State-of-the-Art Hybrid Imaging of Neuroendocrine Neoplasms.

ABSTRACT: Neuroendocrine neoplasms (NENs) may be challenging to diagnose due to their small size and diverse anatomical locations. Hybrid imaging techniques, specifically positron emission tomography/computed tomography (PET/CT) and positron emission tomography/magnetic resonance imaging (PET/MRI), represent the current state-of-the-art for evaluating NENs. The preferred radiopharmaceuticals for NEN PET imaging are gallium-68 (68Ga) DOTA-peptides, which target somatostatin receptors (SSTR) overexpressed on NEN cells. Clinical applications of [68Ga]Ga-DOTA-peptides PET/CT include diagnosis, staging, prognosis assessment, treatment selection, and response evaluation. Fluorodeoxyglucose-18 (18F-FDG) PET/CT aids in detecting low-SSTR-expressing lesions and helps in patient stratification and treatment planning, particularly in grade 3 neuroendocrine tumors (NETs). New radiopharmaceuticals such as fluorine-labeled SSTR agonists and SSTR antagonists are emerging as alternatives to 68Ga-labeled peptides, offering improved detection rates and favorable biodistribution. The maturing of PET/MRI brings advantages to NEN imaging, including simultaneous acquisition of PET and MRI images, superior soft tissue contrast resolution, and motion correction capabilities. The PET/MRI with [68Ga]Ga-DOTA-peptides has demonstrated higher lesion detection rates and more accurate lesion classification compared to PET/CT. Overall, hybrid imaging offers valuable insights in the diagnosis, staging, and treatment planning of NENs. Further research is needed to refine response assessment criteria and standardize reporting guidelines.

Interleukin-19 induces angiogenesis in the absence of hypoxia by direct and indirect immune mechanisms.

Neovascularization and inflammation are independent biological processes but are linked in response to injury. The role of inflammation-dampening cytokines in the regulation of angiogenesis remains to be clarified. The purpose of this work was to test the hypothesis that IL-19 can induce angiogenesis in the absence of tissue hypoxia and to identify potential mechanisms. Using the aortic ring model of angiogenesis, we found significantly reduced sprouting capacity in aortic rings from IL-19(-/-) compared with wild-type mice. Using an in vivo assay, we found that IL-19(-/-) mice respond to vascular endothelial growth factor (VEGF) significantly less than wild-type mice and demonstrate decreased capillary formation in Matrigel plugs. IL-19 signals through the IL-20 receptor complex, and IL-19 induces IL-20 receptor subunit expression in aortic rings and cultured human vascular smooth muscle cells, but not endothelial cells, in a peroxisome proliferator-activated receptor-γ-dependent mechanism. IL-19 activates STAT3, and IL-19 angiogenic activity in aortic rings is STAT3-dependent. Using a quantitative RT-PCR screening assay, we determined that IL-19 has direct proangiogenic effects on aortic rings by inducing angiogenic gene expression. M2 macrophages participate in angiogenesis, and IL-19 has indirect angiogenic effects, as IL-19-stimulated bone marrow-derived macrophages secrete proangiogenic factors that induce greater sprouting of aortic rings than unstimulated controls. Using a quantitative RT-PCR screen, we determined that IL-19 induces expression of angiogenic cytokines in bone marrow-derived macrophages. Together, these data suggest that IL-19 can promote angiogenesis in the absence of hypoxia by at least two distinct mechanisms: 1) direct effects on vascular cells and 2) indirect effects by stimulation of macrophages.

Key Factors to Attract More U.S. Diagnostic Radiology Residents into the Field of Nuclear Medicine and Molecular Imaging: A National Survey.

RATIONALE AND OBJECTIVES: To understand the current state of radiology residents' exposure to nuclear medicine and molecular imaging (NM/MI), determine key factors that may attract more trainees into the field, and identify differentiating aspects between those specializing in NM/MI and those who are not. MATERIALS AND METHODS: An anonymous web-based survey was sent to contacts at all diagnostic radiology residency programs in the United States for dissemination to their residents, collecting information about trainees' NM/MI exposure during residency and factors that may attract them to NM/MI. RESULTS: A total of 198 trainees responded to the survey, 34 of whom plan on pursuing a career in NM/MI. Most trainees reported early exposure to NM/MI during residency; most (97.4%) reported ample exposure to general NM/MI and oncologic studies. Less than 3% of trainees reported adequate exposure to therapies, neurological applications, molecular imaging/research advances, and physics. Respondents reported a need for better quality education (38.9%) and exposure to mentors (28.8%) as ways to attract trainees to NM/MI. Routinely encountered clinical pathology was the most interesting for those specializing in NM/MI (29.4%), whereas lifestyle was the most attractive aspect of NM/MI for those not pursuing a career in the field (27.4%). NM/MI-associated research was the least attractive for those specializing in NM/MI (35.3%), while job market concerns was the least attractive aspect for those not specializing in NM/MI (37.2%). Trainees planning to specialize in NM/MI reported higher satisfaction with their orientation to NM/MI during their first clinical rotation compared to those who do not plan to specialize in the field (3.03/5.00 and 2.67/5.00, respectively, p = 0.04). CONCLUSION: This survey highlights several factors that training programs and national societies can target to improve interest in NM/MI among radiology residents. We found that optimized education initiatives, including improved orientation to the field, increased mentoring, and career opportunities are essential levers for recruiting radiology trainees into the NM/MI workforce.

Imaging Information Overload: Quantifying the Burden of Interpretive and Non-Interpretive Tasks for Computed Tomography Angiography for Aortic Pathologies in Emergency Radiology.

RATIONALE: Over the past decade, technological advances have provided new tools for radiologists. However, the effect of these technological advances on radiologist workload and detecting pathologies needs to be assessed. OBJECTIVE: The purpose of this study is to assess the workload, including non-interpretative tasks, associated with Computed Tomography Angiogram (CTA) of Aorta exams performed in the Emergency Department (ED) over a 10-year period and their relationship to detection of aortic pathology. MATERIALS AND METHODS: This is a retrospective analysis of CTAs of Aorta performed on adults with suspected acute aortic pathology within the ED at an academic level I quaternary care hospital from January 1, 2005, through December 31, 2015. Data assessed included (1) Interpretive tasks: total number of images, number of reformat series, number of radiology reports with positive aortic pathologies; and (2) Non-interpretative tasks: recommendations and documentation of verbal communication with requesting providers. Statistical analyses were performed to assess temporal trends of variables. P values less than 0.05 are considered significant. RESULTS: A total of 4368 examinations (mean age: 69.8, M/F: 56.8%/43.2%) were performed. Studies per year increased significantly from 2005 (n = 278) to 2007 (n = 445), but not significantly after. The number of images and reformat series per scan increased from 487 to 2819 and 6.4 to 13.7, respectively (both P-value < 0.01). The proportion of exams with aortic findings did not significantly change (28.1% in 2005 and 24.9% in 2015). However, The proportions of exams with verbal communication increased from 9.3% to 24.6% and with recommendations from 1.8% to 28.9% (both P-value < 0.01). CONCLUSION: During a 10-year period, CTAs performed in the ED for suspected aortic pathology were associated with a significant increase in images created, reformat series generated, recommendations, and verbal communications with ordering providers without a concomitant increase in the rate of aortic pathologies. To completely capture the complexities of CTA workloads, non-interpretive tasks such as radiologist recommendations and verbal communications should also be included.

Impact of Significant Coronary Artery Calcification Reported on Low-Dose Computed Tomography Lung Cancer Screening.

BACKGROUND: Coronary artery calcification (CAC) is a common and important incidental finding in low-dose computed tomography (LDCT) performed for lung cancer screening (LCS). The impact of these incidental findings on patient management is unclear. PURPOSE: The goals of our study were to determine the impact of reporting CAC on patient management and to determine whether standardized reporting of CAC affects the likelihood of future interventions. METHODS: In this IRB-approved retrospective study, we queried our LCS database for reports of LDCT performed between January 2016 and September 2018. All reports with significant findings of CAC designated with the letter "S" for any Lung-RADS category were selected. The grading of CAC was extracted from the reports. Medical records were reviewed for each patient to determine demographics, clinical history, medications, and cardiac-related diagnostic and interventional procedures. The changes in management after the report of significant CAC on LDCT were documented. Statistical analysis with Student t test and Pearson χ test was performed. RESULTS: A total of 756/3110 patients (mean age: 67±6.4 y; M=466, 61.6%: F=290, 38.4%) were reported to have significant CAC on LDCT for LCS. Of them, 236/756 patients (31.2%) had established coronary artery disease (CAD) at baseline, before the initial LDCT. A change in management was observed in 155/756 patients (20.5%). The most common changes in management included the following: alteration in medication regimen (n=114/155, 73.5%), stress testing (n=65/155, 41.9%), and referral to a cardiologist (36/155, 23.2%). Percutaneous coronary intervention (4, 2.6%) and surgery (3, 1.9%) were uncommon. Changes in management were more common in those without established CAD and in those whose CAC was semiquantitatively graded (35% vs. 25%, P=0.02). CONCLUSION: CAC is a common significant finding in LDCT for LCS. Reporting of CAC in patients with nonestablished CAD and semiquantitative assessment resulted in changes in management.

High-resolution CT, histopathologic, and clinical features of granulomatous pneumocystis jiroveci pneumonia.

Although pneumocystis jiroveci pneumonia was historically associated with HIV/AID patients, there is a recent shift in demographics with increasing incidence in patients with hematologic malignancies and transplants. A granulomatous response to pneumocytis jiroveci infection is uncommon and most commonly presents as multiple randomly distributed nodules on chest imaging. Granulomatous pneumocytis jiroveci pneumonia presents with similar clinical manifestations as typical pneumocytis pneumonia but is usually not detected by bronchoalveolar lavage and may require biopsy for a definitive diagnosis. For this reason, the radiologist may be the first provider to suggest this diagnosis and guide management.