Roberto Malago

Learning Curve for Coronary CT Angiography: What Constitutes Sufficient Training?

PURPOSE To prospectively evaluate the effect of experience with coronary computed tomographic (CT) angiography on the capability to detect coronary stenoses of 50% or more. MATERIALS AND METHODS The institutional review board approved the study protocol. All patients gave consent to undergo CT angiography before conventional coronary angiography after being informed of the additional radiation dose. They also consented to the use of their data for future research. Three radiologists and one cardiologist inexperienced with coronary CT angiography attended this institutions cardiac CT unit for a 1-year fellowship. Fellows were involved in the acquisition and reading of 12-15 coronary CT angiograms per week (about 600 per year). To assess the progression in diagnostic performance, fellows (readers) independently read 50 CT angiographic test cases in patients who also underwent conventional coronary angiography. Cases were repeatedly assigned in random order at baseline and at 4, 8, 26, and 52 weeks. The same cases were examined by two experts in consensus. Sensitivity, specificity, and diagnostic odds ratios (DORs) were calculated and compared with conventional coronary angiography as the reference standard. RESULTS Respective reader ranges for sensitivity, specificity, and DOR were 33%-72%, 70%-94%, and 3.8-8.1 at baseline; 43%-80%, 71%-88%, and 8.8-15.2 after 6 months; and 66%-75%, 87%-92%, and 14.7-25.8 after 1 year. For expert physicians, respective results were 95%, 93%, and 255.9. Between baseline and 6 months, readers 1-3 showed nonsignificantly improved sensitivities, while specificities remained similar. Reader 4 showed significantly improved specificity, while sensitivity remained similar; all readers nonsignificantly improved DORs. Between baseline and 1 year: readers 1 and 2 significantly improved sensitivity but not specificity; reader 4 significantly improved specificity but not sensitivity; readers 1, 2, and 4 improved DOR significantly; reader 3 nonsignificantly improved sensitivity, specificity, and DOR. CONCLUSION Increasing experience with coronary CT angiography improved the diagnostic performance of inexperienced physicians. However, acquiring expertise in coronary CT angiography was slow and may take more than 1 year.

Contrast-enhanced ultrasonography better identifies pancreatic tumor vascularization than helical CT.

Background: Contrast-enhanced ultrasonography (CEUS) is a recently introduced field of ultrasonography (US). To assess the ability of CEUS to identify the vascularization of solid pancreatic tumors in comparison to helical CT. Methods: Forty-two resected pancreatic tumors, found at US, were studied with CEUS and helical CT. The tumor enhancement at CEUS was scored in comparison to the baseline aspect of the lesion and/or the extralesional pancreatic parenchyma together with the adjacent vessels during the dynamic study. All the lesions underwent pathological examination using H&E stains and CD34 markers with an evaluation of the microvessel density (MVD). The correlation of CEUS and helical CT with the MVD of the lesions was established with Spearman’s test. Results: The correlation of CEUS with the MVD of the lesions was significantly superior (Rs = 0.914; p < 0.0001) to that of helical CT (Rs = 0.635; p < 0.0001). Conclusions: CEUS is better than helical CT in the identification of the vascularization of solid pancreatic tumors. CEUS, when the pancreatic gland is optimally visualized, should be therefore considered a complementary imaging modality in the characterization of pancreatic tumors. CEUS can be a valid onco-imaging modality for quantifying tumoral vascularization in a noninvasive and accurate way.

Comparison of contrast-enhanced sonography and MRI in displaying anatomic features of cystic pancreatic masses.

OBJECTIVE The purpose of this study was to compare the accuracy rates of unenhanced sonography, contrast-enhanced sonography, and MRI in displaying the anatomic features of cystic pancreatic masses larger than 1.5 mm in diameter. MATERIALS AND METHODS Unenhanced and contrast-enhanced sonographic and MRI examinations of 33 patients who underwent resection of a cystic pancreatic mass were retrospectively reviewed. Two radiologists blinded to the final histologic diagnosis reviewed the images, specifically assessing the presence of intralesional mural nodules and septa. Sensitivity, specificity, positive and negative predictive values, and accuracy were calculated on the basis of correlation with surgical findings. Results of unenhanced sonography, contrast-enhanced sonography, and MRI were compared by McNemar test. Correlation of unenhanced and contrast-enhanced sonographic versus pathologic results was established with Spearmans test. Interobserver variability was determined. RESULTS Contrast-enhanced sonography correctly depicted intralesional septa in 14 of 15 lesions (sensitivity, 93.3%; specificity, 88.8%; positive predictive value, 87.5%; negative predictive value, 94.1%; accuracy, 90.9%) and nodules in six of eight lesions (sensitivity, 75%; specificity, 96%; positive predictive value, 85.7%; negative predictive value, 92.3%; accuracy, 90.9%). MRI correctly depicted intralesional septa in 14 of 15 lesions (sensitivity, 93.3%; specificity, 61.1%; positive predictive value, 66.6%; negative predictive value, 91.6%; accuracy, 75.7%) and nodules in seven of eight lesions (sensitivity, 87.5%; specificity, 80%; positive predictive value, 58.3%; negative predictive value, 95.2%; accuracy, 81.8%). The difference between the diagnostic accuracy of contrast-enhanced sonography and that of MRI was not significant (p = 0.05, McNemar test) in the identification of septa and nodules. The correlation between contrast-enhanced sonographic findings and pathologic results (Rs = 0.93; p < 0.001) was significantly better than that between sonographic and pathologic results (Rs = 0.52; p < 0.0001). Interobserver agreement had a kappa value of 0.86-0.94. CONCLUSION Contrast-enhanced sonography compares favorably with MRI in displaying the anatomic features of cystic pancreatic masses seen on transabdominal sonography.

Contrast-enhanced sonography of nonfunctioning pancreatic neuroendocrine tumors.

OBJECTIVE Diagnosis of malignancy and prognostic assessment continue to be problems in the management of nonfunctioning pancreatic endocrine tumors. Histologic examination is the reference standard. The aim of our study was to compare B-mode and contrast-enhanced sonographic findings regarding nonfunctioning pancreatic endocrine tumors. Signs of malignancy, such as Ki67 index and presence of hepatic metastasis, were considered. MATERIALS AND METHODS We retrospectively reviewed the cases of 38 consecutively registered patients with nonfunctioning pancreatic endocrine tumors evaluated with B-mode and contrast-enhanced sonography and resected. At contrast-enhanced sonography all lesions were divided into hypovascular lesions and isovascular or hypervascular lesions. On the basis of homogeneity of enhancement, lesions were classified as homogeneous and inhomogeneous. During the late phase of contrast enhancement, all solid focal hypoechoic liver lesions detected at contrast-enhanced sonography were considered hepatic metastatic lesions. Among pathologic data, grading, mitotic index, and Ki67 index were evaluated. Spearmans test was used to compare contrast-enhanced sonographic enhancement pattern with pathologic grade. RESULTS In the arterial phase, 24 of 38 nonfunctioning pancreatic endocrine tumors (63.1%) were hypervascular, seven (18.4%) were isovascular, and seven (18.4%) were hypovascular. Positive correlation was found between contrast-enhanced sonographic findings and Ki67 index (r(s) = 0.62; p < 0.0001). The difference between contrast-enhanced and B-mode sonography in the diagnosis of nonfunctioning pancreatic endocrine tumors was statistically significant (p < 0.05). Use of contrast-enhanced sonography increased diagnostic confidence in the detection of hepatic metastasis. The areas under the receiver operating characteristic curves were 0.916 for B-mode sonography and 1.000 for contrast-enhanced sonography (p < 0.05). There was moderate positive correlation between contrast-enhanced sonographic enhancement pattern and the presence of hepatic metastasis at diagnosis (r(s) = 0.46; p = 0.004) and between Ki67 index and the presence of hepatic metastasis (r(s) = 0.48; p = 0.0022). CONCLUSION The contrast-enhanced sonographic enhancement pattern of nonfunctioning pancreatic endocrine tumors has a positive correlation with Ki67 index, which is considered the most reliable independent predictor of the presence of malignancy.

Assessment of Crohn’s disease activity in the small bowel with MR-enteroclysis: clinico-radiological correlations

BackgroundThe aim of our study was to evaluate the accuracy of magnetic resonance imaging (MRI) in evaluating Crohn’s disease (CD) activity compared to clinical/laboratory data.MethodsNinety-three consecutive patients with CD were prospectively studied by MR imaging, before and after Gadolinium chelates administration, with use of a biphasic endoluminal contrast agent. MR image analysis included: number of lesions, presence/absence of bowel stenosis, upstream bowel dilation, wall thickness, presence of enhancement, enhancement pattern, presence/absence of comb sign, lymph nodes, and perianal fistulas/abscesses. Clinical evaluation was performed by means of Harvey & Bradshaw Index. Acute-phase reactants were considered standard of reference to monitor biological activity (BA). MR imaging findings were compared with clinical and laboratory data.ResultsMR image analysis detected: In 96 exams multiple lesions in 16, 1 in 50; no lesions in 30; stenosis in 52; dilatation in 28; wall thickening in 59; significant enhancement in 57; layered pattern in 50; comb sign in 37; enlarged lymph nodes in 16; fibro-fatty proliferation in 40; fistulas in 9.ConclusionsMRI is able to depict morphological changes and is helpful in assessing Crohn’s inflammatory disease.

Diagnostic accuracy of 64-slice computed tomography coronary angiography in patients with low-to-intermediate risk

PurposeOur aim was to evaluate the diagnostic accuracy of 64-slice computed tomography coronary angiography (MSCT-CA) for detecting significant stenosis (≥50% lumen reduction) in a population of patients at low to intermediate risk.Materials and methodsWe studied 72 patients (38 men, 34 women, mean age 53.9±8.0 years) with atypical or typical chest pain and stratified in the low-to intermediate risk category. MSCT-CA (Sensation 64 Cardiac, Siemens, Germany) was performed after IV administration of 100 ml of iodinated contrast material (Iomeprol 400 mgI/ml, Bracco, Italy). Two observers, blinded to the results of conventional coronary angiography (CAG), assessed the MSCT-CA scans in consensus. Diagnostic accuracy for detecting significant stenosis was calculated.ResultsCAG demonstrated the absence of significant disease in 70.1% of patients (51/72). No patient was excluded from MSCT-CA. There were 37 significant lesions on 1,098 available coronary segments. Sensitivity, specificity and positive and negative predictive value of MSCT-CA for detecting significant coronary artery on a per-segment basis were 100%, 98.6%, 71.2% and 100%, respectively. All patients with at least one significant lesion were correctly identified by MSCT-CA. MSCT-CA scored 15 false positives on a per-segment base, which affected only marginally the per-p.atient performance (only one false positive).ConclusionsWe concluded that 64-slice CT-CA is a diagnostic modality with high sensitivity and negative predictive value in patients at low to intermediate risk.RiassuntoObiettivoValutare l’accuratezza diagnostica dell’angiografia coronarica non invasiva con tomografia computerizzata (AC-TC) a 64 strati nell’individuazione delle stenosi coronariche significative (riduzione del lume coronarico ≥ 50%) in una popolazione di pazienti a basso-intermedio rischio cardiovascolare.Materiali e metodiSono stati studiati 72 pazienti (38 maschi, 34 donne, età media 53,9±8,0 anni) che presentavano dolore toracico atipico o angina pectoris stabile e che venivano stratificati nella categoria del rischio basso-intermedio. Per la scansione AC-TC sono stati iniettati endovena 100 ml di mezzo di contrasto (Iomeprolo 400 mgI/ml, Bracco, Italia). Due osservatori, in cieco rispetto alla coronarografia convenzionale CAG), hanno valutato in consenso le immagini dell’AC-TC. Sono stati quindi calcolati i valori di accuratezza diagnostica per la rilevazione di stenosi significative.RisultatiL’angiografia coronarica invasiva ha dimostrato l’assenza di malattia o la presenza di malattia non critica nel 70,1% dei pazienti (51/72). Nessun paziente è stato escluso dalla popolazione studiata. Sono state individuate 37 lesioni significative su 1098 segmenti disponibili. Sensibilità, specificità, valore predittivo positivo e negativo dell’AC-TC nella determinazione delle stenosi significative utilizzando un’analisi per segmenti sono risultate, rispettivamente, del 100%, 98,6%, 71,2% e 100%. Tutti i pazienti con almeno una lesione significativa sono stati correttamente identificati anche nella valutazione con AC-TC. L’AC-TC ha generato 15 falsi postivi su base segmentale che però si riducono a un solo falso positivo nell’analisi per paziente.ConclusioniL’AC-TC a 64 strati rappresenta una metodica diagnostica ad elevata sensibilità e valore predittivo negativo nei pazienti con rischio basso o intermedio.

Focal liver lesions: sinusoidal phase of CEUS

Ultrasound examination is the first imaging modality for hepatic study in neoplastic and chronic liver diseases. Focal liver lesions frequently cause diagnostic problems in terms of characterization, especially when small and hypoechoic to the rest of the parenchyma. Contrast- enhanced ultrasonography (CEUS) has shown its value in the characterization of focal liver lesions. This study assessed the value of the sinusoidal phase of CEUS with a second-generation contrast agent in the characterization of focal liver lesions to distinguish benign from malignant. Two hundred hepatic lesions with suspicious features at baseline ultrasound were prospectively studied with CEUS. Sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy of the sinusoidal phase in the characterization of benign versus malignant liver lesions were evaluated. Hypoechogenicity of the focal liver lesion, during the sinusoidal phase of CEUS, allowed the diagnosis of malignancy with a sensitivity of 85%, specificity of 88%, positive predictive value of 92%, negative predictive value of 77%, and diagnostic accuracy of 86%. The diagnostic confidence in the diagnosis of malignancy significantly increased, with receiver operating characteristic curve areas from 0.536 for baseline ultrasound to 0.902 for the sinusoidal phase of CEUS.

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.

Intrahepatic peripheral cholangiocarcinoma (IPCC): comparison between perfusion ultrasound and CT imaging

PurposeThis study was done to compare the perfusion patterns of intrahepatic peripheral cholangiocarcinoma (IPCC) on contrast-enhanced ultrasound (CEUS) and dynamic computed tomography (CT).Materials and methodsWe retrospectively reviewed 23 histologically proven cases of IPCC. All lesions were studied by CEUS with sulfur hexafluoride-filled microbubbles coated with a phospholipid capsule, and by dynamic CT. Contrast-enhancement patterns were evaluated in the arterial phase (CEUS 10–20 s after the injection; CT 25–30 s after the injection) and in the delayed phase (CEUS 120 s after the injection; CT>2–3 min after the injection).ResultsLesions were single in 18/23 cases (78%), single with nearby satellite lesions in 1/23 (4%) cases and multifocal with distant secondary lesions in 4/23 (17%) cases. Lesion diameter was 2–5 cm in 7/23 cases (30%), 5–7 cm in 13/23 cases (57%) and >7 cm in 3/23 (13%) cases. On CEUS, lesions were hypervascular in 16/23 cases (70%). On delayed-phase CEUS, 22/23 lesions (96%) were markedly hypoechoic. CT showed that the lesions were hypovascular in the arterial phase in 15/23 cases (66%) and hypervascular in 7/23 (30%) cases; one lesion (1/23; 4%) was isovascular. On delayed-phase CT, lesions were hyperdense in 17/23 cases (74%), hypodense in 5/23 (22%) cases and isodense in 1/23 (43%) cases.ConclusionsEnhancement discrepancy between delayed-phase CEUS (hypoechogenicity) and CT (hyperdensity) is common semiological findings in the study of IPCC.RiassuntoObiettivoConfrontare le caratteristiche perfusionali del colangiocarcinoma intra-epatico periferico (IPCC) in ecografia con mdc (CEUS) e TC dinamica.Materiali e metodiAnalisi retrospettiva di 23 casi di colangiocarcinoma periferico istologicamente accertati. Tutte le lesioni sono state studiate con CEUS utilizzando microbolle a base di esaflururo di zolfo ricoperte da una capsula di fosfolipidi quale mezzo di contrasto e con TC dinamica. Sono state valutate le caratteristiche della impregnazione lesionale nelle fasi arteriosa (CEUS: 10–20 s dopo l’iniezione; TC: 25–30 s dopo l’iniezione) e tardiva (CEUS: 120 s dopo l’iniezione; TC>2–3 min dopo l’iniezione).RisultatiIn 18/23 (78%) la lesione era singola, in 1/23 (4%) singola con lesioni satelliti a ridosso della lesione principale e in 4/23 (17%) multifocale con lesioni a distanza rispetto alla lesione prinicipale. Le dimensioni delle lesioni erano comprese tra 2 e 5 cm di diametro in 7/23 (30%), tra 5 e 7 cm in 13/23 (57%) e superiori a 7 cm in 3/23 (13%). La CEUS ha evidenziato ipervascolarizzazione delle lesioni in 16/23 (70%). Ventidue su 23 lesioni (96%) in fase tardiva CEUS, sono risultate marcatamente ipoecogene. La TC ha evidenziato ipovascolarizzazione delle lesioni in fase arteriosa in 15/23 (66%) ed ipervascolarizzazione in 7/23 (30%); una lesione (1/23; 4%) era isovascolarizzata. In fase tardiva TC la lesione era iperdensa in 17/23 (74%) casi, ipodensa in 5/23 (22%) e isodensa in 1/23 (43%) casi.ConclusioniIl riscontro di una discordanza di enhancement in fase tardiva tra CEUS (ipoecogenicità) e TC (iperdensità) rappresenta frequente rilievo semeiologico nello studio del colangiocarcinoma intraepatico periferico.

Resectable Pancreatic Adenocarcinoma: Is the Enhancement Pattern at Contrast-Enhanced Ultrasonography a Pre-Operative Prognostic Factor?

The aim of our study was to determine whether the enhancement pattern of pancreatic adenocarcinoma at contrast-enhanced ultrasonography (CEUS) is related to patient prognosis after resection. CEUS of 42 resected adenocarcinomas were retrospectively reviewed. Tumors were divided into two groups: group A=poorly vascularized (presence of avascular areas) or group B=well vascularized (absence of avascular areas). All lesions were resected and underwent pathological examination assessing tumor differentiation as: undifferentiated (poorly differentiated) or differentiated (moderately and well differentiated). Mean vascular density (MVD) was also evaluated. CEUS enhancement and pathology were correlated (Spearmans test). Survival was analyzed with the Kaplan-Meier method. Multivariate analysis was performed with the Cox regression model. There were 30 differentiated and 12 undifferentiated adenocarcinomas at pathology. At CEUS, 10 lesions were poorly vascularized, whereas 32 lesions were well vascularized. Positive correlation was observed between CEUS groups and tumoral differentiation (rs=0.51; p=0.001) and between CEUS and MVD (rs=0.74; p<0.0001). Median survival in patients with group A vascularization at CEUS was significantly lower than in group B (p=0.015). Cox proportional hazard model revealed the presence of poorly vascularized tumor at CEUS (p=0.0001) as a predictor of higher mortality. In conclusion, CEUS enables accurate depiction of the vascularization of adenocarcinoma, with positive correlation to histology grade and MVD.