Perfusion CT image of pulmonary thromboembolism: data acquisition using single-detector helical CT scanner

AbstractWe report a case of pulmonary thromboembolism, in which we used conventional single-detector helical CT scanner to obtain dynamic CT data, and the decrease in pulmonary parenchymal perfusion was clearly demonstrated on perfusion CT image

フラットパネルX線ディテクターを用いた関節動態機能診断支援システムの開発

金沢大学医薬保健研究域医学系現在,各種関節を対象としたX線画像検査では,その簡便性と被検者への低侵襲性のために,ほとんど正面像,側面像などの静止画像を撮像して評価している.しかし,多くの関節疾患は当該関節の運動機能を阻害するため,その動態情報を得ることが極めて重要である.我々は,動画対応のフラットパネルX線ディテクタ(FPD)システムを用いて,各種関節の短時間時系列X画像を取得し,それらの動態機能を定量的に解析する方法を開発している.この動態解析の結果を従来の画像検査法から得られる解析結果と比較し,この新しいX線動態検査法が正しい診断情報を提供できるかどうかを検証した.本研究では,開閉口運動における顎関節動態と掌背屈運動における手関節動態を対象として,MRIによる準動態解析の結果と比較検討した.その結果,我々の開発した新X線動態検査法は簡便に運動機能を評価できる有望なスクリーニング画像検査法であることが明らかとなった.たとえば,顎関節について,クリック(顎関節異常の一種)の症状を持つ対象では,MRI検査法でその前方転位が観察されることを推測していた.しかしMR画像上,視覚的な画像所見でも下顎頭の定量的な動態解析結果でも,特にクリックを示唆するような兆候は見られなかった.すなわち,むしろ,関節円板に明らかな異常が認められないような軽微な機能障害は,我々が開発したX線動態検査法の方が検出感度において優れていることが示唆された.研究課題/領域番号:16035206, 研究期間(年度):2004出典：「フラットパネルX線ディテクターを用いた関節動態機能診断支援システムの開発」研究成果報告書　課題番号16035206（KAKEN：科学研究費助成事業データベース（国立情報学研究所））（https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-16035206/)を加工して作

Physiologic-functional Radiography (pfRAD): dynamic imaging for physiological and functional diagnostic information

筆者らは，動画撮影の可能なＸ線フラットパネルディテクタを用いて，様々な生理的情報や機能的情報を取得できるスクリーニング動画像検査法を開発してきた．たとえば短時間時系列の呼吸過程を撮像して，横隔膜の動態解析を行った．また，肺野局所の画素値の変化を解析して，肺換気と胸部循環の概略を評価した．手関節，肩関節，膝関節など四肢関節系については，屈曲と伸展運動中の関節要素の動態変化を定量的に解析して，それらの運動機能を評価した．これらの動画像検査法は，“ コンピュータ解析によって解剖・生理的，機能的情報を付加した一般初期検査としてのＸ線動態機能画像法（physiologic-functional radiography：pfRAD）” という位置づけである．患者被曝線量について，皮膚表面線量は，胸部では 1.9 mGy，股関節では 5.11 mGy と，いずれも国際原子力機関（IAEA）の推奨する線量限度を超えない．本稿では関連する他の研究報告も併せて概説する．We have developed a functional digital radiography system that allows assessment of physiological and functional information of the chest and/or joints using an X-ray flat-panel detector. Sequential chest radiographs are obtained throughout the inspiration and expiration cycle to analyze diaphragmatic movements during chest examination. Ventilation and circulation are analyzed by assessing changes in pixel values in localized areas of the lung. For limb joints, such as the wrist, shoulder, and knee, flexion and extension or rotational movement is assessed using sequential radiographs to analyze movement angles. These imaging techniques and quantitative analyses, referred to as physiologic-functional radiography (pfRAD), provide physiological and functional information. The pfRAD method is promising for screening examinations because of its simplicity and precision. The entrance surface dose for the detector is within the limits recommended by the International Atomic Energy Agency (approximately 1.9 and 5.11 mGy for chest and hip examinations, respectively). Recent relevant studies are reviewed

A computer-aided temporal and dynamic subtraction technique of the liver for detection of small hepatocellular carcinomas on abdominal CT images

金沢大学大学院医学系研究科量子医療技術学It is often difficult for radiologists to identify small hepatocellular carcinomas (HCCs) due to insufficient contrast enhancement. Therefore, we have developed a new computer-aided temporal and dynamic subtraction technique to enhance small HCCs, after automatically selecting images set at the same anatomical position from the present (non-enhanced and arterial-phase CT images) and previous images. The present study was performed with CT images from 14 subjects. First, we used template-matching based on similarities in liver shape between the present (non-enhanced and arterial-phase CT images) and previous arterial-phase CT images at the same position. Temporal subtraction images were then obtained by subtraction of the previous image from the present image taken at the same position of the liver. Dynamic subtraction images were also obtained by subtraction of non-enhanced CT images from arterial-phase CT images taken at the same position of the liver. Twenty-one of 22 nodules (95.5%) with contrast enhancement were visualized in temporal and dynamic subtraction images. Compared with present arterial-phase CT images, increases of 150% and 140% in nodule-to-liver contrast were observed on dynamic and temporal subtraction images, respectively. These subtraction images may be useful as reference images in the detection of small moderately differentiated HCCs. © 2006 IOP Publishing Ltd

Development of a cardiac evaluation method using a dynamic flat-panel detector (FPD) system: A feasibility study using a cardiac motion phantom

金沢大学大学院医学系研究科量子医療技術

Sonographic analysis of hyoid bone movement during swallowing

金沢大学医薬保健研究域保健学系Purpose: Videofluoroscopy is generally considered a "gold standard" technique; however t technique exposes subjects to radiation. Ultrasonography is applied widely in clinical practice because of low cost, safety of the technique, and absence of radiation exposure. The aim of this study was to evaluate hyoid bone movement trajectories during swallowing in healthy subjects using ultrasonography.Subject and Methods: Data were obtained from 15 healthy volunteers (mean age: 34.9± 9.3).The subjects were divided into 3 groups: 5 subjects in their 20s, 5 subjects in their 30s and 5 subjects in their 40s. The subjects were examined while sitting in an upright position, with the back against a wall to control movement. The transducer was placed in a longitudinal scan above the larynx. The hyoid bone was identified on the scan as a high echoic area with posterior acoustic shadow. Then, the subjects swallowed 5 mL of mineral water, with a measurement frequency of 5 times. The digital-ultrasonographic recordings were viewed at 30 frames/s for 3 seconds. Results: The movement was divided into 4 phases: A, slowly ascending phase; B, rapidly ascending phase; C, temporary pause phase (position of maximum rise); D, rapid and slow descending shifts toward the resting position phase. We easily visualized the hyoid bone trajectory using ultrasonography. In all cases, ultrasonographic analysis of the hyoid bone was confirmed to have a similar trajectory as determined with videofluoroscopy. Ultrasonography can accurately determine swallowing duration and trajectory of hyoid bone movement. There was a significant difference in swallowing duration between the 20s groups and 30s groups and between the 20s groups and 40s groups (P < 0.05). However, the difference between the 30s group and 40s group was not significant (P=0.87).Conclusion: The results show that the dynamic phase image of the hyoid bone movement can be revealed by ultrasonographic visualization. © 2009 Springer Berlin Heidelberg