MRI Cervical Image Analysis with Fat Suppression Techniques Between Sequent Turbo Invers Recovery Magnitude (TIRM) and Fat Saturations (Fat Sat) on Degenerative Disc Disease at Haji Hospital Surabaya

This study aimed to analyze the difference of image information and determine the better image quality between the Turbo Invers Recovery Magnitude (TIRM) and Fat Saturation (Fat Sat) techniques on cervical MRI examination at Haji Hospital Surabaya. The samples of this study were one female and three male patients. The obtained data were ROI of the vertebral body tissue, intervertebral discs, spinal cord, and then calculated as SNR and CNR values. SNR and CNR values were statistically tested using Paired T-Test on SPSS 2.5. The Paired T-Test results showed a significant difference between the TIRM and Fat Sat techniques, p>0.05. SNR and CNR average values also proved that the Fat Sat technique had more optimal image quality than the TIRM technique.

Applications of the Dixon technique in the evaluation of the musculoskeletal system

The acquisition of images with suppression of the fat signal is very useful in clinical practice and can be achieved in a variety of sequences. The Dixon technique, unlike other fat suppression techniques, allows the signal of fat to be suppressed in the postprocessing rather than during acquisition, as well as allowing the visualization of maps showing the distribution of water and fat. This review of the Dixon technique aims to illustrate the basic physical principles, to compare the technique with other magnetic resonance imaging sequences for fat suppression or fat quantification, and to describe its applications in the study of diseases of the musculoskeletal system. Many variants of the Dixon technique have been developed, providing more consistent separation of the fat and water signals, as well as allowing correction for many confounding factors. It allows homogeneous fat suppression, being able to be acquired in combination with several other sequences, as well as with different weightings. The technique also makes it possible to obtain images with and without fat suppression from a single acquisition. In addition, the Dixon technique can be used as a quantitative method, allowing the proportion of tissue fat to be determined, and, in more updated versions, can quantify tissue iron.

The Influence of Fat Suppression Technique on Diffusion-weighted (DW) MRI in Lung Cancer

Purpose: To qualitatively and quantitatively investigate the effect of common vendor-related sequence variations in fat suppression techniques on the diagnostic performance of free-breathing DW protocols for lung imaging.Methods: 8 patients with malignant lung lesions were scanned in free breathing using two diffusion-weighted (DW) protocols with different fat suppression techniques: DWA used short-tau inversion recovery (STIR), and DWB used Spectral Adiabatic Inversion Recovery (SPAIR). Both techniques were obtained at two time points, between 1 hour and 1 week apart. Image quality was assessed using a 5-point scoring system. The number of lesions visible within lung, mediastinum and at thoracic inlet on the DW (b=800 s/mm2) images was compared. Signal-to-noise ratios (SNR) were calculated for lesions and para-spinal muscle. Repeatability of ADC values of the lesions was estimated for both protocols together and separately.Results: There was a signal void at the thoracic inlet in all patients with DWB but not with DWA. DWA images were rated significantly better than DWB images overall quality domains. (Cohen’s κ = 1). Although 8 more upper mediastinal/thoracic inlet lymph nodes were detected with DWA than DWB, this did not reach statistical significance (p = 0.23). Tumour ADC values were not significantly different between protocols (p=0.93), their ADC reproducibility was satisfactory (CoV=7.7%) and repeatability of each protocol separately was comparable (CoVDWA=3.7% (95% CI 2.5 – 7.1%) and CoVDWB=4.6% (95% CI 3.1 – 8.8%)).Conclusion: In a free-breathing DW-MRI protocol for lung, STIR fat suppression produced images of better diagnostic quality than SPAIR, while maintaining comparable SNR and providing repeatable quantitative ADC acceptable for use in a multicentre trial setting.

COMPARISON OF VARIOUS MRI FAT SUPPRESSION TECHNIQUES ON A WATER-FAT PHANTOM AT 1.5 T

Nowadays, magnetic resonance imaging (MRI) has been widely applied for diagnosis of soft-tissue diseases. Most clinical MRI protocols use fat suppression (FS) methods to suppress fat signal, reduce chemical shift artifacts, and increase conspicuity of lesions. To understand the advantages, disadvantages, and clinical applications of the most commonly used FS methods is an important issue. The aim of this study was to evaluate FS performance of six FS methods on a fat-water phantom at 1.5[Formula: see text]T. The six MRI methods included iterative decomposition of water and fat with echo asymmetry and least squares estimation (IDEAL), short inversion time inversion recovery (STIR), and four chemical presaturation (Chem Presat) methods. The phantom was composed of homogeneous oil-in-water emulsions with various fat contents ranging from 0 to 100% in increments of 10%. The difference between the suppressed fat fractions (FS fractions) and the true fat fractions of the phantom was used as an index of FS performance. The correlations and levels of agreement (LOAs) between the FS fractions determined using each FS method and the true fat fractions of the phantom were analyzed. From the phantom study, it was found that FSE T2 FS, STIR and IDEAL could achieve more accurate FS fractions than the other three methods. The FS fractions determined using FSE T2 FS, STIR and IDEAL were in a good agreement. On the contrary, T2-weighted spin echo Chem Presat had the most inaccurate quantification of FS fractions among these six FS methods. Both the ranks of signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs) of the phantom were IDEAL [Formula: see text] FSE T2 FS [Formula: see text] STIR. The FS performance of these six FS methods in clinical use needs further study.