Related Experiment Video
Updated: Jan 31, 2026

Determining the Likelihood of Variant Pathogenicity Using Amino Acid-level Signal-to-Noise Analysis of Genetic Variation
Published on: January 16, 2019
Fast Padé transform for increasing the signal to noise ratio of spectra provided by STEAM pulse sequence
Mahdi Saeedi-Moghadam1, Majid Pouladian2,3, Reza Faghihi4,5
1Department of Medical Radiation Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran.
Background/Objective:
There are two routine pulse-sequences for single voxel spectroscopy (SVS), point resolved spectroscopy (PRESS) and stimulated echo acquisition mode (STEAM). Although STEAM has several advantages in comparison to PRESS, signal/noise ratio (SNR) superiority of PRESS makes it the first choice for SVS. Application of fast Padé transform (FPT) instead of Fast Furrier transform (FFT) might increase the SNR of the signal produced by STEAM pulse-sequence and therefore allows the benefits of its advantages. We aimed to evaluate and compare the noise root mean square (RMS) and SNR provided by STEAM pulse-sequence using both FPT and FFT.
Materials And Method:
A gelatin-based phantom was constructed in a 19-cm acrylic cylinder. The phantom had two normal/tumoral parts. The SVS was performed using a 3T MRI scanner. STEAM pulse-sequence were used with the following parameters: TR = 2000 ms, TM = 10 ms, and three TEs of 20, 135 and 270 ms with two data-points of 1024 and 512 and voxel-size of 1 cm3. The raw data were extracted and processed using both FFT and FPT estimators to produce the spectrum. The noise RMS and SNR of Cho and Cr metabolites were assessed.
Results:
According to the results, noise RMS of spectra provided by FPT were decreased between 3619.01-14252.94% in comparison to FFT (p< 0.00001). The SNR of Cr1 and Cho peaks of the spectra provided by FPT were increased more than 96.80 and 97.18, respectively (0.00006
Discussion:
The difference of noise RMS's provided by FPT are thousands percent less than FFT. This enormous decrease in noise provides a good increase of SNR. While the range of Cr1 and Cho SNR by FFT are between 41.55-120.32 the range of SNRs of these peaks provided by FPT are between 1719.99-9744.79, which implies a significant difference between the efficiency of FPT and FFT.
Conclusion:
This study showed that application of FPT in comparison to FFT can increase the spectra SNR and so that its usage can be helpful during the application of STEAM pulse-sequence which results in lower SNR in comparison to PRESS pulse-sequence. Thus, we should make use of the advantages of STEAM pulse-sequence.
More Related Videos
Related Concept Videos
Increased pulse rate
Many factors can elevate the risk of developing tachycardia. These include advanced age, a family history of arrhythmias, and an...
Transformers with Off-Nominal Turns Ratios
Fast Fourier Transform
The computational efficiency of the FFT becomes...
NMR Spectrometers: Radiofrequency Pulses and Pulse Sequences
Basic signals of Fourier Transform
The sinc function, defined as sinc(x) = sin(πx)/(πx), is particularly notable for its symmetry and behavior at...
Signal Sequences and Sorting Receptors

