Canadian Association of Radiologists Journal-Journal De L Association Canadienne Des Radiologistes最新文献

Introduction: The carbon footprint of imaging equipment in radiology is high, but the impact of patient travel for imaging is unclear. This study aimed to quantify distances traveled by ambulatory patients for outpatient MRI, determine the proportion traveling beyond their nearest MRI facility, and estimate the associated excess carbon dioxide equivalent (CO₂e) emissions.

Methods: With research ethics board approval, we retrospectively analyzed provincial MRI data from 2023. Distances from patient home address to the nearest and attended MRI facilities were calculated. CO₂e estimates were derived using an online tool (www.carbonfootprint.com/calculator.aspx) with average vehicle size and emissions.

Results: In 2023, 40 062 provincial MRI scans were performed; isolating single visits for adult patients yielded 27 755 data points. Of these, 19.5% (n = 5400) traveled beyond their nearest MRI facility. Mean round-trip travel was 60.4 km for those attending their nearest site versus 295.6 km for those traveling further (P < .0001). The excess travel produced ~288 metric tons of additional CO₂e, equivalent to emissions from 61 large-size gasoline-powered cars driven for 1 year or carbon sequestered by 4762 tree seedlings grown for 10 years.

Conclusion: Nearly one-fifth of patients traveled farther than necessary for MRI, generating substantial avoidable emissions. Aligning MRI service distribution with population density could lessen the environmental impact of medical imaging.

Objectives: Local tumor progression (LTP) after percutaneous ablation of small renal cell carcinoma (RCC) is suspected when new enhancing or enlarging soft tissue appears within the ablation zone. Benign post-treatment changes can mimic this finding. This study compares the incidence and imaging characteristics of non-malignant changes (NMC) versus LTP after renal ablation.

Materials and methods: In this single-center, retrospective study, all patients with RCC treated with radiofrequency ablation (RFA) from February 2004 to May 2016 were identified. Post-ablation imaging reports from through May 2017 were reviewed to detect findings suspicious for LTP. Patients with suspicious findings underwent clinical, imaging, and histopathologic follow-up through May 2025 to determine the reference diagnosis. Imaging features were categorized by morphology, location within the ablation zone, and enhancement pattern.

Results: Among 256 patients (mean age 65.6 years ± 10.8, 193 men) with 268 treated tumors, 18 tumors (6.7%) developed suspicious imaging findings. Eight tumors (3.0%) were classified as NMC and 10 tumors (3.7%) as LTP. NMC had significantly lower CT enhancement than LTP (31 vs 152 HU, P < .001). Lesions along the renal parenchymal margin were exclusively associated with LTP (9/9), whereas abnormalities at the extrarenal margin or centrally within the ablation zone were predominantly NMC (8/9). Enhancement with washout was seen only in LTP.

Conclusion: Non-malignant post-ablation changes can mimic LTP and occur with similar frequency. Imaging features can help differentiate benign changes from local tumor progression and reduce unnecessary re-interventions.

Background: Negative appendicectomies in children can be associated with morbidity. MRI has become a radiation-free alternative to CT to assist in the diagnosis of paediatric appendicitis, particularly when ultrasound is equivocal. A systematic review and meta-analysis were performed to assess the diagnostic accuracy of MRI for paediatric appendicitis and its role in reducing negative appendicectomy rates (NAR).

Methods: Searches were performed across PubMed, Embase, Cochrane Library, Scopus, Web of Science, for studies from 1 January 2000 to 31 July 2025. The inclusion criteria were studies of children (<18 years) with suspected appendicitis undergoing MRI. Bivariate random-effects meta-analyses were performed. Meta-regression explored the impact of covariates for example, DWI, contrast use, image reviewer blinding, and magnetic field strength.

Results: Twelve studies (n = 3242) met inclusion. Pooled MRI sensitivity was 96.7% (95% CI: 93.4%-98.9%), specificity 97.9% (95% CI: 95.6%-99.3%). MRI NARs ranged from 0.66% to 11.1%, with 3/12 studies reporting NARs <5%. Meta-regression showed non-significant associations between NAR and DWI use (+3.12%, P = .264), MRI contrast use (-5.64%, P = .110), and magnetic field strength (-1.63% per Tesla, P = .361). No significant publication bias was detected (Deeks' P = .152).

Conclusion: MRI demonstrates high diagnostic accuracy and is associated with low negative appendicectomy rates in children. Its use is particularly effective where ultrasound/clinical findings are inconclusive as MRI overcomes ultrasound limitations, poor appendix visualisation, operator-dependence, and inability to exclude alternate diagnoses. Given its radiation-free nature and CT-like diagnostic performance, wider adoption of MRI within paediatric appendicitis pathways may help avoid surgery and reduce exposure to ionising radiation.

Background: Reduced field-of-view (rFOV) T2WI improves in-plane spatial resolution. Deep learning-based reconstruction (DLR) has emerged as enhancing image quality. We compared examination time, image quality, and lesion detection rates between pancreaticobiliary rFOV T2WI with and without DLR.

Methods: 198 patients who underwent pancreaticobiliary rFOV T2WI were included. The protocol included rFOV T2WI with 2 NEX (rFOV T2WI_N2) and 1 NEX (rFOV T2WI_N1). DLR was applied to generate corresponding datasets: rFOV T2WI_N2-DLR and rFOV T2WI_N1-DLR datasets. Three observers evaluated the noise, respiratory motion artifacts (RMA), overall image quality (OIQ), and diagnostic confidence (DC). Two observers measured the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). Image quality metrics were compared using either ANOVA or Friedman test. Lesion detection rates were tested using the Cochran's Q test and McNemar test.

Results: The noise, RMA, OIQ, and DC scores of rFOV T2WI_N1-DLR were notably higher than those of rFOV T2WI_N1. The noise, OIQ, and DC scores of rFOV T2WI_N2 were notably higher than those of rFOV T2WI_N1 (P < .001). The SNR and CNR of rFOV T2WI with DLR were notably higher than those of rFOV T2WI without DLR (P < .05). The rFOV T2WI_N1-DLR sequence yielded a higher lesion detection rate (92.5%; 491/531) compared to rFOV T2WI_N1 (76.5%; 406/531).

Conclusions: Pancreaticobiliary rFOV T2WI with DLR is feasible and yields superior image quality compared to rFOV T2WI without DLR. A 37.1% to 74.4% reduction in acquisition time is achievable without increasing image noise or compromising overall image quality and lesion detection rate.

Relevance statement: The perfect balance of image quality, scanning time, and lesion detection rate can be achieved by using DLR in pancreaticobiliary rFOV T2WI.

Serous cystadenoma (SCA) is the most common benign cystic lesion of the pancreas, often an incidental finding on CT scans. Despite their characteristic features such as microcystic or honeycomb appearance, central scar, or lobulated margins, SCAs can display a range of morphologies, complicating their diagnosis and leading to potential confusion with premalignant or malignant lesions. Cinematic rendering (CR), a recent three-dimensional technique, producing striking lifelike images and enhancing visualization of subtle internal structures compared to conventional imaging. In this review, we demonstrate how CR improves the depiction of microcystic, honeycomb, macrocystic, and solid SCA patterns, as well as atypical features that can mislead radiologists. To the best of our knowledge, this is the first review to highlight CR's ability to define the full spectrum of SCA appearances on CT. Case examples illustrate how CR accentuates tissue textures, clarifies spatial and vascular relationships, and highlights details such as septations and calcification. By refining assessment of internal and external lesion characteristics, CR has the potential to augment standard CT and facilitate accurate differentiation from other pancreatic lesions, reducing unnecessary interventions.