BACKGROUND:Subclinical kidney allograft acute rejection (SCR) corresponds to "the unexpected histological evidence of acute rejection in a stable patient". The diagnosis of SCR relies on surveillance biopsy. Positron emission tomography (PET/CT) after injection of F18-fluorodeoxyglucose ([18F]FDG) has been proposed as a non-invasive screening approach. In the present multicenter prospective study, we assess the diagnostic yield [18F]FDGPET/CT to rule out SCR in stable KTR at 3 months post KTx. METHODS:From 01/2021-03/2025, we prospectively combined surveillance biopsy and [18F]FDGPET/CT at ~3 months post transplantation in adult kidney transplant recipients from 4 independent imaging centers. The mean standardized uptake value (mSUV) was measured in kidney cortex and referenced as a ratio to psoas muscle mSUV (mSUVR). RESULTS:Our multicenter cohort of 185 patients was categorized according to the Banff-2022 classification as: normal (n = 158); borderline (n = 18); SCR (n = 9, including 6 T-cell-mediated rejection and 3 microvascular inflammation). No significant correlation was observed between the mSUVR and ti score (R = 0.032, p-value = 0.67). The mSUVR reached 2.33 [1.97-2.93], 2.71 [2.50-3.33] and 2.42 [2.27-3.14] in normal, borderline and SCR groups, respectively. In multivariate models stratified by center, the risk of non-normal histology (n = 27, including borderline and SCR) increased with donor age (OR=1.05 [1.01-1.1], p = 0.02) but not with the mSUVR (OR=4.11 [0.91-18.48], p = 0.07). The Z-score of mSUVR was significantly associated with the risk of non-normal histology (OR=1.542 [1.02-2.33, p = 0.04). The risk of biopsy-proven SCR (n = 9) was not significantly associated with mSUVR. CONCLUSIONS:The mSUVR of [18F]FDG PET/CT does not reliably rule out SCR on surveillance biopsy.

Granulomatosis with polyangiitis is a rare disease that can lead to potentially fatal multisystem involvement if not properly or promptly managed. Early diagnosis is therefore crucial but may be challenging, especially because this condition often presents with nonspecific general symptoms. Sensitive imaging techniques, such as [18F]FDG PET/CT, can be useful for diagnosis, initial assessment of disease extent, and treatment response, potentially surpassing the conventional imaging methods typically used.

Hepatocellular carcinoma (HCC) is the most common primary hepatic tumour and represents a major diagnostic challenge. Conventional imaging, mainly based on computed tomography (CT) and magnetic resonance imaging (MRI), has some limitations, particularly in characterizing atypical and small lesions. Molecular imaging with [18F]Fluoro-2-deoxy-d-glucose, by positron emission tomography associated with computed tomography ([18F]FDG PET/CT), suffers from variable sensitivity depending on tumour differentiation. Recently, PET/CT imaging with prostate-specific membrane antigen (PSMA) showed growing interest in non prostatic tumours, especially in HCC due to its affinity for tumoural vascular endothelium. A case report illustrates the value of PSMA PET/CT in the staging and therapeutic management of HCC.

In the event of a prevascular mediastinal mass, knowledge of the anatomy and content of the mediastinum is an essential prerequisite to establish a differential diagnosis. The «4T» rule is applicable because it is a simple and effective mnemonic. It groups together; thyroid goiter, terrible lymphoma, teratoma and thymoma. The reference imaging technique is computed tomography with injection of iodinated contrast media, allowing the analysis of the lesion as well as its topography and its relationship with adjacent structures. Concerning the case of a lymphoma, PET/CT is the reference examination, as it allows a precise assessment of extension and can establish a target lesion for excisional biopsy which will make the definitive diagnosis. PET/CT is also used for therapeutic monitoring.

We present a 69-year-old woman who developed a lethal tumor lysis syndrome (TLS) after a first cycle of [ 177 Lu]Lu-DOTA-TATE, administered to treat a well-differentiated metastatic lung carcinoid tumor with liver, bone, and splenic progression. The patient developed diarrhea and general status deterioration rapidly after the injection, anuria, progressive consciousness disorder, and finally death in 48 hours. Laboratory analysis showed significant renal function impairment, hyperuricemia, and hyperphosphatemia, confirming the diagnosis. This case highlights a rare but deadly side effect of [ 177 Lu]Lu-DOTA-TATE and the precautions to be taken before treating high tumor burden patients.

BACKGROUND:Hepatocellular carcinoma (HCC) found in a non cirrhotic liver represents a minority of HCC cases and remains poorly studied. Due to its specific characteristics and evolution, this tumour requires a different management compared to HCC in a cirrhotic liver.CASE REPORT:The authors describe the case of a 68-year-old man diagnosed with a large giant and only mildly symptomatic HCC in a non-cirrhotic liver. The 23 cm HCC was discovered when a thoracoabdominal computed tomography was performed following mild abdominal pain. After a multidisciplinary discussion the tumour was judged to be borderline, but potentially resectable after neoadjuvant therapy and preparation for surgery. The patient underwent selective internal radiation therapy radioembolization of the right hepatic artery lobe with 5,5 GBq of 90Y-labeled glass microspheres. It was followed by extended right hepatectomy after preparation by embolization of the right portal and the right hepatic veins. Thirty months after surgical resection the patient showed neither clinical, radiological nor biological signs of HCC recurrence.DISCUSSION:HCC in non-cirrhotic liver is less common than in cirrhotic liver but has a better prognosis, thanks to a greater opportunity for surgical resection. The symptoms often emerge late and are unspecific, thus delaying the HCC diagnosis. Advances in surgical resection by laparotomy or laparoscopy, and neoadjuvant therapy in preparation for surgery, have proven to be effective. However, high mortality persists due to late diagnosis linked to the inability of identifying groups at risk of HCC in the non-cirrhotic population and inadequate screening.

Purpose Metastatic bone disease (MBD) is the most common form of metastases, most frequently deriving from prostate cancer. MBD is screened with bone scintigraphy (BS), which have high sensitivity but low specificity for the diagnosis of MBD, often requiring further investigations. Deep learning (DL) - a machine learning technique designed to mimic human neuronal interactions- has shown promise in the field of medical imaging analysis for different purposes, including segmentation and classification of lesions. In this study, we aim to develop a DL algorithm that can classify areas of increased uptake on bone scintigraphy scans. Methods We collected 2365 BS from three European medical centres. The model was trained and validated on 1203 and 164 BS scans respectively. Furthermore we evaluated its performance on an external testing set composed of 998 BS scans. We further aimed to enhance the explainability of our developed algorithm, using activation maps. We compared the performance of our algorithm to that of 6 nuclear medicine physicians. Results The developed DL based algorithm is able to detect MBD on BSs, with high specificity and sensitivity (0.80 and 0.82 respectively on the external test set), in a shorter time compared to the nuclear medicine physicians (2.5 min for AI and 30 min for nuclear medicine physicians to classify 134 BSs). Further prospective validation is required before the algorithm can be used in the clinic.

Introduction[18F]FDG PET/CT noninvasively disproves acute kidney allograft rejection (AR) in kidney transplant recipients (KTRs) with suspected AR. However, the correlation of biopsy-based Banff vs. PET/CT-based scores of acute inflammation remains unknown, as does the prognostic performance of [18F]FDG PET/CT at one year post suspected AR.MethodsFrom 2012 to 2019, 114 [18F]FDG-PET/CTs were prospectively performed in 105 adult KTRs who underwent per cause transplant biopsies. Ordinal logistic regression assessed the correlation between the extent of histological inflammation and the mean standardized [18F]FDG uptake values (mSUVmean). Functional outcomes of kidney allografts were evaluated at one year post per cause biopsy and correlated to mSUVmean.ResultsA significant correlation between mSUVmean and acute Banff score was found, with an adjusted R2 of 0.25. The mSUVmean was significantly different between subgroups of “total i”, with 2.30 ± 0.71 in score 3 vs. 1.68 ± 0.24 in score 0. Neither the function nor the survival of the graft at one year was statistically related to mSUVmean.Discussion[18F]FDG-PET/CT may help noninvasively assess the severity of kidney allograft inflammation in KTRs with suspected AR, but it does not predict graft outcomes at one year.

Sarcoidosis and lymphoma often share common features on 18F-FDG PET/CT, such as intense hypermetabolic lesions in lymph nodes and multiple organs. We aimed at developing and validating radiomics signatures to differentiate sarcoidosis from Hodgkin lymphoma (HL) and diffuse large B-cell lymphoma (DLBCL). Methods: We retrospectively collected 420 patients (169 sarcoidosis, 140 HL, and 111 DLBCL) who underwent pretreatment 18F-FDG PET/CT at the University Hospital of Liege. The studies were randomly distributed to 4 physicians, who gave their diagnostic suggestion among the 3 diseases. The individual and pooled performance of the physicians was then calculated. Interobserver variability was evaluated using a sample of 34 studies interpreted by all physicians. Volumes of interest were delineated over the lesions and the liver using MIM software, and 215 radiomics features were extracted using the RadiomiX Toolbox. Models were developed combining clinical data (age, sex, and weight) and radiomics (original and tumor-to-liver TLR radiomics), with 7 different feature selection approaches and 4 different machine-learning (ML) classifiers, to differentiate sarcoidosis and lymphomas on both lesion-based and patient-based approaches. Results: For identifying lymphoma versus sarcoidosis, physicians' pooled sensitivity, specificity, area under the receiver-operating-characteristic curve (AUC), and accuracy were 0.99 (95% CI, 0.97-1.00), 0.75 (95% CI, 0.68-0.81), 0.87 (95% CI, 0.84-0.90), and 89.3%, respectively, whereas for identifying HL in the tumor population, it was 0.58 (95% CI, 0.49-0.66), 0.82 (95% CI, 0.74-0.89), 0.70 (95% CI, 0.64-0.75) and 68.5%, respectively. Moderate agreement was found among observers for the diagnosis of lymphoma versus sarcoidosis and HL versus DLBCL, with Fleiss κ-values of 0.66 (95% CI, 0.45-0.87) and 0.69 (95% CI, 0.45-0.93), respectively. The best ML models for identifying lymphoma versus sarcoidosis showed an AUC of 0.94 (95% CI, 0.93-0.95) and 0.85 (95% CI, 0.82-0.88) in lesion- and patient-based approaches, respectively, using TLR radiomics (plus age for the second). To differentiate HL from DLBCL, we obtained an AUC of 0.95 (95% CI, 0.93-0.96) in the lesion-based approach using TLR radiomics and 0.86 (95% CI, 0.80-0.91) in the patient-based approach using original radiomics and age. Conclusion: Characterization of sarcoidosis and lymphoma lesions is feasible using ML and radiomics, with very good to excellent performance, equivalent to or better than that of physicians, who showed significant interobserver variability in their assessment.

Introduction. - The toxicity associated with hepatic radioembolization (RE) by microspheres labeled with Yttrium 90 (Y-90) has a very variable incidence between studies and depends on a multitude of parameters. The objective of this study is to assess the various predictive factors of this toxicity, inherent of the patient or the type of procedure. Patients and methods. - Single-center retrospective study including 85 patients with hepatocarcinoma treated by hepatic RE. The medico-technical and clinical-biological parameters were studied over a defined time interval and the toxicity of the latter graded according to the Common Terminology Criteria for Adverse Events. Dosimetry was carried out on the basis of the Y-90 PET/CT using the "Simplicit90Y" software and the statistical analysis using the "SAS" software. Results. - Post-RE hepatotoxicity observed in 77.7% of our population with maximum grade 3 toxicity in 10.6% of cases. The presence post-RE of hyperbilirubinemia and ascites were detected in 32.1% (only grade 1-2) and 27.1% (4.7% grade 3) of patients, respectively. The pre-therapeutic presence of cirrhosis and/or hyperbilirubin are predictive of post-RE toxicity. Other biological elements studied are less relevant in practice. Radioembolization-induced liver disease (REILD) was observed in 15.3% of cases, mainly of moderate form (13.0%). No impact of the dosimetric approach was observed. Conclusion. - A personalized dosimetric approach does not generate additional side effects, while maximizing the tumor dose and therefore the therapeutic effect. The presence of cirrhosis and hyperbilirubinemia pre-RE seem to be the two predominant in the appearance of REILD. (C) 2021 Elsevier Masson SAS. All rights reserved.

In Belgium and around the world, the incidence of primary malignant liver tumours is increasing, both for hepatocarcinoma and cholangiocarcinoma. Their curative treatment is based on multidisciplinary and specialized care, of which surgery (including liver transplantation) remains the cornerstone, often associated with other logoregional treatments, as radioembolisation, radiofrequency ablation, and chemoembolisation. For advanced cases, the prognosis remains poor, in particular due to a certain chemoresistance of these tumours. New treatments include targeted therapies (including various tyrosine kinase inhibitors) and immunotherapy. A specialized multidisciplinary discussion is therefore necessary to define the best therapeutic management, individualized to each patient. In this article, the authors review the most recent data relating to the treatment of hepatocarcinoma and cholangiocarcinoma.

only PG > 1 images were included in the unhealthy database. Using CNN15 to analyse the segmented regions accuracy values ranging between 0.55 in HK (as the lowest) and 1 (as the highest) in H were obtained. Conclusion: This exploratory study of application of CNNs to clinical amyloidosis images showed promising results. Although results are limited due to the small size of the databases used, CNN15 was demonstrated to have good discriminatory ability when classifying images of the segmented heart region of 99m Tc-DPD in amyloidosis patients. CNN27 demonstrated good results in classification of WB images. References: none

Neuroendocrine neoplasms are histologically defined by a common neuroendocrine cellular phenotype. These are still considered as rare tumours even though their incidence is increasing. Heterogeneity is everywhere whether in the localization of the primitive cancer, the clinical presentation, the histological classification, the prognosis, as well as in therapeutic options, which clearly justifies specialized multidisciplinary care. Heterogeneity and scarcity explain the still fragmented nature of knowledge in this domain. Thanks to an increase in incidence, a desire for standardization of classification as well as the arrival of major therapeutic advances, such as vectorized internal radiotherapy, the future of neuroendocrine neoplasia seems more than promising and exciting. In our daily clinical practice at CHU Liège, we hope to bring our stone to the building by listing as many cases as possible in national and/or international databases, by centralizing therapeutic discussions within specific multidisciplinary concertations and by participating in multicenter study protocols.

Purpose [ 18 F]FDG PET/CT (PET/CT) proved useful in the diagnosis of renal and hepatic cyst infection (CyI) in patients with autosomal dominant polycystic kidney disease (ADPKD). However, the definition of CyI by PET/CT is unclear. Here, we characterize the [ 18 F]FDG uptake in CyI in order to infer a visual 4-point diagnostic scale. Methods All ADPKD patients hospitalized between 2007 and 2019 for suspected CyI and who underwent an [ 18 F]FDG PET/CT scan were listed. CyI was defined by 5 concomitant criteria: fever ≥ 38 °C; abdominal pain; peak plasma CRP ≥ 70 mg/L; no other cause of inflammation; and favorable outcomes after antibiotics for ≥ 21 days. First, all PET/CT images were visually interpreted. Next, the [ 18 F]FDG uptake around the suspected CyI was scored using a semiquantitative 4-point scale in comparison to blood and liver activities. Results Sixty [ 18 F]FDG PET/CT scans were performed for suspected CyI in 38 ADPKD patients. Twenty-nine episodes met the gold-standard criteria for CyI. The visual assessment of PET/CT images reached a sensitivity of 73.1% and a specificity of 70.6%. Using the 4-point scale, an [ 18 F]FDG score ≥ 3 (i.e., cyst uptake > liver) improved the specificity to 85.3%. Conclusion [ 18 F]FDG PET-CT is helpful in CyI diagnosis in ADPKD, and the use of a 4-point scoring of [ 18 F]FDG uptake improves its diagnostic yield, with positive and negative predictive values of 78.3 and 78.4%, respectively. External validation is required.

La tomographie par émission de positons (TEP) au [18F]fluoro-deoxy-glucose (FDG) est utile dans le diagnostic de l’infection de kyste (IK) rénal ou hépatique chez les patients atteints d’une polykystose hépato-rénale autosomique dominante (PRAD). Toutefois, la définition TEP d’une IK est floue et subjective. Dans cette étude monocentrique rétrospective observationnelle, nous caractérisons le pattern et l’intensité de l’accumulation du [18F]FDG dans les IK afin de proposer une échelle diagnostique semi-quantitative. Tous les patients PRAD hospitalisés entre 2007 et 2019 pour suspicion d’IK et ayant bénéficié d’une TEP au [18F]FDG ont été identifiés. Une IK était définie par la présence simultanée de 5 critères : fièvre > 38 ° C ; douleur abdominale ; CRP ≥ 70 mg/L ; pas d’autre cause à l’épisode infectieux ; et évolution favorable après une antibiothérapie d’au moins 21 jours. Initialement, les images de TEP au [18F]FDG ont été interprétées de façon conventionnelle. Ensuite, l’intensité de l’uptake de [18F]FDG autour du kyste suspect a été quantifiée en utilisant une échelle à 4 grades comparant l’intensité observée à celle du foie et du pool sanguin. Soixante TEP au [18F]FDG ont été réalisées chez 38 patients. Vingt-neuf épisodes correspondaient aux critères d’IK. L’interprétation conventionnelle de la TEP au [18F]FDG aboutissaient à une sensibilité de 73,1 % et une spécificité de 70,6 %. En appliquant l’échelle visuelle de 4 grades, la spécificité augmentait à 85,3 % en considérant le seuil diagnostique d’un signal kystique ≥ 3 (c.-à-d. un uptake kystique supérieur à l’activité basale du foie). En conclusion, la TEP au [18F]FDG est utile dans le diagnostic d’IK chez le patient PRAD. De plus, l’utilisation d’une échelle visuelle semi-quantitative permet d’améliorer sa performance diagnostique, avec des valeurs prédictives positives et négatives respectivement de 78,3 et 78,4 %.

Abstract Introduction Strong correlation has been demonstrated between tumor dose and response and between healthy liver dose and side effects. Individualized dosimetry is increasingly recommended in the current clinical routine. However, hepatic and tumor segmentations could be complex in some cases. The aim of this study is to assess the reproducibility of the tumoral and non-tumoral liver dosimetry in selective internal radiation therapy (SIRT). Material and methods Twenty-three patients with hepatocellular carcinoma (HCC) who underwent SIRT with glass microspheres were retrospectively included in the study. Tumor (TV) and total liver volumes (TLV), and mean absorbed doses in tumoral liver (TD) and non-tumoral liver (THLD) were determined on the 90Y PET/CT studies using Simplicit90YTM software, by three independent observers. Dosimetry datasets were obtained by a medical physicist helped by a nuclear medicine (NM) physician with 10 years of experience (A), by a NM physician with 4-year experience (B), and by a resident who first performed 10 dosimetry assessments as a training (C). Inter-observer agreement was evaluated using intra-class correlation coefficients (ICC), coefficients of variation (CV), Bland-Altman plots, and reproducibility coefficient (RDC). Results A strong agreement was observed between all three readers for estimating TLV (ICC 0.98) and THLD (ICC 0.97). Agreement was lower for TV delineation (ICC 0.94) and particularly for TD (ICC 0.73), especially for the highest values. Regarding TD, the CV (%) was 26.5, 26.9, and 20.2 between observers A and B, A and C, and B and C, respectively, and the RDC was 1.5. Regarding THLD, it was 8.5, 12.7, and 9.4, and the RDC was 1.3. Conclusion Using a standardized methodology, and regardless of the different experiences of the observers, the estimation of THLD is highly reproducible. Although the reproducibility of the assessment of tumor irradiation is overall quite high, large variations may be observed in a limited number of patients.