EJNMMI Research最新文献

Background: [¹⁸F]FDG PET-CT scan has a lower sensitivity in imaging of indolent non-Hodgkin's Lymphoma (NHL.) We aimed at identifying a threshold of clinical/pathological indicators which would independently predict [¹⁸F]FDG PET-CT scan positivity. For this purpose, we used a retrospective real-world cohort of NHL patients and then validated this criterion on [¹⁸F]FDG and [⁶⁸Ga]Pentixafor scans in a prospective indolent NHL cohort.

Results: In the retrospective real-world cohort of NHL, Ki67 was identified as an independent factor that influenced [¹⁸F]FDG uptake (r = 0.701). The cutoff value for Ki67 was 36.5% with a maximum area under the curve (AUC) of 0.811 and a Youden index of 0.494 for predicting [¹⁸F]FDG imaging positivity. The sensitivity of [¹⁸F]FDG PET in retrospective NHL cohort was only 65.2% (101/155) which further decreased to 46.3% in patients with Ki 67 ≤ 35%. In the prospective comparison of patients with Ki67 ≤ 35%, [⁶⁸Ga]Pentixafor had a higher sensitivity (80.6% (29/36)) than that of [¹⁸F]FDG PET-CT scan (30.6% (11/36)). However, in patients with Ki67 > 35%, both the imaging modalities had similar sensitivities of 60% (3/5).

Conclusion: A Ki67 of 35% was shown to be a promising threshold criterion for choosing between [¹⁸F]FDG or [⁶⁸Ga]Pentixafor PET tracer in patients with indolent NHL.

Trial registration: A Study Evaluating the Value of 68Ga-Pentixafor PET Imaging in the Staging of Hematological Tumor, and Comparing it With 18 F-FDG PET/CT Imaging, NCT06834412. Registered 13 February 2025 - Retrospectively registered, https://register.

Clinicaltrials: gov/prs/beta/studies/S000FBBP00000062 .

Background: Accurate pre- and intraoperative assessment of disease extent is crucial for curative treatment of colorectal liver metastases (CRLM) and primary colorectal cancer (pCRC). Tumour-targeted nuclear imaging can enhance pre- and postoperative tumour staging, while tumour-specific fluorescence-guided surgery can improve intraoperative visualization. However, validated targets remain limited, particularly for CRLM. This study aimed to identify and validate novel molecular targets for CRLM using a data-driven approach. Additional objectives included pCRC target expression and evaluating target expression in neoadjuvant-treated patients.

Results: Using a data-driven RNA-based discovery approach (Euretos), candidate targets for colorectal liver metastases were identified. Of these, the six highest-ranking targets-CEACAM5, EPCAM, CEACAM6, MUC13, FXYD3, and CDH17-were selected for validation through immunohistochemistry (IHC). Semi-automated image analysis quantified IHC staining intensity (0-100) for tumour epithelium and background on a per-pixel basis. A patient's staining pattern was regarded as positive if mean tumour epithelium scored positive (>25), background negative (<25) and tumour epithelium >25 points higher than background, referred to as relative positive expression. The proportion of CRLM samples showing relative positive expression was 79% for CEACAM5, 45% for EPCAM, 80% for CEACAM6, 24% for MUC13, 58% for FXYD3, and 22% for CDH17. CEACAM5/CEACAM6 combined positivity reached 90% (either one positive), showing that targeting both markers enables molecular imaging in nearly the entire population. Staining intensities were similar in pCRC epithelium (P >0.05). Neoadjuvant-treated CRLM exhibited higher expression for all targets.

Conclusion: Using a novel data-driven approach, six potential imaging targets were successfully identified and validated. CEACAM5 and CEACAM6 emerged as strong targets that, regardless of neoadjuvant therapy, covered nearly the entire CRLM population-supporting their further probe development and clinical translation.

Background: Sodium [¹⁸F]Fluoride Positron Emission Tomography (Na[¹⁸F]F PET) is a promising imaging biomarker for evaluating bone metabolism in spondyloarthritis (SpA) and other bone affecting diseases. Accurate quantification of tracer uptake is essential for assessing disease activity and treatment response. This study aimed to determine optimal simplified metrics for Na[¹⁸F]F uptake and evaluate their performance compared to net influx rate (K_i).

Results: A prospective study included 54 SpA patients undergoing Na[¹⁸F]F PET/CT scans at baseline and after 12 weeks of therapy. Dynamic PET in combination with venous blood sampling was analyzed to derive kinetic parameters, including K_i in 43 scans that included pathological uptake in the dynamic field of view. Semi-quantitative standardized uptake values (SUVs) corrected body weight (BW), lean body mass (LBM), body surface area (BSA) and skeletal volume (SV) were compared and correlations between K_i and SUVs were assessed cross-sectionally and longitudinally. Based on analysis of the blood sample data, there was a significant difference between SUV corrected for BW between patients who weighted more and less than 85 kg (p < 0.01 at all sample moments). When LBM or SV was used, this difference disappeared (p > 0.05). There was a significant correlation between K_i and various SUV-metrics, with SUV_peak-LBM at 25-30 min yielding the highest correlation both cross-sectionally (R² = 0.77, p < 0.01), and longitudinally (R² = 0.54, p < 0.01).

Conclusions: Na[¹⁸F]F uptake quantification of lesions in the axial skeleton of SpA patients can be performed cross-sectionally and longitudinally with simplified uptake measures, particularly SUV_peak, normalized using LBM or SV. This offers a more reliable approach to evaluating disease activity and treatment responses compared to BW.

Background: Pneumoconiosis, characterized by dust-induced pulmonary fibrosis, lacks reliable methods to assess fibrotic activity. This study aimed to monitor fibroblast activation and identify activated pulmonary fibrosis for early diagnosis and anti-fibrotic therapy response by ¹⁸F-fibroblast activation protein inhibitors (FAPI) positron emission tomography/computed tomography (PET/CT) in pneumoconiosis.

Methods: A single-center prospective clinical study was conducted on 6 pneumoconiosis patients and 4 healthy control individuals. The uptake of ¹⁸F-FAPI in the pulmonary fibrosis areas of participants and its correlation with pulmonary diffusion function were analyzed. Sprague-Dawley rat experiments were performed on three groups including pneumoconiosis model, pirfenidone-treated, and normal control groups. ¹⁸F-FAPI and ¹⁸F-fluoro-D-glucose (FDG) PET/CT, histopathologic, and hematological analysis were assessed monthly from modeling until 6 months.

Results: In our preliminary cohort, compared to the controls, the ¹⁸F-FAPI uptake in fibrotic areas of pneumoconiosis patients was higher, and a strong negative correlation with the diffusing function was observed (r = -0.929, P = 0.022). In the pneumoconiosis model, ¹⁸F-FAPI activity peaked one month earlier than relative collagen content (%) in Masson trichrome staining and the level of connective tissue growth factor in plasma, an indicator reflecting the fibroblast activation. The uptake of ¹⁸F-FAPI in the pirfenidone-treated group significantly decreased compared to the pneumoconiosis group. Additionally, in pneumoconiosis rats, ¹⁸F-FDG uptake peaked at Month 3, correlating with progressive inflammation (granuloma formation, elevated interleukin-6 [IL-6]/tumor necrosis factor-α [TNF-α]), while pirfenidone showed timepoint-specific metabolic reduction, no significant difference in the overall mean standardized uptake value (SUVmean) was observed.

Conclusions: ¹⁸F-FAPI PET/CT imaging may hold promise for identifying active pulmonary fibrosis and monitoring its progression in pneumoconiosis, suggesting a potential clinical opportunity for targeted anti-fibrotic treatment. These preliminary findings warrant further investigation in larger studies.

Background: Isotopic renography is pivotal for assessing upper urinary tract obstruction and provides renal functional parameters. New 3D-CZT cameras offer enhanced sensitivity and innovative full SPECT protocols that need to be validated on phantoms. Current renal phantoms are often complex and suitable for 2D imaging. Using a new printed 3D renal phantom, we compared planar and full SPECT dynamic imaging.

Methods: A 3D-printed renal phantom mimicking pediatric/adult kidneys was designed. Each kidney subunit, connected to a bladder-bag, was programmably infused with 7.5 MBq of [^99mTc]-Pertechnetate to simulate normal nephrograms. An asymmetry of renal activity was simulated using different activity ratios. Each acquisition was conducted on both conventional NaI(Tl) and 3D-CZT cameras.

Results: The 3D printed phantom enabled the acquisition of consistent and reproducible nephrograms. T_max, T_1/2, and A_{20 - min/max} ratios showed no statistically significant differences between planar and SPECT. Simulated asymmetric renal function demonstrated a strong linear correlation between activity and AUC with r = 0.9455 and 0.9471 (p < 0.0001), respectively for conventional and 3D cameras.

Conclusion: This innovative 3D phantom allowed the acquisition of reproducible nephrograms with parameters comparable to those of clinical examinations. At low activity, 3D-CZT camera acquisitions provided equivalent values to conventional cameras, supporting their use for qualitative imaging and follow-up.