Spin-lock imaging in contrast enhanced magnetic resonance imaging of human gliomas

Aronen, Hannu J.; Peltonen, T; Tanttu, Jukka I.; Sipilä, Leena M.; Ruhala, Marko; Jääskeläinen, Juha E.; Sepponen, Raimo

doi:10.1016/s1076-6332(96)80524-1

Cited by 3 publications

(5 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The complication of reducing TR is the reduced recovery of the longitudinal magnetization. At steady state, this introduces T 1 contamination, as described by Aronen et al The ability to accurately report and compare T 1ρ values across different pulse sequences and field strengths is important. To accurately account for T 1 contamination, T 2 * and T 1 values of the tissue are required, resulting in increased scan time.…”

Section: Discussionmentioning

confidence: 99%

“…However, this approach may result in significant T 1 contamination because of incomplete recovery of the longitudinal magnetization. 21 T 1 compensation is necessary for accurate measurement of T 1ρ based on the following equation:

S ((),, TSL) \propto \frac{e^{- italicTSL true/ T 1 normalρ} \times (1 - e^{- ((),, italicTR - italicTSL) true/ T 1}}{1 - e^{- italicTSL true/ T 1 normalρ} \times e^{- ((),, italicTR - italicTSL) true/ T 1} \times italiccosα} \times italicsinα + C

where TR is the time between RF excitation pulses with a flip angle α , T 1ρ is the spin–lattice relaxation time of the tissue of interest and T 1 is the longitudinal relaxation time of the tissue of interest. A constant term C is introduced to account for background noise and artifacts associated with 3D UTE‐Cones‐ T 1ρ data acquisition and image reconstruction.…”

Section: Methodsmentioning

confidence: 99%

Section: Pulse Sequencementioning

confidence: 99%

“…FS, fat saturation FIGURE 4 Selected three-dimensional ultrashort echo time cones T 1ρ (3D UTE-cones-T 1ρ ) images of a cadaveric human Achilles tendon sample with a TE of 32 μs and different spin-locking times (TSLs) of 0.02 ms (a), 1 ms (B), 5 ms (C) and 10 ms (D), as well as spiral-T 1ρ imaging of the same sample with a TE of 5.6 ms and different TSLs of 0.02 ms (E), 1 ms (F), 5 ms (G) and 10 ms (H). T 1ρ of the Achilles tendon sample can only be quantified with the 3D UTE-cones-T 1ρ sequence, which showed a T 1ρ value of 4.0 ± 0.9 ms (I) described by Aronen et al 21 The ability to accurately report and compare T 1ρ values across different pulse sequences and field strengths is important. To accurately account for T 1 contamination, T 2 * and T 1 values of the tissue are required, 29 resulting in increased scan time.…”

Section: Phantom Ex Vivo and In Vivo Studiesmentioning

confidence: 99%

See 3 more Smart Citations

Three‐dimensional ultrashort echo time cones T_1ρ (3D UTE‐cones‐T_1ρ) imaging

Carl²,

Shao

et al. 2017

NMR in Biomedicine

View full text Add to dashboard Cite

We report a novel three-dimensional (3D) ultrashort echo time (UTE) sequence employing Cones trajectory and T1ρ preparation (UTE-Cones-T1ρ) for quantitative T1ρ assessment of short T2 tissues in the musculoskeletal system. A basic 3D UTE-Cones sequence was combined with a spin-locking preparation pulse for T1ρ contrast. A relatively short TR was used to decrease scan time, which required T1 measurement and compensation using 3D UTE-Cones data acquisitions with variable TRs. Another strategy to reduce the total scan time was to acquire multiple Cones spokes (Nsp) after each T1ρ preparation and fat saturation. A total of four spin-locking times (TSLs = 0 – 20 ms) were acquired under 12 minutes plus another 7 minutes for T1 measurement. The 3D UTE-Cones-T1ρ sequence was compared with a 2D spiral-T1ρ sequence for imaging of a spherical CuSO4 phantom and ex vivo meniscus and tendon specimens, as well as the knee and ankle joints of healthy volunteers using a clinical 3T scanner. The CuSO4 phantom showed a T1ρ value of 76.5 ± 1.6 ms with the 2D spiral-T1ρ sequence, as well as 85.7 ± 3.6 ms and 89.2 ± 1.4 ms for the 3D UTE-Cones-T1ρ sequences with Nsp of 1 and 5, respectively. The 3D UTE-Cones-T1ρ sequence provided shorter T1ρ values for the bovine meniscus sample compared to the 2D spiral-T1ρ sequence (10 – 12 ms vs 16 ms, respectively). The cadaveric human Achilles tendon sample could only be imaged with the 3D UTE-Cones-T1ρ sequence (T1ρ = 4.0 ± 0.9 ms), with the 2D spiral-T1ρ sequence demonstrating near zero signal intensity. Human studies yielded T1ρ values of 36.1 ± 2.9 ms, 18.3 ± 3.9 ms and 3.1 ± 0.4 ms for articular cartilage, meniscus and the Achilles tendon, respectively. The 3D UTE-Cones-T1ρ sequence allows volumetric T1ρ measurement of short T2 tissues in vivo.

show abstract

Section: Discussionmentioning

confidence: 99%

S ((),, TSL) \propto \frac{e^{- italicTSL true/ T 1 normalρ} \times (1 - e^{- ((),, italicTR - italicTSL) true/ T 1}}{1 - e^{- italicTSL true/ T 1 normalρ} \times e^{- ((),, italicTR - italicTSL) true/ T 1} \times italiccosα} \times italicsinα + C

Section: Methodsmentioning

confidence: 99%

Section: Pulse Sequencementioning

confidence: 99%

Section: Phantom Ex Vivo and In Vivo Studiesmentioning

confidence: 99%

See 2 more Smart Citations

Three‐dimensional ultrashort echo time cones T_1ρ (3D UTE‐cones‐T_1ρ) imaging

Carl²,

Shao

et al. 2017

NMR in Biomedicine

View full text Add to dashboard Cite

show abstract

“…81 At the time of writing very few reports pertaining to this hypothesis exist. [82][83][84][85] With the exception of one publication investigating spin locking with Ablavar, 82 the focus has solely been on Magnevist and the study of imaging metrics such as contrast and contrast to noise ratio (CNR) [83][84][85] rather than the specific effect on relaxivity, a key indicator of CA effectiveness and determinant of agent detectability.…”

Section: Establishing the Potential Benefits Of Spin Locking On Relaxmentioning

confidence: 99%

Investigation in to the Effect of Spin Locking on Contrast Agent Relaxivity

Haigh¹

2000

View full text Add to dashboard Cite

The current trend in magnetic resonance imaging (MRI) is towards higher external magnetic field strengths (B0) to take advantage of increased sensitivity and signal to noise ratio (SNR). Unfortunately, as B0 increases the effectiveness (relaxivity) of clinical gadolinium (Gd 3+)-based contrast agents (CAs) administered to enhance image contrast is significantly reduced. Excellent soft tissue contrast can be generated with current agents despite their non-optimum relaxivities but necessitates large doses. The limits of detection of a CA at high B0 fields can be lowered by recovering the lost relaxivity and is a prerequisite to the goal of molecular imaging in which CAs are bound to biomarkers of pathology that exist at very low concentrations. Traditional methods for increasing the detectability of CAs have focused on optimizing critical parameters identified from the Solomon-Bloembergen-Morgan (SBM) theory that affect relaxivity. Gains in relaxivity with these methods to date have been modest and are far from the theoretical maximum possible. Although researchers continue to investigate novel complexes that provide improved relaxivities, any such complex would require a lengthy and costly approval process with the U.S. Food and Drug Administration (FDA). Therefore, a method that affords improved relaxivities of current clinically approved CAs, particularly at high B0 fields, that could be adopted into clinical practice rapidly, is of great interest. Spin locking is a nuclear magnetic resonance (NMR) technique that was introduced for imaging in 1985, but has received very little attention in combination with Gd 3+-based CAs. The technique employs a low power long duration radiofrequency (RF) pulse (B1) I would like to take this opportunity to thank the following: Prof. Mark Woods for all his support, encouragement and assistance throughout the course of this research.

show abstract