||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.
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.
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..
||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.
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.
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).
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..
||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.
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.
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.
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..
||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.
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.
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).
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..
||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).
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.
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..
||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..
||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。.
||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.
||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.
||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.
||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.
||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.
||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.
||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.
||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.
||Change of sonographic findings on cervical lymph nodes before and after preoperative radiotherapy.
||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.