九州大学 研究者情報
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筑井 徹(ちくい とおる) データ更新日:2019.12.19

准教授 /  歯学研究院 歯学部門 顎顔面病態学講座


主な研究テーマ
複数b値の拡散強調像の新しいモデル解析
キーワード:拡散強調画像、統計学的モデル
2019.04~2021.04.
頭頸部のMRI造影剤分布の解析
キーワード:MRI造影剤、頭頸部
2006.03~2016.04.
咀嚼筋のMRI
キーワード:MRI, 拡散、ADC, トラクトグラフィー
2009.04~2012.03.
MRIによる頭頸部臓器ののT1,T2,ADC 算出, 拡散パラメーターの推定
キーワード:MRI, T1値、T2値、ADC
2006.04.
頸部リンパ節の早期検出
キーワード:頸部リンパ節、画像診断
1998.04~2003.12.
研究業績
主要原著論文
1. WannakamonPanyarak, Toru Chiku, Yasuo Yamashita, Takeshi Kamitani, Kazunori Yoshiura., Image Quality and ADC Assessment in Turbo Spin-Echo and Echo-Planar Diffusion-Weighted MR Imaging of Tumors of the Head and Neck, Academic Radiology, https://doi.org/10.1016/j.acra.2018.11.016, 2018.12, Rationale and Objectives

We aimed to compare the distortion ratio (DR), signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) between turbo spin-echo (TSE)-diffusion-weighted imaging (DWI) and echo-planar imaging (EPI)-DWI of the orofacial region and prove the usefulness of TSE-DWI for the differential diagnosis of orofacial lesions.
Materials and methods

The DR, SNR, and CNR of both sequences were compared in 42 cases. Then, the apparent diffusion coefficient (ADC) of various orofacial lesions obtained by TSE-DWI was investigated in 143 lesions.
Results

In the first study, 38 of 42 cases were analyzed. TSE-DWI showed a significantly lower DR (p < 0.05) and higher SNR and CNR than EPI-DWI (p < 0.05), indicating the superiority of TSE-DWI. In the second study, 114 cases (79.3%) were successfully analyzed. When lesions were divided into cysts, benign tumors, squamous cell carcinoma, malignant lymphoma, and other malignant tumors (OT), significant differences were observed in all pairs of lesions (p < 0.05) except squamous cell carcinoma and OT (p = 0.877). The area under the curve for distinguishing benign from malignant tumors was 0.80 with a cutoff ADC of 1.29 × 10-3 mm²/s.
Conclusion

TSE-DWI produced better quality images than EPI-DWI. TSE-DWI yields the high possibility of obtaining ADC in the orofacial region, and this value was considered useful for the differential diagnosis of orofacial lesions..
2. Chikui T, Yamashita Y, Kise Y, Saito T, Okamura K, Yoshiura KBr J Radiol.., Estimation of proton density fat fraction of the salivary gland., Br J Radiol, doi: 10.1259/bjr.20170671., 91, 1085, 2018.05, OBJECTIVE:
Our first objective was to prove the validity of the six-point Dixon method for estimating the proton density fat fraction (PDFF) of the salivary gland. The second objective was to estimate the salivary gland PDFF using Dixon method to evaluate the pathological conditions.
METHODS:
At first, 12 volunteers underwent two types of sequences: single-voxel magnetic resonance spectroscopy and the Dixon method and the PDFFs obtained by the two methods were compared. Next, a total of 67 individuals [normal, n = 46; Sjögren's syndrome (SS), n = 11; and IgG4-related dacryoadenitis and sialadenitis (IgG4-DS), n = 4, parotitis, n = 6] were enrolled to estimate the parotid gland (PG) and submandibular gland (SMG) PDFF using the Dixon method.
RESULTS:
This volunteer study demonstrated excellent correlation between two methods (R2 = 0.964, slope = 1.05). In the normal group, the PG-PDFF was correlated with the weight and body mass index (BMI) (ρ = 0.38, p = 0.0085; and ρ = 0.63, p < 0.0001). The SMG-PDFF was also correlated with the weight, BMI, and serum triglyceride (ρ = 0.37, p = 0.0067; ρ = 0.42, p = 0.0022; and ρ = 0.35, p = 0.024). The PG-PDFF of the SS group (48.2 ± 15.1%) was higher than that of any other groups; however, no significant difference was found due to the wide overlap. The SS group (39.0 ± 26.14%) also had significantly higher SMG-PDFF than the normal group (8.9 ± 5.4%), p < 0.0001) and IgG4-DS group (3.8 ± 2.3%), p = 0.020).
CONCLUSION:
The Dixon method is a feasible method for estimating the PDFF and demonstrates fat accumulation in SMG in the SS group. Advances in knowledge: The PDFF obtained by the Dixon method is helpful for understanding the salivary gland pathological condition..
3. Yoshitaka Kise, Toru Chikui, Yasuo Yamashita, Kouji Kobayashi, Kazunori Yoshiura, Clinical usefulness of the mDIXON Quant the method for estimation of the salivary gland fat fraction: Comparison with MR spectroscopy., Br J Radiol., doi.org/10.1259/bjr.20160704, 2017.07, To estimate the fat fraction (FF) in the salivary glands (SGs) by the mDIXON method and the MRS method, and to compared the results.
METHODS:
Sixteen healthy volunteers were enrolled. mDIXON Quant and MRS (point-resolved spectroscopy: PRESS) with a single TE were employed to measure the FF in the parotid gland (PG) and submandibular gland (SMG). Multiple TEs were applied in 10 volunteers to correct for T2 decay. In addition, we assumed that the 1.3 ppm peak accounted for 60% of the total fat peak and estimated the FF (MRS all) as a gold standard. On mDIXON Quant images, VOIs were set on the bilateral SGs and we obtained the FF (mDIXON) of each VOI.
RESULTS:
There was a strong correlation between the results of the mDIXON Quant method and the MRS (single TE) method (R2=0.960, slope=0.900). Using PRESS with multiple TEs, there was also a strong correlation between FF (mDIXON) and FF (MRS all) (R2=0.963, slope=1.18). FF (MRS all) was 24.9 ± 12.7% in the PG and 4.5 ± 3.0% in the SMG, while FF (mDIXON) was 29.4 ± 16.2% in the PG and 6.4 ± 4.7% in the SMG. There were no significant differences between the two methods, but the Bland-Altman plot showed that FF (mDIXON) was slightly larger than FF (MRS all) for small FF areas.
CONCLUSIONS:
The mDIXON Quant method could be clinically useful for evaluating the FF of SGs, but the absolute values need careful interpretation Advance in knowledge: This study suggested the potential clinical usefulness of the mDIXON Quant method for the SGs..
4. Toru Chiikui, Erina KItamoto, Yukiko Nishioka Kami, Shintaro Kawano, Kouji Kobayashi, Takeshi Kamitani, Makoto Obara, Kazunori Yoshiura, Dynamic contrast-enhanced MRI of oral squamous cell carcinoma: A preliminary study of the correlations between quantitative parameters and the clinical stage., Br J Radiol., org/10.1259/bjr.20140814, 2015.04, To probe the utility of dynamic contrast-enhanced (DCE) -MRI parameters in assessing the clinical characteristics of oral squamous cell carcinoma.
METHODS:
A total of 85 tumors were included. We applied the Tofts and Kermode model for the DCE-MRI data, and obtained three dependent parameters: the influx forward volume transfer constant into the extravascular extracellular space (EES) from the plasma (Ktrans), the fractional volume of EES per unit volume of tissue (ve) and the fractional volume of plasma (vp). We evaluated the correlations between these parameters and the clinical stages.
RESULTS:
The T stage showed a negative correlation with the Ktrans (r = -0.2272, P = 0.0365), but it did not show a significant correlation with the other parameters. The N stage showed a negative correlation with Ktrans (r = -0.1948, P = 0.0404), and there were significant differences between N1 and N2+3 (0.119±0.027 min-1 vs 0.096±0.023 min-1, P = 0.0198) and between N0 and N2+3 (0.114±0.29 min-1 vs 0.096±0.023 min-1, P = 0.0288).
CONCLUSIONS:
A decrease in the Ktrans at the primary site was found in advanced N stage cases, which might indicate that the hypoxic status cause a high possibility of the metastasis. Advances in knowledge: A decrease in the Ktrans at the primary site suggested the high possibility of an advanced N stage..
5. Erina Kitamoto, Toru Chikui, Shintaro Kawano, Masahiro Ohga, Kouji Kobayashi, Yoshio Matsuo, Takashi Yoshiura, Makoto Obara, Hiroshi Honda, Kazunori Yoshiura, The application of dynamic contrast-enhanced MRI and diffusion-weighted MRI in patients with maxillofacial tumors., Academic Radiology, org/10.1016/j.acra.2014.08.016, 22, 2, 210-216, 2015.02, To elucidate the characteristics of four types of tumors, including squamous cell carcinoma (SCC), malignant lymphoma (ML), malignant salivary gland tumors (MSGTs), and pleomorphic adenoma (Pleo), in the maxillofacial region using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted MRI (DW-MRI)data.
MATERIALS AND METHODS:
A total of 59 tumors were included in this research. DCE-MRI and DW-MRI were performed. We applied the Tofts and Kermode model (TK model) for the DCE-MRI data and obtained three dependent parameters: the influx forward volume transfer constant into the extravascular extracellular space from the plasma (K(trans)), the fractional volume of extravascular extracellular space per unit volume of tissue (ve), and the fractional volume of plasma (vp).
RESULTS:
Among the K(trans) values, there were no significant differences between the three types of malignant tumors; however, there was a significant difference between the SCC and Pleo (P = .0099). The ve values of the Pleo were highest, with significant differences compared to the other categories (SCC, P = .0012; ML, P = .0017; and MSGT, P = .041). The ML had the lowest ve values, and there were significant differences between ML and the other two types of malignant tumors (SCC, P = .0278 and MSGT, P = .0062). In 14 (24%) cases, apparent diffusion coefficient (ADC) could not be measured because of poor image quality. The ADC values of the ML were lowest, whereas those of Pleo were highest, similar to that observed for ve.
CONCLUSIONS:
The Pleo tumors had lower K(trans) values and higher ve values, which are useful for differentiating them from the malignant tumors. Moreover, the ve was also useful for establishing a diagnosis of ML..
6. Chikui T, Obara M, Simonetti AW, Ohga M, Koga S, Kawano S, Matsuo Y, Kamintani T, Shiraishi T, Kitamoto E, Nakamura K, Yoshiura K., The principal of dynamic contrast enhanced MRI, the method of pharmacokinetic analysis, and its application in the head and neck region., Int J Dent, doi: 10.1155/2012/480659, 2012.11, The principal of dynamic contrast enhanced MRI, the method of pharmacokinetic analysis, and its application in the head and neck region..
7. Chikui T, Kitamoto E, Kawano S, Sugiura T, Obara M, Simonetti AW, Hatakenaka M, Matsuo Y, Koga S, Ohga M, Nakamura K, Yoshiura K, Pharmacokinetic analysis based on dynamic contrast-enhanced MRI for evaluating tumor response to preoperative therapy for oral cancer., J Magn Reson Imaging, doi: 10.1002/jmri.23704, 2012.06, 口腔扁平上皮ガンにおける、術前科学放射線の治療効果判定を、MRIのダイナミック撮影をコンパートメントモデル解析を用いる事により評価可能であるか検討した。治療高価判定としては、組織学的効果を大星、下里分類を用い、 gold standardとした。コンパートメントモデル解析から得られる、血管外細胞外のスペースveの変化量が、組織学的効果判定と相関する事を明らかにした。すなわわち、腫瘍細胞の減少による血管外細胞外スペースの割合の増加をMRでとらえる事が可能であることを示した。.
8. Matsubara R, Kawano S, Chikui T, Kiyosue T, Goto Y, Hirano M, Jinno T, Nagata T, Oobu K, Abe K, Nakamura S., Clinical Significance of Combined Assessment of the Maximum Standardized Uptake Value of F-18 FDG PET with Nodal Size in the Diagnosis of Cervical Lymph Node Metastasis of Oral Squamous Cell Carcinoma.
, Acad Radiol, 19, 6, 708-17, 2012.06.
9. Chikui T, Kawano S, Kawazu T, Hatakenaka M, Koga S, Ohga M, Matsuo Y, Sunami S, Sugiura T, Shioyama Y, Obara M, Yoshiura K., Prediction and monitoring of the response to chemoradiotherapy in oral squamous cell carcinomas using a pharmacokinetic analysis based on the dynamic contrast-enhanced MR imaging findings., Eur Radiol, DOI: 10.1007/s00330-011-2102-x, 2011 Aug;21(8), 2011.08.
10. Shiraishi T, Chikui T, Yoshiura K, Yuasa K., Evaluation of T2 values and apparent diffusion coefficient of the masseter muscle by clenching., Dentomaxillofac Radiol. , 40, (1), 35-41., 2011.01.
11. Chikui T, Shiraishi T, Tokumori K, Inatomi D, Hatakenaka M, Yuasa K, Yoshiura K., Assessment of the sequential change of the masseter muscle by clenching: a quantitative analysis of T1, T2, and the signal intensity of the balanced steady-state free precession., Acta Radiol. , 51, 6, 669-78., 2010.07.
12. TORU CHIKUI, TOMOKO SHIRAISHI, TAKAHIRO ICHIHARA, TOSHIYUKI KAWAZU, MASAMITSU HATAKENAKA, YUKIKO KAMI, KENJI YUASA , KAZUNORI YOSHIURA, Effect of clenching on T2 and diffusion parameters of the masseter muscle, Acta Radiologica, 51, 1, 58-63, 2010.01.
13. Toru Chikui, Mayumi Shimizu, Toshiyuki Kawazu, Kazutoshi Okamura, Tomoko Shiraishi, Kazunori Yoshiura, A quantitative analysis of sonographic images of the salivary gland: A comparison between the sonographic findings and the sialographic findings, UltrasoundinMed.&Biol., 35(8):1257-1264, 2009.08.
14. Toru Chikui, Kenji Tokumori, Ryosuke Zeze, Tomoko Shiraishi, Takahiro Ichihara, Masamitsu Hatakenaka, Kazunori Yoshiura, A fast Look-Locker method for T1 mapping of the head and neck region., Oral Radiol, 25:22–29, 2009.06.
15. 筑井徹、瀬々良介、市原隆洋、湯浅賢治、吉浦一紀, 2D-Look-Locker sequence を使用したT1計測の試み, 歯科放射線学会雑誌, 47(2):65-74, 2007.06.
16. TORU CHIKUI, KAZUTOSHI OKAMURA, KENJI TOKUMORI, SEIJI NAKAMURA, Quantitative Analyses of Sonographic images of the parotid gland in patient with Sjogren's syndrome., Ultrasound in Med. & Biol., Vol. 32, No. 5, pp. 617- 622, 2006, 2006.05.
17. Toru Chikui, Kenji Yuasa1, kenji Tokumori, Shigenobu Kanda, Naonobu Kunitake, Katsumasa Nakamura,, Change of sonographic findings on cervical lymph nodes before and after preoperative radiotherapy, European Radiology, 10.1007/s00330-003-2173-4, 14, 7, 1255-1262, (2004) 14:1255–1262, 2004.07.
18. 筑井徹,湯浅賢治,神田重信,中村和正,長田哲次,平木昭光, 術前放射線治療による頸部リンパ節の超音波所見の変化について, 頭頸部腫瘍, Vol.28,pp.211-217, 2002.03.
19. Chikui T., Yonetsu K., Nakamura T., Multivariate feature analysis of sonographic findings of metastatic cervical lymph nodes: contribution of blood flow features revealed by power Doppler sonography for predicting metastasis, AJNR Am J Neuroradiol., Vol.21,No.3,pp.561-567, 2000.05.
主要総説, 論評, 解説, 書評, 報告書等
1. 筑井 徹, 大賀 正浩, 北本 江梨奈, 白石 朋子, 川野 真太郎, 吉浦 敬, 吉浦 一紀, Quantification of Diffusion and Permeability of MRI in the Head and Neck Region, Journal of Radilogy and Radiation Therapy, 2014.03, Diffusion Weighted Image (DWI) has various roles such as tissue characterization, the prediction and monitoring of the response to treatment and
differentiation of recurrent tumors from post-therapeutic changes. The malignant tumors have a lower ADC compared to benign lesions. Follow-up of early response to cancer treatment is reflected in an ADC increase in the primary tumor and nodal metastases; whereas nonresponding lesions tend to reveal only
a slight increase or even a decrease in ADC during follow-up. However, there are many limitations regarding the performance of DWI in the head and neck
region, therefore, many attempts has been performed to overcome the flaws of the diffusion-weighted single-shot-echo planar imaging.
The pharmacokinetic analyses of dynamic contrast enhanced MRI (DCE-MRI) can provide physiological condition of the tissue, and Tofts and Kermode
Model has been applied to the head and neck region. Some researchers have used it for the prediction and monitoring of the tumor response to cancer therapy.
The general consensus is that the early changes of these parameters during the early phase after the treatment are useful for the interpretation of the response
to the treatment. However, the parameters reported in the literature vary considerably; therefore, it is difficult to compare the values of the parameters among research groups.
Both DWI and the pharmacokinetic analysis of the DCE-MRI have shown a wide range of potential benefits in this region, but more comparative studies with established scan techniques and the quantification of the data are required.
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2. 筑井 徹, Perfusionに関するパラメーター(DCE-MRI), メディカルビュー, 2013.09, MRIの技術の解説書 そのうち、Perfusionに関するパラメーター(DCE-MRI)に関する解説を行った。MRIのdynamic studyから薬物動態解析を行い、血漿から細胞外腔への移行、血管細胞外腔の割合などのパラメーターの算出法の解析を行った。.
3. Chikui T, Obara M, Simonetti AW, Ohga M, Koga S, Kawano S, Matsuo Y, Kamintani T, Shiraishi T, Kitamoto E, Nakamura K, Yoshiura K., The Principal of Dynamic Contrast EnhancedMRI, theMethod of Pharmacokinetic Analysis, and Its Application in the Head and Neck Region., Int J Dent, 2012.11, Many researchers have established the utility of the dynamic contrast enhanced-magnetic resonance imaging (DCE-MRI) in the differential diagnosis in the head and neck region, especially in the salivary gland tumors. The subjective assessment of the pattern of the time-intensity curve (TIC) or the simple quantification of the TIC, such as the time to peak enhancement (T(peak)) and the wash-out ratio (WR), is commonly used. Although the semiquantitative evaluations described above have been widely applied, they do not provide information on the underlying pharmacokinetic analysis in tissue. The quantification of DCE-MRI is preferable; therefore, many compartment model analyses have been proposed. The Toft and Kermode (TK) model is one of the most popular compartment models, which provide information about the influx forward volume transfer constant from plasma into the extravascular-extracellular space (EES) and the fractional volume of EES per unit volume of tissue is used in many clinical studies. This paper will introduce the method of pharmacokinetic analysis and also describe the clinical application of this technique in the head and neck region..
主要学会発表等
1. 筑井 徹1, 徳森 謙二, Panyarak Wannakamon, 山下 泰生,神谷武志, 栂尾 理, 吉浦 一紀 , 顎顔面部腫瘍の拡散強調画像に対するガンマ分布モデル法および簡易IVIM法の応用
, 第47回日本磁気共鳴医学会大会, 2019.09, 本文
【目的】ガンマ分布モデル(GD model)法および簡易IVIM法を顔面部腫瘍の拡散強調画像に応用し有用性を検討する事。

【方法】
対象は、Philips社製1.5T装置にてEPI型拡散強調画像 b値(0,500,1000,1500s/mm2)を撮像された症例。悪性76例(悪性リンパ腫:14, 扁平上皮癌:54, 悪性唾液腺腫瘍:7, その他:1)、良性27例(多形腺腫:6, 脈管系腫瘍:14, その他:7)である。gamma distribution (GD) model法では、shape parameter(κ)およびscale parameter(θ)を算出し、拡散係数をD<1.0x10-3mm2/s (f1), 1.0x10-3mm2/s3.0 x10-3mm2/s (f3)と区分し、細胞内拡散・細胞外拡散・灌流成分を反映すると想定した。簡易IVIM法では、 b値 0,500,1000 s/mm2より、D (true diffusion coefficient), f (perfusion fraction)を算出し、GD model法のパラメーターとの相関を検討した。
【結果】
悪性腫瘍は、良性腫瘍に比較し、有意に小さなκを持ち、f1は有意に大きく、 f2は、有意に小さかった。f1は、悪性リンパ腫, 扁平上皮癌, 悪性唾液腺腫瘍, 多形腺腫、脈管系腫瘍の順に減少し、特徴的であった。f3は、MLが小さく、脈管系腫瘍で大きかった。GD model法で得られたf1は、簡易IVIM法で得られたDと強い負の相関を認め、f3とfには強い正の相関を認めた。
【結論】
GD model法は、良悪性鑑別に有用であり、パラメーターは各病変の特徴を反映すると考えられた。またGD model法の結果は、簡易IVIM法の結果と比較しても妥当であると考えられた。
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2. Wannakamon Panyarak, Toru Chikui, Yasuo Yamashita, Kazunori Yoshiura, Image quality and ADC assessment in turbo-spin echo and echo-planar diffusion-weighted MR imaging of oral and maxillofacial tumors, 日本歯科放射線学会第59回学術大会, 2018.05, Purposes
The first was to compare the distortion ratio (DR) and the signal-to-noise ratio (SNR) between TSE-DWI and EPI-DWI. The second was to demonstrate the image distortion between TSE-DWI and T2 WI and to estimate ADC in various kinds of diseases.

Materials & Methods
At first, 42 patients underwent MRI using TSE-DWI and EPI-DWI. The DR, SNR, and ADC were compared between the two techniques.
Secondly, 160 underwent MRI using TSE-DWI. The distortion along X- and Y-axes was defined the distance from the centroids of the lesion on DWIb1000 to that of T2WI. We also estimated ADC values of the lesions.

Results
DR of TSE-DWI was significantly less than that of EPI-DWI and SNR of TSE-DWI was significantly higher than that of EPI-DW. ADC values of palatine tonsils and submandibular glands in TSE-DWI were significantly higher than those in EPI-DW.
The deviations along X-axis were 0.57±1.30 mm and that along the Y-axis were 0.27±1.74 mm, therefore, the image distortion was very small. Regarding the ADC values, cysts presented the highest values followed by vascular lesion and benign tumors, while malignant lymphoma showed the lowest values.

Conclusions
TSE DWI can produce less distortion and higher SNR than TSE-DWI, while TSE-DWI possibly exhibits different ADC values. Therefore, the TSE-DWI could be good alternative to EPI-DWI and is useful for the differential diagnosis..
3. Wannakamon Panyarak, Toru Chikui, Yasuo Yamashita, Kazunori Yoshiura, Image quality assessment in turbo-spin echo diffusion-weighted MR imaging and the correlation between the ADC value and the histological features of head and neck tumors, ASHNR 2017, 2017.09, Purpose
Many studies have supported the utility of diffusion-weighted images (DWIs) in the differential diagnosis. However, Echo-planar imaging (EPI) DWIs are susceptible to inhomogeneity of the magnetic field, which limits their usefulness in the head and neck region. Thus, the first purpose of this study was to evaluate the image distortion of Turbo-spin echo (TSE)-DWIs in comparison to anatomical images. The second purpose was to demonstrate the apparent diffusion coefficient (ADC) values in various types of head and neck lesions.

Materials & Methods
In all cases, MRI was performed using a clinical 3T whole-body MRI system (Philips Healthcare, Best, Netherlands). A total of 99 cases were enrolled. In each case, MRI was performed and T2-weighted images (T2WIs) and TSE-DWIs (b-value, 0 and 1000 s/mm2 [DWIb0 and DWIb1000]) were obtained.
At first, the DWI was reoriented onto a T2WI to match the matrix size and slice thickness. Then, we carefully drew the lesion, the bilateral Masseter muscles (MMs) and the spinal cord and defined them as regions of interest (ROIs) on a DWIb0, a DWIb1000 and a T2WI. The centroids of the ROIs were obtained. The differences along the X-axis (the direction of frequency encoding) and the Y-axis (the direction of phase encoding) were measured among these centroids. For the second purpose, an ADC map was obtained using DWIb0 and DWIb1000 images. All of the procedures were performed using the OsiriX Lite software program (Pixmeo SARL, Bernex, Switzerland) and the Image J software program (NIH, Maryland, USA).

Results
The 88 cases (89%) (benign tumor, n=20; malignant tumor, n=52; inflammation, n=9; cyst, n=7) could be evaluated by TSE-DWI .Eleven cases were excluded because their lesions were too small (n=8), or due to the presence of a severe metal artifact (n=3).
Focusing on the comparison of DWIb1000 images to T2WIs, the deviations along X-axis were 0.87±0.62 mm, 0.74±0.61 mm, and 0.42±0.38 mm (lesion, MMs, and spinal cord, respectively). Meanwhile, the deviations along the Y-axis were 1.37±1.28 mm, 1.44±0.99 mm, and 0.67±0.57 mm (lesion, MMs, and spinal cord, respectively). The deviation along the Y-axis was significantly larger than that along the X-axis in MMs and the spinal cord (p-value < 0.05); however, the absolute amount was not so large. In addition, the deviation that was observed between DWIb0 images and T2WIs was almost identical to that observed between DWIb1000 and T2WI (mean difference, <0.1 mm). Thus, the image distortion in the direction was not so severe.
Regarding the ADC values, cysts presented the highest values (1.91±0.59 x10-3 mm2/s) followed by benign tumors (1.46±0.44 x10-3 mm2/s), while malignant lymphoma showed the lowest values (0.86±0.12 x10-3 mm2/s). Thus, the ADC values obtained from TSE-DWIs were useful for evaluating these lesions.

Conclusions
TSE-DWIs were found to be immune to image distortion; thus, these images could be easily superimposed on anatomical images. Moreover, the ADC values that were obtained showed high diagnostic power in assessment of head and neck lesions.
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4. Toru Chikui, Wannakamon Panyarak, Yasuo Yamashita, Toshiyuki Kawazu, Kazunori Yoshiura, The detection of recurrence of oral cancer using turbo spin echo-diffusion-weighted imaging , ASHNR 2017, 2017.09, Objective
Many studies have supported the utility of diffusion-weighted image (DWI) for detecting recurrence. However, Echo-planar imaging DWIs are susceptible to inhomogeneity of the magnetic field, which limits its usefulness in the head and neck region. The first objective was to evaluate the utility of turbo spin echo (TSE)-DWI for detecting recurrence of oral cancer. The second objective was to compare the observer performance between TSE-DWI and gadolinium-enhanced T1-weighted imaging (Gd-T1WI).
Materials and Methods
Forty-two patients underwent surgery for oral squamous cell carcinoma and postoperative MRI, including axial T2-weighted imaging (T2WI), TSE-DWI and Gd-T1WI. All MRI procedures were performed using a 3T MRI system (Philips Healthcare, Best, the Netherlands). Twenty-two patients were classified as the recurrence group, and 20 were classified as the non-recurrence group. First, the DWI images were automatically adjusted for the translational and rotational motion to achieve superimposition with the Gd-T1WI images. We then assumed the high-signal-intensity area on DWIb1000 images or the enhanced area on Gd-T1WI images to indicate signs of recurrence and calculated the sensitivity and specificity. Once the enhanced area was identified, we outlined this area as a region of interest, copied it onto the adjusted ADC map, and measured the ADC value. These procedures were performed using the PACS system (Volume Analyzer Synapse Vincent; FUJIFILM, Tokyo, Japan). Next, two observers (observer 1: 22 years experience, observer 2: 3 years experience) interpreted the presence of recurrence using a five-point scale. The first session included the T1WI, T2WI and Gd-T1WI images, and the second included the axial T1WI, T2WI, DWIb1000, ADC map and combined T2WI and DWIb1000 fusion images. We estimated the area under the curve (AUC) using a receiver operating characteristic analysis. The image interpretation was performed on a personal computer using the OsiriX Lite software (Pixmeo SARL, Bernex, Switzerland).
Results
The sensitivity was 81.8% on both DWI b1000 and Gd-T1WI, and the specificity was 75% on DWI b1000 and 55% on Gd-T1WI. Although the specificity of DWI b1000 was quite high, the T2 shine-through might have reduced it to some degree. Of the 27 cases with enhanced areas on Gd-T1WI, the ADC of non-recurrence (1.82±0.51×10−3 mm2/s) was significantly higher than that of recurrence (1.14±0.113×10−3 mm2/s) (P<0.0001, Wilcoxon’s test). The AUCs in the first session including Gd-T1WI were 0.74±0.08 and 0.66±0.08 for observers 1 and 2, respectively. The AUCs in the second session including DWI were 0.79±0.07 and 0.82±0.06 for observers 1 and 2, respectively. There was a significant difference in the findings of observer 2 between the two methods (P=0.02). Therefore, DWI yielded a higher AUC, even if they did not used the enhanced MR images. In addition, a low ADC value was found to be characteristic of recurrence, and a good fusion image on DWI along with anatomical images were believed to help observers interpret the imaging findings.
Conclusions
TSE-DWI was found to be immune to image distortion and proved useful for differentiating between recurrence and a postoperative state. Adding the TSE-DWI sequence improved the observer performance regarding the interpretation of recurrence.
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5. Toru Chikui, Wannakamon Panyarak, 河津 俊幸, 山下 泰生, 武村 濃, 吉浦 一紀, 口腔扁平上皮癌術後の再発検出に対するTSE DWIの有用性, NPO法人 日本歯科放射線学会 第58回学術大会・第14回定例総会, 2017.06.
6. Tomoko Shiraishi, Toru Chikui, Kunihiro Miwa, Toyohiro Kagawa, Shoko Yoshida, Kenji Yuasa, Quantitative shear wave elastography for the differentiation between metastatic and inflammatory cervical lymph nodes., 11th Asian congress of oral and maxillo-facial Radiology, 2016.11.
7. Yoshitaka Kise, Toru Chikui, Yasuo Yamashita, Kouji Kobayashi, 吉浦 一紀, Eiichirou Ariji, Quantitative shear wave elastography for the differentiation between metastatic and inflammatory cervical lymph nodes., 11th Asian congress of oral and maxillo-facial Radiology, 2016.11.
8. Chikui T, Yamashita Y, Shimizu M, Yoshimura K, Estimation of the proton density fat fraction of the salivary gland, ASHNR 50th Annual Meeting, 2016.09, Purpose
The first purpose was to assess the value of a six-echo variant of the modified Dixon Quant (mDixon) for salivary gland fat fraction (FF) quantification against multi-echo T2 corrected MR spectroscopy which was used as the reference standard. The second goal was to apply mDixon to estimate the FFs and to compare them among the control group, Sjogren's syndrome (SS) group and IgG4 related disease (IgG4-RD) group.
Materials and Methods
To conduct this study, 10 healthy volunteers were enrolled and 20 parotid glands (PGs) were evaluated. Quantitative MRI was performed using the mDixon sequence in addition to single-voxel MRS to compare the mDixon-FF with MRS-FF. On the FF image obtained by the mDixon method, we measured the FF of the region of interest (ROI). For the MRS, five unsuppressed 1H spectra were acquired by the Stimulated Echo Acquisition Mode with different echo delays (TE=13-53ms). Time-domain quantification was performed using the AMARES algorithm from the MRUI software package. Relaxation times T2 of water and the four main different triacylglycerol components (5.3, 2.1,1.3,and 0.9 ppm) were determined. For the second purpose, we applied the mDixon sequence to 64 cases. Eleven patients were thus assigned to the SS group, 4 patients to the IgG4-RD group, and the remaining 49 patients to the control group with any abnormality of the salivary gland. The outlines of both the PGs and submandibular glands (SMGs) were traced to set the ROIs to estimate the FF. In the control group, we evaluated any correlations among the FF, height, weight, body mass index (BMI), cholesterol level, and serum triglyceride level. We also compared the FF among the three groups.
Results
The FF(mDixon) correlated closely with the FF(MRS) according to the following equation FF(mDixon)=1.06xFF(MRS)-2.6 with R2 of 0.99. Therefore, the FF(mDixon) was considered to be potentially appropriate for clinical use. The PG-FF of the control group positively correlated with the weight and BMI (?=0.32, P=0.024 and ?=0.59, P < 0.001, respectively). The SMG-FF also correlated with the weight, BMI and serum triglyceride levels (?=0.59,P=0.0228, ?=0.38,P=0.0067 and ?=0.52, 0.0004, respectively). The SS group had a higher PG-FF(50.3±1.7%) than both the control group (34.9±11.1%) and IgG4-RD group (35.2±21.7%) and a significant difference was found between the SS group and control group (P=0.0113, Steel-Dwass test). This trend was remarkable in the submandibular gland. The SS group had a significantly higher SMG-FF(41.1±25.9%) than both the control group (7.4±4.5%) and IgG4-RD group (3.9±3.2%) (P < 0.0001 and P=0.0258, respectively, Steel-Dwass test). Therefore, the SMG-FF was lower than the PG-FF in the control group (P < 0.001, paired t test), however fat may accumulate rapidly in SMG patients due to the progression of SS.
Conclusions
Estimating the FF of the salivary gland using mDixon was thus found to be highly accurate in comparison to the MRS method. Therefore, this modality is considered to be potentially appropriate for clinical application. The FF obtained by mDixon quantitatively revealed the characteristic fat accumulation (especially SMGs) in the SS group..
9. 筑井 徹, 山下 泰生, 武村 濃, 吉浦 一紀, 唾液腺内脂肪含有率の測定:MR spectroscopy (STEAM)とmDIXON Quantとの比較, 日本歯科放射線学会第57回学術大会, 2016.06, 健常ボランティアの耳下腺の脂肪含有率 (FF)を、MR spectroscopy(MRS)を用いて算出しmDIXON Quantを用いてFFを測定し、両者を比較した。 MRSでは、0.9, 1.3, 2.1, 5,2 ppmの4つのpeakが全対象において同定可能であった。1.3ppm peak (methylene基)が最大であり、全脂肪peakの60%をしめ、肝臓で報告されている値とほぼ同じ値であった。MRSから得られたFFとmDIXON QuantのFFは高い相関を認めた。.
10. 筑井 徹, 木瀬 祥貴, 山下 泰生, 小林 幸次, 武村 濃, 吉浦 一紀, mDIXON Quantによる唾液腺脂肪含有率の検討, 第43回日本磁気共鳴医学会大会, 2015.09, 目的 
第一にmDIXON Quantを用い、正常群の耳下腺および顎下腺の脂肪含有率 (FF)およびT2*を求め、年齢,身長,体重, BMI,血清コレステロール,中性脂肪との相関を検討する事。第二に正常群とシェーグレン症候群(SJS)群においてFF, T2*を比較する事。
方法 
対象は、唾液腺に病変のない正常群43名、SJS症例11名。撮像法は、6 point Dixon法であるmDIXON Quantを用いた。両側耳下腺、顎下腺に関心領域(ROI)を設定し、FFおよびT2*を算出した。統計はピアソンの相関係数、Wilcoxonの検定を用いた。
結果
1. 正常群において、耳下腺FFは、顎下腺FFに比較し有意に大きかった。BMIは、耳下腺・顎下腺FFともに有意に正の相関を認めた。中性脂肪は、顎下腺FFと正の相関を認めた。
2. SJS群の顎下腺FFは、正常群に比較し有意に大きかった(P=0.0003)。正常群の顎下腺FFは低いが、SJS症例では急速に全体的に脂肪沈着が進むためと考えられた。耳下腺では、SJS群が大きい傾向であったが有意差は認めなかった(P=0.070)。しかし、FFの標準偏差は、SJS群が正常群より有意に大きかった(P=0.0002)。耳下腺のFFは、正常群でもBMIの影響を受けるため、平均値では有意差を認めないが、腺破壊・脂肪沈着が局在的に進むため、標準偏差には有意差が生じたと考えられた。
まとめ 
顎下腺FFは、耳下腺FFより低いものの、いずれもBMIの影響が大きい事が明らかになった。SJS群と正常群との判別には、顎下腺ではFFの平均値、耳下腺ではFFの標準偏差が有効である事が示唆された。
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11. Yoshitaka Kise, Toru Chikui, Yashio Yamashita, Koji Kobayashi, Atsushi Takemura, Kazunori Yoshiura, Eiichiro Ariji, Salivary gland fat fraction estimated with a new MRI method, IADR, Objectives: Measurement of fat fraction (FF) in the salivary glands is important in such diseases as Sjogren'ssyndrome, and it can be performed with MR spectroscopy. However, there is a limit in clinical application due to the complicated manipulations. A new magnetic resonance imaging (MRI) method, named mDIXON Quant, is convenientfor clinical application. The aim of this study was to estimate FF in the salivary glands using two different methods,mDIXON Quant and MR spectroscopy, and then to investigate the clinical usefulness of mDIXON Quant incomparison with MR spectroscopy.Methods: Sixteen healthy volunteers were enrolled in this study. They received two types of MRI examination,mDIXON Quant (6-point DIXON method) and MR spectroscopy (PRESS Single TE method), to measure FF in theparotid and submandibular glands. Ten subjects were also scanned by PRESS Multi TE method to determine theeffect of T2 value. On mDIXON Quant images, the regions of interest were set on both sides of the parotid andsubmandibular glands using the obtained FF map to determine FF.Results: 1. High correlation was observed in FF measured by mDIXON Quant and PRESS (Single TE) (slope=1.07, R2=0.960). 2. T2 value of the fat peak calculated by PRESS (Multi TE) was greater than T2 value of the water peak. 3. Even in taking the effect of T2 value by Multi TE method into account, a high correlation between mDIXON Quantand PRESS (Multi TE) was observed (slope=0.594, R2=0.964).Conclusions: The mDIXON Quant method appeared to be effective for FF measurement in the salivary glandsbecause the values obtained by mDIXON Quant correlated well with those by MR spectroscopy..
12. 木瀬 祥貴, 筑井 徹, 山下 泰生, 小林 幸次, 武村 濃, 吉浦 一紀, 唾液腺内脂肪含有率の測定:DIXON QuantおよびMR spectroscopyとの比較
, 日本歯科放射線学会第56回学術大会, 2015.06, 目的
健常ボランティアの耳下腺および顎下腺の脂肪含有率 (FF)をmDIXON QuantおよびMR spectroscopy (MRS)の2種類の方法で測定し、両者の相関を求めの強さ、mDIXON Quantがの臨床に使用できるか否か的有用性についてを検討する事。

方法
対象は、健常ボランティア15名を対象とした。使用した装置は、フィリップス社製 Ingenia 3.0Tである。6point Dixon法であるmDIXON QuantとMRSとしてPRESS法(Single TE)での撮像を行った。10名については、T2時間の影響を考慮する為 PRESS (Multi TE)での撮像も行った。mDIXON Quantでは、得られたFF mapより両側耳下腺、顎下腺に関心領域を設定し、FFを求めた。

結果
1. mDIXON QuantとPRESS Single TEにて測定したFFに関して、両者に非常に高い相関が認められた(slope=1.05 R2=0.957)。
2. PRESS (Multi TE)によるり脂肪peakのT2値は、水peakのT2値より大きかった。
3. Multi TE法によりT2時間の影響を考慮した場合においても、mDIXON QuantとPRESSで求めたFFとの間に高い相関を認めた(slope=0.61 R2=0.975)。

まとめ
mDIXON Quantで求めた耳下腺・顎下腺のFFは、PRESSで求めたFFと非常に高い相関を示し、臨床的有用性が高いと思われた.
13. 筑井 徹, 木瀬 祥貴, 山下 泰生, 小林 幸次, 武村 濃, 吉浦 一紀, mDIXON Quantによる唾液腺脂肪含有率の検討

, 日本歯科放射線学会第56回学術大会, 2015.06, mDIXON Quantによる唾液腺脂肪含有率の検討

筑井徹1、木瀬祥貴1、山下 泰生2、小林 幸次2、武村 濃3、吉浦 一紀1
1. 九州大学大学院歯学研究院口腔画像情報科学分野
2. 九州大学病院医療技術部放射線部門
3. フィリップスエレクトロニクスジャパン

目的
第一に健常者の耳下腺および顎下腺の脂肪含有率 (FF)を求め、身長,体重, BMI, 血清コレステロール, 中性脂肪との相関を検討する事。第二に健常者群とシェーグレン症候群(SS)群においてFFを比較する事。

方法
対象は、健常者35名、SS症例8名。使用した装置は、フィリップス社製 Ingenia 3.0Tである。撮像法は、6point Dixon法であるmDIXON Quantを用いた。得られたFF mapより両側耳下腺、顎下腺に関心領域を設定し、耳下腺FF、顎下腺FFとした。

結果
1. 健常者の耳下腺のFFは、37±11%であり、体重,BM,中性脂肪の増加に従い増加する傾向にあったが、有為な相関は認めなかった。
2. 健常者の顎下腺のFFは、8.5±4.7%であり、体重, BMI,中性脂肪とは正の相関を認めた。
3. SS群のFFは、耳下腺においては、健常者に比較し大きな傾向にあったが、有意差は認めなかった。一方、SS群の顎下腺FFは、41±29%であり、健常者群8.5±4.7%に比較し、有意差を認めた(P=0.02, Wilcoxon/Kruskal-Wallis test)。

まとめ
 顎下腺のFFは、体重、BMIおよび中性脂肪値と正の相関を示すが、SS群のFFは、それらの生理的な変動に考慮しても、正常群より大きかった。顎下腺FFはSSの診断に有用である事が示唆された。
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14. 筑井 徹, 北本 江梨奈, 川野 真太郎, 吉浦 一紀, 口腔扁平上皮癌におけるDCE-MRIの薬物動態解析, 日本歯科放射線学会第56回学術大会, 2015.06, 目的
口腔扁平上皮癌症例において、薬物動態解析により得られたバラメーターと原発部位,分化度, TNM分類との相関を検討する事。

方法
対象は85名の扁平上皮癌患者。使用した装置は、フィリップス社製 Achieva 1.5T Nova Dual。DCE-MRIは、3D-T1FFEにて撮像し、3.5s毎,80相を撮像した。DataをTK model 解析し、原発巣のAUGC, Ktrans, ve, vpを算出した。T1 map作成はdual flip angle法を用い、動脈入力関数はmodel AIFを使用した。TNM分類には、視診触診,CT, MRI, USおよびPET-CTを用いた。

結果
1. いずれのパラメーターも原発部位, 分化度, T stageによる有意差は認めなかった。
2. N stageの進行した症例では、AUGCおよびKtransが減少する傾向がみられ、AUGCではN0群とN2+3群、KtransではN0群とN2+3群およびN1群とN2+3群に有意差を認めた。

考察およびまとめ
N stageの進行した症例では、AUGCおよびKtransが減少する傾向がみられ、血流減少による低酸素状態がリンパ節転移に関与する可能性が示唆された。

略語
AUGC: 造影剤濃度の積分値
Ktrans:造影剤の血漿から血管外細胞外腔への移行定数
ve :血管外細胞外腔の占める割合
vp :血漿の占める割合
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15. Kazutoshi Okamura, Yutaka Yoshida, Chikui Toru, Kazunori Yoshiura, Evaluation of improvement effect on the iterative reconstruction method in hard tissue, The 10th Asian Congress of Oral and Maxillo Facial Radiology, 2014.11, Institution and Country
Department of Oral & Maxillofacial Radiology, Faculty of Dental Science, Kyushu University, Japan.
*Department of Health Sciences, Faculty of Medical Sciences, Kyushu University, Japan.

Correspondence e-mail
okamura@rad.dent.kyushu-u.ac.jp

Introduction
Iterative Reconstruction (IR) algorithms for Computed Tomography (CT) is widely used in clinical practice in late years. Although improvement in image quality and dose reduction have been reported, many were evaluated based on soft tissue.

Objectives
To evaluate improvement effect on the IR method in hard tissue like teeth and bone, with high-contrast object.

Materials and methods
Images of a high-contrast and a water cylinder phantom were acquired with Alexion four-row CT (Toshiba Medical Systems, Tokyo, Japan) at 120 kV tube voltage and five tube current levels. They were reconstructed with filtered back projection (FBP) and adaptive iterative dose reduction three-dimensional (AIDR 3D; Toshiba Medical Systems) reconstruction algorithms using the bone kernel. The slice thickness was 1.0mm and the reconstruction FOV was 70.2mm. The minimum separable hole size was estimated on the images of the high contrast phantom and the noise power spectrum (NPS) was measured on the images of the water cylinder phantom for FBP and for four levels of AIDR 3D.


Results
The NPSs of AIDR 3D were lower than that of FBP. The noise reduction effect was observed visually at low tube current. The minimum separable hole size was 0.5mm at 150 and 100mA, it raised by lowering tube current, and it was 1.0mm at 10mA. There ware no effect of AIDR 3D in detection size.

Conclusions and discussion
On these conditions, the effect of AIDR 3D did not lead to improvement in detection ability. At the time of evaluation of the hard tissue with low tube current, use of AIDR 3D may have an opposite effect. Evaluation with complicated structures like trabecular bone is required.
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16. Tomoko Shiraishi, Chikui Toru, Marie Hashimoto, Kenji Yuasa, Evaluation of Malignant lymphoma(ML) using MRI and US, The 10th Asian Congress of Oral and Maxillo Facial Radiology, 2014.11, Introduction
Malignant lymphoma(ML)almost occurs in lymph node, but rare extranodal. It was frequently mistaken for another malignant tumor.
Objectives
To elucidate the characteristics of ML imaging features in head and neck region.
Materials and methods
We described 8 patients (5 male and 3 female, average age, 67 years, age range 20). 8 lesions were histopathologically diagnosed as ML (tongue, 1 buccal mucosa, 3 maxilla and palate, 3 submandibular, 1) between 2006 and 2012. MRI was performed all lesions. We evaluated the signal intensity (SI) of T1WI, T2WI and estimated the diffusion coefficient (ADC) with b-factors of 0,500,1000 sec/mm2. In four cased, the dynamic MRI study was performed and the time intensity curve (TIC) was obtained. US was performed 2 lesions. US end point was internal echogenicity, internal vascularity, posterior echo enhancement.
Results
All ML cases had low intensity on T1WI. On T2WI, SI ranged from middle to high intensity. Mean ADC values were 0.771±0.142 sec/mm2 for ML, which were significantly lower than squamous cell carcinoma (? ± ??sec/mm2 in our preliminary study). TIC type showed a rapid increase downward titration type or a rapid increase storm decrease type.
Conclusions and discussion 
On both T1WI and T2WI, SI was not specific for ML. However, ADC was extremely low and the most characteristic finding, which suggested the small amount of extracellular space.
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17. Chikui Toru, Erina Kitamoto, Masahiro Ohga, Kazunori Yoshiura, The pharmacokinetic analysis of the dynamic contrast –enhanced MRI in maxillofacial region., The 10th Asian Congress of Oral and Maxillo Facial Radiology, 2014.11, Introduction
Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is widely performed, but cannot elucidate the underlying physiological conditions. A pharmacokinetic analysis of the DCE-MRI findings may provide such information.
Objectives:
To elucidate the characteristics of tumors using a pharmacokinetic analysis.
Materials and Methods
A total of 135 tumors were examined[91 squamous cell carcinomas (SCC), 24 malignant lymphomas (ML), 10 malignant salivary gland tumors (MSGTs) and 10 pleomorphic adenomas (Pleo)]. We applied the Tofts and Kermode model and obtained three parameters: the influx forward volume transfer constant into the extravascular extracellular space (EES) from the plasma (Ktrans), the fractional volume of EES (ve) and the fractional volume of plasma (vp). We compared the parameters among the four types of tumors and also evaluated the correlation between the TMN stage and the parameters in SCC.
Results
ML had a significantly lower ve than the other categories (SCC; P<0.0001, MSGT; P=0.049 and Pleo; P=0.0001) and it also had the lowest Ktrans. Pleo had the highest ve value, significantly higher than that of SCC (P=0.0033), and had the lowest vp, which was significantly different from SCC (P=0.018). A small amount of EES and low permeability were characteristic of ML, while a large amount of EES and poor vascularity were characteristic of Pleo. In SCC, the Ktrans decreased with the progression of the N stage, and the Ktrans of N2 cases was lower to that of No cases (P = 0.0028).
Conclusions
The pharmacokinetic analysis clarified the physiological conditions of the tumors.
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18. 筑井 徹, 北本 江梨奈, 大賀 正浩, 小林 幸次, 吉浦 敬, 小原 真, 白石 朋子, 稲富 大介, phase 情報を用いた動脈入力関数(AIF) 算出の試み- 顎顔面領域への応用-, 第41回日本磁気共鳴医学会大会, 2013.09, 位相画像を用いたAIF算出を試み、コンパートメントモデル解析に与える影響を検討した。個人差を反映するAIF算出としてphase情報は、有用性が示唆されるものの、dynamic撮像中に蓄積するエラーにより、平衡相のAIFに変動をあたえ、血管外細胞外腔(ve)が不正確になるケースが見られた。.
19. 筑井 徹, 北本 江梨奈, 大賀 正浩, 小林 幸次, 吉浦 敬, 小原 真, DCE MRI, ADC mapを用いた耳下腺の急性期放射線障害の評価, 第41回日本磁気共鳴医学会大会, 2013.09, 放射線照射による急性期耳下腺障害をDCE-MRIの薬物動態解析, ADC mapおよび体積変化により評価した。mean doseが増えるとKtrans、ve、ADCは増加し、その変化は、比較的低線量でも確認された。 Ktransの増加は照射による血流増大、血管透過性の亢進を反映し、veの増加は腺細胞の消失によるEESの増大を反映していると考えられた。.
20. 北本江梨奈, 筑井 徹, 吉浦 一紀, phase Imageを用いた動脈入力関数(AIF)算出の試み, 日本歯科放射線学会第54回総会・学術大会, 2013.06.
21. 筑井 徹, 北本江梨奈, 吉浦 一紀, コンパートメントモデルを使用したDCE-MRI解析口腔扁平上皮癌症例の術前治療効果判定の試み, 日本歯科放射線学会第54回総会・学術大会, 2013.06.
22. Toru Chikui, Erina Kitamoto, Shoichi Koga, Arjan Simonetti, Makoto Obara, Takashi Yoshiura, Kazunori Yoshiura, The application of phase AIF for pharmacokinetic analyses in the maxillofacial region, 25th Congress and Refresher Course of the European Society of Head and Neck Radiology, 2012.09, OBJECTIVE
The individual arterial input function (AIF) is preferable for accurate pharmacokinetic analyses, even if the estimation of the individual AIF in the neck is challenging. The purpose of this study is to apply phase information when estimating the AIF for pharmacokinetic analysis.

Materials and methods
Thirteen patients underwent dynamic DCE-MRI. The scan included 3D-T1 FFE sequences with a temporal resolution of 3.5 s. Both magnitude and phase-shift images were reconstructed. the concentration of contrast medium (CM) in tissue (Ct (t)) was estimated using the magnitude image. The phase image was used to estimate the concentration of CM in artery (Ca (t)).
The average Δφwas converted to Ca(t) using the equation:
Δφ = TE ・ π ・γ ・B0 ・ χm ・ΔCa・ (cos2θ-1/3)
where γ is the proton gyromagnetic ratio, B0 is the magnitude of the main magnetic field in Tesla, χm is the molar susceptibility of the CM, and θ is the angle of the vessel relative to the main magnetic field.
The concentration of CM in plasma (Cp (t)) was defined as;
Cp (t) = Ca /(1-Hematocrit).
A single observer, aware of the primary tumor site, placed a ROI on the ipsilateral ICA for the estimation of the AIF. Next, the observer placed it on the contraleral ICA. The peak concentration (Ca peak), the average of the concentration (Ca avg), and the concentration during last 30 phases (Ca last 30) were compared between the ipsilateral and contraleral ICA.
Secondly, the pharmacokinetic analysis in TK model was applied to each voxel, where Ktrans is influx forward volume transfer constant, ve is fractional volume of EES and vp is the fractional volume of plasma. Quantitative measurements derived from the ipsilateral ICA reference curves were compared with similar measurements derived from a contralateral reference.
Results.
The AIF could be estimated on both sides in 11 out of 13 patients . The AIF could not be obtained in one patient due to severe body motion. The contralateral AIF was observed to fluctuate in another patient during the equilibrium phase.
 There was a high correlation between the ipsilateral ICA and the contraleral ICA in both the Capeak and Caavg (Ca peak, slope = 0.95,r = 0.79;and Ca avg, slope = 0.97, r = 0.65). The Ca last 30 had a somewhat lower correlation than either Ca peak or Ca avg. (Ca last30, slope = 0.97,r = 0.49), which may have been affected by the body motion and the lower SN ratio.
 None of the pharmacokinetic parameters were significantly different, whether the AIF ROI was on the ipsilateral ICA or the contralateral ICA. There was a high correlation in all parameters (Ktrans, slope = 0.94,r = 0.79; ve, slope = 0.96, r = 0.86; and vp, slope = 0.90, r = 0.70).

CONCLUSION.
Ktrans shows good absolute agreement (high correlation coefficient, slope≒1.0) between AIFipsi and AIFcontra. The phase images are thus found to be potentially useful for estimating the AIF and making Ktrans map in the maxillofacial region. However, there is a week agreement on Ve due to the inaccurate estimation of the AIF during late phases. Therefore, the population-averaged AIF might be preferable for the estimation of Ve.
.
23. Erina Kitamoto, Toru Chikui, Shintaro Kawano, Tsuyoshi Sugiura, Makoto Obara, Takashi Yoshiura, Kazunori Yoshiura., The application of a pharmacokinetic analysis to maxillofacial tumors, 25th Congress and Refresher Course of the European Society of Head and Neck Radiology, 2012.09, OBJECTIVES: This study was designed to elucidate the characteristics of a primary tumor in the maxillofacial region using pharmacokinetic
analyses based on the TK model.

MATERIALS AND METHODS: Dynamic contrast enhanced MRI (DCE-MRI) was performed for 54 patients (35 squamous cell carcinoma, 10 malignant lymphoma, 4 malignant gland tumor,5 pleomorphic adenoma). The axial DCE scan consisted of a 10 slice, 3D-T1 fast-field echo sequence. A T10 map was estimated by the dual flip angle method (5° and 15°) and the signal intensity of tissue was converted into the concentration of the contrast medium in tissue. The area under the gadolinium concentration curve (AUGC) was calculated after injection. The data were analyzed using a TK model. The influx forward volume transfer constant into EES from plasm (Ktrans), fractional volume of the extravascular extracellular space (ve), and fractional volume of the plasma (vp) were estimated. This study used a predefined model arterial input function. The MR image data (Philips PAR/REC format) were transferred to a personal computer from the MRI operating console and processed using a proprietary software program (PRIDE software, Philips Healthcare, Eindhoven, The Netherlands) using the RSI interface data language (IDL). Tukey' s HSD test was used to compare the parameters among the four categories.

RESULTS: ML had the lowest AUGC among the four categories and there was a significant difference between ML and SCC (P<0.05). The malignant tumors had a higher Ktrans than the pleomorphic adenoma, which might reflect the fact that the angiogenesis factors from the malignant tumor caused the higher permeability. .
24. 筑井徹、北本江梨奈、川野真太郎、古閑省一、大賀正浩、松尾芳雄、神谷武志、吉浦敬、小原真、吉浦一紀 , Diffusion MRI およびPermeability MRIによる口腔扁平上皮癌症例の術前治療効果判定の試み, 第40回日本磁気共鳴医学会大会, 2012.09, 目的
口腔扁平上皮癌患者の術前化学放射線治療前後においてADC値や、dynamic contrast MRI(DCE-MRI)の定量解析により得られる指標が、組織学的抗腫瘍効果判定を反映するか検討する。

方法
口腔扁平上皮癌患者で、術前治療前および術前治療後に拡散強調像およびDCE MRIを撮像した37症例を対象とした。術前治療は、外照射30GyおよびTS-1を基準とした。拡散強調画像では、b factorを0,500,1000, 1500s/mm2とし、ADCを算出した。DCE-MRIでは、3.5秒毎80フェーズを収得し、画像データを2コンパートメントモデル解析した(Philips社製 PRIDE)。術前治療の組織学的抗腫瘍効果は、手術後の摘出標本を対象に、大星・下里の分類を用いて判定した。解析では、Grade ⅠおよびⅡaをnon-responder群、Ⅱb、Ⅲ、Ⅳ群をresponder群とした。

結果
治療前後とも評価できたのは、コンパートメントモデル解析では、35/37症例であったが、ADCの評価は、21/37症例のみであった。
治療前のパラメータでは、いずれも両群間に有意差を認めなかった。治療後では、responder群のADC[(1.37±0.05)x10-3mm2/s]は、non-responder群[(1.17±0.07)x10-3mm2/s]より有意に大きかった(P=0.04)。コンパートメントモデル解析でえられる血管外細胞外腔の割合(ve)もresponder群(0.394±0.016)は、non-responder群(0.288±0.023)に比較し有意に大きかった(P=0.01)。

考察
responder群では、治療により癌胞巣の破壊による細胞間質の増加の割合が大きく、その事が、ADCの増加、veの増加に反映されたと考えられた。顎顔面領域では、拡散強調像のアーチファクトを考慮するとDCE-MRIのコンパートメントモデル解析が有利であると考えられた。
.
25. 北本江梨奈, 筑井徹, 吉浦一紀 , コンパートメントモデルを使用したDCE-MRI解析–顎顔面部の鑑別診断の試み, 第31回関西・九州合同地方会, 2011.12.
26. 筑井徹、北本江梨奈、吉浦一紀 , コンパートメントモデルを使用したDCE-MRI解析口腔扁平上皮癌症例の術前治療効果判定の試み, 第31回関西・九州合同地方会, 2011.12.
27. Toru Chikui, Shintaro Kawano, Syouzou Koga, Masahiro Ooga, Toshiyuki Kawazu, Erina Kitamoto , Kazunori Yoshiura, Evaluation of the effect of CRT for oral cancer using a Brix model of DCE-MRI, 18th International Congress of Dento-Maxillo-Facial Radiology, 2011.05.
28. Toshiyuki Kawazu, Toru Chikui, Tomoko Shiraishi, Masamitsu Hatakenaka and Kazunori Yoshiura, Evaluation of masseter muscle before and after contraction using Real-time tissue Elastography, 23rd ESHNR Annual Meeting, 2010.09.
29. 筑井徹, 畠中正光, 薮内英剛,古閑省一, 西川啓, 加美由紀子, 小原真, 口腔扁平上皮癌症例の術前治療効果判定 (TK modelによる薬物動態解析と組織学的抗腫瘍効果判定の相関), 第38回日本磁気共鳴医学会, 2010.09.
30. 筑井徹, 畠中正光, 薮内英剛,古閑省一, 西川啓, 加美由紀子, 小原真, 口腔扁平上皮癌症例の術前治療効果判定 (Brix modelによる薬物動態解析と組織学的抗腫瘍効果判定の相関), 第38回日本磁気共鳴医学会, 2010.09.
31. Toru Chikui, Shintaro Kawano, Yoshio Matsuo, Syunya Sunami, Takeshi Kamitani, Syozou Koga, Kazunori Yoshiura., Evaluating the effect of preoperative chemoradiotherapy using a pharmacokinetic analysis of dynamic contrast enhanced MR imaging (2), 23rd ESHNR Annual Meeting, 2010.09.
32. 筑井 徹, 咬合による咬筋のT1値、T2値、balanced SSFPの信号強度の変化の検討, 第29回 日本画像医学会, 2010.02.
33. Tomoko Shiraishi, Toru Chikui, Takahiro Ichihara, Toshiyuki Kawazu, Kazunori Yoshiura, Kenji Yuasa, T2values and ADC of Masseter muscle increase during clenching, 17 International congress of dentomaxillofacial radiology, 2009.07.
34. 筑井徹、白石朋子、市原隆洋、河津俊幸、湯浅賢治、吉浦一紀 , 咬合が咬筋におよぼすT2値および拡散テンソルの固有値の検討, 日本歯科放射線学会 第50回学術大会, 2009.05.
35. Toru Chikui, Mayumi Shimizu, Toshiyuki Kawazu, Kazutoshi Okamura,Kazunori Yoshiura, A quantitative analysis of sonographic images of the salivary gland: A comparison between the sonographic findings and the sialographic findings., 7th Asian congress of Oral and maxillofacial Radiology, 2008.11.
36. Tomoko Shiraishi, Toru Chikui, Takahiro Ichihara, Kazunori Yoshiura, Kenji Yuasa, Evaluation on changes of T2 values and ADCs of the Masseter muscle by Clenching. , 7th Asian congress of Oral and maxillofacial Radiology, 2008.11.
37. Toru Chikui, Kenji Tokumori, Ryousuke Zeze, Takahiro Ichihara, Kazunori Yoshiura, Attempt for estimating parameters in the orofacial region by dynamic contrast-enhanced T1-weighted MRI. , 7th Asian congress of Oral and maxillofacial Radiology, 2008.11.
38. 筑井徹、瀬々良介、市原隆洋、木原由香、湯浅賢治、吉浦一紀, 「頭頸部におけるGd造影剤濃度の算出の試み-ファントム実験および臨床症例への適応-」, 日本歯科放射線学会 題49回学術大会, 2008.05.
39. 筑井徹、清水真弓、河津俊幸、岡村和俊、吉浦一紀, 「唾液腺超音波像の定量化: 超音波所見と唾液腺造影像の比較」, 日本歯科放射線学会 題49回学術大会, 2008.05.
40. 筑井徹、瀬々良介、市原隆洋、木原由香、湯浅賢治、吉浦一紀, 「頭頸部におけるGd造影剤濃度の算出の試み-ファントム実験および臨床症例への適応-」, 日本歯科放射線学会 題49回学術大会, 2008.05.
41. 筑井徹、徳森謙二、 白石朋子 、瀬々良介、市原隆洋、湯浅賢治 、吉浦一紀, 2D-Look-Locker sequence を使用した頭頸部T1 mapping, 日本歯科放射線学会 第50回関西・第46回九州合同地方会, 2007.12.
42. 筑井徹、瀬々良介、市原隆洋、湯浅賢治、吉浦一紀, Look-Locker sequenceによるT1時間測定ーファントムによる検討および頭頸部への応用, 第43回九州・第49回関西合同地方会, 2006.11.
43. 筑井徹、岡村和俊、徳森謙二、清水真弓、吉浦一紀, 口腔乾燥症の超音波像の定量解析, 第42回九州・第48回関西合同地方会, 2005.12.
44. 筑井 徹, 口腔癌の診断において超音波が寄与する役割について, 日本歯科放射線学会総会, 2005.05.
45. 筑井 徹, 頸部リンパ節における診断の現状(特に超音波ドップラ法について), 第43回日本歯科放射線学会, 2002.10.
学会活動
所属学会名
日本磁気共鳴医学会
日本歯科放射線学会
日本画像医学会
日本超音波医学会
日本口腔科学会
日本口腔インプラント学会
国際顎顔面放射線学会
学協会役員等への就任
2012.04~2014.03, 日本歯科放射線学会, 代議員.
2008.07~2008.10, 日本歯科放射線学会, 認定委員会問題作成委員.
2008.04, 日本歯科放射線学会, 評議員.
2007.05, 日本歯科放射線学会, 医療情報委員会.
2006.08, 日本歯科放射線学会, ガイドライン策定委員.
学会大会・会議・シンポジウム等における役割
2019.11.22~2019.11.23, 第24回臨床画像大会, 座長.
2017.11.26~2017.11.26, 日本歯科放射線学会 教育研修会「第29回 実技研修会・超音波診断」, 教育講演演者.
2017.11.25~2017.11.25, 第 50 回 NPO 法人日本口腔科学会九州地方部会教育研修会, シンポジスト.
2017.11.25~2017.11.25, 第50回口腔科学会地方部会学術研修会, シンポジスト.
2017.07.29~2017.07.29, 第19回 日本口腔顎顔面外傷学会総会・学術大会, シポジスト.
2017.07.29~2017.07.29, 第19回日本口腔顎顔面外傷学会総会・学術大会, シンポジスト.
2017.06.03~2017.06.04, NPO法人 日本歯科放射線学会 第58回学術大会・第14回定例総会, 座長.
2017.06.03~2017.06.04, NPO法人 日本歯科放射線学会 第58回学術大会・第14回定例総会, 座長(Chairmanship).
2016.12.10~2016.12.10, NPO 法人 日本歯科放射線学会 第36回関西・九州合同地方会, 準備委員長.
2016.12.10~2016.12.10, NPO法人日本放射線学会第36回関西・九州合同地方会, 準備委員長.
2015.10.25~2015.10.25, 第28回生涯学習研修会(歯科エックス線優良医講習会), 実施責任者.
2012.12.08~2012.12.08, 日本歯科放射線学会第32回関西・九州合同地方会, 座長(Chairmanship).
2012.05.19~2012.05.20, 第72回九州歯科学会総会学術大会, シンポジスト.
2011.12.10~2011.12.10, 日本歯科放射線学会第31回関西・九州合同地方会, 座長(Chairmanship).
2011.05.25~2011.05.29, 18th International Congress of Dento-Maxillo-Facial Radiology, 座長(Chairmanship).
2010.12.11~2010.12.11, 日本歯科放射線学会 第49回九州地方会・第53回関西地方会, 座長(Chairmanship).
2009.10.24~2009.10.26, 日本歯科放射線学会 臨床画像大会, 座長(Chairmanship).
2008.05.16~2008.05.16, 日本歯科放射線学会 学術大会, 座長(Chairmanship).
2008.05~2008.05, 日本歯科放射線学会第49回学術大会, 座長.
2005.12~2005.12, 第42回九州・第48回関西合同地方会, 座長.
2005.12~2005.12, 日本歯科放射線学会 九州、関西合同地方会, 座長(Chairmanship).
2005.08~2005.08, 日本歯科放射線学会 九州地方会, 座長(Chairmanship).
2005.05~2005.05, 第45回 日本歯科放射線学会総会, シンポジスト.
2004.11~2004.11, 第40回九州・第47回関西合同地方会, 座長.
2004.11~2004.11, 日本歯科放射線学会 関西、九州合同地方会, 座長(Chairmanship).
2003.09~2003.09, 第44回 日本歯科放射線学会, ゲストスピーカー(学会賞受賞講演).
2003.05~2003.05, 第8回 臨床画像大会, 座長.
2002.10~2002.10, 第43回 日本歯科放射線学会総会, シンポジスト.
2002.05~2002.05, 日本歯科放射線学会 臨床画像大会 , 座長(Chairmanship).
学会誌・雑誌・著書の編集への参加状況
2012.05~2013.01, Internal journal of Dentistry. (Special issue on New Current and Advanced Diagnositic Imaging for Oral and Maxillofacial Disease.), 国際, 編集委員.
学術論文等の審査
年度 外国語雑誌査読論文数 日本語雑誌査読論文数 国際会議録査読論文数 国内会議録査読論文数 合計
2019年度      
2018年度      
2017年度      
2016年度
2015年度 12        12 
2014年度      
2013年度      
2012年度      
2011年度      
2010年度      
2009年度
2006年度
その他の研究活動
海外渡航状況, 海外での教育研究歴
チュラロンコーン大学, コンケーン大学, Thailand, Thailand, 2000.12~2000.12.
チェンマイ大学, Thailand, 2002.12~2002.12.
受賞
優秀発表賞, 日本矯正歯科学会, 2013.10.
Yoshida Award, NPO法人日本歯科放射線学会, 2008.11.
優秀論文賞, 日本歯科放射線学会, 2003.10.
研究資金
科学研究費補助金の採択状況(文部科学省、日本学術振興会)
2019年度~2021年度, 基盤研究(C), 分担, Compressed sensingを用いた頭頸部病変の高時間分解能血流動態評価.
2020年度~2018年度, 基盤研究(C), 代表, 統計学modelを用いた拡散情報と薬物動態解析の総合評価 頭頸部への応用.
2015年度~2017年度, 基盤研究(C), 代表, 顎顔面部における可動性蛋白質/ペプチドの化学交換イメージングの検討.
2012年度~2014年度, 基盤研究(C), 代表, MRIによる頭頸部病変のpermeabilityおよびperfusionの総合評価.
2009年度~2011年度, 基盤研究(C), 代表, HーMRI、PーMRSによる咬合の咀嚼筋に及ぼす影響の画像的評価.
2009年度~2011年度, 基盤研究(C), 分担, 歯科用コーンビームCT検査の最適化のための総合的CT性能評価法の開発.
2006年度~2008年度, 一般研究(C), 分担, 造影MRIを用いた頭頸部Kinetic Analysisの試み.

九大関連コンテンツ

pure2017年10月2日から、「九州大学研究者情報」を補完するデータベースとして、Elsevier社の「Pure」による研究業績の公開を開始しました。
 
 
九州大学知的財産本部「九州大学Seeds集」