Artificial Intelligence-Guided Segmentation and Path Planning Software for Transthoracic Lung Biopsy.

PURPOSE: To validate the sensitivity and specificity of a 3-dimensional (3D) convolutional neural network (CNN) artificial intelligence (AI) software for lung lesion detection and to establish concordance between AI-generated needle paths and those used in actual biopsy procedures. MATERIALS AND METHODS: This was a retrospective study using computed tomography (CT) scans from 3 hospitals. Inclusion criteria were scans with 1-5 nodules of diameter ≥5 mm; exclusion criteria were poor-quality scans or those with nodules measuring <5mm in diameter. In the lesion detection phase, 2,147 nodules from 219 scans were used to develop and train the deep learning 3D-CNN to detect lesions. The 3D-CNN was validated with 235 scans (354 lesions) for sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) analysis. In the path planning phase, Bayesian optimization was used to propose possible needle trajectories for lesion biopsy while avoiding vital structures. Software-proposed needle trajectories were compared with actual biopsy path trajectories from intraprocedural CT scans in 150 patients, with a match defined as an angular deviation of <5° between the 2 trajectories. RESULTS: The model achieved an overall AUC of 97.4% (95% CI, 96.3%-98.2%) for lesion detection, with mean sensitivity of 93.5% and mean specificity of 93.2%. Among the software-proposed needle trajectories, 85.3% were feasible, with 82% matching actual paths and similar performance between supine and prone/oblique patient orientations (P = .311). The mean angular deviation between matching trajectories was 2.30° (SD ± 1.22); the mean path deviation was 2.94 mm (SD ± 1.60). CONCLUSIONS: Segmentation, lesion detection, and path planning for CT-guided lung biopsy using an AI-guided software showed promising results. Future integration with automated robotic systems may pave the way toward fully automated biopsy procedures.

Continuous monitoring of postirradiation reoxygenation and cycling hypoxia using electron paramagnetic resonance imaging.

Reoxygenation has a significant impact on the tumor response to radiotherapy. With developments in radiotherapy technology, the relevance of the reoxygenation phenomenon in treatment efficacy has been a topic of interest. Evaluating the reoxygenation in the tumor microenvironment throughout the course of radiation therapy is important in developing effective treatment strategies. In the current study, we used electron paramagnetic resonance imaging (EPRI) to directly map and quantify the partial oxygen pressure (pO2 ) in tumor tissues. Human colorectal cancer cell lines, HT29 and HCT116, were used to induce tumor growth in female athymic nude mice. Tumors were irradiated with 3, 10, or 20 Gy using an x-ray irradiator. Prior to each EPRI scan, magnetic resonance imaging (MRI) was performed to obtain T2-weighted anatomical images for reference. The differences in the mean pO2 were determined through two-tailed Student's t-test and one-way analysis of variance. The median pO2 60 min after irradiation was found to be lower in HCT116 than in HT29 (9.1 ± 1.5 vs. 14.0 ± 1.0 mmHg, p = 0.045). There was a tendency for delayed and incomplete recovery of pO2 in the HT29 tumor when a higher dose of irradiation (10 and 20 Gy) was applied. Moreover, there was a dose-dependent increase in the hypoxic areas (pO2  < 10 mmHg) 2 and 24 h after irradiation in all groups. In addition, an area that showed pO2 fluctuation between hypoxia and normoxia (pO2  > 10 mmHg) was also identified surrounding the region with stable hypoxia, and it slightly enlarged after recovery from acute hypoxia. In conclusion, we demonstrated the reoxygenation phenomenon in an in vivo xenograft model study using EPRI. These findings may lead to new knowledge regarding the reoxygenation process and possibilities of a new radiation therapy concept, namely, reoxygenation-based radiation therapy.

Survival Outcome after Reduced-Port Laparoscopic Radical Cystectomy for Bladder Cancer: Long-Term Follow-Up Analysis.

INTRODUCTION: This study had two objectives: (i) to evaluate oncological outcomes in a long-term follow-up of patients with bladder cancer after reduced-port laparoscopic radical cystectomy (RP-LRC) and (ii) to assess the effect of modified Glasgow prognostic scores (mGPS) on patient outcomes. METHODS: Consecutive patients (n = 100) who received RP-LRC between March 2012 and December 2018 at our institution and affiliated hospital were retrospectively reviewed. Preoperative serum albumin and C-reactive protein levels were determined. Patients were grouped based on clinical T stage (≤cT2: n = 75, ≥cT3: n = 25) using pooled cumulative data. Oncological outcomes and mGPS as a prognostic biomarker were analyzed retrospectively. Kaplan-Meier curves displayed recurrence and survival rates. Univariate and multivariate Cox regression analyses evaluated potential prognostic factors for recurrence-free survival (RFS) and cancer-specific survival (CSS). RESULTS: Patient characteristics between the two groups were statistically similar for preoperative hematological and mGPS status, blood loss level, rate of allogeneic transfusion, and pneumoperitoneum time. After a median follow-up period of 55 months, 40/100 patients experienced disease relapse. RFS and CSS for ≤cT2 were significantly less than for ≥cT3 (p < 0.001, p < 0.05, respectively). Distant metastasis occurred in 30 patients with similar distributions of relapse sites between T-stage cohorts. Median RFS for mGPS 1/2 were 18.9 (95% confidence interval [CI]: 8.8-not assessed [NA]) and 35.0 (95% CI: 8.7-NA) months, respectively, significantly worse than for mGPS 0 (median NA, 95% CI: NA-NA); CSS was similar. Univariate and multivariate analyses revealed ≥cT3 stage, worse clinical N stage, and poor mGPS status were significant prognostic factors for short RFS and CSS. CONCLUSIONS: A large proportion of bladder cancer patients who undergo RP-LRC experience relapse, with ≥cT3 stage, worse clinical N stage or poor mGPS status identified as significant prognostic factors. Our findings may contribute to improved surgical procedures for such patients.

Daily irradiation versus irradiation at two- to three-day intervals in stereotactic radiotherapy for patients with 1-5 brain metastases: study protocol for a multicenter open-label randomized phase II trial.

BACKGROUND: Radiobiological daily changes within tumors are considered to be quite different between stereotactic radiotherapy (SRT) (e.g., 50 Gy in 4 fractions) and conventional radiotherapy (e.g., 60 Gy in 30 fractions). We aim to assess the optimal interval of irradiation in SRT and compare outcomes of daily irradiation with irradiation at two- to three-day intervals in SRT for patients with one to five brain metastases (BM). METHODS: This study is conducted as a multicenter open-label randomized phase II trial. Patients aged 20 or older with one to five BM, less than 3.0 cm diameter, and Karnofsky Performance Status ≥70 are eligible. A total of 70 eligible patients will be enrolled. After stratifying by the number of BMs (1, 2 vs. 3-5) and diameter of the largest tumor (< 2 cm vs. ≥ 2 cm), we randomly assigned patients (1:1) to receive daily irradiation (Arm 1), or irradiation at two- to three-day intervals (Arm 2). Both arms are performed with total dose of 27-30 Gy in 3 fractions. The primary endpoint is an intracranial local control rate, defined as intracranial local control at initially treated sites. We use a randomized phase II screening design with a two-sided α of 0∙20. The phase II trial is positive with p < 0.20. All analyses are intention to treat. This study is registered with the UMIN-clinical trials registry, number UMIN000048728. DISCUSSION: This study will provide an assessment of the impact of SRT interval on local control, survival, and toxicity for patients with 1-5 BM. The trial is ongoing and is recruiting now. TRIAL REGISTRATION: UMIN000048728. Date of registration: August 23, 2022. https://center6.umin.ac.jp/cgi-bin/ctr/ctr_view_reg.cgi?recptno=R000055515 .

Carbon Dioxide Angiography for the Detection of Lower Gastrointestinal Arterial Bleeding Initially Occult to Angiography with Iodinated Contrast Media.

This study evaluated the utility of carbon dioxide (CO2) in angiography for the detection of lower gastrointestinal arterial bleeding initially occult to angiography with iodinated contrast media. Fourteen patients underwent CO2-enhanced angiography. In all patients, extravasation was identified by contrast-enhanced computed tomography but not by initial iodinated contrast-enhanced angiography. After iodinated contrast-enhanced angiography, CO2-enhanced angiography was performed from the same catheter position. The detection capability for extravasation on CO2-enhanced angiography was evaluated. CO2-enhanced angiography allowed for the visualization of extravasation and subsequent transcatheter arterial embolization in 11 of 14 (79%) cases, with extravasation seen during either CO2-enhanced angiography (n = 8) or subsequent repeat iodinated contrast-enhanced angiography immediately after negative CO2-enhanced angiography (n = 3). Conservative treatment was performed in the remaining 3 cases. In conclusion, CO2-enhanced angiography appears useful for identifying occult lower gastrointestinal bleeding.

Utilization of an Occlusion Balloon Catheter during Stent-Graft Placement to Treat Postsurgical Visceral Arterial Hemorrhage.

The utility of occluding the bleeding artery using an occlusion balloon catheter during stent-graft placement for visceral artery bleeding was evaluated. Stent-graft placement for visceral artery bleeding was performed using a balloon catheter in 6 patients. All bleeding occurred after biliary or pancreatic surgery. Since 1 patient underwent the procedure twice, 7 procedures were assessed in total. Technical success, procedure-related adverse events, and 30-day mortality rates were evaluated. Technical success was defined as the placement of the stent-graft at the target site and the resolution of extravasation or pseudoaneurysm. In all procedures, stent-graft placement was successfully performed (technical success rate, 100%). Focal liver infarction occurred in 2 of 7 patients (29%), but did not require further treatment and was considered a minor adverse event. The 30-day mortality rate was 0%. In conclusion, the use of an occlusion balloon in the feeding artery facilitated successful stent-graft repair of hemorrhage from visceral arteries.

Detection of metabolic change in glioblastoma cells after radiotherapy using hyperpolarized 13 C-MRI.

Dynamic nuclear polarization (DNP) of 13 C-labeled substrates enables the use of magnetic resonance imaging (MRI) to monitor specific enzymatic reactions in tumors and offers an opportunity to investigate these differences. In this study, DNP-MRI chemical shift imaging with hyperpolarized [1-13 C] pyruvate was conducted to evaluate the metabolic change in glycolytic profiles after radiation of two glioma stem-like cell-derived gliomas (GBMJ1 and NSC11) and an adherent human glioblastoma cell line (U251) in an orthotopic xenograft mouse model. The DNP-MRI showed an increase in Lac/Pyr at 6 and 16 h after irradiation (18% ± 4% and 14% ± 3%, respectively; mean ± SEM) compared with unirradiated controls in GBMJ1 tumors, whereas no significant change was observed in U251 and NSC11 tumors. Metabolomic analysis likewise showed a significant increase in lactate in GBMJ1 tumors at 16 h. An immunoblot assay showed upregulation of lactate dehydrogenase-A expression in GBMJ1 following radiation exposure, consistent with DNP-MRI and metabolomic analysis. In conclusion, our preclinical study demonstrates that the DNP-MRI technique has the potential to be a powerful diagnostic method with which to evaluate GBM tumor metabolism before and after radiation in the clinical setting.

Time-resolved magnetic resonance angiography as a follow-up method for visceral artery aneurysm treated with coil-embolisation.

PURPOSE: The purpose of this study is to assess the feasibility and usefulness of time-resolved magnetic resonance angiography (TR-MRA) for follow-up of visceral artery aneurysms (VAAs) after embolotherapy. MATERIAL AND METHODS: Twenty-one VAAs (11 splenic, six renal, three internal iliac, and one superior pancreaticoduodenal artery aneurysms) in 18 patients (median age, 64 years; range, 36-88 years) previously treated by embolisation with platinum coils, were evaluated. The mean size of the aneurysm was 10.5 cm3 (range, 0.3-132 cm3). Among them, 19 lesions were treated by aneurysmal packing with or without distal-to-proximal embolisation. For the remaining two lesions, distal-to-proximal embolization alone was performed. The mean observation period after embolotherapy was 35 weeks (range, 4-216). All patients underwent TR-MRA following an intravenous bolus injection of gadolinium chelate. Recanalisation was diagnosed when any portion of the aneurysmal sac was enhanced in the arterial phase. RESULTS: On TR-MRA, two lesions were diagnosed as recanalised. They were confirmed by transcatheter arteriography and re-treated by embolotherapy. For the remaining 19 lesions, there were no findings of recanalisation on TR-MRA. CONCLUSIONS: TR-MRA appears to be a feasible method for follow-up examination of VAAs treated by embolotherapy.

Quality Improvement of Dual-Energy Lung Perfusion Image by Reduction of Low-Energy X-Ray Spectrum: An Evaluation on Clinical Images.

BACKGROUND: The effects of the reduction of low-energy X-ray spectrum on lung perfusion images created by dual-energy CT have not been well evaluated. The aim of this study is to investigate the reliability of lung perfusion blood volume (PBV) images created by dual-energy CT (DECT) equipped with or without a tin filter, focusing on its accuracy adjacent to high-attenuation areas. MATERIAL/METHODS: Among 176 patients who underwent DECT for suspicion of pulmonary embolism, 38 patients (mean age, 64; range, 16 to 83 years) without apparent evidence of pulmonary embolism were evaluated in this study. They underwent DECT at 100/140 kVp with a tin filter on 140 kVp tube (Group A; n=18) or at 80/140 kVp without the filter (Group B; n=20). On the lung PBV images, the degrees of artifacts - pulmonary enhancement defect (PED) and pseudo-enhancement in the trachea (PTE) adjacent to the vena cava were evaluated using a four-point scale (0=minimal to 3=prominent). RESULTS: The mean degrees of artifact in Group A were significantly lower than those in Group B (0.8 vs. 1.9; P<0.0001 for PED, respectively, and 1.1 vs. 2.2; P<0.0001 for TPE, respectively). The mean CTDIvols were 4.90±1.14 and 12.98±3.15 mGy (P<0.0001) for Group A and Group B, respectively. CONCLUSIONS: The quality and accuracy of dual-energy lung perfusion image will be improved by using the tin filter technique.