Renal artery stenosis evaluation: diagnostic performance of gadobenate dimeglumine-enhanced MR angiography--comparison with DSA

PURPOSE: To prospectively determine diagnostic performance and safety of contrast material-enhanced (CE) magnetic resonance (MR) angiography with 0.1 mmol per kilogram of body weight gadobenate dimeglumine for depiction of significant steno-occlusive disease (> or =51% stenosis) of renal arteries, with digital subtraction angiography (DSA) as reference standard. MATERIALS AND METHODS: This multicenter study was approved by local institutional review boards; all patients provided written informed consent. Patient enrollment and examination at centers in the United States complied with HIPAA. Two hundred ninety-three patients (154 men, 139 women; mean age, 61.0 years) with severe hypertension (82.2%), progressive renal failure (11.3%), and suspected renal artery stenosis (6.5%) underwent CE MR angiography with three-dimensional spoiled gradient-echo sequences after administration of 0.1 mmol/kg gadobenate dimeglumine at 2 mL/sec. Anteroposterior and oblique DSA was performed in 268 (91.5%) patients. Three independent blinded reviewers evaluated CE MR angiographic images. Sensitivity, specificity, and accuracy of CE MR angiography for detection of significant steno-occlusive disease (> or =51% vessel lumen narrowing) were determined at segment (main renal artery) and patient levels. Positive and negative predictive values and positive and negative likelihood ratios were determined. Interobserver agreement was analyzed with generalized kappa statistics. A safety evaluation (clinical examination, electrocardiogram, blood and urine analysis, monitoring for adverse events) was performed. RESULTS: Of 268 patients, 178 who were evaluated with MR angiography and DSA had significant steno-occlusive disease of renal arteries at DSA. Sensitivity, specificity, and accuracy of CE MR angiography for detection of 51% or greater stenosis or occlusion were 60.1%-84.1%, 89.4%-94.7%, and 80.4%-86.9%, respectively, at segment level. Similar values were obtained for predictive values and for patient-level analyses. Few CE MR angiographic examinations (1.9%-2.8%) were technically inadequate. Interobserver agreement for detection of significant steno-occlusive disease was good (79.9% agreement; kappa = 0.69). No safety concerns were noted. CONCLUSION: CE MR angiography performed with 0.1 mmol/kg gadobenate dimeglumine, compared with DSA, is safe and provides good sensitivity, specificity, and accuracy for detection of significant renal artery steno-occlusive disease

Renal artery stenosis evaluation : Diagnostic performance of gadobenate dimeglumine - Enhanced MR angiography - Comparison with DSA

Purpose: To prospectively determine diagnostic performance and safety of contrast material\u2013enhanced (CE) magnetic resonance (MR) angiography with 0.1 mmol per kilogram of body weight gadobenate dimeglumine for depiction of significant steno-occlusive disease ( 6551% stenosis) of renal arteries, with digital subtraction angiography (DSA) as reference standard. Materials and Methods: This multicenter study was approved by local institutional review boards; all patients provided written informed consent. Patient enrollment and examination at centers in the United States complied with HIPAA. Two hundred ninety-three patients (154 men, 139 women; mean age, 61.0 years) with severe hypertension (82.2%), progressive renal failure (11.3%), and suspected renal artery stenosis (6.5%) underwent CE MR angiography with three-dimensional spoiled gradient-echo sequences after administration of 0.1 mmol/kg gadobenate dimeglumine at 2 mL/sec. Anteroposterior and oblique DSA was performed in 268 (91.5%) patients. Three independent blinded reviewers evaluated CE MR angiographic images. Sensitivity, specificity, and accuracy of CE MR angiography for detection of significant steno-occlusive disease ( 6551% vessel lumen narrowing) were determined at segment (main renal artery) and patient levels. Positive and negative predictive values and positive and negative likelihood ratios were determined. Interobserver agreement was analyzed with generalized \u3ba statistics. A safety evaluation (clinical examination, electrocardiogram, blood and urine analysis, monitoring for adverse events) was performed. Results: Of 268 patients, 178 who were evaluated with MR angiography and DSA had significant steno-occlusive disease of renal arteries at DSA. Sensitivity, specificity, and accuracy of CE MR angiography for detection of 51% or greater stenosis or occlusion were 60.1%\u201384.1%, 89.4%\u201394.7%, and 80.4%\u201386.9%, respectively, at segment level. Similar values were obtained for predictive values and for patient-level analyses. Few CE MR angiographic examinations (1.9%\u20132.8%) were technically inadequate. Interobserver agreement for detection of significant steno-occlusive disease was good (79.9% agreement; \u3ba = 0.69). No safety concerns were noted. Conclusion: CE MR angiography performed with 0.1 mmol/kg gadobenate dimeglumine, compared with DSA, is safe and provides good sensitivity, specificity, and accuracy for detection of significant renal artery steno-occlusive disease

Renal artery stenosis evaluation: diagnostic performance of gadobenate dimeglumine-enhanced MR angiography--comparison with DSA

articleInternational audienc

COLANGIORESONANCIA (CPRM) VS ULTRASONIDO (US) FOCALIZADO EN PACIENTES CON ICTERICIA O SOSPECHA DE OBSTRUCCION DE LA VIA BILIAR: RESULTADOS PRELIMINARES

Introducción. Existe controversia en el algoritmo de estudio de obstrucción de la vía biliar (VB). La colangiopacreatografía endoscópica retrógrada (ERCP) ha sido el examen de referencia. La colangioresonancia (CPRM) es un examen no invasivo con buena correlación entre observadores al evaluar la VB, pero aún cuestionada en nuestro medio por su mayor costo. El US convencional focalizado detecta dilatación de VB y disminuye los costos del algoritmo de estudio, seleccionando los pacientes que debieran referirse a otros métodos de estudio más costosos o invasivos (CPRM-ERCP). Objetivo. Comparar la validez, valores predictivos y cambios de probabilidad post-test de CPRM y US focalizado a la VB, en el estudio de pacientes con ictericia o sospecha de obstrucción biliar. Materiales y métodos. Se realizó un ensayo clínico pareado ciego. La muestra la constituyeron pacientes con sospecha de patología obstructiva de la VB a los cuales se les solicitó CPRM entre Enero-Julio 2003. Se les realizó US 24 hr antes o después de la CPRM por ecografistas de diferente experiencia. La CPRM se realizó con protocolos estándar, se registró el uso de Gadolinio y secuencias adicionales. El estándar dorado lo constituyeron la cirugía, la ERCP, seguimiento de al menos 30 días y revisión de informes de Anatomía Patológica. Se clasificó el riesgo de obstrucción de la VB en alto, moderado o bajo. Análisis. Se construyeron tablas de contingencia de 2x2 para estimar los valores del test: Sensibilidad (S), Especificidad (E), Valores predictivos positivo (VPP) y negativo (VPN), Likelihood ratios (LR) y probabilidades pre y post test. Resultados. Muestra constituida por 76 pacientes de los cuales 64 han completado el seguimiento. En el grupo de Alto riesgo en 21 pacientes se comprobó obstrucción, en 1 de los de moderado, en ninguno de los de bajo riesgo y en 2 de los no clasificados. La prevalencia de obstrucción (probabilidad pre-test) fue de 24/64 (37.5%). El US encontró dilatación de la VB en el 50% de los pacientes y la CPRM en el 48%. La principal causa de obstrucción fue la coledocolitiasis (25%), siendo las neoplasias la segunda. Para el diagnóstico de obstrucción de la vía biliar de cualquier causa el US mostró una S de 58.33%, la cual aumentó a 70% cuando el ecografista era experimentado, una E de 82.5%, VPP de 66.67% y VPN de 76.74% y LR(+) de 3.3 con una probabilidad post-test de 55%, un LR(-) de 0.49 con una probabilidad post-test de 20%. La CPRM para este mismo diagnóstico presentó una S de 95.83% y una E de 87.5%, así como un VPP de 82.14% y VPN de 97.22%; un LR(+) de 7.7 lo que lleva a una probabilidad post-test de 80% y un LR(-) de 0.05, con una probabilidad post-test de 3%. Para coledocolitiasis los VP(+) y VP(-) fueron, respectivamente, 53.33% y 83.67% para el US, y 70% y 95.45% para la CPRM. Conclusiones. CPRM posee sensibilidad, valores predictivos y LR(s) mejores que ultrasonido focal en la detección de obstrucción de la vía biliar. Ambos métodos poseen valores cercanos de Especificidad y de detección de dilatación de los conductos biliares. En el algoritmo de estudio de un paciente con sospecha de obstrucción de la vía biliar usar US en serie y luego CPRM cuando no se diagnostica la causa de obstrucción, sería la alternativa actual, probablemente más costo-efectiva en el estudio de estos pacientes.Between January and July, 2003, a single blinded matched trial was done to assess focalized biliary ultrasound (US) and MR cholangiography (MRCP) compared with ERCP or surgery as reference standard in patients with suspected biliary obstruction. Focalized US was performed 24 hrs before/after MRCP. Patients were triage according symptoms, signs and laboratory in high, intermediate and low risk for obstruction. Radiologists sonographers were divided in low and highly experienced. None of the radiologist who reported either US or MRCP was aware to the other test results. Sensitivity, Specificity, PPV and NPV, (LR) Likelihood Ratios and pre and post-test odds for positive and negative test were estimated. We analized 64 out of 76 sampled patients, the prevalence of obstruction was 37 % (24 out of 64 patients). US found biliary tree dilated in 50% and MRCP in 48% of the patients. Main cause of obstruction was common bile duct stones in (16) 25%. and tumors were the second more common cause. US shown a Sensitivity (S) 58.3% when a non experienced radiologist perform the exam, and 70% when an experienced radiologist doest it. Specificity (Sp) 82,5%, PPV 66.7% and NPV 76.7%. RMCP Shown S 95.8%, Sp 87.5%, PPV 82.1%, NPV 97.2% For common bile duct stones US shown a PPV 53.3% and NPV 83.6% on the other hand MRCP a PPV 70% and NPV 95.4%. MRCP perform better than focalized US in overall patients with high risk of obstruction (37.5%), detecting the cause of obstruction but using aditional sequences rising the examination time and costs. With a positive ultrasound and LR(+) 3.3 pre-test odds rise from 0.37/37% to a post-test odds of 0.55/55% and with negative test result and LR(-) 0.49 pre-test odds 0.37/37% will decrease to post-test odds of 0.2/20%. With MRCP a positive test with LR(+) 7.7 initial pre-test odds 0.37/37.5% to post-test odds of 0.8/ 80% and with a negative test result LR(-) 0.05 pretest odds 0.37/37% will decrease to post-test odds of 0.03%. Ultrasound performed by experienced sonographers has a Specificity and NPV over 80%, and perform similar to MRCP for detecting biliary tree dilatation the best predictor of obstruction. In patients with low pre-test odds (low risk) of obstruction, to use focalized US and then MRCP, when the cause of obstruction is not diagnosed could be the more cost/efective initial alternative in this patients. This data must be confirmed with further studies with cost/effectivenes analysis