Radiology最新文献

Background Reducing the radiation dose without compromising image quality or diagnostic accuracy is essential for repeat CT monitoring in emphysema. Purpose To evaluate the accuracy of ultra-low-dose (ULD) photon-counting CT (PCCT) for both visually and quantitatively assessing emphysema, and to compare this accuracy with that of low-dose (LD) PCCT. Materials and Methods Participants with emphysema who underwent same-day LD and ULD PCCT between November 2024 and February 2025 were prospectively included. Two radiologists independently evaluated the image quality parameters (overall image quality, sharpness, artifacts, and noise) and visually assessed emphysema (subtype and severity). Automated emphysema quantification was performed using low-attenuation volume (LAV) analysis. For centrilobular emphysema (CLE), automated LAV measurements were converted to severity grades and compared with visual severity grades. Paired t tests, Cohen κ analysis, and intraclass correlation coefficients were used to evaluate differences and agreement in findings at LD and ULD PCCT. Results In 152 participants (median age, 68 years [IQR, 60-72 years]; 139 male participants), the ULD protocol reduced radiation exposure by 87% compared with the LD protocol (mean effective dose, 0.20 mSv ± 0.03 [SD] vs 1.58 mSv ± 0.39; P < .001). There was no evidence of a difference between the two protocols in overall image quality (median score, 4 [IQR, 4-5] for both; P = .16), sharpness (median score, 4 [IQR, 4-5] for both; P = .08), or artifacts (median score, 4 [IQR, 3-4] for both; P = .39), but ULD images had lower noise scores (ie, more noise) than LD images (median score, 3 [IQR, 3-3] vs 4 [IQR, 4-4]; P < .001). There was excellent agreement between the two protocols for grading of visual CLE severity (weighted κ = 0.98) and paraseptal emphysema severity (κ = 0.96). The two protocols exhibited excellent agreement in LAV measurements across the lungs and for individual lung lobes (intraclass correlation coefficient range, 0.96-0.98). Visual CLE severity grades demonstrated good agreement with LAV measurements for both the LD (weighted κ = 0.73) and ULD (weighted κ = 0.75) protocols. Conclusion PCCT enables accurate visual and automated assessments of emphysema at a radiation dose equivalent to that of two chest radiographs without compromising image quality. © RSNA, 2026 Supplemental material is available for this article.

Background Previous clinical trials have supported the use of endovascular therapy (EVT) for basilar artery occlusion (BAO) stroke within 24 hours of symptom onset. However, the safety and effectiveness of EVT in patients with BAO treated beyond 24 hours remains unclear. Purpose To compare clinical outcomes and safety following EVT combined with standard medical care versus medical care alone in patients with acute ischemic stroke due to BAO treated beyond 24 hours from symptom onset. Materials and Methods This multicenter retrospective study enrolled patients between March 2017 and April 2024 across China. Eligible patients had BAO and were treated with EVT or standard medical care beyond 24 hours from symptom onset. The primary outcome was the proportion of patients achieving good functional status (modified Rankin Scale score, 0-3). Primary safety outcomes included 90-day mortality and symptomatic intracranial hemorrhage. Inverse probability-weighted regression was performed to adjust for prespecified clinical characteristics, and instrumental variable analysis was repeated as sensitivity analysis. Results Among 217 patients (median age, 66 years [IQR, 58-73 years]; 160 men), good functional status at 90 days was achieved in 35.7% (46 of 129) of patients who underwent EVT and 26.1% (23 of 88) of controls (inverse probability of treatment weighting [IPTW]-adjusted risk ratio [RR], 1.67; P = .008), which was confirmed by instrument variable analysis (adjusted RR, 2.18; P = .04). There was no evidence of a difference in mortality at 90 days between EVT and control groups (48.1% [62 of 129 patients] vs 54.6% [48 of 88 patients]; IPTW-adjusted RR, 0.80; P = .10). Risk of symptomatic intracranial hemorrhage was higher in EVT compared with control groups (11.9% [15 of 126 patients] vs 1.3% [one of 80 patients]; IPTW-adjusted RR, 11.01; P = .02). Conclusion In this study of patients with BAO treated beyond 24 hours from symptom onset, EVT was associated with higher odds of good functional status at 90 days compared with standard medical care, albeit with increased odds of symptomatic intracranial hemorrhage. Chinese Clinical Trial Registry no. ChiCTR2000041117 © RSNA, 2026 Supplemental material is available for this article.

Background Women with high background parenchymal enhancement (BPE) at contrast-enhanced MRI have up to a fourfold increased risk of breast cancer, even after adjusting for breast density. However, no studies have examined BPE specifically among Black women, despite their higher breast cancer-specific mortality and typically lower breast density. Purpose To examine Black-White racial differences in contrast-enhanced MRI-derived BPE. Materials and Methods This retrospective cross-sectional study examined the data of Black and White women without a history of breast cancer who underwent both mammography and subsequent MRI as part of a screening or diagnostic workup between January 2016 and December 2023. BPE was assessed qualitatively according to the Breast Imaging Reporting and Data System as high (ie, moderate or marked) or low (ie, minimal or mild). Logistic regression was performed to assess the association between race and high BPE, and mediation analysis was performed to explore the extent to which density accounted for racial differences in BPE. Results A total of 388 Black women and 2101 White women were included, with mean ages of 47 years ± 10 [SD] and 48 years ± 11, respectively. Fewer Black women had extremely dense breasts at mammography (43 of 388 [11%] vs 435 of 2101 [21%]; P = .01). The proportions of both groups exhibiting high BPE at breast MRI were similar (38% vs 33%; P = .11). According to mediation analysis, Black women were 31% more likely to have high BPE levels after density differences were eliminated (odds ratio, 1.28; 95% CI: 1.01, 1.64; P = .03). Conclusion In this preliminary examination of BPE as a breast MRI marker for the risk of invasive breast cancer, Black women were more likely than White women to have high BPE, despite the latter typically having greater breast density.

History: A 66-year-old man with a history of hypertension presented with left-sided jaw jerking, repetitive movements, aphasia, and dysarthria. He was afebrile and in no acute distress, with mild hypertension (153/81 mm Hg). Routine laboratory studies were unremarkable. Brain MRI showed multiple nonenhancing supratentorial, cortical, and subcortical hyperintensities on T2-weighted fluid-attenuated inversion recovery images, which were nonspecific for infectious, inflammatory, vascular, or neoplastic etiologies. CT of the chest, abdomen, and pelvis and MRI of the cervical and thoracic spine were unremarkable. CT angiography of the head and neck showed no areas of stenosis or occlusion. Extensive infectious, autoimmune, and paraneoplastic serologic tests were negative, including serum acetylcholinesterase, antinuclear antibody, erythrocyte sedimentation rate, C-reactive protein, aquaporin 4 and myelin oligodendrocyte glycoprotein (MOG) antibodies, treponemal testing, Tropheryma whipplei, human immunodeficiency virus, tick-borne disease panel, and COVID-19. Lumbar puncture showed 2% neutrophils (reference range, <6%), with normal protein and glucose levels. Cerebral spinal fluid studies, including protein electrophoresis, JC virus, herpes simplex virus polymerase chain reaction, MOG antibodies, cytologic examination, and a paraneoplastic panel (Table), were negative. The patient was treated with nicardipine and levetiracetam, with clinical improvement. A presumptive clinical diagnosis of posterior reversible encephalopathy syndrome was made, with plans for short-interval surveillance imaging and possibly brain biopsy, which the patient initially declined. He was subsequently lost to follow-up. Three years later, he experienced several months of progressive mood alterations followed by the development of psychosis and two generalized tonic-clonic seizures. At readmittance, he was again afebrile and in no acute distress, with mild hypertension (150/70 mm Hg). His neurologic examination was remarkable only for symmetric hyperreflexia. Repeat laboratory testing, including human immunodeficiency virus and hepatitis serologic tests, remained negative. Lumbar puncture showed 1% neutrophils, with normal protein and glucose levels and absent oligoclonal bands. MOG antibodies and an autoimmune encephalitis panel (Table) were negative. Repeat brain MRI was performed (Figs 1-3).

History: A previously healthy 33-year-old woman presented with several months of intermittent right upper quadrant discomfort, early satiety, bloating, and nausea. She had no remarkable past medical or surgical history, specifically no known malignancy, chronic liver disease, or substance abuse. She had four biologic children and reported no current or prior oral contraceptive use. Physical examination revealed normal vital signs and a soft, nontender abdomen. Laboratory studies included a hepatic function panel, which was normal. Results for serum tumor marker tests included an α-fetoprotein level of 2.1 μg/L (reference range, ≤8.3 μg/L), a carcinoembryonic antigen level less than 0.6 μg/L (reference range, ≤5.0 μg/L), and a cancer antigen 19-9 level of 17.4 kU/L (reference range, ≤35.0 kU/L). A urine pregnancy test was negative. CT of the abdomen and pelvis with intravenous contrast material was performed. No extrahepatic pathologic features were identified. MRI of the abdomen without and with intravenous contrast material was performed, for further evaluation of the liver findings.