
Internal Carotid Artery Hypoplasia
Role of Color-Coded Carotid Duplex Sonography
Objectives—The purpose of this study was to determine the role of color-coded carotid duplex sonography for diagnosis of internal carotid artery hypoplasia.
Methods—We retrospectively reviewed 25,000 color-coded carotid duplex sonograms in our neurosonographic database to establish more diagnostic criteria for internal carotid artery hypoplasia.
Results—A definitive diagnosis of internal carotid artery hypoplasia was made in 9 patients. Diagnostic findings on color-coded carotid duplex imaging include a long segmental small-caliber lumen (52% diameter) with markedly decreased flow (13% flow volume) in the affected internal carotid artery relative to the contralateral side but without intraluminal lesions. Indirect findings included markedly increased total flow volume (an increase of 133%) in both vertebral arteries, antegrade ipsilateral ophthalmic arterial flow, and a reduced vessel diameter with increased flow resistance in the ipsilateral common carotid artery. Ten patients with distal internal carotid artery dissection showed a similar color-coded duplex pattern, but the reductions in the internal and common carotid artery diameters and increase in collateral flow from the vertebral artery were less prominent than those in hypoplasia. The ipsilateral ophthalmic arterial flow was retrograde in 40% of patients with distal internal carotid artery dissection. In addition, thin-section axial and sagittal computed tomograms of the skull base could show the small diameter of the carotid canal in internal carotid artery hypoplasia and help distinguish hypoplasia from distal internal carotid artery dissection.
Conclusions—Color-coded carotid duplex sonography provides important clues for establishing a diagnosis of internal carotid artery hypoplasia. A hypoplastic carotid canal can be shown by thin-section axial and sagittal skull base computed tomography to confirm the final diagnosis.
o    © 2015 by the American Institute of Ultrasound in Medicine
5.      Abstract 5 of 6Original Research
Transcranial Parenchymal Sonographic Findings in Patients With Cerebral Small Vessel Disease
A Preliminary Study
Objectives—Patients with cerebral small vessel disease often present with various motor, cognitive, and emotional changes, including gait disturbances, parkinsonism, and depression. Substantia nigra hyperechogenicity, brain stem raphe hypoechogenicity, ventricle diameters, and sonographic characteristics of other brain structures on transcranial sonography have been increasingly used as biomarkers in a range of neurologic diseases. We aimed to explore the frequency and clinical correlates of transcranial sonographic findings in symptomatic patients with small vessel disease.
Methods—In a cross-sectional study, neurologic, cognitive, and emotional statuses and transcranial sonographic and magnetic resonance imaging findings were compared between 102 patients with small vessel disease and 45 healthy age- and sex-matched control participants.
Results—Compared to healthy controls, small vessel disease cases had more frequent brain stem raphe hypoechogenicity (55.9% versus 11.1%; P < .0001), substantia nigra hyperechogenicity (30.4% versus 11.1%; P = .022), and enlarged third ventricles (P < .0001). Substantia nigra hyperechogenicity correlated with gait disturbances, extrapyramidal features, and cognitive impairment. Brain stem raphe hypoechogenicity was associated with the diagnosis of depression. Enlargement of the third and lateral ventricles was more frequent in patients with cognitive impairment. Pathologic substantia nigra hyperechogenicity and enlarged ventricles were associated with the severity of cerebral ischemic lesions.
Conclusions—Transcranial sonography shows pathologic findings in a substantial number of patients with small vessel disease, probably reflecting disruption of frontostriatal pathways.
o    © 2015 by the American Institute of Ultrasound in Medicine
6.      Abstract 6 of 6Original Research
Evaluating Didactic Methods for Training Medical Students in the Use of Bedside Ultrasound for Clinical Practice at a Faculty of Medicine in Romania
Objectives—Medical students’ time is limited, so efficiency in medical education is valued. This research project aimed to determine the most effective means to teach bedside ultrasound to medical students in a 1-week training course. We hypothesized that the best method would include a combination of podcasts and hands-on teaching; therefore, there would be a statistically significant difference among the various methods of teaching.
Methods—Medical students were randomly assigned to 3 groups. All groups attended a 50-minute hands-on bedside ultrasound training session. Students in the first group attended a 50-minute live lecture before the hands-on session, whereas students in the second group watched a podcast that covered the same material as the live lecture. Students in the third group served as the control and only attended the hands-on sessions. Five topics were covered during the course: (1) introduction to ultrasound, (2) pulmonary ultrasound, (3) cardiac ultrasound, (4) hepatobiliary ultrasound, and (5) focused assessment with sonography for trauma. Students completed a 20-question pre- and post-training quiz that covered basic ultrasound principles. Students also conducted a focused assessment with sonography for trauma examination for the practical portion of their evaluation.
Results—Students’ pre- to post-training quiz scores increased from 33.6% to 72.6% correct in the lecture group (n = 21; P < .0001), from 40.7% to 75.5% correct in the podcast group (n = 20; P< .0001), and from 37.8% to 70.0% correct in the control group (n = 23; P< .0001). Data analysis of written and practical examination scores showed no significant differences among the groups [F(2,61) = 0.885; P = .418; F(2,60) = 1.739; P = .184, respectively].
Conclusions—These results suggest that all 3 methods are equally effective in teaching novice medical students basic ultrasound knowledge and skills.
o    © 2015 by the American Institute of Ultrasound in Medicine