scholarly journals Optimalisasi Citra Axial Sequence T2 Gradient Echo Dengan Variasi Bandwidth Dan Time Echo Pada MRI Shoulder Untuk Mengurangi Susceptibility Artifacts Dan Chemical Shift

2018 ◽  
Vol 5 (2) ◽  
pp. 40-49
Author(s):  
Akhmad Muzamil ◽  
Nur Vita Indri ◽  
Suryani Dyah Astuti ◽  
Tri Anggono Prijo
Keyword(s):  
Chemical Shift ◽  
Signal To Noise Ratio ◽  
Region Of Interest ◽  
Gradient Echo ◽  
Signal To Noise ◽  
Susceptibility Artifacts ◽  
Axial Gradient ◽  
Noise Ratio ◽  
Mri Shoulder

Penelitian ini bertujuan untuk mengetahui pengaruh Bandwidth (BW) dan Time Echo (TE) pada MRI Shoulder serta mengetahui nilai variasi Bandwidth dan Time Echo yang optimal untuk mengurangi Susceptibility Artifacts dan Chemical Shift. Penelitian ini di lakukan di Rumah Sakit Umum Haji Surabaya dengan menggunakan Pesawat MRI 1,5 Tesla. Penelitian ini  menggunakan varaisi Bandwidth 170 Hz/Px, 190 Hz/Px dan 210 Hz/Px serta menggunakan variasi TE 16 ms dan 20 ms pada pembobotan T2 Medic potongan axial terhadap 4 pasien. Analisa data dilakukan secara kuantitatif dengan menggunakan metode Region of Interest (ROI) pada komputer MRI kemudian dilakukan analisis Signal to Noise Ratio (SNR) dan Contrast to Noise Ratio (CNR) serta analisis terhadap Susceptibility  Artifacts dan Chemical Shift. Variasi Time Echo dan bandwidth berpengaruh signifikan terhadap nilai SNR dan CNR pada hasil citra T2 Axial Gradient Echo MRI Shoulder. Pengaruh kedua variasi tersebut adalah semakin kecil nilai TE dan BW didapatkan SNR yang meningkat. Jika TE diperbesar maka didapatkan CNR yang meningkat. Kualitas citra optimal yang dapat menghasilkan keadaan patologis ditentukan dengan meningkatnya nilai CNR dan nilai artefak yang menurun. Sehingga pada penelitian ini kombinasi antara 2 variabel tersebut dapat menentukan citra optimal pada TE 20ms dan BW 210 Hz/Px.

scholarly journals Optimalisasi Parameter Bandwidth dan Time Echo untuk Mengurangi Susceptibility Artifacts dan Chemical Shift pada MRI

2017 ◽  
Vol 19 (3) ◽  
pp. 237
Author(s):  
Suryani Dyah Astuti ◽  
Nur Vita Indri Astutik ◽  
Akhmad Muzamil
Keyword(s):  
Chemical Shift ◽  
Signal To Noise Ratio ◽  
Region Of Interest ◽  
Gradient Echo ◽  
Signal To Noise ◽  
Susceptibility Artifacts ◽  
Axial Gradient ◽  
Chemical Shift Mri ◽  
Noise Ratio ◽  
Mri Shoulder

AbstrakTelah di lakukan penelitian yang berjudul Optimalisasi Parameter Bandwidth dan Time Echo untuk Mengurangi Susceptibility  Artifacts dan Chemical Shift. Tujuan dari penelitian ini adalah untuk mengetahui pengaruh Bandwidth (BW) dan Time Echo (TE) pada MRI Shoulder serta mengetahui nilai variasi Bandwidth dan Time Echo yang optimal untuk mengurangi Susceptibility  Artifacts dan Chemical Shift. Penelitian ini di lakukan di RSU Haji Surabaya  dengan Pesawat MRI 1,5 Tesla,  parameter Bandwidth 170 Hz/Px, 190 Hz/Px dan 210 Hz/Px dengan  variasi TE 16s dan 20s pada pembobotan T2 Medic potongan axial terhadap 4 pasien. Analisa data dilakukan secara kuantitatif dengan menggunakan metode Region of Interest (ROI) pada komputer MRI kemudian dilakukan analisis Signal to Noise Ratio (SNR) dan Contrast to Noise Ratio (CNR) serta analisis terhadap Susceptibility  Artifacts dan Chemical Shift. Variasi Time Echo dan bandwidth berpengaruh signifikan terhadap nilai SNR dan CNR pada hasil citra T2 Axial Gradient Echo MRI Shoulder. Pengaruh kedua variasi tersebut adalah semakin kecil nilai TE dan BW didapatkan SNR yang meningkat. Jika TE diperbesar maka didapatkan CNR yang meningkat. Kualitas citra optimal yang dapat menghasilkan keadaan patologis ditentukan dengan meningkatnya nilai CNR dan nilai artefak yang menurun. Sehingga Pada penelitian ini kombinasi antara 2 variabel tersebut dapat menentukan citra optimal pada TE 20ms dan BW 210 Hz/Px. Kata Kunci: Bandwidth, TE, Susceptibility Artifacts, Chemical Shift, MRI Shoulder

The Influence of Alteration of kVp and mAs towards the Image Quality of Acrylic Using CBCT

2019 ◽  
Vol 829 ◽  
pp. 252-257
Author(s):  
Azhari ◽  
Yohanes Hutasoit ◽  
Freddy Haryanto
Keyword(s):  
Image Quality ◽  
Signal To Noise Ratio ◽  
Region Of Interest ◽  
Signal To Noise ◽  
Bite Block ◽  
Significant Difference ◽  
Noise Ratio ◽  
Post Hoc ◽  
Radiograph Image

CBCT is a modernized technology in producing radiograph image on dentistry. The image quality excellence is very important for clinicians to interpret the image, so the result of diagnosis produced becoming more accurate, appropriate, thus minimizing the working time. This research was aimed to assess the image quality using the blank acrylic phantom polymethylmethacrylate (PMMA) (C­5H8O2)n in the density of 1.185 g/cm3 for evaluating the homogeneity and uniformity of the image produced. Acrylic phantom was supported with a tripod and laid down on the chin rest of the CBCT device, then the phantom was fixed, and the edge of the phantom was touched by the bite block. Furthermore, the exposure of the X-ray was executed toward the acrylic phantom with various kVp and mAs, from 80 until 90, with the range of 5 kV and the variation of mA was 3, 5, and 7 mA respectively. The time exposure was kept constant for 25 seconds. The samples were taken from CBCT acrylic images, then as much as 5 ROIs (Region of Interest) was chosen to be analyzed. The ROIs determination was analyzed by using the ImageJ® software for recognizing the influence of kVp and mAs towards the image uniformity, noise and SNR. The lowest kVp and mAs had the result of uniformity value, homogeneity and signal to noise ratio of 11.22; 40.35; and 5.96 respectively. Meanwhile, the highest kVp and mAs had uniformity value, homogeneity and signal to noise ratio of 16.96; 26.20; and 5.95 respectively. There were significant differences between the image uniformity and homogeneity on the lowest kVp and mAs compared to the highest kVp and mAs, as analyzed with the ANOVA statistics analysis continued with the t-student post-hoc test with α = 0.05. However, there was no significant difference in SNR as analyzed with the ANOVA statistic analysis. The usage of the higher kVp and mAs caused the improvement of the image homogeneity and uniformity compared to the lower kVp and mAs.

k-Space filtering in 2D gradient-echo breath-hold hyperpolarized3He MRI: Spatial resolution and signal-to-noise ratio considerations

2002 ◽  
Vol 47 (4) ◽  
pp. 687-695 ◽  
Author(s):  
Jim M. Wild ◽  
Martyn N.J. Paley ◽  
Magalie Viallon ◽  
Wolfgang G. Schreiber ◽  
Edwin J.R. van Beek ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Signal To Noise Ratio ◽  
Breath Hold ◽  
Gradient Echo ◽  
Signal To Noise ◽  
Noise Ratio

An optimized method for NMR-based plant seed metabolomic analysis with maximized polar metabolite extraction efficiency, signal-to-noise ratio, and chemical shift consistency

The Analyst ◽  
2014 ◽  
Vol 139 (7) ◽  
pp. 1769-1778 ◽  
Author(s):  
Xiangyu Wu ◽  
Ning Li ◽  
Hongde Li ◽  
Huiru Tang
Keyword(s):  
Chemical Shift ◽  
Extraction Efficiency ◽  
Signal To Noise Ratio ◽  
Metabolomic Analysis ◽  
Signal To Noise ◽  
Plant Seed ◽  
Polar Metabolite ◽  
Extraction Solvent ◽  
Noise Ratio ◽  
Metabolite Extraction

An optimized method for NMR-based plant seed metabolomic analysis was established with extraction solvent, cell-breaking method and extract-to-buffer ratio.

scholarly journals PERBANDINGAN METODE UNTUK PERBAIKAN KUALITAS CITRA MAMMOGRAM

2016 ◽  
Vol 7 (2) ◽  
pp. 657
Author(s):  
Hanifah Rahmi Fajrin
Keyword(s):  
Mean Square Error ◽  
Signal To Noise Ratio ◽  
Median Filter ◽  
Region Of Interest ◽  
Contourlet Transform ◽  
Mean Square ◽  
Signal To Noise ◽  
Noise Ratio

Kanker payudara merupakan pembunuh nomor satu pada wanita di seluruh dunia. Sejauh ini, deteksi dari kanker payudara hanya menggunakan mata telanjang dan berdasarkan jam terbang (pengalaman) dari dokter dan radiologis. Terdapat beberapa kelemahan dalam menganalisis mammogram payudara guna mendeteksi keberadaan kanker payudara. Hal ini bisa diakibatkan oleh sel kanker yang tertutup oleh noise, kontras citra yang rendah dan faktor manusiawi lainnya seperti : kelelahan, mood, dan lainnya. Untuk meminimalisir hal tersebut dibutuhkan suatu metode yang dapat membantu dokter dalam menganalisis citra mammogram payudara. Pada penelitian ini, dilakukan suatu proses yang bertujuan untuk meningkatkan kualitas mammogram agar lebih memudahkan dokter dalam mendiagnosis kelainan pada payudara. Citra yang diolah merupakan citra mammogram yang tidak dipangkas dan tidak disegmentasi pada bagian Region of Interest (ROI), melainkan keseluruhan citra payudara setelah dihilangkan background yang berlebihan. Tahapan pada proses peningkatan kuliatas citra mammogram ini (pra pengolahan) terdiri dari : menghilangkan label atau artifak yang ditemukan pada mammogram, meng-crop citra pada bagian payudara saja (menghilangkan background), memperbaiki kontras citra dengan membandingkan beberapa metode yaitu: CLAHE, Non Subsampled Contourlet Transform (NSCT), Contras Stretching (CS) dan selanjutnya dilakukan smoothing dengan menggunakan filter median. Kinerja dari setiap metode dihitung dengan mencari nilai Mean Square Error (MSE) dan Peak Signal to Noise Ratio (PSNR) citra. Dari nilai MSE dan PSNR yang didapatkan, ditemukan nilai MSE dan PSNR terbaik pada metode NSCT dengan nilai 50.20878 db 31.75332 db. Kata kunci: CLAHE, NSCT, CS, median filter.

Low Flip Angle Gradient Echo Magnetic Resonance Imaging of the Cervical Spine at 0.3 Tesla

1989 ◽  
Vol 30 (4) ◽  
pp. 343-348 ◽  
Author(s):  
S. Holtås ◽  
F. Ståhlberg ◽  
H. Nilsson ◽  
E.-M. Larsson ◽  
A. Ericsson
Keyword(s):  
Cervical Spine ◽  
Signal To Noise Ratio ◽  
Spin Echo ◽  
Flip Angle ◽  
Acquisition Time ◽  
Gradient Echo ◽  
Signal To Noise ◽  
Spine Imaging ◽  
Spin Echo Sequence ◽  
Noise Ratio

The influence of flip angle and TR on signal to noise ratio and contrast between cerebrospinal fluid (CSF) and cord was evaluated in cervical spine imaging in 5 volunteers, using gradient echo technique. All experiments were performed on a 0.3 tesla Fonar β-3000 M scanner using solenoidal surface coils. The most useful sequence was considered to be TR/TE=300/12 ms and 10° flip angle. This sequence provided images with a ‘myelographic appearance’ with good delineation of cord, CSF and epidural space. The grey and white matter was also regularly visualized. The acquisition time was considerably shorter than would have been necessary if a long TR/TE spin echo sequence had been used to obtain the same contrast pattern and the sequence was not as sensitive to motion as was the spin echo sequence. The sequence was also evaluated in 10 patients with degenerative disease and in 5 with lesions in the cord. The gradient echo sequence was found to be equal to or better than short and long TR/TE spin echo sequences in demonstrating narrowing of the spinal canal and cord lesions. The drawback is the limited signal to noise ratio.

Influence of region-of-interest determination on measurement of signal-to-noise ratio in liver on PET images

2017 ◽  
Vol 32 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Shinji Amakusa ◽  
Koki Matsuoka ◽  
Masayuki Kawano ◽  
Kiyotaka Hasegawa ◽  
Mio Ouchida ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Region Of Interest ◽  
Signal To Noise ◽  
Noise Ratio

scholarly journals Háromdimenziós, gyors, kétfoton-pásztázó eljárások sejt- és hálózatszintű idegsejtvizsgálatokhoz

2015 ◽  
Vol 156 (52) ◽  
pp. 2120-2126
Author(s):  
Gergely Szalay ◽  
Linda Judák ◽  
Zoltán Szadai ◽  
Balázs Chiovini ◽  
Dávid Mezey ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Activity Patterns ◽  
Random Access ◽  
Region Of Interest ◽  
High Signal ◽  
Signal To Noise ◽  
Two Photon ◽  
Multiple Line ◽  
Multiple Regions ◽  
Noise Ratio

Introduction: Two-photon microscopy is the ideal tool to study how signals are processed in the functional brain tissue. However, early raster scanning strategies were inadequate to record fast 3D events like action potentials. Aim: The aim of the authors was to record various neuronal activity patterns with high signal-to-noise ratio in an optical manner. Method: Authors developed new data acquisition methods and microscope hardware. Results: Multiple Line Scanning enables the experimenter to select multiple regions of interests, doing this not just increases repetition speed, but also the signal-to-noise ratio of the fluorescence transients. On the same principle, an acousto-optical deflector based 3D scanning microscope has been developed with a sub-millisecond temporal resolution and a millimeter z-scanning range. Its usability is demonstrated by obtaining 3D optical recordings of action potential backpropagation in several hundred micrometers long neuronal processes of single neurons and by 3D random-access scanning of Ca2+ transients in hundreds of neurons in the mouse visual cortex. Conclusions: Region of interest scanning enables high signal-to-noise ratio and repetition speed, while keeping good depth penetration of the two-photon microscopes. Orv. Hetil., 2015, 156(52), 2120–2126.

Sign in / Sign up

Export Citation Format

Share Document