Biomedical subjects
Publications and source records attributed to C A Roobottom.
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AIM: To evaluate the diagnostic accuracy of 16-detector row computed tomography (CT) in assessing haemodynamically significant coronary artery stenoses in patients under evaluation for aortic stenosis pre-aortic valve replacement. SUBJECTS AND METHODS: Forty consecutive patients under evaluation for severe aortic stenosis and listed for cardiac catheterization before potential aortic valve replacement underwent coronary artery calcium (CAC) scoring and retrospective electrocardiogram (ECG)-gated multi-detector row computed tomographic coronary angiography (MDCTA) using a GE Lightspeed 16-detector row CT within 1 month of invasive coronary angiography (ICA) for comparative purposes. All 13 major coronary artery segments of the American Heart Association model were evaluated for the presence of > or =50% stenosis and compared to the reference standard. Data were analysed on a segment-by-segment basis and also in "whole patient" terms. RESULTS: A total of 412/450 segments from 35 patients were suitable for analysis. The overall accuracy of MDCTA for detection of segments with > or =50% stenosis was high, with a sensitivity of 81.3%, specificity 95.0%, positive predictive value (PPV) 57.8%, and negative predictive value (NPV) 98.4%. On a "whole-patient" basis, 100% (19/19) of patients with significant coronary disease were correctly identified and there were no false-negatives. Excluding patients with CAC >1000 from the analysis improved the accuracy of MDCTA to: sensitivity 90%, specificity 98.1%, PPV 60%, NPV 99.7%. CONCLUSION: Non-invasive 16-detector row MDCTA accurately excludes significant coronary disease in patients with severe aortic stenosis undergoing evaluation before aortic valve replacement and in whom ICA can therefore be avoided. Its segment-by-segment accuracy is improved further if CAC>1000 is used as a gatekeeper to MDCTA.
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We present the case of an adult female patient with a giant coronary artery aneurysm secondary to Kawasaki disease diagnosed for the first time, as far as the authors are aware, on multi-detector row computed tomography (MDCT). The long-term complications relate to the persistence of these aneurysms with giant coronary aneurysms having the lowest regression rate, the highest risk of stenosis and strongest association with myocardial infarction. MDCT coronary angiography represents an ideal, alternative non-invasive imaging modality for the diagnosis and follow-up of the coronary arterial complications of Kawasaki disease, thereby avoiding invasive coronary imaging, and its use in the management algorithm should be considered. We also aim to contribute to the expanding clinical role of MDCT coronary imaging.
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AIMS: To evaluate the success of two different types of wire in common use in their ability to successfully cannulate the superficial femoral artery (SFA) using antegrade puncture. METHODS: 50 consecutive patients in whom antegrade infra-inguinal intervention was planned, underwent common femoral arterial puncture and then cannulation with either a standard 3mm 'J' wire or a floppy tipped straight wire (William Cook-Europe). The frequency with which each type of wire entered the SFA or profunda femoris artery without image guidance was recorded. Further analysis was also made of the success of manipulation of the wire into the SFA following profunda cannulation and the use of alternative guide wires. RESULTS: In 19 out of 25 (76%) patients the 'J' wire correctly entered the SFA without image guidance. Only 5 out of 25 (25%) of straight wires entered the SFA with the initial pass (p < 0.0001). Following further manipulation with the same wire all except 1 'J' wire was successfully negotiated into the SFA. The same was true for only 9 of the remaining straight wires with 11 patients requiring an alternative guide wire. CONCLUSIONS: When performing antegrade cannulation of the SFA a 'J' wire is more likely to be successful than a straight guide wire.
AIM: To assess whether multi-detector CT angiograms (MDCTA) of the lower limb arteries, compared with conventional digital subtraction angiograms (DSA), could replace invasive arteriography in patients with symptomatic peripheral arterial disease. MATERIALS AND METHODS: In a prospective comparative analysis of MDCTA and DSA in 44 patients, MDCTA was analyzed using volume-rendered images acquired at a workstation and viewed in tandem with the original axial data. Designated arterial segments were graded according to their degree of stenosis. RESULTS: We found agreement for the degree of stenosis in 88.8% and 85.4% of 1024 segments analysed for two observers. The sensitivity for treatable lesions (>50% stenosis) was 79.1% and 72% with a specificity of 93.3% and 92.6%. DSA failed to visualize 7.3% of segments that were visible with MDCTA. These segments were exclusively downstream to long segment occlusions. CONCLUSION: MDCTA using 4-slice machines is insensitive to detecting significant arterial stenoses in the lower limb arteries. MDCTA is superior to DSA in its visualization of arterial territories downstream to significant occlusive disease.
Over the last 2 years, multi-detector row computed tomographic (MDCT) cardiac imaging has continued to rapidly develop and evolve from the experimental research setting to become a useful clinical tool. The increasing availability of MDCT presents today's clinicians with an additional non-invasive diagnostic cardiac imaging method, in particular for the coronary arteries. With the advent and increasing clinical use of 16-detector row machines, and now with the imminent clinical emergence of 64-channel machines, the improvements in spatial and temporal resolution and sophisticated ECG-gating are allowing motion-free, fast, accurate, detailed, contrast-enhanced cardiac imaging that begins to approach the accuracy of traditional invasive diagnostic techniques. Additional diagnostic information may also be provided.
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Acute aortic syndromes (AAS) encompass a spectrum of emergencies. These include those non-traumatic disease entities of the aorta namely, penetrating atherosclerotic ulcer, intramural haematoma, dissection and aneurysm rupture. The various types of AAS cannot be reliably differentiated on clinical grounds alone. Acute thoracic aortic injury is usually included in this group even though clinical presentation is different, i.e., in the context of trauma, the imaging features are very similar. Differentiation of AAS from acute coronary syndrome (ACS) is important, however, it must be remembered that ACS may occur as a result of AAS. Now electrocardiogram (ECG)-gating technology is widely available, ECG-gated multi-detector row computed tomography (MDCT) is a powerful clinical tool in the acute emergency setting, which enables rapid and specific diagnosis of aortic pathology. ECG-gated MDCT significantly reduces motion artefact, avoids potential pitfalls in diagnosis and often provides diagnostic information about the coronary arteries. It should be used as a first-line imaging technique. This article examines the role of MDCT imaging and cardiac gating in the assessment of AAS and discusses the differentiation of this spectrum of aortic diseases with reference to the key imaging findings as obtained by experience in our institution.
AIM: Although arterial closure devices are in use for over a decade, there have been no specific study to assess the use of the same in antegrade puncture. MATERIAL AND METHOD: Consecutive patients undergoing antegrade puncture for peripheral vascular disease in a single centre performed by a single operator were included in this study. The notes and the angiograms were reviewed retrospectively for possible complications and the severity of disease. RESULT: Over a 25-month period, 21 patients with antegrade puncture had Angioseal deployed for haemostasis. Post-procedure complications recorded from the case notes showed one episode of haematoma formation and one case of worsening ischaemia. The severity of the disease at the puncture site did not influence the outcome. CONCLUSION: Use of Angioseal is safe and effective in antegrade punctures for peripheral vascular disease. The result is independent of the severity of disease at the puncture site.
OBJECTIVE: To assess submillimetre coronary computed tomographic angiography (CTA) in comparison with invasive quantitative coronary angiography as the gold standard and to examine the effect of significant coronary artery calcification (CAC), which is known to impede lumen visualisation, on the accuracy of the examination. METHODS: After invasive coronary angiography, 58 patients underwent coronary imaging with a GE Lightspeed 16 computed tomography (CT) system. CAC was quantified after an ECG triggered acquisition with a low tube current. Coronary CTA was performed with retrospective ECG gating and a 16 x 0.63 mm collimation and was reconstructed with an effective 65-250 ms temporal resolution. All 13 major coronary artery segments were evaluated for the presence of > or = 50% stenosis, and compared with the gold standard. RESULTS: One patient moved and could not be evaluated. All segments (except occluded segments) were evaluated for 57 patients. Overall the accuracy of coronary CTA for detection of > or = 50% stenosis was: sensitivity 83%, specificity 97%, positive predictive value 80%, and negative predictive value 97%. The number of diseased coronary arteries was correctly diagnosed in 34 of 38 (89%) patients overall. Altogether 21 of 57 (37%) patients had a CAC score > or = 400, which was predefined as representing significant CAC. Excluding these patients from the analysis improved the accuracy of coronary CTA to a sensitivity of 89%, specificity 98%, positive predictive value 79%, and negative predictive value 99%. CONCLUSIONS: Non-invasive coronary angiography with submillimetre CT is reliable and accurate. It appears that a subgroup of patients may be selected based on CAC score in whom the investigation has even higher accuracy. Coronary CTA has reached the stage where it should be considered for a clinical role. Further research is required to define this role.
The quality of the imaging of the main coronary arteries and side branches provided by multidetector row computed tomography (MDCT) may have importance when assessing congenital coronary artery anomalies. This review discusses the rationale for using MDCT for this indication and examines the advantages and disadvantages of the technique. Examples of MDCT imaging of congenital coronary artery anomalies are presented. These images provide persuasive evidence to support clinical use of MDCT cardiac imaging in the context of suspected congenital coronary artery anomalies as a first line investigation.
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AIM: To evaluate the technique of coronary angiography with retrospectively electrocardiogram (ECG)-gated four-slice helical computed tomography (CT). MATERIALS AND METHODS: Within 1 month of undergoing routine day-case diagnostic coronary angiography, 30 consecutive patients also underwent retrospectively ECG-gated multislice CT coronary angiography. This enabled direct comparison of seven segments of proximal and mid-coronary artery for each patient by two blinded assessors. Each segment of coronary artery from the multislice CT image was evaluated initially for "assessability" and those segments deemed assessable were subsequently investigated for the presence or absence of a significantly (n=70%) stenotic lesion. RESULTS: Overall 68% of proximal and mid-coronary artery segments were assessable. The sensitivity and specificity of four-slice CT coronary angiography in assessable segments for detecting the presence or absence (n=70%) of stenoses were 72 and 86%, respectively. These results correspond to a positive predictive value of 53% and a 93% negative predictive value. If the 32% of non-assessable segments are added into the calculation then the sensitivity and specificity fall to 49 and 66%, respectively. CONCLUSION: Although multislice CT coronary angiography is a promising technique, the overall assessability and diagnostic accuracy of four-slice CT acquisition is not sufficient to justify routine clinical use. Further, evaluation should investigate the benefit of the reduction in temporal and spatial resolution offered by 16 and 32 slice acquisition.