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Delayed contrast-enhanced cardiovascular magnetic resonance (DE-CMR) allows assessment of reversibility of myocardial dysfunction. Comparative data to other modalities is scarce. Purpose of this study was to compare DE-CMR and (201)Thallium single photon emission computed tomography (SPECT) for prediction of reversible left ventricular (LV) dysfunction in patients with chronic ischaemic heart disease. Fifty-four patients with LV dysfunction (mean ejection fraction (EF) 35 ± 8%) scheduled to undergo myocardial revascularization underwent DE-CMR and SPECT. Cine CMR was performed at baseline and at 8 months follow-up for assessment of regional and global myocardial function. Myocardial viability was determined by the segmental extent of delayed enhancement for DE-CMR, and by quantitative analysis of tracer uptake for SPECT, and was correlated to functional recovery after revascularization. After revascularization, 172 (49%) of 350 dysfunctional segments improved at follow-up cine CMR. Sensitivity and specificity for the prediction of functional recovery was 92 and 88%, respectively, for DE-CMR as compared to 86% (P = 0.4) and 56% (P = 0.001) for SPECT. Global LV function showed an increase of EF > 5% in 22 (41%) patients. The DE-CMR derived viability ratio (dysfunctional but viable myocardium) of 0.46 (sensitivity 91%, specificity 91%) was identified as predictor of increase in EF > 5% (P = 0.02), whereas the corresponding SPECT parameters were not predictive. DE-CMR compares favorably to SPECT for the prediction of regional and global improvement in LV function in the setting of chronic myocardial ischemia. [ABSTRACT FROM AUTHOR]

Objectives: Transcatheter Aortic Valve Implantation (TAVI) is an alternative to surgical valve replacement in high risk patients. Angiography of the aortic root, aorta and iliac arteries is required to select suitable candidates, but contrast agents can be harmful due to impaired renal function. We evaluated ECG-triggered high-pitch spiral dual source Computed Tomography (CT) with minimized volume of contrast agent to assess aortic root anatomy and vascular access.Methods: 42 patients (82 ± 6 years) scheduled for TAVI underwent dual source (DS) CT angiography (CTA) of the aorta using a prospectively ECG-triggered high-pitch spiral mode (pitch = 3.4) with 40 mL iodinated contrast agent. We analyzed aortic root/iliac dimensions, attenuation, contrast to noise ratio (CNR), image noise and radiation exposure.Results: Aortic root/iliac dimensions and distance of coronary ostia from the annulus could be determined in all cases. Mean aortic and iliac artery attenuation was 320 ± 70 HU and 340 ± 77 HU. Aortic/iliac CNR was 21.7 ± 6.8 HU and 14.5 ± 5.4 HU using 100 kV (18.8 ± 4.1 HU and 8.7 ± 2.6 HU using 120 kV). Mean effective dose was 4.5 ± 1.2 mSv.Conclusions: High-pitch spiral DSCTA can be used to assess the entire aorta and iliac arteries in TAVI candidates with a low volume of contrast agent while preserving diagnostic image quality. [ABSTRACT FROM AUTHOR]

Objective: To investigate the prevalence and diagnostic value of first-pass myocardial perfusion defects (PD) visualised by contrast-enhanced multidetector computed tomography (MDCT) in patients admitted for a first acute coronary syndrome (ACS).Methods: Thirty-eight patients with non-ST segment elevation myocardial infarction (NSTEMI) or unstable angina (UA) and scheduled for percutaneous coronary intervention underwent dual-source CT immediately before catheterisation. CT images were analysed for the presence of any PD by using a 17-segment model. Results were compared with peak cardiac troponin-I (cTnI) and angiography findings.Results: PD were seen in 21 of the 24 patients with NSTEMI (median peak cTnI level 7.07 ng/mL; range 0.72-37.07 ng/mL) and in 2 of 14 patients with UA. PD corresponded with the territory of the infarct-related artery in 20 out of 22 patients. In a patient-based analysis, sensitivity, specificity, negative and positive predictive values of any PD for predicting NSTEMI were 88%, 86%, 80% and 91%. Per culprit artery, the respective values were 86%, 75%, 80% and 83%.Conclusion: In patients with non-ST segment elevation ACS, first-pass myocardial PD in contrast-enhanced MDCT correlate closely with the presence of myocardial necrosis, as determined by increases in cTnI levels. [ABSTRACT FROM AUTHOR]

Objective: To evaluate staged low-dose approaches for coronary CT angiography (CTA) in which a standard sequence was added if the low-dose sequence did not allow reliable rule-out of coronary stenosis.Patients and Methods: A total of 176 consecutive patients referred for dual-source CTA were randomized to three protocols: group 1 using prospective ECG-triggering (100 kV, 330 mAs), group 2 a retrospectively gated "MinDose" sequence (100 kV, 330 mAs) and group 3 a standard spiral sequence (120 kV, 400 mAs). If image quality in low-dose groups 1 or 2 was non-diagnostic, an additional standard CT examination (as in group 3) was performed.Results: Non-diagnostic image quality was found in 11/56, 4/55, and 2/65 patients (46/896, 4/880 and 3/1,040 coronary segments) in groups 1, 2 and 3, respectively. Median (interquartile ranges) volumes of contrast material, CTDI(vol), DLP and effective dose for low-dose groups 1 and 2 and for standard group 3 were 92.5 (11.3), 75.0 (2.5) and 75.0 (9.0) ml; 8.0 (1.4), 16.8 (4.8) and 48.1 (14.2) mGy; 108.0 (27.3), 246.0 (93.0) and 701.0 (207.8) mGy cm; and 1.5 (0.4), 3.4 (1.3) and 9.8 (2.9) mSv, respectively.Conclusion: A staged coronary CTA protocol with an initial low-dose approach and addition of a standard sequence--should image quality be too low--can lead to a substantial reduction in radiation exposure. [ABSTRACT FROM AUTHOR]

Objective: We evaluated radiation exposure and image quality of a new coronary CT angiography protocol, high-pitch spiral acquisition, using dual source CT (DSCT).Material and Methods: Coronary CTAwas performed in 25 consecutive patients with a stable heart rate of 60 bpm or less after premedication, using 2 x 128 0.6-mm sections, 38.4-mm collimation width and 0.28-s rotation time. Tube settings were 100 kV/320 mAs and 120 kV/400 mAs for patients below and above 100-kg weight, respectively. Data acquisition was prospectively ECG-triggered at 60% of the R-R interval using a pitch of 3.2 (3.4 for the last 10 patients). Images were reconstructed with 75-ms temporal resolution, 0.6-mm slice thickness and 0.3-mm increment. Image quality was evaluated using a four-point scale (1 = excellent, 4 = unevaluable).Results: Mean range of data acquisition was 113 +/- 22 mm, mean duration was 268 +/- 23 ms. Of 363 coronary artery segments, 327 had an image quality score of 1, and only 2 segments were rated as "unevaluable". Mean dose-length product (DLP) was 71 +/- 23 mGy cm, mean effective dose was 1.0 +/- 0.3 mSv (range 0.78-2.1 mSv). For 21 patients with a body weight below 100 kg, mean DLP was 63 +/- 5 mGy cm (0.88 +/- 0.07 mSv; range 0.78-0.97 mSv).Conclusion: Prospectively ECGtriggered high-pitch spiral CT acquisition provides high and stable image quality at very low radiation dose. [ABSTRACT FROM AUTHOR]

Background: Multidetector CT allows detection of coronary artery calcium and, after contrast injection, visualisation of the coronary artery lumen. It is commonly assumed that the absence of coronary calcification makes the presence of obstructive coronary lesions highly unlikely. This study evaluates the clinical characteristics of patients with at least one symptomatic, high-grade coronary artery stenosis in both computed tomography and invasive angiography but absence of any coronary calcification and compares the results with patients with stenoses in the setting of detectable coronary calcium Patients and Methods: The study retrospectively identified 21 consecutive patients with symptoms in whom a high-grade coronary artery stenosis had been identified in 64-slice or dual-source CT coronary angiography (Siemens Sensation 64 or Siemens Definition, 120 kV, 50 to 85 ml of intravenous contrast at 5 ml/s) in the absence of coronary calcium and in whom that finding had been confirmed by invasive coronary angiography. Clinical presentation ("unstable": all forms of acute coronary syndrome versus "stable": stable chest pain or dyspnoea on exertion) and standard cardiovascular risk factors were assessed, and the results were compared with 42 consecutive patients with symptoms in whom both coronary calcium and coronary stenoses had been identified in computed tomography and invasive coronary angiography. Results: The majority of patients with coronary stenoses in the absence of coronary calcium presented with "unstable" symptoms (non-ST-segment elevation myocardial infarction (NSTEMI) or unstable angina), significantly more frequently than patients with detectable calcification (71% vs 26%, p = 0.001). The age range of patients without calcium was 33 to 76 years, their mean age was younger (53 (SD 13) vs 63 (8) years, p<0.001), but none of the risk factors showed any significant difference compared with patients with calcification. Conclusion: The presence of significant coronary artery stenosis in the absence of coronary calcium is possible. It is more likely in the setting of unstable angina or NSTEMI than in stable chest pain and occurs more frequently in younger patients. [ABSTRACT FROM AUTHOR]

In coronary CT angiography (CTA), both high-grade stenoses and total occlusions of a coronary artery may appear as a complete interruption of the contrast-enhanced lumen. Parameters to differentiate between occlusions and stenoses have not been systematically assessed. We evaluated 40 consecutive patients with a lesion demonstrating complete interruption of the contrast-enhanced lumen in coronary CTA and in whom invasive coronary angiography was available. Length of the vessel segment without luminal contrast enhancement; luminal enhancement proximal, in and distal to the lesion; degree of coronary remodelling; and the degree of lesion calcification were assessed by a blinded observer unaware of the invasive angiogram. Mean length of complete occlusions (n = 20; range 4-54 mm; mean 16.6 +/- 3.5 mm) was significantly longer than for high-grade stenoses (n = 20; 2-8 mm; mean 4.6 +/- 1.7 mm, p < 0.001). A lesion length > or = 9 mm was 100% specific and 70% sensitive for an occlusion. No significant differences were found for vessel enhancement in or distal to the lesion, remodelling index or degree of calcification. Lesion length is the only parameter that may differentiate complete occlusions and high-grade stenoses in coronary CTA. For lesions > or = 9 mm, an occlusion is very likely. [ABSTRACT FROM AUTHOR]