Chemotherapy-Induced Toxicities: An Imaging Primer[Formula: see text].

The Coronavirus Disease of 2019 (COVID-19) pandemic has caused significant delays in the delivery of cancer treatments in Canada. As cancer treatment and imaging volumes return to normal, radiologists will encounter more cases of chemotherapy-induced toxicities. These toxicities have varied appearances on imaging, and can affect multiple organ systems. The purpose of this review is to offer a unified resource for general radiologists regarding the imaging appearances of chemotherapy-induced toxicities.

CT Appearance of Pulmonary Arteriovenous Malformations and Mimics.

A pulmonary arteriovenous malformation (PAVM) is a fistulous connection between a pulmonary artery and a pulmonary vein that bypasses the normal pulmonary capillary bed resulting in a right-to-left shunt. Because of the potential for paradoxical emboli, PAVMs are treated when their feeding arteries exceed 3 mm or patients are symptomatic. PAVMs are often encountered in patients with suspected hereditary hemorrhagic telangiectasia (HHT). Sporadic cases are uncommon. The radiologist may be called on to diagnose a PAVM after positive transthoracic contrast-enhanced echocardiography in a patient with suspected HHT to direct patient management and avoid potential complications. The radiologist may also be required to evaluate a potential PAVM detected at CT performed for other reasons. Through the authors' experiences at an HHT Center of Excellence in an area endemic with histoplasmosis, the authors have gained a unique perspective on the diagnosis of PAVMs and differentiation of PAVMs from their mimics. Understanding the CT appearance of PAVMs limits misdiagnosis, directs appropriate treatment, and allows subsequent family screening for HHT (and avoidance of unnecessary screening when a PAVM mimic is encountered). Both vascular and nonvascular pulmonary lesions can mimic PAVMs. Vascular mimics include fibrosing mediastinitis, venovenous collaterals, arterial collaterals, pulmonary artery pseudoaneurysms, hepatopulmonary vessels, Sheehan vessels, meandering pulmonary veins, and pulmonary vein varices. Nonvascular mimics include granulomas, nodules, mucoceles, bronchoceles, ground-glass opacities, and atelectasis. The authors review the CT technique for evaluating PAVMs and the appearance of PAVMs and their mimics. ©RSNA, 2022.

CT of Postoperative Repair of the Ascending Aorta and Aortic Arch.

While many of the classic open surgical repairs are still used to repair the ascending aorta, management of the aortic arch has become more complex via implementation of newer open surgical and endovascular techniques. Furthermore, techniques are often combined in novel repairs or to allow extended anatomic coverage. As such, a framework that rests on understanding the expected postoperative appearance is necessary for the diagnostic radiologist to best interpret CT studies in these patients. After reviewing the imaging appearances of the common components used in proximal aortic repair, the authors present a structured approach that focuses on the key relevant questions that diagnostic radiologists should consider when interpreting CT studies in these patients. For repair of the ascending aorta, this includes determining whether the aortic valve has been repaired, whether the sinuses of Valsalva have been repaired, and how the coronary arteries were managed, when necessary. In repairs that involve the aortic arch, the relevant considerations relate to management of the arch vessels and the distal extent of the repair. In focusing on these questions, the diagnostic radiologist will be able to identify and describe the vast majority of repairs. Understanding these questions will also facilitate improved understanding of novel repairs, which often use these basic building blocks. Finally, complications-which typically involve infection, noninfectious repair breakdown, hemorrhage, problems with endografts, or disease of the remaining adjacent aorta-will be identifiable as deviations from the expected postoperative appearance. Online supplemental material is available for this article. ©RSNA, 2021.

CT of Gastric Volvulus: Interobserver Reliability, Radiologists' Accuracy, and Imaging Findings.

OBJECTIVE: The objective of this study was to identify CT findings and determine interobserver reliability of surgically proven gastric volvulus. MATERIALS AND METHODS: This single-center retrospective study included 30 patients (21 women, nine men; mean age, 73 years old) with surgically proven gastric volvulus who underwent preoperative CT and 31 age- and sex-matched control subjects (21 women, nine men; mean age, 74 years old) with large hiatal hernias who were imaged for reasons other than abdominal pain. Two blinded radiologists reviewed the CT images and recorded findings of organoaxial and mesenteroaxial gastric volvulus and ischemia. Interobserver reliability, reader accuracy, sensitivity, specificity, and likelihood ratios of each CT finding were calculated. RESULTS: The radiologists were overall 90% accurate (55/61; six false-negatives per reader) in identifying gastric volvulus. Interobserver agreement was substantial (κ = 0.71) for identifying the presence or absence of gastric volvulus. Agreement for most CT findings of gastric volvulus (11/14, 79%) was excellent (5/14, 36%) or substantial (6/14, 43%); the remaining findings showed moderate agreement (3/14, 21%). The most frequent and sensitive CT findings of volvulus with high positive likelihood ratios were stenosis at the hernia neck (reader 1, sensitivity = 80%, positive likelihood ratio = 26.66; reader 2, sensitivity = 77%, positive likelihood ratio = 12.83) and transition point at the pylorus (reader 1, sensitivity = 80%, positive likelihood ratio = 17; reader 2, sensitivity = 70%, positive likelihood ratio = 15). The presence of perigastric fluid or a pleural effusion were significantly more frequent in patients with ischemia at surgical pathology (p < 0.05 in all comparisons, both radiologists). CONCLUSION: In our series, CT showed substantial interobserver agreement and fair accuracy in identifying the presence of gastric volvulus.

Transcatheter Aortic Valve Replacement: Alternative Access beyond the Femoral Arterial Approach.

Aortic stenosis is the most prevalent valvular cardiovascular disease affecting the population over the age of 65 years. Transcatheter aortic valve replacement (TAVR) was developed as a minimally invasive surgical intervention to treat aortic stenosis in patients at high risk for surgical complications. Although the most commonly used approach for placement of a transcatheter aortic valve is in retrograde fashion via a transfemoral approach, narrowed luminal diameters, extensive atherosclerotic disease, or significant tortuosity may limit use of this route. In these patients, alternative methods including subclavian, transaortic, and transapical approaches should be considered. An understanding of these access routes and their respective indications and contraindications allows the radiologist to provide additional preprocedure measurements and images to help guide placement of the valve. ©RSNA, 2018.

In-Phase and Opposed-Phase Imaging: Applications of Chemical Shift and Magnetic Susceptibility in the Chest and Abdomen.

An earlier incorrect version appeared online. This article was corrected on December 17, 2018.

Abnormalities of the Coronary Arteries in Children: Looking beyond the Origins.

Coronary arterial abnormalities are uncommon findings in children that have profound clinical implications. Although anomalies of the coronary origins are well described, there are many other disease processes that affect the coronary arteries. Immune system-mediated diseases (eg, Kawasaki disease, polyarteritis nodosa, and other vasculiditides) can result in coronary arterial aneurysms, strictures, and abnormal tapering of the vessels. Because findings at imaging are an important component of diagnosis in these diseases, the radiologist's understanding of them is essential. Congenital anomalies may present at varying ages, and findings in hemodynamically significant anomalies, such as fistulas, are key for both diagnosis and preoperative planning. Pediatric heart surgery can result in wide-ranging postoperative imaging appearances of the coronary arteries and also predisposes patients to a multitude of complications affecting the heart and coronary arteries. In addition, although rare, accidental trauma can lead to injury of the coronary arteries, and awareness and detection of these conditions are important for diagnosis in the acute setting. Patients with coronary arterial conditions at presentation may range from being asymptomatic to having findings of myocardial infarction. Recognition of the imaging findings is essential to direct appropriate treatment. ©RSNA, 2017.

Imaging of trauma in the pregnant patient.

The pregnant trauma patient presents an important and challenging encounter for the clinical team and radiologist. In this article, we present several key aspects of the imaging workup of pregnant trauma patients, beginning with a review of the modalities that are used in this setting. Ultrasonography plays an important role in initial evaluation of the fetus but a limited role in evaluation of maternal injuries. Given that conventional radiography and computed tomography are the "workhorse" modalities for evaluation of pregnant trauma patients, radiologists must pay particular attention to radiation dose concerns. Magnetic resonance imaging can be used after the initial evaluation and for follow-up imaging, and safety concerns related to its use in pregnant patients are addressed. At imaging interpretation, radiologists must contend not only with the typical spectrum of injuries that can be seen in any trauma patient but also with pregnancy-specific injuries, such as placental abruption and uterine rupture. Particularly unusual situations, such as a ruptured ectopic pregnancy in a trauma patient, are presented. Although pregnant trauma patients are infrequently encountered, familiarity with imaging findings of injuries in these patients is essential to providing the best care for the mother and fetus.

Enhancing the Interpretation of Unenhanced Abdominopelvic CT.

Unenhanced abdominopelvic CT is frequently performed in patients who are critically ill or have contraindications to intravenous contrast. These cases can be challenging to interpret for the radiologist. Attention to CT physics and care in optimizing image viewing through techniques such as windowing can maximize diagnostic yield. In this case-based review, we will discuss the CT physics concepts of attenuation, common indications and reasons for unenhanced abdominopelvic CT, and review its utility through a series of illustrative cases.

Impact of Pretransplantation CT on Liver Donation in Potential Deceased Organ Donors.

BACKGROUND: Computed tomography (CT) is routinely used to determine the suitability of potential living donor liver transplants, providing important information about liver size, vascular anatomy, and the presence of other diseases that would preclude it from safe donation. CT is not routinely used, however, when evaluating eligible deceased organ donors after brain death, a group which comprises most orthotopic liver transplants. After the installation of a CT scanner at a local procurement facility, CTs have been performed on potential deceased organ donors and used, in conjunction with other evaluative protocols, to help direct donation decisions and assist in procurement procedures. STUDY DESIGN: A retrospective analysis of data from 373 cases spanning 5 years was systematically collected and analyzed, including information pertaining to patient's medical histories, biopsy results, operative findings, and CT results. RESULTS: CT findings directly impacted the directive decision-making process in 29% of cases in this patient cohort, likely an underestimate, and reliably evaluated important factors including variant vascular anatomy and the presence and severity of hepatic steatosis and cirrhosis. CONCLUSION: Overall, this study suggests that CT has the potential to play a significant role in procurement procedures and the directive decision-making process, thereby improving the efficiency and accuracy by which potential deceased organ donors are evaluated.

Sarcoidosis Mimicking Primary Pulmonary Artery Sarcoma.

ABSTRACT: A 71-year-old man with coronary artery disease, sarcoid uveitis, and recurrent ventricular tachycardia treated with implantable cardioverter-defibrillator presented with increasing dyspnea for several months. Echocardiography showed a large echogenic mass causing severe narrowing of the proximal main pulmonary artery and a resultant gradient of 65 mm Hg. Ventilation-perfusion scintigraphy showed diffusely decreased perfusion of the left lung and an additional mismatched segmental perfusion defect in the left upper lobe. Cardiac MRI could not be performed because of the implantable cardioverter-defibrillator.

Acute myocarditis after a second dose of the mRNA COVID-19 vaccine: a report of two cases.

We report two cases of myocarditis, in two young and previously healthy individuals, temporally related to the second dose of the mRNA-COVID-19 vaccine. Both patients developed acute chest pain, changes on electrocardiogram (ECG), and elevated serum troponin within two days of receiving their second dose. Cardiac magnetic resonance (CMR) findings were consistent with acute myocarditis.

Fluid-filled Cystic Lesions of the Lungs.

A pulmonary cyst usually refers to an air-filled space with a smooth, thin wall. Fluid-filled cystic lesions of the lungs include a range of etiologies such as true cysts, congenital malformations, infections, and benign and malignant neoplasms. With relatively little solid component, these lesions often have similar imaging appearances to one another. This article focuses on key imaging features and clinical characteristics that can be used to narrow the differential diagnosis.

Imaging Approach to Misplaced Central Venous Catheters.

Central venous catheters (CVCs) are commonly used in patients in a variety of clinical settings, including the intensive care unit, general ward, and outpatient settings. After placement, the radiologist is frequently requested to evaluate the location of CVCs and deem them suitable for use. An understanding of the ideal location of catheter tips as well as the approach to identifying malpositioned catheter tips is essential to prevent improper use, recognize and/or prevent further injury, and direct potential lifesaving care. An approach to CVC placement based on tip location can be helpful in localization and guiding management.

Computed Tomographic Imaging of Cardiac Trauma.

Cardiac injury can occur in the setting of blunt and penetrating trauma resulting in significantly adverse clinical outcomes. Although the clinical presentation is variable and computed tomographic imaging is rarely performed to specifically evaluate for cardiac injury, the ability to recognize the findings of cardiac injury on computed tomographic examinations performed for thoracic trauma is essential to avoid misdiagnosis and direct potentially lifesaving interventions. This article reviews the direct and indirect computed tomographic findings of cardiac injury.

3D Printing Provides a Precise Approach in the Treatment of Tetralogy of Fallot, Pulmonary Atresia with Major Aortopulmonary Collateral Arteries.

Patients with tetralogy of Fallot, pulmonary atresia, and multiple aortopulmonary collateral arteries (Tet PA MAPCAs) have a wide spectrum of anatomy and disease severity. Management of these patients can be challenging and often require multiple high-risk surgical and interventional catheterization procedures. These interventions are made challenging by complex anatomy that require the proceduralist to mentally reconstruct three-dimensional anatomic relationships from two-dimensional images. Three-dimensional (3D) printing is an emerging medical technology that provides added benefits in the management of patients with Tet PA MAPCAs. When used in combination with current diagnostic modalities and procedures, 3D printing provides a precise approach to the management of these challenging, high-risk patients. Specifically, 3D printing enables detailed surgical and interventional planning prior to the procedure, which may improve procedural outcomes, decrease complications, and reduce procedure-related radiation dose and contrast load.

Cardiac Positron Emission Tomography-Magnetic Resonance Imaging: Current Status and Future Directions.

Simultaneous acquisition positron emission tomography-magnetic resonance imaging (PET-MRI) has the ability to combine anatomic information derived from cardiac MRI with quantitative capabilities of cardiac PET and MRI and the promise of molecular imaging by specific PET tracers. This combination of cardiac PET and MRI delivers a robust and comprehensive clinical examination. It has the potential to assess various cardiovascular conditions, including assessment of myocardial ischemia, infarction, and function, as well as specific characterization of inflammatory and infiltrative heart diseases such as cardiac sarcoid and amyloid. It also offers fascinating possibilities in imaging other cardiovascular-related disease states, such as tumor imaging and vascular imaging. In this review, we begin with a general overview of the potentials of PET-MRI in cardiovascular imaging, followed by a discussion of the technical challenges unique to cardiovascular PET-MRI. We then discuss PET-MRI in various cardiovascular disease imaging applications. Potential limitations of PET-MRI and future directions are also considered.