Contrast Usage Research Articles

488P A retrospective audit on usage of oral water soluble contrast in patients with known advanced cancer

488P A retrospective audit on usage of oral water soluble contrast in patients with known advanced cancer

488P A retrospective audit on usage of oral water soluble contrast in patients with known advanced cancer

488P A retrospective audit on usage of oral water soluble contrast in patients with known advanced cancer

Initial experience with live three-dimensional image overlay for ductal stenting in hypoplastic left heart syndrome.

Precise visualisation of ductal morphology and adjacent vessels is crucial for accurate stent choice and placement during hybrid palliation of hypoplastic left heart syndrome (HLHS). We aimed to describe our initial experience with live three-dimensional reconstruction overlay derived from rotational angiography (RA) for ductal stenting in HLHS. We carried out a retrospective review of ductal stenting in 18 newborns with HLHS, including six patients with 3D reconstruction overlay used to guide the intervention. The median age at the intervention was 20 days (range 13-31 days) and the median weight was 3.25 kg (range 3-4 kg). Eleven RA runs were performed, pre and post stent implantation in five patients and before the intervention in one patient. 3D reconstructions from all RA runs had sufficient image quality to allow stent placement without additional contrast injections. Comparison with 2D angiography-guided ductal stenting showed similar contrast usage, with the 2D angiography patients receiving a higher radiation dose. Three-dimensional rotational angiography provides accurate visualisation of the ductal morphology and nearby structures. Three-dimensional reconstruction overlay with clear landing points enabled precise stent implantation with no additional contrast injections and lower radiation doses than conventional angiography in our patients.

A Hidden Markov Model for 3D Catheter Tip Tracking With 2D X-ray Catheterization Sequence and 3D Rotational Angiography.

In minimal invasive image guided catheterization procedures, physicians require information of the catheter position with respect to the patient's vasculature. However, in fluoroscopic images, visualization of the vasculature requires toxic contrast agent. Static vasculature roadmapping, which can reduce the usage of iodine contrast, is hampered by the breathing motion in abdominal catheterization. In this paper, we propose a method to track the catheter tip inside the patient's 3D vessel tree using intra-operative single-plane 2D X-ray image sequences and a peri-operative 3D rotational angiography (3DRA). The method is based on a hidden Markov model (HMM) where states of the model are the possible positions of the catheter tip inside the 3D vessel tree. The transitions from state to state model the probabilities for the catheter tip to move from one position to another. The HMM is updated following the observation scores, based on the registration between the 2D catheter centerline extracted from the 2D X-ray image, and the 2D projection of 3D vessel tree centerline extracted from the 3DRA. The method is extensively evaluated on simulated and clinical datasets acquired during liver abdominal catheterization. The evaluations show a median 3D tip tracking error of 2.3 mm with optimal settings in simulated data. The registered vessels close to the tip have a median distance error of 4.7 mm with angiographic data and optimal settings. Such accuracy is sufficient to help the physicians with an up-to-date roadmapping. The method tracks in real-time the catheter tip and enables roadmapping during catheterization procedures.

Concomitant Parallel Endografting and Fenestrated Experience in a Regional Aortic Center

Off-label parallel endografting (PE) has been increasingly criticized in favor of on-label custom fenestrated endografts. There remain limited direct comparisons, however, between concurrent patient populations treated by similarly experienced operators. Hence, we seek to evaluate the relative efficacy of the two techniques in treating complex aortic pathology. All patients treated by PE or with Cook Zenith Fenestrated (Zfen) devices from January 2010 to June 2015 were reviewed, excluding those treated for rupture. Patients were all evaluated for open repair as well as for fenestrated devices since its availability at our center in July 2013. Patients predating fenestrated access or not meeting anatomic indications for use criteria and preferring endovascular therapy were treated with PE. A total of 93 patients were treated during the period reviewed, 54 (58.1%) by PE and 39 (41.9%) with Zfen. The two procedures required similar length of surgery (234min PE vs. 239 min Zfen), blood loss (634cc vs. 409cc), and length of stay (median 6days). PE, however, was associated with less fluoroscopy time (52.8 vs. 64.6min) and contrast volume (103.5cc PE vs. 133cc Zfen). At mean 202days follow-up, Zfen has required three reinterventions (two type III endoleaks and one superior mesenteric artery stenosis causing mesenteric ischemia) and there have been zero branch vessels lost. At mean 427days follow-up, PE patients experienced three stent occlusions (one repaired endovascularly) and required eight additional interventions (two type I endoleaks, two type II endoleaks with sac growth, two type III endoleaks, one graft infection, and one aneurysm rupture). Reintervention rates for PE and Zfen were 17.6% and 7.7%, respectively, with branch patency rates of 98% and 100%. PE and fenestrated repair offer similarly high branch patency and technical success. PE performed for juxtarenal aneurysms has similar reintervention rate to fenestrated repair. The two techniques have similar length of stay, operative time, and blood loss, but fenestrated repair is associated with greater fluoroscopy time and contrast usage.

Optical coherence tomography angiography — novel method to access retinal microcirculation in patients with diabetic retinopathy

Introduction. Optical coherence tomography angiography (OCTA) is a novel technique that allows visualization of retinal capillary network without the need for contrast usage. Being easy to perform and non-invasive, it might become significantly competitive to fluoroangiography. Material and methods. The study included 45 patients (90 eyes) with diabetes type 1 and 2 and nonproliferative and proliferative diabetic retinopathy as well as 35 healthy volunteers (70 eyes) as a control group. Beside full ophthalmic examination, all patients underwent OCTA (RTVue XR Avanti; Optovue) examination. Obtained images were used to assess the presence of morphologic changes of the retina characteristic for diabetic retinopathy (capillary density and regularity as well as occurrence of microaneurysms, ischemic areas, intraretinal microvascular abnormalities and neovascularizations). The assessment was carried out on two levels of retinal capillary plexus. Additionally, measurement of foveal avascular zone (FAZ) was performed. The results were compared with those obtained from the control group. Results. All examined eyes in the studied group exhibited one or more anomalies characteristic of diabetic retinopathy as seen on the OCTA scans, both in superficial and deep vascular plexus. In the control group we have detected capillary irregularity (9% in a superficial and 11% in a deep vascular plexus) and capillary rarefication (7% in a superficial and 9% in a deep vascular plexus) and no other anomalies were found. Mean FAZ area measured in superficial vascular plexus was 382 ± 134 square micrometers and was significantly larger (p < 0,001) in comparison to the control group (259 ± 103 square micrometers). Conclusions. Optical coherence tomography angiography is a useful diagnostic tool used to assess vascular changes in the retinal microcirculation in diabetic patients. Its main advantages are noninvasiveness, repeatability and a high quality of images acquired from the chosen level of the retina.

Renoprotection by remote ischemic conditioning during elective coronary revascularization: A systematic review and meta-analysis of randomized controlled trials

BackgroundRemote ischemic conditioning (RIC) has been recognized an emerging non-invasive approach for preventing acute kidney injury (AKI) in patients undergoing either elective coronary artery bypass graft (CABG) surgery or percutaneous coronary intervention (PCI). On the other hand, accumulating evidence has indicated the involving role of pre-CABG contrast usage for coronary angiography in post-surgery AKI risk. Along with the shortening time delay of CABG after coronary angiography, and the prevalent hybrid coronary revascularization (HCR), the AKI prevention by RIC has faced challenges following coronary revascuralization. MethodsRandomized controlled trials (RCTs) were searched from Pubmed, EMBase, and Cochrane library (until May 2016). The primary outcome was postoperative AKI. The second outcomes were included the requirement for renal replacement therapy (RRT), and in-hospital or 30-day mortality. ResultsTwenty eligible RCTs (CABG, 3357 patients; PCI, 1501 patients) were selected. RIC significantly halved the incidence of AKI following PCI when compared with controls [n=1501; odds ratio (OR)=0.51; 95% CI, 0.32 to 0.82; P=0.006; I2=29.6%]. However, RIC did not affect the incidence of AKI following CABG (n=1850; OR=0.94; 95% CI, 0.73 to 1.19; P=0.586; I2=12.4%). The requirement for RRT and in-hospital mortality was not affected by RIC in CABG (n=2049, OR=1.04, P=0.87; n=1920, OR=0.89, P=0.7; respectively). ConclusionsOur meta-analysis suggests that RIC for preventing AKI following CABG has faced with challenges in terms of AKI, the requirement for RRT, and mortality. However, RIC shows a renoprotective benefit for PCI. Hence, our findings may infer the preserved renal effects of RIC in CABG with preconditioning before the coronary angiography, or in HCR.

Intravascular Ultrasound in the Creation of Transhepatic Portosystemic Shunts Reduces Needle Passes, Radiation Dose, and Procedure Time: A Retrospective Study of a Single-Institution Experience

PurposeTo assess whether intravascular ultrasound (US) guidance impacts number of needle passes, contrast usage, radiation dose, and procedure time during creation of transjugular intrahepatic portosystemic shunts (TIPS). Materials and MethodsIntravascular US–guided creation of TIPS in 40 patients was retrospectively compared with conventional TIPS in 49 patients between February 2010 and November 2015 at a single tertiary care institution. Patient sex and age, etiology of liver disease (hepatitis C virus, alcohol abuse, nonalcoholic steatohepatitis), severity of liver disease (mean Model for End-Stage Liver Disease score), and indications for TIPS (variceal bleeding, refractory ascites, refractory hydrothorax) in conventional and intravascular US–guided cases were recorded. ResultsThe two groups were well matched by sex, age, etiology of liver disease, Child-Pugh class, Model for End-Stage Liver Disease scores, and indication for TIPS (P range = .19–.94). Fewer intrahepatic needle passes were required in intravascular US–guided TIPS creation compared with conventional TIPS (2 passes vs 6 passes, P < .01). Less iodinated contrast material was used in intravascular US cases (57 mL vs 140 mL, P < .01). Radiation exposure, as measured by cumulative dose, dose area product, and fluoroscopy time, was reduced with intravascular US (174 mGy vs 981 mGy, P < .01; 3,793 μGy * m2 vs 21,414 μGy * m2, P < .01; 19 min vs 34 min, P < .01). Procedure time was shortened with intravascular US (86 min vs 125 min, P < .01). ConclusionsIntravascular US guidance resulted in fewer intrahepatic needle passes, decreased contrast medium usage, decreased radiation dosage, and shortened procedure time in TIPS creation.

The case study in telecommunications policy research

Purpose The purpose of this paper is to examine the use of case studies in telecommunications policy research (TPR) and to compare and contrast usage with management, management information systems (MIS) and policy analysis. Design/methodology/approach This paper conducts a comparative analysis that examines the methodologies used to design and select case studies and the various theories used in their analysis. Findings The most sophisticated use of case studies is in management information systems (MIS), distinguishing critical realism, interpretivism and positivism to build theories. In policy analysis and TPR, theories are used to explain case studies, which are chosen as interesting sets of phenomena, rather than as means to extend, falsify or verify theories. Research limitations/implications Researchers in telecommunications policy should consider the approaches taken in MIS to determine whether they might improve their rigor. There is also scope for meta-analyses of the existing pool of case studies. Originality/value This appears to be the first article examining the use of case studies in TPR.

Contrast Induced Nephropathy with Intravenous Iodinated Contrast Media in Routine Diagnostic Imaging: An Initial Experience in a Tertiary Care Hospital.

Background. Contrast induced nephropathy (CIN) is common cause of hospital acquired renal failure, defined as iatrogenic deterioration of renal function following intravascular contrast administration in the absence of another nephrotoxic event. Objectives. Objectives were to calculate incidence of CIN with routine IV contrast usage and to identify its risk factors. Materials and Methods. Study was conducted on 250 patients (having eGFR ≥ 45 mL/min/1.73 m2) receiving intravenous contrast. Various clinical risk factors and details of contrast media were recorded. Patients showing 25% increase in postprocedural serum creatinine value or an absolute increase of 0.5 mg/dL (44.2 mmol/L) were diagnosed as having CIN. Results and Conclusions. Postprocedural serum creatinine showed significant increase from baseline levels. 25 patients (10%) developed CIN. CIN was transient in 21 (84%) patients developing CIN. One patient (4%) developed renal failure and another died due to unknown cause. Dehydration, preexisting renal disease, cardiac failure, previous contrast administration, and volume of contrast had significant correlation with development of CIN (p < 0.05); whereas demographic variables, baseline serum creatinine/eGFR, previous renal surgery, diabetes mellitus, hypertension, nephrotoxic drug intake, abnormal routine hematology, and contrast characteristics had no correlation with CIN. CIN is a matter of concern even in routine imaging requiring intravenous contrast media, in our set-up.

A Novel Foam Contrast Agent Suitable for Fluoroscopic Interventional Procedure: Comparative Study of Physical Properties and Experimental Intervention in Animal Model

In fluoroscopic contrast study for interventional procedure, liquid contrast agent may be diluted in body fluid, losing its contrast effect. We developed a novel contrast agent of “foam state” to maintain contrast effect for enough time and performed a comparative study of physical properties and its usefulness in experimental intervention in animal model. The mean size of microbubble of foam contrast was 13.8 ± 3.6 µm. The viscosity was 201.0 ± 0.624 cP (centipoise) and the specific gravity was 0.616. The foam decayed slowly and it had 97.5 minutes of half-life. In terms of the sustainability in a slow flow environment, foam contrast washed out much more slowly than a conventional contrast. In experimental colonic stent placement, foam contrast revealed significantly better results than conventional contrast in procedure time, total amount of contrast usage, and the number of injections (p < 0.05). Our foam contrast has high viscosity and low specific gravity and maintains foam state for a sufficient time. Foam contrast with these properties was useful in experimental intervention in animal model. We anticipate that foam contrast may be applied to various kinds of interventional procedures.

A Snapshot of the Current State of Residential Broadband Networks

The way in which consumers use the Internet is changing rapidly, and over-the-top video services (OTTV) are a major contributor to this trend. The dramatic rise of OTTV services has led to major changes in the telecommunications sector and greater attention to several important and ongoing public policy debates. We provide an essential component to inform these policy debates: an in-depth descriptive analysis of the rapidly changing way in which consumers use the Internet from a representative sample of consumers. At the core of our contribution are unique data from the spring and summer of 2015 that we acquired from a North American ISP that provides detailed disaggregated high-frequency information on individuals’ Internet usage. We provide insight into temporal patterns in usage within the day, measure persistence in the level and composition of usage across days, and contrast usage patterns for consumers that subscribe to traditional pay TV services (i.e., purchase a bundle of services from the operator) to those that do not. We also present results on how the level and composition of usage for a consumer changes immediately after “cutting the cord” and dropping traditional linear TV service.

Impact of Endovascular Technique on Fluoroscopy Usage: Stent-Assisted Coiling versus Flow Diversion for Paraclinoid Internal Carotid Artery Aneurysms.

Flow diversion is increasingly being utilized for the treatment of internal carotid artery (ICA) aneurysms. The purpose of this study was to evaluate the impact of endovascular technique--flow diversion versus stent-assisted coiling (SAC) on fluoroscopy time in patients treated for wide-neck paraclinoid ICA aneurysms. A retrospective review identified the 20 most recent consecutive patients treated for wide-neck paraclinoid ICA aneurysms by flow diversion and SAC respectively. Fluoroscopy time, cumulative dose area-product (DAP), contrast usage, intra-procedural complications, and total procedure time were collected and compared between the two treatment techniques. Treatment groups were comparable in terms of demographics, contrast usage, and clinical and angiographic outcomes. Flow diversion was associated with a significant reduction in fluoroscopy time (52.0 minutes versus 77.4 minutes), and demonstrated a strong trend towards shorter total procedure time (172 minutes versus 202 minutes). Average patient radiation exposure as measured by DAP was lower in the flow diversion group, 13225 mGy(x)cm(2) versus 15124 mGy(x)cm(2), although this finding was not statistically significant. There was no significant difference in contrast usage between the two groups, 152 ml and 159 (flow diversion and SAC respectively). The rate of complete aneurysm occlusion was higher in the flow diversion group (80% versus 60%). Endovascular treatment of paraclinoid ICA aneurysms with flow diversion is associated with shorter fluoroscopy times compared to stent-assisted coiling. There is also a likely reduction in overall procedure time. These results should be considered when recommending a treatment course for patients with such lesions.

Use of three-dimensional contrast-enhanced duplex ultrasound imaging during endovascular aneurysm repair

Iodinated contrast during endovascular aneurysm repair (EVAR) is used with caution in patients with chronic kidney disease. Contrast-enhanced ultrasound (CEUS) imaging using nonnephrotoxic sulphur hexafluoride microbubble contrast is a novel imaging modality that accurately identifies and characterizes endoleaks during EVAR follow-up. We report our initial experience of using three-dimensional (3D) CEUS imaging intraoperatively as completion imaging after endograft deployment. Our aim was to compare intraoperative 3D CEUS against uniplanar angiography in the detection of endoleak, stent deformity, and renal artery perfusion during EVAR. The study enrolled 20 patients undergoing elective conventional infrarenal EVAR, after which a completion angiogram was performed and the presence of endoleak, renal artery perfusion, or device deformity were recorded. With the patient still under anesthetic, a vascular scientist blinded to angiographic findings performed 3D CEUS and reported on the same parameters. Three endoleaks, one type I and two type II, were detected on uniplanar angiography and 13 endoleaks, 11 type II and two type I, were found using 3D CEUS imaging. Of note, one of these type I endoleaks was not seen on angiography, and this patient underwent balloon moulding of the neck with resolution of the endoleak on repeat imaging. Of the 11 type II endoleaks seen with 3D CEUS imaging, the inflow vessel was identified in nine cases. No graft deformity or limb kinking was seen in any patient. Both renal arteries could be visualized in 10 patients, whereas the target renal artery was seen in 11 patients. In the remaining patients, the renal arteries could not be visualized, mainly due to intra-abdominal gas or patient body habitus. 3D CEUS imaging detected endoleaks not seen on uniplanar digital subtraction angiography, including a clinically important type I endoleak, and was also more sensitive than 2D CEUS imaging for the detection of the source of endoleak. This technology has the potential to supplement or replace digital subtraction angiography for completion imaging to reduce the use of x-ray contrast. Intraoperative 3D CEUS has been applied to allow safe EVAR with ultralow or no iodinated contrast usage in selected cases, without compromising completion imaging.

Reducing costs while maintaining quality in endovascular neurosurgical procedures.

As medical costs continue to rise during a time of increasing medical resource utilization, both hospitals and physicians must attempt to limit superfluous health care expenses. Neurointerventional treatment has been shown to be costly, but it is often the best treatment available for certain neuropathologies. The authors studied the effects of 3 policy changes designed to limit the costs of performing neurointerventional procedures at the University of Michigan. The authors retrospectively analyzed the costs of performing neurointerventional procedures during the 6-month periods before and after the implementation of 3 cost-saving policies: 1) the use of an alternative, more economical contrast agent, 2) standardization of coil prices through negotiation with industry representatives to receive economies of scale, and 3) institution of a feedback method to show practitioners the costs of unused products per patient procedure. The costs during the 6-month time intervals before and after implementation were also compared with costs during the most recent 6-month time period. The policy requiring use of a more economical contrast agent led to a decrease in the cost of contrast usage of $42.79 per procedure for the first 6 months after implementation, and $137.09 per procedure for the most current 6-month period, resulting in an estimated total savings of $62,924.31 for the most recent 6-month period. The standardized coil pricing system led to savings of $159.21 per coil after the policy change, and $188.07 per coil in the most recent 6-month period. This yielded total estimated savings of $76,732.56 during the most recent 6-month period. The feedback system for unused items decreased the cost of wasted products by approximately $44.36 per procedure in the 6 months directly after the policy change and by $48.20 per procedure in the most recent 6-month period, leading to total estimated savings of $22,123.80 during the most recent 6-month period. According to extrapolation over a 1-year period, the 3 policy changes decreased costs by an estimated $323,561.34. Simple cost-saving policies can lead to substantial reductions in costs of neurointerventional procedures while maintaining high levels of quality and growth of services.

Three-dimensional fusion computed tomography decreases radiation exposure, procedure time, and contrast use during fenestrated endovascular aortic repair

Endovascular surgery has revolutionized the treatment of aortic aneurysms; however, these improvements have come at the cost of increased radiation and contrast exposure, particularly for more complex procedures. Three-dimensional (3D) fusion computed tomography (CT) imaging is a new technology that may facilitate these repairs. The purpose of this analysis was to determine the effect of using intraoperative 3D fusion CT on the performance of fenestrated endovascular aortic repair (FEVAR). Our institutional database was reviewed to identify patients undergoing branched or FEVAR. Patients treated using 3D fusion CT were compared with patients treated in the immediate 12-month period before implementation of this technology when procedures were performed in a standard hybrid operating room without CT fusion capabilities. Primary end points included patient radiation exposure (cumulated air kerma: mGy), fluoroscopy time (minutes), contrast usage (mL), and procedure time (minutes). Patients were grouped by the number of aortic graft fenestrations revascularized with a stent graft, and operative outcomes were compared. A total of 72 patients (41 before vs 31 after 3D fusion CT implementation) underwent FEVAR from September 2012 through March 2014. For two-vessel fenestrated endografts, there was a significant decrease in radiation exposure (3400 ± 1900 vs 1380 ± 520 mGy; P = .001), fluoroscopy time (63 ± 29 vs 41 ± 11 minutes; P = .02), and contrast usage (69 ± 16 vs 26 ± 8 mL; P = .0002) with intraoperative 3D fusion CT. Similarly, for combined three-vessel and four-vessel FEVAR, significantly decreased radiation exposure (5400 ± 2225 vs 2700 ± 1400 mGy; P < .0001), fluoroscopy time (89 ± 36 vs 64 ± 21 minutes; P = .02), contrast usage (90 ± 25 vs 39 ± 17 mL; P < .0001), and procedure time (330 ± 100 vs 230 ± 50 minutes; P = .002) was noted. Estimated blood loss was significantly less (P < .0001), and length of stay had a trend (P = .07) toward being lower for all patients in the 3D fusion CT group. These results demonstrate that use of intraoperative 3D fusion CT imaging during FEVAR can significantly decrease radiation exposure, procedure time, and contrast usage, which may also decrease the overall physiologic impact of the repair.

Coronary intervention in anomalous origin of the right coronary artery (ARCA) from the left sinus of valsalva (LSOV): A single center experience

ObjectiveTo assess the technical challenges in percutaneous coronary intervention of Anomalous right coronary artery arising from the left sinus of valsalva. MethodsBetween year 2008 and 2012, a total of 17 patients underwent PCI for an angiographically significant lesion in the right coronary artery of an anomalous origin in the LSOV. Their procedure details such as usage of catheters, radiation time, amount of contrast used were assessed. ResultsA total of 17 patients with anomalous right coronary artery underwent PCI during the above mentioned period. 8 patients had type A origin, 3 had type B origin and the remaining 6 had type C origin. Type A origin RCA were successfully cannulated in 6 patients with Judkins left 5.0 and in 2 patients using Judkins left 4.0. Extra back up (EBU) 3.5 were doing well in 2 patients of Type B origin and the remaining one patient was successfully cannulated using Judkins left 4.0. In type C origin 4 patients had successful cannulation with Amplatz Left 1.0, 1 patient with Amplatz Left 2.0 and 1 patient with Judkins left 4.0. The mean fluoroscopic time was 20.7 min and amount of contrast used was 210 ml. ConclusionPCI of anomalous RCA origin from LSOV requires appropriate guide catheter selection according to the anatomy of origin for successful cannulation and to reduce the contrast usage and radiation exposure.

4F angiography is associated with less contrast usage, shorter procedure time and earlier discharge with preserved diagnostic utility - a comparison with 5F angiography

4F angiography is associated with less contrast usage, shorter procedure time and earlier discharge with preserved diagnostic utility - a comparison with 5F angiography

Enteric and Intravenous Contrast Agents Used in Computed Tomography

OPEN ACCESSMarch 13, 2014Enteric and Intravenous Contrast Agents Used in Computed Tomography Richard Burgner, James Rawson, Janet Munroe, Kandace Klein Richard Burgner Medical College of Georgia at Georgia Regents University Google Scholar More articles by this author , James Rawson Medical College of Georgia at Georgia Regents University Google Scholar More articles by this author , Janet Munroe Medical College of Georgia at Georgia Regents University Google Scholar More articles by this author , Kandace Klein Medical College of Georgia at Georgia Regents University Google Scholar More articles by this author https://doi.org/10.15766/mep_2374-8265.9719 SectionsAboutAbstract ToolsDownload Citations ShareFacebookTwitterEmail AbstractAbstractRecent estimates place the number of CT scans performed annually in the United States at approximately 70 million. Given the cost and radiation exposure, it is critical that CT is appropriate and performed with optimal technique. It is important to highlight the role of the radiologist as not just an interpreter of imaging, but as the expert specialist in the proper use of imaging. Accordingly, this tutorial will provide medical students a basic understanding of CT contrast agents, so that in the future they will be able consult effectively with radiologists and properly educate their patients. This presentation was created so that medical students can learn by reading and visualizing the application of different contrast material. All images provided in this tutorial were taken from our home institution except where indicated. This presentation is designed to be a self-tutorial. However, it is appropriate to also use as a stand-alone lecture. This presentation was originally given as a lecture to third- and fourth-year medical students as part of the daily afternoon lecture series for the introductory radiology clerkship. The presentation has now been incorporated into the radiology clerkship self-tutorial curriculum. This tutorial could be expanded into other modalities including contrast agents used in MRI, diagnostic radiography, etc. Being a general overview could be seen as a limitation of this resource. Each of this presentation's educational objectives could conceivably be expanded into its own tutorial for advanced radiology clerkships or resident training. Finally each institution's CT protocols are different. Thus, this tutorial could serve as a “base” in order to train students and residents the specific protocols used in their home institution. Educational Objectives By the end of this module, the learner will be able to: Understand enteric and intravenous contrast agents used in CT as future ordering providers.Understand the importance of contrast through the use of pictorial examples of imaging.Highlight the importance of communication with radiologists to determine appropriate imaging.Understand the risks, precautions, and concerns related to contrast usage such that proper patient education and preparation can occur. Sign up for the latest publications from MedEdPORTAL Add your email below FILES INCLUDEDReferencesRelatedDetails FILES INCLUDED Included in this publication: Student and Instructors Guide.doc Enteric and Intravenous Contrast Agents Used in CT.pptx To view all publication components, extract (i.e., unzip) them from the downloaded .zip file. Download editor’s noteThis publication may contain technology or a display format that is no longer in use. Copyright & Permissions© 2014 Burgner et al. This is an open-access publication distributed under the terms of the Creative Commons Attribution-NonCommercial-Share Alike license.KeywordsIodineComputed TomographyContrast MediaBariumContrast AgentsCT ScanRadiologistRadiology Disclosures None to report. Funding/Support None to report. Loading ...

Lexical function of pitch in the first language shapes cross-linguistic perception of Thai tones

AbstractDetermining the factors involved in the non-native perception of the pitch patterns of tones is complicated by the fact that all languages use pitch to various extents, whether linguistic (e.g., intonation) or non-linguistic (e.g., singing). Moreover, many languages use pitch to distinguish lexical items with varying degrees of functional load and differences in inventory of such pitch patterns. The current study attempts to understand what factors determine accurate naïve (= non-learner) perception of non-native tones, in order to establish the baseline for acquisition of a tonal L2. We examine the perception of Thai tones (i.e., three level tones, two contour tones) by speakers of languages on a spectrum of lexically contrastive pitch usage: Mandarin (lexical tone), Japanese (lexical pitch accent), English (lexical stress), and Korean (no lexically contrastive pitch). Results suggest that the importance of lexically contrastive pitch in the L1 influences non-native tone perception so that not all non-tonal language speakers possess the same level of tonal sensitivity, resulting in a hierarchy of perceptual accuracy. Referencing the Feature Hypothesis (McAllister et al. 2002), we propose the Functional Pitch Hypothesis to model our findings: the degree to which linguistic pitch differentiates lexical items in the L1 shapes the naïve perception of a non-native lexically contrastive pitch system, e.g., tones.