OBJECTIVE:The aim of the study was to evaluate the role of 18F-fluorodeoxyglucose (FDG) PET/computed tomography (CT) in monitoring treatment response and determining treatment end points in patients with extraspinal musculoskeletal tuberculosis (MSK-TB) receiving anti-tubercular therapy (ATT). METHODS:In this prospective observational study, 62 patients with extraspinal MSK-TB underwent baseline 18F-FDG PET/CT before ATT, with follow-up scans at 6, 12, and 18 months. Total lesion glycolysis (TLG), maximum standardized uptake value (SUVmax), and lesion-to-liver standardized uptake value ratio (SUVR) were recorded. Clinical, laboratory, and MRI findings were used as reference standards for healing. Receiver operating characteristic analysis identified PET/CT parameters associated with ATT beyond 18 months. RESULTS:Fifty-one patients completed the final PET/CT follow-up. Significant reductions in TLG, SUVmax, and SUVR were observed during treatment (all P < 0.05). ROC analysis demonstrated that a ≤43% reduction in TLG, ≤46% reduction in SUVmax, and ≤26% reduction in SUVR between baseline and 6-month scans, and a ≤66% reduction in TLG, ≤36% reduction in SUVmax, and ≤30% reduction in SUVR between baseline and 12-month scans, were associated with the requirement for ATT beyond 18 months. The mean time to complete clinicoradiological healing was 19.23 ± 1.49 months, whereas the mean time to complete metabolic response on PET/CT was 18.54 ± 2.27 months, with no statistically significant difference (P = 0.30). CONCLUSION:18F-FDG PET/CT is a valuable tool for monitoring treatment response in extraspinal MSK-TB. Early changes in PET/CT parameters may predict treatment duration, and PET/CT findings closely correlate with disease healing, supporting its use in guiding individualized ATT duration.
BACKGROUND:This study aimed to develop a single-photon emission computed tomography/computed tomography (SPECT/CT)-based radiomics model using bone metastases to predict epidermal growth factor receptor (EGFR) mutation status and the efficacy of targeted therapy in patients with non-small-cell lung cancer. METHODS:This retrospective study included 240 patients with non-small-cell lung cancer. Among them, 205 were analyzed for the EGFR-mutation prediction model, and 210 for the targeted therapy efficacy model. Baseline and post-treatment whole-body SPECT/CT bone scans with maximum standardized uptake value (SUVmax) were acquired. Radiomic features from bone-metastasis SPECT/CT images were selected by minimum redundancy maximum relevance and least absolute shrinkage and selection operator regression. Seven machine learning algorithms were assembled to construct predictive models, whose performance was assessed via receiver operating characteristic curves, calibration curves, decision-curve analysis, and SHapley Additive exPlanations for model interpretability. RESULTS:Among the seven machine learning models, the eXtreme Gradient Boosting model was the optimal. For the clinical-radiomics-SUVmax EGFR-mutation model, predictive factors included BMI, nonsmoking status, aspartate aminotransferase, leukocyte counts, erythrocyte counts, and SUVmax; the area under the receiver operating characteristic curve (AUC) values were 0.867 [95% confidence interval (CI): 0.823-0.911, training] and 0.834 (95% CI: 0.757-0.911, validation). For the radiomics-ΔSUVmax efficacy model (ΔSUVmax > -0.18), AUCs reached 0.869 (95% CI: 0.828-0.910, training) and 0.846 (95% CI: 0.769-0.923, validation) (all P < 0.05). CONCLUSION:SPECT/CT-derived bone metastasis radiomics offers complementary information for predicting EGFR mutation and targeted therapy efficacy. Models integrating clinical and metastatic‑lesion features may facilitate individualized treatment decision‑making.
BACKGROUND:Pediatric osteomyelitis is a serious bone infection whose early diagnosis remains challenging because clinical and laboratory findings are often nonspecific. Although Tc-99m methylene diphosphonate (MDP) bone scintigraphy is highly sensitive for detecting osteoblastic activity and multifocal disease, image interpretation remains largely qualitative and subject to interobserver variability. This study evaluated whether radiomics analysis of planar Tc-99m MDP bone scintigraphy could quantitatively differentiate infected from contralateral normal bone in children with suspected osteomyelitis. METHODS:This retrospective single-center study included 28 pediatric patients with suspected osteomyelitis who underwent anterior and posterior planar Tc-99m MDP bone scintigraphy. Paired infected and contralateral normal bone regions of interest (ROIs) of each patient were segmented. A standardized radiomics pipeline extracted 62 quantitative features per ROI, including shape, first-order intensity, and higher-order texture features. Statistical analyses included paired Wilcoxon signed-rank testing, effect size analysis, mutual information assessment, and leave-one-out cross-validated (LOOCV) logistic regression. A compact multivariable radiomics score was subsequently derived from the top-performing features. RESULTS:Texture-based radiomic features showed the strongest discrimination between infected and contralateral bone, with gray-level co-occurrence matrix-derived correlation and information-theoretic metrics - particularly T_InformationCorrelation2Averaged2D, T_InformationCorrelation2SliceMerged2D, and T_CorrelationAveraged2D/T_CorrelationSliceMerged2D - demonstrating highly significant differences (all P < 0.001) and large paired effect sizes (Cohen's d ≈ 0.80-0.85). Single-feature logistic regression models achieved moderate discrimination (LOOCV AUC: 0.60-0.63). CONCLUSION:Planar Tc-99m MDP bone scintigraphy radiomics differentiated infected from normal contralateral bone in pediatric osteomyelitis, with texture-derived features outperforming intensity metrics (all P < 0.001; Cohen's d ≈ 0.80-0.85), supporting radiomics as an objective adjunct to visual interpretation.
PURPOSE:This study investigated the significance of ilioinguinal nodal uptake percentages in the evaluation of lower limb lymphoscintigraphy. METHODS:Lymphoscintigraphy studies from 161 patients were retrospectively evaluated. Region-of-interest counts from the injection sites at baseline and from whole-body images at 120 min were corrected for count duration and radioactive decay; ilioinguinal nodal uptake percentages were then calculated for each lower limb. Nodal uptake percentages were compared between normal and abnormal findings in the corresponding limbs and among the study-specific lymphoscintigraphic classification groups. RESULTS:The median ilioinguinal nodal uptake was 18.6%, with an interquartile range of 11-27, in 127 limbs with a normal lymphoscintigraphic pattern. Uptake values were higher in limbs showing features suggestive of increased lymphatic flow reserve, such as collateral lymphatic channels, but decreased with progressive lymphatic dysfunction (P < 0.001). Uptake values differed significantly among the study-specific lymphoscintigraphic classification groups (P < 0.001). Visual assessments showed a moderate correlation with semiquantitative assessments in determining asymmetry of the ilioinguinal lymph nodes on both sides (Pearson's r = 0.52, P < 0.001). CONCLUSION:Although ilioinguinal nodal uptake percentages are widely distributed, the observed distribution in limbs with normal lymphoscintigraphic patterns and selected threshold values may support visual interpretation.
OBJECTIVE:Nuclear medicine is a well-established modality for assessing infection or loosening of prosthetic joint replacements. However, previous research suggests that loosening and low-grade periprosthetic infection can appear similar. Patients with vitamin D deficiency have been noted to have poorer outcomes postsurgery for both infection and loosening. Patients with low-grade uptake and low vitamin D levels may be mismanaged if imaging is inaccurate. This study evaluated the association between nuclear medicine imaging accuracy and vitamin D levels in patients with prosthetic joint replacements. METHODS:A retrospective single-center cohort study was carried out. Data were collected anonymously with 298 cases including knee and hip prostheses. Clinical findings were split into two categories: matched, whereby scan reports agreed with clinical findings, and unmatched, whereby they did not match and therefore imaging was inaccurate. Chi-squared and Fisher's exact tests were performed to assess statistical significance. RESULTS:Analysis shows a statistically significant association between imaging accuracy of prosthetic joint replacements and vitamin D level (P < 0.001). There was no significant difference between prosthesis types. Patients with low vitamin D were 2.61 times more likely to have inaccurate results. CONCLUSION:There was an association between vitamin D levels and nuclear medicine imaging accuracy, and imaging results in cases with low vitamin D levels were two times more likely to be inaccurate. Prospective research would be appropriate to further confirm this. Vitamin D levels could be used as an indicator for the accuracy of imaging results, or low vitamin D levels could be managed before imaging.
Radiopharmaceutical therapy is one of the treatment modalities used for the palliative management of pain associated with bone metastases. Given that radiopharmaceuticals may cause adverse reactions, this study aims to systematize the findings of published research on the use of strontium-89, samarium-153, rhenium-186, rhenium-188, and lutetium-177 in this clinical context. Adverse reactions were analyzed through a two-part approach. The first section presents a systematic literature review conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement, using the MEDLINE and EBSCO databases, from which 29 articles were selected. Findings indicate that the four radiopharmaceuticals yielded broadly comparable results across pain relief, reduction in analgesic consumption, acute administration-related adverse reactions, hematological toxicity, and disease progression. The second section critically appraises the methodological quality of the included publications, using a structured assessment tool. Results indicate that, although therapeutic radiopharmaceuticals generally demonstrate a favorable safety profile, hematological toxicity, particularly leukopenia and thrombocytopenia, is the most frequently reported adverse reaction. The spontaneous reporting system continues to face significant challenges, including data limitations in vulnerable populations, conflicting causality assessments, and underreporting. In conclusion, the use of radiopharmaceuticals for pain palliation appears to be safe and represents a viable alternative to existing treatments. This work underscores the importance of integrating pharmacovigilance practices specific to radiopharmaceuticals, promoting structured adverse reactions reporting, and enhancing clinical awareness to safeguard patient safety.
BACKGROUND:Respiratory motion artifacts degrade PET/computed tomography (PET/CT) image quality. Data-driven gated (DDG) PET/CT addresses this issue by extracting respiratory signals directly from PET data, eliminating the need for external monitoring devices. This study investigated the effects of data extraction percentage (%count) and deep learning-based reconstruction [Advanced Intelligent Clear-IQ Engine-integrated (AiCE-i)] on image quality in DDG-PET under different respiratory conditions using a phantom model. METHODS:A body phantom containing six spheres (10-37 mm) was imaged using a silicon photomultiplier-based PET/CT system. Four respiratory waveforms (no-motion, sinusoidal, representative patient, and baseline shift) and four %count levels (20, 30, 40, and 50%) were evaluated using AiCE-i reconstruction. Image quality was assessed using background variability (N10 mm), percentage contrast (QH,10 mm), contrast-to-noise ratio (QH,10 mm/N10 mm), and recovery coefficient. RESULTS:Increasing %count consistently reduced N10 mm across all respiratory waveforms. QH,10 mm and QH,10 mm/N10 mm generally increased with increasing %count; however, at the 50% threshold, significant reductions were observed in the baseline shift and sinusoidal waveforms compared with the no-motion condition. Recovery coefficient analysis demonstrated the partial volume effect in smaller spheres and showed that quantitative performance was maintained across the evaluated gating conditions. CONCLUSION:The combination of DDG and AiCE-i maintained stable image quality across the respiratory conditions evaluated. Under the conditions of this phantom study, a %count range of 30-40% provided a favorable balance between image noise and the effects of respiratory motion for standard 120-s acquisitions.
AIM:To explore the correlation between isocitrate dehydrogenase (IDH) mutation status and 18F-deoxyglucose (18F-FDG) PET/computed tomography (CT) metabolic parameters in gliomas, and screen imaging biomarkers for preoperative prediction of IDH genotype. METHODS:Clinical and preoperative PET/CT data of 85 pathologically confirmed glioma patients were retrospectively analyzed, including 34 IDH-mutant and 51 IDH-wild-type cases. Lesion maximum standard uptake value (SUVmax), SUVmax T/C (lesion-to-contralateral cortex) and SUVmax T/W (lesion-to-contralateral white matter) were measured. Intergroup differences were compared via one-way analysis of variance, and receiver operating characteristic curves were applied to assess the predictive efficacy of significant parameters. RESULTS:All three metabolic indices were markedly elevated in IDH-wild-type tumors: SUVmax (11.77 ± 5.94 vs. 9.46 ± 3.30; P = 0.042), SUVmax T/C (1.63 ± 0.67 vs. 1.34 ± 0.40; P = 0.028), SUVmax T/W (2.80 ± 1.19 vs. 2.31 ± 0.63; P = 0.024). SUVmax T/C [area under the curve (AUC) = 0.671] and SUVmax T/W (AUC = 0.668) showed moderate predictive value, whereas SUVmax had poor performance (AUC = 0.339). Patients with IDH mutation were significantly younger. CONCLUSION:IDH-wild-type gliomas present stronger glycolytic metabolism. 18F-FDG PET/CT-derived SUVmax, SUVmax T/C, and SUVmax T/W allow noninvasive preoperative evaluation of IDH status, with normalized ratio parameters demonstrating better diagnostic stability. Higher metabolic heterogeneity exists in IDH-wild-type gliomas.
OBJECTIVES:Recent advances in bone scintigraphy, including multi-head detector systems, improved reconstruction algorithms, and novel detector technologies, offer opportunities to enhance image quality, reduce acquisition times, and lower administered activities. However, it is unclear whether these changes have led to updates in clinical practice or optimisation of local diagnostic reference levels in the UK. METHODS:The UK Heads of Nuclear Medicine Physics group commissioned a national survey to determine whether these developments have led to practical advancements. RESULTS:Fifty-four responses were received: England (36), Scotland (11), Wales (5), and Northern Ireland (2). Of these, 50 sites perform planar bone scans, using predominantly Siemens or General Electric scanners (98%), with Siemens Symbia/Intevo and General Electric 600/800 systems each representing 43% of responses. Substantial variation in protocols was observed. Optimisation of planar imaging was reported by 24% of sites, with aims including reduced scan time, lower administered activity, improved image quality, or combinations thereof. The majority of sites (88%) use fixed administered activities for planar oncology scans, either 500 MBq (11%), 550 MBq (16%), or 600 MBq (73%), rather than weight-based activities. CONCLUSIONS:This study demonstrated that the majority of sites use the Administration of Radioactive Substances Advisory Committee national diagnostic reference levels (NDRLs) for administered activity. Sites that had optimised protocols were more likely to use weight-based administered activities. The majority of respondents (49/50) supported reviewing the current NDRLs, which predate many of the technological developments. This work demonstrates the considerable variation in UK bone scintigraphy practice and suggests further optimisation is achievable.
The aim of this study was to describe Yttrium Radioembolization Dosimetry Evaluation (YRDose), an investigational open-source software suite for image-based activity planning and optional post-therapy dosimetry in yttrium-90 (Y-90) radioembolization. YRDose was implemented in Python as scripted modules within 3D Slicer 5.8.1. Mandatory inputs for the complete pre-therapy workflow are anatomical computed tomography (CT) and quantitative technetium-99m macroaggregated albumin single-photon emission computed tomography/CT image. Quantitative Y-90 PET/CT is optional for delivered-dose verification. The suite integrates CT-based segmentation with expert review, geometric alignment, binary-mask export, three-dimensional lung shunt fraction (LSF) calculation, compartment-based activity allocation, and mean absorbed-dose estimation using the Medical Internal Radiation Dose local energy deposition formalism. Segmentations, intermediate measurements, and final outputs are stored in a single Medical Reality Markup Language scene. The framework enabled sequential segmentation, volumetric LSF calculation, compartment mass estimation, planned activity calculation, and post-therapy mean absorbed-dose verification within the same software environment, preserving traceability and reproducibility. This technical note presents a reproducible open-source platform for Y-90 radioembolization planning and PET/CT dosimetry. YRDose provides an accessible research framework for developing, testing, and auditing image-based personalized dosimetry workflows, particularly in institutions without proprietary platforms. Formal validation remains necessary before routine clinical adoption.
AIM:Assessment of maximum standardized uptake value (SUVmax) values and patterns of uptake on 68Ga prostate-specific membrane antigen (PSMA) PET/computed tomography (CT) in benign and malignant prostatic lesions. METHODS:Retrospective observational study of prostate cancer patients referred for 68Ga-PSMA PET/CT for initial staging. SUVmax of the prostatic lesion was correlated with risk category, International Society of Urological Pathology (ISUP) grade groups, prostate-specific antigen (PSA), and Gleason score. Uptake patterns across risk categories were also evaluated. RESULTS:A total of 325 subjects were included (14 benign and 311 malignant). Median SUVmax of benign lesions was 8.29. Grade groups 4 and 5 showed significantly higher median SUVmax values (26.42 and 26.55) than other grade groups. SUVmax correlated positively with ISUP grade group, Gleason score, and serum PSA (all P < 0.001). SUVmax differed significantly among benign/low-, intermediate-, and high-risk groups. Receiver operating characteristic analysis identified an SUVmax cut-off of 10.91 for diagnosing prostate cancer, with 80% sensitivity, 79% specificity, 98.8% positive predictive value, and 80% diagnostic accuracy. Uptake pattern within the prostate did not differ significantly across risk categories. CONCLUSION:SUVmax differentiates high-risk from low- and intermediate-risk prostate cancer and may serve as a noninvasive independent prognostic marker. Intraprostatic uptake pattern has no significant role in lesion categorization.
INTRODUCTION:Biochemical recurrence (BCR) after radical prostatectomy occurs in 20-40% of patients. Prostate-specific membrane antigen (PSMA) PET/computed tomography (CT) is the preferred imaging modality for recurrence, but detection rates decline at low prostate-specific antigen (PSA) levels. The role of PSA kinetics in postradical prostatectomy BCR remains unclear. We evaluated the association between PSA kinetics and PSMA PET/CT positivity in postradical prostatectomy BCR. MATERIALS AND METHODS:We retrospectively analyzed postradical prostatectomy patients (2013-2024) who developed BCR and underwent 68Ga-PSMA PET/CT. Patients with prior therapy, PSA persistence, inadequate follow-up, or non-PSMA imaging were excluded. Clinicopathological and PSA kinetic variables were compared between groups. Logistic regression assessed associations with PET positivity, and receiver operating characteristic (ROC) analysis identified exploratory cut-offs. RESULTS:Of 973 men who underwent radical prostatectomy, 64 met the inclusion criteria. Nineteen (29.7%) had positive and 45 (70.3%) had negative scans. Baseline characteristics were comparable. Median PSA at imaging was 0.30 ng/ml. PET-positive patients had higher PSA velocity (PSAV) (0.58 vs. 0.27 ng/ml/year; P = 0.020) and shorter PSA doubling time (PSADT) (3.23 vs. 5.80 months; P = 0.009). On univariable analysis, PSAV [odds ratio (OR): 3.31, P = 0.027), PSADT (OR: 0.86, P = 0.050), and PSA at imaging (OR: 10.68, P = 0.032) were associated with PET positivity. ROC analysis showed moderate discrimination for PSADT (AUC: 0.71) and PSAV (AUC: 0.69). CONCLUSION:Shorter PSADT and higher PSAV predicted PSMA PET positivity in men with BCR after radical prostatectomy. Exploratory cut-offs of PSADT less than 3.9 months and PSAV more than 0.54 ng/ml/year were identified but require external validation.
OBJECTIVE:Ischemic heart disease is driven by systemic immunonutritional disruptions rather than isolated epicardial stenoses. We investigated the diagnostic utility of the Gustave Roussy immune score (GRIS) and Naples prognostic score (NPS) in predicting ischemia, scar burden, and high-risk markers on myocardial perfusion imaging (MPI) in suspected stable coronary artery disease. METHODS:This retrospective cohort included 325 patients (193 men; mean age, 60 years) undergoing ECG-gated single-photon emission computed tomography MPI. Patients were stratified into normal, ischemia, scar, and mixed groups. Routine blood parameters yielded the neutrophil-to-lymphocyte ratio (NLR), systemic immune-inflammation index (SII), NPS, and GRIS. RESULTS:Inflammatory indices (NLR, SII) and complex scores (NPS, GRIS) were significantly elevated in the ischemia and scar groups versus the normal perfusion group (P < 0.001). In multivariable analysis, GRIS - integrating cellular destruction and nutritional depletion with inflammation - was the strongest independent predictor of myocardial perfusion abnormalities (odds ratio: 10.57; 95% confidence interval: 5.11-21.89; P < 0.001), outperforming all other indices (area under the curve: 0.770; 86.3% specificity at >1 cutoff). Furthermore, elevated GRIS and NPS independently predicted poor prognosis (scar or reduced left ventricular ejection fraction) and transient ischemic dilation (>1.22) (P < 0.05). CONCLUSION:GRIS and NPS significantly outperform traditional inflammatory indices in detecting myocardial ischemia and cellular reserve depletion. Derived from routine blood tests, GRIS serves as a powerful clinical 'gatekeeper' before invasive procedures, effectively identifying patients with high biological frailty.
BACKGROUND:Accurate preoperative prediction of lymph node metastasis (LNM) guides treatment and prognostic stratification for pancreatic ductal adenocarcinoma (PDAC). This study established an interpretable PET/computed tomography (CT)-based artificial intelligence model combining clinical indicators, radiomic and 2.5D deep learning features to predict preoperative LNM. METHODS:A total of 173 pathologically confirmed PDAC patients with preoperative 18F-fluorodeoxyglucose PET/CT scans were retrospectively enrolled and randomly split into training and test sets at a 7 : 3 ratio. Clinical indicators, PET/CT radiomic features and ResNet50-based 2.5D deep learning features were extracted. Feature selection was implemented via, Spearman correlation analysis and logistic regression. Seven machine learning algorithms were built and compared: support vector machine, logistic regression, random forest, extra trees, gradient boosting machine (GBM), k-nearest neighbors and linear discriminant analysis (LDA). Model performance was assessed by receiver operating characteristics curve, DeLong test, calibration curve, Hosmer-Lemeshow test and decision curve analysis, and Shapley Additive Explanations (SHAP) were used for model interpretability. RESULTS:Among 173 patients, 105 were LNM-positive and 68 were LNM-negative. The GBM model achieved the highest area under the curve (AUC) of 0.970 in the training set with suspected overfitting. On the independent test set, LDA yielded optimal performance (AUC = 0.871, accuracy = 0.792, sensitivity = 0.719, specificity = 0.905, F1 = 0.807). Decision curve analysis verified favorable clinical applicability. SHAP analysis indicated PET/CT-derived deep learning and radiomic features exerted stronger predictive effects than conventional clinical variables. CONCLUSION:This interpretable PET/CT-based model provides a noninvasive tool for individualized preoperative LNM risk assessment in PDAC.
Objective To characterize publication growth, modality trends, and thematic evolution in prostate-specific membrane antigen (PSMA) radioligand therapy (RLT) for prostate cancer from 2015 to 2025, emphasizing beta-emitting RLT, targeted alpha therapy, and dosimetry-related terminology. Methods The Web of Science Core Collection was searched using a prespecified topic strategy. A fixed bibliographic snapshot was exported on 1 January 2026, covering records through 31 December 2025. English-language articles and reviews were included. After screening and postexport cleaning, 908 publications underwent bibliometric analysis using bibliometrix, keyword mapping, and reference co-citation analysis. Therapeutic modality was assigned by deterministic text mining of titles, abstracts, and keywords with a prespecified alpha-priority rule; dual-label analyses assessed alpha/beta co-mentioning. Dosimetry-related terminology was identified using prespecified dictionaries. Two reviewers independently assessed modality in a random sample of 200 records. Results Annual output increased from four publications in 2015 to 199 in 2025, although 2025 counts should be interpreted cautiously because of possible indexing delay. Under the primary classification, beta-emitting RLT predominated (698/908, 76.9%), whereas alpha-therapy-related publications accounted for 193/908 (21.3%). Under dual labeling, 149/908 publications (16.4%) co-mentioned alpha- and beta-based approaches. Dosimetry-related terminology increased over time and stabilized at approximately one-third of annual output after 2020. Inter-reviewer agreement was nearly perfect (kappa, 0.947–0.949). Conclusion The PSMA RLT literature expanded rapidly and remained dominated by beta-emitting therapy, with increasing alpha-therapy activity and broader incorporation of dosimetry-related terminology. These bibliometric findings characterize publication-level trajectories in PSMA RLT research and suggest priorities for standardized reporting, scalable dosimetry, and prospective treatment-optimization studies.
Relapsing polychondritis is a rare chronic autoimmune inflammation of the cartilage associated with life-threatening respiratory complications. Currently, no clear role of imaging modalities such as 18F-fluorodeoxyglucose (FDG) PET/computed tomography (CT) is defined in the literature. This systematic review and meta-analysis provide current evidence on the PET-positivity rate and utility in relapsing polychondritis. Prospective or retrospective studies with more than five patients of suspected relapsing polychondritis who underwent 18F-FDG PET/CT during their management and reported a PET-positivity rate were included. Low-sample-size studies describing chondritis due to other aetiologies or utilizing PET-based radiopharmaceuticals other than FDG were excluded. A systematic search using relevant keywords was conducted across four databases (PubMed, Embase, Scopus and Web of Science) to include studies up to 25 April 2025. The Joanna Briggs Institute critical appraisal tools were used for risk-of-bias analysis. Data were analysed using the R software package (v4.3.1; 2023). Out of 962 articles, three with a total of 97 patients were included. With a pooled PET-positivity rate of 94% [95% confidence interval (CI): 73-99%, I2 = 0%, P = 0.76] and a pooled baseline SUVmax of 4.0 (95% CI: 3.5-4.6, I2 = 32%, P = 0.23), 18F-FDG PET identified asymptomatic cartilage involvement in more than 25% patients and PET parameters correlated well with inflammatory markers. It had a higher positivity rate for inaccessible sites, such as peripheral airways, and was crucial in treatment monitoring. The pooled PET-positivity rate of 18F-FDG PET in relapsing polychondritis is high but requires prospective large-sample-size studies to explore the diagnostic accuracy and prognostic implications of 18F-FDG PET in relapsing polychondritis.
AIM:Gallium-68 fibroblast activation protein inhibitor-04 PET-computed tomography ( 68 Ga-FAPi-04 PET-CT) imaging is a promising modality with higher tumor affinity and lower background activity than 18 F-fluorodeoxyglucose, especially for brain imaging, which has no significant physiological uptake. This study aimed to determine the uptake of high-grade glioma lesions in correlation with histopathological FAP expression and to assess the contribution of imaging accordingly. MATERIALS AND METHODS:Fifteen patients with high-grade gliomas (WHO grade 3 and 4) were the subjects of this study. The patients presented with suspicion of recurrent tumors, which were determined by MRI imaging. 68 Ga-FAPi-04 PET-CT was performed on all subjects. The images were analyzed by visual and quantitative evaluation, which was compared with FAP expression determined from the pathology specimens, and all results were compared with the follow-up results (progression) at 12.2 ± 14.6 months. RESULTS:PET-CT imaging revealed an area under the curve of 0.97 for the tumor-to-background ratio of 14.3, with 100% sensitivity and 88.9% specificity for predicting progression in this small patient cohort ( Fig. 1 ). In addition, whole-body imaging revealed suspicion of bone metastasis in three patients and liver metastasis in one patient, but validation was not possible because of short survival after imaging. CONCLUSION:Although the sample size is limited, Ga-FAPi-04 PET-CT imaging showed high diagnostic value for recurrent tumors, as tumor-to-background ratio values correlate with prognosis. In addition, a theranostic approach using these radiopharmaceuticals might yield favorable results in further studies.
Fibroblast activation protein inhibitor (FAPI) PET/computed tomography (CT) is an emerging molecular-imaging approach for inflammatory bowel disease (IBD), particularly where fibroblast activation, stromal remodeling, and fibrosis are clinically relevant. Fluorodeoxyglucose (FDG) PET reflects inflammatory glucose metabolism but may be limited by physiologic bowel uptake and poor fibrosis specificity. To review original human studies evaluating FAPI-PET and FDG-PET in IBD, perform exploratory comparative synthesis where extractable data permitted, and appraise the ulcerative colitis-specific evidence base. Original human studies of FAPI-PET and FDG-PET in Crohn disease, ulcerative colitis, or mixed IBD cohorts were identified and categorized as direct comparative, supportive FAPI, or supportive FDG studies. Extractable 2 × 2 diagnostic data were summarized descriptively. Sensitivity analyses were performed by reference standard type and by excluding surgical or stricturing-enriched cohorts where feasible. Eleven original studies were included, of which four formed the direct comparative core. Three studies contributed segment-level 2 × 2 data to the primary lesion detection dataset, including Crohn disease and ulcerative colitis cohorts and different FAPI radiopharmaceuticals. In this exploratory segment-level aggregate, FAPI-PET showed descriptively higher sensitivity, specificity, accuracy, and diagnostic odds-ratio than FDG-PET. Restriction to endoscopy-referenced cohorts preserved the direction of effect. Patient-level 2 × 2 tables were not uniformly reported, so patient-level pooled estimates could not be generated. FAPI-PET is a promising imaging modality in IBD, with the strongest evidence in Crohn disease and fibrostenotic characterization. In ulcerative colitis, direct comparative evidence remains sparse.
AIM:The study aimed to analyze the diagnostic utility of fluoro-deoxy glucose [FDG PET/computed tomography (CT)] in assessing peritoneal deposits and to establish optimal quantitative metabolic thresholds for differentiating malignant from benign involvement, comparing it with conventional CT. METHOD:A total of 202 patients who had been identified with various types of malignant tumors and who were suspected or confirmed to have peritoneal deposits underwent whole-body FDG PET/CT. Qualitative assessment and quantitative metabolic parameters, including standardized uptake value (SUVmax, SUVmean, and SUVpeak), metabolic tumor volume, and total lesion glycolysis, were evaluated. Results were validated against histopathology or clinical/radiological follow-up. Receiver operating characteristic curve analysis determined the discriminative power and optimal cut-off values. RESULT:FDG PET/CT demonstrated superior diagnostic accuracy, identifying 181 true positive cases with an overall sensitivity of 98.4%. Only three false negative cases were reported in the primary PET/CT analysis; however, further histological correlation of all cases revealed that lower FDG avidity was notably associated with specific subtypes, such as mucinous and signet ring cell carcinomas. In contrast, conventional CT reported only 126 true positive cases and a high rate of false negative (28.7%, n = 58) with a specificity of 46.6% and sensitivity of 69.5%. Among metabolic metrics, SUVmax, SUVmean, and SUVpeak showed nearly the same diagnostic performance, with an area under the curve of (0.915, 0.916, and 0.910), respectively (P = 0.0001). These values indicate 'excellent' power in distinguishing malignant from benign lesions. CONCLUSION:FDG PET/CT performs noticeably better than traditional CT in the identification and mapping of peritoneal deposits, especially when anatomical alterations are minor. The high discriminative power of SUV-based metrics, especially with a threshold of 1, provides an excellent discriminative power in distinguishing malignant from nonmalignant lesions.
OBJECTIVE:This study aimed to evaluate the prognostic significance of baseline 18F-fluorodeoxyglucose PET/computed tomography-derived metabolic tumor volume (MTV) and maximum standardized uptake value (SUVmax) for treatment outcome in pediatric Hodgkin lymphoma. METHODS:We retrospectively analyzed 48 patients aged less than or equal to 18 years with newly diagnosed intermediate-risk Hodgkin lymphoma who underwent baseline 18F-fluorodeoxyglucose PET/computed tomography between January 2020 and December 2025 at Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Pakistan. Baseline MTV and SUVmax were quantified and assessed for association with treatment outcomes. The primary endpoint was event-free survival (EFS). RESULTS:Median baseline MTV was 263.5 ml (range: 22-781) and median SUVmax was 9.2 (range: 3.2-31.8). After a median follow-up of 48.8 months, 14 (29.2%) patients experienced an EFS event. MTV was higher in patients with events than in those without (303.0 vs. 254.5 ml), but the difference was not significant (P = 0.212). SUVmax was also nonpredictive (P = 0.834). EFS was 63.6% in the high-MTV group versus 86.7% in the low-MTV group (Fisher's exact P = 0.171; log-rank P = 0.194). MTV and SUVmax showed a weak, nonsignificant correlation (ρ = 0.173, P = 0.244). Disease stage was the only significant prognostic factor (P = 0.010). Receiver operating characteristics analysis demonstrated modest discriminatory ability for MTV [area under the curve (AUC) = 0.617], whereas SUVmax showed none (AUC = 0.479). CONCLUSION:In this single-center cohort, baseline MTV and SUVmax were not significantly predictive of EFS, with disease stage remained the only significant prognostic determinant. However, given the limited statistical power inherent to this sample size, a clinically meaningful association cannot be excluded and warrants evaluation in larger prospective studies.
