||Takayama, Yukihisa; Nishie, Akihiro; Togao, Osamu; Asayama, Yoshiki; Ishigami, Kousei; Ushijima, Yasuhiro; Okamoto, Daisuke; Fujita, Nobuhiro; Sonoda, Kenzo; Hida, Tomoyuki; Ohishi, Yoshihiro; Keupp, Jochen; Honda, Hiroshi, Amide Proton Transfer MR Imaging of Endometrioid Endometrial Adenocarcinoma: Association with Histologic Grade, RADIOLOGY, 10.1148/radiol.2017170349, 286, 3, 929-937, 2018.03.
||Takayama Y, Nishie A, Asayama Y, Ishigami K, Kakihara D, Ushijima Y, Fujita N, Shirabe K, Takemura A, Honda H., Image quality and diagnostic performance of free-breathing diffusion-weighted imaging for hepatocellular carcinoma., World J Hepatol., 18, 9(4), 657-666, 2017.05.
||Takayama, Yukihisa; Nishie, Akihiro; Sugimoto, Masaaki; Togao, Osamu; Asayama, Yoshiki; Ishigami, Kousei; Ushijima, Yasuhiro; Okamoto, Daisuke; Fujita, Nobuhiro; Yokomizo, Akira; Keupp, Jochen; Honda, Hiroshi, Amide proton transfer (APT) magnetic resonance imaging of prostate cancer: comparison with Gleason scores, MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE, 10.1007/s10334-016-0537-4, 29, 4, 671-679, 2016.08.
||Takayama, Yukihisa; Nishie, Akihiro; Asayama, Yoshiki; Ishigami, Kousei; Kakihara, Daisuke; Uhijima, Yasuhiro; Fujita, Nobuhiro; Yoshiura, Takashi; Takemura, Atsushi; Obara, Makoto; Takahara, Taro; Honda, Hiroshi, Optimization and Clinical Feasibility of Free-breathing Diffusion-weighted Imaging of the Liver: Comparison with Respiratory-Triggered Diffusion-weighted Imaging, MAGNETIC RESONANCE IN MEDICAL SCIENCES, 10.2463/mrms.2014-0032, 14, 2, 123-132.
||Yukihisa Takayama, Akihiro Nishie, Yoshiki Asayama, Yasuhiro Ushijima, Daisuke Okamoto, Nobuhiro Fujita, Koichiro Morita, Ken shirabe, Kazuhiro Kotoh, Yuichiro Kubo, Tomoyuki Okuaki, Hiroshi Honda, T1 ρ Relaxation of the liver: A potential biomarker of liver function., JOURNAL OF MAGNETIC RESONANCE IMAGING, 42, 1, 188-195, 2015.07.
||Takayama, Yukihisa; Nishie, Akihiro; Asayama, Yoshiki; Ushijima, Yasuhiro; Fujita, Nobuhiro; Shimamoto, Dai; Yoshiura, Takashi; Obara, Makoto; Takemura, Atsushi; Yoneyama, Masami; Honda, Hiroshi, Three-Dimensional T2-Weighted Imaging for Liver MRI: Clinical Values of Tissue-Specific Variable Refocusing Flip-Angle Turbo Spin Echo Imaging, JOURNAL OF MAGNETIC RESONANCE IMAGING, 10.1002/jmri.24554, 41, 2, 339-346, 2015.02.
||Yukihisa Takayama, Masamitsu Hatakenaka, Hidetoshi Tsushima, KEN OKAZAKI, Takashi Yoshiura, Masato Yonezawa, Yukihide Iwamoto, Hiroshi Honda, T1ρ is superior to T2 mapping for the evaluation of articular cartilage denaturalization with osteoarthritis: Radiological-pathological correlation after total knee arthroplasty., European Journal of Radiology, 82, 4, e192-e198, 2013.04.
||Yukihisa Takayama, Akihiro Nishie, Asayama Yoshiki, Kousei Ishigami, Yasuhiro Ushijima, Fujita Nobuhiro, Hiroshi Honda, Hypovascular hepatic nodule showing hypointensity in the hepatobiliary phase of gadoxetic acid-enhanced MRI in patients with chronic liver disease: prediction of malignant transformation., European Journal of Radiology, 81, 11, 3072-3078, 2012.11.
||Yukihisa Takayama, Akihiro Nishie, Asayama Yoshiki, Kousei Ishigami, Fujita Nobuhiro, Yasuhiro Ushijima, Takashi Yoshiura, Masakazu Hirakawa, Hiroshi Honda, Image quality of Gd-EOB-DTPA-enhanced magnetic resonance imaging of the liver using dual-source parallel radiofrequency transmission technology: Comparison with the post-processing correction method for B1 inhomogeneity-induced signal loss., European Journal of Radiology, 81, 11, 3035-3040, 2012.11.
||Yukihisa Takayama, Takashi Yoshiura, Akihiro Nishie, Tomohiro Nakayama, Masamitsu Hatakenaka, Naoki Kato, Satoshi Yoshise, Jochen Keupp,Dirk Burdinski, and Hiroshi Honda
, Ytterbium-based PARACEST agent: feasibility of CEST imaging on a clinical MR scanner., Magnetic Resonance in Medical Sciences, 11, 1, 35-41, 2012.03, Purpose: We investigated the feasibility of performing chemical exchange saturation transfer (CEST) imaging using ytterbium-based paramagnetic CEST (PARACEST) agents on a clinical magnetic resonance (MR) scanner.
Materials and Methods: We prepared solutions of 3 different ytterbium-based PARACEST agents at concentrations of 5, 10, 20, and 50 mM at a pH of 7.4 and at a concentration of 50 mM at pHs of 3.0, 5.0, 7.4, and 9.5. We acquired images with a turbo spin echo technique using a quadrature head coil and a clinical 3.0-tesla MR system in accordance with the safety limits of the specific absorption rate (SAR). We acquired CEST images with presaturation offset frequencies from -5,000 Hz (-39.1 ppm) to 5,000 Hz (39.1 ppm) with an interval of 500 Hz (3.9 ppm) for each condition. We repeated each scan 3 times and then calculated the mean and standard deviations of the magnitude of the CEST effect at different concentrations and pH values for each agent. We used one-way analysis of variance and Tukey's honestly significant difference post hoc test to compare mean values of the magnitude of the CEST effect obtained at different concentrations and pH values. P < 0.05 was considered significant.
Results: PARACEST agents showed a strong CEST effect at their specific presaturation offset frequencies. For each agent, the CEST effect showed significant concentration dependency (P < 0.05), increasing with agent concentration, and significant pH dependency (P < 0.05), with strong effect near physiological pH.
Conclusion: CEST imaging using ytterbium-based PARACEST agents might be feasible on a clinical MR scanner with further modifications, such as adjustments of the presaturation radiofrequency pulse and imaging protocols..
||Akihiro Nishie, Yasuhiro Ushijima, Tsuyoshi Tajima, Asayama Yoshiki, Kousei Ishigami, Yukihisa Takayama, Daisuke Okamoto, 柿原 大輔, Kengo Yoshimitsu, Koichiro Abe, Hiroshi Honda, Quantitative analysis of liver function using superparamagnetic iron oxide- and Gd-EOB-DTPA-enhanced MRI: comparison with Technetium-99m galactosyl serum albumin scintigraphy, European Journal of Radiology, 81, 6, 1100-1104, 2012.06.
||Asayama Yoshiki, Akihiro Nishie, Kousei Ishigami, 柿原 大輔, Yasuhiro Ushijima, Yukihisa Takayama, Fujita Nobuhiro, Tsuyoshi Tajima, Hiroshi Honda, Kengo Yoshimitsu, Yukihide Iwamoto, CT-guided radiofrequency ablation of osteoid osteoma in the long bones of the lower extremity., World Journal of Radiology, 4, 6, 278-282, 2012.06.
||Akihiro Nishie, Kengo Yoshimitsu, Daisuke Okamoto, Tsuyoshi Tajima, Asayama Yoshiki, Kousei Ishigami, Yasuhiro Ushijima, Yukihisa Takayama, Fujita Nobuhiro, Ken Shirabe, Hiroshi Honda, CT prediction of histological grade of hypervascular hepatocellular carcinoma: utility of the portal phase., Japanese Journal of Radiology, 31, 2, 89-98, 2013.02.
||Akihiro Nishie, Asayama Yoshiki, Kousei Ishigami, Tsuyoshi Tajima, Yasuhiro Ushijima, Yukihisa Takayama, Fujita Nobuhiro, Ken Shirabe, Hiroshi Honda, MR prediction of liver fibrosis using a liver-specific contrast agent: Superparamagnetic iron oxide versus Gd-EOB-DTPA.
, Journal of Magnetic Resonance Imaging, 36, 3, 664-671, 2012.09.
||Nishie A, Ushijima Y, Tajima T, Asayama Y, Ishigami K, Kakihara D, Nakayama T, Takayama Y, Okamoto D, Abe K, Obara M, Yoshimitsu K, Honda H., Quantitative analysis of liver function using superparamagnetic iron oxide- and Gd-EOB-DTPA-enhanced MRI: Comparison with Technetium-99m galactosyl serum albumin scintigraphy., European Journal of Radiology, 81, 6, 1100-1104, 2012.01, PURPOSE: To examine whether or not the parameters regarding the signal intensity of the liver parenchyma on superparamagnetic iron oxide (SPIO)- and gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI are correlated with the parameters of Technetium-99m galactosyl serum albumin ((99m)Tc-GSA) scintigraphy.
MATERIALS AND METHODS: This retrospective study consisted of 55 and 33 patients who underwent SPIO- and Gd-EOB-DTPA-enhanced MRI in addition to (99m)Tc-GSA scintigraphy, respectively. For each patient, we calculated Pre R2* and Pre R2, which are equivalent to R2* (=1/T2*) and R2 (=1/T2) values of the liver parenchyma; ΔR2* and ΔR2, which represent differences in R2* and R2 values of the liver parenchyma before and after administration of SPIO; and the increase rates of both the liver-to-spleen signal intensity ratio (LSR) and the liver-to-major psoas muscle signal intensity ratio (LMR) on the hepatobiliary phase compared with the precontrast image. For (99m)Tc-GSA scintigraphy, the receptor index LHL15 and the blood clearance index HH15 were recorded.
RESULTS: Regression analysis showed a moderate correlation between Pre R2* and LHL15 (P<0.05). Mild to moderate correlations were also obtained between any combination of ΔR2* and ΔR2 on the one hand, and LHL15 and HH15 on the other (P<0.05). There were moderate correlations between any combination of increase rates of LSR and LMR on the one hand, and LHL15 and HH15 on the other (P<0.05-0.001).
CONCLUSION: Pre R2*, ΔR2*, ΔR2 and the increase rates of LSR and LMR could be used as quantitative indicators of liver function.
||Tsushima H, Okazaki K, Takayama Y, Hatakenaka M, Honda H, Izawa T, Nakashima Y, Yamada H, Iwamoto Y., Evaluation of cartilage degradation in arthritis using T1ρ magnetic resonance imaging mapping., Rheumatol International, 2011.09, T1ρ magnetic resonance imaging (MRI) can be used to map proteoglycan (PG) loss in cartilage. Here, we used T1ρ MRI to map cartilage degradation in osteoarthritis (OA) and rheumatoid arthritis (RA). Tissue samples were obtained from five RA patients and 14 OA patients following total knee arthroplasty (TKA). Three parameters were measured: First, macroscopic grading of cartilage sample tissues was performed on a 5-grade scale (G0: normal, G1: swelling, G2: superficial fibrillation, G3: deep fibrillation, G4: subchondral bone exposure). Second, semi-quantitative values of PG were assessed by measuring the optical density of Safranin-O-stained paraffin sections that had been digitally photographed. Third, cartilage was divided into superficial and deep layers and the T1ρ values were quantified. T1ρ values of OA and RA in the superficial layers showed significant differences between groups (G0/1 and G0/2 for OA; G0/2 and G1/2 for RA). In the deep layers, T1ρ values of OA and RA also differed significantly between groups. In both the superficial and deep layers, there was a significant correlation between the mean T1ρ values and macroscopic grading (P < 0.01 for OA, P < 0.001 for RA). We found a negative correlation between the score of Safranin-O staining and T1ρ values (r = -0.61 for OA, r = -0.79 for RA). In addition, RA subjects had significantly higher T1ρ values than OA subjects of similar morphologic grade. In conclusion, T1ρ MRI is able to detect and map the early stages of cartilage degradation in OA and RA. This method is reliable and useful for the evaluation of macromolecular changes in arthritic cartilage..
||Jia G, Takayama Y, Flanigan DC, Kaeding CC, Zhou J, Chaudhari A, Clark D, Sammet S, Liang J, Choi S, Knopp MV., Quantitative assessment of mobile protein levels in human knee synovial fluid: feasibility of chemical exchange saturation transfer (proteinCEST) MRI of osteoarthritis, Magnetic Resonance Imaging, 29, 3, 335-341, 2011.04, PURPOSE: To establish the feasibility of chemical exchange saturation transfer (proteinCEST) MRI in the differentiation of osteoarthritis (OA) knee joints from non-OA joints by detecting mobile protein and peptide levels in synovial fluid by determining their relative distribution.
MATERIALS AND METHODS: A total of 25 knees in 11 men and 12 women with knee injuries were imaged using whole knee joint proteinCEST MRI sequence at 3 T. The joint synovial fluid was segmented and the asymmetric magnetization transfer ratio at 3.5 ppm MTR(asym) (3.5 ppm) was calculated to assess protein content in the synovial fluid. The 85th percentile of synovial fluid MTR(asym) (3.5 ppm) distribution profile was compared using the independent Student's t test. The diagnostic performance of the 85th percentile of synovial fluid MTR(asym) (3.5 ppm) in differentiating OA and non-OA knee joints was evaluated.
RESULTS: The 85th percentile of synovial fluid MTR(asym) (3.5 ppm) in knee joints with OA was 8.6%±3.4% and significantly higher than that in the knee joints without OA (6.3%±1.4%, P<.05). A knee joint with an 85th percentile of synovial fluid MTR(asym) (3.5 ppm) greater than 7.7% was considered to be an OA knee joint. With the threshold, the sensitivity, specificity and overall accuracy for differentiating knee joints with OA from the joints without OA were 54% (7/13), 92% (11/12) and 72% (18/25), respectively.
CONCLUSION: proteinCEST MRI appears feasible as a quantitative methodology to determine mobile protein levels in synovial fluid and identify patterns characteristic for OA disease.