In atypical cirrhotic nodules, HB-phase hypointensity by itself is the strongest marker of malignancy.

This review aims to analyse the published data on the prevalence and clinical significance of breast incidental F18-FDG uptake detected by PET or PET/CT (BIU). A comprehensive computer literature search of the PubMed/MEDLINE, Scopus and Embase databases for studies on BIU published through July 2013 was performed. Pooled prevalence and malignancy risk of BIU were calculated. The literature search revealed 42 articles, and 17 were selected. One study was excluded because of data overlap but four additional studies were found screening the references. Finally, 20 articles were included in the systematic review and 13 were eligible for a meta-analysis. The pooled prevalence of BIU on all scans was 0.4 % (95 % CI 0.23-0.61 %), the pooled prevalence on scans on female patients only was 0.82 % (95 % CI 0.51-1.2 %), the pooled risk of malignancy of BIU when further analysed was 48 % (95 % CI 38-58 %) and the pooled risk of malignancy of BIU with histological examination was 60 % (95 % CI 53-66 %). The most frequent malignant lesion detected was infiltrating ductal carcinoma. Despite being rare, the identification of BIU frequently signals the presence of an unsuspected subclinical lesion, which differs from the indicated reason for which the patient was initially scanned, and the risk of malignancy is very high.

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Our results indicate that (11)C-choline PET/CT is a useful diagnostic tool in patients affected by prostate cancer and a relapsed PSA level. The highest accuracy for all patients is obtained with a PSA cutoff level of 1.26 ng/ml, above which the imaging study is performed (0.81 ng/ml for patients treated with surgery or surgery plus radiotherapy and 2.0 ng/ml for patients treated with radiotherapy alone).

Differentiated thyroid carcinoma (DTC) is a slow-growing tumor that represents 1% of all malignant tumors and is the most frequent endocrine cancer. ¹⁸F-Fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT) imaging is an increasingly important imaging tool in oncology and is still under investigation in numerous studies looking into its efficacy and cost-effectiveness. Despite the fact that ¹⁸F-FDG-PET/CT has been shown to be a powerful and accurate diagnostic tool in patients affected by DTC with high serum thyroglobulin (Tg) levels and negative radioiodine (¹³¹I) total body scan, its definitive role is not completely clear, in particular regarding the role of thyroid stimulating hormone (TSH) and Tg value "cutoff" over which is better to perform the study. In this review, these issues are analyzed to clarify controversial aspects and identify established cornerstones. In particular, the literature analysis suggests that levothyroxine withdrawal is preferable in cases of relatively low Tg levels (<10 ng/ml) and good clinical compliance to hypothyroidism. Moreover, recombinant thyrotropin stimulating hormone (rTSH) could be a preferable alternative in patients clinically unable to tolerate therapy withdrawal. A Tg cutoff level over which to perform the study seems to be 10 ng/ml, a reasonable value maintaining high accuracy in terms of a good compromise between sensitivity and specificity.