Clinical Application of MPRAGE Wave Controlled Aliasing in Parallel Imaging (Wave-CAIPI): A Comparative Study with MPRAGE GRAPPA

PURPOSE: To compare reliability and elucidate clinical application of magnetization-prepared rapid gradient-echo (MPRAGE) with 9-fold acceleration by using wave-controlled aliasing in parallel imaging (Wave-CAIPI 3 × 3) in comparison to conventional MPRAGE accelerated by using generalized autocalibrating partially parallel acquisition (GRAPPA) 2 × 1. METHODS: A total of 26 healthy volunteers and 33 patients were included in this study. Subjects were scanned with two MPRAGEs, GRAPPA 2 × 1 and Wave-CAIPI 3 × 3 acquired in 5 min 21 s and 1 min 42 s, respectively, on a 3T MR scanner. Healthy volunteers underwent additional two MPRAGEs (CAIPI 3 × 3 and GRAPPA 3 × 3). The image quality of the four MPRAGEs was visually evaluated with a 5-point scale in healthy volunteers, and the SNR of four MPRAGEs was also calculated by measuring the phantom 10 times with each MPRAGE. Based on the results of the visual evaluation, voxel-based morphometry (VBM) analyses, including subfield analysis, were performed only for GRAPPA 2 × 1 and Wave-CAIPI 3 × 3. Correlation of segmentation results between GRAPPA 2 × 1 and Wave-CAIPI 3 × 3 was assessed. RESULTS: In visual evaluations, scores for MPRAGE GRAPPA 2 × 1 (mean rank: 4.00) were significantly better than those for Wave-CAIPI 3 × 3 (mean rank: 3.00), CAIPI 3 × 3 (mean rank: 1.83), and GRAPPA 3 × 3 (mean rank: 1.17), and scores for Wave-CAIPI 3×3 were significantly better than those for CAIPI 3 × 3 and GRAPPA 3 × 3. Image noise was evident at the center for additional MPRAGE CAIPI 3 × 3 and GRAPPA 3 × 3. The correlation of segmentation results between GRAPPA 2 × 1 and Wave-CAIPI 3 × 3 was higher than 0.85 in all VOIs except globus pallidus. Subfield analysis of hippocampus also showed a high correlation between GRAPPA 2 × 1 and Wave-CAIPI 3 × 3. CONCLUSION: MPRAGE Wave-CAIPI 3 × 3 shows relatively better contrast, despite of its short scan time of 1 min 42 s. The volumes derived from automated segmentation of MPRAGE Wave-CAIPI are considered to be reliable measures

Signal Intensity and Volume of Pituitary and Thyroid Glands in Preterm and Term Infants

[Background]: Hypothalamic–pituitary–thyroid (HPT) maturation has not been extensively evaluated using neonatal MRI, even though both structures are visualized on MRI. [Hypothesis]: That signal intensity and volume of pituitary and thyroid (T) glands on MRI in neonates may be interrelated. [Study Type]: Retrospective. [Subjects]: In all, 102 participants. [Field Strength/Sequence]: 3.0T, T₁‐weighted pointwise encoding time reduction with radial acquisition (PETRA).[ Assessment]: The volume of interest of the anterior pituitary (AP), posterior pituitary (PP), and T on MRI were defined on T₁‐PETRA by two radiologists, and volumes of AP (AP_vol) and thyroid (T_vol) were calculated. Gestational age (GA), chronological age (CA), GA+CA, birth weight (BW), and thyroid function were recorded. Mean and maximum signal intensities of AP, PP, and T were normalized using signals from the pons and spinal cord as follows: signal ratio of anterior pituitary/pons (AP/pons), signal ratio of posterior pituitary/pons (PP/pons), and signal ratio of thyroid/cord (T/cord) T/cord, respectively. [Statistical Tests]: Correlations between signal intensity and volume measures and GA, CA, GA+CA, and BW were assessed using Pearson's correlation coefficient or Spearman's rank correlation coefficient. Thyroid function analysis and Tmean/cord, Tmax/cord, and T_vol were evaluated using the Steel–Dwass test. Results: APmean/pons correlated positively with GA (ρ = 0.62, P < 0.001) and BW (ρ = 0.74, P < 0.001), and negatively with CA (ρ = −0.86, P < 0.001) and GA+CA (ρ = −0.46, P < 0.001). PPmean/pons correlated positively with GA (ρ = 0.49, P < 0.001) and BW (ρ = 0.63, P < 0.001), and negatively with CA (ρ = −0.70, P < 0.001) and GA+CA (r = −0.38, P < 0.001). Tmean/cord correlated positively with GA (ρ = 0.48, P < 0.001) and BW (ρ = 0.55, P < 0.001), and negatively with CA (ρ = −0.59, P < 0.001) and GA+CA (ρ = −0.22, P = 0.03). AP_vol correlated positively with GA (ρ = 0.68, P < 0.001) and BW (ρ = 0.73, P < 0.001), and negatively with CA (ρ = −0.72, P < 0.001). T_vol correlated positively with GA (ρ = 0.50, P < 0.001) and BW (ρ = 0.61, P < 0.001), and negatively with CA (ρ = −0.54, P < 0.001). APmean/pons correlated positively with Tmean/cord (ρ = 0.61, P < 0.001). [Data Conclusion]: Signal and volume of pituitary and thyroid glands correlated positively with GA and BW, and negatively with CA in neonates. [Level of Evidence]: 4 [Technical Efficacy Stage]:

Isolation and Characterization of Microsatellite Loci in the Invasive Herb <i>Solidago altissima</i> (Asteraceae)

Premise of the study: Microsatellite markers were developed in the perennial herb Solidago altissima from populations within its introduced range in Japan to assess its population structure and to facilitate tracking of invasion expansion. Methods and Results: Using 454 pyrosequencing, 16 microsatellite primer sets were developed for S. altissima. The primer sets were tested on 70 individuals sampled from three populations in Japan. The primers amplified di- and trinucleotide repeats with five to 25 alleles per locus, and the expected heterozygosity ranged from 0.46 to 0.92. Conclusions: These results indicate the utility of primers in S. altissima for future research on a wide range of applications, including tracking of invasion dynamics and investigating population genetics of the species

Regulation of pyrophosphate levels by H+-PPase is central for proper resumption of early plant development

The synthesis of DNA, RNA, and de novo proteins is fundamental for early development of the seedling after germination, but such processes release pyrophosphate (PPi) as a byproduct of ATP hydrolysis. The over-accumulation of the inhibitory metabolite PPi in the cytosol hinders these biosynthetic reactions. All living organisms possess ubiquitous enzymes collectively called inorganic pyrophosphatases (PPases), which catalyze the hydrolysis of PPi into two orthophosphate (Pi) molecules. Defects in PPase activity cause severe developmental defects and/or growth arrest in several organisms. In higher plants, a proton-translocating vacuolar PPase (H+­PPase) uses the energy of PPi hydrolysis to acidify the vacuole. However, the biological implications of PPi hydrolysis are vague due to the widespread belief that the major role of H+­PPase in plants is vacuolar acidification. We have shown that the Arabidopsis fugu5 mutant phenotype, caused by a defect in H+­PPase activity, is rescued by complementation with the yeast cytosolic PPase IPP1. In addition, our analyses have revealed that increased cytosolic PPi levels impair postgerminative development in fugu5 by inhibiting gluconeogenesis. This led us to the conclusion that the role of H+­PPase as a proton-pump is negligible. Here, we present further evidence of the growth-boosting effects of removing PPi in later stages of plant vegetative development, and briefly discuss the biological role of PPases and their potential applications in different disciplines and in various organisms

Measurement of the Bicycle Driving Time Using a Triaxial Accelerometer System

〔目的 〕3軸加速度計システムを用いて自転車駆動を判別し，その駆動時聞を測定することを目的とした. 〔対象〕実験1では健常学生11名，実験2では健常学生9名を対象とした. 〔方法〕実験1では，対象者に2つの3軸加速度計を装着させ，自転車を含む日常生活動作を行わせた. 3紬加速度計が記録した加速度から変動値を算出し，総時聞における判別された時聞の割合から判別闘値を検討した.実験2では，対象者に3軸加速度計を装着させ実験1と同様の活動を行わせ，その様子をビデオカメラで撮影した.次に，加速度計とピデオカメラから各動作の総時聞を求めBland-Altman解析を用い比較した. 〔結果〕実験1の結果，判別された時聞の割合が90%以上である闘値を自転車の判別闘値と決定した.実験2の結果， 3紬加速度計とビデオカメラから求めた測定時聞は全ての活動において強い相闘がみられた.また，加算誤差，比例誤差は認められなかった. 〔結語〕これらの実験結果から， 3軸加速度計システムを用いた自転車駆動の判定と駆動時間測定方法の信頼性が示唆された.[Purpose] The purpose of this study was to . discriminate the movement of bicycle drive and measure the time spent operating a bicycle using a new triaxial accelerometer system. [Suhjects] Eleven healthy students participated in the first experiment and nine healthy students participated in the second experiment. [Methods] Subjects wearing two accelerometers carried out the activities of daily living, including a bicycle drive, in the first experiment. We evaluated the variation values from the data obtained from the acceleration accelerometer system and determined the discriminating threshold from the percentages of times analyzed to be during the bicycle drive in the total times. Subjects wearing two accelerometers carried out the activities of daily living, including a bicycle drive, and were videotaped in the second experiment. The times obtained by these two methods were compared using the Bland-Altman method. [Results] The discriminating threshold was capable of distinguishing the bicycle operating time at a ratio of 90% or more in the first experiment. There was a strong and significant correlation among all the activity times measured by the video camera and the accelerometer, and no flxed or proportional errors were observed in the second experiment. [Conclusion] These data suggest the reliability of using the new triaxial accelerometer system to measure the time spent operating a bicycle