European Journal of Nuclear Medicine and Molecular Imaging最新文献

Background

Giant cell arteritis (GCA) is a difficult to diagnose large vessel vasculitis. CDUS, FDG-PET/CT and MRI are increasingly used for GCA diagnosis. This study aims to assess vascular wall lesions in GCA suspected patients, directly comparing CDUS, FDG-PET/CT and MRI with each other.

Methods

In a nested-case control study, consecutive GCA suspected patients were included. Scans were retrospectively assessed by two experts per imaging modality. Inter- and intraobserver agreement using Cohen’s or Fleiss Kappa were calculated to assess agreement between experts, a few duplicated scans and between imaging modalities. Sensitivity and specificity of the imaging modalities for overall diagnostic performance and for individual arteries were calculated.

Results

In total, 42 patients were included. Overall diagnostic performance of imaging modalities was comparable. Sensitivity and specificity were highest in the temporal artery for CDUS (76% and 93%; Kappa > 0.7) and MRI (60% and 100%; Kappa > 0.7), and in the vertebral (61% and 100%; Kappa 0.56) and maxillary artery (52% and 100%; Kappa 0.75) for FDG-PET/CT. Agreement between all modalities for a positive temporal artery was 0.76, but only 0.28 between CDUS and FDG-PET/CT. Agreement for the axillary artery was 0.7 between CDUS and FDG-PET/CT.

Conclusion

The temporal artery can be assessed by CDUS and MRI with good sensitivity and high specificity, and the axillary artery by CDUS and FDG-PET/CT with high agreement between the two modalities. In addition, the vertebral and maxillary artery can be assessed by FDG-PET/CT with good sensitivity and specificity, however the vertebral artery had moderate interobserver agreement.

Purpose: Several prostate-specific membrane antigen (PSMA) radiopharmaceuticals have been used for the treatment of metastatic, castration-resistant prostate cancer (mCRPC). In an attempt to improve the tumour accumulation, new PSMA ligands were developed with an albumin-binding entity to enhance the blood circulation and, hence, tumour accumulation. In preclinical studies, [¹⁷⁷Lu]Lu-SibuDAB, a radiopharmaceutical with moderate albumin-binding properties, outperformed [¹⁷⁷Lu]Lu-PSMA-617 and [¹⁷⁷Lu]Lu-PSMA-I&T. The aim of this study was to evaluate the dosimetry of [¹⁷⁷Lu]Lu-SibuDAB in patients diagnosed mCRPC.

Methods: Seventeen patients (median age 72 years, range 63‒83) diagnosed with progressive disease of mCRPC were included in this prospective study after exhausting all available treatment options. They were injected with 5.3 ± 0.5 GBq (mean ± standard deviation) [¹⁷⁷Lu]Lu-SibuDAB as a first treatment cycle. Sixteen of these patients underwent sequential whole-body SPECT/CT and activity determination in venous blood samples for dosimetry purposes. Absorbed doses to the salivary glands, liver, spleen, kidneys, and red marrow as well as selected tumour lesions were calculated in OLINDA/EXM™ and compared to published values for previously established PSMA radiopharmaceuticals.

Results: Absorbed dose coefficients (ADC) to tumours (9.9 ± 5.4 Gy/GBq) were about 2-fold higher than those reported for clinically approved PSMA radiopharmaceuticals. ADC to salivary glands, liver, spleen, kidneys and red marrow were higher (0.5 ± 0.2, 0.2 ± 0.05, 0.2 ± 0.1, 1.8 ± 0.6, 0.1 ± 0.04 Gy/GBq, respectively) than for [¹⁷⁷Lu]Lu-PSMA-617 and [¹⁷⁷Lu]Lu-PSMA-I&T, but lower than for [¹⁷⁷Lu]Lu-PSMA-ALB-56, a previously investigated long-circulating PSMA radiopharmaceutical. The tumour-to-kidneys, tumour-to-red marrow, tumour-to-salivary glands ADC ratio were 6.6, 102, 33.1. These ratios were comparable to those of [¹⁷⁷Lu]Lu-PSMA-617 and [¹⁷⁷Lu]Lu-PSMA-I&T for kidneys and red-marrow, but higher for salivary glands.

Conclusion: [¹⁷⁷Lu]Lu-SibuDAB showed a prolonged blood circulation time and, hence, a significantly increased absorbed tumour dose, while tumour-to-organ ADC ratios were similar to conventional PSMA radiopharmaceuticals. Further clinical investigations to evaluate the efficacy and safety of [¹⁷⁷Lu]Lu-SibuDAB are, thus, warranted.

Purpose: To assess the influence of long-axial field-of-view (LAFOV) PET/CT systems on radiomics feature reliability, to assess the suitability for short-duration or low-activity acquisitions for textural feature analysis and to investigate the influence of acceptance angle.

Methods: 34 patients were analysed: twelve patients underwent oncological 2-[18F]-FDG PET/CT, fourteen [18F]PSMA-1007 and eight [68Ga]Ga-DOTATOC. Data were obtained using a 106 cm LAFOV system for 10 min. Sinograms were generated from list-mode data corresponding to scan durations of 2, 5, 10, 20, 30, 60, 120, 240, 360 and 600s using both standard (minimum ring difference MRD 85 crystals) and maximum acceptance angles (MRD 322). Target lesions were segmented and radiomics features were calculated. To assess feature correlation, Pearson's product-moment correlation coefficient (PPMCC) was calculated with respect to the full duration acquisition for MRD 85 and 322 respectively. The number of features with excellent (r > 0.9), moderate (r > 0.7 and < 0.9) and poor (r ≤ 0.7) correlation was compared as a measure of feature stability. Intra-class heterogeneity was assessed by means of the quartile coefficient of dispersion.

Results: As expected, PPMCC improved with acquisition time for all features. By 240s almost all features showed at least moderate agreement with the full count (C100%) data, and by 360s almost all showed excellent agreement. Compared to standard-axial field of view (SAFOV) equivalent scans, fewer features showed moderate or poor agreement, and this was most pronounced for [68Ga]Ga-DOTATOC. Data obtained at C100% at MRD 322 were better able to capture between-patient heterogeneities.

Conclusion: The improved feature reliability at longer acquisition times and higher MRD demonstrate the advantages of high sensitivity LAFOV systems for reproducible and low-noise data. High fidelity between MRD 85 and MRD 322 was seen at all scan durations > 2s. When contrasted with data comparable to a simulated SAFOV acquisition, full-count and full-MRD data were better able to capture underlying feature heterogeneities.

Purpose: Tumor-to-background ratio (TBR) is a critical metric in oncologic PET imaging. This study aims to enhance the TBR of [¹⁸F]FET in brain tumor imaging by substituting deuterium ("D") for hydrogen ("H"), thereby improving the diagnostic sensitivity and accuracy.

Methods: [¹⁸F]d₄-FET was synthesised by two automated radiochemistry modules. Biodistribution studies and imaging efficacy were evaluated in vivo  and ex vivo in rodent models, while metabolic stability and radiation dosimetry were assessed in non-human primates. Additionally, preliminary imaging evaluations were carried out in five brain tumor patients: three glioma patients underwent imaging with both [¹⁸F]d₄-FET and [¹⁸F]FET, and two patients with brain metastases were imaged using [¹⁸F]d₄-FET and [¹⁸F]FDG.

Results: [¹⁸F]d₄-FET demonstrated high radiochemical purity and yield. PET/MRI in rodent models demonstrated superior TBR for [¹⁸F]d₄-FET compared to [¹⁸F]FET, and autoradiography showed tumor margins that correlated well with pathological extents. Studies in cynomolgus monkeys indicated comparable in vivo stability and effective dose with [¹⁸F]FET. In glioma patients, [¹⁸F]d₄-FET showed enhanced TBR, while in patients with brain metastases, [¹⁸F]d₄-FET displayed superior lesion delineation compared to [¹⁸F]FDG, especially in smaller metastatic sites.

Conclusion: We successfully synthesized the novel PET radiotracer [¹⁸F]d₄-FET, which retains the advantageous properties of [¹⁸F]FET while potentially enhancing TBR for glioma imaging. Preliminary studies indicate excellent stability, efficacy, and sensitivity of [¹⁸F]d₄-FET, suggesting its potential in clinical evaluations of brain tumors.

Trial registration: ChiCTR2400081576, registration date: 2024-03-05, https://www.chictr.org.cn/bin/project/edit?pid=206162.

Purpose: Remote ischemic periconditioning (RIPC) has demonstrated cardioprotective effects and improved clinical outcomes as an adjunct to emergent percutaneous coronary intervention (PCI) in patients with ST-elevation myocardial infarction (STEMI). However, whether RIPC affects the cardiac sympathetic nerve activity in patients with STEMI remains unclear. This study investigated the effects of RIPC on cardiac sympathetic nerve activity in patients with STEMI.

Methods: We prospectively assigned patients with STEMI who underwent emergent PCI to receive RIPC or no procedure (control group) upon arrival at the cardiac catheterization laboratory. The primary endpoint was cardiac sympathetic nerve activity assessed through the washout rate (WR) in cardiac ¹²³I-metaiodobenzylguanidine (¹²³I-MIBG) imaging.

Results: Patients in the RIPC (n = 62) and control (n = 60) groups had similar demographic and clinical characteristics at baseline. Multivariable linear regression models revealed that the culprit lesion of the left anterior descending artery and hemoglobin level were significantly and independently associated with WR at discharge. WRs of the groups differed insignificantly at discharge. However, the RIPC group (n = 49) showed significantly lower WR than the control group (n = 47) at 1 year after discharge (p = 0.027). In the single-photon emission computed tomography analysis at 1 year after discharge, the RIPC group demonstrated significantly higher late uptake (p = 0.021) and lower WR (p = 0.013) in the nonculprit lesion, with a non-significant decrease in WR for the culprit lesion.

Conclusion: RIPC can suppress augmented cardiac sympathetic nerve activity in patients with STEMI, particularly in nonculprit lesions.

Purpose: Sentinel lymph node biopsy (SLNB) has been recognized as "the gold standard" for axillary staging in early breast cancer patients with clinically negative lymph nodes, resulting in significant morbidity decrease and quality of life improvement. This study aims to validate the performance of a newly developed handheld portable gamma camera (PGC) produced by Imagensys (Italy), in detecting and locating sentinel lymph nodes (SLNs) during the preoperative and intraoperative phases in breast cancer patients compared to conventional lymphoscintigraphy.

Methods: Adult female patients with histologically confirmed breast cancer, candidates for surgery and SLNB, were prospectively enrolled in this open-label, pre-marketing clinical trial. All patients underwent pre- operative assessment using both the PGC and conventional lymphoscintigraphy. The performance of the two devices was compared using the Poisson regression model for incidence rate ratios (IRRs). The intrinsic sensitivity of the devices was compared using the Wilcoxon Ranked Sign Test. The utility of PGC during intra-operative procedures was also evaluated. The manoeuvrability of the devices was evaluated using operator-satisfaction questioner.

Results: Sixty-eight patients (median age 50 years, BMI 21.4) were enrolled, including two patients with bilateral breast cancer, who underwent SLNB on both axillae. The PGC demonstrated superior preoperative lymph node detection rate (IRR 8.01, 95% CI 6.11-10.50; p < 0.0001) and intrinsic device sensitivity (mean counts per second 409 ± 286 vs. 255 ± 1173 for conventional device, p = 0.0003) compared to the conventional gamma camera. Intra-operative assessment with PGC was performed in 62 patients and no additional lymph nodes were visualised. However, the conventional gamma camera demonstrated superior manoeuvrability (p < 0.0001).

Conclusion: The PGC handheld gamma camera showed promising results for preoperative SLN assessment in patients with breast cancer. The limited manoeuvrability may be related to the operator's experience leading to higher inter-operator variability. Appropriate training and frequent use of nuclear medicine and surgical equipment could overcome this limitation.