Junichiro Shimizu

Gifu University, Gifu-shi, Gifu-ken, Japan

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Publications (19)23.79 Total impact

  • Article: Virtopsy in a red kangaroo with oral osteomyelitis.
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    ABSTRACT: This report describes the use of computed tomography (CT) in a nondomestic species. Postmortem CT was performed on a red kangaroo (Macropus rufus) and a diagnosis of oral osteomyelitis was made. CT examination revealed bony remodeling of the right mandible, an intraosseous lesion of the right temporal bone, muscle necrosis around the right mandible, and the absence of the right, first, upper molar tooth. Cardiac and intrahepatic gas and a distended intestine due to postmortem gas accumulation were also seen. All the lesions identified with CT were also identified by conventional necropsy, except the cardiac and intrahepatic gases. Virtopsy may be a useful procedure for the noninvasive identification of cause of death and as a guide for necropsy in animals.
    Journal of Zoo and Wildlife Medicine 03/2011; 42(1):128-30. · 0.38 Impact Factor
  • Article: Use of contrast-enhanced CT in the diagnosis of abscesses in cattle.
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    ABSTRACT: We report here the non-contrast and contrast-enhanced computed tomography performed in two calves with brain abscess and multiple pulmonary abscesses with pharyngeal abscess, respectively. Contrast-enhanced computed tomography was useful in the diagnosis of these diseases in both calves. The diseases were confirmed by histopathological examination.
    Journal of Veterinary Medical Science 01/2011; 73(1):113-5. · 0.85 Impact Factor
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    Article: The relationship between the size of caudolateral curvilinear osteophyte of the canine femoral neck and the radiographic view.
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    ABSTRACT: Caudolateral curvilinear osteophyte (CCO), an osteophyte at the site of joint capsule attachment on the caudal aspect of the femoral neck, has been advocated as a radiographic criterion for coxofemoral subluxation. The correlation between the presence of CCO on radiographs (radiographic-CCO), the size of the CCO (CCO index) on three-dimensional computed tomographic (CT) images, and hip evaluation using transverse CT images was assessed in 22 Border Collies. CCOs were detected on the radiographs and CT images of 32% and 100% femurs, respectively. The CCO index correlated significantly with radiographic-CCO, but a large CCO index did not necessarily imply that the CCO was visible on radiographs. Hence, radiographic-CCO findings should be used cautiously in hip evaluation of Border Collies.
    Journal of veterinary science (Suwŏn-si, Korea) 03/2010; 11(1):89-91. · 0.89 Impact Factor
  • Article: Computed tomographic evaluation of cerebral ventricular size in clinically normal calves.
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    ABSTRACT: To evaluate lateral ventricular size in clinically normal calves by use of computed tomography and to examine the relationships between ventricular height (Vh), ventricular area (VA), and ventricular volume (VV). 14 Holstein calves. Procedures-14 calves underwent computed tomography of the head with transverse images acquired from the rostral aspect of the frontal lobe continuing caudally to the level of the foramen magnum. Hemispheric height, Vh, VA, and hemispheric area were measured on images obtained at the level of the interventricular foramen. Ventricular volume was calculated by multiplying the sum of VAs measured on each transverse image by the total slice thickness. The left Vh-to-right Vh ratio was calculated to determine the degree of ventricular asymmetry, which was categorized as normal (ie, symmetric) to minimally asymmetric, mildly asymmetric, or severely asymmetric. Mean +/- SD values for Vh and the Vh-to-hemispheric height ratio were 4.96 +/- 1.56 mm and 7.47%, respectively. The mean VA was 114.29 +/- 47.68 mm(2), and the mean VV was 2,443.50 +/- 1,351.50 mm3. Normal to minimally asymmetric ventricles were identified in 13 calves, and mildly asymmetric ventricles were identified in 1 calf. Significant correlations were found between Vh and VA and between Vh and VV. These results establish reference values for ventricular size in clinically normal calves and suggest that Vh measurement may be a simple and useful technique for examining size of the cerebral ventricles in calves.
    American Journal of Veterinary Research 02/2010; 71(2):135-7. · 1.27 Impact Factor
  • Article: Inflammatory reaction in the herniated degenerative disc materials in miniature dachshunds.
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    ABSTRACT: Histological and immunohistochemical studies were conducted using herniated intervertebral disc materials obtained surgically from 39 miniature dachshunds. Infiltration of inflammatory cells, such as macrophages, neutrophils, T or B lymphocytes, and multinucleated giant cells, were identified in intervertebral disc materials in 23 cases. Furthermore, proliferations of connective tissue, including neovascularization, were also observed in 17 cases. These results suggest that spontaneous regression of herniated intervertebral disc material could occur in affected dogs.
    Journal of Veterinary Medical Science 11/2009; 72(1):81-4. · 0.85 Impact Factor
  • Article: Effect of an autogenous free fat graft on hemilaminectomy defects in dogs.
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    ABSTRACT: The purpose of this study was to evaluate the effect of an autogenous free fat graft (FFG) on hemilaminectomy defects. Hemilaminectomy was performed at three levels in three beagles, and each defect was designated as a control site or a site treated with one of two different sizes of FFG. Subsequently, longitudinal computed tomography scanning and histopathological examination were performed. As a result, no postoperative dural adhesion was recognized at the sites where FFGs were placed regardless of the size of the FFG. Moreover, there was no compression of the spinal cord by the FFG. Therefore, it appears that postoperative dural adhesion was controlled by the FFG and that the possibility of FFG migration into the spinal canal is low in hemilaminectomy. In conclusion, placement of an FFG over the defect was considered useful for preventing complications in hemilaminectomy.
    Journal of Veterinary Medical Science 10/2009; 71(10):1291-4. · 0.85 Impact Factor
  • Article: Significance of imaging features of alveolar echinococcosis in studies on nonhuman primates.
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    ABSTRACT: In this study, we report the imaging findings in two Japanese monkeys (Macaca fuscata) diagnosed with alveolar echinococcosis. Both monkeys were treated with albendazole for 10 years, without surgery. Radiography, computed tomography, and contrast-enhanced ultrasonography were performed under general anesthesia. This is the first report on contrast-enhanced ultrasonographic imaging for alveolar echinococcosis wherein perflubutane was used as the contrast medium. The findings of the imaging analyses were similar to those reported for alveolar echinococcosis in humans, such as snowflake sign and worm-eaten sign. In addition, the serology correlated well with the imaging data in these two monkeys. Therefore, we propose that the imaging findings of alveolar echinococcosis in nonhuman primates may be used to accumulate data on this condition in human alveolar echinococcosis.
    The American journal of tropical medicine and hygiene 10/2009; 81(3):540-4. · 2.59 Impact Factor
  • Article: Measurement of canine pancreatic perfusion using dynamic computed tomography: influence of input-output vessels on deconvolution and maximum slope methods.
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    ABSTRACT: We investigated whether the prerequisite of the maximum slope and deconvolution methods are satisfied in pancreatic perfusion CT and whether the measured parameters between these algorithms are correlated. We examined nine beagles injected with iohexol (200 mgI kg(-1)) at 5.0 ml s(-1). The abdominal aorta and splenic and celiac arteries were selected as the input arteries and the splenic vein, the output veins. For the maximum slope method, we determined the arterial contrast volume of each artery by measuring the area under the curve (AUC) and compared the peak enhancement time in the pancreas with the contrast appearance time in the splenic vein. For the deconvolution method, the artery-to-vein collection rate of contrast medium was calculated. We calculated the pancreatic tissue blood flow (TBF), tissue blood volume (TBV), and mean transit time (MTT) using both algorithms and investigated their correlation based on vessel selection. The artery AUC significantly decreased as it neared the pancreas (P<0.01). In all cases, the peak time of the pancreas (11.5±1.6) was shorter than the appearance time (14.1±1.6) in the splenic vein. The splenic artery-vein combination exhibited the highest collection rate (91.1%) and was the only combination that was significantly correlated between TBF, TBV, and MTT in both algorithms. Selection of a vessel nearest to the pancreas is considered as a more appropriate prerequisite. Therefore, vessel selection is important in comparison of the semi-quantitative parameters obtained by different algorithms.
    European journal of radiology 08/2009; 77(1):175-81. · 2.65 Impact Factor
  • Article: Influence of osmolarity of contrast medium and saline flush on computed tomography angiography: comparison of monomeric and dimeric iodinated contrast media with different iodine concentrations at an identical iodine delivery rate.
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    ABSTRACT: To evaluate the influence of osmolarity of iodinated contrast media and saline flush on the contrast effect in thoracic computed tomography angiography (CTA) at an identical iodine delivery rate (IDR). Seven beagles were used in a cross-over experiment. The contrast media used were iohexol 350 mgI/ml (IOH350; osmolarity 844 mmol/kg) and iodixanol 320 mgI/ml (IDX320; osmolarity 290 mmol/kg). Each contrast medium was administered to groups with and without saline flush at 40.0 mgI/kg/s for all experiments. Dynamic CT scanning was performed at the ninth thoracic vertebra level. The peak value, area under the curve (AUC), and time to peak (TTP) were calculated from the time attenuation curves of the pulmonary artery and aorta. There was no significant difference between IOH350 and IDX320 with or without saline flush in the peak values for the pulmonary artery and aorta. AUC was significantly higher in groups with saline flush for both contrast media and arteries (p<0.05) with no significant difference between contrast media. TTP was significantly longer in groups with saline flush than without saline flush for both contrast media and arteries (p<0.05), with no significant difference between contrast media. There were no significant differences in the contrast effects of monomeric IOH350 and dimeric IDX320 in thoracic CTA when used at an identical IDR. Moreover, saline flush prolonged the peak duration at 600 mgI/kg.
    European journal of radiology 06/2009; 76(1):135-9. · 2.65 Impact Factor
  • Article: Liver lobe torsion in a Shih-tzu dog.
    Journal of Small Animal Practice 04/2009; 50(3):157. · 1.00 Impact Factor
  • Article: Quantitative evaluation of hip joint laxity in 22 Border Collies using computed tomography.
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    ABSTRACT: The purpose of this study was to obtain the computed tomography (CT) data for the hip joints of 22 Border Collies. The dorsolateral subluxation (DLS) score, lateral center edge angle (LCEA), dorsal acetabular rim angle (DARA) and center distance (CD) index were measured on the CT images in a weight-bearing position. Radiographic Norberg angle (NA) was also measured. The mean values were 45.7 +/- 10.2% for DLS score, 85.9 degrees +/- 10.3 degrees for LCEA, 18.5 degrees +/- 7.3 degrees for DARA, 0.40 +/- 0.17 for CD index and 102.7 degrees +/- 6.9 degrees for NA. Since the DLS score and LCEA showed strong correlation, combined use of these parameters might improve diagnostic accuracy. We consider CT evaluation in a weight-bearing position to be a useful method for multidirectional evaluation of hips.
    Journal of Veterinary Medical Science 03/2009; 71(2):247-50. · 0.85 Impact Factor
  • Article: Providing an intelligible explanation to pet owners by using three-dimensional CT images: use of clinical imaging for better informed consent.
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    ABSTRACT: The purpose of the study reported here was to discuss the level of intelligibility of three-dimensional computed tomography (3D-CT) images of clinical patients for persons who are lacking veterinary knowledge. 143 undergraduate students were participated in this study. They were entirely unfamiliar with veterinary anatomy. A survey was conducted using the visual analog scale method with a focus on the level of intelligibility of the 3D-CT images compared to that of the two-dimensional CT images or radiographs. As a result, the mean value of the intelligibility of the 3D-CT image was 88.4 +/- 17.8 points out of 100 points. In clinical cases, it is very difficult for pet owners lacking veterinary knowledge to understand the clinical status of their pets even with explanations using illustrations, radiographs, and transverse CT images. It is considered that better informed consent and patient satisfaction will be obtained provided veterinarians make an effort towards intelligible patient education by using 3D-CT images.
    Veterinary Research Communications 12/2008; 33(4):387-93. · 0.82 Impact Factor
  • Article: A comparison between injection speed and iodine delivery rate in contrast-enhanced computed tomography (CT) for normal beagles.
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    ABSTRACT: The purpose of this study was to compare between the injection speed and iodine delivery rate in order to establish a concept for reproducible contrast timing in contrast-enhanced computed tomography (CT) for small animals. Clinically healthy beagle dogs were administered a nonionic iodinate contrast medium at a dose of 800 mgI/kg; they were divided into 3 groups (n=5, crossover method): in one group, the injection speed was fixed at 1.0 ml/sec, and in the second and third groups, the iodine delivery rate was fixed (the injection durations were 30 and 60 sec, respectively). The variation in scatter of the time to aortic and hepatic peak enhancement in the fixed iodine delivery groups was lower than that in the fixed injection speed group. These results suggest that in contrast-enhanced CT for small animals, the contrast medium should be injected at a fixed iodine delivery rate in order to provide reproducible contrast timing.
    Journal of Veterinary Medical Science 11/2008; 70(10):1027-30. · 0.85 Impact Factor
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    Article: Analysis of blood flow in a third ventricular ependymoma and an olfactory bulb meningioma by using perfusion computed tomography.
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    ABSTRACT: Brain perfusion computed tomography (CT) scanning was performed in a mongrel dog and a golden retriever that were diagnosed with third ventricular tumor and olfactory bulb tumor, respectively, by contrast-enhanced CT. The tumors were pathologically diagnosed as ependymoma and meningioma, respectively. Perfusion CT results revealed that the ependymoma in this study had a lower blood flow, higher blood volume, and greater transit time of blood than the adjacent brain tissue. Further, the meningioma in this study had a higher blood flow, higher blood volume, and greater transit time of blood than the adjacent brain tissue. Perfusion CT can potentially be used for the grading of brain tumors and narrowing differential diagnosis, provided the perfusion CT data of animals are accumulated.
    Journal of Veterinary Medical Science 10/2008; 70(9):981-3. · 0.85 Impact Factor
  • Article: Computed tomography (CT) observation of pulmonary emboli caused by long-term administration of ivermectin in dogs experimentally infected with heartworms.
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    ABSTRACT: Some studies have reported the adulticidal effect of long-term ivermectin (IVM) administration on adult heartworms in canines; however, there are no detailed reports on the course of the pulmonary artery embolism caused by the bodies of dead heartworms during the administration period. In this study, the pulmonary embolism caused over time by the dead worms was observed using computed tomography (CT). We subcutaneously inoculated 2 beagles with 100 infective third-stage larvae (L3) of Dirofilaria immitis. The dogs were orally administered a formulation containing 272 microg of IVM and 652 mg of pyrantel pamoate (Panamectin Chewables P272; Meiji Seika, Tokyo, Japan) at monthly intervals, beginning from 10 months after the subcutaneous inoculation. Along with IVM administration, periodic CT examination of the chest was performed. At 15 months after the initiation of IVM administration, the dogs were euthanized, the living heartworms were collected, and histopathological examination was performed. Starting from 1 month after the IVM administration, peripheral dilation of the pulmonary artery (suspected to be pulmonary embolism) and pneumonia were observed in the CT images; however, these findings improved over time. The appearance and disappearance of these lesions were observed in all the lobes during the IVM administration period. During this period, the clinical symptoms of pulmonary embolism were not recognized. After 1 month of IVM administration, chest radiographic examination revealed radiopaque lesions in 1 dog. Only some of the lesions detected by CT could be detected by radiography. Using echocardiography, heartworms were observed in the pulmonary arteries of both dogs from 6 months after subcutaneous inoculation to the end of the study period. Microfilaria disappeared from the peripheral blood at 1 month after IVM administration in 1 dog, and at 7 months in the other dog. The adult heartworm antigen test yielded positive results starting from 6 months after subcutaneous inoculation in 1 dog and after 7 months in the other dog; these results remained positive until the end of the study period. After the initiation of IVM administration, the ALP and CK levels were transiently elevated. The number of surviving adult worms collected at necropsy was 25 in 1 dog and 31 in the other. Histopathological examination revealed that the peripheral pulmonary artery dilation detected by CT was the embolus that resulted from the bodies of the dead heartworms. Moreover, vessel recanalization and inflammation along with lymphocyte infiltration around the vessels was observed. These results revealed that long-term IVM administration has a gradual adulticidal effect on heartworms in canines and embolism. From recovery findings showed pulmonary embolism in the CT image and histopathologic examination, long-term IVM administration can potentially be used for adulticidal treatment in clinical cases where it is difficult to perform surgical extirpation and administer arsenic therapy.
    Veterinary Parasitology 09/2008; 155(3-4):242-8. · 2.58 Impact Factor
  • Article: The difference of contrast effects of myelography in normal dogs: comparison of iohexol (180 mgI/ml), iohexol (240 mgI/ml) and iotrolan (240 mgI/ml).
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    ABSTRACT: The contrast effects of three different contrast media preparations (iohexol 180 mgI/ml, iohexol 240 mgI/ml and iotrolan 240 mgI/ml) in conventional and CT myelography were compared. Three beagle dogs were used and the study employed a cross-over method (total of 9) for each contrast media. The result of CT myelography showed that the contrast effect of iohexol (180 mgI/ml), which had low viscosity, was highest in cranial sites, and the contrast effect of high-viscosity iotrolan (240 mgI/ml) was highest in caudal sites 5 min after injection of the contrast media preparations. This shows that the diffusion of contrast media preparations in the subarachnoid space is influenced by viscosity. The results of conventional myelography also showed that the diffusion of contrast media preparations is influenced by viscosity. Therefore, it is important to identify the location of spinal lesions in veterinary practice, and low viscosity contrast medium preparation with wide spread contrast effects is considered suitable for myelography.
    Journal of Veterinary Medical Science 08/2008; 70(7):659-63. · 0.85 Impact Factor
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    Article: Brain abscess in a Japanese black calf: utility of computed tomography (CT).
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    ABSTRACT: Computed tomography (CT) was used for diagnosis of brain abscess in a 6-month-old, Japanese black calf presented with neurological dysfunction, compulsive circling and vision disturbance. CT images showed asymmetric lateral ventricles, and presence of intra-cranial multiple low absorption lesions surrounded by capsule suggestive of abscess in the right cerebral hemisphere. Postmortem examination revealed marked swelling of right cerebral hemisphere and olfactory bulb. Multilocular large abscess containing creamy pus was found to occupy most area of periventricular and lateral ventricle. Fusobacterium necrophrum was isolated from the abscess contents as the causative agent. These results demonstrate that CT is useful tool for tentative diagnosis of bovine brain abscess.
    Journal of Veterinary Medical Science 08/2008; 70(7):727-30. · 0.85 Impact Factor
  • Article: Imaging diagnosis--porencephaly in a calf.
    Veterinary Radiology &amp Ultrasound 50(3):301-3. · 1.08 Impact Factor
  • Article: Effect of contrast media formulation on computed tomography angiographic contrast enhancement.
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    ABSTRACT: The characteristics of contrast media formulation (mgI/ml, osmolarity, and viscosity) are generally not considered important in computed tomography (CT) angiography in animals. The purpose of this study was to assess the contrast effect in CT angiography as a function of contrast media formulation, with a constant iodine dose. The contrast effects of three contrast media with different iodine concentrations were compared by administering identical iodine dosages (mgI/kg). The contrast effects of the three contrast media differed, and the area under the time-attenuation curve of iohexol 350 mgI/ml, which had the highest iodine concentration, was the lowest. It was hypothesized that the contrast effect of a contrast medium decreases with higher iodine concentration because of the high amount of residual iodine present in the circulatory system from the injection site to the portion immediately before the great vessels. In addition, the influence of osmotic dilution on contrast media with high osmolarity was also considered. In conclusion, the contrast effect varies with different contrast media formulations, even when the same iodine dosage is administered.
    Veterinary Radiology &amp Ultrasound 49(3):233-7. · 1.08 Impact Factor