T1ρ mapping improvement using stretched-type adiabatic locking pulses for assessment of human liver function at 3T

13301甲第4616号博士（保健学）金沢大学博士論文要旨Abstract 以下に掲載：Magnetic Resonance Imaging 40 pp.17-23 2017. Elsevier. 共著者：Tomoyuki Okuaki, Yukihisa Takayama, Akihiro Nishie, Tetsuo Ogino, Makoto Obara, Hiroshi Honda, Tosiaki Miyati, Marc Van Cautere

Highly Accurate Analysis of the Cervical Neural Tract of the Elderly Using ZOOM DTI

Background/Aims To investigate the fractional anisotropy (FA) values of the cervical spinal cord in elderly individuals using zonally magnified oblique multislice (ZOOM) diffusion tensor imaging (DTI). Methods Fourteen healthy elderly volunteers (group E) and 10 young volunteers (group Y) were enrolled. We assessed the FA, apparent diffusion coefficient (ADC), and λ1–λ3 values using 3-T magnetic resonance imaging. The region of interest was contoured entirely inside the spinal cord, with no gray/white matter distinction, in order to avoid including the cerebrospinal fluid. Results As lower cervical levels were approached, the FA values gradually decreased, while the ADC values increased. The mean FA values at each cervical level were as follows in groups E and Y: 0.71 and 0.70 at the C2/3 level, 0.66 and 0.66 at the C3/4 level, 0.63 and 0.62 at the C4/5 level, 0.57 and 0.57 at the C5/6 level, and 0.58 and 0.57 at the C6/7 level, respectively. The mean ADC values in groups E and Y were 1.06 and 0.99 at the C2/3 level, 1.05 and 1.06 at the C3/4 level, 1.14 and 1.06 at the C4/5 level, 1.18 and 1.21 at the C5/6 level, and 1.39 and 1.46 at the C6/7 level, respectively. There were no significant differences between the elderly and young participants. Conclusion In both asymptomatic elderly and young individuals, the FA values gradually decreased and the ADC values increased moving towards lower cervical levels. Age did not affect the FA values, even though mild cord compression was evident due to spondylotic changes. ZOOM DTI has the potential to provide more information than conventional DTI

Application of non-Gaussian water diffusional kurtosis imaging in the assessment of uterine tumors: A preliminary study.

To evaluate the interobserver reliability and value of diffusional kurtosis imaging (DKI) in the assessment of uterine tumors compared with those of conventional diffusion-weighted imaging (DWI).This retrospective study was approved by our institutional review board, which waived the requirement for informed consent. Fifty-eight women (mean age: 55.0 ± 13.6 years; range: 30-89 years) with suspected malignant uterine tumors underwent 3-T magnetic resonance imaging using DKI and DWI. Twelve had coexisting leiomyoma. Two observers analyzed region-of-interest measurements of diffusivity (D), kurtosis (K), and the apparent diffusion coefficient (ADC) of uterine lesions and healthy adjacent tissues. Interobserver agreement was evaluated using the intra-class correlation coefficient (ICC). The mean values were compared using one-way analysis of variance with a post-hoc Tukey's honestly significant difference test. The diagnostic accuracy of D and ADC in differentiating malignant tumors from benign leiomyomas was analyzed using receiver operating characteristic (ROC) analysis.The ICCs between the two observers in evaluating D, K, and the ADC of the malignant tumors were higher than 0.84, suggesting excellent interobserver agreements. The mean D (×10-3 mm2/s) of uterine cancers (1.05 ± 0.41 and 1.09 ± 0.40 for observers 1 and 2, respectively) were significantly lower than those of leiomyoma (1.40 ± 0.37 and 1.56 ± 0.33, respectively; P 0.1).Interobserver agreements in evaluating D, K, and ADC were moderate to excellent. D performed equally to conventional DWI in differentiating between benign and malignant uterine lesions. The mean K of malignant uterine lesions was significantly higher than that of non-tumorous myometrium or endometrium

Identification and further differentiation of subendocardial and transmural myocardial infarction by fast strain-encoded (SENC) magnetic resonance imaging at 3.0 Tesla

Objectives: To investigate whether subendocardial and transmural myocardial infarction can be identified and differentiated using the peak circumferential and longitudinal strains measured by fast strain-encoded (SENC). Methods: Nineteen patients with ischemic heart diseases underwent imaging with fast SENC and late gadolinium enhancement (LGE) MRI at 3T. Fast SENC measurements were performed in three short-axis slices (basal, mid-ventricular and apical levels) and one long-axis view (four-chamber) to assess peak longitudinal and circumferential systolic strains. Results: All patients showed myocardial infarction with an average of 7 positive LGE segments. A total of 304 segments for longitudinal strains (LS) and 114 segments for circumferential strains (CS) could be analysed. Positive LGE segments showed lower peak CS and LS compared with the no-LGE segments (P < 0.0001 for both). Segments with subendocardial infarction showed reduced CS and LS compared with the no-LGE segments (P < 0.0001 for both). There was a significant difference in CS between subendocardial and transmural infarct segments (P = 0.03), but no significant difference in LS between them (P = 0.64). Conclusions: Fast SENC can identify old myocardial infarction and differentiate subendocardial from transmural infarction

Volume change in infrapatellar fat pad is associated not with obesity but with cartilage degeneration

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Application of non-Gaussian water diffusional kurtosis imaging in the assessment of uterine tumors: A preliminary study - Fig 4

<p>Box-and-whisker plot of mean diffusivity (D) of uterine malignant tumor, leiomyoma, healthy myometrium, and healthy endometrium for (a) observer 1 and (b) observer 2. Outliers are also represented (° and *). The top and bottom of each box represent the 25th and 75th percentiles of the mean D, respectively. The horizontal line inside each box represents the median value. The graphs show a significantly lower mean D for uterine malignant tumor than for leiomyoma, healthy myometrium, and healthy endometrium. There were no significant differences in D between leiomyoma and endometrium (<i>P</i> = 0.74), or myometrium and endometrium (<i>P</i> = 0.21) for observer 1. There were no significant differences in D between leiomyoma and myometrium (<i>P</i> = 0.71), or leiomyoma and endometrium (<i>P</i> = 0.70) for observer 2.</p