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Volume 31 (2014)
- Issue 4 Pages 60-
- Issue 3 Pages 47-
- Issue 2 Pages 28-
- Issue 1 Pages 1-
Volume 31, Issue 1
Displaying 1-5 of 5 articles from this issue
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Invited Lecture
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Tokuo UMEDA, Akiko OKAWA, Tsutomu GOMI, Taku YASHIMAArticle type: Invited Lecture
2014 Volume 31 Issue 1 Pages 1-6
Published: 2014
Released on J-STAGE: March 25, 2014
JOURNAL FREE ACCESSWe present information hiding system developed using digital watermarking and steganography technologies. In digital watermarking technology, chest CT images of 512×512×16bits (67 slices) were used. The EPR data, the hash value of the regions of interest (ROI) , name of the institute, and the data of the patient support system were hidden in the regions of non-interest (RONIs) in a chest CT image series in the Digital and Communication in Medicine (DICOM) format. A body CT image series of 512×512×16 bits (100 slices) was used for steganography. These CT images were stored in a subfolder after 7-Zip compression. This folder was then embedded in the cover image of a scene photograph. The cover image with the embedded images was then transmitted to other medical institutions. In physical evaluation, the structural similarity (SSIM) and the peak signal to noise ratio (PSNR) of the watermarked image with 4000 words embedded were 0.99 and 65.3 dB, respectively. In addition, when the medical information was embedded in the low-bit plane, such as the first- and second-bit plane, the radiologist was unable to identify the embedded information. In our technology, there was no change in the image capacity of CT images or cover image before and after embedding.View full abstractDownload PDF (5843K)
Original Article
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—Visualization of specific muscle activity based on myogenic potential—Saori YOSHINAGA, Eriko KURAMOTO, Hiroe KINOSHITA, Seiji NEMOTOArticle type: Original Article
2014 Volume 31 Issue 1 Pages 7-12
Published: 2014
Released on J-STAGE: March 25, 2014
JOURNAL FREE ACCESSSince shoulder stiffness is characterized by subjective symptoms centered mainly around the trapezius muscle, an objective evaluation may aid in understanding this condition. Thus, assessing the distribution and intensity of muscle activity may help to characterize shoulder stiffness. Using myogenic potential topography, the present study aimed to identify the changes in the state of the trapezius muscle among subjects with shoulder stiffness. Surface electromyogram recordings were obtained from the trapezius region of eight healthy women immediately before exercise, immediately after the end of exercise, and at the end of a 20-min convalescence period. Surface electromyogram data were analyzed by fast Fourier transform (FFT) , and power spectra were obtained. Based on the analyzed data, myogenic potential topography was composed at 6-bit resolution. Women who complained of shoulder stiffness showed remarkable changes in the low-frequency domain of the surface electromyogram immediately after the end of exercise. Further, these changes were in accordance with the positions of the subjective symptoms reported by the subjects. Therefore, these events suggest a phenomenon specific to shoulder stiffness. Visually identifying the physiological alteration of muscle activity is possible using myogenic potential topography.View full abstractDownload PDF (1742K) -
Tsuyoshi MIKAMI, Kazuya YONEZAWA, Yohichiro KOJIMA, Masahito YAMAMOTO, ...Article type: Original Article
2014 Volume 31 Issue 1 Pages 13-18
Published: 2014
Released on J-STAGE: March 25, 2014
JOURNAL FREE ACCESSThis paper proposes an evaluation index for the classification of severe Obstructive Sleep Apnea Syndrome (OSAS) by the use of the tongue morphology and the cross sectional area of the narrowest upper airway evaluated by image analysis on the upper airway MRI. In general, polysomnography (PSG) is a gold standard evaluation for severe SAS, but sometimes the symptoms do not occur during PSG screening because of the first night effect. The morphology of the upper airway, on the other hand, gives much information about the severity of OSAS. So, the upper airway MRI is often used for medical diagnosis, but few evaluation indices have been reported objectively. We focused on the tongue region and considered two directions from the center to the edge of the tongue higher correlated with the severity and determined the cross sectional area in the narrowest upper airway. These features are weighted and linearly combined to predict the severity. Finally, the severe patients are detected by judging whether the prediction value is greater than or equal to 30. As a result, the true positive rate is 0.909 and the false positive rate is 0.476 for detecting the severe patients.View full abstractDownload PDF (3126K) -
Masayuki KANAMOTO, Toshiaki MIYATI, Kazuki TERASHIMA, Kei KATAHIRA, Ry ...Article type: Original Article
2014 Volume 31 Issue 1 Pages 19-23
Published: 2014
Released on J-STAGE: March 25, 2014
JOURNAL FREE ACCESSWe devised a magnetic resonance imaging (MRI) method for visualizing hepatocellular carcinoma (HCC) and vessel thrombus using a three-dimensional balanced sequence (balanced turbo field echo: B-TFE) with a T2 preparation pulse (T2 prep) after enhanced superparamagnetic iron oxide (SPIO) administration. At 1.5T, the following parameters were used: 350mm field of view, 4.3ms repetition time, 2.2ms echo time, 70degree flip angle, 1.0mm slice thickness, and low-to-high k-space profile order. Signal intensity and contrast were assessed in a phantom, and healthy volunteer images were acquired with different prep times. The signal to noise ratio (SNR) was assessed in healthy volunteers. The method was evaluated using optimal prep times from clinical cases: a prep time of 40ms provided the best definition in images of HCC and vessel thrombosis. SPIO-enhanced B-TFE with T2 prep enabled clear and simultaneous visualization of HCC and vessel thrombus.View full abstractDownload PDF (1538K)
Work in Progress
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Tomohiro NODA, Toshiaki MIYATI, Naoki OHNO, Harumasa KASAI, Nobuyuki A ...Article type: Work in Progress
2014 Volume 31 Issue 1 Pages 24-27
Published: 2014
Released on J-STAGE: March 25, 2014
JOURNAL FREE ACCESSTo assess the structure of cancellous tissue in the vertebral bone marrow, we analyzed the restricted diffusion using diffusion kurtosis. On a 1.5T MRI, single-shot diffusion echo planar imaging was used with b values of 0, 20, 120, 500, 1200 and 2200 s/mm2, and a sensitivity encoding technique. Apparent diffusion kurtosis (Kapp) and apparent diffusion coefficient (Dapp) were calculated from diffusion kurtosis analysis based on non-Gaussian diffusion theory. Kapp and Dapp were determined in the lumbar vertebral body of seven normal subjects, and then compared with the bone mineral density (BMD) obtained with dual-energy X-ray absorptiometry. Moreover, fat fraction (FF) of the bone marrow was measured with spectral presaturation with inversion recovery in the same subject. A strong positive correlation was found between Kapp and BMD (R2 = 0.63, P = 0.034) , and FF (R2 = 0.72, P = 0.015) . However, there was no significant correlation between Dapp and BMD, and FF. These results indicating the greater utility of the Kapp than that of the Dapp. Water-restricted diffusion analysis with diffusion kurtosis makes it possible to obtain more detailed information on the structure of cancellous tissue and the bone metabolism.View full abstractDownload PDF (1072K)
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