Emerging Role of [18F]FLT PET/CT in Lymphoid Malignancies: A Review of Clinical Results.

Fluorine-18 fluorodeoxyglucose ([18F]FDG) is nowadays the leading positron emission tomography (PET) tracer for routine clinical work-ups in hematological malignancies; however, it is limited by false positive findings. Notably, false positives can occur in inflammatory and infective cases or in necrotic tumors that are infiltrated by macrophages and other inflammatory cells. In this context, 3'-deoxy-3'-[18F]fluorothymidine ([18F]FLT) has been shown to be a promising imaging biomarker of hematological malignant cell proliferation. In this review, a total of 15 papers were reviewed to collect literature data regarding the clinical application of [18F]FLT PET/CT in hematological malignancies. This imaging modality seems to be a suitable tool for noninvasive assessment of tumor grading, also showing a correlation with Ki-67 immunostaining. Moreover, [18F]FLT PET/CT demonstrated high sensitivity in detecting aggressive lymphoma lesions, especially when applying a standardized uptake value (SUV) cutoff of 3. At baseline, the potential of [18F]FLT imaging as a predictive tool is demonstrated by the low tracer uptake in patients with a complete response. However, its use is limited in evaluating bone diseases due to its high physiological uptake in bone marrow. Interim [18F]FLT PET/CT (iFLT) has the potential to identify high-risk patients with greater precision than [18F]FDG PET/CT, optimizing risk-adapted therapy strategies. Moreover, [18F]FLT uptake showed a greater ability to differentiate tumor from inflammation compared to [18F]FDG, allowing the reduction of false-positive findings and making the first one a more selective tracer. Finally, FLT emerges as a superior independent predictor of PFS and OS compared to FDG and ensures a reliable early response assessment with greater accuracy and predictive value.

Prostate Cancer Biochemical Recurrence Resulted Negative on [68Ga]Ga-PSMA-11 but Positive on [18F]Fluoromethylcholine PET/CT.

For prostate cancer (PCa) biochemical recurrence (BCR), the primarily suggested imaging technique by the European Association of Urology (EAU) guidelines is prostate-specific membrane antigen (PSMA) positron emission tomography/computer tomography (PET/CT). Indeed, the increased detection rate of PSMA PET/CT for early BCR has led to a fast and wide acceptance of this novel technology. However, PCa is a very heterogeneous disease, not always easily assessable with the highly specific PSMA PET with around 10% of cases occuring without PSMA expression. In this paper, we present the case of a patient with PCa BCR that resulted negative on [68Ga]Ga-PSMA-11 PET/CT, but positive on [18F]Fluoromethylcholine (Choline) PET/CT.

Isthmus topography is a risk factor for persistent disease in patients with differentiated thyroid cancer.

AIM: The risk of differentiated thyroid cancer (DTC) recurrence is widely evaluated according to the 2015 ATA Risk Stratification System. Topography of malignant nodules has been previously reported as an additional risk factor but is not included in the ATA system. Thus, our study aimed to evaluate the relationship between DTC topography and response to initial therapy. PATIENTS AND METHODS: We enrolled 401 low- to intermediate-risk patients with DTC who had undergone thyroidectomy and radioiodine therapy. DTC topography was recorded and compared with the response to therapy as assessed 12 months after the end of therapy. RESULTS: Overall, 366/401 (91.3%) patients had an excellent response to initial therapy while 22/401 (5.5%) and 13/401 (3.2%) had incomplete biochemical or structural responses, respectively. Incomplete response occurred in 10/36 (27.8%), 5/125 (4.0%), and 4/111 (3.6%) patients whose unifocal malignant nodules were located in the isthmus, right lobe, or left lobe. Incomplete response was also observed in 4/54 (7.4%) and 12/75 (16%) patients carrying multifocal cancers in one or both lobes, respectively. Patients with isthmic cancer more frequently demonstrated incomplete response compared with those who had cancer in other locations (P = 0.00). No significant relationship was found with age, gender, maximum size of malignant nodule, Hashimoto's thyroiditis, vascular invasion, and extrathyroidal extension (P = 0.78, P = 0.77, P = 0.52, P = 0.19, P = 0.73, and P = 0.26, respectively). The risk of incomplete response was about 65% higher in patients with isthmic lesions compared with other patients (odds ratio = 6.725). A log-rank test demonstrated that disease-free survival (DFS) of patients with isthmic lesions was significantly shorter than that of other patients (P = 0.02). CONCLUSION: Our data show that isthmus topography of malignant thyroid nodules is a risk factor for having both persistent disease 12 months after primary treatment and reduced DFS.

BRAFV600E mutation is associated with increased prevalence of contralateral lymph-node metastases in low and low-to-intermediate risk papillary thyroid cancer.

OBJECTIVE: Papillary thyroid cancer (PTC) is the most common endocrine malignancy. Despite good prognosis being generally associated with PTC, persistent/recurrent disease can be observed in a not negligible number of patients. Accurate postoperative management can lead to a significant improvement of risk stratification/staging of PTC patients identifying those at higher risk of a more aggressive clinical course. Molecular tests were introduced at the beginning of the 2000s to improve PTC risk stratification. METHODS: We reviewed the records of 354/1185 patients affected by low or low-to-intermediate risk unilateral-PTC. In these patients, BRAFV600E mutation was looked for and 131-radioiodine therapy was performed 3 months after thyroid surgery. A radioiodine post-therapeutic imaging was obtained in all patients. RESULTS: BRAFV600E mutation was found in 170/354 PTC patients (female = 126). Forty-two out of 170 BRAFV600E mutation +ve patients (female = 27) had ipsilateral (n = 24) or contralateral (n = 18) loco-regional metastases at post-therapeutic imaging. Significant differences in terms of 2015 American Thyroid Association risk stratification, Hashimoto thyroiditis prevalence, tumor size, multifocality, disease staging and aggressive variant were observed between BRAFV600E mutation +ve and BRAFV600E mutation -ve patients (P ≤ 0.001;P = 0.001; P ≤ 0.001; P = 0.026; P ≤ 0.001; P ≤ 0.001). Interestingly, the prevalence of contralateral lymph-node metastases was significantly higher in BRAFV600E mutation +ve than BRAFV600E mutation -ve patients (18/42 vs. 2/22, respectively; P = 0.013). CONCLUSION: This study suggests that BRAFV600E mutation represents a significant risk factor for developing contralateral lymph-node metastases and confirms that BRAFV600E mutation is associated with more aggressive PTC features and a higher prevalence of metastatic disease also in low or low-to-intermediate-risk PTC patients.

Artificial Neural Networks in Cardiovascular Diseases and its Potential for Clinical Application in Molecular Imaging.

In medical imaging, Artificial Intelligence is described as the ability of a system to properly interpret and learn from external data, acquiring knowledge to achieve specific goals and tasks through flexible adaptation. The number of possible applications of Artificial Intelligence is also huge in clinical medicine and cardiovascular diseases. To describe for the first time in literature, the main results of articles about Artificial Intelligence potential for clinical applications in molecular imaging techniques, and to describe its advancements in cardiovascular diseases assessed with nuclear medicine imaging modalities. A comprehensive search strategy was used based on SCOPUS and PubMed databases. From all studies published in English, we selected the most relevant articles that evaluated the technological insights of AI in nuclear cardiology applications. Artificial Intelligence may improve patient care in many different fields, from the semi-automatization of the medical work, through the technical aspect of image preparation, interpretation, the calculation of additional factors based on data obtained during scanning, to the prognostic prediction and risk-- group selection. Myocardial implementation of Artificial Intelligence algorithms in nuclear cardiology can improve and facilitate the diagnostic and predictive process, and global patient care. Building large databases containing clinical and image data is a first but essential step to create and train automated diagnostic/prognostic models able to help the clinicians to make unbiased and faster decisions for precision healthcare.