Kikuchi M.,Gunma Prefectural College of Health Sciences
Nihon Hoshasen Gijutsu Gakkai zasshi | Year: 2016
During the arterial phase acquisition of Gd-EOB-DTPA examinations, use of a small volume of the Gd-EOB-DTPA may make it difficult the encoding center of the k-space, and produce blurring. The previous studies revealed the encoding technique of the k-space was one of the most important reasons. However, there is no report to discuss the reasons with quantitative evaluations. The purpose of this study was to quantitatively evaluate the characteristics of the artifacts using different k-space encoding techniques (centric-view ordering (CVO) and sequential-view ordering (SVO)) for liver dynamic MRI in computer simulation study. This simulation study consists of the following steps. First of all, the creation of a time intensity curve, and original simulation images at certain points among the one phase dynamic scanning. Secondly, creation-simulated MR echo data from the created original images using FFT, and encoding simulated k-space using the simulated MR echo data. Finally, a reconstruction of simulated dynamic MR images from the simulated k-space, and to evaluate each simulated MR images, we measured modulation transfer functions (MTFs) from the bar patterns of the reconstructed images. The results of the CVO simulation indicated that the bar patterns were blurring compared to the images encoded by the SVO. The results of the SVO simulation indicated that the bar patterns were not enhanced at late scan timings. In addition, the results of MTFs indicated that there was no edge enhancement at all scan timings and both encoding techniques. In conclusion, it is possible to quantitatively evaluate the characteristics of artifacts using MTF, which was measured by the bar patterns, in liver dynamic MRI.
Mariani G.,University of Pisa |
Bruselli L.,University of Pisa |
Kuwert T.,Friedrich - Alexander - University, Erlangen - Nuremberg |
Kim E.E.,University of Texas M. D. Anderson Cancer Center |
And 5 more authors.
European Journal of Nuclear Medicine and Molecular Imaging | Year: 2010
In the era when positron emission tomography (PET) seems to constitute the most advanced application of nuclear medicine imaging, still the conventional procedure of single photon emission computed tomography (SPECT) is far from being obsolete, especially if combined with computed tomography (CT). In fact, this dual modality imaging technique (SPECT/CT) lends itself to a wide variety of useful diagnostic applications whose clinical impact is in most instances already well established, while the evidence is growing for newer applications. The increasing availability of new hybrid SPECT/CT devices with advanced technology offers the opportunity to shorten acquisition time and to provide accurate attenuation correction and fusion imaging. In this review we analyse and discuss the capabilities of SPECT/CT for improving sensitivity and specificity in the imaging of both oncological and non-oncological diseases. The main advantages of SPECT/CT are represented by better attenuation correction, increased specificity, and accurate depiction of the localization of disease and of possible involvement of adjacent tissues. Endocrine and neuroendocrine tumours are accurately localized and characterized by SPECT/CT, as also are solitary pulmonary nodules and lung cancers, brain tumours, lymphoma, prostate cancer, malignant and benign bone lesions, and infection. Furthermore, hybrid SPECT/CT imaging is especially suited to support the increasing applications of minimally invasive surgery, as well as to precisely define the diagnostic and prognostic profile of cardiovascular patients. Finally, the applications of SPECT/CT to other clinical disorders or malignant tumours is currently under extensive investigation, with encouraging results in terms of diagnostic accuracy. © Springer-Verlag 2010.
Matsuzaki T.,Gunma University |
Yaguchi T.,Gunma University |
Shimizu K.,Gunma University |
Kita A.,Gunma University |
And 2 more authors.
Anatomical Science International | Year: 2016
The membrane water channel aquaporin (AQP) family is composed of 13 isoforms in mammals, eight of which are reportedly expressed in the kidney: AQP1, 2, 3, 4, 6, 7, 8, and 11. These isoforms are differentially expressed along the renal tubules and collecting ducts. AQP1 and 7 are distributed in the proximal tubules, whereas AQP2, 3, and 4 occur in the collecting duct system. They play important roles in the reabsorption of water and some solutes across the plasma membrane. In contrast to other aquaporins found in the kidney, AQP6, 8, and 11 are localized to the cytoplasm rather than to the apical or basolateral membranes. It is therefore doubtful that these isoforms are directly involved in water or solute reabsorption. AQP6 is localized in acid-secreting type A intercalated cells of the collecting duct. AQP8 has been found in the proximal tubule but its cellular location has not yet been defined by immunohistochemistry. AQP11 seems to be localized in the endoplasmic reticulum (ER) of proximal tubule cells. Interestingly, polycystic kidneys develop in AQP11-null mice. Many vacuole-like structures are seen in proximal tubule cells in kidneys of newborn AQP11-null mice. Subsequently, cysts are generated, and most of the mice die within a month due to severe renal failure. Although ER stress and impairment of polycystin-1, the product of the gene mutated in autosomal-dominant polycystic kidney disease, are possible causes of cystogenesis in AQP11-null mice, the exact mechanism of pathogenesis and the physiological function of AQP11 are yet to be resolved. © 2016 Japanese Association of Anatomists
Hayashi N.,Gunma Prefectural College of Health Sciences
Nihon Hoshasen Gijutsu Gakkai zasshi | Year: 2014
Digital chest phantoms continue to play a significant role in optimizing imaging parameters for chest X-ray examinations. The purpose of this study was to develop a digital chest phantom for studies on energy subtraction techniques under ideal conditions without image noise. Computed tomography (CT) images from the LIDC (Lung Image Database Consortium) were employed to develop a digital chest phantom. The method consisted of the following four steps: 1) segmentation of the lung and bone regions on CT images; 2) creation of simulated nodules; 3) transformation to attenuation coefficient maps from the segmented images; and 4) projection from attenuation coefficient maps. To evaluate the usefulness of digital chest phantoms, we determined the contrast of the simulated nodules in projection images of the digital chest phantom using high and low X-ray energies, soft tissue images obtained by energy subtraction, and "gold standard" images of the soft tissues. Using our method, the lung and bone regions were segmented on the original CT images. The contrast of simulated nodules in soft tissue images obtained by energy subtraction closely matched that obtained using the gold standard images. We thus conclude that it is possible to carry out simulation studies based on energy subtraction techniques using the created digital chest phantoms. Our method is potentially useful for performing simulation studies for optimizing the imaging parameters in chest X-ray examinations.
Hikosaka K.,Osaka University |
Watanabe Y.-I.,University of Tokyo |
Kobayashi F.,Kyorin University |
Waki S.,Gunma Prefectural College of Health Sciences |
And 2 more authors.
Parasitology International | Year: 2011
Mitochondrial (mt) genomes from diverse phylogenetic groups vary considerably in size, structure and organization. The genus Plasmodium, the causative agent of malaria, has the smallest mt genome in the form of a tandemly repeated, linear element of 6. kb. The Plasmodium mt genome encodes only three protein genes (cox1, cox3 and cob) and large- and small-subunit ribosomal RNA (rRNA) genes, which are highly fragmented with 19 identified rRNA pieces. The complete mt genome sequences of 21 Plasmodium species have been published but a thorough investigation of the arrangement of rRNA gene fragments has been undertaken for only Plasmodium falciparum, the human malaria parasite. In this study, we determined the arrangement of mt rRNA gene fragments in 23 Plasmodium species, including two newly determined mt genome sequences from P. gallinaceum and P. vinckei vinckei, as well as Leucocytozoon caulleryi, an outgroup of Plasmodium. Comparative analysis reveals complete conservation of the arrangement of rRNA gene fragments in the mt genomes of all the 23 Plasmodium species and L. caulleryi. Surveys for a new rRNA gene fragment using hidden Markov models enriched with recent mt genome sequences led us to suggest the mtR-26 sequence as a novel candidate LSU rRNA fragment in the mt genomes of the 24 species. Additionally, we found 22-25. bp-inverted repeat sequences, which may be involved in the generation of lineage-specific mt genome arrangements after divergence from a common ancestor of the genera Eimeria and Plasmodium/. Leucocytozoon. © 2011 Elsevier Ireland Ltd.
Kano T.,Gunma Prefectural College of Health Sciences |
Kanda K.,Gunma University
Kitakanto Medical Journal | Year: 2011
Purpose: To categorize taste changes experienced by chemotherapy patients, the influence of such changes on daily life, and coping mechanisms adopted. Subjects and Methods: Eight chemotherapy patients experiencing taste changes participated in a semi-structured interview. Interview data was categorized according to content similarities for symptom characteristics, adverse effects on daily life, and coping mechanisms. Results: Characteristic symptoms were: [taste changes], such as "hypogeusia", "phantogeusia", and "heterogeusia"; [discomfort] such as nausea in general and nausea caused specifically by smells; and [alteration of oral function] as in dryness of the mouth. Regarding the adverse effects of the symptoms, patients selected [psychological challenges] due to the unpleasant taste of food, [social challenges] due to inconvenience when seasoning meals or dining out, [coping mechanisms] such as being creative with food and distractors, and [support mechanisms] involving family members. To be creative with food, patients practiced "adding more sour tastes to food", "eating sweets", "eating potatoes", "avoiding odors", "avoiding bitter tastes", and "focusing on food and timing of meals" Conclusion: Because taste changes present physical, psychological, and social challenges to patients and necessitate that they develop coping skills and support systems, the condition should be regarded as a compulsory subject in chemotherapy nursing.
Takahashi Y.,Gunma Prefectural College of Health Sciences |
Miyagawa M.,Ehime University |
Nishiyama Y.,Ehime University |
Ishimura H.,Ehime University |
Mochizuki T.,Ehime University
Annals of Nuclear Medicine | Year: 2013
Objective: The performance of a new single photon emission computed tomography (SPECT) scanner with a cadmium-zinc-telluride (CZT) solid-state semiconductor detector (Discovery NM 530c; D530c) was evaluated and compared to a conventional Anger-type SPECT with a dual-detector camera (Infinia). Methods: Three different phantom studies were performed. Full width at half maximum (FWHM) was measured using line sources placed at different locations in a cylindrical phantom. Uniformity was measured using cylindrical phantoms with 3 different diameters (80, 120, and 160 mm). Spatial resolution was evaluated using hot-rod phantoms of various diameters (5, 9, 13, 16, and 20 mm). Three different myocardial phantom studies were also performed, acquiring projection data with and without defects, and evaluating the interference of liver and gallbladder radioactivity. In a clinical study, the D530c employed list-mode raw data acquisition with electrocardiogram (ECG)-gated acquisition over a 10-min period. From the 10-min projection data, 1-, 3-, 5-, 7- and 10-min SPECT images were reconstructed. Results: The FWHM of the D503c was 1.73-3.48 mm (without water) and 3.88-6.64 mm (with water), whereas the FWHM of the Infinia was 8.17-12.63 mm (without water) and 15.48-16.28 mm (with water). Non-uniformity was larger for the D530c than for the Infinia. Truncation artifacts were also observed with the D530c in a Φ160 mm phantom. The contrast ratio, as defined by myocardial defect/non-defect ratio, was better for the D530c than for the Infinia, and the influence from liver and gallbladder radioactivities was less. Quantitative gated SPECT (QGS) software demonstrated significant differences between data captured over a 10-min period, relative to those acquired over periods of <5 min; there was no difference between ejection fractions calculated using data capture for periods ≥5 min (p < 0.05). Conclusions: The D530c is superior to the Infinia, with regard to both spatial resolution and sensitivity. In this study, these advantages were confirmed by the myocardial phantom and in a clinical setting, using the QGS software. © 2012 The Author(s).
Igarashi H.,Gunma Prefectural College of Health Sciences
Nihon Hoshasen Gijutsu Gakkai zasshi | Year: 2014
To prevent the recurrence of irradiation accidents, monitor-unit (MU) verification that is independent of the MU values calculated using the radiation treatment planning system (RTPS) is required. In this study, we investigated whether independent verification of MU values is being conducted in medical settings and examined the types and methods used. Our results indicate that 93.8% of facilities conduct independent MU verification. The methods used vary according to the facility: 30.4% conduct actual measurements, 18.6% use MS-Excel calculation sheets, 16.7% use specialized commercially-available software, 14.7% use spreadsheets 13.7% use calculators, and 5.9% use other methods. In this study, we were able to formulate basic data that can be used for information-sharing between facilities.
Ishizaka H.,Maebashi Redcross Hospital |
Shiraishi A.,Gunma Prefectural College of Health Sciences |
Awata S.,Gunma University |
Shimizu A.,Gunma University |
Hirasawa S.,Gunma University
British Journal of Radiology | Year: 2011
Thermal tumour ablation techniques such as radiofrequency (RF) ablation are applied for radical removal of local tumours as an easier, less invasive alternative to surgical resection. A serious drawback of thermal ablation, however, is that the ablation area cannot be accurately assessed during the procedure. To achieve real-time feedback and exact and safe ablation, a superfine thermocouple-needle system (TNS) comprising a 0.25-mm diameter thermocouple embedded in a 22-G, 15-cm-long needle was devised and efficacy was tested in vitro using porcine livers (n=15) and in vivo using rabbit back muscles (n=2) and livers (n=3). A 17-gauge RF electrode with a 2 cm active tip was used for ablation. The TNS was inserted 1 cm from the active tip of the RF electrode and liver temperature around the electrode was measured concurrently. The RF current was cut off when the temperature reached 60°C or after 5 min at ≥50°C. Porcine livers and rabbit back muscles were then cut along a plane passing through the axes of the electrode and the TNS. In rabbit livers, contrast-enhanced CT was performed to evaluate ablation areas. Ablation areas in cut surfaces of porcine livers exhibited well-defined discoloured regions and the TNS tip precisely pinpointed the margin of the ablation area. Contrast-enhanced CT of rabbit livers showed the TNS tip accurately located at the margin of areas without contrast enhancement. These results indicate that the TNS can accurately show ablation margins and that placing the TNS tip at the intended ablation margin permits exact thermal ablation. © 2011 The British Institute of Radiology.
Nagashima H.,Gunma Prefectural College of Health Sciences
Nihon Hoshasen Gijutsu Gakkai zasshi | Year: 2011
In diagnostic brain computed tomography (CT) imaging of hyperacute ischemic stroke, the recognition of subtle lesions is difficult and may be missed. The aim of this study was to evaluate quantitatively the effect of the window width on low contrast detectability by using digital phantom images intended for detection of hyperacute ischemic stroke, and clinical CT images. We first derived the digital phantom images by subtracting the simulated signal data (intensity=1-3 hounsfield units (HU), diameter=10-30 mm) from the water phantom images at various mAs values. Observer studies were then performed under the various window widths at 20, 40, 60, and 80 HU by using the 30 digital phantom images and the 30 water phantom images. In addition, observer studies on brain CT images with 30 abnormal cases and 30 normal cases were performed under the window widths at 20 and 80 HU. Studies were also performed under the simultaneous display of the set of brain CT images on each window width. As a result of evaluation by receiver operating characteristic analysis, narrowing of the window width can improve the low contrast detectability in CT images with noticeable noise, and can decrease the variation in the interpretation skills between observers in clinical CT images. Moreover, the interpretation accuracy was improved by displaying simultaneously the clinical CT image set on window widths at 20 and 80 HU.