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- Petruson, Karin, 1967, et al.
(författare)
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Nitric oxide production in the sphenoidal sinus by the inducible and constitutive isozymes of nitric oxide synthase
- 2005
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Ingår i: Rhinology. - 0300-0729. ; 43:1, s. 18-23
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To study the production of nitric oxide (NO), and the presence of different isoforms of the NO-synthesising enzyme, NO-synthase (NOS), in the paranasal sinus. MATERIALS AND METHODS: Ten patients, undergoing surgery for pituitary adenoma, were examined for the presence of NO gas in the sphenoidal and maxillary sinus. The distribution of different NOS isozymes in mucosal biopsies from sphenoid and maxillary sinus and ethmoidal cells was studied. RESULTS: The mean concentration of NO was 2575 ppb in the sphenoidal sinus and 6792 ppb in the maxillary sinus. Morphological analyses revealed intense NADPH-diaphorase staining throughout the epithelium. Immunoreactivity against NOS2 (inducible NOS) was observed in the apical cell layer but not of the basal layer. NOS1 (neuronal NOS)-immunoreactivity was mainly seen in the subapical part of the epithelium and NOS3 (endothelial NOS)-immunoreactivity was observed only in the most apical part of the epithelium. CONCLUSION: NO concentration in the sphenoidal sinus is about the same as in the nasal cavity and approximately half of the concentration found in the maxillary sinus. All of the three main different isozymes of NOS can be demonstrated in the mucosa of the sphenoidal and maxillary sinus and ethmoidal cells, NOS2 being the most abundant isoform.
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| 3. |
- Petruson, Karin, 1967, et al.
(författare)
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Juvenile nasopharyngeal angiofibroma: long-term results in preoperative embolized and non-embolized patients.
- 2002
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Ingår i: Acta oto-laryngologica. - 0001-6489. ; 122:1, s. 96-100
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Tidskriftsartikel (refereegranskat)abstract
- A treatment and follow-up study of 32 patients with juvenile nasopharyngeal angiofibroma (JNA) was performed at our clinic between 1974 and 1998. The majority had undergone surgery either via an antral approach or with a lateral rhinotomy. In the 1970s, surgery was combined with ligature of the external carotid artery and, since 1981, it has been combined with preoperative embolization. Two patients received radiotherapy (45 Gy) as primary treatment and the 3 cases of multiple recurrence received radiotherapy (30-45 Gy) as secondary treatment. No recurrence was found in patients treated with radiotherapy. The overall recurrence rate was 25%; the recurrence rate in non-embolized patients was 8% and among embolized patients it was 41%. We found no statistically verified differences in recurrence rate between embolized and non-embolized patients. No statistically significant difference was found in either recurrence or peroperative bleeding when comparing preoperatively embolized patients with non-embolized patients. Regression analyses showed that the only factor affecting recurrence was age, i.e. the younger the patient was at diagnosis the greater the risk of developing recurrence. The development of imaging and embolization techniques will hopefully contribute in the future towards reducing the recurrence rate.
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| 5. |
- Fernström, Erik, et al.
(författare)
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Results of preoperative chemoradiotherapy for patients with advanced cancer of the nasal cavity and paranasal sinuses.
- 2017
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Ingår i: Acta oto-laryngologica. - : Informa UK Limited. - 1651-2251 .- 0001-6489. ; 137:12, s. 1292-1300
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Tidskriftsartikel (refereegranskat)abstract
- Curative treatment of nasal cavity and paranasal sinus cancer is challenging due to the proximity to critical anatomical structures. The purpose of this study was to analyze the impact of trimodality therapy with preoperative chemotherapy and reduced-dose radiotherapy followed by organ-preserving surgery for treating patients with nasal cavity and paranasal sinus cancer.This retrospective study included all 156 patients diagnosed with sinonasal cancer in western Sweden between 1986 and 2009. We determined the treatment selection pattern and treatment outcomes for 79 patients treated with preoperative chemoradiotherapy.Squamous cell carcinoma was the most common histology. The five-year overall survival was 54%, and 85% of these patients had T3 or T4 tumors. The five-year cumulative incidence rate of local recurrence was 32%. The five-year overall survival in patients with squamous cell carcinoma and adenocarcinoma was 45% and 76%, respectively. The median preoperative radiation dose was 48Gy. Orbital exenteration was performed in 7% of patients.Preoperative chemoradiotherapy may be beneficial for patients with advanced sinonasal cancer when primary radical surgery is challenging. Survival outcomes were comparable to outcomes reported in the literature despite conservative surgery and relatively low radiation doses in patients with locally advanced tumors.
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| 8. |
- Palmér, Emilia, 1993, et al.
(författare)
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Estimation and visualization of geometric fidelity using geometric offset maps for improved guidance in H&N radiation therapy
- 2022
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Ingår i: Annual Meeting ISMRM (International Society of Magnetic Resonance in Medicine).
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Konferensbidrag (refereegranskat)abstract
- n an MRI-only workflow, high geometric fidelity of the MRI data is required. Head and neck (H&N) cancer patients, however, frequently have implants, e.g., dental restorations, causing distortions of the MRI data. Geometric offset maps were computed using B0-map calculated from the Dixon-sequence included in the standard clinical protocol. Even though the implants included in this pre-study did not contribute with a significant geometric offset in the delineated target volume, visualization of the geometric offset maps as such bring additional important information when delineating structures in an MRI-only H&N workflow and could thereby become a promising tool in clinical practice.
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| 9. |
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| 10. |
- Palmér, Emilia, 1993, et al.
(författare)
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Head and neck cancer patient positioning using synthetic CT data in MRI-only radiation therapy.
- 2022
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Ingår i: Journal of applied clinical medical physics. - : Wiley. - 1526-9914. ; 23:4
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Tidskriftsartikel (refereegranskat)abstract
- The accuracy and precision of patient positioning is crucial in radiotherapy; however, there are no publications available using synthetic computed tomography (sCT) that evaluate rotations in head and neck (H&N) patients positioning or the effect of translation and rotation combined. The aim of this work was to evaluate the differences between using sCT with the CT for 2D- and 3D-patient positioning in a magnetic resonance imaging (MRI)-only workflow.This study included 14 H&N cancer patients, with generated sCT data (MRI Planner v2.2) and the CT deformably registered to the MRI. Patient positioning was evaluated by comparing sCT against CT data: 3D cone beam CT (CBCT) was registered to the deformed CT (dCT) and sCT in six degrees of freedom (DoF) with a rigid auto-registration algorithm and bone threshold, and 2D deformed digital reconstructed radiographs (dDRR) and synthetic DRRs (sDRR) were manually registered to orthogonal projections in five DoF by six blinded observers. The difference in displacement in all DoF were calculated for dCT and sCT, as well as for dDRR and sDRR. The interobserver variation was evaluated by separate application of the paired dDRR and sDRR registration matrices to the original coordinates of the planning target volume (PTV) structures and calculation of the Euclidean distance between the corresponding points. The Dice similarity coefficient (DSC) was calculated between dDRR/sDRR-registered PTVs.The mean difference in patient positioning using CBCT was<0.7mm and<0.3° and using orthogonal projections<0.4mm and<0.2° in all directions. The maximum Euclidean distance was 5.1mm, the corresponding mean (1SD) Euclidean distance and mean DSC were 3.5 ± 0.7mm and 0.93, respectively.This study shows that the sCT-based patient positioning gives a comparable result with that based on CT images, allowing sCT to replace CT as reference for patient treatment positioning.
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| 11. |
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| 12. |
- Palmér, Emilia, 1993, et al.
(författare)
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Synthetic computed tomography data allows for accurate absorbed dose calculations in a magnetic resonance imaging only workflow for head and neck radiotherapy
- 2021
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Ingår i: Physics and Imaging in Radiation Oncology. - : Elsevier BV. - 2405-6316. ; 17, s. 36-42
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Tidskriftsartikel (refereegranskat)abstract
- Background and purpose: Few studies on magnetic resonance imaging (MRI) only head and neck radiation treatment planning exist, and none using a generally available software. The aim of this study was to evaluate the accuracy of absorbed dose for head and neck synthetic computed tomography data (sCT) generated by a commercial convolutional neural network-based algorithm. Materials and methods: For 44 head and neck cancer patients, sCT were generated and the geometry was validated against computed tomography data (CT). The clinical CT based treatment plan was transferred to the sCT and recalculated without re-optimization, and differences in relative absorbed dose were determined for dose-volume-histogram (DVH) parameters and the 3D volume. Results: For overall body, the results of the geometric validation were (Mean ± 1sd): Mean error −5 ± 10 HU, mean absolute error 67 ± 14 HU, Dice similarity coefficient 0.98 ± 0.05, and Hausdorff distance difference 4.2 ± 1.7 mm. Water equivalent depth difference for region Th1-C7, mid mandible and mid nose were −0.3 ± 3.4, 1.1 ± 2.0 and 0.7 ± 3.8 mm respectively. The maximum mean deviation in absorbed dose for all DVH parameters was 0.30% (0.12 Gy). The absorbed doses were considered equivalent (p-value < 0.001) and the mean 3D gamma passing rate was 99.4 (range: 95.7–99.9%). Conclusions: The convolutional neural network-based algorithm generates sCT which allows for accurate absorbed dose calculations for MRI-only head and neck radiation treatment planning. The sCT allows for statistically equivalent absorbed dose calculations compared to CT based radiotherapy.
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| 16. |
- Pettersson, Erik, 1987, et al.
(författare)
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Structure delineation in the presence of metal - A comparative phantom study using single and dual-energy computed tomography with and without metal artefact reduction
- 2019
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Ingår i: Physics and Imaging in Radiation Oncology. - : Elsevier BV. - 2405-6316. ; 9, s. 43-49
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Tidskriftsartikel (refereegranskat)abstract
- Background and purpose: Metal artefacts in computed tomography (CT) images impairs structure delineation. These artefacts can potentially be reduced with dual-energy CT (DECT) with or without using metal artefact reduction (MAR). The purpose was to investigate how structure delineation in DECT with or without MAR and single-energy CT (SECT) images were affected by metals. Materials and methods: A phantom with known irregular structures was developed. References tructures were determined from a low-noise scan without metal. Bilateral hip prostheses were simulated with steel or titanium inserts. The phantom was scanned with SECT and fast-kV switching DECT with optional MAR. Four radiation oncologists delineated the structures in two phantom set-ups. Delineated structures were evaluated with Dice similarity coefficient (DSC) and Hausdorff distance relative to the reference structures. Results: With titanium inserts, more structures were detected for non-MAR DECT compared to SECT while the same or less were detected with steel inserts. MAR improved delineation in DECT images. For steel inserts, Three structures in the region of artefacts, were delineated by at least two oncologists with MAR-DECT compared to none with non-MAR DECT or SECT. The highest values of DSC for MAR-DECT were 0.69, 0.81 and 0.77 for those structures. Conclusions: Delineation was improved with non-MAR DECT compared to SECT, especially for titanium inserts. A larger improvement was seen with the use of MAR for both steel and titanium inserts. The improvement was dependent on the location of the structure relative to the inserts, and the structure contrast relative to the background.
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| 17. |
- Romlin, Birgitta S, et al.
(författare)
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Moderate superficial hypothermia prolongs bleeding time in humans.
- 2007
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Ingår i: Acta anaesthesiologica Scandinavica. - : Wiley. - 0001-5172 .- 1399-6576. ; 51:2, s. 198-201
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: In vitro and in vivo studies have shown that mild systemic hypothermia influences platelet adhesion and aggregation and coagulation reactions. We wanted to test the hypothesis that mild local hypothermia in healthy volunteers with preserved core temperature increased bleeding time. A secondary aim was to evaluate if local cooling influenced whole blood coagulation measured by thrombelastograph (TEG) in the same setting. METHODS: Bleeding time was measured at the left volar forearm at a baseline skin temperature of 32 degrees C and after cooling to 30 degrees C and 28 degrees C in a water bath. Skin temperature was continuously measured by contact thermistors. Measurements of coagulation by TEG were performed at baseline skin temperature before cooling and after cooling to 28 degrees C skin temperature. Tympanic membrane temperature was continuously measured. RESULTS: Compared with baseline, bleeding time was significantly prolonged at 30 degrees C skin temperature and further prolonged at 28 degrees C skin temperature. No significant differences were measured in any of the TEG parameters. During the procedure, tympanic membrane temperature did not change. CONCLUSION: Lowering the skin temperature from 32 degrees C to 30 degrees C and 28 degrees C with a preserved core temperature more than doubled the bleeding time. Whole blood coagulation measured by TEG was not influenced by the local cooling. In addition to core temperature, local temperature may offer information in understanding the surgical site of bleeding.
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