Signal Intensity of Contrast Enhancement according to TE in 3.0T MRI T1 Imaging

Hyun Jeong,Min Kim,Kwon Lee,Ho Kim,Sung Kim

doi:10.3390/app8071138

Abstract

Normal body tissue or lesion characteristics in T1 images have been evaluated; however, how external parameters effect the change in signal intensity by gadolinium-based contrast agent remains unknown. We investigated how contrast enhancement changed according to echo time (TE) in 3.0T magnetic resonance (MR) T1 imaging and determined the optimal settings for TE in contrast-enhanced T1 imaging. Since there are no guidelines regarding parameters for T1 enhancement when using MR-contrast agents, we analyzed results from varying TEs (between 25 and 7 msec) in both a phantom and clinical study. We obtained the following results: contrast percentage of fat to saline increased from 740.0–1003.6%, response start point increased from 30–90 mmol, max peak signal intensity increased from 1771–2425 a.u., max peak point increased from 2–4 mmol, enhancement percentage of the max peak signal intensity (MPSI) to saline increased from 1671.0–2065.2%, the average of SI on each mol as TE increased from 600.8–996.6 a.u., the average of SI as TE on each molar concentration increased from 378–845 a.u., the AEPSS increased from 44.3–140.3%, and the AEPSC increased from 224.3–647.8%. We confirmed that TE can affect contrast enhancement, and the lowest TE has faster and higher effects on contrast enhancement.

Highlights

Magnetic resonance imaging (MRI) is achieved through the paramagnetism of the hydrogen (1 H)protons in the body when placed in a magnetic field
Previous studies have only addressed the characteristics of normal body tissues or lesions in T1 images according to sequences and have shown clinical comparison data according to gadolinium-based contrast agent (GBCA) concentration
There are two methods for T1 effect: spin echo (SE) and turbo spin echo (TSE), the present study examined only the effects of changes in the TE parameter on T1 imaging using conventional SE, which has been usually used for T1 effect in the clinical field [2,7,8]

Summary

Introduction

Magnetic resonance imaging (MRI) is achieved through the paramagnetism of the hydrogen (1 H). Protons in the body when placed in a magnetic field. 1 H protons in various tissues emit different energy signatures depending on the proton relaxation rate in that tissue. MRI displays these energy differences as contrast in a scan image [1,2]. The MRI signal intensity (SI) is determined by the gradient strength (M0 ), flip angle (α), repetition time (TR), echo time (TE), 1/T1 (R1 ), and 1/T2*. (R2 *), as shown in Equation (1) [3,4]; SI = M0 sin(α)· (∗) − e− R1 ·TR ·e R2 TE − R · TR − cos(α)·e (1)

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Discussion

Conclusion