Search for charged Higgs bosons in e+e- collisions at [Formula: see text].

A search is made for charged Higgs bosons predicted by Two-Higgs-Doublet extensions of the Standard Model (2HDM) using electron-positron collision data collected by the OPAL experiment at [Formula: see text], corresponding to an integrated luminosity of approximately 600 pb-1. Charged Higgs bosons are assumed to be pair-produced and to decay into [Formula: see text], τντ or AW±. No signal is observed. Model-independent limits on the charged Higgs-boson production cross section are derived by combining these results with previous searches at lower energies. Under the assumption [Formula: see text], motivated by general 2HDM type II models, excluded areas on the [Formula: see text] plane are presented and charged Higgs bosons are excluded up to a mass of 76.3 GeV at 95 % confidence level, independent of the branching ratio BR(H±â†’τντ ). A scan of the 2HDM type I model parameter space is performed and limits on the Higgs-boson masses [Formula: see text] and mA are presented for different choices of tanß.

Management of iatrogenic porto-biliary fistula following biliary stent.

We describe a case of cystic pancreatic disease causing biliary obstruction requiring percutaneous biliary stenting. The patient subsequently re-presented with severe melaena shown to be due to a rare complication of biliary stenting with development of a porto-biliary fistula from stent erosion, successfully managed with a 'stent-within-stent'.

Discrepancy between computed tomography coronary angiography and selective coronary angiography in the pre-stenting assessment of coronary lesion length.

We aimed to compare the lesion length measured on computed tomography coronary angiography (CT-CA) with the selective coronary angiography (SCA) lesion length measured on quantitative coronary angiography (QCA). Compared with SCA, CT-CA has the advantage of showing the lumen and the atherosclerotic plaque in the arterial wall. This prospective observational study involved 44 coronary lesions. Computed tomography coronary angiography was carried out with an electrocardiogram-gated 16-slice CT before percutaneous coronary intervention. A cardiologist and a radiologist measured CT lesion lengths in consensus, whereas an interventional cardiologist carried out QCA to obtain SCA lesion lengths independently. The median difference of (CT lesion length - SCA lesion length) was 9.84 mm (95%CI: [7.26, 13.34]). The median difference of (stent length - SCA lesion length) was 7.68 mm (95%CI: [6.29, 9.26]); the median difference of (stent length - CT length) was -2.63 mm (95%CI: [-5.80, 0.05]). The mean ratio of stent length to SCA lesion length was 2.07 (95%CI: [1.83, 2.30]). The mean ratio of stent length to CT-CA lesion length was 0.97 (95%CI: [0.83, 1.11]). In the subgroup of drug-eluting stents (17 lesions), the median difference of (stent length - SCA lesion length) was 9.76 mm (95%CI: [6.59, 13.28]); the median difference of (stent length - CT length) was -5.2 mm (95%CI: [-11, 0.5]). The mean ratio of stent length to CT-CA lesion length was 0.93 (95%CI: [0.68, 1.17]). Computed tomography lesion length was substantially longer than SCA lesion length measured by QCA. Routine practice of choosing stent length based on QCA may underestimate the actual length of target lesion. This may lead to incomplete coverage of the target lesion, particularly when drug-eluting stents are used.

Diagnostic accuracy of 16-slice CT coronary angiography in the evaluation of coronary artery disease.

Multislice CT coronary angiography (CT-CA) has emerged as a potential imaging method for coronary artery disease. This study aimed to ascertain the accuracy of 16-slice CT in the diagnosis of significant coronary stenosis (>or=50% reduction of lumen diameter). This mixed retrospective/prospective observational study compared 95 paired 16-slice CT-CA and fluoroscopic coronary angiography (FCA) sets. A cardiologist and a radiologist blinded to the FCA findings evaluated CT-CA images independently by visual estimation. Disagreement between these reporters was arbitrated by a third CT reporter (a cardiologist). A separate cardiologist blinded to CT-CA findings assessed FCA by visual estimation. Of 1,161 coronary segments assessable on FCA, 1,103 segments (95%) were assessable on CT-CA. The CT-CA correctly diagnosed 147/180 segments with significant stenoses (sensitivity = 82%) and correctly identified 874/923 coronary segments without significant stenoses (specificity = 95%). The positive and negative predictive values of CT-CA in the diagnosis of coronary segment with significant stenosis were 75 and 96%, respectively. On patient-based analysis, CT-CA correctly identified all 68 studies with at least one vessel with significant stenosis (sensitivity = 100%; specificity = 83%). The positive and negative predictive values of CT-CA in identifying patients with significant coronary stenosis were 94 and 100%, respectively. The 16-slice CT-CA showed moderately good sensitivity but very high specificity and negative predictive value in the diagnosis of significant coronary stenosis. The CT-CA would appear to be a useful 'rule-out' test for patients with low-risk profile for ischaemic heart disease.

Non-invasive computed tomography angiography in the assessment of coronary stent patency: an Australian experience.

BACKGROUND: This study aimed to evaluate the feasibility and accuracy of 16-slice computed tomography (CT) in the assessment of coronary stent patency. CT coronary angiography (CA) has a high degree of accuracy in the assessment of coronary artery disease compared with invasive selective CA. However, its accuracy in the evaluation of stent patency is not well investigated. METHODS: We conducted a retrospective observational study of paired CT coronary angiography (CT-CA) and invasive fluoroscopic coronary angiography (FCA) in 37 patients with 47 coronary stents. CT-CA was carried out with an electrocardiogram-gated 16-slice CT (LightSpeed-16, General Electric (GE), WI, USA). Two CT reporters, blinded to the FCA findings, assessed CT images for stent patency. A cardiologist blinded to CT findings reported FCA. FCA was regarded as the reference standard. RESULTS: A CT-CA could assess 45 of 47 coronary stents (96%). Non-assessable stents on CT-CA were due to motion artefacts and stent-blooming effects. Of those 45 assessable stents, CT-CA correctly identified five out of seven stents with binary in-stent restenosis (ISR) and 37 of 38 stents without binary ISR. The sensitivity and specificity of 16-slice CT in the evaluation of coronary stents for binary ISR were 71% (95% confidence interval (CI) (29%, 96%)) and 97% (95%CI (86%, 100%)), respectively, exclusive of non-assessable stents. The positive and negative predictive values of 16-slice CT were 83% (95%CI (36%, 100%)) and 95% (95%CI (83%, 99%)), respectively. CONCLUSION: Sixteen-slice CT has a low sensitivity, but very a high specificity when compared with FCA in the evaluation of coronary stents for ISR.

Exchanging dual-lumen central venous catheters: how I do it.

The management of a blocked long-term central venous catheter has traditionally been removal and re-siting, even when device failure is not associated with venous thrombosis or sepsis. It is not possible to 'railroad' a split dual-lumen central venous catheter down a long tortuous s.c. tunnel. Our exchange technique was designed to salvage the tunnel and venous access site in a long-term catheter that has had uncomplicated primary device failure. In this technique we divide the dual-lumen catheter and secure the venous access site and the s.c. tunnel with separate peel-away sheaths. The new catheter is then introduced in the conventional manner through the two peel-away sheaths, which are then removed. The key advantage of the technique is that it preserves one of the few central venous access sites available. This article describes exchange of an internal jugular catheter, but the same technique is applicable to subclavian catheters.

Determining the proportion of coronary segments assessable on 16-slice CT coronary angiography: a brief report.

Computed tomography coronary angiography (CT-CA) is becoming a popular non-invasive coronary imaging method. We aimed to determine the proportion of coronary segments assessable on a 16-slice CT in comparison with conventional selective coronary angiography (SCA). We identified all patients who had both 16-slice CT-CA and recent SCA (less than 12 months) from March 2004 to July 2005. Two CT reporters blinded to SCA independently classified coronary segment assessability on CT-CA. A cardiologist blinded to CT findings classified assessability of coronary segments on SCA. Data were analysed using descriptive statistics and proportion of agreement. Ninety-five study pairs were included in the analysis. Of those, 1161 coronary segments were deemed assessable on SCA and 1103 segments (95%) were also assessable on CT-CA. Nonassessable segments on CT-CA were predominantly in the distal segments and branches of coronary arteries. Reasons for nonassessability were small calibre (48.3%), motion artefacts (20.7%) and poorly reconstructed segments (22.4%). The 16-slice CT was able to assess a high proportion of but not all coronary segments. Nonassessable segments were predominantly distal segments or branches of coronary arteries. Motion artefacts due to heart-rate changes, small calibre and poorly reconstructed images were main causes of nonassessability on 16-slice CT-CA.

Use of intra-arterial multi-detector row CT angiography for the evaluation of an ischaemic limb in a patient with renal impairment.

The vastly improved scanning speed and z-axis resolution afforded by multi-detector technology has allowed CT to refine its traditional roles and to explore many new applications in imaging. We present a case report of a patient with renal failure and an ischaemic leg, which illustrates a useful new CT vascular imaging application. By carrying out 16-channel multi-detector row CT angiography through a sheath introduced into the common femoral artery, we obtained a high-quality angiographic image of the affected leg, using only 30 mL of iodinated contrast material. The examination definitively showed the number, distribution and patency of the tibial run-off arteries, with significant influence on the patient's subsequent clinical management. This simple and relatively minimally invasive technique is useful in peripheral vascular imaging, when conventional CT angiography using a large volume of i.v. contrast and MR angiography are unsuitable or unavailable.

Rectal guiding tube to facilitate distal colonic stent insertion.

Self-expanding metallic stents for the treatment of acute colonic obstruction is a recent technique showing promising results. Traditionally metallic stents have used a colonoscope as the portal for stent insertion. Our rectal guiding tube has been devised to enable continuous opacification of the colon without contrast or colonic content leakage and provide a rigid portal through which to insert the metallic stent safely. In many situations concomitant use of a colonoscope is not necessary, especially in left-sided or more distal colonic lesions.

Non-invasive multislice computed tomography coronary angiography for imaging coronary arteries, stents and bypass grafts.

Abstract Multislice computed tomography (MSCT) is evolving rapidly and available data suggest that MSCT coronary angiography may be a reliable and accurate non-invasive imaging modality of coronary arteries. Current generations of MSCT scanners have high sensitivity and specificity for diagnosing native coronary artery disease and coronary bypass graft occlusion. The performance of MSCT in the evaluation of stent patency is still being assessed. In comparison with conventional selective coronary angiography (SCA), MSCT is non-invasive, cheaper and it has the advantages of imaging plaque compositions as well as assessment of luminal patency. Nevertheless, the role of MSCT in the management of coronary artery disease is yet to be fully defined.

Interpreting urgent brain CT scans: Does review by a radiology trainee make a difference in accuracy?

An urgent brain CT scan is now commonly performed on patients presenting to hospital emergency departments for a wide variety of indications. At most institutions in Australia, such scans are reviewed immediately by an on-call radiologist, who is usually an accredited registrar. The value of the trainee radiologist in such a setting is unclear. In the present study, the rate of abnormal findings in a random sample of 100 brain CT scans performed on hospital patients is reviewed and the accuracy of detection of potentially urgent lesions is compared between three junior clinicians, an accredited radiology registrar and a junior radiographer, using the final radiological report as the standard of reference. At least one potentially urgent abnormality in 25% of the patients scanned was found. The RANZCR trainee recorded a significantly higher sensitivity compared to the other readers. It is concluded that an urgent brain CT is of greater value as a screening test if a contemporaneous radiological review is made available, and the implications this may have on current imaging practices are briefly considered.