森 墾

BACKGROUND: Computer-aided detection (CAD) systems for chest radiographs are widely used; however, concurrent reader displays such as bounding-box (BB) highlights may influence interpretation. This pilot study used eye tracking to examine which aspects of visual search were affected by these factors. METHODS: We sampled 180 chest radiographs from the VinDR-CXR dataset: 120 with solitary pulmonary nodules or masses and 60 without. BBs were configured for 80 % display sensitivity and specificity. Three radiologists (with 11, 5, and 1 years of experience) interpreted each case twice-once with BBs visible and once without-after a ≥ 2-week washout. Eye movements were recorded using an EyeTech VT3 Mini. Metrics included interpretation time, time to first fixation, lesion dwell time, total gaze-path length, and lung-field coverage. Outcomes were modeled using a linear mixed model with the reading condition set as a fixed effect and case and reader as random intercepts. Primary analysis was restricted to true positives (n = 96). RESULTS: Concurrent BB display prolonged interpretation time by 4.9 s (p < 0.001) and increased lesion dwell time by 1.3 s (p < 0.001). Total gaze-path length increased by 2076 pixels (p < 0.001), and lung-field coverage increased by 10.5 % (p < 0.001). The time to first fixation was reduced by 1.3 s (p < 0.001). CONCLUSION: Eye tracking revealed measurable changes in search behavior associated with concurrent BB display during chest radiograph interpretation. These findings support this approach and highlight the need for larger studies across modalities and clinical contexts.

PURPOSE: Bone oligometastases are increasingly recognized as a clinical entity that may benefit from local therapies. Stereotactic body radiation therapy (SBRT) enables the delivery of high-dose, precise irradiation and has shown promising results in improving local control (LC) and survival. However, prognostic factors influencing LC after SBRT in patients with bone oligometastases treated with curative metastasis-directed intent remain unclear. METHODS AND MATERIALS: We retrospectively analyzed 58 patients with 68 bone oligometastatic lesions treated with SBRT between March 2021 and December 2023. Radiation therapy protocols were determined according to lesion site, and follow-up imaging was performed every 3 months. Overall survival was evaluated using the Kaplan-Meier method, and LC was assessed using a competing risk model. Prognostic factors for LC were investigated using univariate and exploratory multivariable analyses, with gross tumor volume (GTV) cutoffs determined by receiver operating characteristic analysis using local recurrence as the endpoint. RESULTS: The median follow-up duration was 25 months. The 1- and 2-year overall survival rates were 95% and 80%, respectively. The 1- and 2-year LC rates were 86.1% and 80.3%, respectively. Upon exploratory multivariable analysis, a GTV ≥ 12 cc was identified as an independent predictor of local recurrence (adjusted hazard ratio, 8.77; 95% CI, 1.10-70.2; P = .041). Lesions with GTV ≥ 12 cc had significantly lower LC rates than those with GTV < 12 cc (Gray's test, P = .013). No grade ≥3 treatment-related adverse events were observed. CONCLUSIONS: SBRT for bone oligometastases provides excellent LC and survival with minimal toxicity. Larger tumor volume, as assessed by GTV, was associated with a higher risk of local recurrence in this cohort. Further studies are warranted to validate these findings and to explore volume-adapted treatment strategies.

Abstract Background Large-scale CT-based reference standards for abdominal organ volume, incorporating age, sex, and body size, are limited. Purpose To establish sex- and age-specific reference distributions for major abdominal organ volumes on non-contrast abdominopelvic CT in a nationwide Japanese cohort to provide a foundation for automated clinical assessment and dose optimization. Materials and Methods In this retrospective, multicenter study, using the Japan Medical Image Database, we identified all non-contrast abdominopelvic CT examinations performed in 2024. Unique adults with available data on age, sex, height, and weight were included in this study. The final sample comprised 49,764 examinations (26,456 men and 23,308 women) conducted at nine institutions. Automated segmentation (TotalSegmentator v2.10.0) was used to produce organ volumes, excluding hollow viscera. The sex-specific 10th, 25th, 50th, 75th, and 90th percentiles were calculated. Age–volume relationships of body surface area (BSA)-normalized volumes (mL/m ² ) were modeled using natural cubic splines (four degrees of freedom) separately by sex. Results Median (mL) male vs female volumes were as follows: liver, 1194.7 vs 1024.0; pancreas, 63.6 vs 52.2; spleen, 118.1 vs 95.1; kidneys (total), 268.3 vs 221.2; adrenals (total), 6.6 vs 4.2; iliopsoas (total), 483.4 vs 317.7; prostate, 24.9 (men only). Age–volume relationships of BSA-normalized volumes showed convex patterns for the liver, pancreas, and kidneys in both sexes and for male adrenal glands; lower values in older age groups for the spleen and iliopsoas in both sexes; and higher values in older age groups for the prostate and female adrenal glands. Conclusion This nationwide Japanese CT cohort provides sex- and age-resolved volumetric reference standards. These standards enable objective identification of abnormalities, support personalized medicine, and facilitate automated AI-based reporting to reduce radiologist workload and optimize radiation dose protocols. Key Results Median volumes (men vs women, mL): liver 1195/1024; pancreas 64/52; spleen 118/95; kidneys 268/221; adrenals 6.6/4.2; iliopsoas 483/318; prostate 25. Body surface area–normalized age–volume relationships were convex for liver, pancreas, and kidneys in both sexes and for male adrenal glands. Spleen and iliopsoas declined monotonically with age in both sexes, whereas prostate and female adrenal glands increased monotonically.

Acetabular fractures are usually caused by high-energy trauma, and seizure-induced cases resulting from strong muscle contractions are extremely rare. We report the case of a 90-year-old man with osteoporosis who incurred a nontraumatic acetabular fracture during a seizure. Computed tomography revealed an internal iliac artery injury, which was promptly treated with transcatheter arterial embolization. As such vascular injuries, though rare, require early diagnosis and treatment, radiologists must be aware of the associated imaging findings and management, particularly in cognitively impaired patients.