Needle Gauge Safety Assumptions Are Obsolete in the Coaxial Era: Multivariable Evidence Supporting a “Yield-First” Strategy in 264 CT-Guided Lung Biopsies

The paradigm shift toward precision oncology has increased demands on lung biopsy, with pathologists requiring larger core volumes for next-generation sequencing (NGS) and biomarker analysis. Despite this, many interventional radiologists remain hesitant to use 18-gauge systems due to historical associations with increased pneumothorax risk. We hypothesized that in a standardized coaxial workflow, needle gauge is no longer an independent determinant of adverse events (AEs), supporting a yield-first approach to gauge selection.

Materials and Methods:

We performed a retrospective cohort study of 264 consecutive CT-guided lung biopsies (CTLB) conducted between October 2023 and October 2025 at a tertiary referral center. All procedures employed a standardized coaxial technique with breath-hold coaching. Cases were stratified by introducer gauge: 18-gauge (n=143) or 20-gauge (n=121). Primary outcomes were pneumothorax and pulmonary hemorrhage, graded per Society of Interventional Radiology (SIR) criteria. Multivariable logistic regression adjusted for lesion size, mid-needle-to-pleura distance, lobar location, patient age, and tract embolization.

Results:

The overall pneumothorax rate was 25.8% (68/264), consistent with international benchmarks, with an unplanned admission rate of 2.5% (7/264). Pneumothorax rates did not differ between 18-gauge and 20-gauge systems (24.5% vs 27.3%; p=0.67). Pulmonary hemorrhage occurred more frequently in the 20-gauge group (17.4% vs 3.5%; p< 0.001). Selection bias was evident, with 20-gauge needles used for smaller lesions (27.1mm vs 34.2mm; p=0.002). After adjustment, needle gauge was not an independent predictor of pneumothorax (adjusted OR [aOR] 1.38, 95% CI 0.76-2.52; p=0.29). The association between 20-gauge needles and hemorrhage persisted (aOR 7.64, 95% CI 2.53-23.02; p< 0.001), reflecting lesion complexity rather than intrinsic device risk.

Conclusion:

In a standardized coaxial CTLB program, increasing needle caliber to 18-gauge does not independently increase pneumothorax risk. The historical safety signal against larger needles is mitigated by coaxial technique mechanics. These findings support an 18-gauge default strategy to optimize molecular yield, reserving smaller gauges for specific anatomical constraints rather than perceived safety advantages. During manuscript preparation, the authors used ChatGPT (version 5.1; OpenAI) to assist with readability, spelling, and grammar. The authors reviewed and edited the manuscript in full and take complete responsibility for its content.