• Journal of Biomedical Engineering Research
• /
• v.26 no.5
• /
• pp.295-300
• /
• 2005

We introduce an x-ray micro tomography system capable of high resolution imaging of a local region inside a small animal. By combining two kinds of projection data, one from a full field-of-view (FOV) scan of the whole body and the other from a limited FOV scan of the region of interest, we have obtained zoomed-in images of the region of interest without any contrast a nomalies. We have integrated a micro tomography system using a micro-focus x-ray source, a $1248\times1248$ flat-panel x-ray detector, and a precision scan mechanism. Using the cross-sectional images taken with the zoom-in micro tomography system, we measured trabecular thicknesses of femur bones in postmortem rats. To compensate the limited spatial resolution in the zoom-in micro tomography images, we used the fuzzy distance transform for the calculation of the trabecular thickness. To validate the trabecular thickness measurement with the zoom-in micro tomography images, we compared the measurement results with the ones obtained from the conventional micro tomography images of the extracted bone samples.

• Proceedings of the Korean Society of Medical Physics Conference
• /
• 2002.09a
• /
• pp.365-366
• /
• 2002

A novel TEM resonator coil was developed for the imaging of small animals. The functional elements of the TEM resonator were 8 inner conductors, distributed in a cylindrical pattern and connected at the ends with capacitors to the cylindrical outer shield. The TEM resonator coil with cavity elements was robust to the surrounding influences due to the self-shielding structure. The TEM resonator coil with high Q factor could provide high quality MR images at 3.0T MRI system. Also, the TEM resonator coil has an advantage for a fine tune with length adjustment of each cavity elements. Thus, The TEM resonator coil at 3.0T, even higher field could be used in the research studies.

• Animal cells and systems
• /
• v.15 no.1
• /
• pp.53-61
• /
• 2011

The fine structural characteristics of the antennal sensory organs of a female millipede Oxidus gracilis (Polydesmida: Paradoxomatidae) were observed with both field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). We could identify four apical cones and three basic types of antennal sensillae in a. gracilis as follows: chaetiform sensilla (CS), trichoid sensilla (TS) and basiconic sensilla (BS). Of these, both types of CS and TS can be observed throughout all antennal segments except the terminal 8th article, whereas the BS are observed within the cuticular depressed regions of the articles from the 5th to the 7th segment. According to their relative microstructure and location, the BS arc divided further into three subtypes: large ($BS_1$) small ($BS_2$) and spiniform ($BS_3$). The $BS_1$ can be seen on the 5th article only, while $BS_2$ can be seen on the 5th and 6th articles. The $BS_3$ is characteristically seen within the depressive region of the 7th article. Both the CS and TS of O. gracilis are similar in structure, and they are related to the function of mechanical reception; however, four large apical cones (AP) and three subtypes of BS are likely to function in gustatory and olfactory reception.

• Journal of Veterinary Clinics
• /
• v.36 no.3
• /
• pp.176-179
• /
• 2019

A giant prostatic urethral calculus has not been previously reported in dogs and should be distinguished from prostatic calculus. A 7-year-old castrated male Maltese dog with a 2-month history of relapsing hematuria and urinary incontinence with slowly progressing paraphimosis was referred. On abdominal radiography and ultrasonography, there was a giant calculus in the region of prostate or urethra, one left ureteral calculus, one urinary bladder calculus, and two penile urethral calculi. On computed tomography for evaluating the accurate location and planning the surgical approach, the giant calculus was located at the prostatic urethra. The calculi in urinary bladder, prostatic and penile urethra were surgically removed. These calculi were mixed-type of calcium oxalate monohydrate, struvite and calcium phosphate carbonate. On the basis of the urolith analysis and urine bacterial culture results, antibiotics and prescription diet were adjusted. At the 3-month follow-up, there were no clinical sings but paraphimosis was still remained, and ultrasonography revealed newly-formed, small urethral calculi at the prostatic urethra. This is the first report to describe the case of a canine giant prostatic urethral calculus and its clinical signs, diagnostic imaging findings, treatment, and outcome. CT may be useful to assess the accurate location and surgical approach for such calculi.

• Journal of Veterinary Clinics
• /
• v.32 no.6
• /
• pp.508-510
• /
• 2015

A 7-year-old castrated male Boston terrier dog was referred due to dyspnea and unilateral cervical mass. On physical examination, mass on left submandibular region was palpated. CT findings revealed this case could be the tumor originated from left lingual vein. The client refused further treatment and the patient expired because of respiratory failure 10 days after presentation. On necropsy, a well-defined firm mass which located in the left side of larynx was detected. Histopathological findings for the mass indicated polygonal tumor cells arranged in nest and separated by fibrovascular septa. We performed immunohistochemisry to evaluate of chromogranin A and tumor cells showed positive immunoreactivity for chromogranin A. Based on computed tomography (CT), histopathological and immunohistochemical findings, this case was definitely diagnosed to paraganglioma of the body on the lingual vein. This report describes the clinical findings, CT imaging characteristics, histopathologic and immunohistochemical features of paraganglioma arised from lingual vein in a dog.

• Progress in Medical Physics
• /
• v.23 no.4
• /
• pp.309-316
• /
• 2012

Multimodal-imaging technique has been rapidly developed for improvement of diagnosis and evaluation of therapeutic effects. In despite of integrated hardware, registration accuracy was decreased due to a discrepancy between multimodal image and insufficiency of count in accordance with different acquisition method of each modality. The purpose of this study was to improve the PET image by event data resampling through analysis of data format, noise and statistical properties of small animal PET list data. Inveon PET listmode data was acquired as static data for 10 min after 60 min of 37 MBq/0.1 ml $^{18}F$-FDG injection via tail vein. Listmode data format was consist of packet containing 48 bit in which divided 8 bit header and 40 bit payload space. Realigned sinogram was generated from resampled event data of original listmode by using adjustment of LOR location, simple event magnification and nonparametric bootstrap. Sinogram was reconstructed for imaging using OSEM 2D algorithm with 16 subset and 4 iterations. Prompt coincidence was 13,940,707 count measured from PET data header and 13,936,687 count measured from analysis of list-event data. In simple event magnification of PET data, maximum was improved from 1.336 to 1.743, but noise was also increased. Resampling efficiency of PET data was assessed from de-noised and improved image by shift operation of payload value of sequential packet. Bootstrap resampling technique provides the PET image which noise and statistical properties was improved. List-event data resampling method would be aid to improve registration accuracy and early diagnosis efficiency.

• Progress in Medical Physics
• /
• v.22 no.4
• /
• pp.172-177
• /
• 2011

The purpose of this study was to analyze $^{68}Ga$-BAPEN dynamic PET image in rat myocardium to evaluate potential of this radiotracer as a perfusion imaging agent. Animal PET/CT scan was done in 9 rats during 120 minutes. Especially we synthesized $^{68}Ga$-BAPEN with kit which is simple and low cost method. PET images showed the in vivo dynamic distribution of $^{68}Ga$-BAPEN in the chest region of rats. Initially $^{68}Ga$-BAPEN PET images showed aorta and liver activities and a few minutes later, $^{68}Ga$-BAPEN moved to myocardium. Regions of interest were drawn on myocardium, liver, lung and blood pool. Time-activity curves showed significant uptake of $^{68}Ga$-BAPEN in myocardium. The contrast ratios of myocardial to blood pool, lung and liver at 60 minutes after injection were 1.66, 2.82 and 0.60. To estimate accurate kinetic parameters, 60 minutes after injection was required to PET scan as myocardium image contrast ratios reached to constant values. As a result, $^{68}Ga$-BAPEN would be suitable radiotracer for PET which can applied to diagnosis of myocardial perfusion diseases after further preclinical and clinical investigations.

• Progress in Medical Physics
• /
• v.22 no.1
• /
• pp.42-51
• /
• 2011

Nuclear medicine images (SPECT, PET) were widely used tool for assessment of myocardial viability and perfusion. However it had difficult to define accurate myocardial infarct region. The purpose of this study was to investigate methodological approach for automatic measurement of rat myocardial infarct size using polar map with adaptive threshold. Rat myocardial infarction model was induced by ligation of the left circumflex artery. PET images were obtained after intravenous injection of 37 MBq $^{18}F$-FDG. After 60 min uptake, each animal was scanned for 20 min with ECG gating. PET data were reconstructed using ordered subset expectation maximization (OSEM) 2D. To automatically make the myocardial contour and generate polar map, we used QGS software (Cedars-Sinai Medical Center). The reference infarct size was defined by infarction area percentage of the total left myocardium using TTC staining. We used three threshold methods (predefined threshold, Otsu and Multi Gaussian mixture model; MGMM). Predefined threshold method was commonly used in other studies. We applied threshold value form 10% to 90% in step of 10%. Otsu algorithm calculated threshold with the maximum between class variance. MGMM method estimated the distribution of image intensity using multiple Gaussian mixture models (MGMM2, ${\cdots}$ MGMM5) and calculated adaptive threshold. The infarct size in polar map was calculated as the percentage of lower threshold area in polar map from the total polar map area. The measured infarct size using different threshold methods was evaluated by comparison with reference infarct size. The mean difference between with polar map defect size by predefined thresholds (20%, 30%, and 40%) and reference infarct size were $7.04{\pm}3.44%$, $3.87{\pm}2.09%$ and $2.15{\pm}2.07%$, respectively. Otsu verse reference infarct size was $3.56{\pm}4.16%$. MGMM methods verse reference infarct size was $2.29{\pm}1.94%$. The predefined threshold (30%) showed the smallest mean difference with reference infarct size. However, MGMM was more accurate than predefined threshold in under 10% reference infarct size case (MGMM: 0.006%, predefined threshold: 0.59%). In this study, we was to evaluate myocardial infarct size in polar map using multiple Gaussian mixture model. MGMM method was provide adaptive threshold in each subject and will be a useful for automatic measurement of infarct size.

• Tuberculosis and Respiratory Diseases
• /
• v.67 no.5
• /
• pp.436-444
• /
• 2009

Background: Micro computed tomography (CT) is rapidly developing as an imaging tool, especially for mice, which have become the experimental animal of choice for many pulmonary disease studies. We evaluated the usefulness of micro CT for evaluating lung fibrosis in the murine model of bleomycin-induced lung inflammation and fibrosis. Methods: The control mice (n=10) were treated with saline. The murine model of lung fibrosis (n=60) was established by administering bleomycin intra-tracheally. Among the 70 mice, only 20 mice had successful imaging analyses. We analyzed the micro CT and pathological findings and examined the correlation between imaging scoring in micro CT and histological scoring of pulmonary inflammation or fibrosis. Results: The control group showed normal findings on micro CT. The abnormal findings on micro CT performed at 3 weeks after the administration of bleomycin were ground-glass opacity (GGO) and consolidation. At 6 weeks after bleomycin administration, micro CT showed various patterns such as GGO, consolidation, bronchiectasis, small nodules, and reticular opacity. GGO (r=0.84) and consolidation (r=0.69) on micro CT were significantly correlated with histological scoring that reflected pulmonary inflammation (p<0.05). In addition, bronchiectasis (r=0.63) and reticular opacity (r=0.83) on micro CT shown at 6 weeks after bleomycin administration correlated with histological scoring that reflected lung fibrosis (p<0.05). Conclusion: These results suggest that micro CT findings from a murine model of bleomycin-induced lung fibrosis reflect pathologic findings, and micro CT may be useful for predicting bleomycin-induced lung inflammation and fibrosis in mice.

• The Journal of the Korea Contents Association
• /
• v.15 no.9
• /
• pp.418-424
• /
• 2015

In this study, we proceed if there are any changes in binding ability of receptor-ligand in some degree of SA and in radioactive uptake from the corpus striatum based on small animal experiment in vivo based on the S.A values. By dividing 18F-Fallypride into 3 S.A values(high S.A : 43.29~74 GBq/umol, ordinary S.A : 20.72~29.23 GBq/umol, low S.A : 6.29~8.51 GBq/umol), we injected directly into the veins and performed 90 minutes of dynamic scan using Micro PET. After scanning, we compared and analyzed with Binding Potential (Binding Potential) from the bilateral striatum. high SA and low SA, ordinary SA and low SA showed significant differences. Also, in the image comparison using 18F-Fallypride show high radioactive uptake in the striatum at high SA and ordinary SA, but the radioactive uptake at low SA is lower than other two SA. Since 18F-Fallypride has affinity to dopamine D2/3 pharmacokinetic, the difference of Binding Potentials at decreased level of SA values was not that significant. However, further PET research of the corpus striatum using 18F-Fallypride is necessary because the differences in images and Binding Potentials at 6.5 times smaller SA values compared to high SA value showed were significant.