Imaging of Lung Transplantation.

Lung transplantation is the only curative treatment for end-stage lung disease, which is caused by a wide variety of pathologies and encountered in a diverse range of patients. Potential recipients, as well as donors are carefully evaluated by imaging prior to transplant for contraindications to the transplant. After transplantation, recipients are imaged in the immediate, early, intermediate, and late periods for complications that may arise and require intervention. Radiography and computed tomography are the 2 most commonly used imaging modalities used to evaluate the chest after lung transplantation.

Don't skip a beat! Critical findings in imaging studies performed in adults with congenital heart disease.

With ongoing advances in both medical and surgical management, the population of adults with congenital heart disease (CHD) continues to grow each year and has surpassed the number of pediatric cases. These adult patients will present to adult emergency departments with increasing frequency. Adults with CHD are at increased risk of developing not only cardiovascular complications, such as aortic dissection and thromboemboli, but also abdominopelvic and neurologic processes at younger ages. These individuals are also more likely to develop less urgent but clinically significant complications including end-organ dysfunction, baffle leaks, or bleeding collateral vessels. Ultimately, imaging can play a critical role in determining the triage, diagnosis, and management of adult CHD patients. To accomplish this goal, radiologists must be able to distinguish acute and chronic complications of treated CHD from benign processes, including expected post-surgical changes or imaging artifacts. Radiologists also need to be familiar with the various long-term risks and complications associated with both treated and untreated forms of CHD, particularly those in adults with complex lesions.

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.

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.

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.

Comparison of 100-Kilovoltage Tin Filtration With Advanced Modeled Iterative Reconstruction Protocol to an Automated Kilovoltage Selection With Filtered Back Projection Protocol on Radiation Dose and Image Quality in Pediatric Noncontrast-Enhanced Chest Computed Tomography.

OBJECTIVE: The aim of the study was to compare effects of a 100-kilovoltage (kVp) tin filtration (Sn100kVp) with Advanced Modeled Iterative Reconstruction (ADMIRE) protocol to an automated kVp selection and filtered back projection (FBP) protocol on radiation dose and image quality of in noncontrast-enhanced pediatric chest computed tomography (CT). METHODS: This retrospective study included 55 children (12 ± 6 years) undergoing baseline imaging using automated kVp selection with FBP on a second-generation dual-source CT scanner and follow-up CT using Sn100kVp with ADMIRE on a third-generation dual-source CT scanner. The volume CT dose index, dose length product, size-specific dose estimate, and milliamperage were compared. Image quality was calculated using signal-to-noise ratio and subjectively evaluated by 2 radiologists. RESULTS: Mean volume CT dose index, dose length product, and size-specific dose estimate were lower for the Sn100kVp protocol with ADMIRE (0.83 ± 0.18 mGy, 21.9 ± 7.5 mGy × cm, 1.28 ± 0.24 mGy) compared with the automated kVp protocol with FBP (2.17 ± 1.10 mGy, 65.1 ± 41.1 mGy × cm, 3.25 ± 1.44 mGy, P < 0.001), whereas milliamperage was and subjective image quality were higher for Sn100kVp (P < 0.001). CONCLUSIONS: A Sn100kVp protocol with ADMIRE lowers dose while maintaining image quality in noncontrast-enhanced pediatric chest CT.

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.

Diagnostic and Imaging Approaches to Chest Wall Lesions.

Chest wall lesions are relatively uncommon and may be challenging once they are encountered on images. Radiologists may detect these lesions incidentally at examinations performed for other indications, or they may be asked specifically to evaluate a suspicious lesion. While many chest wall lesions have characteristic imaging findings that can result in an accurate diagnosis with use of imaging alone, other entities are difficult to distinguish at imaging because there is significant overlap among them. The interpreting radiologist should be familiar with the imaging features of both "do not touch" benign entities (which can be confidently diagnosed with imaging only, with no need for biopsy or resection unless the patient is symptomatic) and lesions that cannot be confidently characterized and thus require further workup. CT and MRI are the main imaging modalities used to assess the chest wall, with each having different benefits and drawbacks. Chest wall lesions can be classified according to their predominant composition: fat, calcification and ossification, soft tissue, or fluid. The identification or predominance of signal intensities or attenuation for these findings, along with the patient age, clinical history, and lesion location, can help establish the appropriate differential diagnosis. In addition, imaging findings in other organs, such as the lungs or upper abdomen, can at times provide clues to the underlying diagnosis. The authors review different chest wall lesions classified on the basis of their composition and highlight the imaging findings that can assist the radiologist in narrowing the differential diagnosis and guiding management. ©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.

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.

American Society of Emergency Radiology Multicenter Blunt Splenic Trauma Study: CT and Clinical Findings.

Background Treatment of blunt splenic trauma (BST) continues to evolve with improved imaging for detection of splenic vascular injuries. Purpose To report on treatments for BST from 11 trauma centers, the frequency and clinical impact of splenic vascular injuries, and factors influencing treatment. Materials and Methods Patients were retrospectively identified as having BST between January 2011 and December 2018, and clinical, imaging, and outcome data were recorded. Patient data were summarized descriptively, both overall and stratified by initial treatment received (nonoperative management [NOM], angiography, or surgery). Regression analyses were used to examine the primary outcomes of interest, which were initial treatment received and length of stay (LOS). Results This study evaluated 1373 patients (mean age, 42 years ± 18; 845 men). Initial treatments included NOM in 849 patients, interventional radiology (IR) in 240 patients, and surgery in 284 patients. Rates from CT reporting were 22% (304 of 1373) for active splenic hemorrhage (ASH) and 20% (276 of 1373) for contained vascular injury (CVI). IR management of high-grade injuries increased 15.6%, from 28.6% (eight of 28) to 44.2% (57 of 129) (2011-2012 vs 2017-2018). Patients who were treated invasively had a higher injury severity score (odds ratio [OR], 1.04; 95% CI: 1.02, 1.05; P < .001), lower temperature (OR, 0.97; 95% CI: 0.97, 1.00; P = .03), and a lower hematocrit (OR, 0.96; 95% CI: 0.93, 0.99; P = .003) and were more likely to show ASH (OR, 8.05; 95% CI: 5.35, 12.26; P < .001) or CVI (OR, 2.70; 95% CI: 1.64, 4.44; P < .001) on CT images, have spleen-only injures (OR, 2.35; 95% CI: 1.45, 3.8; P < .001), and have been administered blood product for fewer than 24 hours (OR, 2.35; 95% CI: 1.58, 3.51; P < .001) compared with those chosen for NOM, after adjusting for key demographic and clinical variables. After adjustment, factors associated with a shorter LOS were female sex (OR, 0.84; 95% CI: 0.73, 0.96; P = .009), spleen-only injury (OR, 0.72; 95% CI: 0.6, 0.86; P < .001), higher admission hematocrit (OR, 0.98; 95% CI: 0.6, 0.86; P < .001), and presence of ASH at CT (OR, 0.74; 95% CI: 0.62, 0.88; P < .001). Conclusion Contained vascular injury and active splenic hemorrhage (ASH) were frequently reported, and rates of interventional radiologic management increased during the study period. ASH was associated with a shorter length of stay, and patients with ASH had eight times the odds of undergoing invasive treatment compared with undergoing nonoperative management. © RSNA, 2021 See also the editorial by Patlas in this issue.

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.

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.

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.