Low-dose CT lung cancer screening reduces lung cancer mortality in individuals at high risk and frequently reveals clinically relevant incidental findings. In the National Lung Screening Trial, approximately one-third of screening CT examinations demonstrated abnormalities other than lung cancer, raising challenges related to interpretation, reporting, and further management. The absence of consistent guidance and the variable clinical significance of these findings may hinder the broader adoption of lung cancer screening. Opportunistic screening leverages low-dose CT examinations performed for lung cancer detection to identify additional serious conditions at no extra cost, radiation exposure, or patient burden. The authors provide a practical framework for recognizing, reporting, and managing common opportunistic findings on lung cancer screening CT images, with an emphasis on evidence-based recommendations and current professional society guidance. Key thoracic findings include emphysema, interstitial lung abnormalities, interstitial lung disease, coronary artery calcification, thoracic aortic aneurysm, and pulmonary artery enlargement. Each of these findings, if unrecognized, is associated with substantial morbidity and mortality. Extrapulmonary findings such as low bone density and lesions found incidentally in the upper abdominal organs further expand the clinical value of lung cancer screening. The authors highlight standardized visual and quantitative assessment methods, recommended follow-up pathways, and the importance of structured reporting, including appropriate use of the Lung CT Screening Reporting and Data System "S" (other non-lung cancer findings) modifier. Emerging artificial intelligence tools are discussed as critical enablers for scalable opportunistic screening, offering automated detection, quantification, and longitudinal assessment of emphysema, coronary calcium levels, vascular dimensions, bone density, body composition, and selected abdominal pathologic conditions. By integrating opportunistic screening into routine lung cancer screening workflows, radiologists can extend the benefit of lung cancer screening with CT beyond cancer detection to facilitate comprehensive risk stratification and preventive care.
Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related mortality worldwide and most often arises in patients with chronic liver disease and cirrhosis. Since curative treatment options are largely limited to early-stage disease, effective surveillance strategies are essential to improve outcomes. Current guidelines recommend semiannual US combined with serum α-fetoprotein level testing as the standard surveillance approach for most patients at high risk. Liver Imaging Reporting and Data System 2024 guidance provides a structured framework for interpretation of surveillance US and highlights the importance of examination quality assessment and reporting by incorporating it into the management decision-making algorithm. US surveillance improves early tumor detection and survival but demonstrates suboptimal sensitivity in certain high-risk subgroups, particularly patients with obesity, hepatic steatosis, and advanced cirrhosis. Growing evidence supports the use of alternative strategies including biomarker panel results and abbreviated MRI protocols in selected patient subgroups because these approaches demonstrate higher sensitivity and favorable cost-effectiveness when applied to appropriately risk-stratified populations. Furthermore, cost-effectiveness analyses consistently indicate that surveillance efficiency strongly depends on individual HCC risk, imaging costs, surveillance use, and societal willingness-to-pay thresholds, supporting a departure from uniform "one-size-fits-all" strategies in favor of personalized, risk-adapted surveillance paradigms. Despite advances in diagnostic performance, surveillance use remains suboptimal in clinical practice due to patient-, provider-, and system-level barriers. The authors aim to synthesize current evidence on HCC surveillance including identifying target populations; evaluating the diagnostic performance of available modalities; and considering cost-effectiveness, emerging technologies, and real-world barriers to implementation of surveillance protocols.
Although infection accounts for the majority of acute diffuse airspace disease in dyspneic patients with hematologic malignancy, radiologists must also recognize a spectrum of noninfectious pulmonary conditions that can mimic infection. These less common entities are often unfamiliar and diagnostically challenging for radiologists but are also complex diagnoses for clinicians to establish without expert radiologic assistance. The misdiagnosis of infection and associated delays in correct diagnosis in these patients can significantly increase morbidity and mortality. The authors highlight noninfectious causes of dyspnea and associated diffuse parenchymal disease that often manifest with clinical characteristics mimicking infection. These include drug toxicities and treatment-related complications (particularly to new therapies and treatment regimens), associated edema and hemorrhage, complications of primary disease, and associated secondary disorders. Although imaging findings often overlap with those of infection, radiologists aware of these conditions can aid in accurate diagnosis by integrating knowledge of predisposing clinical scenarios, recognizing distinguishing imaging features and their temporal evolution, and correlating with clinical parameters. Although confirmation of these alternate noninfectious conditions is not always possible by imaging alone, radiologic interpretation may prompt additional specific tests that can corroborate the correct diagnosis. Timely accurate diagnoses of noninfectious causes can improve diagnostic accuracy and patient outcomes in this vulnerable population.
Segmentation and processing of CT datasets for transcatheter aortic valve replacement (TAVR) planning is now an essential part of the transcatheter heart valve team process. Output for TAVR planning includes geometric and pathologic findings of the aortic valve, root, and left ventricular outflow tract. In addition, access route selection requires assessment of the size and course of the access vessel and identification of any associated variant anatomic or pathologic conditions that could affect the procedure. Spurious or erroneous output from three-dimensional processing software can occur, especially with gradient-based segmentation algorithms. Identification and correction of these processing errors is imperative for accurate TAVR planning output. The authors review specific considerations for each anatomic region in which TAVR planning is needed and outline processing tips for providing high-quality planning output. ©RSNA, 2026 Supplemental material is available for this article.
This slideshow presentation provides a practical image-based road map to essential spinal and pelvic radiographic measurements, with stepwise instructions and reference values, for assessment and management of spinal disorders.
The presacral space is a complex anatomic region that harbors a heterogeneous group of masses arising from diverse embryologic remnants. These lesions are uncommon and often detected incidentally. Surgical resection remains the mainstay of treatment, as approximately 60% of solid and 10% of cystic lesions are malignant. Cystic lesions, particularly developmental cysts, may also become infected or undergo malignant transformation. In selected cases of benign-appearing, small, asymptomatic cystic lesions, periodic imaging surveillance may be considered, with surgery reserved for those that develop worrisome changes at follow-up. MRI is the modality of choice for lesion characterization and preoperative planning. Distinguishing benign from malignant lesions depends on internal composition, morphology, and enhancement pattern. In cystic lesions, the presence of solid enhancing components represents the most reliable indicator of malignancy. The authors describe the role of different imaging techniques in the evaluation of these lesions and highlight key radiologic features as part of an image-based algorithm for lesion characterization, with emphasis on radiologic-pathologic correlation. This framework can help radiologists narrow the differential diagnosis and, in selected cases, establish a definitive diagnosis. Information that should be included in the MRI report and the current role of preoperative biopsy in the management of these lesions are also discussed. ©RSNA, 2026 Supplemental material is available for this article.
Breast biopsy markers have evolved from simple metallic markers to sophisticated multimaterial devices that serve critical purposes throughout the breast cancer care continuum. This evolution began at The University of Texas MD Anderson Cancer Center in the 1960s for gynecologic and head and neck tumors. After the MicroMark (Biopsys) clip was approved by the U.S. Food and Drug Administration in 1995, markers were subsequently adapted for patients with breast cancer in 1999. By 2003, markers had become the standard of care. Modern markers serve multiple clinical functions: marking biopsy sites, facilitating cross-modality imaging correlation, guiding surgical planning and radiation therapy targeting, and ensuring continuity of care across health care facilities. Long-term studies demonstrate excellent safety profiles with minimal adverse events and significant cost-effectiveness through improved surgical precision and reduced re-excision rates. Despite the widespread adoption of these markers, contemporary challenges persist, including marker migration, allergic reactions to metallic components or embedding materials, and visibility limitations on US images. However, recent technological advances address these concerns through improved marker designs, nonmetallic alternatives, and innovative detection methods. Current best practices emphasize optimal placement timing, appropriate marker selection based on patient-specific factors, migration prevention techniques, and use of Doppler US "twinkling" artifacts for enhanced US visualization. © The Author(s) 2026. Published by the Radiological Society of North America under a CC BY 4.0 license. Supplemental material is available for this article.
Lacunar strokes are small subcortical infarcts that result from the occlusion of small perforating arteries, and they comprise about 25% of all strokes. Unlike other types of infarcts, lacunar strokes are primarily due to cerebral small vessel disease. Detection of acute lacunar infarcts may be challenging due to their small size, but it can be improved with clinical-radiologic correlation. Numerous mimics should also be kept in mind in the differential diagnosis. While lacunar infarcts are more often asymptomatic, they may manifest with distinct clinical syndromes. Five classic lacunar syndromes are commonly recognized: pure motor hemiparesis, pure sensory stroke, sensorimotor stroke, ataxic hemiparesis, and dysarthria-clumsy hand syndrome. Beyond these, numerous atypical lacunar syndromes such as internuclear ophthalmoplegia, isolated dysarthria, hemichorea and hemiballismus, and paramedian thalamic syndrome have been described. Each of these has a unique clinical manifestation linked to lesions in specific neuroanatomic pathways. The authors provide a comprehensive overview of lacunar strokes, emphasizing their diverse clinical manifestations and the crucial role of imaging in diagnosis of these infarcts. ©RSNA, 2026 Supplemental material is available for this article.
Pediatric supratentorial tumors are almost always primary brain tumors. They are defined by a relatively short list of diagnoses that can be broadly divided into tumors with high-grade and low-grade features, intraventricular lesions, and other rare tumors. The differential diagnosis can be further narrowed depending on age at presentation and particular imaging features. Treatment in most cases is surgical resection and may be followed by adjuvant therapy. Many tumors, such as high-grade glioma, ependymoma, and atypical teratoid rhabdoid tumor, are associated with specific genetic mutations that determine diagnosis and prognosis. ©RSNA, 2026 Supplemental material is available for this article.
Adnexal lesions seen on US images are referred for MRI when there is a need for further characterization and more accurate cancer risk score assessment. MRI can help expedite referral to gynecologic oncologists when ovarian cancers are suspected and avoid unnecessary, overextensive surgery or unnecessary follow-up when benign lesions are identified. The Ovarian-Adnexal Reporting and Data System (O-RADS) MRI was developed to provide standardized lexicon terminology and to allow predicting the risk of cancer when the appropriate MRI protocol is used. Only when the MRI protocol with the minimum technical requirements and dynamic contrast-enhanced imaging is used can the positive predictive values listed in the O-RADS MRI table be obtained. The O-RADS MRI recommended protocol includes multiplanar T2-weighted imaging, diffusion-weighted imaging, in- and opposed-phase imaging, and pre- and postcontrast imaging, including dynamic contrast-enhanced imaging. Optimizing each MRI sequence may be challenging but will lead to accurate risk stratification of adnexal lesions. It is also important to understand how each sequence is used to assess adnexal lesion characteristics for accurate risk scoring. This article reviews the necessary sequences in the recommended O-RADS MRI protocol and offers tips and tricks that can be used to optimize images, negate common artifacts, and avoid common errors in interpretation, including when the MRI examination is suboptimal. ©RSNA, 2026 See the invited commentary by Lakhman and Rakow-Penner in this issue.
Virtual surgical planning (VSP) and clinical 3D printing (C3DP) enable patient-specific anatomic models and surgical guides to be developed and produced from medical imaging using additive manufacturing techniques in a health care facility. This affords a level of precision beyond that allowed with conventional techniques, shortens surgical times, decreases rates of surgical complications and blood loss, and improves patient outcomes. The authors outline the general principles of VSP-C3DP used by subject matter experts in the clinical, imaging, engineering, and manufacturing domains, including image acquisition (eg, thin-section imaging, dual-energy CT, pediatric imaging, MRI bone imaging, interpolation, multimodal imaging); image segmentation (eg, manual and automated); virtual modeling and surgical guide design (eg, segmentation to model conversion, design principles); printing, processing, and delivery of models (eg, material selection); quality assurance (eg, risk assessment and mitigation, validation, troubleshooting, and rescue strategies); and knowledge of the current regulatory and reimbursement landscape. The authors describe how VSP-C3DP is used through case samples in specific orthopedic, hand, and spine surgical procedures to simulate, rehearse, and execute the preoperative plan in the broad categories of arthroplasty (ie, shoulder arthroplasty), joint realignment (eg, periacetabular osteotomy and distal femoral and high tibial osteotomy), deformity correction (eg, high cervical fusion, correction of lumbar spondylolisthesis, distal radius deformities, distal ulna malunions, alunions, pediatric metatarsal deformities, pelvic fracture fixation, treatment of Blount disease), and tumor excision (eg, humerus osteochondroma, pelvic iliac wing osteosarcoma, and giant cell tumors of the distal femur). Current limitations and potential future directions of VSP-C3DP are discussed. ©RSNA, 2026 Supplemental material is available for this article.
Vascular abnormalities in athletes, although less common than musculoskeletal injuries, present a significant diagnostic challenge due to overlapping manifestations. These conditions range from subtle exertional discomfort to potentially limb-threatening ischemia and life-threatening complications such as pulmonary embolism or sudden cardiac death. In this comprehensive review, the authors highlight the spectrum of vascular abnormalities encountered in athletes, emphasizing the pivotal role of multimodality imaging, including US, CT angiography, MR angiography, and conventional angiography in their accurate diagnosis and effective management. They discuss upper extremity conditions such as Paget-Schroetter syndrome, quadrilateral space syndrome, palmar arch injury, and digital ischemia. Lower extremity conditions discussed include arterial thromboembolism, external iliac artery endofibrosis and dissection, adductor canal syndrome, chronic exertional compartment syndrome, popliteal entrapment syndromes, venous insufficiency, and cystic adventitial disease. Other conditions discussed include venous thromboembolism, median arcuate ligament compression, aortopathies, pulmonary hypertension, Bezold-Jarisch reflex, coronary artery disease, coronary anomalies, and high-flow priapism. The authors aim to equip radiologists with essential knowledge to promptly recognize these conditions, thereby facilitating early intervention and improved outcomes. ©RSNA, 2026 Supplemental material is available for this article. See the invited commentary by Nagpal and Bluemke in this issue.
