Julio Martín

Liver tumor characterization: Comparison between liver-specific gadoxetic acid disodium-enhanced MRI and biphasic CT - A multicenter trial

Objective: In our multi center trial we compared the potentials of biphasic contrast-enhanced computed tomography (CT) and a novel tissue-specific magnetic resonance imaging (MRI) contrast agent gadoxetic acid disodium in liver lesion characterization. Methods: A total of 176 patients with 252 liver lesions were analyzed. There were 104 malignant and 148 benign lesions. High-field strength (1.0 T or 1.5 T) MR systems with T1-and T2-weighted sequences were used with and without fat suppression. After gadoxetic acid disodium injection, dynamic imaging and hepatocyte phase MR imaging were performed. Biphasic with 150 mg I/kg of body weight (100-200 mL) spiral CT was also performed. Image reading consisted of on-site (by study investigators) and fully blinded off-site (by E.S.P; C.R; and A.S) evaluations. The classification (benign or malignant) and characterization (lesion type) outcomes of both techniques were assessed. All imaging results were verified against a standard of reference. Results: Both on-site and off-site evaluations demonstrated increases in the lesion classification accuracy with gadoxetic acid disodium-enhanced MRI when compared with spiral CT. This improvement was also shown for characterization. Gadoxetic acid disodium was well tolerated. Conclusions: Gadoxetic acid disodium offers a safe and diagnostically powerful tool for the evaluation of patients with focal liver lesions with a reliable assessment of lesion classification and characterization.

Comparison of 1.0 M gadobutrol and 0.5 M gadopentetate dimeglumine-enhanced magnetic resonance imaging in five hundred seventy-two patients with known or suspected liver lesions: results of a multicenter, double-blind, interindividual, randomized clinical phase-III trial

Objective:To evaluate the diagnostic efficacy (accuracy, sensitivity, specificity) of 1.0 M gadobutrol versus 0.5 M gadopentetate for the classification of lesions as either benign or malignant in patients with known or suspected liver lesions. Methods and Materials:A multicenter, phase-III, randomized, interindividually controlled comparison study with blinded reader evaluation was performed to investigate the diagnostic efficacy of a bolus injection of 1.0 M gadobutrol compared with 0.5 M gadopentetate at a dose of 0.1 mmol Gd/kg BW. The imaging protocol included a dynamic 3D-evaluation, static conventional, and fat saturated T1-weighted sequences. MR datasets were evaluated by 3 independent radiologists. The standard of reference was defined by an independent truth panel (radiologist or hepatologist). The safety evaluation included adverse events, vital signs, and physical examination. Results:A total of 497 of 572 patients were eligible for the final efficacy analysis. Noninferiority of gadobutrol-enhanced magnetic resonance imaging (MRI) for the classification of liver lesions was demonstrated on the basis of diagnostic accuracy determined by the on-site investigators (−0.098, 0.021) as well as for the average reader of the blinded evaluation (−0.096, 0.014) (95% confidence interval), compared with the predefined standard of reference. Very similar increases in sensitivity (ranging from ∼10% to ∼55%) and specificity (ranging from ∼1%–∼18%) compared with precontrast MRI were also observed for the 2 contrast agent groups, with maximum differences of 4%.Very similar, low rates of adverse events were recorded for each of the 2 groups. No clinically relevant changes in vital signs or the results of the physical examination were observed in any patient. Conclusion:This study documents evidence for the noninferiority of a single i.v. bolus injection of 1.0 M gadobutrol (0.1 mmol/kg body weight) to 0.5 M gadopentetate (0.1 mmol/kg body weight) in the diagnostic assessment of liver lesions with contrast-enhanced MRI. The known excellent safety profile of gadobutrol was confirmed in this clinical trial and is similar to that of gadopentetate.

Magnetic resonance of focal liver lesions in hepatic cirrhosis and chronic hepatitis

Detection of focal liver nodules in patients with cirrhosis continues to be a radiologic challenge despite progressive advances in liver imaging in the past 2 decades. Patients with hepatic cirrhosis have a high predisposition to develop hepatocellular carcinoma (HCC), and the early detection and diagnosis of this tumor is very important because the most effective treatment is surgical resection, transplantation, or local ablation therapy when the tumor is small. Cirrhotic livers are mainly composed of fibrosis, together with a broad spectrum of focal nodular lesions ranging from regenerative nodules to premalignant dysplastic nodules to overt HCC. Awareness of such lesions and interpretation of imaging studies in these patients requires a critical review to detect subtle tumors, and a thorough understanding of the imaging appearance of the malignant and benign masses that can occur in the cirrhotic liver. Although the recent advances in liver imaging techniques, especially computed tomography (CT) and magnetic resonance (MR), have facilitated the detection and characterization of focal liver nodules in cirrhotic patients, discriminating between HCC and precancerous nodules remains problematic with all available imaging techniques. Nevertheless, MR imaging appears to have more potential than other imaging techniques in the study of cirrhotic patients and MR may be more appropriate than the other imaging modalities for the detection of small HCCs. In this article we review the imaging characteristics of nodular focal lesions that arise in cirrhotic livers, with special attention to MR imaging features.

Estudio prospectivo comparativo en el diagnóstico de la patología biliar. Colangiopancreatografía por resonancia magnética frente a colangiografía directa

Objetivo Valorar la sensibilidad y especificidad de la colangiopancreatografia por resonancia magnetica (CPRM) como tecnica diagnostica no invasiva, frente a la colangiopancreatografia retrograda endoscopica (CPRE) o colangiografia transparietohepatica (CTPH) en el diagnostico de la patologia biliar y especificamente de la coledocolitiasis. Material y metodos Durante el periodo comprendido entre junio de 1997 y febrero de 1998, se evaluaron 109 pacientes procedentes de la Corporacio Sanitaria del Parc Tauli y del Hospital Mutua de Terrassa. En todos los casos se realizaron la CPRM y la CPRE o CTPH en este orden y con un intervalo maximo de siete dias entre ambas. Se excluyeron del estudio 24 pacientes por diversas causas, incluyendose finalmente 85 pacientes. Todos los estudios se realizaron mediante un equipo Siemens Magneton Impact Expert de 1 Tesla realizando secuencias HASTE y RARE en diversas proyecciones coronales y axiales. La lectura de las CPRM fue realizada por dos radiologos expertos en la valoracion de la patologia digestiva por el metodo de consenso. Resultados En la valoracion de los 85 pacientes la CPRM obtuvo una sensibilidad del 98,4%, una especificidad del 94,7%, un valor predictivo positivo del 98,4% y un valor predictivo negativo del 94,7% en la deteccion de patologia biliar. En relacion a la coledocolitiasis se obtuvo una S = 100% E = 89,5%, VPP = 88% y VPN = 100%. Conclusion La CPRM tiene una alta precision diagnostica en la patologia biliar y especialmente en la coledocolitiasis. Su alto valor predictivo negativo permite obviar la realizacion de otras pruebas diagnosticas invasivas.