Pancreatic cancer detection with a non-contrast MR protocol: is it reliable?

PURPOSE: The pancreatic cancer (PC) is the 4th leading cancer-related death, becoming the second one by 2030, with a 5 year survival rate of 8%. Considering its increased incidence in high-risk categories compared to the general population, we aimed to validate a non-contrast MR protocol, to detect PC in its earliest phase, which could be suitable as a screening tool in high-risk patients. MATERIALS AND METHODS: In this retrospective study, we selected 200 patients (> 40 years) from our radiological database, which performed upper abdominal MRI between 2012 and 2017. 100 were negative for pancreatic lesions and 100 positive for pancreatic lesion (< 30 mm). The latter group included: 40 PDAC (pancreatic adenocarcinoma), 42 BD-IPMN (Branch Duct- Intraductal Papillary Mucinous Neoplasm), 10 PNET(pancreatic neuroendocrine tumor), 4 SCN(serous cystic neoplasm), 3 IPS(intrapancreatic spleen), 1 MCN(mucinous cystic neoplasm). Three readers (R1, R2 and R3) with a high, medium and low experience, respectively, analysed, first, the non-contrast MR sequences (single-shot T2w breath-hold, GE T1w FS, DWI and 2D/3D MRCP), and then the standard MR protocol, independently, randomly and anonymously. Readers identified or excluded the presence of pancreatic lesion, in both reading sessions. These results were compared with the histopathological diagnosis, and then divided into 3 different classes of lesions: all lesions, pancreatic adenocarcinoma and solid lesion. Mcnemar's test was used to compare the results. The inter-observer agreement was determined according to the kappa statistic in both protocols, and then the inter-protocol agreement was calculated. RESULTS: The non-contrast MR protocol has reached statistical parameters values ranging between 83% in SE (sensitivity) by R3 and 99% in NPV (negative predictive value) by R1. The standard MR protocol has reported slight increasing statistical parameters compared to those of the proposed one. However, there are not significant statistical differences between the both protocols. The proposed non-contrast MR protocol has reported the highest NPVs in the PDAC group detection (R1: 99%, R2: 99%, R3: 98%). In all groups of lesions, the agreement between the two protocols was excellent for each Reader ranging from 96 to 98%. CONCLUSION: The proposed non-contrast MR protocol showed high PC detection values and a time execution ≤ 20 min. Therefore, it can be proposed as a screening tool in high-risk patients.

NETosis in Acute Thrombotic Disorders.

The release of extracellular traps by neutrophils (NETs) represents a novel active mechanism of cell death that has been recently implicated in the pathogenesis of thrombotic disorders. The aim of this study was to investigate the generation of NETs in different groups of patients with acute thrombotic events (ATEs) and to establish whether NETs markers can predict the risk of new cardiovascular events. We performed a case-control study of patients with ATE, including acute coronary syndrome (n = 60), cerebrovascular accident (n = 50), and venous thromboembolism (n = 55). Control subjects (n = 70) were identified among patients admitted for acute chest pain and in which a diagnosis of ATE was excluded. Serum levels of NET markers and neutrophil activation, such as myeloperoxidase (MPO)-DNA complexes, neutrophil gelatinase-associated lipocalin, polymorphonuclear neutrophil elastase, lactoferrin, and MPO, were measured in each patient. We found that circulating levels of MPO-DNA complexes were significantly increased in patients with ATE (p < 0.001) compared with controls and that this association remained significant even after fully adjustment for traditional risk factors (p = 0.001). A receiver operating characteristics analysis of circulating MPO-DNA complexes in discriminating between controls and patients with ATE showed a significant area under the curve of 0.76 (95% confidence interval: 0.69-0.82). After a median follow-up of 40.7 (± 13.8) months, 24 out of the 165 patients with ATE presented a new cardiovascular event and 18 patients died. None of the markers under investigation influenced survival or the incidence of new cardiovascular events. In conclusion, we found that increase of markers of NETosis can be observed in acute thrombotic conditions, occurring both on the arterial and venous site. Nevertheless, the level of neutrophil markers measured during the ATE is not predictive of future risk of mortality and cardiovascular events.

Biomarkers of Neutrophil Activation in Patients with Symptomatic Chronic Peripheral Artery Disease Predict Worse Cardiovascular Outcome.

Neutrophils play a role in cardiovascular (CV) disease. However, relatively scant evidence exists in the setting of peripheral artery disease (PAD). The aims of this study were to measure biomarkers of neutrophil activation in patients with symptomatic chronic PAD compared with healthy controls, to assess their association with PAD severity, and to evaluate their prognostic value in patients with PAD. The following circulating markers of neutrophil degranulation were tested: polymorphonuclear neutrophil (PMN) elastase, neutrophil gelatinase-associated lipocalin (NGAL), and myeloperoxidase (MPO). Neutrophil extracellular traps (NETs) were quantified by measuring circulating MPO-DNA complexes. Patients with PAD underwent a comprehensive series of vascular tests. The occurrence of 6-month major adverse CV (MACE) and limb events (MALE) was assessed. Overall, 110 participants were included, 66 of which had PAD. After adjustment for conventional CV risk factors, PMN-elastase (adjusted odds ratio [OR]: 1.008; 95% confidence interval [CI]: 1.002-1.015; p = 0.006), NGAL (adjusted OR: 1.045; 95%CI: 1.024-1.066; p < 0.001), and MPO (adjusted OR: 1.013; 95%CI: 1.001-1.024; p = 0.028) were significantly associated with PAD presence. PMN-elastase (adjusted hazard ratio [HR]: 1.010; 95%CI: 1.000-1.020; p = 0.040) and MPO (adjusted HR: 1.027; 95%CI: 1.004-1.051; p = 0.019) were predictive of 6-month MACE and/or MALE. MPO displayed fair prognostic performance on receiver operating characteristic (ROC) curve analyses, with an area under the curve (AUC) of 0.74 (95%CI: 0.56-0.91) and a sensitivity and specificity of 0.80 and 0.65, respectively, for a cut-off of 108.37 ng/mL. MPO-DNA showed a weak inverse correlation with transcutaneous oximetry (TcPO2) on proximal foot (adjusted ρ -0.287; p = 0.032). In conclusion, in patients with symptomatic chronic PAD, enhanced neutrophil activity may be associated with an increased risk of acute CV events, rather than correlate with disease severity. Further research is needed to clarify the role of neutrophils in PAD natural history.

Multidimensional 3-Month Follow-Up of Severe COVID-19: Airways beyond the Parenchyma in Symptomatic Patients.

SARS-CoV-2 may lead to a large spectrum of respiratory manifestations, including pulmonary sequelae. We conducted a single-center longitudinal study of survivors from severe COVID-19 cases who underwent a chest CT during hospitalization (CTH). Three months after being discharged, these patients were evaluated by a clinical examination, pulmonary function tests and a chest-CT scan (CTFU). Sixty-two patients were enrolled. At follow-up, 27% complained of exertional dyspnoea and 12% of cough. Dyspnoeic patients had a lower forced expiratory flow (FEF)25-75 (p = 0.015), while a CT scan (p = 0.016 showed that patients with cough had a higher extent of bronchiectasis. Lung volumes and diffusion of carbon monoxide (DLCO) at follow-up were lower in patients who had been invasively ventilated, which correlated inversely with the length of hospitalization and ground-glass extension at CTH. At follow-up, 14.5% of patients had a complete radiological resolution, while 85.5% presented persistence of ground-glass opacities, and 46.7% showed fibrotic-like alterations. Residual ground-glass at CTFU was related to the length of hospitalization (r = 0.48; p = 0.0002) and to the need for mechanical ventilation or high flow oxygen (p = 0.01) during the acute phase. In conclusion, although patients at three months from discharge showed functional impairment and radiological abnormalities, which correlated with a prolonged hospital stay and need for mechanical ventilation, the persistence of respiratory symptoms was related not to parenchymal but rather to airway sequelae.

Comparison of Triple-Rule-Out Prospectively ECG-triggered Systolic and Diastolic Acquisition Protocol in Patients With Acute Chest Pain.

PURPOSE: The purpose of this study was to compare image quality and coronary interpretability of triple-rule-out systolic and diastolic protocols in patients with acute chest pain. MATERIALS AND METHODS: From March 2016 to October 2017 the authors prospectively enrolled patients with undifferentiated acute chest pain, who were at low to intermediate cardiovascular risk. Those with heart rate >75 bpm underwent a systolic prospectively triggered acquisition (systolic triggering [ST]), and in those with ≤75 bpm, end-diastolic triggering (DT) was instead performed. Examinations were evaluated for coronary artery disease, aortic dissection, and pulmonary embolism. Image quality was assessed using a Likert scale. Coronary arteries interpretability was evaluated both on a per-vessel and a per segment basis. The occurrence of major adverse cardiovascular events was investigated. RESULTS: The final study population was 189 patients. Fifty-two patients (27.5%) underwent systolic acquisition and 137 (72.5%) underwent diastolic acquisition. No significant differences in overall image quality were observed between DT and ST groups (median score 5 [interquartile ranges 4 to 5] vs. 4 [interquartile ranges 4 to 5], P =0.074). Although both DT and ST protocols showed low percentages of noninterpretable coronary arteries on a per-vessel (1.5% and 6.7%, respectively) and per-segment analysis (1% and 4.7%, respectively), these percentages resulted significantly higher for ST groups ( P <0.001). Obstructive coronary stenosis was observed in 18 patients. Only one case of pulmonary embolism was diagnosed and no cases of aortic dissection were found in our population. No death or major adverse cardiovascular events were observed during follow-up among the 2 groups. CONCLUSIONS: Results showed that triple-rule-out computed tomography angiography is a reliable technique in patients with acute chest pain and that an ST acquisition protocol could be considered an alternative acquisition protocol in patients with higher heart rate, reaching a good image quality.

Clinical and angiographic outcomes of crossing techniques for coronary chronic total occlusions: the ISAR-CTO registry.

BACKGROUND: Clinical and angiographic outcomes following recanalisation of coronary chronic total occlusions (CTO) through contemporary dissection and re-entry techniques (DART) as opposed to intraplaque techniques remain controversial. AIMS: The aim of this study was to compare clinical and angiographic outcomes following subintimal and intraplaque CTO recanalisation. METHODS: A total of 454 consecutive patients undergoing successful CTO recanalisation (473 vessels) were included. Intraplaque techniques were used in 403 (85.2%) and DART in 70 (14.8%) vessels. Surveillance angiography was scheduled at 6-9 months and clinical follow-up was performed up to 12 months. RESULTS: There were no significant differences in terms of the cumulative incidence of MACE (p=0.908) or binary restenosis (p=0.320) between the two groups. There was no independent correlation between recanalisation technique and MACE occurrence or in-segment binary restenosis. Target lesion revascularisation (TLR) was performed in 60 (17.5%) and 12 (18.1%) (p=0.719) lesions, respectively. The occurrence of occlusive restenosis was low (7 [2.3%] vs 1 [1.6%]; p=0.824) and comparable between groups. CONCLUSIONS: Contemporary DART are associated with similar midterm clinical and angiographic outcomes compared to intraplaque recanalisation. The rate of occlusive restenosis was low and comparable in both groups. Regardless of recanalisation technique, the overall incidences of binary restenosis and TLR following CTO recanalisation remain higher than those reported for non-CTO PCI.

Prevention of Coronary Artery Disease-Related Heart Failure: The Role of Computed Tomography Scan.

During the past decade, coronary computed tomography angiography has emerged as the primary modality to noninvasively detect and rule out coronary artery disease. Therefore, this technique could play an important role in identifying patients at high risk of heart failure, considering the high prevalence of coronary artery disease in these patients. The latest technologies have also increased diagnostic accuracy, helping to close the gap with the other functional imaging modalities.

The Role of Imaging in COVID-19 Pneumonia Diagnosis and Management: Main Positions of the Experts, Key Imaging Features and Open Answers.

Lung imaging is widely involved in facing the coronavirus disease (COVID-19) pandemic. In fact, the COVID-19 infection may lead to a rapidly evolving and potentially fatal pneumonia. Moreover, computed tomography (CT) can be more sensitive than the COVID-19 reverse transcriptase-polymerase chain reaction test, especially at the beginning of the disease. Only patients with mild features consistent with COVID-19 infection, negative COVID-19 test, or positive COVID-19 test but at low risk for disease progression should avoid imaging. However, imaging becomes mandatory if respiratory symptoms worsen. A CT pattern classification has been designed to help both radiologists and clinicians. The typical pattern of COVID-19 is depicted by multifocal, bilateral, and peripheral ground-glass opacities (with or without consolidations or crazy paving) or findings of organizing pneumonia. Moreover, CT has demonstrated a prognostic role in patients with a diagnosis of COVID-19 pneumonia. Lung ultrasounds (LUS) are an emergent tool in the diagnosis of the disease. The adoption of LUS combined to chest X-rays in COVID-19 in pneumonia diagnosis is an interesting prospect that needs to be confirmed.

Deferred vs Immediate Stenting in Primary Percutaneous Coronary Intervention: A Collaborative Meta-analysis of Randomized Trials With Cardiac Magnetic Resonance Imaging Data.

BACKGROUND: The role of deferred vs immediate stenting during primary percutaneous coronary intervention (PCI) for patients with ST-segment elevation myocardial infarction (STEMI) remains controversial. METHODS: We undertook a collaborative meta-analysis of study-level data by searching electronic scientific databases for investigations of primary PCI patients randomized to deferred or immediate stenting and subsequent cardiac magnetic resonance imaging. Primary angiographic and imaging outcomes were slow/no-reflow and microvascular obstruction (MVO), respectively. Main secondary outcome was recurrent ischemia. RESULTS: Among 4 trials, a total of 1570 patients with STEMI were assigned to primary PCI with either deferred (n = 779) or immediate stenting (n = 791). Of these, 797 participants had analyzable cardiac magnetic resonance imaging examinations. Median clinical follow-up was 9 months. Patients treated with deferred stenting showed a lower risk of developing slow/no-reflow in the culprit vessel (risk ratio [RR], 0.54 [95% confidence interval (CI), 0.41-0.72]; P < 0.001), a similar risk for MVO (RR, 0.93 [95% CI, 0.76-1.14]; P = 0.51), and trended higher in the risk of recurrent ischemia (RR, 2.42 [95% CI, 0.88-6.63]; P = 0.09) compared with those treated with immediate stenting. The treatment effect for slow/no-reflow and MVO correlated with a thrombus score grade > 3 at the baseline angiography and with the total stent length implanted in the culprit artery. CONCLUSIONS: A strategy of deferred stenting during primary PCI improves angiographic but not imaging or clinical outcomes compared with immediate stenting. The potential lower risk for myocardial injury by deferred stenting in primary PCI patients with STEMI and high thrombus burden requires a confirmation in adequately sized randomized trials.

Drug-Coated Balloon Angioplasty for Femoropopliteal In-Stent Restenosis.

BACKGROUND: The optimal revascularization therapy for in-stent restenosis (ISR) of femoropopliteal arteries represents a matter of debate. We investigated the outcomes of patients treated with drug-coated balloon (DCB) angioplasty for ISR of femoropopliteal arteries. METHODS AND RESULTS: Patient-level data from 3 randomized trials of DCB angioplasty for ISR of femoropopliteal arteries were pooled. The primary outcome was target lesion revascularization. The main secondary outcome was recurrent ISR. Other outcomes of interest were ipsilateral amputation, death, Rutherford class improvement, and ankle-brachial index at follow-up. A total of 263 patients randomly assigned to DCB (n=133) or plain balloon angioplasty (n=130) were included in the analysis. After a follow-up of 12 months, patients treated with DCB angioplasty displayed a lower risk for target lesion revascularization (hazard ratio [95% CIs]: 0.25 [0.14-0.46]; P<0.001) and recurrent ISR (0.19 [0.10-0.35]; P<0.001) as compared with those treated with plain balloon angioplasty. There was no significant interaction between the treatment effect for target lesion revascularization and high-risk subgroups of patients such as those with diabetes mellitus, longer lesions, small vessels, moderate to severe underlying calcification, and occlusive pattern of ISR. DCB and plain balloon angioplasty were comparable with respect to other secondary outcomes. CONCLUSIONS: In case of femoropopliteal ISR, the percutaneous treatment with DCB angioplasty is associated with superior clinical and antirestenotic efficacy as compared with plain balloon angioplasty at 1-year follow-up, without attrition of efficacy in high-risk subgroups of patients. The long-term durability of DCB angioplasty in this setting remains to be further investigated.

An intriguing intracardiac mass in a woman with atrial fibrillation. Left atrial appendage (LAA) thrombus.

CLINICAL INTRODUCTION: A 74-year-old hypertensive woman presented with shortness of breath. There was no associated coughing, chest pain or fever. ECG identified atrial fibrillation with rapid ventricular response. A transoesophageal echocardiogram was scheduled to exclude thrombus before cardioversion (Figure 1A); however, an echogenic structure was seen (Figure 1B arrow, see online supplementary video 1) between the left atrium, the pulmonary artery and the aortic root. QUESTION: Which of the following is the most likely diagnosis? A. Aortic valve endocarditis with annular abscess. B. Left atrial appendage thrombus. C. Left atrial myxoma. D. Pulmonary embolism.

Cardiac-CT and Cardiac-MR examinations cost analysis, based on data of four Italian Centers.

PURPOSE: To establish the appropriate number of Cardiac-CT and Cardio-MR examinations, to determine an economically justified and sustainable investment in these two technologies, for an exclusive cardiologic use. MATERIALS AND METHODS: From July 2013 to July 2014, through a survey in four different Italian Departments of Radiology, data on the costs of Cardiac-CT and Cardiac-MR examinations were collected. For the evaluation of the costs of examinations, it was used an analytical accounting system, considering only the direct costs (consumables, health personnel work time, equipment amortization/maintenance) and other costs (utilities, services, etc.). Indirect costs (general costs) were not assessed. It was made a simulation, assuming an exclusive use of the CT and MR equipments for Cardiac-CT and Cardiac-MR examinations, calculating the annual number necessary to arrive at the Break Even Point (BEP: the point at which cost or expenses and revenue are equal). RESULTS: On the basis of the CT costs, in order to reach the BEP, performing only Cardiac-CT examinations, an average of 2641-2752 examinations/year is needed. The annual time commitment of the Medical Professional to ensure the number of examinations to reach the BEP is 2625-2750 h/year, equivalent to two Medical Doctors in a Cardiology Department. The recent Cardiac-CT Italian Registry, in the period January-June 2011, reports a number of examinations of 3455 patients in 47 different Centers, distributed throughout the whole national territory. With regard to MR, in order to reach the BEP, performing only Cardiac-MR examinations, an average of 2435-3123 examinations/year is needed. The annual time commitment of the Medical Professional to ensure the number of examinations to reach the BEP is 2437-3125 h/year, equivalent to two Medical Doctors in a Cardiology Department. The recent Cardiac-MR Italian Registry reports a number of examinations of 3776 patients in 40 Centers, distributed throughout the whole national territory. CONCLUSION: This research has shown that, only on the basis of costs, currently in Italy is anti-economic an exclusive use of CT or MR equipment for cardiac exams, unless it's not decided, regardless of the recent guidelines and clinical indications, to submit all patients with cardiac diseases (diseases of the coronary arteries and cardiomyopathies) to Cardiac-CT and Cardiac-MR examinations. This might likely to increase both the inappropriate examinations and either health spending and in the case of CT with important repercussions, in terms of radio-exposure, subject to forensic procedures.

Use of contrast agents in oncological imaging: magnetic resonance imaging.

Magnetic resonance plays a leading role in the management of oncology patients, providing superior contrast resolution and greater sensitivity compared with other techniques, which enables more accurate tumor identification, characterization and staging. Contrast agents are widely used in clinical magnetic resonance imaging; approximately 40-50% of clinical scans are contrast enhanced. Most contrast agents are based on the paramagnetic gadolinium ion Gd3+, which is chelated to avoid the toxic effects of free gadolinium. Multiple factors such as molecule structure, molecule concentration, dose, field strength and temperature determine the longitudinal and transverse relaxation rates (R1 and R2, respectively) and thus the T1- and T2-relaxivities of these chelates. These T1- and T2-relaxivities, together with their pharmacokinetic properties (i.e. distribution and concentration in the area of interest), determine the radiologic efficacy of the gadolinium-based contrast agents.

Imaging for oncologic staging and follow-up: review of current methods and novel approaches.

PURPOSE: To review the current radiological methodologies and guidelines for staging and followup in oncology, and to give a perspective based on the available new technologies in oncologic radiology. MATERIALS AND METHODS: The literature on cancer radiologic quantification in diagnostic phase and follow-up has been reviewed. The main concepts and guidelines (official and non-official) have been extracted taking into account the period of publication and the available technology. The current World Health Organization (WHO) and Response Evaluation Criteria In Solid Tumors (RECIST) guidelines have been critically evaluated on the basis of technical literature on quantitative radiology applied to oncology. Pitfalls of previous and current guidelines have been exploited on the basis of currently available techniques for quantification. RESULTS: Errors due to operator, scanner, software, and measurement technique inconsistency are all together far more relevant than the recognized thresholds applied for detecting therapeutic response. For this reason the volumetric assessment of cancer disease should be introduced. CONCLUSION: Even though the technical constraints are still prominent in the clinical practice, the design of clinical trials should be planned taking into account these new volumetric quantitative techniques.

Tips and tricks in Multislice CT coronary angiography.

The introduction of the multislice computed tomography (MSCT) scanners and their application to coronary imaging has created a new clinical imaging field. Even though MSCT coronary angiography has been reported to be able to detect significant stenoses with very high diagnostic accuracy, the clinical implementation is still difficult and the users are having difficulties in reproducing the results in literature, partly due to the limited experience in the field of coronary MSCT. Several details can be overlooked so that diagnostic mistakes are possible. In this paper we tried to collect a series of technical "tips and tricks" that might improve the quality of coronary imaging in the clinical practice.

Prevalence of anatomical variants and coronary anomalies in 543 consecutive patients studied with 64-slice CT coronary angiography.

The aim of our study was to assess the prevalence of variants and anomalies of the coronary artery tree in patients who underwent 64-slice computed tomography coronary angiography (CT-CA) for suspected or known coronary artery disease. A total of 543 patients (389 male, mean age 60.5 +/- 10.9) were reviewed for coronary artery variants and anomalies including post-processing tools. The majority of segments were identified according to the American Heart Association scheme. The coronary dominance pattern results were: right, 86.6%; left, 9.2%; balanced, 4.2%. The left main coronary artery had a mean length of 112 +/- 55 mm. The intermediate branch was present in the 21.9%. A variable number of diagonals (one, 25%; two, 49.7%; more than two, 24%; none, 1.3%) and marginals (one, 35.2%; two, 46.2%; more than two, 18%; none, 0.6%) was visualized. Furthermore, CT-CA may visualize smaller branches such as the conus branch artery (98%), the sinus node artery (91.6%), and the septal branches (93%). Single or associated coronary anomalies occurred in 18.4% of the patients, with the following distribution: 43 anomalies of origin and course, 68 intrinsic anomalies (59 myocardial bridging, nine aneurisms), three fistulas. In conclusion, 64-slice CT-CA provides optimal visualization of the variable and complex anatomy of coronary arteries because of the improved isotropic spatial resolution and flexible post-processing tool.

Influence of intra-coronary enhancement on diagnostic accuracy with 64-slice CT coronary angiography.

We assessed the effect of intra-coronary attenuation on diagnostic accuracy using 64-slice computed tomography coronary angiography (CT-CA). We enrolled 170 patients with suspected coronary artery disease who underwent conventional coronary angiography (CA) and 64-slice CT-CA (100 ml of Iomeprol 400 mg I/ml at 4 ml/s). The study population was divided into two groups (85 patients each based on median attenuation of 326 HU) based on mean arterial attenuation; group 1 with low attenuation and group 2 with high attenuation. Diagnostic accuracy for the detection of significant coronary artery stenosis was determined for both groups using CA as reference standard. Overall, 163 significant stenoses were detected in 1,030 assessable coronary artery segments in group 1 compared with 160 significant stenoses in 1,020 assessable segments in group 2. The average intra-coronary attenuation was significantly (P < 0.05) higher for group 2 (388 +/- 46 HU) compared with group 1 (291 +/- 33 HU). The corresponding sensitivity and specificity values for detection of significant coronary artery stenosis were higher for group 2 (96.3% and 97.6%, respectively) than for group 1 (82.8% and 93.2%, respectively) and were more marked in distal coronary segments than in proximal segments. Higher intra-coronary attenuation on CT-CA results in greater diagnostic accuracy for detection of coronary artery stenosis.

Evaluation of coronary atherosclerosis by multislice computed tomography in patients with acute myocardial infarction and without significant coronary artery stenosis: a comparative study with quantitative coronary angiography.

BACKGROUND: It is known that 9% to 31% of women and 4% to 14% of men with acute myocardial infarction have normal coronary arteries or nonsignificant coronary disease at angiography. These patients represent a diagnostic and therapeutic challenge. Multislice computed tomography (CT) can noninvasively identify the presence of coronary plaques even in the absence of significant coronary artery stenosis. This study evaluated the role of 64-slice CT, in comparison with coronary angiography, in detecting and characterizing coronary atherosclerosis in patients with acute myocardial infarction without significant coronary artery stenosis. METHODS AND RESULTS: Thirty consecutive patients with acute myocardial infarction but without significant coronary stenosis at coronary angiography underwent 64-slice CT. All coronary segments were quantitatively analyzed by means of coronary angiography (CA-QCA) and 64-slice CT (CT-QCA). Forty-seven (10.4%) of the 450 coronary segments were not evaluable by CT. The mean proximal reference diameters at CT-QCA and CA-QCA were, respectively, 2.88+/-0.75 mm and 2.65+/-0.9 mm; the overall correlation between CT-QCA and CA-QCA for quantification of reference diameter was r(s)=0.77; P<0.001. The mean percent stenosis was 14.4+/-8.0% at CT-QCA and 4.0+/-11.0% at CA-QCA and the correlation was r(s)=0.11; P=0.03. Overall CT-QCA showed the presence of 50 plaques, of which only 11 were detected by CA-QCA. CT-QCA identified 25 plaques in infarct-related coronary arteries. Positive remodeling was present in 38 of the 50 plaques (76%), with a higher prevalence in the coronary plaques not visualized by CA-QCA (82.1% versus 54.5%). CONCLUSIONS: CT-QCA correlates well with CA-QCA in terms of coronary reference diameter analysis, but not stenosis quantification. Multislice CT can detect coronary atherosclerotic plaques in segments of nonstenotic coronary arteries that are underestimated by CA and may have an incremental diagnostic value for the diagnosis of acute myocardial infarction in patients without significant coronary stenosis at CA.