Ressonância magnética dos hemangiomas hepáticos: avaliação das características morfológicas e quantitativas

Abstract

INTRODUÇÃOHemangioma é o tumor hepático benigno mais comum, com incidência, em estudos de autópsias, variando entre 0,4% e 20%(1-3) , e sua diferenciação com tumores hepáticos malignos primários e secundá-rios é um dilema clínico comum. Na últi-ma década, a ressonância magnética (RM) se estabeleceu como método de imagem confiável na caracterização do hemangio- Magnetic resonance imaging of hepatic hemangiomas: morphologic and quantitative characteristics. OBJECTIVE: To evaluate the qualitative (morphological) and quantitative characteristics of hepatic hemangiomas with magnetic resonance imaging. MATERIAL AND METHODS: Twenty-seven patients with 57 hemangiomas were prospectively studied with magnetic resonance imaging using a system operating at 1.5 T. T1-and T2-weighted spin-echo images were obtained, including heavily T2-weighted images with TE of 160 ms. The morphological characteristics of the hemangiomas were studied and the lesions were classified as typical or atypical. Quantitative parameters (T2 relaxation time, simplified T2 index and lesion/liver signal intensity ratio) were also calculated. The values obtained for typical and atypical hemangiomas were compared as well as for the hemangiomas measuring ≤ 2.0 cm and > 2.0 cm. RESULTS: 78.9% of hemangiomas showed typical morphological features. There was no difference between the quantitative values for typical and atypical hemangiomas. There was not significant difference in T2 relaxation times and values of simplified T2 index in hemangiomas measuring ≤ 2.0 cm and > 2.0 cm. Lesion/liver signal intensity ratios showed significant differences between the two groups. T2 relaxation times, the simplified T2 index and the lesion/liver signal intensity ratios correctly characterized 96.5%, 93%, and 89.5% of the hemangiomas, respectively. CONCLUSION: Quantitative analysis of hepatic hemangiomas is a simple technique that in conjunction with morphological evaluation provides a more reliable characterization of these tumors. RESSONÂNCIA MAGNÉTICA DOS HEMANGIOMAS HEPÁTICOS: AVALIAÇÃO DAS CARACTERÍSTICAS MORFOLÓGICAS E QUANTITATIVAS*

Diferenciação entre cisto simples e hemangioma hepático utilizando seqüência de ressonância magnética ponderada em T2 com técnica gradiente-eco (B-FFE)

“…For this purpose, MRI was established as a golden-standard encompassing all the sequences adopted in the routine investigation of hepatic nodules, including contrast-enhanced sequences during arterial, portal venous and equilibrium phases (9) . This golden-standard has been utilized by the authors of the present study and by others, and also has been accepted in the literature as a reliable method for evaluating the effectiveness of new MRI sequences for detecting or characterizing hepatic nodules (6,12) . The results of the present study demonstrated that the b-FFE sequence is not only more effective than TSE with long TE, but also is more accurate, with a considerably high inter-observer agreement.…”

Neoplasias hepáticas: caracterização por métodos de imagem

“…hypervascular lesions such as focal nodular hyperplasia and some types of metastases presenting a more rapid wash-out pattern (7) . At MRI, hemangiomas are characterized by lesions with well-defined margins, hyperintense signal on T2-weighted sequences persisting with high echo times (around 180 ms) (2,5) . The gadolinium uptake pattern is similar to the iodinated contrast-mean uptake pattern found at CT (Figure 3).…”