Comparison of iodinated contrast media for the assessment of atherosclerotic plaque attenuation values by CT coronary angiography: observations in an ex vivo model

OBJECTIVE

To compare the influence of different iodinated contrast media with several dilutions on plaque attenuation in an ex vivo coronary model studied by multislice CT coronary angiography.

METHODS

In six ex vivo left anterior descending coronary arteries immersed in oil, CT (slices/collimation 64×0.625 mm, temporal resolution 210 ms, pitch 0.2) was performed after intracoronary injection of a saline solution, and solutions of a dimeric isosmolar contrast medium (Iodixanol 320 mgI ml(-1)) and a monomeric high-iodinated contrast medium (Iomeprol 400 mgI ml(-1)) with dilutions of 1/80 (low concentration), 1/50 (medium concentration), 1/40 (high concentration) and 1/20 (very high concentration). Two radiologists drew regions of interest in the lumen and in calcified and non-calcified plaques for each solution. 29 cross-sections with non-calcified plaques and 32 cross-sections with calcified plaques were evaluated.

RESULTS

Both contrast media showed different attenuation values within lumen and plaque (p<0.0001). The correlation between lumen and non-calcified plaque values was good (Iodixanol r=0.793, Iomeprol r=0.647). Clustered medium- and high-concentration solutions showed similar plaque attenuation values, signal-to-noise ratios (SNRs) (non-calcified plaque: medium solution SNR 31.3±15 vs 31.4±20, high solution SNR 39.4±17 vs 37.4±22; calcified plaque: medium solution SNR 305.2±133 vs 298.8±132, high solution SNR 323.9±138 vs 293±123) and derived contrast-to-noise ratios (p>0.05).

CONCLUSION

Differently iodinated contrast media have a similar influence on plaque attenuation profiles.

ADVANCES IN KNOWLEDGE

Since iodine load affects coronary plaque attenuation linearly, different contrast media may be equally employed for coronary atherosclerotic plaque imaging.

[Clinical indications for the use of cardiac MRI. By the SIRM Study Group on Cardiac Imaging]

Cardiac magnetic resonance (CMR) is considered an useful method in the evaluation of many cardiac disorders. Based on our experience and available literature, we wrote a document as a guiding tool in the clinical use of CMR. Synthetically we describe different cardiac disorders and express for each one a classification, I to IV, depending on the significance of diagnostic information expected.

Computed tomography coronary angiography in asymptomatic patients

PURPOSE

This study assessed the accuracy of computed tomography coronary angiography (CT-CA) for detecting significant coronary artery disease (CAD; ≥50% lumen reduction) in intermediate/high-risk asymptomatic patients.

MATERIALS AND METHODS

A total of 183 consecutive asymptomatic individuals (92 men; mean age 54±11 years) with more than one major risk factor (obesity, hypertension, diabetes, hypercholesterolaemia, family history, smoking) and an inconclusive or nonfeasible noninvasive stress test result (stress electrocardiography, stress echocardiography, nuclear stress scintigraphy) underwent CT-CA in an outpatient setting. All patients underwent conventional coronary angiography (CAG) within 4 weeks. Data from CT-CA were compared with CAG regarding the presence of significant CAD (≥50% lumen reduction).

RESULTS

Mean calcium score was 177±432, mean heart rate during the CT-CA scan was 58±8 bpm and the prevalence (per-patient) of obstructive CAD was 19%. CT-CA showed single-vessel CAD in 9% of patients, two-vessel CAD in 9% and three-vessel CAD in 0%. Per-patient sensitivity, specificity, positive predictive value and negative predictive value of CT-CA were 100% (90-100), 98% (96-99), 97% (85-99), 100% (97-100), respectively. Positive and negative likelihood ratios were 151 and 0, respectively.

CONCLUSIONS

CT-CA is an excellent noninvasive imaging modality for excluding significant CAD in intermediate/ high-risk asymptomatic patients with inconclusive or nonfeasible noninvasive stress test.

Graft patency and late outcomes for patients with ST-segment elevation myocardial infarction who underwent coronary surgery

Objective: The aim of our study was to assess the long-term clinical outcomes and the grafts patency rates of patients with ST-segment elevation myocardial infarction (STEMI) who underwent urgent or emergency coronary artery bypass grafting (CABG).

Materials: Participants in two previous studies comprising 207 STEMI patients undergoing on-pump (145 patients) or off-pump (62 patients) coronary artery bypass graft (CABG) surgery in our institution were prospectively followed to assess late mortality, graft patency, and major adverse cardiac-related event (MACE) rates. Graft patency was evaluated by multi-detector computed tomography angiography 64-slice scan. Mean times of graft implantation were 38±16 months and 37±14 months in on-pump and off-pump, respectively. Follow-up data were obtained in all patients and was 100% complete.

Results: Late mortality rate was 7.4% (10 patients) in the on-pump and 6.5% (4 patients) in off-pump groups (p=0.45). Five-year overall survival rate (±SE) was 93.5±2.1% and 92.6±1.9% in the off-pump vs on-pump, respectively. Five years’ freedom from cardiac-related death was 94.9±2.9% in the on-pump group vs 96.8±3.2% in the off-pump group (p=0.25). Five years’ freedom from cardiac-related events was 89.7±1.6% in the on-pump group versus 93.5±1.8% in the off-pump group (p=0.32). In all patients, a total of 449/491 (91.5%) grafts were patent. Percentages of overall grafts classified as patent were similar in the on-pump group (90.7% - 322/355 conduits) versus the off-pump group (91% - 133/146 conduits). Graft patency rates were also similar between the two groups with regard to arterial and saphenous vein conduits, and with regard to different branches of the coronary arteries grafted.

Conclusion: Our data suggest that off-pump CABG patients have the same late mortality, MACEs, and graft patency rates as conventional cardioplegic cardiac arrest CABG patients. In our opinion, urgent or emergency CABG for patients with STEMI can be done either way.

Anatomical variants and anomalies of the coronary tree studied with MDCT coronary angiography

Anomalies of the coronary arteries are congenital and in most of the cases asymptomatic, although they may present with severe symptoms such as angina pectoris or cardiac arrest. Multidetector CT coronary angiography (MDCT-CA) permits, through curved multiplanar reconstructions and three-dimensional reformatting, noninvasive visualisation of the coronary tree and its variants and anomalies, providing a more accurate alternative to conventional coronary angiography (CCA). The purpose of this pictorial essay is to describe the main variants and anomalies of the coronary arteries using MDCT imaging with multiplanar and three-dimensional reconstructions.

Prevalence of myocardial bridging and correlation with coronary atherosclerosis studied with 64-slice CT coronary angiography

PURPOSE

This study aimed to assess the prevalence and characteristics of myocardial bridging in patients who underwent multislice computed tomography coronary angiography (MSCT-CA) and to evaluate the correlation between bridged coronary segments and atherosclerosis.

MATERIALS AND METHODS

A total of 277 patients (mean age 60+/-11 years) we consecutively examined with 64-slice MSCT-CA for suspected or known coronary atherosclerosis were retrospectively reviewed for myocardial bridging. Segments proximal and distal to the bridging were evaluated for atherosclerotic plaque, as were the remaining coronary segments.

RESULTS

Myocardial bridging was present in 82 patients (30%, mean age 59+/-12). Bridges were of variable length (<1 cm 58%; 1-2 cm 32%; >2 cm 10%) and depth (superficial 69%, intramyocardial 31%) and frequently localised in the mid-distal segment of the left anterior descending artery (95%). Myocardial bridging cannot be considered a significant risk factor for coronary atherosclerosis (odds ratio 0.49) compared with traditional cardiovascular risk factors. Coronary segments proximal to the bridge showed no atherosclerotic disease (33%), positive remodelling (27%), <50% stenosis (20%) or >50% stenosis (20%). We identified 12 noncalcified, 32 mixed and 17 calcified plaques. The distal segments were significantly less affected (p<0.0001).

CONCLUSIONS

MSCT-CA is a reliable, noninvasive method that is able to depict myocardial bridging and associated atherosclerotic plaque in the proximal segments.

Computed tomography coronary angiography vs. stress ECG in patients with stable angina

PURPOSE

This study compared the role of multislice computed tomography coronary angiography (MSCT-CA) and stress electrocardiography (ECG) in the diagnostic workup of patients with chronic chest pain.

MATERIALS AND METHODS

MSCT-CA was performed in 43 patients (31 men, 12 women, mean age 58.8+/-7.7 years) with stable angina after a routine diagnostic workup involving stress ECG and conventional CA. The following inclusion criteria were adopted: sinus rhythm and ability to hold breath for 12 s. Beta-blockers were administered in patients with heart rate>or=70 beats/minute. In order to identify or exclude patients with significant stenoses (>or=50% lumen), we determined posttest likelihood ratios of stress test and MSCT-CA separately and of MSCT-CA performed after the stress test.

RESULTS

The pretest probability of significant coronary artery disease (CAD) was 74%. Positive and negative likelihood ratios were 2.3 [95% confidence interval (CI) 1.0-5.3] and 0.3 (95% CI: 0.2-0.7) for the stress test and 10.0 (95% CI: 1.8-78.4) and 0.0 (95% CI: 0.0-infinity) for MSCT-CA, respectively. MSCT-CA increased the posttest probability of significant CAD after a negative stress test from 50% to 86% and after a positive stress test from 88% to 100%. MSCT-CA correctly detected all patients without CAD.

CONCLUSIONS

Noninvasive MSCT-CA is a potentially useful tool in the diagnostic workup of patients with stable angina owing to its capability to detect or exclude significant CAD.

Prevalence and characteristics of coronary artery disease in a population with suspected ischemic heart disease using CT coronary angiography: correlations with cardiovascular risk factors and clinical presentation

PURPOSE

This study was undertaken to describe the correlation between the distribution of coronary artery disease (CAD) in a symptomatic population with suspected ischaemic heart disease, cardiovascular risk factors (RF) and clinical presentation.

MATERIALS AND METHODS

we studied 163 patients (mean age 65.5 years; 101 men and 62 women) referred for multidetector computed tomography coronary angiography (MDCT-CA) to rule out CAD. The patients had no prior history of revascularisation or myocardial infarction. We analysed how the characteristics of CAD (severity and type of plaque) can change with the increase in RF and how they are related to different clinical presentations.

RESULTS

patients were divided into three groups according to the number of RF: zero or one, two or three, and four or more. The percentage of coronary arteries with no plaque, nonsignificant disease and significant disease was 55%, 41% and 4%, respectively, in patients with zero or one RF; 27%, 51% and 22%, respectively, in patients with two or three RF; and 19%, 38% and 44%, respectively, in patients with four or more RF. Plaque in patients with nonsignificant disease was mixed in 65%, soft in 18% and calcified in 17%. The percentage of coronaries with no plaque in the three RF groups was 50%, 20% and 0% in patients with typical chest pain and 46%, 24% and 12% in those with atypical pain. The percentage of significant disease in patients with typical pain was 0%, 47% and 86% and in those with atypical pain 4%, 20% and 29%.

CONCLUSIONS

MDCT plays an important role in the identification of CAD in patients with suspected ischaemic heart disease. Severity and type of disease is highly correlated with RF number and assumes different characteristics according to clinical presentation.

Dysphagia: epidemiology, risk factors and impact on quality of life--a population-based study

BACKGROUND

Data on the population epidemiology of dysphagia are scarce. Little is known about the prevalence, risk factors and impact on quality of life of dysphagia in the general community.

AIM

To determine the magnitude and impact of dysphagia in the general community.

METHODS

A random sample of 1000 individuals of Sydney, Australia, were mailed a validated self-report questionnaire to assess dysphagia. Measured were dysphagia symptoms, potential mechanisms, risk factors, psychological disorders, quality of life and demographics.

RESULTS

The response rate of included subjects (n = 926) was 73% (n = 672). Dysphagia ever was reported by 16% (n = 110). Multiple logistic regression analysis found that odynophagia was independently associated with gastro-oesophageal reflux disease (GERD) (OR = 3.41, 95% CI: 1.16-10.04). Intermittent dysphagia was independently associated with GERD (OR = 2.96, 95% CI: 1.76-4.98) and anxiety (OR = 1.09, 95% CI: 1.01-1.19). The presence of progressive dysphagia was independently associated with depression (OR = 1.34, 95% CI: 1.07-1.67). Progressive dysphagia was independently associated with reduced 'general health' (OR = 0.95, 95% CI: 0.90-0.99), while intermittent dysphagia was associated with a reduction in the 'role physical' subscale (OR = 0.98, 95% CI: 0.97-0.99).

CONCLUSIONS

Dysphagia is remarkably common in the general population. GERD is a risk factor for dysphagia as well as odynophagia. Intermittent dysphagia was associated with anxiety, while progressive dysphagia was associated with depression.

Digital cineradiographic study of swallowing in patients with amyotrophic lateral sclerosis

PURPOSE

This study was performed to evaluate the usefulness of digital cineradiography in detecting swallowing disorders in dysphagic patients affected by amyotrophic lateral sclerosis (ALS) with a view to planning an adequate therapeutic approach.

MATERIAL AND METHODS

From January 2005 to September 2006, 23 patients (10 men and 13 women; mean age 41.3+/-8.6 years) affected by ALS were evaluated with digital cineradiography to assess the grade of dysphagia. All patients were classified using the Hillel ALS Severity Scale (ALSSS). All examinations were performed with radiocontrolled equipment provided with a digital C-arm.

RESULTS

The cineradiographic technique enabled us to differentiate patients with disorders of the oral (17/23) and/or pharyngeal (19/23) swallowing phase from those without swallowing dysfunction (4/23). In 14/23 patients, passage of contrast medium into the upper airways was observed during swallowing, whereas in 5/23 cases, aspiration of contrast medium into the lower airways was recorded.

CONCLUSIONS

The videofluoroscopic swallowing study has high diagnostic capabilities in the evaluation of swallowing disorders, as it is able to identify the degree and causes of impairment. In addition, the study proved useful for planning speech therapy and for follow-up in patients with ALS.

Coronary variants and anomalies: methodology of visualisation with 64-slice CT and prevalence in 202 consecutive patients

PURPOSE

This paper aims to provide the tools for a complete anatomical evaluation of the coronary tree using 64-slice computed tomography (CT) and evaluate the prevalence of anatomical variants and anomalies in a population of 202 consecutive patients.

MATERIALS AND METHODS

Two hundred and two patients with suspected coronary artery disease underwent 64-slice CT with a standard protocol. Two observers working in consensus evaluated and collected the data regarding anatomical variants and anomalies of the coronary vessels.

RESULTS

In the 202 consecutive patients, the prevalence of anatomical variants was: left dominant circulation (7%), absent left main (5%), presence of intermediate branch (17%), aortic origin of conus branch (13%) and circumflex origin of sinus node branch (15%). Coronary anomalies (origin and course, intrinsic and termination) showed an overall prevalence of 25%.

CONCLUSIONS

CT is the ideal method for the three-dimensional evaluation of the coronary tree. Anatomical variants and anomalies of the coronary arteries are quite common and should be known and recognised promptly by the operators.

Comprehensive cardiovascular ECG-gated MDCT as a standard diagnostic tool in patients with acute chest pain

Acute myocardial infarction, pulmonary embolism, and aortic dissection are diseases associated with acute chest pain and may lead to severe morbidity and mortality. These diseases may not be trivial to diagnose in the settings of emergency room. ECG-gated multi-detector computed tomography (MDCT), already established for the assessment of pulmonary embolism and aortic dissection, provides reliable information regarding the triage of patients with acute coronary syndrome in the emergency room. MDCT recently appeared to be logistically feasible and a promising comprehensive method for the evaluation of cardiac and non-cardiac chest pain in emergency department patients. The possibility to scan the entire thorax visualizing the thoracic aorta, the pulmonary arteries, and the coronary arteries could provide a new approach to the triage of acute chest pain. The inherent advantage of MDCT with cardiac state-of-the-art capabilities is the rapid investigation of the main sources of acute chest pain with a high negative predictive value. Recent studies also reports an advantage in terms of costs. With current evidence, the selection of patients with acute chest pain candidates to MDCT should remain restricted to avoid unjustified risk of ionizing radiation.

Can ECG-gated MDCT be considered an obligatory step to plan and manage a new chest-pain unit?

The recent improvements in multi-detector computed tomography technology and its application in cardiac field allow to consider this non-invasive imaging technique as a promising comprehensive method for detecting significant coronary stenoses in a chest-pain unit. The possibility to use the ECG-synchronisation acquisition protocol, normally limited to the cardiac volume, for the entire thoracic vascular system should have the remarkable potential to reduce invasive and non-invasive procedures actually used to investigate acute chest pain and the number of unnecessary hospital admissions without reducing appropriate admissions in patients with chest pain.

Imaging techniques for the vulnerable coronary plaque

The goal of this article is to illustrate the main invasive and noninvasive diagnostic modalities to image the vulnerable coronary plaque, which is responsible for acute coronary syndrome. The main epidemiologic and histological issues are briefly discussed in order to provide an adequate background. Comprehensive coronary atherosclerosis imaging should involve visualization of the entire coronary artery tree and plaque characterization, including three-dimensional morphology, relationship with the lumen, composition, vascular remodelling and presence of inflammation. No single technique provides such a comprehensive description, and no available modality extensively identifies the vulnerable plaque. In particular, we describe multislice computed tomography, which at present seems to be the most promising noninvasive tool for an exhaustive image-based quantification of coronary atherosclerosis.

Diagnostic accuracy of 64-slice CT in the assessment of coronary stents

PURPOSE

The purpose of this study was to assess the diagnostic accuracy of 64-slice computed tomography (64-CT) coronary angiography in the detection of coronary in-stent restenosis.

MATERIALS AND METHODS

Ninety-five patients (72 men and 23 women, mean age 58+/-8 years) with previous percutaneous coronary intervention with stenting and suspected restenosis underwent 64-CT (Sensation 64, Siemens). The mean time between stent deployment and 64-CT was 6.1+/-4.2 months. The scan parameters were: slices 32 x 2, individual detector width 0.6 mm, rotation time 0.33 s, feed 3.84 mm/rotation, 120 kV, 900 mAs. After the intravenous administration of iodinated contrast material (Iomeprol 400 mgI/ml, Iomeron, Bracco) and a bolus chaser (40 ml of saline), the scan was completed in <12 s. All coronary segments with a stent were assessed on 64-CT by two observers in consensus and judged as: patent, with intimal hyperplasia (lumen reduction of <50%), with in-stent restenosis (> or =50%), or with in-stent occlusion (100%). The consensus reading was compared with conventional coronary angiography.

RESULTS

Four patients were excluded because of insufficient image quality. In the remaining 91, we assessed 102 stents (31 RCA; 10 LM; 54 LAD; 7 CX). In 14 (13.7%) stents, in-stent restenosis (n=8) or in-stent occlusion (n=6) was found. Intimal hyperplasia was detected in 11 (10.8%) stents. The sensitivity and negative predictive value of 64-CT for in-stent occlusion were 100% and 100%, respectively, whereas for all stenoses, >50% they were 92.9% and 98.7%, respectively.

CONCLUSIONS

We found that 64-CT has a high diagnostic accuracy for the detection of in-stent restenosis in a selected patient population.

Three-dimensional quantitative assessment of lung parenchyma in cystic fibrosis: preliminary results

PURPOSE

The aim of this study was to assess the feasibility of three-dimensional (3D) reconstructions and quantitative analysis of the volume of each component of the lung with cystic fibrosis (CF).

MATERIALS AND METHODS

Twenty-two patients with CF (mean age 17+/-8 years) were included in the study. The patients underwent an unenhanced single-slice spiral computed tomography (CT) chest scan with the following parameters: collimation 3 mm, table feed 6 mm x rot(-1), reconstruction interval 1 mm, soft tissue reconstruction kernel. Four image data sets were obtained: native axial slices, cine-mode display, virtual bronchographic volume-rendered images with algorithm for tissue transition display and virtual endoluminal views. The lungs were segmented manually from the hilum to the visceral pleura on the axial images, and the entire lung volume was calculated. A histogram was generated representing the fractional volume of tissues, the density of which was within a preset range. A curve was then obtained from the histogram.

RESULTS

Native axial images and cine-mode display allowed complete evaluation of lung volumes. Virtual bronchography allowed a better assessment of the distribution of bronchiectasis. Virtual bronchoscopy was limited by the fact that it visualised only the surface, without differentiating mucus from the bronchial wall. Manual segmentation and generation of density-volume curves required 41+/-7 min for each lung. Three curve patterns were identified depending on disease severity.

CONCLUSIONS

Volume-density analysis of lungs with CF is feasible. Its main advantage is that image analysis is not analogical, as the assessment is not performed using scoring systems or similar ordinal scales. This technique cannot differentiate acute from chronic findings, and the predictive value of the curve should be assessed.