1. Assessment of hyperbaric oxygenation treatment response in parotid glands by T2 mapping following radiotherapy for head and neck tumoursJernej Vidmar, Ksenija Cankar, Maja Grošelj, Žarko Finderle, Igor Serša, 2022, original scientific article Abstract: Background: The study was designed to evaluate the influence of hyperbaric oxygenation therapy (HBOT) on the parotid gland in patients following radiotherapy for head and neck tumours. Patients and methods: HBOT response was monitored by 3T magnetic resonance imaging (MRI) using T 2 mapping and subsequent measurement of mean T 2 and T 2 variability as well as by salivary tests (salivary flow, buffer capacity, and pH). Eighteen patients previously treated with irradiation doses between 50 and 80 Gy as well as 18 healthy gender and age matched controls were enrolled. MRI was performed prior to HBOT (40.2 ± 20 months after radiotherapy) and after 20 daily HBOT at 2.5 ATA (absolute atmosphere). Each HBOT consisted of breathing 100% oxygen for 90 minutes. Results: Significant differences in mean T 2 prior to HBOT were observed between the ipsilateral irradiated (121 ± 20 ms), contralateral parotids (107 ± 21) and control group (96 ± 12 ms). A positive correlation in patients between T 2 variability and irradiation dose was detected in contralateral parotids before HBOT (R = 0.489, p = 0.0287). In addition, negative correlations were observed between mean T 2 in the ipsilateral as well as the contralateral gland and salivary flow before and after HBOT. Negative correlations between mean T 2, T 2 variability and pH of unstimulated saliva were also observed in the sides of parotid before and after HBOT. Conclusions: The study confirmed that T 2 mapping had a potential for monitoring the differences between irradiated and normal parotid glands. It could also be useful in the assessment of the glandular tissue response to HBOT.
Keywords: MRI, T2 mapping, hyperbaric oxygenation therapy, head and neck tumours
Published in DiRROS: 24.07.2024; Views: 133; Downloads: 62
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5. Human tooth pulp anatomy visualization by 3D magnetic resonance microscopyDušan Šušterčič, Igor Serša, 2012, original scientific article Abstract: Background. Precise assessment of dental pulp anatomy is of an extreme importance for a successful endodontic treatment. As standard radiographs of teeth provide very limited information on dental pulp anatomy, more capable methods are highly appreciated. One of these is 3D magnetic resonance (MR) microscopy of which diagnostic capabilities in terms of a better dental pulp anatomy assessment were evaluated in the study. Materials and methods. Twenty extracted human teeth were scanned on a 2.35 T MRI system for MR microscopy using the 3D spin-echo method that enabled image acquisition with isotropic resolution of 100 m. The 3D images were then post processed by ImageJ program(NIH) to obtain advanced volume rendered views of dental pulps. Results. MR microscopy at 2.35 T provided accurate data on dental pulp anatomyin vitro. The data were presented as a sequence of thin 2D slices through the pulp in various orientations or as volume rendered 3D images reconstructed form arbitrary view-points. Sequential 2D images enabled only anapproximate assessment of the pulp, while volume rendered 3D images were more precise in visualization of pulp anatomy and clearly showed pulp diverticles, number of pulp canals and root canal anastomosis. Conclusions. This in vitro study demonstrated that MR microscopy could provide very accurate 3D visualization of dental pulp anatomy. A possible future application of the method in vivo may be of a great importance for the endodontic treatment.
Published in DiRROS: 21.03.2024; Views: 235; Downloads: 92
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6. Study of radiation induced changes of phosphorus metabolism in mice by ▫$^{31}P$▫ NMR spectroscopyIgor Serša, Simona Kranjc Brezar, Gregor Serša, Alenka Nemec Svete, Bojan Ložar, Ana Sepe, Jernej Vidmar, Marjeta Šentjurc, 2010, original scientific article Published in DiRROS: 15.03.2024; Views: 298; Downloads: 98
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9. Uporaba magnetno resonančnega slikanja za raziskave anatomije in vlažnosti lesaMaks Merela, Igor Serša, Urška Mikac, Primož Oven, 2006, original scientific article Abstract: Preverjena je bila uporaba jedrske magnetne resonance (Nmr) za raziskave anatomije in vlažnosti lesa. Na tri metre visoki živi bukvi (Fagus sylvatica L.) smo uporabili 3d spin-echo mr-mikroskopsko tehniko slikanja s prostorsko resolucijo 100 mm in opazovali strukturo odrezane vejice ter spremljali dinamični odziv drevesa na mehansko poškodbo. Za potrditev struktur, vidnih na slikah, smo uporabili svetlobno mikroskopijo. Svetlobna mikroskopija je razkrila anatomsko zgradbo in triletno starost vejice bukve. Slike so jasno razkrile stržen, radialno orientirane večredne ksilemske trakove, traheje ranega lesa, vključno z mejo med ranim in kasnim lesom, kot tudi kambijevo cono s tekočim ksilemskim in floemskim prirastkom. Preučevali smo koncentracijo vode v vejici in globino dehidracije, ki je nastala v 22-tih urah po poškodbi in je segala v globino približno 5 mm od poškodbe. Hitra izguba vlažnosti odseva začetni pasivni odziv prizadetega tkiva. S pomočjo 3d mikroskopije in računalniškega programa Imagej nam je uspelo izdelati prostorski model vode v lesu, ki prikazuje tkiva v vejici z značilno višjo vlažnostjo.
Keywords: MR-mikroskopija, bukev, Fagus sylvatica, živi les, anatomija lesa, vlažnost, porazdelitev vode, mehanska poškodba
Published in DiRROS: 17.11.2020; Views: 1533; Downloads: 463
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10. Dynamic contrast-enhanced MRI of malignant pleural mesothelioma : a comparative study of pharmacokinetic models and correlation with mRECIST criteriaMartina Vivoda Tomšič, Sotirios Bisdas, Viljem Kovač, Igor Serša, Katarina Šurlan Popović, 2019, original scientific article Abstract: BACKGROUND: Malignant pleural mesothelioma (MPM) is a rare and aggressive thoracic malignancy that is difficult to cure. Dynamic contrast-enhanced (DCE) MRI is a functional imaging technique used to analyze tumor microvascular properties and to monitor therapy response. Purpose of this study was to compare two tracer kinetic models, the extended Tofts (ET) and the adiabatic approximation tissue homogeneity model (AATH) for analysis of DCE-MRI and examine the value of the DCE parameters to predict response to chemotherapy in patients with MPM. METHOD: This prospective, longitudinal, single tertiary radiology center study was conducted between October 2013 and July 2015. Patient underwent DCE-MRI studies at three time points: prior to therapy, during and after cisplatin-based chemotherapy. The images were analyzed using ET and AATH models. In short-term follow-up, the patients were classified as having disease control or progressive disease according to modified response evaluation criteria in solid tumors (mRECIST) criteria. Receiver operating characteristic curve analysis was used to examine specificity and sensitivity of DCE parameters for predicting response to therapy. Comparison tests were used to analyze whether derived parameters are interchangeable between the two models. RESULTS: Nineteen patients form the study population. The results indicate that the derived parameters are not interchangeable between the models. Significant correlation with response to therapy was found for AATH-calculated median pre-treatment efflux rate (kep) showing sensitivity of 83% and specificity of 100% (AUC 0.9). ET-calculated maximal pre-treatment kep showed 100% sensitivity and specificity for predicting treatment response during the early phase of the therapy and reached a favorable trend to significant prognostic value post-therapy. CONCLUSION: Both models show potential in predicting response to therapy in MPM. High pre-treatment kep values suggest MPM disease control post-chemotherapy.
Keywords: biomarker, magnetic resonance imaging, mesothelioma, perfusion, response evaluation criteria in solid
tumors, prognosis
Published in DiRROS: 23.09.2020; Views: 1479; Downloads: 1071
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