NASCI case of the month: extensive ascending aortic graft infection with underlying chronic sternal osteomyelitis-a rare and high-risk complication.

Thoracic aortic graft infections are infrequent yet grave complications of cardiovascular surgery. Risk factors include prolonged operative time, postoperative wound infections, and patient-specific risk factors like diabetes or malnutrition (Van Hemelrijck et al., Vessel Plus 6:47, 2022). In postoperative vascular scenarios, it is critical to utilize cross-sectional imaging to detect the presence of a complication, followed by describing the morphology, extent, and ancillary features. FDG-PET/CT can help differentiate between expected postoperative changes and worrisome infection by metabolic activity (FDG uptake). We present an extensive case of ascending aortic graft infection in the setting of ongoing sternal osteomyelitis. CT and PET/CT reveal chronic sternal osteomyelitic changes spreading into the retrosternal soft tissues, and a large intraluminal thrombus in the ascending aortic graft. Small mobile strands propagate toward the right brachiocephalic origin, posing a significant stroke risk. PET/CT confirmed postoperative infection by demonstrating increased FDG uptake.

Resection of a Solitary Right Ventricular Metastasis in Oligorecurrent Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC), constituting the predominant manifestation of liver cancer, stands as a formidable medical challenge. The prognosis subsequent to surgical intervention, particularly for individuals presenting with a solitary tumor, relies heavily on the degree of invasiveness. The decision-making process surrounding therapeutic modalities in such cases assumes paramount importance. This case report illuminates a rather unusual clinical scenario. Here, we encounter a patient who, following a disease-free interval, manifested an atypical presentation of HCC, specifically, a solitary cardiac metastasis. The temporal interval of remission adds an additional layer of complexity to the case. Through a multidisciplinary planning process, the decision was made for surgical removal of the metastatic tumor.

Clinical Impact of Cardiac Fibromas.

Cardiac fibromas are rare primary tumors that can cause significant morbidity and mortality. There has not been a large clinical case review since 1994. This study provides an updated analysis of clinical impact, thereby enhancing understanding, increasing awareness, and revealing important factors in the diagnosis and management of cardiac fibromas. A retrospective case series was conducted at a tertiary care institution by reviewing radiology, surgical and pathology archives (1964 to 2020). Cases were included if cardiac fibroma was diagnosed through imaging or pathology. Demographics, symptomatology, electrophysiologic data, radiographic findings, pathology, interventions, and outcomes were examined. A total of 26 patients with cardiac fibromas were identified, including 12 women. The median age was 20.5 years (0 days to 72 years). Symptoms included palpitations (commonly due to ventricular tachycardia, 31%), syncope (15%), angina (15%), heart failure (12%), emboli (4%), and murmur (27%). One patient had Gorlin syndrome. A total of 22 patients were diagnosed through imaging, 15 of whom were biopsy-confirmed. A total of 9 patients were initially observed. A total of 2 eventually had surgery, 1 was lost to follow-up, 3 were asymptomatic, 1 had heart failure and atrial fibrillation, and 1 had atrial fibrillation and tachy-brady syndrome, requiring ablation and pacemaker placement. A total of 19 underwent resection. A total of 4 required complex operations, 1 required a second resection, and 1 operative death occurred. In conclusion, cardiac fibromas primarily affect the pediatric population; however, this study demonstrates a significant prevalence in adults. Ventricular tachycardia is common, and multimodality imaging is diagnostically sensitive. Resection is largely successful in symptomatic patients. Surveillance may be appropriate for asymptomatic patients.

ACR Appropriateness Criteria® Dyspnea-Suspected Cardiac Origin (Ischemia Already Excluded): 2021 Update.

Dyspnea is the symptom of perceived breathing discomfort and is commonly encountered in a variety of clinical settings. Cardiac etiologies of dyspnea are an important consideration; among these, valvular heart disease (Variant 1), arrhythmia (Variant 2), and pericardial disease (Variant 3) are reviewed in this document. Imaging plays an important role in the clinical assessment of these suspected abnormalities, with usually appropriate procedures including resting transthoracic echocardiography in all three variants, radiography for Variants 1 and 3, MRI heart function and morphology in Variants 2 and 3, and CT heart function and morphology with intravenous contrast for Variant 3. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Performing chest computed tomography on pediatric patients on extracorporeal membrane oxygenation (ECMO): a stepwise approach.

Chest CT in pediatric patients on extracorporeal membrane oxygenation (ECMO) can be done safely and provide valuable high-quality diagnostic images to help guide patient management. An understanding of the basics of the ECMO circuit, cannula locations, where and how to inject contrast media, and how to time image acquisition is vital for the radiologist. Additionally, understanding the precautions associated with performing these exams is essential to ensure the safety of the child. This article provides a brief review of pediatric ECMO and its challenges and considerations, as well as a stepwise approach to perform and optimize these exams safely.

CT Fractional Flow Reserve: A Practical Guide to Application, Interpretation, and Problem Solving.

CT fractional flow reserve (FFRCT) is a physiologic simulation technique that models coronary flow from routine coronary CT angiography (CTA). To evaluate lesion-specific ischemia, FFRCT is measured 2 cm distal to a stenotic lesion. FFRCT greater than 0.8 is normal, 0.76-0.8 is borderline, and 0.75 or less is abnormal. FFRCT should always be interpreted in correlation with clinical and anatomic coronary CTA findings. FFRCT increases the specificity of coronary CTA in the evaluation of coronary artery disease, decreases the prevalence of nonobstructive disease in invasive coronary angiography (ICA), and helps with revascularization decisions and planning. Patients with intermediate-risk coronary anatomy at CTA and abnormal FFRCT can undergo ICA and revascularization, whereas those with normal FFRCT can be safely deferred from ICA. In borderline FFRCT values, management is decided in the context of the clinical scenario, but many cases could be safely managed with medical treatment. There are some limitations and pitfalls of FFRCT. Abnormal FFRCT values can be seen in mild stenosis, and normal FFRCTvalues can be seen in severe stenosis. Gradually decreasing or abnormal low FFRCT values at the distal vessel without a proximal focal lesion could be due to diffuse atherosclerosis. Coronary stents, bypass grafts, coronary anomalies, coronary dissection, transcatheter aortic valve replacement, unstable angina, and acute or recent myocardial infarction are situations in which FFRCT has not been validated and should not be used at this time. The authors provide a practical guide to the applications and interpretation of FFRCT, focusing on common pitfalls and challenges. Online supplemental material is available for this article. ©RSNA, 2022.

Imaging Features of Complications after Coronary Interventions and Surgical Procedures.

Coronary artery interventions and surgical procedures are used in the treatment of coronary artery disease and some congenital heart diseases. Cardiac and noncardiac complications can occur at variable times after these procedures, with the clinical presentation ranging from asymptomatic to devastating symptoms. Invasive coronary angiography is the reference standard modality used in the evaluation of coronary arteries, with intravascular US and optical coherence tomography providing high-resolution information regarding the vessel wall. CT is the mostly commonly used noninvasive imaging modality in the evaluation of coronary artery intervention complications and allows assessment of the stent, lumen of the stent, lumen of the coronary arteries, and extracoronary structures. MRI is limited to the evaluation of the proximal coronary arteries but allows comprehensive evaluation of the myocardium, including ischemia and infarction. The authors review the clinical symptoms and pathophysiologic and imaging features of various complications of coronary artery interventions and surgical procedures. Complications of percutaneous coronary interventions are discussed, including restenosis, thrombosis, dissection of coronary arteries or the aorta, coronary wall rupture or perforation, stent deployment failure, stent fracture, stent infection, stent migration or embolism, and reperfusion injury. Complications of several surgical procedures are reviewed, including coronary artery bypass grafting, coronary artery reimplantation procedure (for anomalous origin from opposite sinuses or the pulmonary artery or as part of surgical procedures such as arterial switching surgery and the Bentall and Cabrol procedures), coronary artery unroofing, and the Takeuchi procedure. Online supplemental material is available for this article. ©RSNA, 2021.

Ventriculotomy Decreases Agreement Between Assessment of Right Ventricular Function by Echocardiography and Cardiac Magnetic Resonance Imaging in Patients with Hypoplastic Left Heart Syndrome.

Accurate assessment of the right ventricular (RV) volume and function is important in patients with hypoplastic left heart syndrome (HLHS). We sought to investigate the effect of ventriculotomy on the correlation of RV functional assessments by two-dimensional echocardiography (2DE) to cardiac magnetic resonance (CMR)-derived RV ejection fraction (EF) in patients with HLHS. A retrospective re-analysis of CMR imaging with matched 2DE was performed from the institutional HLHS registry. Echocardiographic RV functional parameters were analyzed and correlated with CMR-derived EF. Intraclass correlation coefficient was used to determine interobserver reliability. A total of 58 matched echocardiograms and CMR imaging studies from 46 patients was evaluated. Median duration between CMR imaging and echocardiogram was 1 day (range 0-6 days). No significant difference was seen in CMR RV EF between patients with and without a ventriculotomy (EF - 43.6% vs 44.7%, p = 0.85). The presence of a ventriculotomy significantly decreased the correlation of biplane FAC (r = 0.86 vs 0.52; p = 0.02), triplane FAC (r = 0.84 vs 0.49; p = 0.03), and 2DE visually estimated EF (r = 0.83 vs 0.49; p = 0.02). The correlation of circumferential and longitudinal strains to CMR-derived EF was not significantly affected by the presence of a ventriculotomy. A prior ventriculotomy significantly affected correlation between 2DE FAC and visually estimated EF with CMR-derived EF. The dyskinetic myocardial segment due to ventriculotomy, which is often not visualized by 2DE, may be the reason for this discrepancy.

Negative Impact of the Left Ventricular Remnant Morphology on Systemic Right Ventricular Myocardial Deformation in Hypoplastic Left Heart Syndrome.

Left ventricular (LV) morphology may affect right ventricular (RV) function before and after Fontan palliation in patients with hypoplastic left heart syndrome (HLHS). We sought to assess the potential impact of LV morphology on RV function in patients with HLHS using cardiac magnetic resonance (CMR) imaging. A retrospective analysis of available CMR scans from all patients with HLHS was performed. LV morphology was categorized as absent/slit-like or globular/miniaturized. Volumetric analysis was performed using manual disc-summation method on steady-state free precession (SSFP) stack obtained in short-axis orientation of the ventricles. 4-chamber and short-axis SSFP images were used to measure strain on a semi-automated feature-tracking (FT) module. Two sample t-test was used to compare the groups. A total of 48 CMR scans were analyzed. Of those, 12 patients had absent/slit-like and 36 had globular/miniaturized LV morphology. Averaged 4-chamber longitudinal RV strain was significantly higher for absent/slit-like (- 17.6 ± 4.7%) than globular/miniaturized (- 13.4 ± 3.5; P = 0.002). Averaged 4-chamber radial RV strain was also significantly higher for absent/slit-like (33.1 ± 14.9%) than globular/miniaturized (21.6 ± 7.1; P = 0.001). For globular/miniaturized LV morphology, the decreases of 4-chamber longitudinal and radial strains were mainly attributable to the septal basilar and septal mid-ventricular segments. No differences were found in short-axis RV global circumferential strain between the morphologic subtypes (absent/slit-like - 15.0 ± 6.5, globular/miniaturized - 15.7 ± 4.7; P = 0.68). Larger LV remnants, with globular/miniaturized LV morphology, demonstrated diminished strain in the septal base and mid-ventricle segments. Patients with globular/miniaturized LV morphology may benefit with closer monitoring and lower threshold to start heart failure medications. These results exemplify the utility of including both septal and regional deformation in systemic RV strain analysis.

Statement from the North American Society for Cardiovascular Imaging on imaging strategies to reduce the scarcity of healthcare resources during the COVID-19 outbreak.

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is an evolving global pandemic that is predicted to strain healthcare resources at multiple locations throughout North America and the World. As of April 6, 2020, the apex of infection rates is predicted to occur within 1 to 5 weeks at various locations. Widespread reports of personal protective equipment (PPE) shortages, and healthcare worker exposure to disease have become commonplace. To mitigate this crisis, we are suggesting imaging strategies that aim to use the least PPE, require the smallest number of potential staff exposures, and streamlines utilization of imaging. They are broadly organized by (1) substituting a noninvasive diagnostic test in place of a semi-invasive or invasive diagnostic tests, and (2) consolidating diagnostic imaging.

ACR Appropriateness Criteria® Chest Pain-Possible Acute Coronary Syndrome.

Chest pain is a frequent cause for emergency department visits and inpatient evaluation, with particular concern for acute coronary syndrome as an etiology, since cardiovascular disease is the leading cause of death in the United States. Although history-based, electrocardiographic, and laboratory evaluations have shown promise in identifying coronary artery disease, early accurate diagnosis is paramount and there is an important role for imaging examinations to determine the presence and extent of anatomic coronary abnormality and ischemic physiology, to guide management with regard to optimal medical therapy or revascularization, and ultimately to thereby improve patient outcomes. A summary of the various methods for initial imaging evaluation of suspected acute coronary syndrome is outlined in this document. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Electrocardiogram-Gated Computed Tomography with Coronary Angiography for Cardiac Substructure Delineation and Sparing in Patients with Mediastinal Lymphomas Treated with Radiation Therapy.

PURPOSE: (1) Demonstrate feasibility of electrocardiogram-gated computed tomography with coronary angiography (E-CTA) in treatment planning for mediastinal lymphoma and (2) assess whether inclusion of cardiac substructures in the radiation plan optimization (CSS optimization) results in increased cardiac substructure sparing. METHODS AND MATERIALS: Patients with mediastinal lymphomas requiring radiation therapy were prospectively enrolled in an observational study. Patients completed a treatment planning computed tomography scan and E-CTA in the deep inspiration breath hold position. Avoidance structures (eg, coronary arteries and cardiac valves) were created in systole and diastole and then merged into a single planning organ-at-risk volume based on a cardiac substructure contouring atlas. In the photon cohort, 2 volumetric modulated arc therapy plans were created per patient with and without CSS optimization. Dosimetric endpoints were compared. RESULTS: In the photon cohort, 7 patients were enrolled. For all 7 patients, the treating physician elected to use the CSS optimization plan. At the individual level, 2 patients had reductions of 10.8% and 16.2% of the right coronary artery receiving at least 15 Gy, and 1 had a reduction of 9.6% of the left anterior descending artery receiving 30 Gy. No other differences for coronary arteries were detected between 15 and 30 Gy. Conversely, 5 of 7 patients had >10% reductions in dose between 15 to 30 Gy to at least 1 cardiac valve. The greatest reduction was 22.8% of the aortic valve receiving at least 30 Gy for 1 patient. At the cohort level, the maximum, mean, and 5-Gy increment analyses were nominally similar between planning techniques for all cardiac substructures and the lungs. CONCLUSIONS: Cardiac substructure delineation using E-CTA was feasible, and inclusion in optimization led to modest improvements in sparing of radiosensitive cardiac substructures for some patients.

Guiding peripheral arterial disease management with magnetic resonance imaging.

Peripheral arterial disease (PAD) management is exceptionally challenging. Despite advances in diagnostic and therapeutic technologies, long-term vessel patency and limb salvage rates are limited. Patients with PAD frequently require extensive workup with noninvasive tests and imaging to delineate their disease and help guide appropriate management. Ultrasound and computed tomography are commonly ordered in the workup of PAD. Magnetic resonance imaging (MRI), on the other hand, is less often acknowledged as a useful tool in this disease. Nevertheless, MRI is an important test that can effectively characterize atherosclerotic plaque, assess vessel patency in highly calcified disease, and measure lower extremity perfusion.

Computed Tomography Imaging of Cardiac Masses.

Although not considered a first-line modality for assessing cardiac masses, computed tomography (CT) can provide clinically useful information and is underused for this purpose. In addition to characterizing masses with insights about presence of fat or calcification and the perfusion characteristics of a mass, CT produces high-resolution four-dimensional images depicting the mass and its relationship to chambers, valves, and coronaries. This is combined with imaging of the chest, abdomen, or coronaries. Advances in CT technology, such as dual-energy CT, dynamic perfusion imaging, and three-dimensional printing for preoperative planning, will increase the role of CT in assessment of cardiac masses.

Usefulness of Cardiac Magnetic Resonance Imaging in Patients With Acute Spontaneous Coronary Artery Dissection.

Cardiac magnetic resonance (CMR) has significant diagnostic and prognostic utility in myocardial infarction evaluation. However, its application in spontaneous coronary artery dissection (SCAD) is not described. Patients with confirmed SCAD who had CMR performed within 8 days of the index SCAD were reviewed. Clinical variables including demographics and medical history were recorded. CMR indexes, including myocardial delayed enhancement (MDE), microvascular obstruction, perfusion defects, left ventricular ejection fraction, and wall motion score index were measured. A total of 18 patients (all women, mean age 47.1 years) were included. Overall burden of atherosclerotic risk factors was low; 3 had a previous SCAD. Two patients underwent CMR before coronary angiography, whereas the others received CMR thereafter. Mean time between SCAD diagnosis and CMR completion was 2.7 days (range 0 to 8). Mean left ventricular ejection fraction and wall motion score index were 56.1% and 1.27, respectively. A total of 15 patients had MDE consistent with myocardial infarction in the SCAD distribution(s) identified on coronary angiography, with 8 patients having concomitant microvascular obstruction. Ten patients had transmural MDE. At follow-up (mean 386 days), all patients were alive; extracoronary vascular abnormalities were identified in 14; 6 had recurrent chest pain; and 2 had recurrent SCAD. Both patients with recurrent SCAD had no unique features on CMR to predict a future event. In conclusion, CMR provided significant value in clarifying the diagnosis and assessing for adverse sequelae after acute SCAD. Further studies are needed to determine its role in SCAD prognostication.

Time-resolved contrast-enhanced MR angiography with single-echo Dixon fat suppression.

PURPOSE: Dixon-based fat suppression has recently gained interest for dynamic contrast-enhanced MRI, but multi-echo techniques require longer scan times and reduce temporal resolution compared to single-echo alternatives without fat suppression. The purpose of this work is to demonstrate accelerated single-echo Dixon imaging with high spatial and temporal resolution. THEORY AND METHODS: Real-valued water and fat images can be obtained from a single measurement if the shared initial phase and that due to ΔB0 are assumed known a priori. An expression for simultaneous sensitivity encoding (SENSE) unfolding and fat-water separation is derived for the general undersampling case, and simplified under the special case of uniform Cartesian undersampling. In vivo experiments were performed in extremities and brain with SENSE acceleration factors of up to R = 8. RESULTS: Single-echo Dixon reconstruction of highly undersampled data was successfully demonstrated. Dynamic contrast-enhanced water and fat images provided high spatial and temporal resolution dynamic images with image update times shorter than previous single-echo Dixon work. CONCLUSION: Time-resolved contrast-enhanced MRI with single-echo Dixon fat suppression shows high image quality, improved vessel delineation, and reduced sensitivity to motion when compared to time-subtraction methods.

Cardiac MR elastography using reduced-FOV, single-shot, spin-echo EPI.

PURPOSE: To implement a reduced field of view (rFOV) technique for cardiac MR elastography (MRE) and to demonstrate the improvement in image quality of both magnitude images and post-processed MRE stiffness maps compared to the conventional full field of view (full-FOV) acquisition. METHODS: With Institutional Review Board approval, 17 healthy volunteers underwent both full-FOV and rFOV cardiac MRE scans using 140-Hz vibrations. Two cardiac radiologists blindly compared the magnitude images and stiffness maps and graded the images based on several image quality attributes using a 5-point ordinal scale. Fisher's combined probability test was performed to assess the overall evaluation. The octahedral shear strain-based signal-to-noise ratio (OSS-SNR) and median stiffness over the left ventricular myocardium were also compared. RESULTS: One volunteer was excluded because of an inconsistent imaging resolution during the exam. In the remaining 16 volunteers (9 males, 7 females), the rFOV scans outperformed the full-FOV scans in terms of subjective image quality and ghosting artifacts in the magnitude images and stiffness maps, as well as the overall preference. The quantitative measurements showed that rFOV had significantly higher OSS-SNR (median: 1.4 [95% confidence interval (CI): 1.2-1.5] vs. 2.1 [95% CI: 1.8-2.4]), P < 0.05) compared to full-FOV. Although no significant change was found in the median myocardial stiffness between the 2 scans, we observed a decrease in the stiffness variation within the myocardium from 2.1 kPa (95% CI: [1.9, 2.3]) to 1.9 kPa (95% CI: [1.7, 2.0]) for full-FOV and rFOV, respectively (P < 0.05) in a subgroup of 7 subjects with ghosting present in the myocardium. CONCLUSION: This pilot volunteer study demonstrated that rFOV cardiac MRE has the capability to reduce ghosting and to improve image quality in both MRE magnitude images and stiffness maps. Magn Reson Med 80:231-238, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

Spontaneous coronary artery dissection: challenges of coronary computed tomography angiography.

BACKGROUND: There is limited understanding of the role of cardiac computed tomography angiography (CCTA) for assessment of patients with spontaneous coronary artery dissection (SCAD). METHODS: In this report we describe the diagnostic utility of CCTA in three young women presenting with signs and symptoms of myocardial ischemia who were eventually diagnosed with SCAD. RESULTS: None of the women had traditional atherosclerotic risk factors. SCAD was not initially identified on CCTA in any of the three women, but was visualized during retrospective analysis in two patients after invasive coronary angiography. In two patients follow-up CCTA imaging was used successfully for subsequent management. CONCLUSIONS: In patients presenting with signs or symptoms of acute coronary syndrome, SCAD may be missed or not detectable on CCTA. A negative CCTA should not exclude a diagnosis of SCAD, and invasive coronary angiography should be considered for further evaluation.