5 results on '"Kirsi Holli-Helenius"'
Search Results
2. 3D texture analysis reveals imperceptible MRI textural alterations in the thalamus and putamen in progressive myoclonic epilepsy type 1, EPM1.
- Author
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Sanna Suoranta, Kirsi Holli-Helenius, Päivi Koskenkorva, Eini Niskanen, Mervi Könönen, Marja Äikiä, Hannu Eskola, Reetta Kälviäinen, and Ritva Vanninen
- Subjects
Medicine ,Science - Abstract
Progressive myoclonic epilepsy type 1 (EPM1) is an autosomal recessively inherited neurodegenerative disorder characterized by young onset age, myoclonus and tonic-clonic epileptic seizures. At the time of diagnosis, the visual assessment of the brain MRI is usually normal, with no major changes found later. Therefore, we utilized texture analysis (TA) to characterize and classify the underlying properties of the affected brain tissue by means of 3D texture features. Sixteen genetically verified patients with EPM1 and 16 healthy controls were included in the study. TA was performed upon 3D volumes of interest that were placed bilaterally in the thalamus, amygdala, hippocampus, caudate nucleus and putamen. Compared to the healthy controls, EPM1 patients had significant textural differences especially in the thalamus and right putamen. The most significantly differing texture features included parameters that measure the complexity and heterogeneity of the tissue, such as the co-occurrence matrix-based entropy and angular second moment, and also the run-length matrix-based parameters of gray-level non-uniformity, short run emphasis and long run emphasis. This study demonstrates the usability of 3D TA for extracting additional information from MR images. Textural alterations which suggest complex, coarse and heterogeneous appearance were found bilaterally in the thalamus, supporting the previous literature on thalamic pathology in EPM1. The observed putamenal involvement is a novel finding. Our results encourage further studies on the clinical applications, feasibility, reproducibility and reliability of 3D TA.
- Published
- 2013
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3. Association between breast cancer’s prognostic factors and 3D textural features of non-contrast-enhanced T(1) weighted breast MRI
- Author
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Hidemi Okuma, Kirsi Holli-Helenius, Anna Sutela, Mazen Sudah, Anni Lepola, Heikki Junkkari, Otso Arponen, Mervi Könönen, Ritva Vanninen, and Päivi Auvinen
- Subjects
Oncology ,Adult ,medicine.medical_specialty ,Tumour heterogeneity ,Entropy ,Breast Neoplasms ,Kaplan-Meier Estimate ,computer.software_genre ,Disease-Free Survival ,Statistics, Nonparametric ,030218 nuclear medicine & medical imaging ,Correlation ,03 medical and health sciences ,0302 clinical medicine ,Breast cancer ,Imaging, Three-Dimensional ,Voxel ,Internal medicine ,Medicine ,Breast MRI ,Humans ,Radiology, Nuclear Medicine and imaging ,Aged ,Proportional Hazards Models ,Retrospective Studies ,Aged, 80 and over ,medicine.diagnostic_test ,Full Paper ,business.industry ,Proportional hazards model ,Contrast (statistics) ,General Medicine ,Middle Aged ,medicine.disease ,Prognosis ,Magnetic Resonance Imaging ,Tumor Burden ,030220 oncology & carcinogenesis ,Nottingham Prognostic Index ,Female ,Neoplasm Grading ,business ,computer - Abstract
Objectives: The aim of this exploratory study was to evaluate whether three-dimensional texture analysis (3D-TA) features of non-contrast-enhanced T1 weighted MRI associate with traditional prognostic factors and disease-free survival (DFS) of breast cancer. Methods: 3D-T1 weighted images from 78 patients with 81 malignant histopathologically verified breast lesions were retrospectively analysed using standard-size volumes of interest. Grey-level co-occurrence matrix (GLCM)-based features were selected for statistical analysis. In statistics the Mann–Whitney U and the Kruskal–Wallis tests, the Cox proportional hazards model and the Kaplan–Meier method were used. Results: Tumours with higher histological grade were significantly associated with higher contrast (1 voxel: p = 0.033, 2 voxels: p = 0.036). All the entropy parameters showed significant correlation with tumour grade (p = 0.015–0.050) but there were no statistically significant associations between other TA parameters and tumour grade. The Nottingham Prognostic Index (NPI) was correlated with contrast and sum entropy parameters. A higher sum variance TA parameter was a significant predictor of shorter DFS. Conclusion: Texture parameters, assessed by 3D-TA from non-enhanced T1 weighted images, indicate tumour heterogeneity but have limited independent prognostic value. However, they are associated with tumour grade, NPI, and DFS. These parameters could be used as an adjunct to contrast-enhanced TA parameters. Advances in knowledge: 3D-TA of non-contrast enhanced T1 weighted breast MRI associates with tumour grade, NPI, and DFS. The use of non-contrast 3D-TA parameters in adjunct with contrast-enhanced 3D-TA parameters warrants further research.
- Published
- 2021
4. Impact of prone, supine and oblique patient positioning on CBCT image quality, contrast-to-noise ratio and figure of merit value in the maxillofacial region
- Author
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Jorma Järnstedt, Maureen van Eijnatten, Jan Wolff, Kirsi Holli-Helenius, Juha Koivisto, Prasun Dastidar, MKA VUmc (ORM, ACTA), Maxillofacial Surgery (VUmc), Oral and Maxillofacial Surgery / Oral Pathology, and AMS - Trauma and Reconstruction
- Subjects
Scanner ,medicine.medical_specialty ,Supine position ,Image quality ,Patient Positioning ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Contrast-to-noise ratio ,stomatognathic system ,Cadaver ,Prone Position ,Supine Position ,Humans ,Medicine ,Figure of merit ,Radiology, Nuclear Medicine and imaging ,General Dentistry ,business.industry ,Oblique case ,030206 dentistry ,General Medicine ,Cone-Beam Computed Tomography ,Otorhinolaryngology ,Maxilla ,Radiology ,business ,Head ,Research Article - Abstract
Objectives: To assess the impact of supine, prone and oblique patient imaging positions on the image quality, contrast-to-noise ratio (CNR) and figure of merit (FOM) value in the maxillofacial region using a CBCT scanner. Furthermore, the CBCT supine images were compared with supine multislice CT (MSCT) images.Methods: One fresh frozen cadaver head was scanned in prone, supine and oblique imaging positions using a mobile CBCT scanner. MSCT images of the head were acquired in a supine position. Two radiologists graded the CBCT and MSCT images at ten different anatomical sites according to their image quality using a six-point scale. The CNR and FOM values were calculated at two different anatomical sites on the CBCT and MSCT images.Results: The best image quality was achieved in the prone imaging position for sinus, mandible and maxilla, followed by the supine and oblique imaging positions. 12-mA prone images presented high delineation scores for all anatomical landmarks, except for the ear region (carotid canal), which presented adequate to poor delineation scores for all studied head positions and exposure parameters. The MSCT scanner offered similar image qualities to the 7.5-mA supine images acquired using the mobile CBCT scanner. The prone imaging position offered the best CNR and FOM values on the mobile CBCT scanner.Conclusions: Head positioning has an impact on CBCT image quality. The best CBCT image quality can be achieved using the prone and supine imaging positions. The oblique imaging position offers inadequate image quality except in the sinus region.
- Published
- 2017
5. 3D Texture Analysis Reveals Imperceptible MRI Textural Alterations in the Thalamus and Putamen in Progressive Myoclonic Epilepsy Type 1, EPM1
- Author
-
Kirsi Holli-Helenius, Eini Niskanen, Marja Äikiä, Hannu Eskola, Reetta Kälviäinen, Ritva Vanninen, Sanna Suoranta, Mervi Könönen, and Päivi Koskenkorva
- Subjects
Adult ,Male ,Pathology ,medicine.medical_specialty ,Anatomy and Physiology ,Medical Physics ,Adolescent ,Thalamus ,Caudate nucleus ,lcsh:Medicine ,Progressive myoclonus epilepsy ,Amygdala ,Neurological System ,Diagnostic Radiology ,Epilepsy ,Young Adult ,medicine ,Humans ,lcsh:Science ,Child ,Motor Systems ,Multidisciplinary ,medicine.diagnostic_test ,business.industry ,Putamen ,Physics ,lcsh:R ,Magnetic resonance imaging ,Neurodegenerative Diseases ,medicine.disease ,Myoclonic Epilepsies, Progressive ,Magnetic Resonance Imaging ,medicine.anatomical_structure ,Neurology ,Medicine ,lcsh:Q ,Ganglia ,Female ,medicine.symptom ,business ,Radiology ,Myoclonus ,Research Article - Abstract
Progressive myoclonic epilepsy type 1 (EPM1) is an autosomal recessively inherited neurodegenerative disorder characterized by young onset age, myoclonus and tonic-clonic epileptic seizures. At the time of diagnosis, the visual assessment of the brain MRI is usually normal, with no major changes found later. Therefore, we utilized texture analysis (TA) to characterize and classify the underlying properties of the affected brain tissue by means of 3D texture features. Sixteen genetically verified patients with EPM1 and 16 healthy controls were included in the study. TA was performed upon 3D volumes of interest that were placed bilaterally in the thalamus, amygdala, hippocampus, caudate nucleus and putamen. Compared to the healthy controls, EPM1 patients had significant textural differences especially in the thalamus and right putamen. The most significantly differing texture features included parameters that measure the complexity and heterogeneity of the tissue, such as the co-occurrence matrix-based entropy and angular second moment, and also the run-length matrix-based parameters of gray-level non-uniformity, short run emphasis and long run emphasis. This study demonstrates the usability of 3D TA for extracting additional information from MR images. Textural alterations which suggest complex, coarse and heterogeneous appearance were found bilaterally in the thalamus, supporting the previous literature on thalamic pathology in EPM1. The observed putamenal involvement is a novel finding. Our results encourage further studies on the clinical applications, feasibility, reproducibility and reliability of 3D TA.
- Published
- 2013
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