This study aims to evaluate the diagnostic performance of a commercial, fully-automated, artificial intelligence (AI) driven software tool in identifying and grading prostate lesions in prostate MRI, using histopathological findings as the reference standard, while contextualizing its performance within the framework of PI-RADS v2.1 criteria. This retrospective study analyzed 123 patients who underwent multiparametric prostate MRI followed by systematic and targeted biopsies. MRI protocols adhered to international guidelines and included T2-weighted, diffusion-weighted, T1-weighted, and dynamic contrast-enhanced imaging. The AI software tool mdprostate was integrated into the Picture Archiving and Communication System to automatically segment the prostate, calculate prostate volume, and classify lesions according to PI-RADS scores using biparametric T2-weighted and diffusion-weighted imaging. Histopathological analysis of biopsy cores served as the reference standard. Diagnostic performance metrics including sensitivity, specificity, positive and negative predictive value (PPV, NPV), and area under the ROC curve (AUC) were calculated. mdprostate demonstrated 100 % sensitivity at a PI-RADS ≥ 2 cutoff, effectively ruling out both clinically significant and non-significant prostate cancers for lesions remaining below this threshold. For detecting clinically significant prostate cancer (csPCa) using a PI-RADS ≥ 4 cutoff, mdprostate achieved a sensitivity of 85.5 % and a specificity of 63.2 %. The AUC for detecting cancers of any grade was 0.803. The performance metrics of mdprostate were comparable to those reported in two meta-analyses of PI-RADS v2.1, with no significant differences in sensitivity and specificity (p > 0.05). The evaluated AI tool demonstrated high diagnostic performance in identifying and grading prostate lesions, with results comparable to those reported in meta-analyses of expert readers using PI-RADS v2.1. Its ability to standardize evaluations and potentially reduce variability underscores its potential as a valuable adjunct in the prostate cancer diagnostic pathway. The high accuracy of mdprostate, particularly in ruling out prostate cancers, highlights its clinical utility by reducing workload and enhancing patient outcomes.

Background/Objectives: Neurotensin receptors (NTSRs), members of the G protein-coupled receptor (GPCR) family, have been found to be overexpressed in several types of human cancers, including breast, colon, lung, liver, prostate, and pancreatic cancer. In particular, NTSR1 is overexpressed in at least 75% of pancreatic ductal adenocarcinomas. The aim of the present study was the development and evaluation of new ^99mTc-labeled nonpeptide NTSR1-antagonists for SPECT imaging of NTSR-positive tumors. Methods: Multistep syntheses of NTSR1 antagonist derivatives were performed following our previously described procedure. Two different chelating strategies were applied for ^99mTc radiolabeling to provide the [^99mTc]Tc-HYNIC complex [^99mTc]1 and the [^99mTc]Tc-tricarbonyl complex [^99mTc]2. Receptor binding assays were performed using hNTSR1-expressing CHO cells. Radiochemical yields (RCYs) were determined by radio-HPLC. For [^99mTc]1 and [^99mTc]2, log D_7.4, plasma protein binding, stability in human plasma and serum, and cellular uptake in HT-29 cells were determined. Biodistribution studies and small animal SPECT studies were performed in HT-29 tumor-bearing nude mice. Results: The radiosynthesis of [^99mTc]1 (log D_7.4 = −0.27) and [^99mTc]2 (log D_7.4 = 1.00) was successfully performed with RCYs of 94–96% (decay-corrected). Both radioligands were stable in human serum and plasma, showed plasma protein binding of 72% ([^99mTc]1) and 82% ([^99mTc]2), and exhibited high and specific uptake in HT-29 cells. Biodistribution studies in HT-29 tumor-bearing mice showed a higher tumor accumulation of [^99mTc]1 compared to [^99mTc]2 (8.8 ± 3.4 %ID/g vs. 2.7 ± 0.2 %ID/g at 2 h p.i.). [^99mTc]2 showed exceptionally high intestinal accumulation (49 ± 22 %ID/g at 1 h p.i.) and was therefore considered unfavorable. In the SPECT/CT imaging of HT-29 tumor xenografts, [^99mTc]1 showed a higher NTSR1-specific tumor uptake than [^99mTc]2 at all time points after tracer injection, with 12 ± 2.8 %ID/g for [^99mTc]1 vs. 3.1 ± 1.1 %ID/g for [^99mTc]2 at 4 h p.i. and adequate tumor-to-background ratios. Conclusions: In particular, the [^99mTc]Tc-HYNIC ligand ([^99mTc]1) showed promising preclinical results, being a potential candidate for SPECT imaging and, therefore, appropriate for translation into the clinic.

Coronary CT angiography (CCTA) is recommended as a first-line test for evaluating suspected coronary artery disease in many patient cohorts. Photon-counting detector CT (PCD-CT) introduces direct energy discrimination, higher geometric dose efficiency, and ultrahigh spatial resolution compared to energy-integrating detector CT, enabling improved coronary lumen visualization and intrinsic spectral imaging. This multi-institutional guidance summarizes technical principles of PCD-CT relevant to cardiac imaging and synthesizes contemporary evidence across key applications: (1) CCTA protocol selection and reconstruction (including ultrahigh-resolution modes); (2) stent and heavily calcified plaque assessment; (3) coronary physiology using CT-derived fractional flow reserve; (4) structural heart evaluation including pre-TAVR planning; and (5) myocardial tissue characterization with late enhancement and extracellular volume mapping. We provide pragmatic protocol pathways and contrast-dose strategies, with compact tables that standardize scan modes, reconstruction kernels, iterative reconstruction levels, and spectral outputs.

Background/Objectives: There is an increasing need for cross-sectional imaging in pediatric patients with congenital heart disease. This patient group is highly sensitive to ionizing radiation. The purpose of this article was to evaluate differences in radiation dose and image quality between a first-generation photon-counting (PC)-CT system and a 256-slice single-source energy-integrating detector (EID)-CT in these patients. Methods: We retrospectively assessed effective dose, CT dose index-volume (CTDI_vol), dose length product (DLP), and image quality of all prospectively electrocardiography-gated CTs of the thorax in all patients < 18 years of age examined between February 2021 and August 2024 (n = 43). Two independent observers subjectively scored image quality, vascular contrast, and noise on a 5-point Likert scale. In addition, we assessed the signal-to-noise-ratio (SNR) and contrast-to-noise-ratio (CNR) quantitatively. Results: All dose parameters were significantly lower in the PC-CT (n = 27) versus the EID-CT (n = 16) group (mean effective dose: 0.8 ± 0.64 versus 2.2 ± 0.88 mSv, p < 0.001; mean CTDI_vol: 1.22 ± 0.96 versus 4.8 ± 1.08 mGy, p < 0.001; mean DLP: 30.7 ± 31.9 versus 73.7 ± 50.7 mGy*cm, p < 0.001). Overall subjective image quality and contrast were rated higher in the PC-CT group (p = 0.046 and < 0.001, respectively). Quantitative CNR was significantly higher in the PC-CT group (mean 39.1 ± 12.9 versus 26.2 ± 10.8, p = 0.002). Conclusions: PC-CT enables high-quality examinations for the evaluation of congenital heart disease with a highly significant dose reduction compared with a 256-slice single-source EID-CT.

Background/Objectives: Pediatric patients with solid tumors (non-lymphoma) require adequate staging prior to and during therapy. ¹⁸F-FDG-PET/CT is commonly used for the detection of tumorous lesions, with the drawback of exposure to ionizing radiation. Whole-body MRI (WB-MRI) can be considered as a complementary method according to clinical guidelines. The main objective of this study was to assess the diagnostic performance of the aforementioned methods for the detection of metastases, both separately and in combination. Methods: We retrospectively assessed sensitivity and specificity of ¹⁸F-FDG-PET/CT, WB-MRI, and the combination of both methods for the detection of lymph node and distant metastases in pediatric patients with solid tumors. Results: A total of 21 patients who underwent both ¹⁸F-FDG-PET/CT and WB-MRI were included in this study. We found 109 confirmed metastatic lesions in 1322 body regions. Sensitivity and specificity for the whole collective were 63.4%/99.3% for ¹⁸F-FDG-PET/CT, 91.3%/98.6% for WB-MRI, and 100%/98.2% for the combination of both methods. In 11 therapy-naïve patients, both ¹⁸F-FDG-PET/CT and WB-MRI exhibited a sensitivity of 84.7%, while specificity was 98.8% for ¹⁸F-FDG-PET/CT and 98.5% for WB-MRI. The combination of both methods led to a significant increase in sensitivity to 100% in both therapy-naïve patients and patients under chemotherapy (both p < 0.001), while specificity remained high (97.7%/98.7%). Conclusions: ¹⁸F-FDG-PET/CT in combination with WB-MRI showed a higher sensitivity for the detection of metastases in solid malignant pediatric tumors than either of the methods alone. Thus, the combination allows for the most accurate staging.

Background: Lung surveillance in cystic fibrosis (CF) relies on chest radiography (CR) despite cumulative radiation. Low-field MRI may be a radiation-free alternative for children and young adults. Methods: We prospectively compared 0.55 T MRI and CR in 28 same-day examinations of 22 people with CF (mean age 13 ± 5 years). Three raters scored the disease with the MRI CF score and a modified Chrispin–Norman score, expanded from two to three zones per hemithorax to match the six MRI lobes. Analyses used per-examination values averaged across the raters (Wilcoxon tests, intraclass correlation coefficients, ICC). Results: MRI yielded higher global scores (median 8.2 vs. 6.7, p = 0.002) and higher centrilobular opacity scores (p = 0.005, adjusted p = 0.03). Air trapping was also higher on MRI (p = 0.025) but not after correction for multiple comparisons (adjusted p = 0.12). The other categories did not differ. Both correlated inversely with FEV1 (p < 0.001), without a significant modality-by-FEV1 interaction (p = 0.08). Interobserver agreement was higher for MRI (ICC = 0.93) than CR (0.82), difference 0.12 (95% bootstrap CI 0.06 to 0.18). The findings held in a per-participant sensitivity analysis. Conclusions: 0.55 T MRI is a feasible, radiation-free alternative to CR in CF, yielding higher modality-specific scores and more consistent interobserver agreement. Because the instruments were only category-mapped and no CT reference was available, higher scores do not establish superior lesion detection.