Radiographics最新文献

Endometriosis is a chronic systemic condition characterized by the presence of ectopic endometrial-like tissue outside of the uterus. It occurs most often in reproductive-aged patients and less frequently in postmenopausal women. In postmenopausal patients, endometriosis is more common in those undergoing hormone replacement therapy or taking tamoxifen. The risk of malignant transformation of endometriosis is higher in this older population, especially in those undergoing estrogen-only hormone replacement therapy. Many theories on the postmenopausal pathogenesis of endometriosis have been proposed, ranging from reactivation of premenopausal disease to de novo manifestation. Compared with premenopausal disease, postmenopausal endometriosis is typically less active and extensive, with fewer hemorrhagic components. Patients may be symptomatic, with chronic pelvic pain, or may receive the diagnosis after imaging performed for other indications such as an incidental ovarian lesion. Treatment is typically surgical resection or estrogen-blocking medications. Although the diagnosis requires pathologic confirmation, radiologists play an important role in diagnosing both benign endometriosis and malignant transformation. Pelvic US following a dedicated protocol is an accessible screening tool, with high sensitivity for diagnosis of bowel-invasive disease. MRI has better anatomic resolution and allows simultaneous characterization of adnexal and extrapelvic lesions, thereby providing excellent assessment for malignant transformation.

The implementation of deep neural networks has spurred the creation of deep learning reconstruction (DLR) CT algorithms. DLR CT techniques encompass a spectrum of deep learning-based methodologies that operate during the different steps of the image creation, prior to or after the traditional image formation process (eg, filtered backprojection [FBP] or iterative reconstruction [IR]), or alternatively by fully replacing FBP or IR techniques. DLR algorithms effectively facilitate the reduction of image noise associated with low photon counts from reduced radiation dose protocols. DLR methods have emerged as an effective solution to ameliorate limitations observed with prior CT image reconstruction algorithms, including FBP and IR algorithms, which are not able to preserve image texture and diagnostic performance at low radiation dose levels. An additional advantage of DLR algorithms is their high reconstruction speed, hence targeting the ideal triad of features for a CT image reconstruction (ie, the ability to consistently provide diagnostic-quality images and achieve radiation dose imaging levels as low as reasonably possible, with high reconstruction speed). An accumulated body of evidence supports the clinical use of DLR algorithms in abdominal imaging across multiple CT imaging tasks. The authors explore the technical aspects of DLR CT algorithms and examine various approaches to image synthesis in DLR creation. The clinical applications of DLR algorithms are highlighted across various abdominal CT imaging domains, with emphasis on the supporting evidence for diverse clinical tasks. An overview of the current limitations of and outlook for DLR algorithms for CT is provided. ^©RSNA, 2024.

Childhood interstitial lung disease (chILD) encompasses a diverse group of genetic, infectious, and inflammatory conditions affecting infants and children. The recognition and understanding of these entities have highlighted the necessity for more accurate classification. This group of rare heterogeneous diseases comprises more than 200 different conditions and has a combined estimated prevalence of less than one patient per 100 000 children. Hence, a systematic diagnostic approach is crucial. This article describes a diagnostic approach for pediatric diffuse lung diseases in infancy, including an analysis of clinical presentations and imaging and histologic features to effectively distinguish among various chILD entities. Although they often have overlapping and nonspecific radiologic features, some chILD entities may exhibit typical imaging findings, resulting in a CT diagnosis or aiding in narrowing the differential diagnosis, thus guiding the clinician to the appropriate genetic tests, potentially limiting unnecessary biopsies. This approach aims to enhance the understanding and diagnosis of chILD in infants, thereby facilitating improved patient care.

Hidradenitis suppurativa, also referred to as inverse acne, manifests as a persistent inflammatory skin disorder characterized by lesions such as deep nodules, abscesses, sinus tracts, and fibrotic scars. These manifestations predominantly occur in skin folds and intertriginous areas, notably in the axillary, inguinal, perianal, perineal, and inframammary regions. Due to similarities with other conditions in its initial stages, accurate diagnosis of hidradenitis suppurativa is often delayed, sometimes spanning several years. Diagnosis relies on identifying specific morphologic features (such as deep, inflamed, and painful nodules; sinus tracts; and scars), considering the affected sites (skin folds and areas with apocrine glands), and recognizing the chronic nature of the condition (persistent course with periods of exacerbation and remission). There are no definitive biologic or pathologic diagnostic tests, and biopsy of the affected area is not necessary. Treatment varies based on severity and may include topical and systemic antibiotics, hormonal therapy, immunomodulators, and surgery. Due to associated pain, increased site sensitivity, secretion drainage, odor, and scarring, this condition can have a negative psychosocial impact. Imaging studies, including high-frequency US and MRI with subsequent three-dimensional reconstruction, serve as valuable tools for precise staging, monitoring disease activity, and preoperative assessment. Currently, high-frequency US stands as the preferred method, incorporating sonographic classifications, while MRI and thee-dimensional imaging represent an emerging and promising approach. Imaging helps identify the extent of sinus tracts, assess involvement dimensions in advanced disease stages, and monitor proposed treatments. ^©RSNA, 2024 Supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article.

Since its introduction in 1980, fatty liver disease (now termed metabolic dysfunction-associated steatotic liver disease [MASLD]) has grown in prevalence significantly, paralleling the rise of obesity worldwide. While MASLD has been the subject of extensive research leading to significant progress in the understanding of its pathophysiology and progression factors, several gaps in knowledge remain. In this pictorial review, the authors present the latest insights into MASLD, covering its recent nomenclature change, spectrum of disease, epidemiology, morbidity, and mortality. The authors also discuss current qualitative and quantitative imaging methods for assessing and monitoring MASLD. Last, they propose six unsolved challenges in MASLD assessment, which they term the proliferation, reproducibility, reporting, needle-in-the-haystack, availability, and knowledge problems. These challenges offer opportunities for the radiology community to proactively contribute to their resolution. The authors conclude with a call to action for the entire radiology community to claim a seat at the table, collaborate with other societies, and commit to advancing the development, validation, dissemination, and accessibility of the imaging technologies required to combat the looming health care crisis of MASLD.

Upper tract urothelial carcinoma (UTUC) originates in the renal pelvis or ureters and typically affects elderly patients, with its incidence increasing over the past few decades. UTUC is a distinct clinical entity with more aggressive clinical behavior than that of lower tract urothelial carcinoma. Due to the significant challenge of acquiring an adequate tissue sample for biopsy, comprehensive risk stratification is required for treatment planning, including radical nephroureterectomy and kidney-sparing management. Imaging plays an important integrated role in risk assessment along with endoscopy and pathologic examination. Lifelong surveillance is required after treatment due to the high incidence of recurrent and metachronous tumors. Lynch syndrome is a frequently unrecognized genetic disorder associated with UTUC that warrants specific attention in patient management. UTUC may manifest with diverse imaging findings, including filling defects, wall thickening, and mass-forming lesions. CT urography is the preferred modality for diagnosis and staging or restaging of UTUC, with numerous technical variations. Efforts have been made to optimize image quality and radiation exposure. Due to its poor sensitivity for small lesions, use of MR urography is limited to special clinical scenarios (eg, when patients have contraindications to iodinated contrast agents). Fluorine 18 fluorodeoxyglucose PET helps to detect metastatic lesions. Image-guided biopsy may be considered for uncertain lesions. Radiologists need to be familiar with the imaging findings and their differential diagnoses. ^©RSNA, 2024 Supplemental material is available for this article.