The purpose of this study was to compare diffusion-weighted respiratory-triggered single-shot spin echo echoplanar imaging (SS SE-EPI) sequence using four b-values (b = 0, b = 20, b = 300, b = 800 s mm(-2)) and single-shot T2 weighted turbo spin echo (T2W SS TSE) in patients with focal liver lesions, with special interest in small (<10 mm) lesions. Twenty-four patients underwent routine MRI. The five sequences were compared qualitatively for image quality, lesion conspicuity and artefacts. Quantitative analysis was performed for lesion identification and lesion-to-liver contrast-to-noise ratio (CNR). Subgroup analyses were performed for different types of lesions with different sizes. Sequences were compared by rank order statistic (RIDIT) and Kruskal-Wallis test. The best image quality (p<0.05) was achieved with T2W TSE and the best lesion conspicuity (p<0.05) with T2W TSE for biliary cysts and SE-EPI diffusion-weighted imaging (DWI) (b = 20 s mm(-2)) for haemangiomas and metastases. Image artefacts were lowest (p<0.05) with T2W TSE. T2W TSE was found to be the best protocol (p<0.05) for the identification of biliary cysts and SE-EPI DWI (b = 20 s mm(-2)) for haemangiomas and metastases. The lesion-to-liver CNRs were highest on T2W TSE for biliary cysts and on SE-EPI diffusion-weighted imaging (DWI) for haemangiomas and metastases (p<0.05). This study shows the potential of SS SE-EPI DWI (especially with a b-value of 20 s mm(-2)) as a promising technique for detecting small (<10 mm) focal liver lesions.

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Endothelial IDO expression is highly consistent in primary, sentinel and metastatic tissues of patients with melanoma, indicating that immune suppression in melanoma is determined very early in the disease course. This supports that IDO expression in melanoma is a marker of antitumour immune response with an independent prognostic value.

Rosettes are an optical effect of crossed polarization by concentric fibrosis or horny material and hence are not lesion-specific.

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