Fred T. Lee

Background/Objectives: Renal mass biopsy (biopsy) is increasingly incorporated into the evaluation of localized renal masses, yet its role in guiding management remains variable among clinical practices. We evaluated the clinical association of biopsy using a simplified classification system categorizing biopsy results as Biopsy Actionable for Immediate Treatment (BAIT) or Biopsy Actionable for Active Surveillance (BAAS)—assessing how biopsy-derived histology influences real-world management. Methods: We identified all patients undergoing biopsy for a renal mass measuring 2–7 cm at a single academic center between 2010 and 2025. After excluding nondiagnostic biopsies, repeat biopsies, and biopsies performed for metastatic diagnosis, 1395 patients formed the analytic cohort. Histologic subtypes and initial treatment were evaluated. Multivariable logistic regression assessed predictors of (1) radical versus partial nephrectomy, (2) surgery versus thermal ablation, and (3) active surveillance versus intervention, adjusting for tumor diameter, age, and BAIT/BAAS status. Results: Of 1395 patients, 1119 (80.2%) had BAIT pathology and 276 (19.8%) had BAAS pathology. Initial management included surgery (36.3%), thermal ablation (36.3%), active surveillance (24.2%), no treatment (1.7%), and radiation (1.5%). BAAS pathology was strongly associated with the selection of active surveillance (OR 21.80, p < 0.001). Larger tumor diameter was the principal driver of radical nephrectomy (OR 2.04/cm, p < 0.001) and of choosing surgery over ablation (OR 2.05/cm, p < 0.001). Younger age was associated with selection of surgery over ablation (OR 0.93/year, p < 0.001). Biopsy histology showed a stronger association with surveillance selection than either tumor diameter or age. Conclusions: Biopsy provides actionable diagnostic information for patients with 2–7 cm renal masses, identifying benign or indolent pathology in nearly one in five patients. BAIT/BAAS categorization was strongly associated with the selection of active surveillance for renal masses.

Objective: Needle artifact redistribution technique (Needle-ART) is a recently developed image artifact-reduction method for CT-guided needle procedures. The principle of this technique is to create an angle between the needle and imaging plane by tilting the CT gantry, then reformatting images along the needle plane, thus redistributing the artifact out of the viewing plane. The purpose of this study is to evaluate the feasibility, artifact reduction, and clinical applicability of Needle-ART for the placement of biopsy introducer needles into the liver, kidneys, and lungs of a deceased animal model. Methods: A paired before-and-after study was performed in 2 deceased swine to evaluate the effectiveness of Needle-ART in reducing metal artifacts during CT-guided interventions. A 17G co-axial needle was inserted into the liver, kidney, and lung at 6 sites per organ and scanned at each site with both 0-degree gantry tilt (standard axial as the control group) and 6-degree tilted gantry on Needle-ART. A total of 48 scans with 24 control and 24 Needle-ART were collected. Images were reformatted to align with the needle trajectory. Collected images were evaluated for overall artifact severity by 3 blinded radiologists. Results: Needle-ART significantly reduced metal artifacts across all quantitative metrics, which was consistent with blinded reader assessments. Mean artifact length was reduced by 35.5% ( P =0.0019) in liver, 65.9% ( P =0.003) in kidney, and 59.4% ( P =0.0021) in lung. Median artifact width decreased by 30% ( P =0.028) in liver, 24.3% ( P =0.028) in kidney, and 8.3% ( P =0.017) in lung. Median artifact intensity was reduced by 38.8% ( P =0.011) in liver, 35.4% ( P =0.028) in kidney, and 23.6% ( P =0.021) in lung. The radiologists scored conventional CT images (with non-tilted gantry) significantly worse artifacts compared with Needle-ART (with tilted gantry) ( P =0.000041). Conclusions: The off-axis reconstruction method is a novel technique that effectively reduces artifacts by acquiring scans with the CT gantry tilted 6 degrees relative to the plane containing the needle and target.

Background/Objectives: Percutaneous microwave (MW) ablation is a nephron sparing treatment for localized renal cell carcinoma (RCC). We compared perioperative, renal functional, and oncologic outcomes for clinical stage 1 RCC treated with MW ablation, PN, or RN. Methods: Adults with clinical T1 kidney masses treated with MW ablation, PN, or RN from 2001–2025 were identified. Outcomes included: 90-day overall and major complication rate, 30-day readmission rate, length of hospital stay (LOS), change in renal function, local recurrence-free survival (LRFS), metastasis-free survival (MFS), and cancer-specific survival (CSS). Univariable and multivariable analyses evaluated outcomes adjusted for confounders. Results: A total of 2201 patients with renal masses ≤ 7 cm and no evidence of locally advanced or metastatic disease were treated with MW ablation (708), PN (729), or RN (764). MW ablation patients were older and more comorbid compared to both PN/RN, whereas RN patients had larger, higher-grade tumors. Ninety-day overall complications were lowest after MW ablation (8.9% vs. 20.3% PN, p < 0.001 and 8.9% vs. 19.9% RN, p < 0.001). LOS was shortest after MW ablation (median 1 day vs. 3 days PN/RN, p < 0.001 for each). Six-month eGFR decline was similar after MW ablation and PN (−5.2% and −4.7%, p = 0.84) but greater after RN (−32.9%, p < 0.001). Local recurrences were more common with MW ablation, with five-year LRFS 96.4% versus 99.7% for PN (p < 0.001). Five-year MFS (99.5% vs. 99.7%, p = 0.24) and CSS (99.3% vs. 99.7%, p = 0.71) did not differ between MW ablation and PN. Conclusions: Percutaneous MW ablation has comparable metastasis free and cancer specific survival with lower perioperative morbidity and comparable renal preservation to PN, despite worse baseline comorbidity and renal function. These findings support MW ablation as an effective nephron-sparing option for appropriately selected patients with clinical T1 RCC when performed at an experienced center.

Histotripsy is a non-invasive, non-thermal, and non-ionising focused ultrasound (US) treatment method that destroys tissue through...