Reducing contrast-agent volume and radiation dose in CT with 90-kVp tube voltage, high tube current modulation, and advanced iteration algorithm.

Increasing utilization of computed tomography (CT) has raised concerns regarding CT radiation dose and technology has been developed to achieve an appropriate balance between image quality, radiation dose, and the amount of contrast material. This study was planned to evaluate the image quality and radiation dose in pancreatic dynamic computed tomography (PDCT) with 90-kVp tube voltage and reduction of the standard amount of contrast agent, compared with 100-kVp PDCT of the research hospital's convention. Total of 51 patients with both CT protocols were included. The average Hounsfield units (HU) values of the abdominal organs and image noise were measured for objective image quality analysis. Two radiologists evaluated five categories of image qualities such as subjective image noise, visibility of small structure, beam hardening or streak artifact, lesion conspicuity and overall diagnostic performance for subjective image quality analysis. The total amount of contrast agent, radiation dose, and image noise decreased in the low-kVp group, by 24.4%, 31.7%, and 20.6%, respectively (p < 0.001). The intraobserver and interobserver agreements were moderate to substantial (k = 0.4-0.8). The contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR), and figure of merit of the almost organs except psoas muscle in the low-kVp group were significantly higher (p < 0.001). Except for lesion conspicuity, both reviewers judged that subjective image quality of the 90-kVp group was better (p < 0.001). With 90-kVp tube voltage, 25% reduced contrast agent volume with advanced iteration algorithm and high tube current modulation achieved radiation dose reduction of 31.7%, as well as better image quality and diagnostic confidence.

Acute Ileal Diverticulitis: Computed Tomography and Ultrasound Findings.

BACKGROUND: Acute ileal diverticulitis is a rare disease mimicking acute appendicitis. Inaccurate diagnosis with a low prevalence and nonspecific symptoms leads to delayed or improper management. METHODS: This retrospective study aimed to investigate the characteristic sonographic (US) and computed tomography (CT) findings with clinical features in seventeen patients with acute ileal diverticulitis diagnosed between March 2002 and August 2017. RESULTS: The most common symptom was abdominal pain (82.3%, 14/17) localized to the right lower quadrant (RLQ) in 14 patients. The characteristic CT findings of acute ileal diverticulitis were ileal wall thickening (100%, 17/17), identification of inflamed diverticulum at the mesenteric side (94.1%, 16/17), and surrounding mesenteric fat infiltration (100%, 17/17). The typical US findings were outpouching diverticular sac connecting to the ileum (100%, 17/17), peridiverticular inflamed fat (100%, 17/17), ileal wall thickening with preserved layering pattern (94.1%, 16/17), and increased color flow to the diverticulum and surrounding inflamed fat on color Doppler imaging (100%, 17/17). The perforation group had a significantly longer hospital stay than non-perforation group (p = 0.002). In conclusion, acute ileal diverticulitis has characteristic CT and US findings that allow radiologists to accurately diagnose the disease.

Comparison between Two-Dimensional and Point Shear Wave Elastography Techniques in Evaluating Liver Fibrosis Using Histological Staging as the Reference Standard: A Prospective Pilot Study.

Evaluation of hepatic fibrosis is essential to prevent liver-related morbidity and mortality. Although various types of ultrasound shear wave elastography (SWE) have been used and validated, there are limited studies on the relatively newer technique, two-dimensional SWE (2D-SWE). Therefore, this study aimed to compare the diagnostic performances of 2D-SWE and point SWE (p-SWE) for evaluating liver fibrosis using histology as the reference standard. To measure liver stiffness (LS) values, 87 patients underwent 2D-SWE and p-SWE using the same machine. Technical failures and unreliable measurements were also evaluated. The diagnostic performances of 2D-SWE and p-SWE were compared using area under the receiver operating characteristic (AUROC) curve analysis. No technical failures were observed in either method; however, unreliable measurements were less frequent in 2D-SWE (1/87 [1.1%]) than in p-SWE (8/87 [9.2%]) (p < 0.001). The AUROC of the LS values of 2D-SWE were significantly higher than those of p-SWE for diagnosing significant fibrosis (0.965 vs. 0.872, p = 0.022) and cirrhosis (0.994 vs. 0.886, p = 0.042). In conclusion, 2D-SWE is more reliable and accurate than p-SWE for diagnosing hepatic fibrosis.

The present situation of and challenges in research ethics and integrity promotion: Experiences in East Asia.

As relatively new economies to the global research arena, East Asian nations have fully realized the importance of research integrity in recent decades. This article conducts document analysis to demonstrate and discuss the current situation of research integrity campaigns in Taiwan, Korea, and Japan, nations that have similar cultural backgrounds and socioeconomic statuses. This article emphasizes the common situations faced by these three nations both individually and collectively. Based on a four-pillar framework, research integrity campaigns in these nations are making progress in terms of policies and regulations, institutional management, researchers' education and training, and the handling of misconduct cases. Various issues and challenges have also emerged in this context, although these efforts may have had positive impacts on research communities in these three nations. Challenges associated with research integrity governance, institutional willingness, RCR instructor qualifications, the effectiveness of education, and the standardization of definitions of misconduct and noncompliance are also highlighted. The issues discussed in this article are expected to have implications for research communities and policy-makers in these three nations as well as in a global context.

Clinical characteristics of patients with COVID-19 vaccine-related pneumonitis: a case series and literature review.

BACKGROUND/AIMS: Pulmonary toxicities of coronavirus disease 2019 (COVID-19) vaccination are exceedingly rare. However, there are a few reported cases after mRNA vaccination, especially from Asian countries. The purpose of this study was to report the clinical characteristics of patients with COVID-19 vaccine-related pneumonitis (CV-P) and to review cases reported in the literature. METHODS: We performed a prospective, observational case series analysis. RESULTS: Eleven patients with a median age of 80 years were enrolled. Ten patients developed CV-P after BNT162b2-mRNA vaccination and one after ChAdOx1 nCoV-19 vaccination. We identified various patterns of CV-P, including transient infiltration, life-threatening acute respiratory distress syndrome, and aggravation of underlying interstitial lung disease. Most patients showed favorable outcomes with good responses to corticosteroid therapy. CONCLUSION: Identifying the mechanism of CV-P requires further investigation; however, radiological and laboratory findings in our case series support inflammatory dysregulation in the lung parenchyma after vaccination. Clinicians should consider CV-P in patients with atypical lung infiltration, no specific etiologies, and recent COVID-19 vaccination.

High-flow arteriovenous fistula and myocardial fibrosis in hemodialysis patients with non-contrast cardiac magnetic resonance imaging.

Background: The role of high-flow arteriovenous fistula (AVF) in cardiovascular morbidity in hemodialysis (HD) patients is very likely under-recognized. We assessed the relationship between high access flow (Qa) and myocardial fibrosis in HD patients. Methods: Myocardial fibrosis was assessed by native T1 relaxation times on non-contrast cardiac magnetic resonance imaging and a potential marker of fibrosis. Serum levels of galectin-3, N-terminal pro-B-type natriuretic peptide (NT-proBNP), and monocyte chemoattractant protein 1 (MCP-1) were measured in 101 HD patients who underwent regular monitoring of AVF Qa. A high-flow AVF was defined as a Qa >2 L/min. Results: Hemodialysis patients showed significantly higher galectin-3 value and increased T1 relaxation time compared to healthy volunteers, suggesting increased myocardial fibrosis in uremic cardiomyopathy. In HD patients, 20 (19.8%) had a Qa > 2L/min, and they had significantly higher cardiac output, cardiac index, left ventricular mass, and increased T1 times than those with a Qa ≤ 2 L/min. Also, serum galectin-3 and NT-proBNP levels were much higher in the high Qa group, indicating a close relationship between the high Qa, increased myocardial fibrosis, and the risk of heart failure (HF) in HD patients. It is interesting that a higher AVF Qa for myocardial fibrosis was independent of several traditional cardiovascular risk factors as well as serum levels of NT-proBNP and MCP-1. Conclusions: A supra-physiologically high Qa can be related to myocardial fibrosis and increased risk of HF in HD patients. Regular Qa monitoring could allow early detection of a high-flow AVF that could arise cardiac complications.

Comparison of diagnostic accuracy of 2D and 3D measurements to determine opportunistic screening of osteoporosis using the proximal femur on abdomen-pelvic CT.

OBJECTIVES: To compare the osteoporosis-predicting ability of computed tomography (CT) indexes in abdomen-pelvic CT using the proximal femur and the reliability of measurements in two- and three-dimensional analyses. METHODS: Four hundred thirty female patients (age range, 50-96 years) who underwent dual-energy X-ray absorptiometry and abdominal-pelvic CT within 1 month were retrospectively selected. The volumes of interest (VOIs) from the femoral head to the lesser trochanter and the femoral neck were expressed as 3DFemur. Round regions of interest (ROIs) of image plane drawn over the femoral neck touching the outer cortex were determined as 2Dcoronal. In HU histogram analysis (HUHA), the percentages of HU histogram ranges related to the ROI or VOI were classified as HUHAFat (<0 HU) and HUHABone (126 HU≤). Diagnostic performance, correlation analysis and measurement reliability were analyzed by receiver operating characteristic curves, correlation coefficient and interobserver correlation coefficient (ICC), respectively. RESULTS: AUCs of each HUHA and mean-HU measurement on 2D-ROI and 3D-VOI were 0.94 or higher (P < 0.001). Both 3DFemur-Mean-HU and 3DFemur-HUHABone showed the highest AUC (0.96). The cut-off value of 3DFemur-Mean-HU was 231HU or less, (sensitivity: 94.8%; specificity: 85.0%; correlation coefficient: -0.65; P <0.001) for diagnosis of osteoporosis. There was no superiority between AUCs in 2D-ROI and 3D-VOI measurements (P > 0.05). Reliability of the 3D-VOI measurement showed perfect agreement (ICC ≥ 0.94), and 2D-ROI showed moderate to good agreement (ICC range: 0.63~0.84). CONCLUSIONS: CT indexes on 3D-VOI for predicting femoral osteoporosis showed similar diagnostic accuracy with better reproducibility of measurement, compared with 2D-ROI.

Unusual, but important, peri- and extra-articular manifestations of rheumatoid arthritis: a pictorial essay.

Ultrasonography is a useful technique to detect soft tissue changes of rheumatoid arthritisnot only synovitis, but also tenosynovitis, bursitis, and enthesitis-even at a subclinical stage. However, radiologists tend to focus on synovitis in daily practice, and unusual peri- or extraarticular manifestations of rheumatoid arthritis are difficult to detect at the initial presentation. This pictorial essay describes a broad spectrum of ultrasonographic findings in tendons, bursae, ligaments, subcutaneous tissues, bones, and nerves to assist in the accurate diagnosis of rheumatoid arthritis.

Influence of the Reaction Pathway on the Defect Formation in a Cu2ZnSnSe4 Thin Film.

Point defect engineering in Cu2ZnSnSe4 (CZTSe) thin films is the main issue to improve its device performance. This study reveals the correlation between the reaction pathway and the point defects in the CZTSe film. The reaction pathway from a metallic precursor (Mo/Zn/Sn/Cu) to a kesterite CZTSe film is varied by changing the annealing process. The synthesized CZTSe films under different reaction pathways induce different device performances with different defect energy levels, although all CZTSe films have similar structural and optical properties (Eg ∼ 1.0 eV). The admittance spectroscopy demonstrates the correlations between point defect types (VZn, ZnSn, ZnCu, CuZn, and VCu) and the reaction pathways for the formation of CZTSe films. The different growth rates of binary selenides, such as ZnSe and/or Sn-Se phases, during the annealing process are especially strongly related to the formation of point defects, leading to the different open-circuit voltages (396-451 mV) and fill factors (51-65%). The results of this study suggest that controlling the reaction pathway is an effective approach to adjust the formation of defects in the kesterite CZTSe film as well as to fabricate high-performance solar cell devices.

A Facile Process for Partial Ag Substitution in Kesterite Cu2ZnSn(S,Se)4 Solar Cells Enabling a Device Efficiency of over 12.

A cation substitution in Cu2ZnSn(S,Se)4 (CZTSSe) offers a viable strategy to reduce the open-circuit voltage (Voc)-deficit by altering the characteristics of band-tail states, antisite defects, and related defect clusters. Herein, we report a facile single process, i.e., simply introducing a thin Ag layer on a metallic precursor, to effectively improve the device characteristics and performances in kesterite (Agx,Cu1-x)2ZnSn(Sy,Se1-y)4 (ACZTSSe) solar cells. Probing into the relationship between the external quantum efficiency derivative (dEQE/dλ) and device performances revealed the Voc-deficit characteristics in the ACZTSSe solar cells as a function of Cu and Ag contents. The fabricated champion ACZTSSe solar cell device showed an efficiency of 12.07% and a record low Voc-deficit of 561 mV. Thorough investigations into the mechanism underpinning the improved performance in the ACZTSSe device further revealed the improved band-tailing characteristic, effective minority carrier lifetime, and diode factors as well as reduced antisite defects and related defect clusters as compared to the CZTSSe device. This study demonstrates the feasibility of effectively suppressing antisite defects, related defect clusters, and band-tailing characteristics by simply introducing a thin Ag layer on a metallic precursor in the kesterite solar cells, which in turn effectively reduces the Voc-deficit.

Diffuse-Type Tenosynovial Giant Cell Tumor of the Tendon Sheath in Both Wrists.

Diffuse-type tenosynovial giant cell tumor (D-TSGCT), previously known as pigmented villonodular synovitis, is a locally aggressive neoplasm that may arise from the synovium, bursa, or tendon sheath. D-TSGCT is usually monoarticular and can be classified into intra- and extra-articular forms, the latter of which is rarer. Here, we report a case of D-TSGCT in a 64-year-old female that involved the entire flexor and extensor tendon sheaths of both wrists. We describe the ultrasonography and MRI findings, as well as review the relevant literature.

Mediastinal Lymph Node Metastasis from Head and Neck Cancer: Predictive Factors and Imaging Features.

Purpose: To assess the predictive factors and describe the imaging features of mediastinal lymph node (MLN) metastases in patients with head and neck cancer. Materials and Methods: We compared the clinical features and disease characteristics (sex, age, site of primary tumor, histologic type, history of prior treatments, TNM stages, and metastasis in cervical LNs) of patients with head and neck cancers between the MLN metastasis and no MLN metastasis groups. We also evaluated the chest CT (distribution and maximum dimension of the largest LN) and PET/CT (maximum standardized uptake value) features of MLN metastases based on the MLN classification. Results: Of the 470 patients with head and neck cancer, 55 (11.7%) had MLN metastasis, involving 150 mediastinal stations. Hypopharynx cancer, recurrent tumor, T4 stage, N2/N3 stages, and M1 stage were found to be significant predicting factors for MLN metastasis. The most common location of MLN metastasis was ipsilateral station 2 (upper paratracheal LNs, 36.4%), followed by ipsilateral station 11 (interlobar LNs, 27.3%) and ipsilateral station 10 (hilar LNs, 25.5%). Conclusion: Metastasis to MLNs should be considered in patients with head and neck cancer, especially in cases that are associated with a hypopharyngeal cancer, recurrent tumor, and high TNM stages.

Determination of optimum pixel size and slice thickness for tractography and ulnar nerve diffusion tensor imaging at the cubital tunnel using 3T MRI.

BACKGROUND: Small peripheral nerve tractography is challenging because of the trade-off among resolution, image acquisition time, and signal-to-noise ratio. PURPOSE: To optimize pixel size and slice thickness parameters for fiber tractography and diffusion tensor imaging (DTI) of the ulnar nerve at the cubital tunnel using 3T magnetic resonance imaging (MRI). MATERIAL AND METHODS: Fifteen healthy volunteers (mean age 30 ± 6.8 years) were recruited prospectively. Axial T2-weighted and DTI scans were acquired, covering the cubital tunnel, using different pixel sizes and slice thicknesses. Three-dimensional (3D) nerve tractography was evaluated for the median number and length of the reconstructed fiber tracts and visual score from 0 to 5. Two-dimensional (2D) cross-sectional DTI was evaluated for fractional anisotropy (FA) values throughout the length of the ulnar nerve. RESULTS: A pixel size of 1.3 mm2 revealed the highest number of reconstructed nerve fibers compared to that of 1.1 mm2 (P = 0.048), with a good visual score. A slice thickness of 4 mm had the highest number of reconstructed nerve fibers and visual score compared with other thicknesses (all P < 0.05). In 2D cross-sectional images, the median FA values were in the range of 0.40-0.63 at the proximal, central, and distal portions of the cubital tunnel. Inter-observer agreement for all parameters was good to excellent. CONCLUSION: For fiber tractography and DTI of the ulnar nerve at the cubital tunnel, optimal image quality was obtained using a 1.3-mm2 pixel size and 4-mm slice thickness under MR parameters of this study at 3T.

First meeting in Asia of the Asia Pacific Research Integrity network.

In 2017, the University of Hong Kong and the University of California San Diego co-hosted the first Asian meeting of the recently formed Asia Pacific Research Integrity (APRI) network in Hong Kong. Aligned with planning meetings in 2015 and 2016 funded in part by the US Office of Research Integrity (ORI), the Hong Kong meeting was designed by a multi-national planning committee to address pressing challenges in research integrity: improving multi-national communication; exchanging information on managing misconduct investigations; and sharing best practices to promote research integrity. To create a sustainable, robust international partnership to promote research integrity in the region, the purpose of this 2017 meeting was to foster multi-national awareness, understanding, and opportunities for collaboration. The meeting was defined by four objectives that emerged from the previous meetings: (1) Articulate differences as well as areas of common ground; (2) Identify best or recommended practices; (3) Identify opportunities for research or collaboration; and (4) Set an APRI network agenda for coming years. The key anticipated outcome was to advance the conversation surrounding research integrity among academic institutions and regulators in Asian and Pacific Rim nations. This outcome was evidenced by meeting participation, participant satisfaction, and articulation of next steps for the APRI network.

Trifunctional layered electrodeposited nickel iron hydroxide electrocatalyst with enhanced performance towards the oxidation of water, urea and hydrazine.

In recent years, low-cost, non-noble metal-based and stable catalysts have gained attention for the development of clean energy devices. Additionally, the synthesis of materials that can exhibit more than one electrocatalytic reaction is notable. In this work, stepwise electrodeposited nickel-iron hydroxide nanoarrays are investigated as anode electrocatalysts with enhanced performance towards the oxidation of water, urea, and hydrazine. The stepwise electrodeposited nickel-iron hydroxide (NiFe(OH)2-SD/NF) electrodes show excellent electrocatalytic activity and stability for the oxygen evolution reaction (OER) with a low potential of 1.45 V (vs RHE) at a current density of 10 mA cm-2. These electrodes further display excellent catalytic activity towards the urea oxidation reaction (UOR) and hydrazine oxidation reaction (HzOR) with potentials lower than 1.32 V (vs RHE) and 0.06 V (vs RHE), respectively. Owing to synergistic effects, a porous structure for mass transport leads to excellent electrocatalytic performance. This non-precious-metal nickel-iron hydroxide, prepared by a simple synthesis approach, is promising for hybrid water electrolysis applications and the development of environmentally friendly clean energy reactions.

Analysis of factors affecting re-admission after retrograde intrarenal surgery for renal stone.

PURPOSE: To investigate the factors associated with hospital readmission (HR) after retrograde intrarenal surgery (RIRS) among renal stone patients. METHODS: The study included patients who underwent RIRS from June 2011 to December 2017. Patients who were readmitted due to surgery-related complications were evaluated retrospectively. Patient demographics including age, medical comorbidity, body mass indices, ASA score, perioperative parameters and stone factors were compared with total cohorts. HR was defined as visits to the Emergency Room or unplanned admission within 30 days after discharge. The factors affecting HR rates were analyzed using uni- and multi-variate analyses. RESULTS: A total of 572 patients were enrolled into the study. The mean age was 57.6 ± 14.1 years and the mean stone diameter was 13.4 ± 6.2 mm. The mean complication rate was 6.1% and the median hospitalization time was 2.1 ± 3.4 days. HR occurred in 20 patients (3.5%). Compared to non-admission patients, readmitted patients had a higher rate of bilateral RIRS (20.0% vs 12.2%, p = 0.035), number of stones (4.65 vs 2.2, p = 0.041) and higher stone complexity score (4.15 vs 2.11, p = 0.003). Multivariate analysis showed bilateral RIRS (OR 1.091, p = 0.031) and stone complexity (OR 1.405, p = 0.003) were significant factors to predict re-admission after RIRS. CONCLUSION: Patients with complex renal stones or those who underwent bilateral RIRS were more likely to have a higher rate of re-admission. Proper perioperative management to prevent complications should be planned based on these predictive factors.

The effect of short-term preoperative ureteral stenting on the outcomes of retrograde intrarenal surgery for renal stones.

OBJECTIVES: To evaluate the effect of preoperative ureteral stenting duration on the outcomes of retrograde intrarenal surgery (RIRS). PATIENTS AND METHODS: We reviewed our database of patients who underwent RIRS between May 2011 and April 2017 at our institution. The patients were divided into three groups according to preoperative ureteral stenting duration: group 1: no stenting, group 2: short preoperative stenting (< 7 days) and group 3: long preoperative stenting (≥ 7 days). We compared the rate of ureteral injury, other perioperative complications, ureteral dilation and readmission, stone-free rate (SFR) and operative time among the groups. RESULTS: A total of 560 patients (215 in group 1, 177 in group 2 and 168 in group 3) were included in this study. The mean of maximum stone size was 13.1 (± 6.2) mm, the mean number of stones was 2.3 (± 1.9) and preoperative ureteral stenting duration was 7.2 (± 3.7) days. There were no significant differences in operative time (75.6, 78.5 and 82.4 min, p = 0.280), SFR (79.1, 84.2 and 81.0%, p = 0.433), ureteral injury rate (7.0, 5.1 and 2.4%, p = 0.123) and other perioperative complication rates (12.1, 6.8 and 6.0%, p = 0.061). The only one case of grade IV ureteral injury occurred in group 1 and the rate of ureteral dilation was significantly higher than in group 2 and 3 (14.9, 5.7 and 6.0%, p < 0.001). CONCLUSION: Although preoperative ureteral stenting duration has no significant effect on operative outcomes, it is an effective procedure for reducing the rate of intraoperative ureteral balloon dilation and preventing high-grade ureteral injuries.

Genetic risk score to predict biochemical recurrence after radical prostatectomy in prostate cancer: prospective cohort study.

PURPOSE: To investigate the genetic risk score (GRS) from a large-scale exome-wide association study as a tool of prediction for biochemical recurrence (BCR) after radical prostatectomy (RP) in prostate cancer (PCa). RESULTS: The 16 SNPs were selected as significant predictors of BCR. The GRS in men experiencing BCR was -1.21, significantly higher than in non-BCR patients (-2.43) (p < 0.001). The 10-year BCR-free survival rate was 46.3% vs. 81.8% in the high-versus low GRS group, respectively (p < 0.001). The GRS was a significant factor after adjusting for other variables in Cox proportional hazard models (HR:1.630, p < 0.001). The predictive ability of the multivariate model without GRS was 84.4%, increased significantly to 88.0% when GRS was included (p = 0.0026). MATERIALS AND METHODS: Total 912 PCa patients were enrolled who had received RP and genotype analysis using Exome chip (HumanExome BeadChip). Genetic results were obtained by the methods of logistic regression analysis which measured the odds ratio (OR) to BCR. The GRS was calculated by the sum of each weighted-risk allele count multiplied by the natural logarithm of the respective ORs. Survival analyses were performed using the GRS. We compared the accuracy of separate multivariate models incorporating clinicopathological factors that either included or excluded the GRS. CONCLUSIONS: GRS had additional predictive gain of BCR after RP in PCa. The addition of personally calculated GRS significantly increased the BCR prediction rate. After validation of these results, GRS of BCR could be potential biomarker to predict clinical outcomes.

Favorable Gleason 3 + 4 Prostate Cancer Shows Comparable Outcomes With Gleason 3 + 3 Prostate Cancer: Implications for the Expansion of Selection Criteria for Active Surveillance.

BACKGROUND: To investigate the feasibility of active surveillance (AS) in biopsy Gleason score (GS) 3 + 4 prostate cancer (PCa), we compared the outcomes of biopsy GS 3 + 3 and 3 + 4 PCa after radical prostatectomy. PATIENTS AND METHODS: We analyzed the data of 1491 patients undergoing radical prostatectomy for biopsy GS 3 + 3 or 3 + 4 PCa who fulfilled the low-risk criteria of the National Comprehensive Cancer Network guidelines regardless of GS. The favorable GS 3 + 4 group was defined as having core involvement ≤ 50%, prostate-specific antigen density ≤ 0.2 ng/mL/cm3, and number of positive cores ≤ 2 (maximal 1 core of GS 3 + 4). RESULTS: The GS 3 + 4 group showed significantly worse pathologic outcomes, including pathologic GS, pathologic stage, and seminal vesicle invasion rate (all P < .001), as well as worse biochemical recurrence-free survival (P < .001) than the GS 3 + 3 group. However, the favorable GS 3 + 4 subgroup showed no significant differences in the pathologic outcomes (all P > .05) and in biochemical recurrence-free survival (P = .817) compared to the GS 3 + 3 group. CONCLUSION: Despite the application of low-risk criteria, GS 3 + 4 PCa patients showed significantly worse outcomes than GS 3 + 3 patients. However, favorable GS 3 + 4 patients showed comparable clinicopathologic outcomes with GS 3 + 3 patients, suggesting possible expansion of AS for the favorable GS 3 + 4 group.