Estandarización de la cuantificación de la concentración de hierro en el hígado por resonancia magnética / Standardization of the quantification of iron concentration in the liver by magnetic resonance imaging

Objetivo. Calibrar máquinas de RM de 1,5 teslas para la cuantificación de la concentración de hierro en el hígado. Material y métodos. En 28 RM de 1,5 teslas se ha analizado un fantoma con cuatro tubos con diferentes concentraciones de cloruro de hierro III y uno sin hierro, que reproduce a dos pacientes promedio con sobrecarga férrica moderada y alta con las secuencias de un modelo de cuantificación. Se midió para cada tubo la ratio de intensidad de señal con el tubo sin hierro y se calcularon los niveles de concentración teóricos en cada máquina según el modelo para los dos niveles de sobrecarga. Se compararon los resultados con los de la máquina de referencia en la que se habían diseñado el modelo y el fantoma, calculando la diferencia porcentual. Resultados. La diferencia porcentual media de las ratios con respecto a los del centro de referencia fue 11% (0,3-39). La media de los valores de concentración de hierro fue de 71μmol Fe/g para la sobrecarga media, y de 193μmol Fe/g para la sobrecarga alta. La diferencia porcentual media fue del 6% (1,2-37%) y 3,4% (0-16%) respectivamente. En dos máquinas se aplicó un factor de corrección de forma que la diferencia porcentual fue inferior al 25% en todos los casos. Conclusión. Se han calibrado 28 máquinas de 1,5 teslas para la cuantificación de la concentración de hierro en el hígado con una variabilidad menor del 25% (AU)

Objective. To calibrate 1.5 tesla magnetic resonance scanners for the quantification of the concentration of iron in the liver. Material and methods. We analyzed twenty-eight 1.5 tesla magnetic resonance scanners using a phantom with four tubes containing different concentrations of iron (III) chloride and one tube without iron. The phantom represented two typical patients: one with moderate iron overload and one with high iron overload. We measured the signal intensity ratio between each iron-containing tube and the tube without iron; then we calculated the theoretical levels of iron concentration in each scanner according to the model for the two levels of overload. We compared the results of each scanner with those of the reference scanner in which the model and the phantom had been designed, and we calculated the percentage of difference between the two scanners. Results. The mean difference in the ratios compared to the reference center was 11% (0.3-39). The mean concentration of iron was 71μmol Fe/g for moderate overload and 193μmol Fe/g for high overload. The mean difference was 6% (1.2- 7%) and 3.4% (0-16%). respectively. In two scanners, we applied a correction factor so that the difference was below 25% in all cases. Conclusion. We calibrated twenty-eight 1.5 tesla scanners for the concentration of iron in the liver and achieved variability less than 25% (AU)

[Standardization of the quantification of iron concentration in the liver by magnetic resonance imaging]. / Estandarización de la cuantificación de la concentración de hierro en el hígado por resonancia magnética.

OBJECTIVE: To calibrate 1.5 tesla magnetic resonance scanners for the quantification of the concentration of iron in the liver. MATERIAL AND METHODS: We analyzed twenty-eight 1.5 tesla magnetic resonance scanners using a phantom with four tubes containing different concentrations of iron (III) chloride and one tube without iron. The phantom represented two typical patients: one with moderate iron overload and one with high iron overload. We measured the signal intensity ratio between each iron-containing tube and the tube without iron; then we calculated the theoretical levels of iron concentration in each scanner according to the model for the two levels of overload. We compared the results of each scanner with those of the reference scanner in which the model and the phantom had been designed, and we calculated the percentage of difference between the two scanners. RESULTS: The mean difference in the ratios compared to the reference center was 11% (0.3-39). The mean concentration of iron was 71 µmol Fe/g for moderate overload and 193 µmol Fe/g for high overload. The mean difference was 6% (1.2- 7%) and 3.4% (0-16%). respectively. In two scanners, we applied a correction factor so that the difference was below 25% in all cases. CONCLUSION: We calibrated twenty-eight 1.5 tesla scanners for the concentration of iron in the liver and achieved variability less than 25%.

Eficacia de los programas de cribado de hepatocarcinoma: ¿mejoran las opciones terapéuticas de estos pacientes? / Are hepatocellular carcinoma surveillance programs effective at improving the therapeutic options?

Objetivo: determinar si la utilización en nuestro medio delprograma de cribado de HCC establecido –alfa-fetoproteína (AFP)y ecografia semestral– en pacientes con hepatopatía crónica permitedetectar pacientes en estadios precoces de la enfermedad.Material y métodos: Diseño experimental: estudio retrospectivo.Criterios diagnósticos de HCC: 2 o más técnicas de imagencon lesión hipervascular mayor de 2 cm o 1 técnica de imagencon lesión hipervascular mayor de 2 cm asociado a AFPmayor de 400 ng/ml. Pacientes: 85 pacientes diagnosticados deHCC en el Hospital Donostia entre los años 2003 y 2005. Datosanalizados: información demográfica (sexo, edad), factores deriesgo (alcohol, virus de hepatitis, hemocromatosis, otras enfermedadesasociadas), e información clínica (etiología de la hepatopatía,estadio de Child-Pugh, determinación de AFP, hallazgos radiológicos,criterios de resecabilidad, tratamiento recibido,evolución). Se divide la muestra en dos grupos según hubieran seguidoo no un programa de cribado.Resultados: el 70% de los pacientes del grupo de cribado sediagnostican en estadio precoz frente al 26,7% del grupo de nocribado (p < 0,05). Trece pacientes no pueden recibir tratamientocurativo a pesar del diagnóstico en fase precoz (9 en el grupo decribado y 4 en el de no cribado). La sensibilidad global del cribadoen nuestra serie es del 95%.Conclusiones: en nuestro medio, el programa de cribado dehepatocarcinoma es eficaz en términos de aplicación de tratamientoscurativos(AU9

Aim: to evaluate whether the current surveillance programs(ultrasonography and alpha-fetoprotein testing every six months)are successful in detecting patients in the early stages.Material and methods: the health records of all patientsdiagnosed with hepatocellular carcinoma in Donostia Hospitalbetween 2003 and 2005 were reviewed retrospectively. Eightyfivepatients (11 women and 74 men) were included in the studyand demographic data, risk factors and clinical data were obtained.Patients were split into two groups according to whether ornot they had been included in a surveillance program.Results: seventy per cent of patients of the surveillance groupis diagnosed in early stage opposite to 26.7% of patients in nosurveillance group (p < 0.05). Thirteen patients cannot receivecurative treatment in spite of the diagnosis in early stage (9 in thesurveillance group and 4 in the no surveillance group. The globalsensibility of the surveillance program in our series is 95%.Conclusions: current hepatocellular carcinoma surveillanceprograms, which comprise six-monthly ultrasonography and alpha-fetoprotein tests, are highly sensitive and effective. These programsresult in the detection of hepatocellular carcinoma in itsearly-stages, when potentially curative treatment may be offered(AU)

Are hepatocellular carcinoma surveillance programs effective at improving the therapeutic options.

AIM: to evaluate whether the current surveillance programs (ultrasonography and alpha-fetoprotein testing every six months) are successful in detecting patients in the early stages. MATERIAL AND METHODS: the health records of all patients diagnosed with hepatocellular carcinoma in Donostia Hospital between 2003 and 2005 were reviewed retrospectively. Eighty-five patients (11 women and 74 men) were included in the study and demographic data, risk factors and clinical data were obtained. Patients were split into two groups according to whether or not they had been included in a surveillance program. RESULTS: seventy per cent of patients of the surveillance group is diagnosed in early stage opposite to 26.7% of patients in no surveillance group (p < 0.05). Thirteen patients cannot receive curative treatment in spite of the diagnosis in early stage (9 in the surveillance group and 4 in the no surveillance group. The global sensibility of the surveillance program in our series is 95%. CONCLUSIONS: current hepatocellular carcinoma surveillance programs, which comprise six-monthly ultrasonography and alpha-fetoprotein tests, are highly sensitive and effective. These programs result in the detection of hepatocellular carcinoma in its early-stages, when potentially curative treatment may be offered.

[Arteriographic correlation in 30 patients with renal vascular disease diagnosed with multislice CT]. / Correlación arteriográfica en 30 pacientes con patología vascular renal diagnosticada mediante TC multicorte.

OBJECTIVE: To determine the usefulness of multislice computed tomography (MSCT) in the evaluation of renal vascular disease against a gold standard of digital subtraction angiography (DSA). MATERIAL AND METHODS: We evaluated 30 patients with arterial hypertension and/or kidney failure that underwent MSCT to rule out a vascular cause and DSA to confirm a vascular cause suspected at MSCT. MSCT examinations were performed on a 10-detector scanner with intravenous administration of 80 ml of iodinated contrast (300 mg iodine/ml) at a flow rate of 5 ml/s. A total of 71 renal arteries, 56 main and 15 accessory, were evaluated. Arterial stenoses were classified as: grade 0 (normal artery), grade I (stenosis < 50%), grade II (> or = 50% and < 70%), grade III (> or = 70%), grade IV (occlusion). Stenosis > or = grade II was considered hemodynamically significant. RESULTS: The findings at MSCT and DSA were identical in 56 (78.8%) renal arteries; MSCT overestimated the degree of stenosis in 13 (18.3%) cases. All grade III stenoses were detected at MSCT. In the diagnosis of hemodynamically significant stenosis, MSCT had a sensitivity of 96.5%, specificity 78.5%, accuracy 85.9%, positive predictive value 75.6%, and negative predictive value 97%. CONCLUSIONS: MSCT is a good noninvasive imaging technique for the evaluation of renal vessels; it is useful for screening patients with kidney disease to rule out potentially treatable vascular causes.

[Utility of various non-invasive methods for fibrosis prediction among Basque Country patients with phenotypic hemochromatosis]. / Utilidad de los diferentes métodos no invasivos de predicción de fibrosis hepática en pacientes del País Vasco con hemocromatosis fenotípica.

OBJECTIVE: To determine whether the product of multiplying age by liver iron concentration (LIC) (fibrosis index; cut-off, 480,000), platelets, transaminases, and ferritin values are related to the risk of high grade fibrosis. METHODS: A retrospective study of 32 patients with hereditary hemochromatosis (HH) with phenotypic expression. All patients had a liver biopsy with LIC. RESULTS: In 7 patients a magnetic resonance imaging (MRI) scan (1.5 T) was obtained with LIC following Alustiza's protocol. Liver biopsy: fibrosis grade (F) 0-2 in 23 patients; F 3-4 in 9. Fibrosis index (FI) showed a specificity of 68%, sensitivity of 85.7%, positive predictive value (PPV) of 42.8%, and negative predictive value (NPV) of 94.4% for high-grade fibrosis. Platelet count ( < 200,000) revealed a NPV of 94.7% for F3-4. Aspartate transaminase (AST) levels above the upper limit of normal showed a NPV of 94.4%; ferritin levels (> 1,000) a NPV of 75%, and MRI-derived LIC x age (> 480,000) a NPV of 80%. The combination of FI (either by biopsy or MRI) with transaminases, and of platelets with transaminases revealed a NPV of 100%. CONCLUSIONS: FI > 480,000 and platelets < 200,000 have the highest sensitivity for high-degree fibrosis prediction. A negative result allows to discard significant fibrosis in 94% of cases. MRI allows a good fibrosis prediction.

Post-operative lumbar spine: comparative study of TSE T2 and turbo-FLAIR sequences vs contrast-enhanced SE T1.

AIM: To compare turbo T2 weighted spin echo (TSE T2) and turbo-FLAIR (fluid attenuated inversion recovery) vs gadolinium enhanced T1 weighted spin echo (SE T1) sequence in the differential diagnosis between disc herniation and post-surgical fibrosis. MATERIALS AND METHODS: Sixty-four patients who underwent surgical treatment for lumbar disc herniation with persistent or recurrent post-surgical symptoms were studied with a 0.5 Tesla MR system. The sequences used were TSE T2, turbo-FLAIR and T1 SE with and without intravenous gadolinium DTPA. The enhanced T1 SE sequence was considered the gold standard. Sensitivity and specificity were calculated. RESULTS: The sensitivity was 100% for both TSE T2 and turbo-FLAIR sequences. The specificity was 94% for TSE T2 and 92% for turbo-FLAIR. Negative predictive value was 100% for both sequences and positive predictive value 84% and 80% for TSE T2 and turbo-FLAIR, respectively. CONCLUSION: Although both sequences show high sensitivity, TSE-T2 presents greater specificity than turbo-FLAIR as compared to enhanced T1 SE. TSE T2 also offers the advantage of myelographic effect. We consider that the use of rapid sequences may avoid the need for intravenous contrast medium in most cases, reserving gadolinium DTPA only to those where all the criteria for hernia or fibrosis are not fulfilled.

Lateral stabilizing structures of the knee: functional anatomy and injuries assessed with MR imaging.

The lateral aspect of the knee is stabilized by a complex arrangement of ligaments, tendons, and muscles. These structures can be demonstrated with routine spin-echo magnetic resonance (MR) imaging sequences performed in the sagittal, coronal, and axial planes. Anterolateral stabilization is provided by the capsule and iliotibial tract. Posterolateral stabilization is provided by the arcuate ligament complex, which comprises the lateral collateral ligament; biceps femoris tendon; popliteus muscle and tendon; popliteal meniscal and popliteal fibular ligaments; oblique popliteal, arcuate, and fabellofibular ligaments; and lateral gastrocnemius muscle. Injuries to lateral knee structures are less common than injuries to medial knee structures but may be more disabling. Most lateral compartment injuries are associated with damage to the cruciate ligaments and medial knee structures. Moreover, such injuries are frequently overlooked at clinical examination. Structures of the anterolateral quadrant are the most frequently injured; posterolateral instability is considerably less common. Practically all tears of the lateral collateral ligament are associated with damage to posterolateral knee structures. Most injuries of the popliteus muscle and tendon are associated with damage to other knee structures. MR imaging can demonstrate these injuries. Familiarity with the musculotendinous anatomy of the knee will facilitate accurate diagnosis with MR imaging.