Ricardo Loureiro

Adenosine-induced stress myocardial perfusion imaging using dual-source cardiac computed tomography.

OBJECTIVES This study sought to determine the feasibility of performing a comprehensive cardiac computed tomographic (CT) examination incorporating stress and rest myocardial perfusion imaging together with coronary computed tomography angiography (CTA). BACKGROUND Although cardiac CT can identify coronary stenosis, very little data exist on the ability to detect stress-induced myocardial perfusion defects in humans. METHODS Thirty-four patients who had a nuclear stress test and invasive angiography were included in the study. Dual-source computed tomography (DSCT) was performed as follows: 1) stress CT: contrast-enhanced scan during adenosine infusion; 2) rest CT: contrast-enhanced scan using prospective triggering; and 3) delayed scan: acquired 7 min after rest CT. Images for CTA, computed tomography perfusion (CTP), and single-photon emission computed tomography (SPECT) were each read by 2 independent blinded readers. RESULTS The DSCT protocol was successfully completed for 33 of 34 subjects (average age 61.4 +/- 10.7 years; 82% male; body mass index 30.4 +/- 5 kg/m(2)) with an average radiation dose of 12.7 mSv. On a per-vessel basis, CTP alone had a sensitivity of 79% and a specificity of 80% for the detection of stenosis > or =50%, whereas SPECT myocardial perfusion imaging had a sensitivity of 67% and a specificity of 83%. For the detection of vessels with > or =50% stenosis with a corresponding SPECT perfusion abnormality, CTP had a sensitivity of 93% and a specificity of 74%. The CTA during adenosine infusion had a per-vessel sensitivity of 96%, specificity of 73%, and negative predictive value of 98% for the detection of stenosis > or =70%. CONCLUSIONS Adenosine stress CT can identify stress-induced myocardial perfusion defects with diagnostic accuracy comparable to SPECT, with similar radiation dose and with the advantage of providing information on coronary stenosis.

Assessment of nonstenotic coronary lesions by 64-slice multidetector computed tomography in comparison to intravascular ultrasound: Evaluation of nonculprit coronary lesions

BACKGROUND Multidetector computed tomography (MDCT) has recently emerged as a potential noninvasive alternative for high-resolution imaging of coronary arteries. OBJECTIVE In this study, we evaluated 64-slice MDCT for detection, quantification, and characterization of atherosclerotic plaque burden in nonculprit lesions. METHODS Data from 11 patients who underwent both MDCT and intravascular ultrasound (IVUS) for suspected coronary artery disease were collected, and a total of 17 coronary segments and 122 cross-sectional slices were analyzed by MDCT and IVUS. Coronary segments on MDCT were coregistered to IVUS, and each obtained slice was scored by 2 blinded observers for presence and type of plaque. Quantitative measurements included cross-sectional vessel area, lumen area, wall area, plaque volume, and plaque burden. Mean and standard deviation of Hounsfield units (HUs) were recorded for plaque when present. RESULTS Overall sensitivity for plaque detection was 95.0%, and specificity, positive predictive value, negative predictive value were 88.7%, 89.1%, and 94.8%, respectively. Spearmans correlation coefficients were 0.85, 0.75, 0.70, 0.89, and 0.54 for cross-sectional vessel area, lumen area, wall area, plaque volume, and plaque burden, respectively. The interobserver variability for plaque burden and plaque volume measurements between readers on 64-MDCT was high at 32.7% and 30.4%, respectively. Combined noncalcified plaque had a mean MDCT density significantly different from that of calcified plaque. Soft and fibrous plaques were not able to be distinguished based on their HU values. CONCLUSION Sixty-four-slice MDCT had good correlation with IVUS but with high interobserver variability. Plaque characterization remains a challenge with present MDCT technology.

Incremental value of myocardial perfusion over regional left ventricular function and coronary stenosis by cardiac CT for the detection of acute coronary syndromes in high-risk patients: A subgroup analysis of the ROMICAT trial

OBJECTIVES To determine the incremental benefit of assessing myocardial perfusion defects (MPD) for acute coronary syndromes (ACS) over coronary and functional assessment by rest cardiac computed tomography (CT) in patients with acute chest pain. BACKGROUND Assessment of myocardial perfusion is feasible with cardiac CT; however, the diagnostic value of this assessment in patients at risk for ACS has not been demonstrated. METHODS The study included patients who presented to the emergency department with acute chest pain, nonischemic initial electrocardiogram (ECG), and negative cardiac biomarkers but had clinical suspicion for ACS and underwent invasive coronary angiography (ICA). Results were blinded to caregivers and patients. CT data sets were independently assessed for the presence of coronary plaque and stenosis, regional left ventricular function, and myocardial perfusion deficits by 2 blinded observers. Coronary angiography was assessed for the presence of stenosis, TIMI myocardial perfusion grade, and corrected TIMI frame count. The endpoint was ACS during index hospitalization. RESULTS We analyzed data from 35 subjects (69% male, mean age 58 ± 9 years) of whom 22 (63%) had ACS. The sensitivity and specificity of MPD for ACS were 86% (95% CI: 64%-96%) and 62% (95% CI: 32%-85%), respectively. Combined, MPD and RWMA assessment resulted in specificity and sensitivity of 86% (95% CI: 64%-96%) and 85% (95% CI: 54%-97%), respectively. Adding MPD and RWMA to the assessment for significant stenosis (>50%) resulted in a higher sensitivity of 91% (69-98%) and specificity of 85% (54-97%) and a significantly increased overall diagnostic accuracy when compared with assessment for stenosis (AUC: 0.88 vs 0.79; respectively, P = 0.02). Diagnostic accuracy of CT was not associated with impaired CTFC >40 or myocardial TIMI perfusion grade < 3. CONCLUSIONS Assessment of myocardial perfusion and regional wall motion abnormalities may enhance the ability of CT to detect ACS in patients with acute chest pain.

Quantification of coronary stenosis by dual source computed tomography in patients: A comparative study with intravascular ultrasound and invasive angiography

OBJECTIVE To determine the accuracy of dual-source CT (DSCT) to quantify coronary stenosis compared to intravascular ultrasound (IVUS) and quantitative coronary angiography (QCA). METHODS 21 patients (23 vessels) were examined with DSCT, IVUS and invasive coronary angiography. Coronary minimal luminal diameter (MLD) and area (MLA) were measured in cross-sectional multi-planar reformatted images perpendicular to the vessel long-axis. The vessel cross-sectional area stenosis (MLA/CSA ratio) was calculated. DSCT results were compared with IVUS and QCA. RESULTS A good correlation between DSCT and IVUS was noted for diameter and area stenosis (r=0.69 and r=0.73), with an overestimation of MLD stenosis by DSCT (+9.1%) and an underestimation of MLA stenosis (-5.8%). For MLD and MLA, high correlation coefficients (r=0.78 and r=0.90, respectively) were found between DSCT and IVUS; and the bias was almost zero (-0.41 mm and +0.1mm(2), respectively). The correlation between DSCT and QCA was moderate (r=0.60) for MLD stenosis with minor overestimation by DSCT (+4.0%) and moderate (r=0.59) for MLD (bias, +0.01 mm). The cross-sectional area stenosis showed a moderate correlation (r=0.59) between DSCT and IVUS (+0.00). CONCLUSIONS DSCT allows accurate quantification of coronary stenosis as compared to IVUS. An excellent correlation was found for the MLA between DSCT and IVUS.

I Diretriz de Ressonância e Tomografia Cardiovascular da Sociedade Brasileira de Cardiologia Sumário Executivo

Cesar Augusto Mastrofrancisco Cattani, Dany Jasinowodolinsk, Fabiano Lucchesi, Fabio Berezowsky Rocha, Fatima Cristina Pedroti, Gilberto Szarf, Guilherme Urpia Monte, Iugiro Roberto Kuroki , Joalbo Andrade, Jose Rodrigues Parga Filho, Luis Claudio Correia, Luiz Francisco Avila, Marcelo Hadlich, Marcelo Zapparoli, Marcia Barbosa, Marcia Lima Mugnaini, Maria Helena Albernaz Siqueira, Marly Maria Uellendhal, Miguel Abraao Rosario Neto, Paulo R. Schwarzman, Raul Dias dos Santos Filho, Ricardo Loureiro, Roberto Kalil Filho, Robson de Macedo Vieira

Tuberculous Pseudoaneurysms of the Thoracic Aorta Comprehensive Evaluation by Cardiovascular Magnetic Resonance

A 16-year-old girl from an area in Brazil where tuberculosis was endemic was admitted because of recurrent chest pain, progressive dyspnea with exertion, and inability to climb more than 1 flight of stairs. She described fatigue, weight loss, night sweats, and adenopathy of her right axilla and neck during the previous 3 months. On admission she looked distressed, with a heart rate of 76 bpm and blood pressure of 110/55 mm Hg. The ECG demonstrated sinus rhythm with first-degree heart block (Figure 1). Figure 1. First-degree atrioventricular block on ECG. Her admission chest radiograph demonstrated cardiomegaly with pulmonary edema (Figure 2). Her cardiac enzymes were negative. The patient underwent cardiac evaluation with 2-dimensional echocardiography (not shown), which revealed an interatrial septal mass, mild tricuspid regurgitation, preserved systolic function, and moderate pericardial effusion. Figure 2. Chest radiograph showing cardiomegaly and pulmonary congestive features after admission to intensive care unit. For further characterization of the mass, cardiovascular …