Papel de la difusión en la evaluación de los meningiomas: correlación radiopatológica / The role of diffusion-weighted imaging in the evaluation of meningiomas: radio-pathologic correlation

Objetivo: Estudiar el comportamiento de los meningiomas en secuencias de difusión y su correlación histopatológica. Material y métodos: Se incluyeron prospectivamente pacientes operados de meningiomas durante 2 años en nuestro hospital. Se estudiaron 30 meningiomas en 28 pacientes entre 31 y 85 años. Todos los pacientes fueron estudiados en una unidad de resonancia magnética de 1,5T antes de la intervención, incluyendo imágenes potenciadas en difusión (IPD). La intensidad de señal se valoró en imágenes potenciadas en T2, IPD (b=1.000) y mapas del coeficiente de difusión aparente (CDA), dentro del tumor y en la sustancia blanca parietal como referencia. En el estudio histopatológico se analizaron la celularidad, el índice de proliferación, el grado histológico y la invasión cerebral. Resultados: De los 30 meningiomas, 22 fueron grado I de la Organización Mundial de la Salud y 8 atípicos o grado II. El valor medio del CDA fue 89.19±13,95×10–3mm2/s. En el grupo de meningiomas atípicos fue de 82±13,69×10–3mm2/s, y en el grupo de típicos de 92,21±13,21×10–3mm2/s. No se encontraron diferencias estadísticamente significativas entre los 2 grupos. Dos subtipos de meningiomas típicos, los secretores y el angiomatoso, presentaron los valores más altos en los mapas CDA. En el análisis histológico se observó una asociación significativa entre la celularidad tumoral y la señal en el mapa CDA. Conclusión: Los meningiomas presentan una restricción moderada de la difusión. La señal en el mapa CDA se asocia con la celularidad tumoral pero no se ha demostrado su utilidad para predecir el grado histológico (AU)

Objectives: To describe the ultrasonographic findings in liver abscesses after the administration of a second generation agent. To perform the differential diagnosis of liver abscesses with other focal liver lesions. Material and methods: We evaluated 28 liver abscesses in 5 patients before and after the administration of SonoVue. We also evaluated liver lesions in six patients in whom the differential diagnosis with liver abscess was considered in the baseline ultrasonographic examination. Results: A typical enhancement pattern consisting of peripheral ring enhancement in the arterial phase and absence of central enhancement was observed in 21 (75%) abscesses. In another 6 (21.4%) abscesses, arterial enhancement was seen in large areas of the lesion, while other areas showed no uptake. One case (3.6%) had a multiseptated pattern of enhancement. Segmental hepatic enhancement was observed in 6 abscesses. In the liver lesions in which the differential diagnosis with abscess was carried out, 5 of the 6 showed no enhancement in any phase. The other lesion, a cystic metastasis, had irregular peripheral enhancement in the arterial phase. None of these lesions had segmental hepatic enhancement in the arterial phase. Conclusions: Contrast administration improves the performance of ultrasonography in the diagnosis of liver abscesses. There are three patterns of enhancement and these correlate well with the findings at CT and MRI. Contrast-enhanced ultrasonography is very useful for defining the internal architecture of the abscess, which is important for choosing the type of treatment. Contrast-enhanced ultrasonography also enables the differential diagnosis with other focal liver lesions (AU)

[The role of diffusion-weighted imaging in the evaluation of meningiomas: radio-pathologic correlation]. / Papel de la difusión en la evaluación de los meningiomas: correlación radiopatológica.

OBJECTIVE: To study the behavior of meningiomas in diffusion-weighted sequences and the correlation of these findings with the histological findings. MATERIAL AND METHODS: We prospectively included all patients operated on for meningiomas at our hospital during two years. We studied 30 meningiomas in 28 patients aged 31 to 85 years old. All patients underwent MRI prior to surgery, including diffusion-weighted sequences, in a 1.5 T scanner. We evaluated the signal intensity in T2-weighted images, diffusion-weighted images (b=1,000), and apparent diffusion coefficient (ADC) maps within the tumor and in the parietal white matter as a reference. In the histological study, cellularity, proliferation index, histological grade, and cerebral invasion were evaluated. RESULTS: Of the 30 meningiomas, 22 were World Health Organization (WHO) grade I and 8 were atypical or WHO grade II. The overall mean value of the ADC was 89.19+/-13.95x10(-3) mm2/s; the mean ADC value was 82+/-13.69x10(-3) mm2/s in the atypical group and 92.21+/-13.21x10(-3) mm2/s in the typical group. No statistically significant differences were found between the 2 groups. Two subtypes of typical meningiomas, secretory and angiomatous meningiomas, had the highest values in the ADC maps. In the histological analysis, there was a significant association between tumor cellularity and the signal in the ADC map. CONCLUSION: Meningiomas show moderately restricted diffusion. The signal on the ADC map is associated with tumor cellularity but we have not demonstrated its usefulness for predicting the histological grade.