Magnetic Resonance in Medical Sciences最新文献

{"title":"Evaluating Biliary Malignancy with Measured and Calculated Ultra-high b-value Diffusion-weighted MR Imaging at 3T.","authors":"Minkyeong Kim, Tae Young Lee, Byeong Seong Kang, Woon Jung Kwon, Soyeoun Lim, Gyeong Min Park, Minseo Bang","doi":"10.2463/mrms.mp.2022-0144","DOIUrl":"10.2463/mrms.mp.2022-0144","url":null,"abstract":"<p><strong>Purpose: </strong>Although diffusion-weighted imaging (DWI) with ultra-high b-values is reported to be advantageous in the detection of some tumors, its applicability is not yet known in biliary malignancy. Therefore, this study aimed to evaluate the impact of measured b = 1400 s/mm² (M1400) and calculated b = 1400 s/mm² (C1400) DWI on image quality and quality of lesion discernibility using a modern 3T MR system compared to conventional b = 800 s/mm² DWI (M800).</p><p><strong>Methods: </strong>We evaluated 56 patients who had pathologically proven biliary malignancy. All the patients underwent preoperative or baseline 3T MRI using DWI (b = 50, 400, 800, and 1400 s/mm²). The calculated DWI was obtained using a conventional DWI set (b = 50, 400, and 800). The tumor-to-bile contrast ratio (CR) and tumor SNR were compared between the different DWI images. Likert scores were given on a 5-point scale to assess the overall image quality, overall artifacts, ghost artifacts, misregistration artifacts, margin sharpness, and lesion discernibility. Repeated-measures analysis of variance with post hoc analyses was used for statistical evaluations.</p><p><strong>Results: </strong>The CR of the tumor-to-bile was significantly higher in both M1400 and C1400 than in M800 (P^a < 0.01). SNRs were significantly higher in M800, followed by C1400 and M1400 (P^a < 0.01). Lesion discernibility was significantly improved for M1400, followed by C1400 and M800 for both readers (P^a < 0.01).</p><p><strong>Conclusion: </strong>Using a 3T MRI, both measured and calculated DWI with an ultra-high b-value offer superior lesion discernibility for biliary malignancy compared to the conventional DWI.</p>","PeriodicalId":18119,"journal":{"name":"Magnetic Resonance in Medical Sciences","volume":" ","pages":"428-437"},"PeriodicalIF":2.5,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11447472/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9462855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"White and Gray Matter Abnormality in Burning Mouth Syndrome Evaluated with Diffusion Tensor Imaging and Neurite Orientation Dispersion and Density Imaging.","authors":"Shimpei Kato, Ryo Kurokawa, Fumio Suzuki, Shiori Amemiya, Takahiro Shinozaki, Daiki Takanezawa, Ryutaro Kohashi, Osamu Abe","doi":"10.2463/mrms.mp.2022-0099","DOIUrl":"10.2463/mrms.mp.2022-0099","url":null,"abstract":"<p><strong>Purpose: </strong>Burning mouth syndrome (BMS) is defined by a burning sensation or pain in the tongue or other oral sites despite the presence of normal mucosa on inspection. Both psychiatric and neuroimaging investigations have examined BMS; however, there have been no analyses using the neurite orientation dispersion and density imaging (NODDI) model, which provides detailed information of intra- and extracellular microstructures. Therefore, we performed voxel-wise analyses using both NODDI and diffusion tensor imaging (DTI) models and compared the results to better comprehend the pathology of BMS.</p><p><strong>Methods: </strong>Fourteen patients with BMS and 11 age- and sex-matched healthy control subjects were prospectively scanned using a 3T-MRI machine using 2-shell diffusion imaging. Diffusion tensor metrics (fractional anisotropy [FA], mean diffusivity [MD], axial diffusivity [AD], and radial diffusivity [RD]) and neurite orientation and dispersion index metrics (intracellular volume fraction [ICVF], isotropic volume fraction [ISO], and orientation dispersion index [ODI]) were retrieved from diffusion MRI data. These data were analyzed using tract-based spatial statistics (TBSS) and gray matter-based spatial statistics (GBSS).</p><p><strong>Results: </strong>TBSS analysis showed that patients with BMS had significantly higher FA and ICVF and lower MD and RD than the healthy control subjects (family-wise error [FWE] corrected P < 0.05). Changes in ICVF, MD, and RD were observed in widespread white matter areas. Fairly small areas with different FA were included. GBSS analysis showed that patients with BMS had significantly higher ISO and lower MD and RD than the healthy control subjects (FWE-corrected P < 0.05), mainly limited to the amygdala.</p><p><strong>Conclusion: </strong>The increased ICVF in the BMS group may represent myelination and/or astrocytic hypertrophy, and microstructural changes in the amygdala in GBSS analysis indicate the emotional-affective profile of BMS.</p>","PeriodicalId":18119,"journal":{"name":"Magnetic Resonance in Medical Sciences","volume":" ","pages":"204-213"},"PeriodicalIF":3.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11024709/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9205157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pathological Factors Affecting the R2* Values of the Kidney in Blood Oxygenation Level-dependent MR Imaging: A Retrospective Study.","authors":"Tomohiko Nishino, Kazuhiro Takahashi, Sayaka Ono, Masakazu Mimaki","doi":"10.2463/mrms.mp.2022-0140","DOIUrl":"10.2463/mrms.mp.2022-0140","url":null,"abstract":"<p><strong>Purpose: </strong>Despite the usefulness of blood oxygenation level-dependent (BOLD) MRI in assessing glomerulonephritis activity, its relationship with histological findings remains unclear. Because glomerulonephritis presents multiple complex injury patterns, analysis of each pattern is essential. We aimed to elucidate the relationship between the histological findings of the kidney and BOLD MRI findings in mesangial proliferative glomerulonephritis.</p><p><strong>Methods: </strong>Children under 16 years of age diagnosed with mesangial proliferative glomerulonephritis by kidney biopsy at our university hospital between January 2013 and September 2022 were included in this study. Cortical and medullary spin relaxation rate (R2*) values were measured using BOLD MRI at 3T within two weeks before and after the kidney biopsy. The R2* values, including the fluctuations with low-dose oxygen administration, were retrospectively examined in relation to the cortical (mesangial proliferation, endothelial cell proliferation, crescent, sclerosis, and fibrosis) and medullary findings (fibrosis).</p><p><strong>Results: </strong>Sixteen times kidney biopsies were performed for glomerulonephritis during the study period, and one patient was excluded because of comorbidities; the remaining 14 patients included six boys with a mean age of 11.9 ± 3.5 years at the BOLD examination. None of the patients had medullary fibrosis. Among the kidney tissue parameters, only sclerosis showed a significant correlation with R2* values: medulla with R2* values under atmospheric pressure (r = 0.53, P < 0.05) and cortex with the rate of change in R2* values with low-dose oxygen administration (r = -0.57, P < 0.03). In the multiple regression analysis, only sclerosis was an independent contributor to the change in R2* values with oxygen administration in the cortex (regression coefficient -0.109, P < 0.05).</p><p><strong>Conclusion: </strong>Since the R2* values reflect histological changes in the kidney, BOLD MRI may facilitate the evaluation of mesangial proliferative glomerulonephritis, potentially reducing the patient burden.</p>","PeriodicalId":18119,"journal":{"name":"Magnetic Resonance in Medical Sciences","volume":" ","pages":"153-160"},"PeriodicalIF":3.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11024711/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10681255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of Diffusion Time and Temperature on Restricted Diffusion Signal: A Phantom Study.","authors":"Hinako Oshiro, Junichi Hata, Daisuke Nakashima, Naoya Hayashi, Yawara Haga, Kei Hagiya, Daisuke Yoshimaru, Hideyuki Okano","doi":"10.2463/mrms.mp.2022-0103","DOIUrl":"10.2463/mrms.mp.2022-0103","url":null,"abstract":"<p><strong>Purpose: </strong>Diffusion MRI is a physical measurement method that quantitatively indicates the displacement of water molecules diffusing in voxels. However, there are insufficient data to characterize the diffusion process physically in a uniform structure such as a phantom. This study investigated the transitional relationship between structure scale, temperature, and diffusion time for simple restricted diffusion using a capillary phantom.</p><p><strong>Methods: </strong>We performed diffusion-weighted pulsed-gradient stimulated-echo acquisition mode (STEAM) MRI with a 9.4 Tesla MRI system (Bruker BioSpin, Ettlingen, Germany) and a quadrature coil with an inner diameter of 86 mm (Bruker BioSpin). We measured the diffusion coefficients (radial diffusivity [RD]) of capillary plates (pore sizes 6, 12, 25, 50, and 100 μm) with uniformly restricted structures at various temperatures (10ºC, 20ºC, 30ºC, and 40ºC) and multiple diffusion times (12-800 ms). We evaluated the characteristics of scale, temperature, and diffusion time for restricted diffusion.</p><p><strong>Results: </strong>The RD decayed and became constant depending on the structural scale. Diffusion coefficient fluctuations with temperature occurred mostly under conditions of a large structural scale and short diffusion time. We obtained data suggesting that temperature-dependent changes in the diffusion coefficients follow physical laws.</p><p><strong>Conclusion: </strong>No water molecules were observed outside the glass tubes in the capillary plates, and the capillary plates only reflected a restricted diffusion process within the structure.We experimentally evaluated the characteristics of simple restricted diffusion to reveal the transitional relationship of the diffusion coefficient with diffusion time, structure scale, and temperature through composite measurement.</p>","PeriodicalId":18119,"journal":{"name":"Magnetic Resonance in Medical Sciences","volume":" ","pages":"136-145"},"PeriodicalIF":3.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11024708/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10681256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thin-slice Two-dimensional T2-weighted Imaging with Deep Learning-based Reconstruction: Improved Lesion Detection in the Brain of Patients with Multiple Sclerosis.","authors":"Masatoshi Iwamura, Satoru Ide, Kenya Sato, Akihisa Kakuta, Soichiro Tatsuo, Atsushi Nozaki, Tetsuya Wakayama, Tatsuya Ueno, Rie Haga, Misako Kakizaki, Yoko Yokoyama, Ryoichi Yamauchi, Fumiyasu Tsushima, Koichi Shibutani, Masahiko Tomiyama, Shingo Kakeda","doi":"10.2463/mrms.mp.2022-0112","DOIUrl":"10.2463/mrms.mp.2022-0112","url":null,"abstract":"<p><strong>Purpose: </strong>Brain MRI with high spatial resolution allows for a more detailed delineation of multiple sclerosis (MS) lesions. The recently developed deep learning-based reconstruction (DLR) technique enables image denoising with sharp edges and reduced artifacts, which improves the image quality of thin-slice 2D MRI. We, therefore, assessed the diagnostic value of 1 mm-slice-thickness 2D T2-weighted imaging (T2WI) with DLR (1 mm T2WI with DLR) compared with conventional MRI for identifying MS lesions.</p><p><strong>Methods: </strong>Conventional MRI (5 mm T2WI, 2D and 3D fluid-attenuated inversion recovery) and 1 mm T2WI with DLR (imaging time: 7 minutes) were performed in 42 MS patients. For lesion detection, two neuroradiologists counted the MS lesions in two reading sessions (conventional MRI interpretation with 5 mm T2WI and MRI interpretations with 1 mm T2WI with DLR). The numbers of lesions per region category (cerebral hemisphere, basal ganglia, brain stem, cerebellar hemisphere) were then compared between the two reading sessions.</p><p><strong>Results: </strong>For the detection of MS lesions by 2 neuroradiologists, the total number of detected MS lesions was significantly higher for MRI interpretation with 1 mm T2WI with DLR than for conventional MRI interpretation with 5 mm T2WI (765 lesions vs. 870 lesions at radiologist A, < 0.05). In particular, of the 33 lesions in the brain stem, radiologist A detected 21 (63.6%) additional lesions by 1 mm T2WI with DLR.</p><p><strong>Conclusion: </strong>Using the DLR technique, whole-brain 1 mm T2WI can be performed in about 7 minutes, which is feasible for routine clinical practice. MRI with 1 mm T2WI with DLR enabled increased MS lesion detection, particularly in the brain stem.</p>","PeriodicalId":18119,"journal":{"name":"Magnetic Resonance in Medical Sciences","volume":" ","pages":"184-192"},"PeriodicalIF":3.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11024714/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9180524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Physical Exercise Alters Egress Pathways for Intrinsic CSF Outflow: An Investigation Performed with Spin-labeling MR Imaging.","authors":"Mitsue Miyazaki, Vadim Malis, Asako Yamamoto, Jirach Kungsamutr, Linda K McEvoy, Marin A McDonald, Won C Bae","doi":"10.2463/mrms.mp.2023-0005","DOIUrl":"10.2463/mrms.mp.2023-0005","url":null,"abstract":"<p><strong>Purpose: </strong>Cerebrospinal fluid (CSF) clearance is essential for maintaining a healthy brain and cognition by removal of metabolic waste from the central nervous system. Physical exercise has been shown to improve human health; however, the effect of physical exercise on intrinsic CSF outflow in humans remains unexplored. The purpose of this study was to investigate intrinsic CSF outflow pathways and quantitative metrics of healthy individuals with active and sedentary lifestyles. In addition, the effect of exercise was investigated among the sedentary subjects before and after 3 weeks of physical activity.</p><p><strong>Methods: </strong>This study was performed on 18 healthy adults with informed consent, using a clinical 3-Tesla MRI scanner. We classified participants into two groups based on reported time spent sitting per day (active group: < 7 hours sitting per day and sedentary group: ≥ 7 hours sitting per day). To elucidate the effect of exercise, sedentary individuals increased their activity to 3.5 hours for 3 weeks.</p><p><strong>Results: </strong>We show that there are two intrinsic CSF egress pathways of the dura mater and lower parasagittal dura (PSD). The adults with an active lifestyle had greater intrinsic CSF outflow metrics than adults with a more sedentary lifestyle. However, after increased physical activity, the sedentary group showed improved CSF outflow metrics. This improvement was particularly notable at the lower PSD, where outflow metrics were highest among the active group.</p><p><strong>Conclusion: </strong>Our findings describe the relationship between physical activity and intrinsic CSF outflow and show a potential selective outflow pathway with increasing physical activity in the lower PSD pathway, potentially from the perivascular space or cortical venous subpial space.</p>","PeriodicalId":18119,"journal":{"name":"Magnetic Resonance in Medical Sciences","volume":" ","pages":"171-183"},"PeriodicalIF":3.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11024710/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9092522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Deep Learning Reconstruction on Respiratory-triggered T2-weighted MR Imaging of the Liver: A Comparison between the Single-shot Fast Spin-echo and Fast Spin-echo Sequences.","authors":"Kengo Kiso, Takahiro Tsuboyama, Hiromitsu Onishi, Kazuya Ogawa, Atsushi Nakamoto, Mitsuaki Tatsumi, Takashi Ota, Hideyuki Fukui, Keigo Yano, Toru Honda, Shinji Kakemoto, Yoshihiro Koyama, Hiroyuki Tarewaki, Noriyuki Tomiyama","doi":"10.2463/mrms.mp.2022-0111","DOIUrl":"10.2463/mrms.mp.2022-0111","url":null,"abstract":"<p><strong>Purpose: </strong>To compare the effects of deep learning reconstruction (DLR) on respiratory-triggered T2-weighted MRI of the liver between single-shot fast spin-echo (SSFSE) and fast spin-echo (FSE) sequences.</p><p><strong>Methods: </strong>Respiratory-triggered fat-suppressed liver T2-weighted MRI was obtained with the FSE and SSFSE sequences at the same spatial resolution in 55 patients. Conventional reconstruction (CR) and DLR were applied to each sequence, and the SNR and liver-to-lesion contrast were measured on FSE-CR, FSE-DLR, SSFSE-CR, and SSFSE-DLR images. Image quality was independently assessed by three radiologists. The results of the qualitative and quantitative analyses were compared among the four types of images using repeated-measures analysis of variance or Friedman's test for normally and non-normally distributed data, respectively, and a visual grading characteristics (VGC) analysis was performed to evaluate the image quality improvement by DLR on the FSE and SSFSE sequences.</p><p><strong>Results: </strong>The liver SNR was lowest on SSFSE-CR and highest on FSE-DLR and SSFSE-DLR (P < 0.01). The liver-to-lesion contrast did not differ significantly among the four types of images. Qualitatively, noise scores were worst on SSFSE-CR but best on SSFSE-DLR because DLR significantly reduced noise (P < 0.01). In contrast, artifact scores were worst both on FSE-CR and FSE-DLR (P < 0.01) because DLR did not reduce the artifacts. Lesion conspicuity was significantly improved by DLR compared with CR in the SSFSE (P < 0.01) but not in FSE sequences for all readers. Overall image quality was significantly improved by DLR compared with CR for all readers in the SSFSE (P < 0.01) but only one reader in the FSE (P < 0.01). The mean area under the VGC curve values for the FSE-DLR and SSFSE-DLR sequences were 0.65 and 0.94, respectively.</p><p><strong>Conclusion: </strong>In liver T2-weighted MRI, DLR produced more marked improvements in image quality in SSFSE than in FSE.</p>","PeriodicalId":18119,"journal":{"name":"Magnetic Resonance in Medical Sciences","volume":" ","pages":"214-224"},"PeriodicalIF":3.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11024712/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9205156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Breath-hold High-resolution T1-weighted Gradient Echo Liver MR Imaging with Compressed Sensing Obtained during the Gadoxetic Acid-enhanced Hepatobiliary Phase: Image Quality and Lesion Visibility Compared with a Standard T1-weighted Sequence.","authors":"Kenichiro Ihara, Hideko Onoda, Masahiro Tanabe, Etsushi Iida, Takaaki Ueda, Taiga Kobayashi, Mayumi Higashi, Marcel Dominik Nickel, Hiroshi Imai, Katsuyoshi Ito","doi":"10.2463/mrms.mp.2022-0137","DOIUrl":"10.2463/mrms.mp.2022-0137","url":null,"abstract":"<p><strong>Purpose: </strong>To evaluate the feasibility of breath-hold (BH) high-resolution (HR) T1-weighted gradient echo hepatobiliary phase (HBP) imaging using compressed sensing (CS) in gadoxetic acid-enhanced liver MRI in comparison with standard HBP imaging using parallel imaging (PI).</p><p><strong>Methods: </strong>The study included 122 patients with liver tumors with hypointensity in the HBP who underwent both HR HBP imaging with CS and standard HBP imaging with PI. Two radiologists evaluated the liver edge sharpness, hepatic vessel conspicuity, bile duct conspicuity, image noise, and overall image quality, as well as the lesion conspicuity on HR and standard HBP imaging and the contrast-enhanced (CE) MR cholangiography (MRC) image quality reconstructed from HBP images. As a quantitative analysis, the SNR of the liver and the liver to lesion signal intensity ratio (LLSIR) were also determined.</p><p><strong>Results: </strong>The liver edge sharpness, hepatic vessel conspicuity, bile duct conspicuity, and overall image quality as well as the lesion conspicuity and the LLSIR on HR HBP imaging with CS were significantly higher than those on standard HBP imaging (all of P < 0.001). The image quality of CE-MRC reconstructed from HR HBP imaging with CS was also significantly higher than that from standard HBP imaging (P < 0.001). Conversely, the SNR of liver in standard HBP was significantly higher than that in HR HBP with CS (P < 0.001).</p><p><strong>Conclusion: </strong>BH HR HBP imaging with CS provided an improved overall image quality, lesion conspicuity, and CE-MRC visualization when compared with standard HBP imaging without extending the acquisition time.</p>","PeriodicalId":18119,"journal":{"name":"Magnetic Resonance in Medical Sciences","volume":" ","pages":"146-152"},"PeriodicalIF":3.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11024715/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9221470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimal Protocol for Contrast-enhanced Free-running 5D Whole-heart Coronary MR Angiography at 3T.","authors":"Masaki Ishida, Jérôme Yerly, Haruno Ito, Masafumi Takafuji, Shiro Nakamori, Shinichi Takase, Yoshito Ichiba, Yoshiaki Komori, Kaoru Dohi, Davide Piccini, Jessica A M Bastiaansen, Matthias Stuber, Hajime Sakuma","doi":"10.2463/mrms.tn.2022-0086","DOIUrl":"10.2463/mrms.tn.2022-0086","url":null,"abstract":"<p><p>Free-running 5D whole-heart coronary MR angiography (MRA) is gaining in popularity because it reduces scanning complexity by removing the need for specific slice orientations, respiratory gating, or cardiac triggering. At 3T, a gradient echo (GRE) sequence is preferred in combination with contrast injection. However, neither the injection scheme of the gadolinium (Gd) contrast medium, the choice of the RF excitation angle, nor the dedicated image reconstruction parameters have been established for 3T GRE free-running 5D whole-heart coronary MRA. In this study, a Gd injection scheme, RF excitation angles of lipid-insensitive binominal off-resonance RF excitation (LIBRE) pulse for valid fat suppression and continuous data acquisition, and compressed-sensing reconstruction regularization parameters were optimized for contrast-enhanced free-running 5D whole-heart coronary MRA using a GRE sequence at 3T. Using this optimized protocol, contrast-enhanced free-running 5D whole-heart coronary MRA using a GRE sequence is feasible with good image quality at 3T.</p>","PeriodicalId":18119,"journal":{"name":"Magnetic Resonance in Medical Sciences","volume":" ","pages":"225-237"},"PeriodicalIF":3.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11024717/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10567397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aliphatic and Olefinic Fat Suppression in the Orbit Using Polarity-altered Spectral and Spatial Selective Acquisition (PASTA) with Opposed Phase.","authors":"Vadim Malis, Won C Bae, Asako Yamamoto, Yoshimori Kassai, Marin A McDonald, Mitsue Miyazaki","doi":"10.2463/mrms.mp.2022-0073","DOIUrl":"10.2463/mrms.mp.2022-0073","url":null,"abstract":"<p><strong>Purpose: </strong>Fatty acid composition of the orbit makes it challenging to achieve complete fat suppression during orbit MR imaging. Implementation of a fat suppression technique capable of suppressing signals from saturated (aliphatic) and unsaturated (olefinic or protons at double-bonded carbon sites) fat would improve the visualization of an optical nerve. Furthermore, the ability to semi-quantify the fractions of aliphatic and olefinic fat may potentially provide valuable information in assessing orbit pathology.</p><p><strong>Methods: </strong>A phantom study was conducted on various oil samples on a clinical 3 Tesla scanner. The imaging protocol included three 2D fast spin echo (FSE) sequences: in-phase, polarity-altered spectral and spatial selective acquisition (PASTA), and a combination of PASTA with opposed phase in olefinic and aliphatic chemical shift. The results were validated against high-resolution 11.7T NMR and compared with images acquired with spectral attenuated inversion recovery (SPAIR) and chemical shift selective (CHESS) fat suppression techniques. In-vivo data were acquired on eight healthy subjects and were compared with the prior histological studies.</p><p><strong>Results: </strong>PASTA with opposed phase achieved complete suppression of fat signals in the orbits and provided images of well-delineated optical nerves and muscles in all subjects. The olefinic fat fraction in the olive, walnut, and fish oil phantoms at 3T was found to be 5.0%, 11.2%, and 12.8%, respectively, whereas 11.7T NMR provides the following olefinic fat fractions: 6.0% for olive, 11.5% for walnut, and 12.6% for fish oils. For the in-vivo study, on average, olefinic fat accounted for 9.9% ± 3.8% of total fat while the aliphatic fat fraction was 90.1% ± 3.8%, in the normal orbits.</p><p><strong>Conclusion: </strong>We have introduced a new fat suppression technique using PASTA with opposed phase and applied it to human orbits. The purposed method achieves an excellent orbital fat suppression and the quantification of aliphatic and olefinic fat signals.</p>","PeriodicalId":18119,"journal":{"name":"Magnetic Resonance in Medical Sciences","volume":" ","pages":"193-203"},"PeriodicalIF":3.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11024719/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9154455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}