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2. Prognostic Value of Multiple Manual Segmentation Methods for Diffuse Large B-Cell Lymphoma with 18F-FDG PET/CTAndrej Doma, Andrej Studen, Barbara Jezeršek Novaković, 2025, original scientific article Abstract: Abstract: Quantitative 18F-FDG PET/CT-derived metabolic metrics are strongly associated with patient outcomes in diffuse large B-cell lymphoma (DLBCL), but the lack of consensus on optimal segmentation thresholds limits standardization. This study evaluated the prognostic value of various metabolic tumor volume (MTV) segmentation approaches in 140 stage II–IV DLBCL patients treated with standard immunochemotherapy. MTV was derived using fixed SUV (≥2.5, ≥4.0), relative (>41% SUVmax), and adaptive (liver-tobackground) thresholds. Baseline MTV metrics significantly correlated with 3-year overall survival (OS3) in univariate analysis in overall cohort, with MTV41 showing the strongest association (HR: 1.27; p = 0.003). MTV25 and MTV41 remained significant in the stage 4 patient subgroup. However, in multivariate analysis, no MTV metric independently predicted OS3 when adjusted for the International Prognostic Index (IPI), which remained the dominant predictor (HR: 1.95; p < 0.0001). ROC analysis confirmed superior AUC for IPI (0.76) over PET-based metrics (0.64–0.69). Predictive models integrating IPI with PET metrics were robust but failed to improve prognostic accuracy beyond IPI alone. Although PET-derived MTV metrics provide prognostic value in univariate analysis, threshold selection has minimal impact, and their added value is limited when combined with IPI, reinforcing its role as the most reliable survival predictor in DLBCL.
Keywords: diffuse large B-cell lymphoma, 18F-FDG, overall survival, PET/CT
Published in DiRROS: 21.11.2025; Views: 240; Downloads: 74
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3. Crayfish pet trade as a pathway for the introduction of known and novel virusesKatarina Bačnik, Luka Kranjc, Leticia Botella, Ivana Maguire, Dora Pavić, Jiří Patoka, Paula Dragičević, Martin Blaha, Ana Bielen, Antonín Kouba, Denis Kutnjak, Sandra Hudina, 2025, original scientific article Abstract: Expanding international pet trade has emerged as one of the main introduction pathways of aquatic invasive species, with ornamental crayfish species commonly available on the EU and global markets. Besides most frequently studied crayfish pathogens, such as Aphanomyces astaci and white spot syndrome virus (WSSV), ornamental crayfish carry associated microbial communities, which may potentially lead to the emergence of known or even novel diseases following intentional or unintentional release of animals into the wild. This is especially problematic in the case of viruses, which represent an important, yet considerably understudied, group of crayfish pathogens. Here we analyzed viromes of hepatopancreas tissue of four crayfish species acquired in the international pet trade in Europe (Procambarus clarkii, Procambarus alleni, Cherax holthuisi, and Cherax quadricarinatus) using a high throughput sequencing based metagenomic approach. Seven different known viruses were identified, which were previously either directly associated with crayfish (WSSV, Cherax quadricarinatus reovirus, chequa iflavirus, athtab bunya-like virus) or with hosts from subphylum Crustacea or invertebrates associated with freshwater environment (Shahe ispoda virus 5, Dicistroviridae sp.). Additional sequences represented 8 potential novel and divergent RNA viruses, most similar to sequences belonging to members of Picornavirales, Elliovirales, Reovirales, Hepelivirales, Tolivirales and Ghabrivirales orders. We discuss our findings in relation to their phylogenetic relationships, geographical origins, and putative pathogenicity implications. The results highlight the need for further research into the risks related to disease emergence associated with the pet trade.
Keywords: virome, RNA viruses, ornamental crayfish, pet-trade, high throughput sequencing, ecology, molecular biology, pathology, virology, environmental risk assessment
Published in DiRROS: 23.05.2025; Views: 820; Downloads: 513
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4. Dynamic balance and gait impairments in Parkinson’s disease : novel cholinergic patternsNicolaas I. Bohnen, Uroš Marušič, Stiven Roytman, Rebecca Paalanen, Fotini Michalakis, Taylor Brown, Peter J. H. Scott, Giulia Carli, Roger Albin, Prabesh Kanel, 2024, original scientific article Abstract: The cholinergic system has been implicated in postural deficits, in particular falls, in Parkinson’s disease.
Falls and freezing of gait typically occur during dynamic and challenging balance and gait conditions,
such as when initiating gait, experiencing postural perturbations, or making turns. However, the precise
cholinergic neural substrate underlying dynamic postural and gait changes remains poorly understood.
The aim of this study was to investigate whether brain vesicular acetylcholine transporter binding, as
measured with [18F]-fluoroethoxybenzovesamicolbinding PET, correlates with dynamic gait and balance
impairments in 125 patients with Parkinson’s disease (mean age 66.89±7.71 years) using the abbreviated
Balance Evaluation Systems Test total and its four functional domain sub-scores (anticipatory postural
control, reactive postural control, dynamic gait, and sensory integration). Whole brain false discoverycorrected (P < 0.05) correlations for total abbreviated Balance Evaluation Systems Test scores included
the following bilateral or asymmetric hemispheric regions: gyrus rectus, orbitofrontal cortex, anterior part
of the dorsomedial prefrontal cortex, dorsolateral prefrontal cortex, cingulum, frontotemporal opercula,
insula, fimbria, right temporal pole, mesiotemporal, parietal and visual cortices, caudate nucleus, lateral
and medial geniculate bodies, thalamus, lingual gyrus, cerebellar hemisphere lobule VI, left cerebellar
crus I, superior cerebellar peduncles, flocculus, and nodulus. No significant correlations were found for
the putamen or anteroventral putamen. The four domain-specific sub-scores demonstrated overlapping
cholinergic topography in the metathalamus, fimbria, thalamus proper, and prefrontal cortices but also
showed distinct topographic variations. For example, reactive postural control functions involved the right
flocculus but not the upper brainstem regions. The anterior cingulum associated with reactive postural
control whereas the posterior cingulum correlated with anticipatory control. The spatial extent of
associated cholinergic system changes were least for dynamic gait and sensory orientation functional
domains compared to the anticipatory and reactive postural control functions. We conclude that specific
aspects of dynamic balance and gait deficits in Parkinson’s disease associate with overlapping but also
distinct patterns of cerebral cholinergic system changes in numerous brain regions. Our study also presents
novel evidence of cholinergic topography involved in dynamic balance and gait in Parkinson’s disease
that have not been typically associated with mobility disturbances, such as the right anterior temporal pole,
right anterior part of the dorsomedial prefrontal cortex, gyrus rectus, fimbria, lingual gyrus, flocculus,
nodulus and right cerebellar hemisphere lobules VI and left crus I.
Keywords: Parkinson’s disease, dynamic balance, cholinergic, PET
Published in DiRROS: 30.08.2024; Views: 1047; Downloads: 1015
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5. Image reconstruction using small-voxel size improves small lesion detection for positron emission tomographySebastijan Rep, Petra Tomše, Luka Jensterle, Leon Jarabek, Katja Zaletel, Luka Ležaič, 2022, original scientific article Abstract: Background. PET/CT imaging is widely used in oncology and provides both metabolic and anatomic information. Because of the relatively poor spatial resolution of PET, the detection of small lesions is limited. The low spatial resolution introduces the partial-volume effect (PVE) which negatively affects images both qualitatively and quantitatively. The aim of the study was to investigate the effect of small-voxel (2 mm in-line pixel size) vs. standard-voxel (4 mm in-line pixel size) reconstruction on lesion detection and image quality in a range of activity ratios. Materials and methods. The National Electrical Manufacturers Association (NEMA) body phantom and the Micro Hollow-Sphere phantom spheres were filled with a solution of [18F]fluorodeoxyglucose ([18F]FDG) in sphere-to-background ratios of 2:1, 3:1, 4:1 and 8:1. In all images reconstructed with 2 mm and 4 mm in-line pixel size the visual lesion delineation, contrast recovery coefficient (CRC) and contrast-to-noise ratio (CNR) were evaluated. Results. For smaller (≤ 13 mm) phantom spheres, significantly higher CRC and CNR using small-voxel reconstructions were found, also improving visual lesion delineation. CRC did not differ significantly for larger (≥ 17 mm) spheres using 2 mm and 4 mm in-line pixel size, but CNR was significantly lower; however, lower CNR did not affect visual lesion delineation. Conclusions. Small-voxel reconstruction consistently improves precise small lesion delineation, lesion contrast and image quality.
Keywords: PET/CT, voxel size, contrast recovery coefficient, contrast-to-noise ratio
Published in DiRROS: 24.07.2024; Views: 964; Downloads: 616
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7. Granulomatosis after autologous stem cell transplantation in nonHodgkin lymphoma : experience of single institution and a review of literatureLučka Boltežar, Ivana Žagar, Barbara Jezeršek Novaković, 2016, review article Abstract: Sarcoidosis before and after treatment of malignancy is an important differential diagnosis that has to be distinguished from lymphoma. Patients and methods. Hodgkin lymphoma, diffuse large B-cell lymphoma and aggressive follicular lymphoma are being staged and treatment effect is evaluated with PET-CT. We report three cases of aggressive lymphoma after high dose therapy and autologous stem cell transplantation with positive lymph nodes on PET-CT, which were histologically diagnosed as sarcoidosis/granulomatosis. In the literature, we found that false positive lymph nodes were more common after allogeneic than after autologous transplantation. Conclusions. Post-treatment PET-CT positive lymph nodes should always be examined histologically prior to any further treatment decision to avoid unnecessary toxic procedures.
Keywords: granulomatosis, nonHodgin lymphoma, PET-CT, differential diagnosis
Published in DiRROS: 30.04.2024; Views: 1399; Downloads: 396
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8. Thyroid lesions incidentally detected by [sup] 18F-FDG PET-CT : a two centre retrospective studyJan Jamšek, Ivana Žagar, Simona Gaberšček, Marko Grmek, 2015, original scientific article Abstract: Incidental 18F-FDG uptake in the thyroid on PET-CT examinations represents a diagnostic challenge. The maximal standardized uptake value (SUVmax) is one possible parameter that can help in distinguishing between benign and malignant thyroid PET lesions. We retrospectively evaluated 18F-FDG PET-CT examinations of 5,911 patients performed at two different medical centres from 2010 to 2011. If pathologically increased activity was accidentally detected in the thyroid, the SUVmax of the thyroid lesion was calculated. Patients with incidental 18F-FDG uptake in the thyroid were instructed to visit a thyroidologist, who performed further investigation including fine needle aspiration cytology (FNAC) if needed. Lesions deemed suspicious after FNAC were referred for surgery. Incidental 18F-FDG uptake in the thyroid was found in 3.89% - in 230 out of 5,911 patients investigated on PET-CT. Malignant thyroid lesions (represented with focal thyroid uptake) were detected in 10 of 66 patients (in 15.2%). In the first medical centre the SUVmax of 36 benign lesions was 5.6 +- 2.8 compared to 15.8 +- 9.2 of 5 malignant lesions (p < 0.001). In the second centre the SUVmax of 20 benign lesions was 3.7 +- 2.2 compared to 5.1 +- 2.3 of 5 malignant lesions (p = 0.217). All 29 further investigated diffuse thyroid lesions were benign. Incidental 18F-FDG uptake in the thyroid was found in 3.89% of patients who had a PET-CT examination. Only focal thyroid uptake represented a malignant lesion in our study - in 15.2% of all focal thyroid lesions. SUVmax should only serve as one of several parameters that alert the clinician on the possibility of thyroid malignancy.
Keywords: thyroid cancer, PET incidentaloma, PET-CT
Published in DiRROS: 22.04.2024; Views: 1299; Downloads: 420
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9. Incidental uptake of 18F-fluorocholine (FCH) in the head or in the neck of patients with prostate cancerMarina Hodolič, Jurij Fettich, 2014, original scientific article Abstract: Background. Positron emission tomography-computed tomography (PET/CT) with 18F-fluorocholine (FCH) is routinely performed in patients with prostate cancer. In this clinical context, foci of FCH uptake in the head or in the neck were considered as incidentalomas, except for those suggestive of multiple bone metastases. Case reports. In 8 patients the incidental focus corresponded to a benign tumour. The standard of truth was histologyin two cases, correlative imaging with MRI in four cases, 99mTc-SestaMIBI scintigraphy, ultrasonography and biochemistry in one case and biochemistry including PTH assay in one case. The final diagnosis of benign tumoursconsisted in 3 pituitary adenomas, 2 meningiomas, 2 hyperfunctioning parathyroid glands and 1 thyroid adenoma. Malignancy was proven histologically in 2 other patients: 1 papillary carcinoma of the thyroid and 1 cerebellar metastasis.Conclusions. To the best of our knowledge, FCH uptake by pituitary adenomas or hyperfunctioning parathyroidglands has never been described previously. We thus discuss whether there might be a future indication for FCH PET/CT when one such tumour is already known or suspected: to detect a residual or recurrent pituitary adenoma aftersurgery, to guide surgery or radiotherapy of a meningioma or to localise a hyperfunctioning parathyroid gland. Inthese potential indications, comparative studies with reference PET tracers or with 99mTc-sestaMIBI in case of hyperparathyroidism could be undertaken.
Keywords: FCH, PET/CT, incidentaloma, meningioma, pituitary adenoma, hyperparathyroidism, thyroid adenoma
Published in DiRROS: 10.04.2024; Views: 1344; Downloads: 366
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10. Consequence of the introduction of routine FCH PET/CT imaging for patients with prostate cancer : a dual centre surveyMarina Hodolič, Laure Michaud, V. Huchet, S. Balogova, V. Nataf, K. Kerrou, M. Vereb, Jurij Fettich, Jean-Noël Talbot, 2014, original scientific article Abstract: Background. Fluorocholine(18F) (FCH) was introduced at the beginning of April 2010 in France, Slovenia and three other EU member states for the localisation of bone metastases of prostate cancer with PET. The aim of the study was to compare the evolution of diagnostic imaging in patients with prostate cancer using a new radiopharmaceutical FCH, observed in France and in Slovenia, and to quantify the consequence of the results of new imaging modality on the detection rate of abnormal metastases and recurrences of prostate cancer.Patients and methods. In two centres (France/Slovenia), a survey of the number of nuclear medicine examinations in patients with prostate cancer was performed, covering 5 quarters of the year since the introduction of FCH. For each examination, the clinical and biological circumstances were recorded, as well as the detection of bone or soft tissue foci.Results. Six hundred and eighty-eight nuclear medicine examinations were performed impatients with prostate cancer. Nuclear medicine examinations were performed for therapy monitoring and follow-up in 23% of cases. The number of FCH PET/CT grew rapidly between the 1st and 5th period of the observation (+220%), while the number of bone scintigraphies (BS) and fluoride(18F) PET/CTs decreased (-42% and -23% respectively). Fluorodeoxyglucose(18F) (FDG) PET/CT remained limited to few cases of castrate-resistant or metastatic prostate cancer in Paris. The proportion of negative results was significantly lower with FCH PET/CT (14%) than with BS (49%) or fluoride(18F) PET/CT (54%). For bone metastases, the detection rate was similar, but FCH PET/CT was performed on average at lower prostate-specific antigen (PSA) levels and was less frequently doubtful (4% vs. 28% for BS). FCH PET/CT also showed foci in prostatic bed (53% of cases) or in soft tissue (35% of cases).Conclusions. A rapid development of FCH PET/CT was observed in both centres and led to a higher detection rate of prostate cancer lesions.
Keywords: prostate cancer, PET/CT, fluorocholine (FCH), fluoride(18F), bone scintigraphy, indication of imaging, prostata, rak (medicina), slikovna diagnostika
Published in DiRROS: 04.04.2024; Views: 1488; Downloads: 1040
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