Clinical and Translational Imaging最新文献

Background: The small molecule radiotracer ¹²⁴I-PU-H71 is an imaging biomarker of epichaperome formation. The tracer has been established to localize in tissues under chronic stress, specifically in cancer cells and neurodegenerative brain cells. A first-in-human imaging trial using positron emission tomography (PET) in cancer patients revealed unexpected tracer accumulation in the myocardium.

Purpose: To describe human ¹²⁴I-PU-H71 myocardial biodistribution and pharmacokinetics in a series of cancer patients with no history of cardiovascular disease.

Methods: 25 cancer patients (age 22-75 years, M:F - 7:18) with no history of cardiovascular disease received intravenous injections with microdose ¹²⁴I-PU-H71 while at rest, followed by dynamic and gated/non-gated PET image data acquisitions. Region-of-interest (ROI) analysis of left ventricular myocardium (LVmyo) and background left atrium quantified tracer concentrations as standardized uptake value (SUV) and uptake ratios. Kinetic rate constants were evaluated by a two-tissue compartment model.

Results: Myocardial accumulation of ¹²⁴I-PU-H71 was prominent in all patients, with median LVmyo SUVmean (interquartile range, IQR) of 2.8 (IQR, 2.13-3.29), 2.5 (IQR, 1.94-2.98), 2.4 (IQR, 1.73-3.31) and 1.0 (IQR, 0.61-2.45), and median LVmyo/blood-pool ratios of 1.9 (IQR, 1.57-2.38), 2.0 (IQR, 1.53-2.32), 3.6 (IQR, 2.91-4.06) and 3.9 (IQR, 2.62-5.08) at 1-9 min, 14-23 min, 3-4 h and 21-25 h, respectively on non-gated PET images. Myocardium showed peak uptake within 2 min post-injection, with sustained myocardial tracer-concentration at 4 h post-injection. Pharmacokinetic modeling revealed median K₁ = 0.45 ml/min/g (IQR, 0.38-0.62); k₂ = 0.47 min^{- 1} (IQR, 0.27-0.71); k₃ = 0.16 min^{- 1} (IQR, 0.09-0.26); and k₄ = 0.0038 min^{- 1} (IQR, 0.0015-0.0057). Regional assessment demonstrated essentially uniform tracer uptake in LV and myocardial segments; with normal LVEF in all patients (mean 57.7 ± 3.5%); and no patients suffered cardiac events over subsequent 12-month period.

Conclusion: Our study finds human myocardial epichaperome expression, as quantified by ¹²⁴I-PU-H71 PET. Our data indicates PU-H71 PET merits further study as a myocardial epichaperome biomarker, with potential application in drug development, possibly as a biomarker in subclinical cardiac dysfunction.

PSMA imaging is gaining importance in the field of oncology, both for diagnostic and therapeutic purposes. In this review, we aimed to highlight the significance of detecting brain metastases from prostate carcinoma before the onset of symptoms, also considering potential pitfalls and false-positive findings. To emphasize this aspect, we present a case report in which the use of an extended field of view to the vertex allowed to the localization of brain lesions before the onset of symptoms. The present clinical report describe the rare case of brain metastases from prostate carcinoma detected by [¹⁸F]F-PSMA-1007 PET/CT.

Objective

Although ¹⁸F-FDG PET/CT is helpful in detecting primary breast cancer and its distant metastases, ⁶⁸Ga-FAPI PET/CT may perform better in detecting primary breast cancers at an earlier stage and metastatic lesions (lymph node, etc.). This study aimed to systematically review the diagnostic value of ⁶⁸Ga-FAPI PET/CT versus ¹⁸F-FDG PET/CT in terms of diagnostic accuracy parameters (sensitivity, specificity) and quantitative parameters (SUVmax, TBR, etc.) for the diagnosis of primary and metastatic lesions of breast cancer.

Methods

This study followed the PRISMA guidelines for systematic reviews. A comprehensive search of the PubMed, EMBASE and Web of Science databases was performed to identify studies that met the eligibility criteria from 2000–01 to 2023–07. The quality of the relevant studies with the QUADAS-2 method was assessed via ReviewManager v.5 software. The literature included female breast cancer patients with the pathologic type of invasive carcinoma who had received both ¹⁸F-FDG and ⁶⁸Ga-FAPI PET/CT.

Results

A total of 238 documents were retrieved, and 6 were ultimately included. The results revealed that ⁶⁸Ga-FAPI PET/CT had a greater SUVmax, TBR, and sensitivity than FDG did.

Conclusion

In this study, we compared the value of ⁶⁸Ga-FAPI PET/CT and ¹⁸F-FDG PET/CT in breast cancer patients. For both primary and metastatic foci of breast cancer, ⁶⁸Ga-FAPI PET/CT resulted in a higher lesion detection rate and tracer uptake. Second, ⁶⁸Ga-FAPI PET/CT can improve patient staging and provide some prognostic information, including the pathological response. In addition, ⁶⁸Ga-FAPI PET/CT imaging can detect additional lesions as a complementary tool.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier (CRD42023491138).

Purpose

This retrospective analysis aims to study the relationship between tracer uptake in sentinel lymph nodes (SLNs) as measured on SPECT/CT and during intra-operative gamma tracing with a drop-in gamma probe (SENSEI^®) in patients who participated in the UZ Leuven cohort of a prospective multicentre clinical trial evaluating the SENSEI^® probe for minimally-invasive SLN biopsy (SLNB) in prostate cancer. Correlation of pre- and intraoperative imaging can allow for improved surgical planning, providing important information to guide intraoperative findings.

Methods

Nine patients with histologically proven prostate cancer scheduled for radical prostatectomy (RP) with extended pelvic lymph node dissection (ePLND) were prospectively selected for preoperative lymphoscintigraphy with SPECT/CT the day before surgery after intra-prostatic injection of 240 MBq of ^99mTc-nanocolloid under ultrasound guidance. SLNB was performed with the SENSEI^® drop-in gamma probe during standard of care RP with ePLND. SLN detection and counts on SPECT/CT and in vivo and ex vivo probe measurements were compared.

Results

The patient-based detection rate of at least one SLN was 100% on SPECT/CT and 100% intraoperatively with the drop-in gamma probe. In total, 29 SLNs were detected with the probe and 32 SLNs on SPECT/CT. The correlation between SPECT/CT counts and in vivo and ex vivo probe measurements was significant but moderate (Pearson r = 0.57, p = 0.002 and r = 0.64, p = 0.0003, respectively).

Conclusions

Drop-in gamma probe measurements showed a moderate correlation with the SPECT/CT counts. SPECT/CT uptake values can be used as an estimate for in vivo detection of SLNs with the probe.

Purpose

This research synthesis investigates the diagnostic performance of [¹⁸F]FDG PET/CT, MRI, and CT in detecting mandibular invasion in patients with oral and oropharyngeal cancer.

Methods

An extensive literature review was conducted using PubMed and Embase, targeting studies up to March 2024 that examined the diagnostic capabilities of [¹⁸F]FDG PET/CT, MRI, and CT for oral and oropharyngeal cancer patients. Sensitivity and specificity were calculated using the DerSimonian and Laird random-effects model with adjustments via the Freeman-Tukey double arc sine transformation. Study quality was assessed with the QUADAS-2 tool.

Results

This meta-analysis synthesized data from 24 studies involving 1376 participants to compare the diagnostic performance of CT, MRI, and [¹⁸F]FDG PET/CT for mandibular invasion in oral and oropharyngeal cancer patients. The results showed closely matched sensitivity and specificity among the technologies: CT pooled a sensitivity of 0.80 and specificity of 0.85, while MRI exhibited a slightly better sensitivity at 0.87 but lower specificity at 0.81, with the differences not reaching statistical significance (all P > 0.05). [¹⁸F]FDG PET/CT also demonstrated comparable performance, achieving a sensitivity of 0.77 versus CT’s 0.72 and a specificity of 0.82 versus CT’s 0.93, alongside matching MRI’s sensitivity at 0.86 and a specificity of 0.68 versus MRI’s 0.75, with all comparisons showing no significant disparities (all P > 0.05).

Conclusions

The meta-analysis concludes that there was no statistically significant difference in diagnostic performance between [¹⁸F]FDG PET/CT, CT and MRI. Further research with prospective comparative trials is recommended to validate these findings in new clinical cohorts.

Purpose

New-generation fully-digital PET/CT (dPET) scanners offer several technical advantages compared to analog (aPET) systems. This review aimed to summarize the current literature evidence about dPET technology clinical advantages.

Methods

A systematic literature search of PubMed/MEDLINE and Embase databases was performed following PRISMA guidelines. The full-text articles methodological quality was independently assessed by four authors using the CASP-diagnostic study checklist.

Results

Out of 510 articles, 81 were selected of which 42 related to oncology. In early-recurrent prostate cancer (PSA range ≤ 0.5 and 0.5–2.0 ng/ml), PSMA-dPET has shown a significantly higher detection rate compared to aPET especially for smaller lesions. A higher image quality and lesion detectability was reported in [¹⁸F]FDG studies on lung cancer and on mixed oncological cohorts, where metabolic TNM upstaging occurred in up to 32% of cases compared to aPET. dPET technology was also found to improve the localization of in-transit metastases in melanoma, the staging of early oral squamous cell carcinoma, as well as the accuracy of [⁶⁸ Ga]Ga-DOTA-TATE and ¹²⁴I imaging in neuroendocrine tumors and thyroid cancer respectively. Although dPET sensitivity can provide better image quality in diagnostic and therapeutic (⁹⁰Y-SIRT) applications, the possible higher rate of false positive findings (e.g., unspecific bone uptake at PSMA-1007), and SUV_max/radiomic-features variability should be considered. Main studies limitations included their retrospective nature, heterogeneity, and matched pair comparison design.

Conclusions

dPET has shown a diagnostic advantage over aPET in a variety of oncological settings, where the earlier and more accurate lesion localization and quantification could have relevant implications for optimal patient management.

Purpose

Positron Emission Tomography (PET) and Single Photon Emission Computerized Tomography (SPECT) allow the in-vivo evaluation of brain dopaminergic pathways’ integrity and functionality. A systematic review of published literature was performed to determine the usefulness of PET and SPECT for the assessment of dopaminergic pathways in patients with Huntington’s Disease (HD).

Methods

PubMed/Medline databases were searched to identify studies responding to our aim. Included articles were appraised using the Quality Assessment of Diagnostic Accuracy Studies criteria. Evaluation and discussion of data was then designed to assist clinicians identifying when (during patients’ course of the disease), how (through PET or SPECT) and why (depending on the findings) it would be useful to perform a functional assessment of dopaminergic pathways in patients with manifest and pre-manifest HD.

Results

Of 572 articles found, 33 were included in this systematic review, 6 among which evaluated the application of SPECT, and 27 the application of PET. Overall, there was an agreement in reporting dopaminergic system degeneration at both striatal and extra-striatal levels, often correlated with clinical and neuropsychological parameters. The non-linear progressive reduction of presynaptic dopamine transporter, vesicular monoamine transporter-2, or of post-synaptic dopamine receptors D1 and D2 was constantly described having a high potential of offering sensitive biomarkers of disease progression and response to disease-modifying interventions.

Conclusions

Despite limited literature data, this systematic review revealed that SPECT and PET are useful to monitor different aspects of striatal and extra-striatal dopaminergic pathways degeneration during all stages of HD and may serve for response to disease-modifying interventions assessment.

Purpose

Novel digital PET/CT (dPET) scanners with silicon photomultipliers (SiPM) present multiple technical improvements compared to analog PET (aPET) systems. This systematic review aimed to summarize the current literature evidence about the clinical advantages offered by dPET technology.

Methods

The PubMed/MEDLINE and Embase databases were systematically queried according to the PRISMA guidelines. Full texts were screened for eligibility and the methodological quality was evaluated by four independent authors using the CASP Diagnostic Study checklist.

Results

81 out of 510 articles were included (39 related to the non-oncologic setting). In patients with primary hyperparathyroidism, dPET has shown a significantly higher detection rate for hyperfunctioning glands, especially subcentimetric. dPET has also shown a higher image quality and diagnostic accuracy compared to aPET in the visual and semiquantitative assessment of metabolic impairment in patients with suspected neurodegenerative diseases. The enhanced quantification of dPET has also been leveraged in cardiovascular diseases, where ⁸²Rb dPET myocardial blood-flow assessment has shown potential to further advance the diagnostic and prognostic role of molecular imaging in coronary artery disease. Finally, dPET has allowed to optimize imaging protocols through reduced administered activities and/or scan times: a 3/3.5-fold reduced scan time was proven feasible in FDG/DOTA/PSMA imaging, thus allowing to limit radiation exposure, lower imaging costs and increase patient throughput.

Conclusions

dPET has shown improved diagnostic performance compared to aPET in multiple non-oncological settings owing to its higher detection rates, enhanced image quality and accurate quantification. dPET also enabled more personalized imaging protocols through reduced administered activities and/or scan times.

Purpose

To evaluate the role of experimental FAPI PET/CT in inflammatory bowel diseases.

Methods

First clinical papers about FAPI PET/CT in inflammatory bowel diseases were retrieved in scientific literature and commented in this short review, compared with conventional clinical and radiological examinations (e.g. CT, MRI and ¹⁸F-FDG PET/CT).

Results

Only few first-in-human trials have been published until now about the role of experimental FAPI PET/CT in inflammatory bowel diseases, showing interesting accuracy data and possible impact on clinical management in patients with Crohn’s disease.

Conclusion

Larger studies are needed to confirm and expand the role of this diagnostic tool in clinics.