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Comparisons of Image Quality and ADCs in breath-hold, Respiratory-Triggered and Free-breathing DWI of Pancreas at 3-T

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Open Journal of Radiology 2014年第4期4卷 279-292页

作者： Chao Ma Jian Wang Yan-Jun Li Chun-Shu Pan Yong Zhang He Wang Shi-Yue Chen Jian-Ping Lu Department of Radiology Changhai Hospital of Shanghai The Second Military Medical University Shanghai China MR Group GE Healthcare Shanghai China

Objective: To compare image quality and apparent diffusion coefficients (ADC) of the normal pancreas parenchymas in breath-hold, respiratory-triggered and free-breathing diffusion weighted imaging (DWI) at 3.0-Tesla. Methods: DWI of the pancreas was performed at 3.0-Tesla in 21 healthy volunteers with breath-hold, respiratory-triggered and free-breathing using b-values of 0 and 500 s/mm2. For all three sequences, two readers assigned an image quality score to images at b0 and b500, and two independent readers measured ADCs for the head, body and tail of pancreas. Image quality scores and ADCs of pancreas in the three DWIs were compared. Results: For b0, image quality scores was not significantly different among the three sequences (p = 0.103). For b500, image quality score was significantly lower in free-breathing DWI than breath-hold or respiratory-triggered DWI (p = 0.000), and not significantly different between breath-hold and respiratory-triggered DWI (p = 0.212). Mean ADCs differed significantly among the anatomical regions with the lowest values measured in the pancreatic tail both at breath-hold and respiratory-triggered DWIs whereas no significant difference was found at free-breathing DWI. Conclusion: breath-hold or respiratory-triggered technique provided DW images of pancreas with acceptable quality at 3.0-Tesla. breath-hold is the preferred DWI technique for ADC measurements of pancreas.

关键词： DWI ADC breath-hold Respiratory-Triggered Free-breathing Pancreas

A Half-Arc Multiple Deep-Inspiration breath-hold Volumetric Modulated Arc Therapy for a Lung Tumor with 10 MV Flattening-Filter-Free Beams and an Image Sensor Measuring a Distance Map to Thorax Surface: An Initial Clinical Experience

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International Journal of Medical Physics, Clinical Engineering and Radiation Oncology 2017年第1期6卷 31-35页

作者： Keiichi Nakagawa Kanabu Nawa Masatoshi Hashimoto Shuri Aoki Yoshihiro Kaneko Hideomi Yamashita Akihiro Haga Department of Radiology University of Tokyo Hospital Tokyo Japan Department of Radiation Oncology The Cancer Institute Hospital of Japanese Foundation for Cancer Research Tokyo Japan

A technique for multiple deep-inspiration breath-hold (DIBH) volumetric modulated arc therapy (VMAT) for a lung tumor has been proposed with 10 MV flattening-filter-free beams and an image sensor measuring a distance map to thorax surface. Planning CT images were acquired under a DIBH condition and a clinical target volume (CTV) was contoured. This procedure was repeated five times and an internal target volume (ITV) among the multiple DIBHs was created by integrating the five CTVs. A planning target volume (PTV) was defined by adding an isotropic margin of 5 mm to the ITV. Immediately before treatment, a 30-second half-arc cone-beam computer tomography (CBCT) imaging was performed under another DIBH condition, and the couch was repositioned so that tumor may be located inside the PTV contours. An infrared distance measurement device having laser diodes and an image sensor was attached to the couch, and a distance map to the patient thorax surface was recorded as a reference during still another DIBH condition. A half-arc segmented VMAT beams with two beam interrupts were delivered to the patient under multiple DIBHs, where the delivery time of each of the three segmented beams was 30 seconds. During the beam delivery, the distance map was monitored in real time to confirm that the distance to the thorax surface remained unchanged. In-treatment CBCT images suggested that the tumor position at the time of tumor registration was accurately reproduced during the DIBH VMAT delivery.

关键词： Deep Inspiration breath-hold DIBH FFF VMAT Kinect Lung

Usefulness of two-point Dixon fat-water separation technique in gadoxetic acid-enhanced liver magnetic resonance imaging

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World Journal of Gastroenterology 2015年第16期21卷 5017-5022页

作者： Ying Ding Sheng-Xiang Rao Cai-Zhong Chen Ren-Chen Li Meng-Su Zeng Department of Radiology Zhongshan Hospital of Fudan UniversityShanghai Institute of Medical Imaging

AIM:To compare differences between volumetric interpolated breath-hold examination(VIBE) using two-point Dixon fat-water separation(Dixon-VIBE) and chemically selective fat saturation(FS-VIBE) with magnetic resonance imaging ***:Forty-nine patients were included, who were scanned with two VIBE sequences(Dixon-VIBE and FS-VIBE) in hepatobiliary phase after gadoxetic acid *** evaluations including sharpness of tumor, sharpness of vessels, strength and homogeneity of fat suppression, and artifacts that were scored using a 4-point *** liver-to-lesion contrast was also calculated and ***:Dixon-VIBE with water reconstruction had significantly higher subjective scores than FS-VIBE in strength and homogeneity of fat suppression(< 0.0001) but lower scores in sharpness of tumor(P < 0.0001), sharpness of vessels(P = 0.0001), and artifacts(P = 0.034).The liver-to-lesion contrast on Dixon-VIBE images was significantly lower than that on FS-VIBE(16.6% ± 9.4% vs 23.9% ± 12.1%, P = 0.0001).CONCLUSION:Dixon-VIBE provides stronger and more homogenous fat suppression than FS-VIBE, while has lower clarity of focal liver lesions in hepatobiliary phase after gadoxetic acid administration.

关键词： Dixon-volumetric interpolated breath-holdexamination Fat saturation-volumetric interpolatedbreath-hold examination Gadoxetic acid Volumetricinterpolated breath-hold examination Magnetic resonance imaging

Development of forearm impedance plethysmography for the minimally invasive monitoring of cardiac pumping function

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Journal of Biomedical Science and Engineering 2011年第2期4卷 122-129页

作者： Jia-Jung Wang Wei-Chih Hu Tsiar Kao Chun-Peng Liu Shih-Kai Lin 不详

It is essential to continuously and non-invasively monitor the cardiac pumping function in clinical setting. Thus, the study aimed to explore a regional impedance phethysmographic method to assess the changes in stroke volume. To do this, we developed a plethysmographic device that was capable of delivering a single-frequency current with constant amplitude and of recording electrical impedance signals of biological tissue. The electrical impedance plethy- smographic waveform form the lower arm was measured with the impedance plethysmographic device, and simultaneously the end-systolic and end- diastolic volumes of the left ventricle were obtained with a two-dimension echocardiographic system in fourteen healthy subjects before and immediately after a thirty-second breath-hold maneuver. For the 14 subjects, a linear correlation coefficient of 0.79 (p breath-hold test. In addition, the changes in the mean area under the impedance curve and the change in stroke volume were also correlated linearly (r = 0.71, p < 0.005). In summary, the forearm impedance plethysmography may be employed to evaluate the beat-to-beat alteration in cardiac stroke volume, suggesting its potential for long-term monitoring cardiac pumping performance.

关键词： Impedance Plethysmography Stroke Volume breath-hold Maneuver Impedance Echocardiography