The incidence of indeterminate pulmonary nodules has risen constantly over the past few years. Determination of lung nodule malignancy is pivotal, because the early diagnosis of lung cancer could lead to a definitive intervention. According to the current international guidelines, size and growth rate represent the main indicators to determine the nature of a pulmonary nodule. However, there are some limitations in evaluating and characterising nodules when only their dimensions are taken into account. There is no single method for measuring nodules, and intrinsic errors, which can determine variations in nodule measurement and in growth assessment, do exist when performing measurements either manually or with automated or semi-automated methods. When considering subsolid nodules the presence and size of a solid component is the major determinant of malignancy and nodule management, as reported in the latest guidelines. Nevertheless, other nodule morphological characteristics have been associated with an increased risk of malignancy. In addition, the clinical context should not be overlooked in determining the probability of malignancy. Predictive models have been proposed as a potential means to overcome the limitations of a sized-based assessment of the malignancy risk for indeterminate pulmonary nodules.

To systematically review and meta-analyze published data about the diagnostic performance of Fluorine-18-Fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) and PET/computed tomography (PET/CT) in patients with chronic inflammatory bowel disease (IBD). A comprehensive computer literature search of studies published through May 2012 regarding (18)F-FDG-PET and PET/CT in patients with IBD was performed. All retrieved studies were reviewed and qualitatively analyzed. Pooled sensitivity, specificity, positive and negative likelihood ratio (LR+ and LR-) and diagnostic odd ratio (DOR) of (18)F-FDG PET and PET/CT in patients with IBD on a per segment-based analysis were calculated. The area under the ROC curve was calculated to measure the accuracy of (18)F-FDG PET and PET/CT in patients with IBD. Nineteen studies comprising 454 patients with suspected IBD were included in the qualitative analysis (systematic review) and discussed. The quantitative analysis (meta-analysis) of seven selected studies (including 219 patients with IBD) provided the following results on a per segment-based analysis: sensitivity was 85% [95% confidence interval (95%CI) 81-88%], specificity 87% (95%CI 84-90%), LR+ 6.19 (95%CI: 2.86-13.41), LR- 0.19 (95%CI: 0.10-0.34), and DOR 44.35 (95%CI: 11.77-167.07). The area under the ROC curve was 0.933. In patients with suspected IBD (18)F-FDG PET and PET/CT demonstrated good sensitivity and specificity, being accurate methods in this setting. Nevertheless, the literature focusing on the use of PET and PET/CT in IBD remains still limited; thus, further large multicenter studies will be necessary to substantiate the diagnostic accuracy of these methods in patients with IBD.

The aims of this study were to investigate the added value of diffusion-weighted imaging (DWI) in pancreatic neuroendocrine tumor (pNET) evaluation and to compare magnetic resonance imaging (MRI) to 68Ga-DOTANOC positron emission tomography/computed tomography (PET/CT) results. Morphological MRI (T2-weighted [T2-w] + contrast-enhanced [CE] T1-w) and DWI (T2-w + DWI) and 68Ga-DOTANOC PET/CT in 25 patients/30 pNETs were retrospectively evaluated. Per-patient and per-lesion detection rates (pDR and lDR, respectively) were calculated. Apparent diffusion coefficient values were compared among pNET and surrounding and normal pancreas (control group, 18 patients). Apparent diffusion coefficient and standardized uptake value (SUV) values were compared among different grading and staging groups. No statistically significant differences in PET/CT and MRI session detection rates were found (morphological MRI and DW-MRI, 88% pDR and 87% lDR; combined evaluation, 92% pDR and 90% lDR; 68Ga-DOTANOC PET/CT, 88% pDR and 80% lDR). Consensus reading (morphological/DW-MRI + PET/CT) improved pDR and lDR (100%). Apparent diffusion coefficient mean value was significantly lower compared with surrounding and normal parenchyma (P < 0.01). The apparent diffusion coefficient and SUV values of pNETs among different grading and staging groups were not statistically different. Conventional MRI, DW-MRI + T2-w sequences, and 68Ga-DOTANOC PET/CT can be alternative tools in pNET detection. Diffusion-weighted MRI could be valuable in patients with clinical suspicion but negative conventional imaging findings. However, the consensus reading of the 3 techniques seems the best approach.

Diagnosis and treatment of locally advanced rectal cancer is mainly based on multimodal approach for staging, planning and treatment. The modern radiological and imaging techniques offer, day after day, the possibility to characterize tumor lesions in a more precise and prognostically valuable way. In rectal cancer, extending often the characterization to colon cancer, literature offers some evidences that quantitative and “radiomics” analysis of tumor images might improve the prognostic evaluation of the tumor and the patients’ characterization. Unfortunately, as in other fields of radiomics, the rise of new evidence and models based on single institution case series don’t offer the practical chance to apply them universal data set. Greater efforts in the direction of model evaluation and validation, above all using an external validation approach, are expected to be shown in the coming years for validation of methodology.