Details of a Researcher - HATAKENAKA Masamitsu

Papers - HATAKENAKA Masamitsu

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PRETREATMENT APPARENT DIFFUSION COEFFICIENT OF THE PRIMARY LESION CORRELATES WITH LOCAL FAILURE IN HEAD-AND-NECK CANCER TREATED WITH CHEMORADIOTHERAPY OR RADIOTHERAPY

Masamitsu Hatakenaka, Katsumasa Nakamura, Hidetake Yabuuchi, Yoshiyuki Shioyama, Yoshio Matsuo, Kayoko Ohnishi, Shunya Sunami, Takeshi Kamitani, Taro Setoguchi, Takashi Yoshiura, Torahiko Nakashima, Kei Nishikawa, Hiroshi Honda

INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS ( ELSEVIER SCIENCE INC ) 81 ( 2 ) 339 - 345 2011.10 [Refereed]

Purpose: This study was performed to evaluate whether the apparent diffusion coefficient (ADC) of a primary lesion correlates with local failure in primary head-and-neck squamous cell carcinoma (HNSCC) treated with chemoradiotherapy or radiotherapy. Methods and Materials: We retrospectively studied 38 patients with primary HNSCC (12 oropharynx, 20 hypopharynx, 4 larynx, 2 oral cavity) treated with chemoradiotherapy or radiotherapy with radiation dose to gross tumor volume equal to or over 60 Gy and who underwent pretreatment magnetic resonance imaging, including diffusion-weighted imaging. Ten patients developed local failure during follow-up periods of 2.0 to 9.3 months, and the remaining 28 showed local control during follow-up periods of 10.5 to 31.7 months. The variables that could affect local failure (age, tumor volume, ADC, T stage, N stage, dose, treatment method, tumor location, and overall treatment time) were analyzed using logistic regression analyses for all 38 patients and for 17 patients with Stage T3 or T4 disease. Results: In univariate logistic analysis for all 38 cases, tumor volume, ADC, T stage, and treatment method showed significant (p < 0.05) associations with local failure. In multivariate analysis, ADC and T stage revealed significance (p < 0.01). In univariate logistic analysis for the 17 patients with Stage T3 or T4 disease, ADC and dose showed significant (p < 0.01) associations with local failure. In multivariate analysis, ADC alone showed significance (p < 0.05). Conclusions: The results suggest that pretreatment ADC, along with T stage, is a potential indicator of local failure in HNSCC treated with chemoradiotherapy or radiotherapy. (C) 2011 Elsevier Inc.

Diagnostic performance in differentiation of breast lesion on digital mammograms: comparison among hard-copy film, 3-megapixel LCD monitor, and 5-megapixel LCD monitor

Takeshi Kamitani, Hidetake Yabuuchi, Yoshio Matsuo, Taro Setoguchi, Shuji Sakai, Takashi Okafuji, Shunya Sunami, Masamitsu Hatakenaka, Nobuhide Ishii, Makoto Kubo, Eriko Tokunaga, Hidetaka Yamamoto, Hiroshi Honda

CLINICAL IMAGING ( ELSEVIER SCIENCE INC ) 35 ( 5 ) 341 - 345 2011.09 [Refereed]

We compared observer performance of digital mammography among hard-copy readings and soft-copy readings using 3-megapixel (3M) and 5-megapixel (5M) liquid crystal display (LCD) monitors. Five experienced radiologists assessed 80 mammograms of 40 cancers and 40 benign lesions. There were no significant differences among the average A(z) of three modalities and among the kappa values for intra- and interobserver agreement. The soft-copy reading using the 3M LCD monitor took a slightly longer time, although there were no significant differences. (C) 2011 Elsevier Inc. All rights reserved.

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

Toru Chikui, Shintaro Kawano, Toshiyuki Kawazu, Masamitsu Hatakenaka, Syouzou Koga, Masahiro Ohga, Yoshio Matsuo, Syunya Sunami, Tsuyoshi Sugiura, Yoshiyuki Shioyama, Makoto Obara, Kazunori Yoshiura

EUROPEAN RADIOLOGY ( SPRINGER ) 21 ( 8 ) 1699 - 1708 2011.08 [Refereed]

To evaluate whether a pharmacokinetic analysis is useful for both predicting and monitoring the response to chemoradiotherapy (CRT) in oral cancer. Patients with oral squamous cell carcinoma treated with preoperative CRT and surgery were enrolled. They underwent dynamic contrast-enhanced MRI before (n = 23), and after CRT (n = 20). We estimated four parameters: arrival time of contrast medium (TA), exchange rate constant from the extracellular extravascular space (EES) to plasma (k(ep)), elimination of contrast medium from the central compartment (k(el)) and an amplitude scaling constant (AH) using the Brix model. The histological evaluation of the effects of CRT was performed according to Ohboshi and Shimosato's classification. We analysed the correlation between the parameters and the histological evaluation. The pre-CRT AH between the responders and non-responders was significantly different (P = 0.046), however, the three parameters (TA, K-ep, K-el) were not significantly different among the groups (P = 0.76, P = 0.60, P = 0.09). As AH decreased, the tumour response improved. The change in the AH between the pre- and post-CRT of responders was significantly higher than that of non-responders (P = 0.043). The AH, which is affected by the ratio of the EES, was an important parameter for predicting and monitoring the tumour response to CRT.

Correlation between pretreatment or follow-up CT findings and therapeutic effect of autologous peripheral blood stem cell transplantation for interstitial pneumonia associated with systemic sclerosis

Hidetake Yabuuchi, Yoshio Matsuo, Hiroshi Tsukamoto, Shunya Sunami, Takeshi Kamitani, Shuji Sakai, Masamitsu Hatakenaka, Koji Nagafuji, Takahiko Horiuchi, Mine Harada, Koichi Akashi, Hiroshi Honda

EUROPEAN JOURNAL OF RADIOLOGY ( ELSEVIER IRELAND LTD ) 79 ( 2 ) E74 - E79 2011.08 [Refereed]

Purpose: To evaluate what is useful among various parameters including CT findings, laboratory parameters (%VC, %DLco, KL-6), patients related data (age, sex, duration of disease) to discriminate between responder and non-responder in patients who received autologous peripheral blood stem cell transplantation (auto-PBSCT) for interstitial pneumonia (IP) with systemic sclerosis (SSc). Method: Auto-PBSCT and follow-up of at least one year by chest CT, serum KL-6, %VC, and %DLco were performed in 15 patients for IP with SSc. Analyzed CT findings included extent of ground-glass opacity (GGO), intralobular reticular opacity, number of segments that showed traction bronchiectasis, and presence of honeycombing. We regarded the therapeutic response of patients as responders when TLC or VC increase over 10% or DLco increase more than 15%, otherwise we have classified as non-responder. We applied univariate and multivariate analyses to find the significant indicators to discriminate responders from non-responders. P < 0.05 was considered statistically significant. Results: Univariate and multivariate analyses showed that the significant parameter to discriminate responders from non-responders were pretreatment KL-6, presence of honeycombing, extent of GGO, and early change in extent of GGO. Among them, extent of GGO and early change in extent of GGO were the strongest discriminators between responders and non-responders (P = 0.001, 0.001, respectively). Conclusion: Several CT findings and pretreatment KL-6 may be useful to discriminate between responder and non-responder in patients who received auto-PBSCT for IP with SSc. (C) 2011 Elsevier Ireland Ltd. All rights reserved.

Prediction of Local Failures with a Combination of Pretreatment Tumor Volume and Apparent Diffusion Coefficient in Patients Treated with Definitive Radiotherapy for Hypopharyngeal or Oropharyngeal Squamous Cell Carcinoma

Kayoko Ohnishi, Yoshiyuki Shioyama, Masamitsu Hatakenaka, Katsumasa Nakamura, Koichiro Abe, Takashi Yoshiura, Saiji Ohga, Takeshi Nonoshita, Tadamasa Yoshitake, Torahiko Nakashima, Hiroshi Honda

JOURNAL OF RADIATION RESEARCH ( JAPAN RADIATION RESEARCH SOC ) 52 ( 4 ) 522 - 530 2011.07 [Refereed]

Purpose: The purpose of this study was to investigate the clinical factors for predicting local failure after definitive radiotherapy in oropharyngeal or hypopharyngeal squamous cell carcinoma. Materials and Methods: Between July 2006 and December 2008, 64 consecutive patients with squamous cell carcinoma of the hypopharynx or the oropharynx treated with definitive radiotherapy were included in this study. Clinical factors, such as pretreatment hemoglobin (Hb) level, T-stage, gross tumor volume of primary tumors (pGTV), and maximum standardized uptake value (SUV(max)) on FDG-PET, were evaluated for the correlation with local failure. A subset analysis of 32 patients with MR images including diffusion-weighted images (DWI) as a pretreatment evaluation was also performed. The Kaplan-Meier curves, the log-rank test, and the Cox proportional hazards model were used to evaluate these clinical factors. Results: Eleven of 64 patients experienced local recurrence, with a median follow-up time of 15 months. In the univariate analysis, Hb level (p = 0.0261), T-stage (p = 0.012), pGTV (p = 0.0025), and SUV(max) (p = 0.024) were significantly associated with local failure. In the multivariate analysis, pGTV (p = 0.0070) remained an adverse factor for local control. In the subset analysis of 32 patients with DWI, the median apparent diffusion coefficient (ADC) value of primary tumors on DWI was 0.79 x 10(-3) mm(2)/s (range, 0.40-1.60 x 10(-3) mm(2)/s). Patients with a high ADC value (> 0.79 x 10(-3) mm(2)/s) had a significantly lower local control rate than patients with a low ADC value (100% vs. 44%, p = 0.0019). The rate of local failure among patients with a large pGTV and a high ADC value was 55% (6/11), whereas no local failures occurred (0%, 0/21) among patients with a small pGTV or a low ADC. Conclusions: These results suggest that a combination of a large tumor volume and a high ADC value could be predictive of local recurrence after definitive radiotherapy in hypopharyngeal or oropharyngeal squamous cell carcinoma.

A case of localized amyloidosis in the mediastinum, CT, MRI, and 18F-FDG-PET/CT findings

Mikako Jinnouchi, Masamitsu Hatakenaka, Hidetake Yabuuchi, Yoshio Matsuo, Shunya Sunami, Takeshi Kamitani, Masahiro Komori, Yuko Kitajima, Nobuhiro Fujita, Hiroshi Honda

European Journal of Radiology Extra 77 ( 2 ) e39 - e42 2011.02 [Refereed]

Amyloidosis is a heterogeneous group of diseases characterized by the presence of extracellular deposition of amyloid. We present a case of localized amyloidosis of the middle mediastinum, that was diagnosed by trans-esophageal endoscopic ultrasound (EUS)-guided biopsy, focusing on imaging features of contrast-enhanced CT, MRI including dynamic contrast-enhanced study and DWI, and integrated fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/CT. © 2010 Elsevier Ireland Ltd.

Volumetric Asymmetry and Differential Aging Effect of the Human Caudate Nucleus in Normal Individuals: A Prospective MR Imaging Study

Koji Yamashita, Takashi Yoshiura, Akio Hiwatashi, Tomoyuki Noguchi, Osamu Togao, Yukihisa Takayama, Eiki Nagao, Hironori Kamano, Masamitsu Hatakenaka, Hiroshi Honda

JOURNAL OF NEUROIMAGING ( WILEY-BLACKWELL PUBLISHING, INC ) 21 ( 1 ) 34 - 37 2011.01 [Refereed]

PURPOSE The purpose of this study was to examine interhemispheric asymmetry in volume of the caudate nucleus and its age dependency. METHODS High-resolution T1-weighted brain magnetic resonance (MR) images were obtained for each subject using a 3-dimensional fast field-echo pulse sequence. The volumes of the bilateral caudate nuclei on MR images were measured using an automated method. Right-to-left comparison was made using paired t-test. Age-related change of right-to-left volume ratio (R/L ratio) was examined using Pearson's correlation coefficient. RESULTS Fifty healthy right-handed Japanese male subjects (age 12 to 67 years, mean 39.6 years) were involved in this study. The volume of right caudate nucleus was larger than the left in 48 of 50 subjects (P < .001). R/L ratio increased with age (r = .420, P < .01). CONCLUSIONS Our results confirmed the rightward volumetric asymmetry of caudate nucleus in right-handed individuals, and revealed that this asymmetry becomes notable with age.

Detection of non-palpable breast cancer in asymptomatic women by using unenhanced diffusion-weighted and T2-weighted MR imaging: comparison with mammography and dynamic contrast-enhanced MR imaging

Hidetake Yabuuchi, Yoshio Matsuo, Shunya Sunami, Takeshi Kamitani, Satoshi Kawanami, Taro Setoguchi, Shuji Sakai, Masamitsu Hatakenaka, Makoto Kubo, Eriko Tokunaga, Hidetaka Yamamoto, Hiroshi Honda

EUROPEAN RADIOLOGY ( SPRINGER ) 21 ( 1 ) 11 - 17 2011.01 [Refereed]

To compare the detectability of non-palpable breast cancer in asymptomatic women by using mammography (MMG), dynamic contrast-enhanced MR imaging (DCE-MRI) and unenhanced MR imaging with combined diffusion-weighted and T2-weighted images (DWI + T2WI). Forty-two lesions in 42 patients with non-palpable breast cancer in asymptomatic women were enrolled. For the reading test, we prepared a control including 13 normal and 8 benign cases. Each imaging set included biplane MMG, DCE-MRI and DWI + T2WI. Five readers were asked to rate the images on a scale of 0 to 100 for the likelihood of the presence of cancer and the BI-RADS category. Confidence level results were used to construct receiver operating characteristic analysis. Sensitivity and specificity were calculated for each technique. DWI + T2WI showed higher observer performances (area under the curve, AUC, 0.73) and sensitivity (50%) for the detection of non-palpable breast cancer than MMG alone (AUC 0.64; sensitivity 40%) but lower than those of DCE-MRI (AUC 0.93; sensitivity 86%). A combination of MMG and DWI + T2WI exhibited higher sensitivity (69%) compared with that of MMG alone (40%). DWI + T2WI could be useful in screening breast cancer for patients who cannot receive contrast medium and could be used as a new screening technique for breast cancer.

Assessment of the sequential change of the masseter muscle by clenching: A quantitative analysis of T-1, T-2, and the signal intensity of the balanced steady-state free precession

Toru Chikui, Tomoko Shiraishi, Kenji Tokumori, Daisuke Inatomi, Masamitsu Hatakenaka, Kenji Yuasa, Kazunori Yoshiura

ACTA RADIOLOGICA ( ROYAL SOC MEDICINE PRESS LTD ) 51 ( 6 ) 669 - 678 2010.07 [Refereed]

Background: The persistent muscle contractions during clenching are thought to cause some temporomandibular disorders. However, no report has so far evaluated the effect of clenching on the masticatory muscles by magnetic resonance imaging (MRI). Purpose: To investigate the effect of clenching with maximum voluntary contraction on the T-1, T-2, and signal intensity (SI) of the balanced fast field-echo (b FFE) of the masseter muscle. Material and Methods: A total of 11 volunteers participated. Multi-echo spin-echo echo-planar imaging was used for T-2 measurements, and multi-shot Look-Locker sequence for T-1 measurements. The Look-Locker sequence has been used for fast T-1 mapping and this method has been applied for the imaging of various tissues. In addition, the b FFE was used due to the high temporal resolution. These three sequences lasted for 10 min and the participants were instructed to clench from 60 s to 80 s after the start of the data acquisition. T-2, T-1, and SI were normalized compared to pre-clenching values. Results: T-2 decreased by clenching, which reflected a decrease of tissue perfusion due to the mechanical pressure. It increased rapidly after the clenching (peak value, 1.11 +/- 0.03; peak time, 16.8 +/- 7.6 s after the clenching), which corresponded to the reactive hyperemia and later, it gradually returned to the initial values (half period, 2.22 +/- 0.84 min). The change in the SI of the b FFE was triphasic and similar to that of T-2 clenching. T-1 increased after the cessation of the clenching and later gradually decreased during the recovery periods. However, the change of T-1 was quite different from that of T-2, with a lower peak value (1.04 +/- 0.02), a later peak time (36.0 +/- 28.0 s), and a longer half period (4.76 +/- 3.40 min) (P < 0.0001, 0.0066, 0.02, respectively). Conclusion: The change in T-2 was triphasic and we considered that it predominantly reflected the tissue perfusion.

Non-mass-like enhancement on contrast-enhanced breast MR imaging: Lesion characterization using combination of dynamic contrast-enhanced and diffusion-weighted MR images

Hidetake Yabuuchi, Yoshio Matsuo, Takeshi Kamitani, Taro Setoguchi, Takashi Okafuji, Hiroyasu Soeda, Shuji Sakai, Masamitsu Hatakenaka, Makoto Kubo, Eriko Tokunaga, Hidetaka Yamamoto, Hiroshi Honda

EUROPEAN JOURNAL OF RADIOLOGY ( ELSEVIER IRELAND LTD ) 75 ( 1 ) E126 - E132 2010.07 [Refereed]

Purpose: To evaluate the diagnostic accuracy of a combination of dynamic contrast-enhanced MR imaging (DCE-MRI) and diffusion-weighted MR imaging (DWI) in characterization of lesions showing non-mass-like enhancement on breast MR imaging and to find the strongest discriminators between carcinoma and benignancy. Materials and methods: We analyzed consecutive MR images in 45 lesions showing non-mass like enhancement in 41 patients. We analyzed lesion size, distribution, internal enhancement, kinetic curve pattern, and apparent diffusion coefficient (ADC) values. We applied univariate and multivariate analyses to find the strongest indicators for malignancy. In a validation study, 22 non-mass-like enhancement lesions in 21 patients were examined. We calculated diagnostic accuracy when we presume category 4b, 4c, and 5 lesions as malignant or high to moderate suspicion for malignancy, and category 4a and 3 as low suspicion for malignancy or benign. Results: Segmental distribution (P = 0.018), clumped internal enhancement (P = 0.005), and ADC less than 1.3 x 10(-3) mm(2)/s (P = 0.047) were the strongest MR indicators of malignancy. In a validation study, sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 87% (13/15), 86% (6/7), 93% (13/14), 75% (6/8) and 86% (19/22), respectively. Conclusion: The combination of DCE-MRI and DWI showed high diagnostic accuracy in characterization of non-mass-like enhancement lesions on breast MR images. (C) 2009 Elsevier Ireland Ltd. All rights reserved.

[Future of diagnostic radiology: prediction of treatment outcome using MRI].

Hatakenaka M, Yoshiura T, Shioyama Y, Honda H

Fukuoka igaku zasshi = Hukuoka acta medica ( 3 ) 101 41 - 45 2010.03 [Refereed]

Detection of Hepatocellular Carcinoma (HCC) Using Super Paramagnetic Iron Oxide (SPIO)-Enhanced MRI: Added Value of Diffusion-Weighted Imaging (DWI)

Akihiro Nishie, Tsuyoshi Tajima, Kousei Ishigami, Yasuhiro Ushijima, Daisuke Okamoto, Masakazu Hirakawa, Yunosuke Nishihara, Akinobu Taketomi, Masamitsu Hatakenaka, Hiroyuki Irie, Kengo Yoshimitsu, Hiroshi Honda

JOURNAL OF MAGNETIC RESONANCE IMAGING ( JOHN WILEY & SONS INC ) 31 ( 2 ) 373 - 382 2010.02 [Refereed]

Purpose: To evaluate whether diffusion-weighted imaging (DWI) improves the detection of hepatocellular carcinoma (HCC) on super paramagnetic iron oxide (SPIO)-enhanced MRI. Materials and Methods: This retrospective study group consisted of 30 patients with 50 HCC nodules who underwent MRI at 1.5 Tesla. Two combined MR sequence sets were compared for detecting HCC: SPIO-enhanced MRI (axial T2-weighted fast spin-echo (FSE) and T1-/T2*-weighted fast field echo (FFE) scanned before and after administration of ferucarbotran) and SPIO-enhanced MRI + DWI (SPIO-enhanced MRI With axial DWI scanned before and after administration of ferucarbotran). Three blinded readers independently reviewed for the presence of HCC on a segment-by-segment basis using a four-point confidence scale. The performance of the two combined MR sequence sets was evaluated using receiver operating characteristic (ROC) analysis. Results: The average area under the ROC curve (Az) of the three readers for the SPIO-enhanced MRI + DWI set (0.870 +/- 0.046) was significantly higher that that for the SPIO-enhanced MRI set (0.820 +/- 0.055) (P = .025). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for detection of HCC were 66.0%, 98.0%, 90.0%, and 91.4%, respectively, for the SPIO-enhanced MRI set, and 70.0%, 98.6%, 92.9%, and 92.4%, respectively, for the SPIO-enhanced MRI + DWI set. Conclusion: The SPIO-enhanced MRI + DWI set outperformed the SPIO-enhanced MRI set for depicting HCC.

Detection of breast cancer by soft-copy reading of digital mammograms: Comparison between a routine image-processing parameter and high-contrast parameters

Takeshi Kamitani, Hidetake Yabuuchi, Hiroyasu Soeda, Yoshio Matsuo, Takashi Okafuji, Shuji Sakai, Taro Setoguchi, Masamitsu Hatakenaka, Nobuhide Ishii, Hiroshi Honda

ACTA RADIOLOGICA ( TAYLOR & FRANCIS LTD ) 51 ( 1 ) 15 - 20 2010.02 [Refereed]

Background: Recent studies have reported the clinical usefulness of the soft-copy reading of mammograms. However, image-processing parameters for soft-copy reading of digital mammograms have not been established. Purpose: To compare observer performance in detecting breast cancer by soft-copy reading of digital mammograms using a routine image-processing parameter versus each of several high-contrast parameters. Material and Methods: The mammograms of 154 breasts, including 48 abnormal breasts with breast cancer and 106 normal breasts, were examined. Cancers were classified into 34 mass-dominant cancers, 11 microcalcification-dominant cancers, two cancers showing only architectural distortion, and one cancer without abnormal findings. All mammograms were performed using a computed radiography (CR) system. Each image was processed using GA (1.2), which was the contrast parameter recommended by the manufacturer for hard-copy film, GA (1.4), GA (1.6), and GA (1.8). These images were displayed on 5-megapixel (M) liquid-crystal display monitors. Five experienced radiologists classified them into BI-RADS category 1-2 or 3-5, and were also asked to rate the images on a scale of 0 to 100 for the likelihood of the presence of masses and microcalcifications in each breast. Results: In mass-dominant cancers of dense breast tissue, the mean sensitivities of GA (1.2), GA (1.4), GA (1.6), and GA (1.8) were 32.7, 38.2, 36.4, and 40.0, and the A(Z) values were 0.67, 0.73, 0.71, and 0.73, respectively; in microcalcification-dominant cancers, the mean sensitivities were 80.0, 74.5, 80.0, and 78.2, respectively; however, there were no significant differences among them. Conclusion: High-contrast parameters tended to show relatively high sensitivity and A(Z) values in the detection of masses in dense breast tissue, but relatively low sensitivity for microcalcifications.

Can calcification predict I-131 accumulation on metastatic lymph nodes in papillary thyroid carcinoma patients receiving I-131 therapy? Comparison of CT, I-131 WBS and F-18-FDG PET/CT

Koichiro Kaneko, Koichiro Abe, Shingo Baba, Yoshitaka Tanabe, Hidetake Yabuuchi, Masamitsu Hatakenaka, Masayuki Sasaki, Hiroshi Honda

EUROPEAN RADIOLOGY ( SPRINGER ) 20 ( 2 ) 477 - 483 2010.02 [Refereed]

The aim of this study was to clarify the predictive significance of nodal calcification in terms of the therapeutic option of I-131 therapy in papillary thyroid carcinoma (PTC) patients. We reviewed 19 computed tomography (CT) examinations of PTC patients on receiving I-131 therapy for the presence of nodal calcification, and compared the I-131 whole-body scintigraphy and F-18-2-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET)/CT findings. The metastatic lymph nodes (mLNs) were divided into three groups: A, those with calcification; B, those without calcification but belonging to patients who had calcified mLNs; C, those without calcification and belonging to patients who had no calcified mLNs. The incidences of I-131 accumulation and maximum standardised uptake values (SUV max) in the three groups were compared. A total of 70 mLNs were evaluated. Twelve mLNs belonged to group A, 13 to group B and 45 to group C. The incidences of I-131 accumulation were significantly higher in groups A (100%) and B (100%) than in group C (11.1%) (p < 0.0001 for both). The SUVmax was significantly lower in groups A (4.1 +/- 1.9) and B (3.9 +/- 1.4) than in group C (7.1 +/- 4.4) (p = 0.01, p = 0.002, respectively). Our results indicated that calcification in mLNs related to the ability of I-131 accumulation and less dedifferentiation.

Joint Position Affects Muscle Proton Diffusion: Evaluation With a 3-T MR System

Masamitsu Hatakenaka, Hidetake Yabuuchi, Shunya Sunami, Takeshi Kamitani, Yukihisa Takayama, Kei Nishikawa, Hiroshi Honda

AMERICAN JOURNAL OF ROENTGENOLOGY ( AMER ROENTGEN RAY SOC ) 194 ( 2 ) W208 - W211 2010.02 [Refereed]

OBJECTIVE. To determine whether joint position affects muscle proton diffusion, fractional anisotropy and primary (lambda(1)), secondary (lambda(2)), and tertiary (lambda(3)) eigenvalues of calf muscles were compared among ankle positions of plantar flexion, intermediate, and dorsiflexion. CONCLUSION. In tibialis anterior, fractional anisotropy and lambda(1) decreased, but lambda(2) and lambda(3) increased (p < 0.01) as the joint angle increased. Opposite results were obtained for the gastrocnemius and soleus (p < 0.05). These results indicate that joint position affects muscle proton diffusion.

Effect of clenching on T-2 and diffusion parameters of the masseter muscle

Toru Chikui, Tomoko Shiraishi, Takahiro Ichihara, Toshiyuki Kawazu, Masamitsu Hatakenaka, Yukiko Kami, Kenji Yuasa, Kazunori Yoshiura

ACTA RADIOLOGICA ( ROYAL SOC MEDICINE PRESS LTD ) 51 ( 1 ) 58 - 63 2010.02 [Refereed]

Background: Persistent muscle contractions during clenching are considered to be one reason for temporomandibular disorders. However, no report has evaluated the effect of clenching on the masticatory muscles, as measured by magnetic resonance imaging (MRI). Purpose: To investigate whether clenching has an effect on either T-2 or the coefficients for diffusion of the masseter muscles (MM), and to evaluate the effect of the distribution of bite force on such indices. Material and Methods: Twenty-three subjects were examined. Bite force was measured by a pressure-sensitive sheet, and the force of the right and the left sides was calculated. MRI was used to evaluate T-2, the apparent diffusion coefficient (ADC), and the primary (lambda 1), secondary (lambda 2),and tertiary eigenvalues (lambda 3). These indices on the stronger side of the bite force were compared to those on the weaker side. Thereafter, the indices were compared between at rest and during clenching. Results: There was no significant difference in any of the indices (T-2, ADC, lambda 1, lambda 2, and lambda 3) between the side of stronger bite force and the side with weaker. T-2 increased by clenching, and the difference was significant in the side with stronger bite force (P = 0.006). ADC, lambda 1, lambda 2, and lambda 3 increased significantly by clenching (P < 0.01, P < 0.01, P < 0.01, and P < 0.01, respectively) on both sides. The percentage of change of lambda 2 by clenching was 26.2 +/- 15.7% on the stronger side and 26.9 +/- 18.6% on the weaker side, which was significantly greater than either that of lambda 1 or lambda 3. Conclusion: The coefficients for diffusion of the MM were sensitive to change by clenching, and lambda 2 was the most sensitive. Moreover, the relative distribution of the bite forces had no effect on any of the indices.

Detection of Residual Lymph Node Metastases in High-Risk Papillary Thyroid Cancer Patients Receiving Adjuvant I-131 Therapy The Usefulness of F-18 FDG PET/CT

Koichiro Kaneko, Koichiro Abe, Shingo Baba, Takuro Isoda, Hidetake Yabuuchi, Masayuki Sasaki, Masamitsu Hatakenaka, Hiroshi Honda

CLINICAL NUCLEAR MEDICINE ( LIPPINCOTT WILLIAMS & WILKINS ) 35 ( 1 ) 6 - 11 2010.01 [Refereed]

Objective: The aims of this retrospective study were to evaluate the incidence of residual lymph node (LN) metastases in high-risk papillary thyroid cancer (PTC) patients receiving adjuvant I-131 therapy, especially in those without I-131 accumulation, and to evaluate the clinical usefulness of F-18 FDG PET/CT to detect those lesions. Methods: The 37 PTC patients receiving adjuvant I-131 therapy were retrospectively evaluated. We examined the incidence of residual LN metastasis and compared the accumulation of F-18 FDG and I-131 in those lesions, and compared the serum thyroglobulin (Tg) levels between patients with and without residual LN metastases. Result: A total of 33 lesions were diagnosed as residual LN metastases in 9 patients. FDG accumulated in all of the lesions, but 19 lesions (57.6%) of them had no I-131 accumulation. The SUVmax was significantly higher in lesions without I-131 accumulation than in lesions with I-131 accumulation (6.6 +/- 2.8 vs. 4.2 +/- 1.8; P = 0.007). The serum Tg levels were significantly higher in patients with residual LN metastases than in patients without it (709.9 +/- 1470.8 vs. 25.6 +/- 37.1 ng/mL; P = 0.005). The incidence of residual LN metastasis was significantly higher in patients with a detectable serum Tg level than in patients without it (35.0% vs. 0%, P = 0.03). Conclusion: These results indicate that the residual LN metastasis was relatively common in high-risk PTC patients receiving adjuvant I-131 therapy whose serum Tg levels remained detectable, and those lesions often had no I-131 accumulation, FDG-PET/CT would be recommended for PTC patients with detectable serum Tg levels to detect residual LN metastases.

A Simplified Method of T-1 rho Mapping in Clinical Assessment of Knee Joint

Yukihisa Takayama, Masamitsu Hatakenaka, Takashi Yoshiura, Ken Okazaki, Kei Nishikawa, Tomoyuki Okuaki, Ivan Zimine, Hiroshi Honda

MAGNETIC RESONANCE IN MEDICAL SCIENCES ( JPN SOC MAGNETIC RESONANCE IN MEDICINE ) 9 ( 4 ) 209 - 215 2010 [Refereed]

Purpose: We assessed the clinical utility of our proposed simplified method for T-1 rho mapping calculations. Materials and Methods: Ten healthy subjects underwent scanning on a 3-tesla magnetic resonance system using an 8-channel phased-array coil. For each subject, we obtained sagittal T-1 rho-prepared images using 5 different time of spin-lock pulses (TSL = 1, 20, 40, 60, and 80 ms), produced conventional T-1 rho maps (cT(1)rho maps) using all TSLs, and recomputed our proposed simplified T-1 rho maps (sT(1)rho maps) using a decreasing number of TSLs (from 4 to 2). We then investigated the differences and correlations in T-1 rho values of the tissues obtained using different numbers of spin-lock times. Results: There was a strong positive correlation (single measure intraclass correlation coefficient = 0.948; 95% confidence interval = 0.911 to 0.970) in T-1 rho values of tissues between the cT(1)rho and sT(1)rho [1, 80] maps. The 2 maps were comparable, though there was a small difference in T-1 rho value between the two. The total scan time to acquire the data from 5 spin-lock times was 16 min 15 s. Similarity of the T-1 rho [1, 80] map with the conventional approach reduced scan time by 60%, to 6 min 30 s. Conclusion: The clinical relevance of our proposed simplified method is potentially similar to that of the conventional method, and our method requires a shorter examination time and generally preserves the reliability of the T-1 rho relaxation time of the tissues.

A fast Look-Locker method for T (1) mapping of the head and neck region

Toru Chikui, Kenji Tokumori, Ryosuke Zeze, Tomoko Shiraishi, Takahiro Ichihara, Masamitsu Hatakenaka, Kazunori Yoshiura

ORAL RADIOLOGY ( SPRINGER ) 25 ( 1 ) 22 - 29 2009.06 [Refereed]

A sequence for T (1) relaxation time measurements that allows a high-resolution image to be obtained within a short acquisition time is described. Its application to the orofacial region is investigated. The sequence is based on the Look-Locker (LL) method and employs a magnetization-preparation pulse prior to data acquisition, with either a turbo-field echo (TFE) or turbo-field echo echo-planar imaging (TFEPI) sequence. We applied the multiple LL sequence by synchronizing the data acquisition with the virtual electrocardiogram. T (1) results from the LL sequence were compared with those from the inversion recovery (IR) sequence. In an in vitro study, we evaluated the T (1) maps of contrast medium at different concentrations. In an in vivo study, we evaluated the T (1) maps in seven volunteers. In the in vitro study, the correlation between the T (1) values obtained from the LL sequence and those from the IR sequence was high, with an R (2) of more than 0.99. For T (1) values between 200 and 1,500 ms, the difference between the two methods was less than 7%. In the in vivo study, a high correlation was observed between the T (1) values from the IR sequence and those from the LL sequence. The scan duration for the LL sequence was less than 3 min. Our method, based on the LL sequence, was found to be clinically useful for producing a T (1) map.

Nonspecific Interstitial Pneumonia After Peripheral Blood Stem Cell Transplantation in an 11-year-old boy

Keiji Matsumoto, Hidetake Yabuuchi, Yoshio Matsuo, Takeshi Kamitani, Taro Setoguchi, Shuji Sakai, Masamitsu Hatakenaka, Aiko Suminoe, Ichiro Yoshino, Masazumi Tsuneyoshi, Hiroshi Honda

JOURNAL OF THORACIC IMAGING ( LIPPINCOTT WILLIAMS & WILKINS ) 24 ( 1 ) 59 - 61 2009.02 [Refereed]

Late-onset pulmonary complications after peripheral blood stem cell transplantation include various conditions such as opportunistic infection, and interstitial pneumonias. It is Sometimes difficult to diagnose interstitial pneumonia, because there is substantial overlap in their computed tomography appearances. We present a case of an 11-year-old boy who consecutively developed pulmonary infection and cellular nonspecific interstitial pneumonia 9 months after peripheral blood stem cell transplantation for recurrent acute lymphocytic leukemia.

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