A. Clemente

Low dose CT of the heart: a quantum leap into a new era of cardiovascular imaging

In 10 years, computed tomography coronary angiography (CTCA) has shifted from an investigational tool to clinical reality. Even though CT technologies are very advanced and widely available, a large body of evidence supporting the clinical role of CTCA is missing. The reason is that the speed of technological development has outpaced the ability of the scientific community to demonstrate the clinical utility of the technique. In addition, with each new CT generation, there is a further broadening of actual and potential applications. In this review we examine the state of the art on CTCA. In particular, we focus on issues concerning technological development, radiation dose, implementation, training and organisation.RiassuntoL’angiografia coronarica con tomografia computerizzata (CTCA) è passata in 10 anni da strumento di ricerca investigativa a strumento clinico di uso routinario. Anche se le tecnologie sono molto diffuse ed avanzate, la maggioranza delle evidenze non supportano ancora in modo forte l’utilizzo di questa metodica. La causa di questo risiede probabilmente nel fatto che la velocità dell’evoluzione tecnologica ha superato ampiamente la capacità del mondo scientifico di sviluppare dati che definiscano meglio il campo di utilizzo. A questo si aggiunge il fatto che ad ogni nuova generazione di apparecchi per la tomografia computerizzata (TC) le reali e potenziali applicazioni si espandono ulteriormente. Abbiamo revisionato lo stato dell’arte corrente sulla CTCA. In particolare, vengono approfonditi gli aspetti inerenti l’evoluzione tecnologica, la dose da radiazioni ionizzanti, l’implementazione, il training e l’organizzazione.

Plaque imaging with CT coronary angiography: Effect of intra-vascular attenuation on plaque type classification

AIM To assess the attenuation of non-calcified atherosclerotic coronary artery plaques with computed tomography coronary angiography (CTCA). METHODS Four hundred consecutive patients underwent CTCA (Group 1: 200 patients, Sensation 64 Cardiac, Siemens; Group 2: 200 patients, VCT GE Healthcare, with either Iomeprol 400 or Iodixanol 320, respectively) for suspected coronary artery disease (CAD). CTCA was performed using standard protocols. Image quality (score 0-3), plaque (within the accessible non-calcified component of each non-calcified/mixed plaque) and coronary lumen attenuation were measured. Data were compared on a per-segment/per-plaque basis. Plaques were classified as fibrous vs lipid rich based on different attenuation thresholds. A P < 0.05 was considered significant. RESULTS In 468 atherosclerotic plaques in Group 1 and 644 in Group 2, average image quality was 2.96 ± 0.19 in Group 1 and 2.93 ± 0.25 in Group 2 (P ≥ 0.05). Coronary lumen attenuation was 367 ± 85 Hounsfield units (HU) in Group 1 and 327 ± 73 HU in Group 2 (P < 0.05); non-calcified plaque attenuation was 48 ± 23 HU in Group 1 and 39 ± 21 HU in Group 2 (P < 0.05). Overall signal to noise ratio was 15.6 ± 4.7 in Group 1 and 21.2 ± 7.7 in Group 2 (P < 0.01). CONCLUSION Higher intra-vascular attenuation modifies significantly the attenuation of non-calcified coronary plaques. This results in a more difficult characterization between lipid rich vs fibrous type.

Prognostic value of CT coronary angiography: Focus on obstructive vs. nonobstructive disease and on the presence of left main disease

PurposeThe authors investigated the prognostic value of computed tomography coronary angiography (CTCA) for major adverse cardiac events (MACE) in patients with suspected or known coronary artery disease (CAD), with particular focus on left main (LM) disease and obstructive vs. nonobstructive disease.Materials and methodsA total of 727 consecutive patients (485 men, age 62±11years) with suspected (514; 70.1%) or known (213; 29.9%) CAD underwent CTCA. Patients were followed up for the occurrence of MACE (i.e. cardiac death, nonfatal myocardial infarction, unstable angina, percutaneous/surgical revascularisation).ResultsA total of 117 MACE [five cardiac deaths, 11 acute myocardial infarctions (AMI), five unstable angina, 86 percutaneous coronary interventions, ten coronary artery bypass grafts] occurred during a mean follow-up of 20 months. Severity and extension of CAD was associated with a progressively worse prognosis. The event rate was 0% among patients with normal coronary arteries at CTCA. The presence of LM disease was not associated with a worse prognosis either in patients with no history of CAD or in those with a history of CAD. At multivariate analysis, presence of obstructive CAD and diabetes were the only independent predictors of MACE.ConclusionsEvaluation of atherosclerotic burden by CTCA provides an independent prognostic value for prediction of MACE. Patients with normal CTCA findings have an excellent prognosis at follow-up.RiassuntoObiettivoL’obiettivo del nostro lavoro è valutare il valore prognostico dell’angiografia tramite tomografia computerizzata (TC) delle coronarie (CTCA) per eventi avversi cardiovascolari maggiori (MACE) in pazienti con malattia coronarica (CAD) sospetta o nota con particolare attenzione alla malattia del tronco comune (LM) ed al confronto tra malattia ostruttiva e non ostruttiva.Materiali e metodiSettecentoventisette pazienti consecutivi (485 maschi, età 62±11anni) con CAD sospetta (514; 70,1%) o nota (213; 29,9%) sono stati sottoposti a CTCA. I pazienti sono stati seguiti per i MACE (ad esempio, morte cardiaca, infarto miocardico non fatale [AMI], angina instabile, rivascolarizzazione).RisultatiSono stati osservati un totale di 117 MACE (5 morti cardiache, 11 AMI, 5 angine instabili, 96 rivascolarizzazioni) durante un follow-up medio di 20 mesi. La severità e l’estensione della CAD erano associate con una prognosi peggiore. Nei pazienti con coronarie normali alla CTCA non sono stati osservati eventi. La presenza di malattia del LM non era associata ad una prognosi peggiore nei pazienti senza e con storia di pregressa CAD. All’analisi multi-variata la presenza di CAD ostruttiva ed il diabete erano gli unici predittori indipendenti.ConclusioniLa valutazione del carico aterosclerotico alla CTCA ha un valore prognostico indipendente per i MACE. I pazienti con coronarie normali mostrano prognosi eccellente.

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.

Diagnostic accuracy of second-generation dual-source computed tomography coronary angiography with iterative reconstructions: a real-world experience

PurposeThe authors evaluated the diagnostic accuracy of second-generation dual-source (DSCT) computed tomography coronary angiography (CTCA) with iterative reconstructions for detecting obstructive coronary artery disease (CAD).Materials and methodsBetween June 2010 and February 2011, we enrolled 160 patients (85 men; mean age 61.2±11.6 years) with suspected CAD. All patients underwent CTCA and conventional coronary angiography (CCA). For the CTCA scan (Definition Flash, Siemens), we use prospective tube current modulation and 70-100 ml of iodinated contrast material (Iomeprol 400 mgI/ ml, Bracco). Data sets were reconstructed with iterative reconstruction algorithm (IRIS, Siemens). CTCA and CCA reports were used to evaluate accuracy using the threshold for significant stenosis at ≥50% and ≥70%, respectively.ResultsNo patient was excluded from the analysis. Heart rate was 64.3±11.9 bpm and radiation dose was 7.2±2.1 mSv. Disease prevalence was 30% (48/160). Sensitivity, specificity and positive and negative predictive values of CTCA in detecting significant stenosis were 90.1%, 93.3%, 53.2% and 99.1% (per segment), 97.5%, 91.2%, 61.4% and 99.6% (per vessel) and 100%, 83%, 71.6% and 100% (per patient), respectively. Positive and negative likelihood ratios at the per-patient level were 5.89 and 0.0, respectively.ConclusionsCTCA with second-generation DSCT in the real clinical world shows a diagnostic performance comparable with previously reported validation studies. The excellent negative predictive value and likelihood ratio make CTCA a first-line noninvasive method for diagnosing obstructive CAD.RiassuntoObiettivoScopo del presente lavoro è stato valutare l’accuratezza diagnostica dell’angiografia coronarica non invasiva con tomografia computerizzata (CTCA) a doppia sorgente (DSCT) di seconda generazione (64×2×2 strati) con ricostruzioni iterative, nell’individuazione della malattia coronarica (CAD) ostruttiva.Materiali e metodiTra giugno 2010 e febbraio 2011 sono stati arruolati nello studio 160 pazienti (85 maschi, età media 61,2±11,6 anni) con sospetta malattia coronarica. Tutti i pazienti sono stati sottoposti a CTCA e coronarografia convenzionale (CAG). Per la scansione CTCA è stata utilizzata la modulazione prospettica dell’amperaggio e 70–100 ml di mezzo di contrasto. I dataset sono stati ricostruiti con algoritmi iterativi. I referti della CTCA e della CAG sono utilizzati per la valutazione dell’accuratezza diagnostica utilizzano la definizione di stenosi ≥50% per la CTCA e ≥70% per la CAG.RisultatiNessun paziente è stato escluso dall’analisi. La frequenza cardiaca media è stata 64,3±11,9 battiti per minuto (bpm) e la dose media 7,2±2,1 mSv. La prevalenza di malattia dimostrata alla CAG era del 30% (48/160). Sensibilità, specificità, valore predittivo positivo e negativo della CTCA nella determinazione delle stenosi significative sono risultate del 90,1%, 93,3%, 53,2%, 99,1% (per segmento); 97,5%, 91,2%, 61,4%, 99,6% (per vaso); e 100%, 83%, 71,6%, 100% (per paziente). I likelihood ratio positivo e negativo nell’analisi per paziente sono risultati 5,89 e 0,0, rispettivamente.ConclusioniNel mondo reale, la CTCA mediante DSCT di seconda generazione mostra una performance diagnostica analoga agli studi di validazione pubblicati in letteratura. I valori ottimali di valore predittivo negativo ed i likelihood ratio collocano la CTCA tra le metodiche non invasive di prima istanza per la diagnosi di CAD ostruttiva.

The impact of training on diagnostic accuracy with computed tomography coronary angiography

Aim The aim of this study is to assess the image quality and diagnostic accuracy of computed tomography (CT) coronary angiography (CTCA) in different hospital settings with the same trained team. Materials and methods Four hundred patients were consecutively enrolled for CTCA in a large academic hospital (Group 1; Sensation 64 Cardiac, Siemens – Iomeprol 400, Bracco; 200 patients) and in a small local hospital (Group 2; VCT, GE Healthcare – Iodixanol 320, GE Healthcare; 200 patients). All patients were enrolled for suspected coronary artery disease (CAD) and patients with stents or who had previously undergone coronary bypass were excluded. Scan protocols (retrospectively ECG-gated; no dose reduction modulation applied) were performed in accordance with standards reported in the international literature with the best solution available on site. Image quality was assessed in each coronary segment with a 4-point Likert scale: 0, not assessable; 1, low; 2, average; 3, good. Diagnostic accuracy was calculated against conventional coronary angiography with a threshold of at least 50% for significant stenosis. Results There was no significant difference between demographics, BMI, prevalence of obstructive CAD, calcium score and heart rate between the two populations. The average image quality was 2.83 ± 0.37 for Group 1 and 2.86 ± 0.31 for Group 2 (P > 0.05). Per-segment sensitivity, specificity, positive and negative predictive values were 92.6% (87–95), 97.9% (97–98), 75.9% (69–81) and 99.5% (99–99), respectively, for Group 1, and 90.4% (85–93), 98.6% (98–99), 84.2% (78–88) and 99.2% (98–99), respectively, for Group 2 (P > 0.05). Conclusion There is no significant difference in image quality and diagnostic accuracy of CTCA when the investigation is performed by the same properly trained team. CTCA is a robust imaging modality for the detection of coronary artery stenosis.

Classification of noncalcified coronary atherosclerotic plaque components on CT coronary angiography: impact of vascular attenuation and density thresholds

PurposeThe authors assessed the effect of vascular attenuation and density thresholds on the classification of noncalcified plaque by computed tomography coronary angiography (CTCA).Materials and methodsThirty patients (men 25; age 59±8 years) with stable angina underwent arterial and delayed CTCA. At sites of atherosclerotic plaque, attenuation values (HU) were measured within the coronary lumen, noncalcified and calcified plaque material and the surrounding epicardial fat. Based on the measured CT attenuation values, coronary plaques were classified as lipid rich (attenuation value below the threshold) or fibrous (attenuation value above the threshold) using 30-HU, 50-HU and 70-HU density thresholds.ResultsOne hundred and sixty-seven plaques (117 mixed and 50 noncalcified) were detected and assessed. The attenuation values of mixed plaques were higher than those of exclusively noncalcified plaques in both the arterial (148.3±73.1 HU vs. 106.2±57.9 HU) and delayed (111.4±50.5 HU vs. 64.4±43.4 HU) phases (p<0.01). Using a 50-HU threshold, 12 (7.2%) plaques would be classified as lipid rich on arterial scan compared with 28 (17%) on the delayed-phase scan. Reclassification of these 16 (9.6%) plaques from fibrous to lipid rich involved 4/30 (13%) patients.ConclusionsClassification of coronary plaques as lipid rich or fibrous based on absolute CT attenuation values is significantly affected by vascular attenuation and density thresholds used for the definition.RiassuntoObiettivoScopo del presente lavoro è valutare l’effetto dell’attenuazione vascolare e delle soglie di densità sulla classificazione delle placche aterosclerotiche coronariche non calcifiche mediante angiografia coronarica con tomografia computerizzata (CTCA).Materiali e metodiTrenta pazienti (maschi 25; età 59±8 anni) con angina stabile sono stati sottoposti a CTCA in fase arteriosa e tardiva. Nei segmenti con aterosclerosi coronarica, è stata misurata l’attenuazione (HU) del lume coronarico, delle componenti calcifica e non calcifica delle placche aterosclerotiche e del tessuto adiposo epicardico adiacente. Sulla base delle attenuazioni misurate, le placche sono state classificate come lipidiche (valori di attenuazione al di sotto della soglia) o fibrose (valori di attenuazione al di sopra della soglia) utilizzando 30 HU, 50 HU e 70 HU come soglie di densità.RisultatiSono state rilevate e valutate 167 placche (117 miste e 50 non calcifiche). I valori di attenuazione della placche miste è risultato maggiore di quello delle placche esclusivamente non calcifiche, sia in fase arteriosa (148,3±73,1 HU vs. 106,2±57,9 HU) che in fase tardiva (111,4±50,5 HU vs. 64,4±43,4 HU; p<0,01). Utilizzando una soglia di 50 HU, 12 (7,2%) placche sarebbero state classificate come lipidiche nella fase arteriosa, contro 28 (17%) nella fase tardiva. La riclassificazione di queste 16 (9,6%) placche da fibrose a lipidiche è avvenuta in 4/30 (13%) pazienti.ConclusioniLa classificazione delle placche coronariche come lipidiche o fibrose sulla base dei valori assoluti di attenuazione è significativamente influenzata dall’attenuazione vascolare e dalle soglie di densità utilizzate per la definizione.

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.

Diagnostic accuracy of second-generation dual-source computed tomography coronary angiography with iterative reconstructions: a real-world experience@@@Accuratezza diagnostica dell’angiografia coronarica con tomografia computerizzata a doppia sorgente di seconda generazione con ricostruzioni iterative: valutazione nel mondo reale

PurposeThe authors evaluated the diagnostic accuracy of second-generation dual-source (DSCT) computed tomography coronary angiography (CTCA) with iterative reconstructions for detecting obstructive coronary artery disease (CAD).Materials and methodsBetween June 2010 and February 2011, we enrolled 160 patients (85 men; mean age 61.2±11.6 years) with suspected CAD. All patients underwent CTCA and conventional coronary angiography (CCA). For the CTCA scan (Definition Flash, Siemens), we use prospective tube current modulation and 70-100 ml of iodinated contrast material (Iomeprol 400 mgI/ ml, Bracco). Data sets were reconstructed with iterative reconstruction algorithm (IRIS, Siemens). CTCA and CCA reports were used to evaluate accuracy using the threshold for significant stenosis at ≥50% and ≥70%, respectively.ResultsNo patient was excluded from the analysis. Heart rate was 64.3±11.9 bpm and radiation dose was 7.2±2.1 mSv. Disease prevalence was 30% (48/160). Sensitivity, specificity and positive and negative predictive values of CTCA in detecting significant stenosis were 90.1%, 93.3%, 53.2% and 99.1% (per segment), 97.5%, 91.2%, 61.4% and 99.6% (per vessel) and 100%, 83%, 71.6% and 100% (per patient), respectively. Positive and negative likelihood ratios at the per-patient level were 5.89 and 0.0, respectively.ConclusionsCTCA with second-generation DSCT in the real clinical world shows a diagnostic performance comparable with previously reported validation studies. The excellent negative predictive value and likelihood ratio make CTCA a first-line noninvasive method for diagnosing obstructive CAD.RiassuntoObiettivoScopo del presente lavoro è stato valutare l’accuratezza diagnostica dell’angiografia coronarica non invasiva con tomografia computerizzata (CTCA) a doppia sorgente (DSCT) di seconda generazione (64×2×2 strati) con ricostruzioni iterative, nell’individuazione della malattia coronarica (CAD) ostruttiva.Materiali e metodiTra giugno 2010 e febbraio 2011 sono stati arruolati nello studio 160 pazienti (85 maschi, età media 61,2±11,6 anni) con sospetta malattia coronarica. Tutti i pazienti sono stati sottoposti a CTCA e coronarografia convenzionale (CAG). Per la scansione CTCA è stata utilizzata la modulazione prospettica dell’amperaggio e 70–100 ml di mezzo di contrasto. I dataset sono stati ricostruiti con algoritmi iterativi. I referti della CTCA e della CAG sono utilizzati per la valutazione dell’accuratezza diagnostica utilizzano la definizione di stenosi ≥50% per la CTCA e ≥70% per la CAG.RisultatiNessun paziente è stato escluso dall’analisi. La frequenza cardiaca media è stata 64,3±11,9 battiti per minuto (bpm) e la dose media 7,2±2,1 mSv. La prevalenza di malattia dimostrata alla CAG era del 30% (48/160). Sensibilità, specificità, valore predittivo positivo e negativo della CTCA nella determinazione delle stenosi significative sono risultate del 90,1%, 93,3%, 53,2%, 99,1% (per segmento); 97,5%, 91,2%, 61,4%, 99,6% (per vaso); e 100%, 83%, 71,6%, 100% (per paziente). I likelihood ratio positivo e negativo nell’analisi per paziente sono risultati 5,89 e 0,0, rispettivamente.ConclusioniNel mondo reale, la CTCA mediante DSCT di seconda generazione mostra una performance diagnostica analoga agli studi di validazione pubblicati in letteratura. I valori ottimali di valore predittivo negativo ed i likelihood ratio collocano la CTCA tra le metodiche non invasive di prima istanza per la diagnosi di CAD ostruttiva.

Accuratezza diagnostica dell'angiografia coronarica con tomografia computerizzata a doppia sorgente di seconda generazione con ricostruzioni iterative: Valutazione nel mondo reale

PurposeThe authors evaluated the diagnostic accuracy of second-generation dual-source (DSCT) computed tomography coronary angiography (CTCA) with iterative reconstructions for detecting obstructive coronary artery disease (CAD).Materials and methodsBetween June 2010 and February 2011, we enrolled 160 patients (85 men; mean age 61.2±11.6 years) with suspected CAD. All patients underwent CTCA and conventional coronary angiography (CCA). For the CTCA scan (Definition Flash, Siemens), we use prospective tube current modulation and 70-100 ml of iodinated contrast material (Iomeprol 400 mgI/ ml, Bracco). Data sets were reconstructed with iterative reconstruction algorithm (IRIS, Siemens). CTCA and CCA reports were used to evaluate accuracy using the threshold for significant stenosis at ≥50% and ≥70%, respectively.ResultsNo patient was excluded from the analysis. Heart rate was 64.3±11.9 bpm and radiation dose was 7.2±2.1 mSv. Disease prevalence was 30% (48/160). Sensitivity, specificity and positive and negative predictive values of CTCA in detecting significant stenosis were 90.1%, 93.3%, 53.2% and 99.1% (per segment), 97.5%, 91.2%, 61.4% and 99.6% (per vessel) and 100%, 83%, 71.6% and 100% (per patient), respectively. Positive and negative likelihood ratios at the per-patient level were 5.89 and 0.0, respectively.ConclusionsCTCA with second-generation DSCT in the real clinical world shows a diagnostic performance comparable with previously reported validation studies. The excellent negative predictive value and likelihood ratio make CTCA a first-line noninvasive method for diagnosing obstructive CAD.RiassuntoObiettivoScopo del presente lavoro è stato valutare l’accuratezza diagnostica dell’angiografia coronarica non invasiva con tomografia computerizzata (CTCA) a doppia sorgente (DSCT) di seconda generazione (64×2×2 strati) con ricostruzioni iterative, nell’individuazione della malattia coronarica (CAD) ostruttiva.Materiali e metodiTra giugno 2010 e febbraio 2011 sono stati arruolati nello studio 160 pazienti (85 maschi, età media 61,2±11,6 anni) con sospetta malattia coronarica. Tutti i pazienti sono stati sottoposti a CTCA e coronarografia convenzionale (CAG). Per la scansione CTCA è stata utilizzata la modulazione prospettica dell’amperaggio e 70–100 ml di mezzo di contrasto. I dataset sono stati ricostruiti con algoritmi iterativi. I referti della CTCA e della CAG sono utilizzati per la valutazione dell’accuratezza diagnostica utilizzano la definizione di stenosi ≥50% per la CTCA e ≥70% per la CAG.RisultatiNessun paziente è stato escluso dall’analisi. La frequenza cardiaca media è stata 64,3±11,9 battiti per minuto (bpm) e la dose media 7,2±2,1 mSv. La prevalenza di malattia dimostrata alla CAG era del 30% (48/160). Sensibilità, specificità, valore predittivo positivo e negativo della CTCA nella determinazione delle stenosi significative sono risultate del 90,1%, 93,3%, 53,2%, 99,1% (per segmento); 97,5%, 91,2%, 61,4%, 99,6% (per vaso); e 100%, 83%, 71,6%, 100% (per paziente). I likelihood ratio positivo e negativo nell’analisi per paziente sono risultati 5,89 e 0,0, rispettivamente.ConclusioniNel mondo reale, la CTCA mediante DSCT di seconda generazione mostra una performance diagnostica analoga agli studi di validazione pubblicati in letteratura. I valori ottimali di valore predittivo negativo ed i likelihood ratio collocano la CTCA tra le metodiche non invasive di prima istanza per la diagnosi di CAD ostruttiva.