Characteristic signal intensity changes on postmortem magnetic resonance imaging of the brain

Kobayashi, Tomoya; Shiotani, Seiji; Kaga, Kazunori; Saito, Hajime; Saotome, Kousaku; Miyamoto, Katsumi; Kohno, Mototsugu; Kikuchi, Kazunori; Hayakawa, Hideyuki; Homma, Kazuhiro

doi:10.1007/s11604-009-0373-9

Cited by 56 publications

(35 citation statements)

References 31 publications

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“…[25][26][27][28] However, when postmortem examination employs the TI routinely used for living bodies, lesion detection by FLAIR imaging is diminished by unclear image contrast 18,19 caused by insufficient signal suppression of the CSF. Thus, parameters for FLAIR of PMMR imaging should be optimized for deceased subjects.…”

Section: Discussionmentioning

confidence: 99%

“…However, consensus regarding what constitutes a normal appearance on PMMR images is difficult because T 1 and T 2 values change according to body temperature. 12,[18][19][20] Therefore, acquisition of appropriate image contrast for deceased bodies at low temperatures re-*Corresponding author, Phone: +81-92-554-1255, Fax: +81-92-552-2707, E-mail: abe.k@junshin-u.ac.jp quires optimization of the parameters for PMMR imaging. Short-tau inversion recovery (STIR) and fluidattenuated inversion recovery (FLAIR) are typical sequences employed to suppress tissue signal.…”

Section: Introductionmentioning

confidence: 99%

“…21 Application of the inversion time (TI) for living bodies for PMMR imaging does not adequately suppress fat signals in STIR and CSF signals in FLAIR. [18][19][20] Suppression of the signal intensity (SI) of fat has been reported with STIR in PMMR imaging when using an optimized TI based on the measured rectal temperature (RT). 22 Therefore, we surmised that the SI of CSF can also be suppressed on postmortem FLAIR images by adjusting the TI according to the T 1 temperature dependence of water.…”

Section: Introductionmentioning

confidence: 99%

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Optimization of Inversion Time for Postmortem Fluid-attenuated Inversion Recovery (FLAIR) MR Imaging at 1.5T: Temperature-based Suppression of Cerebrospinal Fluid

et al. 2015

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Purpose: Signal intensity (SI) and image contrast on postmortem magnetic resonance (MR) imaging are different from those of imaging of living bodies. We sought to suppress the SI of cerebrospinal fluid (CSF) sufficiently for fluid-attenuated inversion recovery (FLAIR) sequence in postmortem MR (PMMR) imaging by optimizing inversion time (TI).Materials and Methods: We subject 28 deceased patients to PMMR imaging 3 to 113 hours after confirmation of death (mean, 27.4 hrs.). PMMR imaging was performed at 1.5 tesla, and T 1 values of CSF were measured with maps of relaxation time. Rectal temperatures (RT) measured immediately after PMMR imaging ranged from 6 to 32°C (mean, 15.4°C). We analyzed the relationship between T 1 and RT statistically using Pearson's correlation coefficient. We obtained FLAIR images from one cadaver using both a TI routinely used for living bodies and an optimized TI calculated from the RT.Results: T 1 values of CSF ranged from 2159 to 4063 ms (mean 2962.4), and there was a significantly positive correlation between T 1 and RT (r = 0.96, P < 0.0001). The regression expression for the relationship was T 1 = 74.4 * RT + 1813 for a magnetic field strength of 1.5T. The SI of CSF was effectively suppressed with the optimized TI (0.693 * T 1 ), namely, TI = 0.693 * (77.4 * RT + 1813).Conclusion: Use of the TI calculated from the linear regression of the T 1 and RT optimizes the FLAIR sequence of PMMR imaging.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Optimization of Inversion Time for Postmortem Fluid-attenuated Inversion Recovery (FLAIR) MR Imaging at 1.5T: Temperature-based Suppression of Cerebrospinal Fluid

et al. 2015

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“…Therefore, PMMR imaging shows changes in SI in response to lowering body temperature after death. [12][13][14] It is difficult to achieve a consensus on the normal appearance of PMMR because these changes depend on temperature. Therefore, PMMR parameter optimization is needed to obtain appropriate image contrast for bodies at low temperatures.…”

Section: Introductionmentioning

confidence: 99%

“…15 However, routine parameters for MR imaging of the living body do not suppress the SI of cerebrospinal fluid (CSF) of cadavers. 12,13,16 Tofts and associates reported that T 1 values of the CSF can be derived by measuring the diffusion coefficient of the CSF at low temperatures. CSF signals of the cadaveric brain can then be suppressed effectively by using an optimized inversion time (TI).…”

Section: Introductionmentioning

confidence: 99%

Optimization of Inversion Time for Postmortem Short-tau Inversion Recovery (STIR) MR Imaging

et al. 2014

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Purpose: Signal intensity and image contrast differ between postmortem magnetic resonance (PMMR) images and images acquired from the living body. We sought to achieve sufficient fat suppression with short-tau inversion recovery (STIR) PMMR imaging by optimizing inversion time (TI).Material and Methods: We subjected 37 deceased adult patients to PMMR imaging at 1.5 tesla 8 to 60 hours after confirmation of death and measured T 1 values of areas of subcutaneous fat with relaxation time maps. Rectal temperature (RT) measured immediately after PMMR ranged from 6 to 31°C. We used Pearson's correlation coefficient to analyze the relationship between T 1 and relaxation time (RT). We compared STIR images from 4 cadavers acquired with a TI commonly used in the living body and another TI calculated from the linear regression of T 1 and RT.Results: T 1 values of subcutaneous fat ranged from 89.4 to 182.2 ms. There was a strong, positive, and significant correlation between T 1 and RT (r = 0.91, P < 0.0001). The regression expression for the relationship was T 1 = 2.6*RT + 90 at a field strength of 1.5T. The subcutaneous fat signal was suppressed more effectively with the optimized TI.Conclusion: The T 1 value of subcutaneous fat in PMMR correlates linearly with body temperature. Using this correlation to determine TI, fat suppression with PMMR STIR imaging can be easily improved.

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Cerebrospinal fluid T1 value phantom reproduction at scan room temperature

Yamashiro

Kobayashi

Saito

2019

J Applied Clin Med Phys

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The T1 value of pure water, which is often used as a phantom to simulate cerebrospinal fluid, is significantly different from that of in‐vivo cerebrospinal fluid. The purpose of this study was to develop a phantom with a T1 value equivalent to that of in‐vivo cerebrospinal fluid under examination room temperature (23°C–25°C). In this study, 1.5 and 3.0 T magnetic resonance imaging scanners were used. We examined the signal intensity change in relation to pure water temperature, the T1 values of acetone‐diluted solutions (0–100 v/v%, in 10 steps), and the correlation coefficients obtained from volunteers and the prepared phantoms. The T1 value was close to the value reported in the literature for cerebrospinal fluid when the acetone‐diluted solution was 70 v/v% or higher at scan room temperature. The value at that time was 3532.81–4704.57 ms at 1.5 T and it ranged from 4052.41 to 5701.61 ms at 3.0 T. The highest correlation with the values obtained from the volunteers was r = 0.993 with pure acetone at 1.5 T and r = 0.991 with acetone 90 v/v% at 3.0 T. The relative error of the best phantom‐volunteer match was 32.61 (%) ± 6.71 at 1.5 T and 46.67 (%) ± 4.31 at 3.0 T. The T1 value measured by the null point method did not detect a significant difference between in vivo CSF and acetone 100 v/v% at 1.5 T and acetone 90 v/v% at 3.0 T. The T1 value of cerebrospinal fluid in the living body at scan room temperature was reproduced with acetone. The optimum concentration of acetone for cerebrospinal‐fluid reproduction was pure acetone at 1.5 T and 90 v/v% at 3.0 T.

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Characteristic signal intensity changes on postmortem magnetic resonance imaging of the brain

Abstract: Postmortem MRI of the brain in all cases showed characteristic common SI changes. Global cerebral ischemia without following reperfusion and low body temperature explain these changes.

Cited by 56 publications

References 31 publications

Optimization of Inversion Time for Postmortem Fluid-attenuated Inversion Recovery (FLAIR) MR Imaging at 1.5T: Temperature-based Suppression of Cerebrospinal Fluid

Optimization of Inversion Time for Postmortem Fluid-attenuated Inversion Recovery (FLAIR) MR Imaging at 1.5T: Temperature-based Suppression of Cerebrospinal Fluid

Optimization of Inversion Time for Postmortem Short-tau Inversion Recovery (STIR) MR Imaging

Cerebrospinal fluid T1 value phantom reproduction at scan room temperature

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