Citations

Background Circulating tumor DNA (ctDNA) has rapidly evolved from a research tool to a clinically applicable biomarker in colorectal cancer (CRC), transforming the assessment of minimal residual disease (MRD) and recurrence risk. The growing availability of commercial assays has complicated test selection and interpretation, particularly for gastroenterologists who increasingly encounter ctDNA data in postoperative and surveillance settings. Methods We conducted a narrative review of the literature using PubMed, Embase, and Cochrane databases from January 2015 through March 2026, prioritizing randomized controlled trials, prospective cohort studies, and clinical practice guidelines relevant to ctDNA applications in CRC. The search employed predefined keyword combinations applied independently to each database. Two authors (A.S. and S.M.) independently screened titles and abstracts against the prespecified inclusion criteria, with disagreements resolved by discussion. Results Tumor-informed assays that analyze patient-specific mutations exhibit high specificity for MRD detection, with serial sampling sensitivity reaching 88% compared to 59% for tumor-agnostic approaches, based on a 2026 systematic review and diagnostic accuracy meta-analysis that pooled data across multiple platforms and settings; the authors note substantial study-level heterogeneity in platform design and patient populations, and results should be interpreted accordingly, but require tissue access and extended processing times. Tumor-agnostic tests are more rapid and accessible, incorporating genomic and epigenomic signals, though they exhibit site-specific sensitivity variations ranging from 100% for liver metastases to 40% for peritoneal recurrence and remain vulnerable to biological confounders such as clonal hematopoiesis (CH). Importantly, ctDNA interpretation is subject to additional biological limitations including tumor shedding variability by anatomical site and disease burden, the timing of sample collection relative to surgery or chemotherapy, platform-specific detection thresholds, and pre-analytical variables such as hemolysis and delayed plasma processing. Randomized evidence supports ctDNA-guided de-escalation of adjuvant therapy in stage II colon cancer, with 5-year follow-up from the DYNAMIC trial demonstrating comparable recurrence-free survival (88% vs. 87%) and overall survival (93.8% vs. 93.3%) despite reduced chemotherapy use. In stage III disease, ctDNA is strongly prognostic, but chemotherapy intensification based solely on molecular positivity has not improved outcomes. This review additionally addresses underexplored areas including ctDNA in rectal cancer and neoadjuvant therapy, the influence of microsatellite instability (MSI) status on assay performance, and disparities in ctDNA access across racial, socioeconomic, and geographic populations. Conclusions For gastroenterologists encountering ctDNA results in postoperative and surveillance settings, three principles should guide practice (i): match assay selection to clinical intent - tumor-informed platforms for MRD-directed adjuvant decisions, tumor-agnostic platforms when tissue is unavailable (ii); interpret results within biological and technical context, accounting for platform-specific sensitivity limitations, biological confounders, and quantitative VAF trajectory rather than binary thresholds; and (iii) integrate ctDNA findings into multidisciplinary pathways - de-escalation is supported by high-quality randomized evidence in stage II disease (Grade A; Level I), while chemotherapy escalation based solely on ctDNA positivity in stage III disease is not supported outside clinical trials (Grade C; Level I). Standardization of assay performance benchmarks and equitable access to testing remain critical unmet needs.

SUMMARY OBJECTIVE: The aim of this study was to estimate the prevalence of isthmocele using transvaginal ultrasound, magnetic resonance imaging and diagnostic hysteroscopy. METHODS: A cross-sectional study conducted from 2020 to 2022 in tertiary academic hospital with ninety non-pregnant women with a history of cesarean section. Transvaginal ultrasound (n=90), magnetic resonance imaging (n=65) and office diagnostic hysteroscopy (n=81) were performed within a short interval for each patient. RESULTS: The women had a mean age of 34.8±6.3 years, mean number of 2.0±1.1 cesarean sections and mean duration of 40 months since their last cesarean. The prevalence of isthmocele with 95%CIs was 11.3% (5.5–19.7%) on transvaginal ultrasound, 66.1% (53.3–77.4%) on magnetic resonance imaging, and 43.2% (32.2–54.6%) on diagnostic hysteroscopy. When transvaginal ultrasound was considered reference, accuracy for diagnostic hysteroscopy was 57.89% (44.1%; 70.6%) and magnetic resonance imaging, 43.86% (30.9; 57.5%); when magnetic resonance imaging was reference, accuracy for diagnostic hysteroscopy was 54.39% (40.75; 67.43%). Agreement analysis (kappa) among the methods showed low scores between diagnostic hysteroscopy and magnetic resonance imaging regarding transvaginal ultrasound (0.126, p<0.001 and 0.103, p<0.001, respectively) and between diagnostic hysteroscopy and magnetic resonance imaging (0.206, p=0.014). CONCLUSION: The prevalence of isthmocele was lower in transvaginal ultrasound and higher in magnetic resonance imaging. Accuracy varied from 43 to 58% among the three methods and agreement between tests for diagnosing isthmocele was low.

OBJECTIVE Severe (level 3) hypoglycemia is a life-threatening complication of diabetes associated with substantial risk of recurrence and long-term morbidity. This study examined how adults with diabetes interpreted severe hypoglycemic events and why they declined participation in a community paramedicine program (Diabetes Rescue, Engagement, and Management [Diabetes-REM]) designed to prevent recurrence. RESEARCH DESIGN AND METHODS We conducted semistructured qualitative interviews with adults with type 1 or type 2 diabetes who experienced severe hypoglycemia requiring emergency medical services and declined enrollment in Diabetes-REM. Interviews explored hypoglycemia management experiences and reasons for nonparticipation and were explored using thematic analysis. RESULTS Sixteen adults (44% female; mean age 60 years, range 25–83) participated. Four interrelated themes emerged. First, participants normalized glucose variability as a baseline condition of diabetes and interpreted severe events as situational and correctable when a cause was identifiable, or as inevitable when it was not, rather than as evidence of increased risk. Second, participants relied on prevention systems encompassing habitual routines, caregiver involvement, and glucose-monitoring technologies. Third, severe episodes were frightening and disruptive but typically prompted adjustments to personal management over pursuit of additional clinical support. Finally, reasons for declining Diabetes-REM included time constraints (56%), perceived lack of benefit (25%), and privacy concerns or discomfort with home visits (25%). CONCLUSIONS Among adults who declined a community paramedicine hypoglycemia prevention intervention, severe events were absorbed into existing self-management frameworks rather than viewed as signals of increased risk. Programs targeting hypoglycemia recurrence should account for patients’ risk perceptions and existing management systems, positioning support as complementary rather than corrective.

Abstract White matter bundles play a crucial role in cognitive functions by rapidly transmitting information between brain regions. Inter-areal conduction guides the integration of information and conduction velocity is a fundamental parameter in theories and models of brain function. However, distributions of conduction velocity remain difficult to characterize in vivo in humans. In this work, we integrated diffusion magnetic resonance imaging (dMRI) tractography with intracranial electrical stimulation during clinical stereo-electroencephalography (sEEG) monitoring in 17 subjects to measure conduction velocity within four major white matter bundles. Our findings reveal that human brain conduction is characterized by high variability both within and between bundles, reflecting a predominance of slow connections alongside rare high-speed connections. Because conduction velocity in myelinated fibers follows an approximately linear relationship with axon diameter, we derive underlying axon diameter distributions and show that these estimates are comparable to previous post-mortem studies. These findings demonstrate a heavily skewed distribution of human neural conduction velocities and show that structural heterogeneity shapes the timing and integration of information in large-scale networks.

Artificial intelligence can be applied across radiology education to enhance curriculum development and delivery through data-driven needs assessment, content and assessment generation, personalized learning, and program evaluation and management.