Hemangioma hepático subcapsular com realce perilesional: achados de RM

Perilesional enhancement of liver cavernous hemangiomas in magnetic resonance imaging

OBJECTIVE

To evaluate on magnetic resonance imaging (MRI) the occurrence rate of temporal perilesional parenchymal enhancement (PPE) associated with hepatic hemangiomas in a large consecutive series and to determine which aspects are associated with this observation.

MATERIALS AND METHODS

Institutional review board approved this retrospective study. A computerized search of the MRI database was performed for consecutive patients between January 2008 and January 2012. The study population included 513 liver hemangiomas in 224 patients (104 males and 120 females; mean age of 55.2 ± 13.5 years; age range 24-89 years). Two readers independently reviewed the frequency of PPE, size, speed of enhancement and location of each hemangioma. Marginal models with generalized estimating equation were used. Wald test was applied to verify if the model coefficients were significant.

RESULTS

80/513 (15.6%) hemangiomas showed PPE. The incidence of PPE was significantly higher (p < 0.05) in hemangiomas with Type1 speed of enhancement (51/80, 63.8%) than in those with Type2 or Type3. 66/80 (82.5%) hemangiomas with PPE were subcapsular (p < 0.05). Conversely, the majority (280/433, 64.7%) of hemangiomas without PPE were deep in location (p < 0.001). Lesser proportion of hemangiomas with PPE was located in segment IVa (p < 0.05).

CONCLUSION

PPE is not uncommonly seen along with hepatic hemangiomas. This appearance is most frequently observed in rapidly enhancing small lesions with a subcapsular location.

Effects of iodinated contrast agent, xylocaine and gadolinium concentration on the signal emitted in magnetic resonance arthrography: a samples study

Objective

To investigate the effects of dilution of paramagnetic contrast agent with iodinated contrast and xylocaine on the signal intensity during magnetic resonance arthrography, and to improve the paramagnetic contrast agent concentration utilized in this imaging modality.

Materials and Methods

Samples specially prepared for the study with three different concentrations of paramagnetic contrast agent diluted in saline, iodinated contrast agent and xylocaine were imaged with fast spin echo T1-weighted sequences with fat saturation. The samples were placed into flasks and graphical analysis of the signal intensity was performed as a function of the paramagnetic contrast concentration.

Results

As compared with samples of equal concentrations diluted only with saline, the authors have observed an average signal intensity decrease of 20.67% for iodinated contrast agent, and of 28.34% for xylocaine. However, the increased gadolinium concentration in the samples caused decrease in signal intensity with all the dilutions.

Conclusion

Minimizing the use of iodinated contrast media and xylocaine and/or the use of a gadolinium concentration of 2.5 mmol/L diluted in saline will improve the sensitivity of magnetic resonance arthrography.