Qualitative and Semiquantitative Parameters of 18F-FDG-PET/CT as Predictors of Malignancy in Patients with Solitary Pulmonary Nodule

This study aims to evaluate the reliability of qualitative and semiquantitative parameters of 18F-FDG PET-CT, and eventually a correlation between them, in predicting the risk of malignancy in patients with solitary pulmonary nodules (SPNs) before the diagnosis of lung cancer. A total of 146 patients were retrospectively studied according to their pre-test probability of malignancy (all patients were intermediate risk), based on radiological features and risk factors, and qualitative and semiquantitative parameters, such as SUVmax, SUVmean, TLG, and MTV, which were obtained from the FDG PET-CT scan of such patients before diagnosis. It has been observed that visual analysis correlates well with the risk of malignancy in patients with SPN; indeed, only 20% of SPNs in which FDG uptake was low or absent were found to be malignant at the cytopathological examination, while 45.45% of SPNs in which FDG uptake was moderate and 90.24% in which FDG uptake was intense were found to be malignant. The same trend was observed evaluating semiquantitative parameters, since increasing values of SUVmax, SUVmean, TLG, and MTV were observed in patients whose cytopathological examination of SPN showed the presence of lung cancer. In particular, in patients whose SPN was neoplastic, we observed a median (MAD) SUVmax of 7.89 (±2.24), median (MAD) SUVmean of 3.76 (±2.59), median (MAD) TLG of 16.36 (±15.87), and a median (MAD) MTV of 3.39 (±2.86). In contrast, in patients whose SPN was non-neoplastic, the SUVmax was 2.24 (±1.73), SUVmean 1.67 (±1.15), TLG 1.63 (±2.33), and MTV 1.20 (±1.20). Optimal cut-offs were drawn for semiquantitative parameters considered predictors of malignancy. Nodule size correlated significantly with FDG uptake intensity and with SUVmax. Finally, age and nodule size proved significant predictors of malignancy. In conclusion, considering the pre-test probability of malignancy, qualitative and semiquantitative parameters can be considered reliable tools in patients with SPN, since cut-offs for SUVmax, SUVmean, TLG, and MTV showed good sensitivity and specificity in predicting malignancy

Nuclear medicine imaging of lung cancer and esophagus cancer

Background: Somatostatin receptors (SSTRs) occur in cancer tissue, and 99mTc-depreotide is a labelled somatostatin receptor analogue, binding to SSTRs subtype 2, 3, and 5. Purpose: The general aim of the present thesis was to study somatostatin receptor scintigraphy (SSTRS) with 99mTc-depreotide in the diagnosis and characterization of cancers in the lung and oesophagus. Study I evaluated the diagnostic value of the SSTRS with 99mTc-depreotide in 99 patients with suspected lung cancer. The sensitivity to detect malignancy was 94%, and to detect lung cancer 98%. The specificity was calculated on two sets of data. When all cases are used, the specificity was 52%. If the 12 pneumonias are excluded, the specificity was 77%. Study II was performed on 19 patients with histologically proven non-small-cell lung cancer (NSCLC), where the expression of SSTR subtype 2 was looked for and found by immunochemical methods. The quantitative evaluation of 99mTc-depreotide was performed using region-of-interest analysis and includes tumour counts/cm3, background counts/cm3, and the ratio between tumour and background counts. SSTR subtype 2 expression was positively correlated to the degree of the tumour’s differentiation (p < 0.05). 99mTc-depreotide uptake in tumour cells did not correlate with tumour grade or SSTR subtype 2, MIB-1, or p53 expression. Study III showed the feasibility of imaging oesophageal carcinoma with SSTRS with 99mTc- depreotide and optimal time intervals for imaging. None of the 13 cancer-free Barrett’s oesophagus patients in this study showed an increased 99mTc-depreotide uptake. Study IV investigated the expression of SSTRs of subtype 2A, 2B, 3, and 5 in 28 patients with suspected oesophageal cancer, where expression was detected in small amount in adenocarcinoma and was absent in squamous cell carcinoma. There was no correlation between the 99mTc-depreotide uptake and the amount of SSTRs, and no correlation between the amount of SSTRs and the differentiation grade of the tumour. Conclusion: SSTRS with the labeled somatostatin receptor analogue 99mTc-depreotide has a very high sensitivity for detecting lung cancer. A negative scintigraphy strongly suggests a benign lesion, and the method is useful in decision making with respect to surgery. There is an expression of SSTRS subtype 2 in NSCLC with a positive correlation between tumour differentiation and presence of SSTR subtype 2. There is no correlation between 99mTc-depreotide uptake compared to tumour differentiation, presence of SSTR subtype 2, p53, or MIB-1, and SSTRS cannot be used as a prognostic factor in patients with lung cancer. SSTRS with 99mTc-depreotide of oesophageal cancer is feasible, but not suitable, for either screening or primary diagnosis, because of the method’s modest sensitivity. However, this method has a high specificity. The majority of patients with adenocancer of the oesophagus have a low amount of SSTRs, while most of the patients with squamous cell cancer do not have any of SSTRs

Diseases of the Chest, Breast, Heart and Vessels 2019-2022

This open access book focuses on diagnostic and interventional imaging of the chest, breast, heart, and vessels. It consists of a remarkable collection of contributions authored by internationally respected experts, featuring the most recent diagnostic developments and technological advances with a highly didactical approach. The chapters are disease-oriented and cover all the relevant imaging modalities, including standard radiography, CT, nuclear medicine with PET, ultrasound and magnetic resonance imaging, as well as imaging-guided interventions. As such, it presents a comprehensive review of current knowledge on imaging of the heart and chest, as well as thoracic interventions and a selection of "hot topics". The book is intended for radiologists, however, it is also of interest to clinicians in oncology, cardiology, and pulmonology