Radiographics最新文献

Cerebrospinal fluid (CSF) is an essential component of the central nervous system, and disruption of normal CSF flow from the lateral ventricles to the subarachnoid spaces around the brain and spinal canal can have serious consequences. Nuclear imaging may be useful to help diagnose abnormalities in CSF flow; cisternograms can be used to assess for CSF leaks or normal-pressure hydrocephalus, and shuntograms can be used to evaluate for CSF shunt malfunction. The authors review normal and pathologic findings and pitfalls of cisternography and shuntogram examinations. ^©RSNA, 2025.

Sports cardiologists specialize in the care of competitive athletes and highly active people by detecting and managing cardiovascular diseases that can impact sports participation and counseling on return to sports after cardiovascular events. Preparticipation evaluation of athletes includes history, physical examination, and electrocardiography (ECG), with exercise ECG added when screening master athletes. If the findings are abnormal or inconclusive, echocardiography is used for further evaluation. Further imaging with MRI, CT, or stress test is performed for establishing a diagnosis when echocardiography is indeterminate or discordant with clinical features and for risk stratification if echocardiography provides a definitive diagnosis. MRI can help distinguish athlete's heart from similar-appearing pathologic entities when echocardiography is inconclusive. Athlete's heart can manifest as left ventricular hypertrophy (LVH), left ventricle (LV) dilatation, prominent LV trabeculations, and right ventricular (RV) dilatation. Adaptive LVH in athletes is concentric and typically measures less than 16 mm, which distinguishes it from pathologic LV thickening of hypertrophic cardiomyopathy, hypertension, valvular disease, and infiltrative cardiomyopathies. Adaptive LV dilatation with normal or mildly reduced ejection fraction can be seen in endurance athletes. LV ejection fraction greater than 40%, augmentation of LV ejection fraction with exercise, and normal or supranormal diastolic function distinguishes it from dilated cardiomyopathy. Physiologic RV dilatation in athletes is distinguished from arrhythmogenic cardiomyopathy (RV type) by global involvement and absence of major regional wall motion abnormalities or late gadolinium enhancement. MRI is also useful in diagnosis and risk stratification of athletes with cardiovascular symptoms and after major cardiovascular events such as arrhythmias, myocardial infarction, and resuscitated sudden cardiac death or arrest. CT angiography provides accurate evaluation of coronary artery anomalies and coronary artery disease. ^©RSNA, 2025 Supplemental material is available for this article.

Lung volume reduction is a treatment option for patients with severe emphysema and predominant chronic obstructive pulmonary disease that is refractory to medical treatment. These patients often experience symptoms associated with hyperinflation including dyspnea and exercise limitation. In recent years, bronchoscopic lung volume reduction using endobronchial valve (EBV) therapy has emerged as a U.S. Food and Drug Administration-approved and less invasive alternative to lung volume reduction surgery. The two approved one-way valves allow air to exit the lung but prohibit air from entering, with the intended goal of reducing hyperinflation. After patients meet clinical eligibility criteria, imaging has an integral role in preprocedural and postprocedural assessment. Findings from qualitative and quantitative preprocedural thin-section CT and perfusion scintigraphic analysis provides the characterization of emphysema, degree of collateral ventilation, and lung perfusion data necessary for target lobe selection, while aiding in detection of the presence of contraindications to the procedure, including suspicious pulmonary nodules, significant bronchiectasis, large bullae, and pleural adhesions. At procedure completion, chest radiography is required for assessment of complications, most commonly pneumothorax. Subsequent imaging may determine whether the procedure has successfully induced lobar atelectasis as well as the presence of additional complications such as infection and valve malposition or migration. Knowledge of EBV therapy and pertinent imaging findings is crucial in optimizing patient selection for the procedure, identifying complications, and evaluating treatment response. ^©RSNA, 2025.

Formerly termed sports hernia or athletic pubalgia, core muscle injury (CMI) encompasses abnormality of structures within the so-called core, which is essentially the hip, abdomen, and pubis. Compared with data on image-guided procedures of other joints, information regarding procedures performed to address CMI and other disorders of the pubic symphysis is lacking. These procedures can be daunting given the joint's small size, surrounding critical neurovascular structures, and three-dimensional anatomy. Nonetheless, various diagnostic and therapeutic image-guided interventions in this region can be successfully performed by the astute radiologist. Diagnostic symphyseography provides a contrast agent map that allows detection of symphyseal cleft injuries. Although largely supplanted with MRI, which can help depict additional findings such as bone marrow edema and atypical cleft injuries, symphyseography performed alongside local anesthetic and steroid injection remains a valuable conservative therapeutic strategy in the treatment of CMI. US-guided percutaneous dry needling (tenotomy) is thought to promote tendon healing by using repeated needle passage to convert chronic degeneration of tendinosis into an acute inflammatory condition; the distal rectus abdominis and/or proximal adductor longus may be targeted. Other perisymphyseal procedures include joint aspiration, biopsy, and osteoplasty. Fluoroscopic- or US-guided joint aspiration aids in evaluation of arthropathies. While bone and soft-tissue biopsies are best performed under CT guidance, fluoroscopy and US are viable alternatives in the evaluation of lesions with significant extraosseous components. Percutaneous osteoplasty is a minimally invasive palliative procedure that stabilizes pubic metastases by injecting bone cement; it can be performed under fluoroscopic or CT guidance by itself or with thermal ablation to maximize pain relief. ^©RSNA, 2025 Supplemental material is available for this article.

Hepatobiliary (HB) contrast agents are increasingly valuable diagnostic tools in MRI, offering a wider range of applications as their clinical use expands. Normal hepatocytes take up HB contrast agents, which are subsequently excreted in bile. This property creates a distinct HB phase providing valuable insights into liver function and biliary anatomy. HB contrast agents can assist in diagnosing a broad spectrum of HB diseases ranging from diffuse liver disease to focal hepatic lesions and can delineate anatomic details of the biliary tree. Understanding the pharmacodynamics of HB contrast agents is paramount to their appropriate clinical application and troubleshooting. HB phase hypointensity can arise from various diffuse and focal abnormalities that may or may not be associated with biliary excretion. Hypointensity during the HB phase can be broadly grouped into diffuse hypointensity, regional hypointensity, and focal lesions for better evaluation of the underlying cause. Abnormalities may arise from hepatic parenchymal, biliary, or vascular causes, or a combination thereof in each of the broad groups. Recognition of a suboptimal hypointense HB phase is important in the evaluation of focal lesions in patients with cirrhosis of the liver and particularly in those with hepatocellular carcinoma. Furthermore, hypointensity can also suggest the aggressiveness of malignancies such as hepatocellular carcinoma or colorectal metastases, which may affect the prognosis. It is essential to consider all imaging findings relative to the clinical context and the complete set of the MRI sequences performed for diagnosis of liver abnormalities. This comprehensive approach minimizes the risk of misinterpretation or pitfalls. The authors aim to equip radiologists with key insights for accurately understanding hypointensity in the HB phase, ultimately leading to more accurate diagnoses. ^©RSNA, 2025 Supplemental material is available for this article.

Orthotopic heart transplant (OHT) is a well-established therapy for end-stage heart failure that leads to improved long-term survival rates, with careful allograft surveillance essential for optimizing clinical outcomes after OHT. Unfortunately, complications can arise after OHT that can compromise the success of the OHT. Cardiac MRI is continually evolving, with a range of advanced techniques that can be applied to evaluate allograft structure and function. Understanding the unique features of cardiac MRI in OHT recipients, identifying findings suggestive of acute or chronic complications, and recognizing the limitations of this imaging modality are essential for accurate interpretation of cardiac MRI findings and subsequent clinical reporting. The authors address the anticipated postsurgical anatomy and functionality of the OHT. Emphasis is placed on the advanced functional and tissue characterization features that can be seen in the stable OHT recipient, including global longitudinal strain, late gadolinium enhancement, native T1 and T2 mapping, and extracellular volume fraction. Subsequently, the evidence for detection of acute cardiac allograft rejection with cardiac MRI comprehensive tissue characterization techniques and the role of quantitative myocardial perfusion for cardiac allograft vasculopathy screening are discussed, with reference to their comparative standard of reference screening tests, including endomyocardial biopsy, invasive coronary angiography, and myocardial rest and stress perfusion PET/CT. Cardiac MRI has been included in contemporary OHT management guidelines and therefore can be considered a complementary tool for allograft evaluation. The authors demonstrate the complementary role cardiac MRI can play in cardiac allograft surveillance, with clinical examples. ^©RSNA, 2025 Supplemental material is available for this article. See the invited commentary by Agarwal in this issue.