Deep Learning on Bone Scintigraphy to Detect Abnormal Cardiac Uptake at Risk of Cardiac Amyloidosis.

BACKGROUND: Cardiac uptake on technetium-99m whole-body scintigraphy (WBS) is almost pathognomonic of transthyretin cardiac amyloidosis. The rare false positives are often related to light-chain cardiac amyloidosis. However, this scintigraphic feature remains largely unknown, leading to misdiagnosis despite characteristic images. A retrospective review of all WBSs in a hospital database to detect those with cardiac uptake may allow the identification of undiagnosed patients. OBJECTIVES: The authors sought to develop and validate a deep learning-based model that automatically detects significant cardiac uptake (Perugini grade ≥2) on WBS from large hospital databases in order to retrieve patients at risk of cardiac amyloidosis. METHODS: The model is based on a convolutional neural network with image-level labels. The performance evaluation was performed with C-statistics using a 5-fold cross-validation scheme stratified so that the proportion of positive and negative WBSs remained constant across folds and using an external validation data set. RESULTS: The training data set consisted of 3,048 images: 281 positives (Perugini grade ≥2) and 2,767 negatives. The external validation data set consisted of 1,633 images: 102 positives and 1,531 negatives. The performance of the 5-fold cross-validation and external validation was as follows: 98.9% (± 1.0) and 96.1% for sensitivity, 99.5% (± 0.4) and 99.5% for specificity, and 0.999 (SD = 0.000) and 0.999 for the area under the curve of the receiver-operating characteristic curves. Sex, age <90 years, body mass index, injection-acquisition delay, radionuclides, and the indication of WBS only slightly affected performances. CONCLUSIONS: The authors' detection model is effective at identifying patients with cardiac uptake Perugini grade ≥2 on WBS and may help in the diagnosis of patients with cardiac amyloidosis.

PET Imaging in Bladder Cancer: An Update and Future Direction.

Molecular imaging with positron emission tomography is a powerful tool in bladder cancer management. In this review, we aim to address the current place of the PET imaging in bladder cancer care and offer perspectives on potential future radiopharmaceutical and technological advancements. A special focus is given to the following: the role of [18F] 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography in the clinical management of bladder cancer patients, especially for staging and follow-up; treatment guided by [18F]FDG PET/CT; the role of [18F]FDG PET/MRI, the other PET radiopharmaceuticals beyond [18F]FDG, such as [68Ga]- or [18F]-labeled fibroblast activation protein inhibitor; and the application of artificial intelligence.

Behavior of general physicians about lung cancer screening in a French region hosting a pilot study.

INTRODUCTION: Lung cancer is the leading cause of cancer-related death in France and has a 5-year survival rate of 20%. Recent prospective randomized controlled trials revealed that lung cancer-specific mortality decreased in patients who underwent screening using low-dose chest computed tomography (low-dose CT). The DEP KP80 pilot study conducted in 2016 showed that an organized lung cancer screening campaign involving general practitioners was feasible. MATERIAL AND METHOD: We conducted a descriptive observational study of screening practices by sending a self-reported questionnaire to 1013 general practitioners practicing in the Hauts-de-France region. Our study's primary aim was to investigate the knowledge and practices of general practitioners in the Hauts-de-France region of France regarding lung cancer screening using low-dose CT. The secondary endpoint was to compare practices between general practitioners in the Somme department who had experience of experimental screening and their colleagues in the rest of the region. RESULTS: The response rate was 18.8% (190 completed questionnaires). Even though 69.5% of the physicians were unaware of the potential benefits of organized low-dose CT screening for lung cancer, 76% proposed screening tests for individual patients. Despite its proven ineffectiveness, chest radiography was still the most widely recommended screening modality. Half of the physicians stated that they had already prescribed chest CT to screen for lung cancer. Additionally, only 36.3% proposed chest CT screening for patients aged over 50 years with a history of more than 30 pack-years. The physicians working in the Somme department (61% had participated in the DEP KP80 pilot study) were more aware of low-dose CT as a screening modality, and offered it significantly more than their colleagues in the other departments (61.1% vs 13.4% p<0.01). All the physicians were in favor of an organized screening program. CONCLUSION: More than a third of general practitioners in the Hauts-de-France region offered for lung cancer screening using chest CT, although only 18% specified low-dose CT. Before an organized screening program can be set up, good practice guidelines must be made available about lung cancer screening.

Isotopic Radiolabeling of Crizotinib with Fluorine-18 for In Vivo Pet Imaging.

Crizotinib is a tyrosine kinase inhibitor approved for the treatment of non-small-cell lung cancer, but it is inefficient on brain metastases. Crizotinib is a substrate of the P-glycoprotein, and non-invasive nuclear imaging can be used to assess the brain penetration of crizotinib. Positron emission tomography (PET) imaging using fluorine-18-labeled crizotinib would be a powerful tool for investigating new strategies to enhance the brain distribution of crizotinib. We have synthesized a spirocyclic hypervalent iodine precursor for the isotopic labeling of crizotinib in a 2.4% yield. Because crizotinib is an enantiomerically pure drug, a chiral separation was performed to afford the (R)-precursor. A two-step radiolabeling process was optimized and automated using the racemic precursor to afford [18F](R,S)-crizotinib in 15 ± 2 radiochemical yield and 103 ± 18 GBq/µmol molar activity. The same radiolabeling process was applied to the (R)-precursor to afford [18F](R)-crizotinib with comparable results. As a proof-of-concept, PET was realized in a single non-human primate to demonstrate the feasibility of [18F](R)-crizotinib in in vivo imaging. Whole-body PET highlighted the elimination routes of crizotinib with negligible penetration in the brain (SUVmean = 0.1). This proof-of-concept paves the way for further studies using [18F](R)-crizotinib to enhance its brain penetration depending on the P-glycoprotein function.