Radiologic-Pathologic Correlation of Cardiac Tumors: Updated 2021 WHO Tumor Classification.

Cardiac tumors, although rare, carry high morbidity and mortality rates. They are commonly first identified either at echocardiography or incidentally at thoracoabdominal CT performed for noncardiac indications. Multimodality imaging often helps to determine the cause of these masses. Cardiac tumors comprise a distinct category in the World Health Organization (WHO) classification of tumors. The updated 2021 WHO classification of tumors of the heart incorporates new entities and reclassifies others. In the new classification system, papillary fibroelastoma is recognized as the most common primary cardiac neoplasm. Pseudotumors including thrombi and anatomic variants (eg, crista terminalis, accessory papillary muscles, or coumadin ridge) are the most common intracardiac masses identified at imaging. Cardiac metastases are substantially more common than primary cardiac tumors. Although echocardiography is usually the first examination, cardiac MRI is the modality of choice for the identification and characterization of cardiac masses. Cardiac CT serves as an alternative in patients who cannot tolerate MRI. PET performed with CT or MRI enables metabolic characterization of malignant cardiac masses. Imaging individualized to a particular tumor type and location is crucial for treatment planning. Tumor terminology changes as our understanding of tumor biology and behavior evolves. Familiarity with the updated classification system is important as a guide to radiologic investigation and medical or surgical management. ©RSNA, 2024 Supplemental material is available for this article.

Multimodality imaging of neurodegenerative disorders with a focus on multiparametric magnetic resonance and molecular imaging.

Neurodegenerative diseases afflict a large number of persons worldwide, with the prevalence and incidence of dementia rapidly increasing. Despite their prevalence, clinical diagnosis of dementia syndromes remains imperfect with limited specificity. Conventional structural-based imaging techniques also lack the accuracy necessary for confident diagnosis. Multiparametric magnetic resonance imaging and molecular imaging provide the promise of improving specificity and sensitivity in the diagnosis of neurodegenerative disease as well as therapeutic monitoring of monoclonal antibody therapy. This educational review will briefly focus on the epidemiology, clinical presentation, and pathologic findings of common and uncommon neurodegenerative diseases. Imaging features of each disease spanning from conventional magnetic resonance sequences to advanced multiparametric methods such as resting-state functional magnetic resonance imaging and arterial spin labeling imaging will be described in detail. Additionally, the review will explore the findings of each diagnosis on molecular imaging including single-photon emission computed tomography and positron emission tomography with a variety of clinically used and experimental radiotracers. The literature and clinical cases provided demonstrate the power of advanced magnetic resonance imaging and molecular techniques in the diagnosis of neurodegenerative diseases and areas of future and ongoing research. With the advent of combined positron emission tomography/magnetic resonance imaging scanners, hybrid protocols utilizing both techniques are an attractive option for improving the evaluation of neurodegenerative diseases.

Prostate Cancer-PET Imaging Update.

Prostate cancer is the most common non-dermatologic cancer in men, and one of the leading causes of cancer-related mortality. The incidence of prostate cancer increases precipitously after the age of 65 and demonstrates variable aggressiveness, depending on its grade and stage at diagnosis. Despite recent advancements in prostate cancer treatment, recurrence is seen in 25% of patients. Advancements in prostate cancer Positron Emission Tomography (PET) molecular imaging and recent United States Food and Drug Administration (FDA) approvals have led to several new options for evaluating prostate cancer. This manuscript will review the commonly used molecular imaging agents, with an emphasis on Fluorine-18 fluciclovine (Axumin) and PSMA-ligand agents, including their protocols, imaging interpretation, and pitfalls.

Fibroblast Activation Protein Inhibitor-Based Radionuclide Therapies: Current Status and Future Directions.

Metastatic malignancies have limited management strategies and variable treatment responses. Cancer cells develop beside and depend on the complex tumor microenvironment. Cancer-associated fibroblasts, with their complex interaction with tumor and immune cells, are involved in various steps of tumorigenesis, such as growth, invasion, metastasis, and treatment resistance. Prooncogenic cancer-associated fibroblasts emerged as attractive therapeutic targets. However, clinical trials have achieved suboptimal success. Fibroblast activation protein (FAP) inhibitor-based molecular imaging has shown encouraging results in cancer diagnosis, making them innovative targets for FAP inhibitor-based radionuclide therapies. This review summarizes the results of preclinical and clinical FAP-based radionuclide therapies. We will describe advances and FAP molecule modification in this novel therapy, as well as its dosimetry, safety profile, and efficacy. This summary may guide future research directions and optimize clinical decision-making in this emerging field.

Physicians' and midlevel providers' awareness of lifetime radiation-attributable cancer risk associated with commonly performed CT studies: relationship to practice behavior.

OBJECTIVE: The purpose of this study is to investigate emergency department (ED) providers' knowledge of the lifetime cancer risk attributable to radiation from commonly performed CT scans and its association with the ordering providers' risk-benefit analysis before ordering the examination. This study further explores factors that may influence a provider's selection of a particular diagnostic imaging study in an ED setting. MATERIALS AND METHODS: Sixty-seven ED providers at the University of Rochester Medical Center completed a multiple-choice questionnaire. The questions were derived to assess an individual provider's awareness of lifetime cancer risk attributable to radiation from a diagnostic CT scan of the abdomen or pelvis and the provider's behavior toward risk-benefit analysis before ordering the examination. The association between the questions and years since completion of clinical training was determined using the Spearman correlation test. Univariate logistic regression analysis was used for the same questions to predict the knowledge of lifetime cancer risk attributable to radiation. RESULTS: Fewer than 30% of ED providers possessed accurate knowledge of lifetime cancer risk attributable to radiation (p = 0.025). Providers with greater clinical experience, although lacking in the knowledge of lifetime cancer risk attributable to radiation, were more likely to consider patients' radiation dose history and to conduct a risk-benefit analysis and were less likely to order a CT scan unnecessarily. Clinical experience was negatively correlated with perceived unnecessary use of CT scans (p = 0.01). CONCLUSION: A large proportion of ED providers are unaware of the lifetime risk of carcinogenesis associated with commonly performed CT scans. Clinical experience, not knowledge of lifetime cancer risk attributable to radiation, is significantly associated with beneficial behavior toward the use of CT.

FDG-PET on the trail of an unsuspected primary malignancy in the breast.

Proper identification of the primary malignancy can radically alter clinical management for the patient's benefit. This is a report of an unsuspected primary breast cancer in a patient being worked up for presumptive lymphoma. Prior investigation of lymphedema in the left lower extremity found widespread lymphadenopathy on computed tomography imaging, leading to initial biopsy revealing adenocarcinoma of unknown primary. F-18 fluorodeoxyglucose PET/computed tomography altered management by localizing an F-18 fluorodeoxyglucose avid breast nodule, directing breast biopsy with specific immunohistochemical analysis for breast cancer lineage in metastatic adenocarcinoma. The patient responded well to breast cancer-targeted chemotherapy.

Pancreatic pseudocyst observed on F-18 FDG PET imaging.

A 72-year-old man with right lower lobe squamous cell carcinoma of the lung-status, post resection-and prostate carcinoma was referred for restaging with whole-body PET using F-18 FDG. PET images, in addition to the presence of moderate hypermetabolic activity seen in the left lower paratracheal and bilateral hilar regions, revealed a large hypometabolic space-occupying lesion in the abdomen. The appearance of this lesion was highly suggestive of a pancreatic pseudocyst. Further review of a CT scan performed 3 years ago confirmed the presence of a pancreatic pseudocyst. However, this information was not available to the nuclear medicine physician at the time of the PET examination.

FDG PET/CT manifestations of hematopoietic malignancies of the breast.

Hematopoietic malignancies that can be encountered in the breast include lymphoma, leukemia, and multiple myeloma/plasmacytoma. These are readily imaged via [18]F-fluorodeoxyglucose position emission tomography (PET)/computed tomography (CT) and can manifest as unilateral, bilateral, single, multiple, round/oval masses, or diffuse. These malignancies can occasionally mimic primary breast cancers. Conversely, benign conditions, such as the lactating breast can resemble hematopoietic malignancies of the breast. Although uncommon, familiarity with hematopoietic malignancies of the breast is important for proper interpretation of PET/CT. In this pictorial review, the PET/CT imaging features of patients with hematopoietic malignancies of the breast will be described, including pathology-proven cases of acute myelogenous leukemia, diffuse B-cell lymphoma, follicular lymphoma, acute myeloid leukemia with neutropenic granulocytic) sarcoma, and plasmacytoma. In addition, potential pitfalls will be discussed.