Cardiac Magnetic Resonance with Delayed Enhancement of the Right Ventricle in patients with Left Ventricle primary involvement: diagnosis and evaluation of functional parameters

Cardiac Magnetic Resonance (CMR) allows an accurate Right Ventricle (RV) assessment that could be of great relevance in diseases causing inflammation or fibrosis. The aim of this study was to evaluate the concomitant involvement of the RV in patients with delayed enhancement (DE) of the Left Ventricle (LV-DE) using CMR. We retrospectively enrolled 95 (male n. 66; age 55±18years; BMI 26±5kg/m2) consecutive patients with LV-DE who underwent a CMR (Achieva 1.5 T, Philips) for different indications: post-ischemic dilated cardiopathy (PDM), hypertrophic cardiomyopathy (HCM), myocardial infarction (MI), myocarditis/pericarditis (MP) and congenital heart disease (CD). We assessed the presence and extension of DE and functional parameters such as ventricular end-diastolic (EDV), end-systolic volumes (ESV) and ejection fraction (EF) of both LV and RV. Prevalence of RV-DE was 30.5% (29/95): 75% (3/4) for CD, 44% (4/9) for PDM, 36% (17/47) for MI, 27.8% (5/18) for MP and 0% (0/17) for HCM. LV-EF and RV-EF were 53±15mL and 51±13mL, respectively, for patients without RV-DE (RV-DE-), and 40±19 mL and 42±15 mL, respectively, for patients with RV-DE (RV-DE+) (p<0.05), while LV-EDV and LV-ESV were 80±28 mL and 40±26 mL, respectively, for RV-DE- and 100±45 mL and 65±49 mL, respectively, for RV-DE+ (p<0.05). The prevalence of RV-DE in patients with LV primary involvement is not negligible and it is found mainly in patients with CD and PDM and then in patients with MI and MP. It is more often associated with LV-EF and RV-EF reduction and increase in LV volumes.

ECG-gated multislice Computed Tomography angiography as a comprehensive non-invasive imaging tool in patient with aortic coarctation

We describe a case of a 52-year-old-woman with aortic coarctation demonstrated by means of 40-slice MSCT angiography. Based on the information extracted from MSCT it was possible to display the anatomical configuration of the disease, the thoraco-abdominal collateral pathways. The best therapeutic approach was established on the basis of MSCT findings. MSCT is a reliable and comprehensive tool for the assessment of adult patients with aortic coarctation. (www.actabiomedica.it)

Idiopathic herniation of the thoracic spinal cord

Since 1974, when Wortzman et al were the first to describe a case of idiopathic spinal cord herniation (ISCH), the number of reported cases has increased owing to magnetic resonance imaging (MRI) now is routinely available for patients with myelopathy and spinal surgeons are becoming more familiar with this clinical entity. This extremely rare herniation occurs exclusively in the thoracic spine, causing slowly progressive myelopathy. Diagnosis is based on ventral displacement of the spinal cord in the thoracic spine. MRI is the technique of choice to exclude a posterior arachnoid cyst, the most common mistaken diagnosis, and to recognize a spinal cord herniation when an anterior dural defect is present. A case of ISCH is reported and a Literature review of this clinical entity often mis-diagnosed has been obtained.

Cardiac computed tomography imaging of a giant ascending aortic double chambers pseudoaneurysm infiltrating into the sternum

In this report we show an unusual case of a giant ascending aortic double chambers pseudoaneurysm eroding the sternum. The patient was an asymptomatic 22-year-old man who underwent CT Angiography with ECG gating and who previously underwent aortic valve replacement.

Influence of image reconstruction parameters on cardiovascular risk reclassification by Computed Tomography Coronary Artery Calcium Score

OBJECTIVE

To investigate the influence of different CT reconstruction parameters on coronary artery calcium scoring (CACS) values and reclassification of predicted cardiovascular (CV) risk.

METHODS

CACS was evaluated in 113 patients undergoing ECG-gated 64-slice CT. Reference CACS protocol included standard kernel filter (B35f) with slice thickness/increment of 3/1.5 mm, and field-of-view (FOV) of 150-180 mm. Influence of different image reconstruction algorithms (reconstructed slice thickness/increment 2.0/1.0-1.5/0.8-3.0/2.0-3.0/3.0 mm; slice kernel B30f-B45f; FOV 200-250 mm) on Agatston score was assessed by Bland-Altman plots and concordance correlation coefficient (CCC) analysis. Classification of CV risk was based on the Mayo Clinic classification.

RESULTS

Different CACS reconstruction parameters showed overall good accuracy and precision when compared with reference protocol. Protocols with larger FOV, thinner slices and sharper kernels were associated with significant CV risk reclassification. Use of kernel B45f showed a moderate positive correlation with reference CACS protocol (Agatston CCC = 0.67), and yielded significantly higher CACS values (p < .05). Reconstruction parameters using B30f or B45f kernels, 250 mm FOV, or slice thickness/increment of 2.0/1.0 mm or 1.5/0.8 mm, were associated with significant reclassification of CV risk (p < .05).

CONCLUSIONS

Kernel, FOV, slice thickness and increment are major determinants of accuracy and precision of CACS measurement. Despite high agreement and overall good correlation of different reconstruction protocols, thinner slices thickness and increment, and sharper kernels were associated with significant upward reclassification of CV risk. Larger FOV determined both upward and downward reclassification of CV risk.

Myocardial blood flow quantification for evaluation of coronary artery disease by computed tomography

During the last decade coronary computed tomography angiography (CTA) has become the preeminent non-invasive imaging modality to detect coronary artery disease (CAD) with high accuracy. However, CTA has a limited value in assessing the hemodynamic significance of a given stenosis due to a modest specificity and positive predictive value. In recent years, different CT techniques for detecting myocardial ischemia have emerged, such as CT-derived fractional flow reserve (FFR-CT), transluminal attenuation gradient (TAG), and myocardial CT perfusion (CTP) imaging. Myocardial CTP imaging can be performed with a single static scan during first pass of the contrast agent, with monoenergetic or dual-energy acquisition, or as a dynamic, time-resolved scan during stress by using coronary vasodilator agents (adenosine, dipyridamole, or regadenoson). A number of CTP techniques are available, which can assess myocardial perfusion in both a qualitative, semi-quantitative or quantitative manner. Once used primarily as research tools, these modalities are increasingly being used in routine clinical practice. All these techniques offer the substantial advantage of combining anatomical and functional evaluation of flow-limiting coronary stenosis in the same examination that would be beneficial for clinical decision-making. This review focuses on the state-of the-art and future trends of these evolving imaging modalities in the field of cardiology for the physiologic assessments of CAD.

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.

Lumen enhancement influences absolute noncalcific plaque density on multislice computed tomography coronary angiography: ex-vivo validation and in-vivo demonstration

AIM

The purpose of this study was to define the in-vitro and in-vivo effects of intracoronary enhancement on the absolute density values of coronary plaques during multislice computed tomography.

METHODS

We studied seven ex-vivo left coronary artery specimens surrounded by olive oil and filled with isotonic saline and four solutions with decreasing dilutions of contrast material: control (isotonic saline), 1/200, 1/80, 1/50, and 1/20. The multislice computed tomography protocol was: slice/collimation 32 x 2 x 0.6 mm and rotation time 330 ms. The attenuation (Hounsfield units) value of atherosclerotic plaques was measured for each dilution in lumen, plaque (noncalcified coronary wall thickening), calcium, and surrounding oil. In-vivo assessment was performed in 12 patients (nine men; mean age 58.7 +/- 9.9 years) who underwent two subsequent multislice computed tomography scans (arterial and delayed) after intravenous administration of a single bolus of contrast material. The attenuation values of lumen and plaques during arterial and delayed computed tomography were compared. The results were compared with one-way analysis of variance and correlated with Pearson's test.

RESULTS

Mean lumen (45 +/- 38-669 +/- 151 HU) and plaque (11 +/- 35-101 +/- 72 HU) attenuation differed significantly (P < 0.001) among the different dilutions. The attenuation of lumen and plaque of coronary plaques showed moderate correlation (r = 0.54, P < 0.001). The mean attenuation value in vivo for the arterial and delayed phase scans differed significantly (P < 0.001) for lumen (325 +/- 70 and 174 +/- 46 HU, respectively) and plaque (138 +/- 71 and 100 +/- 52 HU, respectively).

CONCLUSION

Coronary plaque attenuation values are significantly modified by differences in lumen contrast densities both ex vivo and in vivo. This should be taken into account when considering the distinction between lipid and fibrous plaques.

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.

Prevalence of coronary artery intramyocardial course in a large population of clinical patients detected by multislice computed tomography coronary angiography

BACKGROUND

Intramyocardial course, an inborn coronary anomaly, is defined as a segment of a major epicardial coronary artery that runs intramurally through the myocardium; in particular, we distinguish myocardial bridging, in which the vessel returns to an epicardial position after the muscle bridge, and intramyocardial course, which is described as a vessel running and ending in the myocardium.

PURPOSE

To evaluate the prevalence of myocardial bridging and intramyocardial course of coronary arteries as defined by multidetector computed tomography (MDCT) angiography.

MATERIAL AND METHODS

The study population consisted of 242 consecutive patients (211 men, 31 women; mean age 59+/-6 years) with atypical chest pain admitted to our hospital between December 2004 and September 2006. All MDCT examinations were performed using a 16-detector-row scanner (Aquilion 16 CFX; Toshiba Medical System, Tokyo, Japan). Patients with heart rate above 65 bpm received 50 mg atenolol orally for 3 days prior to the MDCT scan, or they increased their usual therapy with beta-blockers, in order to obtain a prescan heart rate <60 bpm. Curved multiplanar and 3D volume reconstructions were performed to explore coronary anatomy.

RESULTS

In 235 patients, the CT scan was successful and images were appropriate for evaluation. The prevalence of myocardial bridging and intramyocardial course of coronary arteries was 18.7% (47 cases) in our patient population. In 30 segments (63.8%), the vessels ran and ended in the myocardium. In the remaining 17 segments (36.2%), the vessels returned to an epicardial position after the muscle bridge. We found no difference in the prevalence of this inborn coronary anomaly when comparing different clinical characteristics of the study population (sex, age, body-mass index [BMI], etc.). The mean length of the subepicardial artery was 7 mm (range 5-12 mm), and the mean depth in the diastolic phase was 1.9 mm (range 1.2-2.3 mm). There was no significant difference of diameter in these segments between the different R-R phases examined.

CONCLUSION

Our study is in agreement with major angiographic literature reporting a prevalence of myocardial bridging and intramyocardial course between 0.5% and 33%. MDCT technology represents a useful, noninvasive imaging method to assess and evaluate the location, depth, and length of this anatomical variation.

Usefulness of multislice computed tomography to assess patency of coronary artery stents versus conventional coronary angiography

BACKGROUND

The aim of the present study was to assess the in-stent restenosis and occlusion of coronary artery stents by multislice computed tomography (MSCT) compared with conventional coronary angiography in patients with atypical chest pain and not practicable/non-conclusive stress test.

METHODS

Between December 2004 and March 2006, 81 patients were scheduled and of these 72 (65 men, mean age 61 years) with 90 stents underwent MSCT angiography using a 16-slice scanner, Toshiba Aquilion 16, 8-12 months after stent placement.

RESULTS

Of the 90 stents, 71 (79%) could be assessed and 19 (21%) were excluded because the image quality at the stent level was incompatible with diagnostic assessment. This results in sensitivity, specificity, and positive and negative predictive values for all assessable stents in the identification of occlusion and/or in-stent restenosis of 82, 96, 87, and 94%, respectively. When the 19 uninterpretable stents were included in the analysis, the diagnostic accuracy of MSCT in detecting in-stent restenosis and occlusion resulted in a sensitivity of 82%, specificity of 71%, positive predictive value of 40%, and negative predictive value of 94%.

CONCLUSION

The results of the study suggest that MSCT angiography is a useful method for evaluating patency/occlusion of large (>or=3 mm) coronary stents in symptomatic patients with atypical chest pain and concomitant not practicable/non-conclusive exercise or stress imaging test.

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.

[Anomalous origin of the circumflex artery from the right aortic sinus: assessment with conventional coronary angiography and multislice computed tomography]

Anomalous origin of the circumflex coronary artery from the right sinus of Valsalva is the most common coronary anomaly. This anomaly is thought to be of little clinical significance without the presence of severe narrowing of the vessel. A 43-year-old woman was referred to our institution for evaluation of atypical chest pain and equivocal results of the exercise stress test. We decided to perform multislice computed tomography coronary angiography before any other invasive studies. The scan was performed with a 16-row scanner (Aquilion 16 CFX, Toshiba Medical Systems, Tokyo, Japan) after intravenous administration of non-ionic contrast material. Scans revealed that the circumflex coronary artery originated from the right sinus of Valsalva; the initial course was retro-aortic until it reached its target in the atrioventricular groove; peripheral distribution of the circumflex coronary artery was then normal. The anomalous vessel presented a significant stenosis in its proximal tract. Coronary angiography confirmed that the origin of the circumflex coronary artery was from the right aortic sinus and the significant stenosis of the proximal portion of this vessel. This case confirms the full capability and accuracy of multislice computed tomography with the aid of post-processing techniques in the identification and evaluation of the ectopic origin of the left circumflex coronary artery from the right sinus of Valsalva, displaying accurately the origin, size, course, and relationship of the anomalous vessel with respect to surrounding structures.

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.

[Usefulness of coronary angiography with multidetector computed tomography in the evaluation of aorto-coronary bypass patency]

BACKGROUND

Coronary angiography is actually the gold standard to visualize coronary artery bypass graft patency and to detect bypass stenoses. However, it is an invasive examination that makes use of X-ray emission and it may lead to deleterious effects even at low dosage. Therefore, it is still needed a non-invasive examination with good diagnostic accuracy for the follow-up of patients with coronary artery bypass grafts. The aim of this study was to evaluate the diagnostic accuracy of a 40-row multidetector computed tomography scanner for the assessment of bypass surgery versus coronary angiography.

METHODS

Twenty-six consecutive patients (20 male, 6 female, mean age 65 years) and a total number of 68 coronary bypass grafts (25 arterial and 43 venous grafts, 111 anastomoses) were examined by 40-row multidetector computed tomography.

RESULTS

It was possible to analyze coronary artery bypass graft patency for every patient. At coronary angiography 23 patients showed bypass stenoses or occlusion: 19 of them were correctly diagnosed by computed tomography (sensitivity 84%, specificity 100%). In particular, computed tomography showed a sensitivity of 90% and a specificity of 100% for coronary artery bypass grafts, whereas it showed a sensitivity of 88% and a specificity of 94% for anastomoses.

CONCLUSIONS

On the basis of the results of our study, computed tomography is a valuable tool for assessing coronary artery bypass graft patency in patients with clinical suspect of coronary occlusion.

Forty-slice MDCT enteroclysis: evaluation after oral administration of isotonic solution in Crohn's disease

OBJECTIVE

The aim of this study was to evaluate the accuracy of multidetector computed tomography (MDCT) enteroclysis after oral hyperhydration with isotonic solution in detecting bowel wall alterations in patients with Crohn's disease.

MATERIALS AND METHODS

Twenty-eight patients with a diagnosis of Crohn's disease established by ileocolonoscopy and histology were enrolled in the study; 15 patients with negative ileocolonoscopy served as controls. In all cases, MDCT enteroclysis was performed after oral administration of 2,000 ml of isotonic solution and intravenous administration of N-butylscopolamine. Axial, isotropic multiplanar and volume-rendered reconstructions were used to evaluate bowel wall thickness, ulceration, contrast enhancement, extraparietal involvement and possible complications.

RESULTS

MDCT enteroclysis identified the typical signs of Crohn's disease in 26 patients (92.8%), with sensitivity of 92.8%, specificity of 100%, positive predictive value 100% and negative predictive value 75%.

CONCLUSIONS

MDCT enteroclysis after oral hyperhydration with isotonic solution showed a high level of accuracy in detecting small bowel changes in patients with Crohn's disease. It can be considered a safe and effective alternative to conventional radiography and small-bowel spiral computed tomography enema, especially in patients who refuse nasojejunal intubation.

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.

[Forty-slice multidetector computed tomography for non-invasive diagnostic approach to coronary artery disease]

BACKGROUND

Multidetector computed tomography coronary angiography (MDCT-CA) is a non-invasive technique that clearly shows coronary anatomy and correctly identifies plaque location and morphology. In this study we assessed diagnostic accuracy of MDCT-CA in detectiong significant stenosis in patients with clinically relevant coronary tree disease.

METHODS

. Fifty patients (38 males, 12 females, mean age 60.9 +/- 9.2 years) with atypical chest pain, stable or unstable angina pectoris, or non-ST-elevation myocardial infarction underwent MDCT-CA (Brilliance 40, Philips Medical Systems, Cleveland, OH, USA) within 3 days before diagnostic conventional coronary angiography. Inclusion criteria were sinus rhythm, heart rate <70 b/min, and ability to hold breath for more than 12 s. Exclusion criteria were known intolerance to contrast medium, serum creatinine >2 mg/dl, pregnancy, respiratory insufficiency, unstable clinical conditions, and severe heart failure. Beta-blockers were administered if heart rate was >70 b/min. To synchronize arrival of the contrast bolus (Iomeron 400, Bracco, Milan) in the coronary arteries with the start of the scan the bolus-tracking technique was used. Diagnostic accuracy was evaluated per segment, per vessel, and per patient.

RESULTS

Mean heart rate during examination was 61.9 +/- 6.2 b/min; 618 segments were evaluated. The assessment was impaired by respiratory artifacts only in 1 patient (2%). MDCT-CA showed good sensitivity, specificity, and positive and negative predictive values in detecting significant coronary artery stenosis (94, 94, 91, and 96% per segment; 91, 97, 95, and 92% per vessel; 100, 100, 100, and 100% per-patient, respectively).

CONCLUSIONS

Forty-slice MDCT-CA showed a good diagnostic capability in detecting significant coronary artery stenosis in patients referred to our institution for suspected or known significant coronary artery disease.

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.

Adjunctive value of CT coronary angiography in the diagnostic work-up of patients with typical angina pectoris

AIMS

To determine the adjunctive value of CT coronary angiography (CTCA) in the diagnostic work-up of patients with typical angina pectoris.

METHODS AND RESULTS

CTCA was performed in 62 consecutive patients (45 male, mean age 58.8 +/- 7.7 years) with typical angina undergoing diagnostic work-up including exercise-ECG and conventional coronary angiography. Only patients with sinus heart rhythm and ability to breath hold for 20 s were included. Patients with initial heart rates >/=70 beats/min received beta-blockers. We determined the post-test likelihood ratios, to detect or exclude patients with significant (>/=50% lumen diameter reduction) stenoses, of exercise-ECG and CTCA separately, and of CT performed after exercise-ECG testing. The prevalence of patients with significant coronary artery disease (CAD) was 74%. Positive and negative likelihood ratios for exercise-ECG were 2.3 [95% confidence interval (CI): 1.0-5.3] and 0.3 (95% CI: 0.2-0.7) and for CTCA 7.5 (95% CI: 2.1-27.1) and 0.0 (95% CI: 0.0-8), respectively. CTCA increased the post-test probability of significant CAD after a negative exercise-ECG from 58 to 91%, and after a positive exercise-ECG from 89 to 99%, while CT correctly identified patients without CAD (probability 0%).

CONCLUSION

Non-invasive CTCA is a potentially useful tool, in the diagnostic work-up of patients with typical angina pectoris, both to detect and to exclude significant CAD.

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.

Influence of convolution filtering on coronary plaque attenuation values: observations in an ex vivo model of multislice computed tomography coronary angiography

Attenuation variability (measured in Hounsfield Units, HU) of human coronary plaques using multislice computed tomography (MSCT) was evaluated in an ex vivo model with increasing convolution kernels. MSCT was performed in seven ex vivo left coronary arteries sunk into oil followingthe instillation of saline (1/∞) and a 1/50 solution of contrast material (400 mgI/ml iomeprol). Scan parameters were: slices/collimation, 16/0.75 mm; rotation time, 375 ms. Four convolution kernels were used: b30f-smooth, b36f-medium smooth, b46f-medium and b60f-sharp. An experienced radiologist scored for the presence of plaques and measured the attenuation in lumen, calcified and noncalcified plaques and the surrounding oil. The results were compared by the ANOVA test and correlated with Pearson’s test. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. The mean attenuation values were significantly different between the four filters (p < 0.0001) in each structure with both solutions. After clustering for the filter, all of the noncalcified plaque values (20.8 ± 39.1, 14.2 ± 35.8, 14.0 ± 32.0, 3.2 ± 32.4 HU with saline; 74.7 ± 66.6, 68.2 ± 63.3, 66.3 ± 66.5, 48.5 ± 60.0 HU in contrast solution) were significantly different, with the exception of the pair b36f–b46f, for which a moderate-high correlation was generally found. Improved SNRs and CNRs were achieved by b30f and b46f. The use of different convolution filters significantly modifief the attenuation values, while sharper filtering increased the calcified plaque attenuation and reduced the noncalcified plaque attenuation.

Incidentally discovered thyroid nodules: incidence, and greyscale and colour Doppler pattern in an adult population screened by real-time compound spatial sonography

PURPOSE

Our aim was to assess the incidence and ultrasound features of thyroid nodules in an adult population screened by means of high-resolution ultrasonography (HRUS) and to evaluate the contribution of real-time spatial compound sonography (CS) in terms of image quality.

MATERIALS AND METHODS

A total of 704 consecutive patients (400 women, 304 men) without thyroid disease underwent HRUS and CS examination of the thyroid gland. Number, size, location, echotexture and colour Doppler pattern of detected nodules were assessed. Two radiologists also assessed image quality of the two techniques.

RESULTS

Seven hundred and eleven thyroid nodules (size range 0.18-4.1 cm; mean: 1.1 cm) were detected in 233 subjects (33.1%). Of these, 416 (58.5%) were found in 143 women whereas 295 (41.5%) were detected in 90 men. In both genders, the number of detected nodules increased with age, with the highest prevalence in the seventh decade (p<0.001). There were 461/711 (64.9%) thyroid nodules that were hypoechoic, and 449/711 (63.1%) had peripheral vascularity only (p<0.001). Fine-needle aspiration (FNA) revealed no malignancies. CS was graded better than HRUS in 621/711 (87.3%) cases (p<0.001).

CONCLUSIONS

The prevalence of benign, small, hypoechoic thyroid nodules with peripheral vascularity was high in our series, thus suggesting a conservative approach. CS provided better image quality compared with HRUS.

Characterization of hypoechoic focal hepatic lesions in patients with fatty liver: diagnostic performance and confidence of contrast-enhanced ultrasound

The objective of this study was to assess the diagnostic performance of contrast-enhanced ultrasound (CEUS) to characterize hypoechoic focal hepatic lesions (HFHL) in fatty liver (FL). A study group of 105 patients with FL and 105 HFHLs (52 malignant and 53 benign) underwent CEUS after SonoVue administration. Two blinded readers independently reviewed baseline ultrasound (US) and CEUS scans and classified each lesion as malignant or benign on a five-point scale of confidence, and recorded whether further imaging work-up was needed. Sensitivity, specificity, areas under the receiver operating characteristic (ROC) curve (A (z)), and interobserver agreement were calculated. We observed that the diagnostic confidence improved after reviewing CEUS scans for both readers (A (z)=0.706 and 0.999 and A (z)=0.665 and 0.990 at baseline US and CEUS, respectively; p<0.0001). Inter-reader agreement increased (weighted k=0.748 at baseline US vs. 0.882 at CEUS). For both readers, after CEUS, the occurrence of correctly characterized lesions increased (from 27/105 [27.5%] to 94/105 [89.5%], and from 19/105 [18.1%] to 93/105 [88.6%], respectively; p<0.0001) and the need for further imaging decreased (from 93/105 [88.6%] to 26/105 [24.8%], and from 96/105 [91.4%] to 40/105 [38.1%], respectively; p<0.0001). We conclude that CEUS improves the diagnostic performance of radiologists in the characterization of HFHLs in FL and reduces the need for further imaging work-up.

Multislice Spiral Computed Tomography for the Evaluation of Stent Patency After Left Main Coronary Artery Stenting

Background— Surveillance conventional coronary angiography (CCA) is recommended 2 to 6 months after stent-supported left main coronary artery (LMCA) percutaneous coronary intervention due to the unpredictable occurrence of in-stent restenosis (ISR), with its attendant risks. Multislice computed tomography (MSCT) is a promising technique for noninvasive coronary evaluation. We evaluated the diagnostic performance of high-resolution MSCT to detect ISR after stenting of the LMCA.

Methods and Results— Seventy-four patients were prospectively identified from a consecutive patient population scheduled for follow-up CCA after LMCA stenting and underwent MSCT before CCA. Until August 2004, a 16-slice scanner was used (n=27), but we switched to the 64-slice scanner after that period (n=43). Patients with initial heart rates >65 bpm received β-blockers, which resulted in a mean periscan heart rate of 57±7 bpm. Among patients with technically adequate scans (n=70), MSCT correctly identified all patients with ISR (10 of 70) but misclassified 5 patients without ISR (false-positives). Overall, the accuracy of MSCT for detection of angiographic ISR was 93%. The sensitivity, specificity, and positive and negative predictive values were 100%, 91%, 67%, and 100%, respectively. When analysis was restricted to patients with stenting of the LMCA with or without extension into a single major side branch, accuracy was 98%. When both branches of the LMCA bifurcation were stented, accuracy was 83%. For the assessment of stent diameter and area, MSCT showed good correlation with intravascular ultrasound ( r =0.78 and 0.73, respectively). An intravascular ultrasound threshold value ≥1 mm was identified to reliably detect in-stent neointima hyperplasia with MSCT.

Conclusions— Current MSCT technology, in combination with optimal heart rate control, allows reliable noninvasive evaluation of selected patients after LMCA stenting. MSCT is safe to exclude left main ISR and may therefore be an acceptable first-line alternative to CCA.

Stercorary aseptic peritonitis due to diastatic caecal perforation: computed tomography findings

Caecal perforation is a complication secondary to colon obstruction. It may present with insidious clinical features and may be associated with chronic constipation. The event may become severe due to the peritonitic development. We present a case of caecal perforation associated with sub-occlusive carcinoma of the left colon and hypotonic colitis caused by chronic lavative abuse, demonstrated with Computed Tomography.

Prevalence of “high-riding” superior pericardial recesses on thin-section 16-MDCT scans

OBJECTIVE

The aim of this study was to evaluate the prevalence of "high-riding" superior pericardial recess (HRSPR) on thin-section (1 mm) 16-multidetector computed tomography (MDCT) scans.

MATERIALS AND METHODS

Three hundred and fourteen consecutive chest CT scans obtained with a thin-section 16 MDCT were retrospectively evaluated. The prevalence and characteristic of HRSPR were analyzed.

RESULTS

HRSPR was depicted in 21 patients (11 men and 10 women) (6.6%) who ranged in age from 28 to 72 years (mean age, 57 years). The extended recesses were rounded/oval shaped in five patients and triangular, spindle, half moon or irregular shaped in the other 16 patients.

CONCLUSION

Our data suggest as HRSPRs are more frequently and better depicted on thinsection MDCT scans, and this improves the capability to distinguish this superior extension of the superior aortic recess from abnormal findings such as lymphadenopathy, cystic lesions, and aortic dissection.

High iodine concentration contrast material for noninvasive multislice computed tomography coronary angiography: iopromide 370 versus iomeprol 400

OBJECTIVE

The objective of this study was to compare intracoronary attenuation on 16-row multislice computed tomography (16-MSCT) coronary angiography using 2 contrast materials (CM) with high iodine concentration.

MATERIAL AND METHODS

Forty consecutive patients (29 male, 11 female; mean age, 61+/-11 years) with suspected coronary artery disease were randomized to 2 groups to receive 100 mL of either iopromide 370 (group 1: Ultravist 370, 370 mg iodine/mL; Schering AG, Berlin, Germany) or iomeprol 400 (group 2: Iomeron 400, 400 mg iodine/mL; Bracco Imaging SpA, Milan, Italy). Both CM were administered at a rate of 4 mL/s. All patients underwent 16-MSCT coronary angiography (Sensation 16; Siemens, Germany) with collimation 16 x 0.75 mm and rotation time 375 ms. The attenuation in Hounsfield units (HU) achieved after each CM was determined at regions of interest (ROIs) placed at the origin of coronary arteries and on the ascending aorta, descending aorta, and pulmonary artery. Differences in mean attenuation in the coronary arteries and on the ascending aorta, descending aorta, and pulmonary artery were evaluated using Student t test.

RESULTS

The mean attenuation achieved at each anatomic site was consistently greater after iomeprol 400 than after iopromide 370. At the origin of coronary arteries, the mean attenuation after iomeprol 400 (340+/-53 HU) was greater (P<0.05) than that after iopromide 370 (313+/- 42 HU). Similar findings were noted for the mean attenuation in the ascending aorta, descending aorta, and pulmonary artery.

CONCLUSION

The intravenous administration of iomeprol 400 provides higher attenuation of the coronary arteries and of the great arteries of the thorax as compared with iopromide 370 using the same injection parameters.

Qualitative and quantitative evaluation of solitary thyroid nodules with contrast-enhanced ultrasound: initial results

To assess the feasibility of contrast-enhanced ultrasound (CEUS) of the thyroid gland and to evaluate the potential of this method for characterising solitary thyroid nodules.18 patients affected by solitary thyroid nodules (size range: 0.6 to 3.6 cm; mean: 1.8 cm) confirmed by surgery (nine papillary carcinomas, four follicular carcinomas, three hyperplasias, one follicular adenoma and one Plummer's adenoma) underwent pulse inversion US at low M.I. (0.06 to 0.08) after i.v. injection of a 2.4-mL bolus of SonoVue. Baseline echogenicity and the dynamic enhancement pattern of each nodule, in comparison with adjacent thyroid parenchyma, were assessed. Signal intensity values on grey-scale images were also calculated at baseline, 30 s, 60 s and 120 s after SonoVue administration. Following administration of SonoVue, malignant nodules showed absent (4 out of 13), faint dotted (4 out of 13) and diffuse (5 out of 13) contrast enhancement, in this last case inhomogeneous (4 out of 5 cases) or homogeneous (1 out of 5). Benign nodules showed diffuse contrast enhancement, both homogeneous (3 out of 5) and heterogeneous (2 out of 5). Quantitative data have confirmed subjective findings, but CEUS never modified precontrast analysis. CEUS of thyroid gland is a feasible technique, but overlapping findings seem to limit the potential of this technique in the characterization of thyroid nodules.

Coronary artery anomalies: incidence, pathophysiology, clinical relevance and role of diagnostic imaging

Conventional coronary angiography is the gold standard for the diagnosis of coronary artery anomalies. Coronary anomalies are relatively rare findings in patients undergoing conventional coronary angiography for suspected obstructive coronary artery disease. Recently, the increasing performance of diagnostic techniques, such as electron beam tomography (EBT), magnetic resonance (MR) and, more recently, multislice computed tomography (MSCT), has enabled their application to cardiac imaging. MSCT, in particular, has a prominent role in coronary imaging due to its spatial and temporal resolution and three-dimensional capabilities. We report the incidence and pathophysiology of coronary artery anomalies based on the capabilities of recent diagnostic tools with the aim of improving an accurate and noninvasive diagnostic approach.

Improving Diagnostic Accuracy of MDCT Coronary Angiography in Patients with Mild Heart Rhythm Irregularities Using ECG Editing

OBJECTIVE

The objective of our study was to compare diagnostic accuracy of MDCT coronary angiography in a population of patients with mild heart rhythm irregularities before and after editing the ECG.

SUBJECTS AND METHODS

Thirty-eight patients who underwent MDCT coronary angiography and conventional coronary angiography were enrolled in the study. The inclusion criterion was the presence of mild heart rhythm irregularities (i.e., premature beats; atrial fibrillation; mistriggering; or low heart rate, defined as 40 beats per minute or less) during the scan. All patients underwent MDCT with the following parameters: 16 detectors; collimation, 0.75 mm; gantry rotation time, 375 msec; 120 kV; and effective milliampere-second setting, 500-600. Images were reconstructed in two settings: before ECG editing and after ECG editing (i.e., arbitrary modification of temporal windows within the cardiac cycle at the site of mild heart rhythm irregularities). Data sets were scored for the presence of significant stenoses (> or = 50% lumen reduction) in coronary segments > or = 2 mm diameter. The results of the two groups were compared with a McNemar test, and a p value of less than 0.05 was considered significant.

RESULTS

The sensitivity, specificity, and negative and positive predictive values of MDCT coronary angiography for the detection of significant stenoses before and after ECG editing were 63% (41/65) and 92% (78/85); 97% (251/260) and 96% (305/317); 87% (62/71) and 87% (81/93); 91% (251/275) and 97% (305/313), respectively (p < 0.05). The proportion of nonassessable segments was reduced from 17% (70/416) before ECG editing to 2% (10/416) after.

CONCLUSION

ECG editing significantly improves diagnostic accuracy in a selected population of patients with mild heart rate irregularities.

Diagnostic accuracy of non-invasive 64-slice CT coronary angiography in patients with stable angina pectoris

Multislice computed tomography (CT) is an emerging technique for the non-invasive detection of coronary stenoses. While the diagnostic accuracy of 4-slice scanners was limited, 16-slice CT imagers showed promising results due to increased temporal and spatial resolution. These technical advances prompted us to evaluate the diagnostic performance of 64-slice CT coronary angiography in the detection of significant stenoses (defined as > or = 50% luminal diameter reduction) versus invasive quantitative coronary angiography (QCA). Thirty-five patients with stable angina pectoris underwent CT coronary angiography performed with a 64-slice scanner (gantry rotation time 330 ms, individual detector width 0.6 mm) prior to conventional coronary angiography. Patients with heart rates >70 beats/min received 100 mg metoprolol orally. One hundred millilitres of contrast agent with an iodine concentration of 400 mgl/ml were injected at a rate of 5 ml/s into the antecubital vein. The CT scan was triggered with the bolus tracking technique. The sensitivity, specificity and the positive and negative predictive values of 64-slice CT were 99%, 96%, 78% and 99%, respectively, on a per-segment basis. The values obtained on a per-patient basis were 100%, 90%, 96% and 100%, respectively. When referral to catheterisation is questionable, CT coronary angiography may identify subjects with normal angiograms and consistently decrease the number of unnecessary invasive procedures.

Non-invasive evaluation of coronary calcium

With the increasing diffusion of 4-row,16-row and 64-row multislice computed tomography scanners, widespread coronary calcium scoring has become possible in Europe. This relatively easy-to-perform test has a high sensitivity and low specificity for the detection of significant coronary artery stenosis, and may have an important role in the risk stratification for future coronary artery events in selected groups of patients, such as those immediately at risk. This study reviews the techniques available for coronary calcium scoring (electron beam tomography and multislice computed tomography) with their respective protocols, as well as their advantages and disadvantages. The methods for interpreting the results, the potential indications and the clinical applications of the techniques are also described.

High-Resolution Spiral Computed Tomography Coronary Angiography in Patients Referred for Diagnostic Conventional Coronary Angiography

Background— The diagnostic performance of the latest 64-slice CT scanner, with increased temporal (165 ms) and spatial (0.4 mm 3 ) resolution, to detect significant stenoses in the clinically relevant coronary tree is unknown.

Methods and Results— We studied 52 patients (34 men; mean age, 59.6±12.1 years) with atypical chest pain, stable or unstable angina pectoris, or non–ST-segment elevation myocardial infarction scheduled for diagnostic conventional coronary angiography. All patients had stable sinus rhythm. Patients with initial heart rates ≥70 bpm received β-blockers. Mean scan time was 13.3±0.9 seconds. The CT scans were analyzed by 2 observers unaware of the results of invasive coronary angiography, which was used as the standard of reference. All available coronary segments, regardless of size, were included in the evaluation. Lesions with ≥50 luminal narrowing were considered significant stenoses. Invasive coronary angiography demonstrated the absence of significant disease in 25% (13 of 52), single-vessel disease in 31% (16 of 52), and multivessel disease in 45% (23 of 52) of patients. One unsuccessful CT scan was classified as inconclusive. Ninety-four significant stenoses were present in the remaining 51 patients. Sensitivity, specificity, and positive and negative predictive values of CT for detecting significant stenoses on a segment-by-segment analysis were 99% (93 of 94; 95% CI, 94 to 99), 95% (601 of 631; 95% CI, 93 to 96), 76% (93 of 123; 95% CI, 67 to 89), and 99% (601 of 602; 95% CI, 99 to 100), respectively.

Conclusions— Noninvasive 64-slice CT coronary angiography accurately detects coronary stenoses in patients in sinus rhythm and presenting with atypical chest pain, stable or unstable angina, or non–ST-segment elevation myocardial infarction.

Non-invasive coronary angiography with 64-slice computed tomography

Multislice computed tomography is a rapidly emerging technique for the non-invasive visualization of coronary arteries. Over the past 5 years several scanner generation were introduced with a progressive improvement in the diagnostic accuracy in the detection of coronary artery stenosis in selected patients populations. The introduction of 64-slice technology has further improved the diagnostic performance. This technique is at the edge of clinical implementation and, even though large clinical trials are still missing, an increased demand for these type of studies is observed all over the world. We describe our experience of more than 1 year with 64-slice CT coronary angiography providing clues on reasonable clinical applications.

Influence of increasing convolution kernel filtering on plaque imaging with multislice CT using an ex-vivo model of coronary angiography

PURPOSE

To assess the variability in attenuation of coronary plaques with multislice CT-angiography (MSCT-CA) in an ex-vivo model with varying convolution kernels.

MATERIALS AND METHODS

MSCT-CA (Sensation 16, Siemens) was performed in three ex-vivo left coronary arteries after instillation of contrast material solution (Iomeprol 400 mgI/ml, dilution: 1/80). The specimens were placed in oil to simulate epicardial fat. Scan parameters: slices 16/0.75 mm, rotation time 375 ms, feed/rotation 3.0 mm, mAs 500, slice thickness 1 mm, and FOV 50 mm. Datasets were reconstructed using 4 different kernels (B30f-smooth, B36f-medium smooth, B46f-medium, and B60f-sharp). Each scan was scored for the presence of plaques. Once a plaque was detected, the operator performed attenuation measurements (HU) in coronary lumen, oil, calcified and soft plaque tissue using the same settings in all datasets. The results were compared with T-test and correlated with Pearson's test.

RESULTS

Overall, 464 measurements were performed. Significant differences (p<0.05) were found for the mean attenuation of lumen (B30f/B36f, B30f/B60f, B36f/B46f, B36f/B60f, and B46f/B60f), oil (B30f/B36f, B30f/B46f, B30f/B60f, B36f/B46f, and B46f/B60f), calcium (all kernels), and plaque (B30f/B36f, B30f/B46f, B30f/B60f, and B46f/B60f) using 4 different kernels. The attenuation values (mean+/-SD) within the lumen (246+/-6, 215+/-13, 248+/-5, and 270+/-7), oil (-123+/-3, -127+/-1, -121+/-6, and -127+/-4), calcified plaque tissue (703+/-334, 739+/-364, 817+/-381, and 1181+/-503), and soft plaque tissue (134+/-56, 111+/-49, 120+/-56, and 102+/-41) showed high correlation (p<0.001) when attenuation of all structures were compared in different kernels.

CONCLUSIONS

Use of sharper convolution kernels significantly increases the attenuation of the calcium within coronary plaques and reduces the attenuation of soft plaque tissue.

Multislice CT coronary angiography: how to do it and what is the current clinical performance?

The introduction of multislice computed tomography (MSCT) has allowed non-invasive coronary angiography. Although widely applied, extensive information on technical details of the technique is lacking. This survey offers detailed information on patient preparation, data acquisition, reconstruction and interpretation. In addition, a summary of the available studies using MSCT for non-invasive angiography is provided. Based on pooled analysis of direct comparisons between MSCT and invasive angiography, the weighted mean sensitivity and specificity of current 16-slice MSCT for the detection of coronary artery disease are 88% and 96%, respectively. At present, the technique is particularly well suited for reliable exclusion of coronary artery disease. It is important to emphasise that MSCT only provides anatomical images, visualising the presence of atherosclerosis; information on the haemodynamic significance of these lesions (i.e. ischaemia) cannot be derived.

Diagnostic accuracy of multislice computed tomography coronary angiography is improved at low heart rates

PURPOSE

Assess the effect of heart rate on diagnostic accuracy for the detection of significant coronary artery stenosis using 16-row multislice computed tomography (MSCT).

MATERIAL AND METHODS

About 120 patients (105 males; 59+/-11 years) with suspected coronary artery disease who underwent conventional coronary angiography (CA) and MSCT-CA were retrospectively enrolled for the study. Patients underwent a MSCT-CA (Sensation 16, Siemens, Germany), with the following protocol: collimation 16 x 0.75 mm, gantry rotation time 420 ms, feed/rotation 3.0 mm, kV 120, mAs 400-500. The protocol for contrast material administration was 100 ml of Iodixanol (Visipaque 320 mg l/ml, Amersham, UK) at 4 ml/s and the delay was defined with a bolus tracking technique. In all patients the mean heart rate (HR) during the scan was used as a criteria to divide the population in two groups of 60 patients each. In one group (Low HR) the 60 patients with lower heart rates, and in the other group (High HR) the patients with higher heart rates. In the two groups diagnostic accuracy (per coronary segment) for the detection of significant stenosis (>or=50% lumen reduction) was evaluated in vessels >or=2 mm of diameter using quantitative CA as reference standard. The difference in diagnostic accuracy were compared with a Chi(2) test and a p<0.05 was considered significant.

RESULTS

There was no significant difference between the two groups regarding age, gender, weight, mean intravascular attenuation, and calcium score. Overall 1,310 (652 for Low HR and 658 for High HR) segments with 219 (105 for Low HR and 114 for High HR) significant lesions were available for the analysis. The average heart rate was 52+/-4 HU and 63+/-5 HU for Low HR and High HR, respectively (p<0.001). The sensitivity and specificity were 92 and 96% for Low HR and 90 and 92% for High HR (p<0.05). There were 22 vs. 44 false positives, and 8 vs. 12 false negatives in the Low HR and High HR, respectively.

CONCLUSION

Increasing HR significantly deteriorates diagnostic accuracy in MSCT-CA.

Introduction to coronary imaging with 64-slice computed tomography

The aim of this article is to illustrate the main technical improvements in the last generation of 64-row CT scanners and the possible applications in coronary angiography. In particular, we describe the new physical components (X-ray tube-detectors system) and the general scan and reconstruction parameters. We then define the scan protocols for coronary angiography with the new generation of 64-row CT scanners to enable radiologists to perform a CT study on the basis of the diagnostic possibilities.