Examination of Measurement and Its Method of Compensation of the Sensitivity Distribution Using Phased Array Coil for Body Scan

Kimura, Tetsuya; Tahara, Daise; Iiduka, Akihisa; Taniguchi, Y.; Ishikuro, Akihiro; Hongo, Takaharu; Inoue, Hiroshi; Ogura, Akio

doi:10.6009/jjrt.kj00000922229

Cited by 6 publications

(6 citation statements)

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“…Although a built-in BC that has a uniform SI distribution is an ideal coil to quantitatively measure contrasts, Gd-EOB-DTPA-enhanced MRI is generally performed with PACs to acquire images of high sensitivity and resolution ( 20 ). PACs have a concave distribution of SI ( 21 ). Therefore, it is necessary to smooth this distribution by an image-based correction technique (e.g., SCIC or homogeneity correction), which adjusts the SIs by predetermined coefficients, or a calibration-based correction technique (e.g., PURE or CLEAR), which uses the reference images of the built-in BC ( 20 , 21 ).…”

Section: Discussionmentioning

confidence: 99%

“…PACs have a concave distribution of SI ( 21 ). Therefore, it is necessary to smooth this distribution by an image-based correction technique (e.g., SCIC or homogeneity correction), which adjusts the SIs by predetermined coefficients, or a calibration-based correction technique (e.g., PURE or CLEAR), which uses the reference images of the built-in BC ( 20 , 21 ). However, it had been pointed out that the images rendered by these correction methods cannot be used for quantitative evaluation using contrasts, because these techniques lower the LSC and cannot recover the contrast among organs ( 20 ).…”

Section: Discussionmentioning

confidence: 99%

“…The measurement values were represented by the ratio to the center (0 cm). In addition, the influence of the interval between confronting PACs on contrasts (21) was examined with the aim of grasping the influence of body thickness on contrasts. The phantoms of CuSO 4 aqueous solution were set on the center between the anterior and posterior T-PACs, and the PC was measured at intervals of 14, 17, 20, 24, and 27 cm (Figure 2B).…”

Section: Verification Of the Setting Methods Of Two Roismentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

“…On PAC, the SI was the concave distribution in the anterior–posterior direction, which was perpendicular to the anterior and posterior PACs, because the PAC was made by linking the small plural radiofrequency coils on a plane ( Figure 1A ) ( 21 ). Furthermore, even if the SCIC was applied, the SI drop remained in the central portion of the images ( Figure 1B ) ( 21 ). Therefore, in measuring the contrasts using T-PAC, two ROIs of the liver and spleen were placed at the same distance from the PACs in order to keep the same condition of the SI drop between these two ROIs ( Figure 2C,2D ).…”

Section: Methodsmentioning

confidence: 99%

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Liver-spleen contrast standardization of gadolinium-ethoxybenzyl-diethylenetriamine penta-acetic acid-enhanced magnetic resonance imaging based on cross-calibration

Mori¹,

Akimoto²

2022

Quant Imaging Med Surg

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Background: Liver-spleen contrast in the hepatobiliary phase highly depends on the devices used for liver function tests. This study aimed to develop and validate a method to convert liver-spleen contrast data acquired with another device to reference liver-spleen contrast data, using the regression line of phantom contrasts (i.e., cross-calibration).Methods: As cohort studies, two-dimensional gradient echo images of T1-weighted fat-suppression in the hepatobiliary phase were retrospectively obtained and analyzed for a total of 126 patients who underwent gadolinium-ethoxybenzyl-diethylenetriamine penta-acetic acid-enhanced magnetic resonance imaging using four different magnetic resonance imaging scanner-coil combinations. The liver-spleen contrast measured from these images was converted into reference liver-spleen contrast using cross-calibration with purified water and gadolinium-ethoxybenzyl-diethylenetriamine penta-acetic acid phantoms of 0.06, 0.14, 0.27, 0.63, 1.37, and 2.82 mM/L. At this point, the error of the regression lines with phantom contrasts was assessed and corrected. Lastly, the liver-spleen and converted liver-spleen contrasts, which are the values before and after cross-calibration respectively, were compared with reference liver-spleen contrast in three cases using different coils and magnetic resonance imaging scanners from a reference device.Results: Regarding the regression lines with phantom contrasts, the coefficient of determination was 0.99.Although regression lines with phantom contrasts tended to be 0.0105 lower in logarithmic contrasts than those with liver-spleen contrast, no significant difference was observed between the two lines (P=0.0612) by analysis of covariance. In the case of different coils, there was a significant difference between liver-spleen and reference liver-spleen contrasts (P<0.00001), but there was no significant difference between converted liver-spleen and reference liver-spleen contrasts (P=0.492). Moreover, the regression equation between converted liver-spleen and reference liver-spleen contrasts corresponded with an identity line. Likewise, in the two cases of different magnetic resonance imaging scanners, there was a significant difference between liver-spleen and reference liver-spleen contrast (both P<0.00001), but there was no significant difference between converted liver-spleen and reference liver-spleen contrast (P=0.923 and P=0.541).Conclusions: Cross-calibration using the precision and valid regression lines with phantom contrasts had high accuracy and utility.^ ORCDI: 0000-0003-1378-5970.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Verification Of the Setting Methods Of Two Roismentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 3 more Smart Citations

Liver-spleen contrast standardization of gadolinium-ethoxybenzyl-diethylenetriamine penta-acetic acid-enhanced magnetic resonance imaging based on cross-calibration

Mori¹,

Akimoto²

2022

Quant Imaging Med Surg

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Examination of Sensitivity Distribution Characteristics Depending on the Position of the Array Coil

Takatsu¹,

Kimura²,

Ishikuro³

et al. 2012

Nippon Hoshasen Gijutsu Gakkai Zasshi

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SummaryThe opposite-type array coil is useful because it is easy to attach in magnetic resonance imaging (MRI) examinations away from the center area. It is not well understood that sensitivity characteristics change when coil elements shift. We studied the effect when both coil elements (17×14 cm) shifted to the opposite side; we examined a hand including the wrist. The signal-to-noise ratio (SNR) of the axial image by the subtraction map declined 2.6%/cm. The profile of the sagittal and coronal view by the SNR map shows that the greater the distance between the center of the upper and lower coil elements, the lower the SNR is on the center of the examination area and the higher the SNR is on the edge of the examination area. In removing 10 cm from each of the coil elements, the profile became wide and linear. In the case of removing more than 7.5 cm, the wide area of uniformity was shown in the center of the images of sensitivity distribution. Uniformity by the segment method increased more than 10 cm. Use of the opposite-type array coil when shifting both coil elements to the opposite side may extend the examination area.

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The Position Dependent Influence That Sensitivity Correction Processing Gives the Signal-to-noise Ratio Measurement in Parallel Imaging

Murakami¹,

Yoshida²,

Yanagimoto³

2012

Nippon Hoshasen Gijutsu Gakkai Zasshi

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We studied the position dependent influence that sensitivity correction processing gave the signal-to-noise ratio (SNR) measurement of parallel imaging (PI). Sensitivity correction processing that referred to the sensitivity distribution of the body coil improved regional uniformity more than the sensitivity uniformity correction filter with a fixed correction factor. In addition, the position dependent influence to give the SNR measurement in PI was different from the sensitivity correction processing. Therefore, if we divide SNR of the sensitivity correction processing image by SNR of the original image in each pixel and calculate SNR ratio, we can show the position dependent influence that sensitivity correction processing gives the SNR measurement in PI. It is with an index of the sensitivity correction processing precision.

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Examination of Measurement and Its Method of Compensation of the Sensitivity Distribution Using Phased Array Coil for Body Scan

Cited by 6 publications

References 1 publication

Liver-spleen contrast standardization of gadolinium-ethoxybenzyl-diethylenetriamine penta-acetic acid-enhanced magnetic resonance imaging based on cross-calibration

Liver-spleen contrast standardization of gadolinium-ethoxybenzyl-diethylenetriamine penta-acetic acid-enhanced magnetic resonance imaging based on cross-calibration

Examination of Sensitivity Distribution Characteristics Depending on the Position of the Array Coil

The Position Dependent Influence That Sensitivity Correction Processing Gives the Signal-to-noise Ratio Measurement in Parallel Imaging

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