Gradient-echo-based 3D submillisecond echo time pulmonary MR imaging: a preliminary usability study on clinical and preclinical MR scanners

A preliminary investigation of the effects of stimulation of the visual and the motor cortex was made on a conventional 1.5 T MR imaging scanner. Both types of activation gave a detectable change in the signal between rest and stimulation using a gradient echo sequence with an echo time of 60 ms. The observed effects were assumed to be caused by variation in the amount of paramagnetic deoxyhemoglobin between stimulation and rest due to local increase of capillary blood flow in the human brain during stimulation.

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MR Imaging of Articular Cartilage: Comparison of Magnetization Transfer Contrast and Fat - Suppression inMultiplanar and 3D Gradient-Echo, Spin-Echo, Turbo Spin-Echo Techniques

Journal of the Korean Radiological Society ◽

10.3348/jkrs.1999.40.3.577 ◽

1999 ◽

Vol 40 (3) ◽

pp. 577

Author(s):

Young Joon Lee ◽

Eun Young Joo ◽

Choong Ki Eun

Keyword(s):

Articular Cartilage ◽

Mr Imaging ◽

Spin Echo ◽

Magnetization Transfer ◽

Fat Suppression ◽

Turbo Spin Echo ◽

Gradient Echo ◽

Magnetization Transfer Contrast ◽

Turbo Spin

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Faculty Opinions recommendation of Cortical bone water: in vivo quantification with ultrashort echo-time MR imaging.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1149870.606957 ◽

2009 ◽

Author(s):

Maria Cova ◽

Emilio Quaia

Keyword(s):

Mr Imaging ◽

Cortical Bone ◽

Ultrashort Echo Time ◽

Bone Water ◽

Echo Time

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A Useful Combination of Quantitative Ultrashort Echo Time MR Imaging and a Probing Device for Biomechanical Evaluation of Articular Cartilage

Biosensors ◽

10.3390/bios11020052 ◽

2021 ◽

Vol 11 (2) ◽

pp. 52

Author(s):

Takehito Hananouchi ◽

Yanjun Chen ◽

Saeed Jerban ◽

Masaru Teramoto ◽

Yajun Ma ◽

...

Keyword(s):

Mechanical Properties ◽

Mr Imaging ◽

Linear Regression Analysis ◽

Reaction Force ◽

Predictor Variable ◽

Cartilage Tissue ◽

Magnetization Transfer Ratio ◽

Ultrashort Echo Time ◽

Echo Time

In this study, we combined quantitative ultrashort echo time (UTE) magnetic resonance (MR) imaging and an investigation by a probing device with tri-axial force sensor to seek correlations with mechanical properties of human patellar cartilage for in situ evaluation of biomechanical properties. Cartilage blocks (15 × 20 × 5 mm3) were dissected from the patella of six donors; 5 mm square regions of interest from the cartilage blocks were imaged using UTE-MR imaging sequences (T2* and magnetization transfer ratio (MTR)), and mechanical properties were measured using a micro indentation device. Then, the vertical reaction force on the cartilage surface was measured while push-probing forward 3 mm with the probing device at a 30° tilt to the horizontal plane. The results showed a positive correlation between stiffness/elastic modulus and each predictor variable (UTE-T2* (r = 0.240 and 0.255, respectively, UTE-MTR (r = 0.378 and 0.379, respectively), and probing device force (r = 0.426 and 0.423, respectively). Furthermore, multiple linear regression analysis showed the combination of the three predictors had stronger correlation (adjusted r2 = 0.314 (stiffness), 0.323 (elastic), respectively). Our results demonstrate the potential for these non- and less- invasive methods for in situ evaluation of the mechanical properties of cartilage tissue.

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Experimental intracerebral and subarachnoid/intraventricular haemorrhages: MR detectability at 0.5 T and 1.5 T

Acta Radiologica ◽

10.1258/rsmacta.43.5.464 ◽

2002 ◽

Vol 43 (5) ◽

pp. 464-473

Author(s):

M. Alemany Ripoll ◽

R. Raininko

Keyword(s):

Cerebrospinal Fluid ◽

Mr Imaging ◽

Spin Echo ◽

Autologous Blood ◽

Pulse Sequences ◽

Proton Density ◽

Gradient Echo ◽

The Brain ◽

Formalin Fixed

Purpose: To compare the detectability of small experimental intracranial haemorrhages on MR imaging at 0.5 T and 1.5 T, from hyperacute to subacute stages. Material and Methods: 1 ml of autologous blood was injected into the brain of 15 rabbits to create intraparenchymal haematomas. Since the blood partially escaped into the cerebrospinal fluid (CSF) spaces, detectability of subarachnoid and intraventricular blood was also evaluated. MR imaging at 0.5 T and at 1.5 T was repeated up to 14 days, including T1-, proton density- and T2-weighted (w) spin-echo (SE), FLAIR and T2*-w gradient echo (GE) pulse sequences. The last MR investigation was compared to the formalin-fixed brain sections in 7 animals. Results: The intraparenchymal haematomas were best revealed with T2*-w GE sequences, with 100% of sensitivity at 1.5 T and 90–95% at 0.5 T. Blood in the CSF spaces was significantly ( p < 0.05) better detected at 1.5 T with T2*-w GE sequences and detected best during the first 2 days. The next most sensitive sequence for intracranial blood was FLAIR. SE sequences were rather insensitive. Conclusion: 1.5 T equipment is superior to 0.5 T in the detection of intracranial haemorrhages from acute to subacute stages. T2*-w GE sequences account for this result but other sequences are also needed for a complete examination.

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