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[The tissue characterization of focal liver lesions with magnetic resonance imaging]
R Manfredi1, G Maresca, A M De Gaetano
1Istituto di Radiologia, Università Cattolica del Sacro Cuore, Policlinico A. Gemelli, Roma.
Abstract:
This study was aimed at assessing the accuracy of Magnetic Resonance Imaging (MRI) in the characterization of focal liver masses. We prospectively examined 51 patients with focal liver masses: the morphological features were investigated with different pulse sequences and the functional characteristics were studied after the i.v. administration of Gd-DTPA (2 mmol/kg). MR findings were compared with those of gold standard methods, i.e., percutaneous biopsy, surgery or, for hemangiomas, 99mTc-labelled blood cell liver scintigraphy. All hemangiomas presented with typical features: signal intensity was very high on long TE images (> 140 msec) and a globular enhancement pattern, with centripetal progression, was observed after dynamic studies. This signal pattern on T2-weighted images is highly indicative of hemangioma. Five of 7 focal nodular hyperplasias (71%) were isointense with hepatic parenchyma on all pulse sequences; the central scar was observed in 5/7 cases on short TR/TE images and in all cases on long TR/TE images in 16/17 cases (94%). High signal intensity on T1-weighted images was statistically significant for HCC. A pseudocapsule was observed in 12 cases (70%). A mosaic pattern on T2-weighted images was observed in 3 cases. Seventy-four per cent of HCCs exhibited signal enhancement during the arterial phase of the dynamic study. Metastases presented a uniform pattern, i.e., they were hypointense on T1-weighted and hyperintense on T2-weighted images in 12/13 cases (92%). A central hypointense area on T2-weighted images is indicative of coagulative necrosis. A lesion with these morphological features and hypovascular signal is suggestive of metastasis.
Insights
Magnetic Resonance Imaging (MRI) accurately characterizes focal liver masses by analyzing morphological and functional features. This study confirms MRI
Area of Science:
- Radiology
- Medical Imaging
- Hepatology
Background:
- Accurate characterization of focal liver masses is crucial for effective patient management.
- Magnetic Resonance Imaging (MRI) offers advanced visualization of liver lesions.
- Distinguishing between benign and malignant liver tumors impacts treatment strategies.
Purpose of the Study:
- To assess the diagnostic accuracy of Magnetic Resonance Imaging (MRI) in characterizing focal liver masses.
- To correlate MRI findings with histopathological diagnoses.
- To evaluate the utility of different MRI sequences and contrast enhancement patterns.
Main Methods:
- Prospective study of 51 patients with focal liver masses.
- Utilized various MRI pulse sequences for morphological assessment.
- Administered intravenous Gadolinium-DTPA contrast for functional analysis.
- Compared MRI results with gold standard diagnostic methods (biopsy, surgery, scintigraphy).
Main Results:
- Hemangiomas showed characteristic high signal intensity on T2-weighted images and globular enhancement.
- Focal nodular hyperplasias often presented as isointense lesions with visible central scars.
- Hepatocellular carcinoma (HCC) demonstrated significant high signal intensity on T1-weighted images.
- Metastases typically appeared hypointense on T1 and hyperintense on T2, sometimes with central necrosis.
Conclusions:
- MRI is a highly accurate imaging modality for characterizing focal liver masses.
- Specific MRI features can reliably differentiate between hemangiomas, focal nodular hyperplasias, HCC, and metastases.
- MRI findings, combined with contrast dynamics, aid in non-invasive tumor diagnosis.