Japanese Journal of Radiology最新文献

Purpose: To assess therapeutic response in patients with neuroendocrine tumors (NETs) using quantitative post-therapy ¹⁷⁷Lu-DOTATATE SPECT/CT metrics, such as standardized uptake values (SUVs), metabolic tumor volume (MTV), and total Lutetium uptake (TLuU), and to propose a response classification system based on these indices.

Materials and methods: In this retrospective study, we analyzed 31 lesions in 7 patients with NETs treated with four cycles of peptide receptor radionuclide therapy (PRRT) with ¹⁷⁷Lu-DOTATATE. Visual interpretation with the Krenning score (K-S) and quantitative analysis (SUVmax, SUVpeak, SUVmean, MTV, TLuU) were performed after each cycle. Volumes of interest (VOI) were segmented using two thresholds: 40% of SUVmax or a fixed cutoff of 2.4. Treatment response was expressed as response ratios (RRs) across PRRT sessions.

Results: SUVmax and SUVpeak correlated strongly with K-S and were consistent across thresholding methods. MTV and TLuU varied by VOI definition, but the cutoff method produced more stable longitudinal assessments. Lesions with early SUV-based RR reductions at the second PRRT cycle showed continued decline across treatment. Patients were categorized as "Good Responder," "Responder," or "Non-responder" based on quantitative trends, which aligned with visual assessments and CT findings.

Conclusion: Quantitative post-PRRT SPECT/CT provides objective, reproducible metrics for assessing NET therapy response. A fixed SUV cutoff allows standardized volumetric assessment. Early SUV-based index declines may act as predictive biomarkers of treatment efficacy, supporting personalized theranostic strategies.

Purpose: Carbon-ion radiotherapy (CIRT) offers high-dose concentration and enhanced biological effects. Since 2016, a nationwide prospective registry study of CIRT for locally advanced non-small cell lung cancer (LA-NSCLC) has been conducted in Japan. This study aimed to evaluate clinical outcomes of CIRT in patients with LA-NSCLC who were ineligible for surgery or chemoradiotherapy (CCRT).

Materials and methods: Patients with inoperable LA-NSCLC treated with CIRT in Japan from May 2016 to June 2020 were included. Most patients received 64-72 Gy in 16 fractions per the Japanese Society for Radiation Oncology (JASTRO) unified policy. Elective nodal irradiation was allowed for nodal disease. No systemic therapy was administered before or after CIRT. Overall and progression-free survival were estimated by the Kaplan-Meier method; local failure was evaluated using the cumulative incidence function (CIF) with Gray's test. Two-sided P < 0.05 was considered significant.

Results: Median follow-up was 28 months for all patients and 36 months for survivors. Of the 55 patients, clinical stages (UICC 8th) were: IIB (26), IIIA (17), and IIIB (12). A clinical diagnosis without histological confirmation was established in four patients (7.3%), and interstitial pneumonia (IP) was present in nine (16.4%). The 3-year overall survival and progression-free survival were 49.1% (95% confidence interval [CI], 33.8-62.7%) and 28.3% (95% CI, 16.6-41.3%), respectively. Using competing risks, the 3-year CIF was 37.4% (95% CI, 24.2-50.5%). No grade ≥ 4 toxicity was observed; grade 2 and 3 pneumonitis occurred in 3 (5.5%) and 2 (3.6%) patients, respectively. In multivariable analysis, concomitant IP was a significant factor for overall survival (P = 0.011).

Conclusion: CIRT demonstrated favorable tumor control with acceptable toxicity in patients with LA-NSCLC ineligible for surgery or CCRT. It may be a promising treatment option for this patient population.

Purpose: To assess the feasibility, safety, and clinical outcomes of salvage reirradiation, using intensity-modulated radiotherapy (IMRT) with a total dose of 30 Gy and cumulative equivalent dose in 2 Gy fractions (EQD2) limited to ≤ 96 Gy in patients with recurrent high-grade gliomas.

Materials and methods: This retrospective study included 24 patients with recurrent high-grade gliomas who underwent IMRT-based reirradiation between 2014 and 2021. Treatment planning was performed using computed tomography-magnetic resonance imaging fusion images, and radiotherapy was delivered via IMRT or volumetric-modulated arc therapy. No concurrent chemotherapy was administered, and the cumulative EQD2 to the brain was restricted to 96 Gy.

Results: The median follow-up was 8 months (range, 1-31 months). The median overall survival was 8 months, with 1- and 2-year overall survival rates of 29% and 4%, respectively. No grade ≥ 2 toxicity or cases of radiation necrosis were observed. All patients completed the planned treatment course without interruption.

Conclusion: Salvage reirradiation using IMRT with an EQD2 limited to ≤ 96 Gy was a feasible and well-tolerated treatment strategy for select patients with recurrent high-grade gliomas. This approach may offer a modest survival benefit with minimal toxicity and warrants further investigation in prospective trials.

Background: This study aimed to investigate the usefulness of time-dependent diffusion magnetic resonance imaging (MRI) parameters compared with the conventional apparent diffusion coefficient (ADC) in distinguishing tumor grade and isocitrate dehydrogenase (IDH) genotypes of adult-type diffuse gliomas.

Methods: This retrospective study included 102 patients with adult-type diffuse gliomas. ADC maps obtained using diffusion-weighted imaging at short (7.1 ms) and long (44.5 ms) diffusion times (ADC7.1ms and ADC44.5ms) and maps of ADC changes (cADC) and relative ADC changes (rcADC) between the two diffusion times were generated. The mean, 5th, and 95th percentile values of each parameter were compared between low-grade (LGGs) and high-grade gliomas (HGGs) and between IDH-mutant and IDH-wildtype gliomas. The discriminative performance was assessed using receiver operating characteristic (ROC) analysis, and correlation with Ki-67 labeling index (Ki-67LI) was assessed using Spearman's rank correlation. Multivariable logistic regression analyses were conducted to predict HGGs and IDH-wildtype gliomas.

Results: In HGGs, the mean and 5th percentile values of ADC44.5ms and ADC7.1ms were significantly lower, whereas cADC and rcADC indices were significantly higher than those in LGGs. Performance of the mean rcADC (area under the ROC curve: 0.925; 95% confidence interval: 0.855-0.967) was significantly better than any index of conventional ADCs for tumor grade classification. The mean rcADC demonstrated the strongest correlation with Ki-67LI (ρ = 0.542, p < 0.0001). Moreover, the 95th percentile of rcADC was an independent predictor of IDH-wildtype gliomas after adjustment for age and sex, was useful for distinguishing IDH-wildtype from IDH-mutant gliomas CONCLUSIONS: The mean rcADC showed the strongest correlation with the Ki-67 LI and achieved better diagnostic performance than conventional PGSE-based ADC for differentiating LGGs from HGGs. In multivariable analyses, the mean and 95th percentile of rcADC were identified as independent predictors of HGGs and IDH-wildtype gliomas, respectively.

Purpose: To characterize the magnetic resonance imaging (MRI) features of Bacillus Calmette-Guérin (BCG)-induced granulomatous prostatitis (GP) and to identify key imaging findings for differentiating it from prostate carcinoma (PCa).

Materials and methods: This retrospective study included 11 patients with pathologically confirmed BCG-induced GP and a comparison group of 88 patients (90 lesions) with PCa. Two radiologists retrospectively evaluated MRI findings. Qualitative analysis included lesion location, morphology, and signal intensity (SI) patterns on T1-weighted (T1WI), T2-weighted (T2WI), and diffusion-weighted imaging (DWI). Quantitative analysis compared lesion size, apparent diffusion coefficient (ADC) values, and T1WI SI ratios to both muscle and background prostate. Statistical comparisons were made using Fisher's exact test for qualitative data and the Mann-Whitney U test for quantitative data.

Results: Hyperintensity on T1WI was significantly more frequent in GP (100%) than in PCa (11%; p < 0.001). The lesion-muscle SI ratio on T1WI was also significantly higher in GP (p < 0.001), whereas the lesion-background SI ratio was not (p = 0.054). Furthermore, a diffuse morphology was significantly more common in GP (45%) compared to PCa (12%; p = 0.014), and the distribution of lesion locations also differed significantly (p = 0.041). No significant differences were found in lesion size, SI on T2WI or DWI and ADC values.

Conclusion: Some PCa exhibit similar imaging findings to GP, but T1 hyperintensity and a diffuse morphology are characteristic features of GP.

Purpose: This systematic review aims to examine the literature of artificial intelligence (AI) algorithms in the diagnosis of hepatocellular carcinoma (HCC) among focal liver lesions compared to radiologists on multiphase CT images, focusing on performance metrics that include sensitivity and specificity as a minimum.

Methods: We searched Embase, PubMed and Web of Science for studies published from January 2018 to May 2024. Eligible studies evaluated AI algorithms for diagnosing HCC using multiphase CT, with radiologist interpretation as a comparator. The performance of AI models and radiologists was recorded using sensitivity and specificity from each study. TRIPOD + AI was used for quality appraisal and PROBAST was used to assess the risk of bias.

Results: Seven studies out of the 3532 reviewed were included in the review. All seven studies analysed the performance of AI models and radiologists. Two studies additionally assessed performance with and without supplementary clinical information to assist the AI model in diagnosis. Three studies additionally evaluated the performance of radiologists with assistance of the AI algorithm in diagnosis. The AI algorithms demonstrated a sensitivity ranging from 63.0 to 98.6% and a specificity of 82.0-98.6%. In comparison, junior radiologists (with less than 10 years of experience) exhibited a sensitivity of 41.2-92.0% and a specificity of 72.2-100%, while senior radiologists (with more than 10 years of experience) achieved a sensitivity between 63.9% and 93.7% and a specificity ranging from 71.9 to 99.9%.

Conclusion: AI algorithms demonstrate adequate performance in the diagnosis of HCC from focal liver lesions on multiphase CT images. Across geographic settings, AI could help streamline workflows and improve access to timely diagnosis. However, thoughtful implementation strategies are still needed to mitigate bias and overreliance.

Purpose: The objective of this study was to explore the relationship between a quantitative CT analysis and the expression of programmed death-ligand 1 (PD-L1) in lung adenocarcinoma.

Materials and methods: This study included 116 patients diagnosed with lung adenocarcinoma who were assessed for the expression of PD-L1. Tumors were classified as pure ground-glass nodules (GGNs), part-solid nodules, and solid nodules. The quantitative CT analysis included the tumor diameter and volume, solid component diameter and volume, and rate of the solid components. The CT criteria, and PD-L1 expression rates were compared based on the tumor proportion score (TPS). Optimal cutoff values were obtained utilizing the maximized Youden index method based on the receiver operating characteristic (ROC) analysis. Univariate and multiple linear regression analyses were also performed to examine the influencing factors of 50% and 1% PD-L1 expression.

Results: Solid nodules were significantly more frequent in the TPS ≥ 50% group (TPS ≥ 50% = 81.8% vs. TPS < 1% = 10.0%). The rate of solid component diameter and rate of solid component volume were significantly smaller in TPS < 1% than in TPS < 50% and 1-49% (p < 0.001, respectively). Multiple linear regression analysis identified the rate of solid component volume as a significant factor influencing 50% and 1% PD-L1 expression (p < 0.001 and p = 0.048, respectively).

Conclusion: High PD-L1 expression rates may be associated with higher rates of solid components in lung adenocarcinoma.