• Journal of Veterinary Clinics
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• v.37 no.4
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• pp.169-174
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• 2020

The purpose of this study was to establish normal values for the thoracic limb joint reference angles in Shih Tzu dogs and to describe the standardized CT methodology for measuring the joint reference angle of the humerus. Five pairs of thoracic limbs of Shih Tzu dogs were collected for the CT scans in this study. Three blinded observers measured the joint reference angle of the humerus and radius for each dog by using CT scans in the frontal, sagittal, and axial planes. The means (± SDs) for the average of the right and left humeral joint reference angles were as follows: mMPHA, 83.74 ± 3.95°; mLDHA, 85.04 ± 2.57°; mCaPHA, 46.75 ± 2.20°; mCrDHA, 79.47 ± 1.97°; and HTA, 19.16 ± 2.38°. Means (± SD) for the average of right and left of the radial joint reference angles were as follows: aMPRA, 85.04 ± 1.58°; aLDRA, 87.59 ± 1.37°; aCrPRA, 84.60 ± 1.46°; aCdDRA, 84.27 ± 1.79°; and RTA, 20.91 ± 3.00°. The intraclass correlation coefficients (ICCs) of the joint reference angles for the inter- and intraobserver reliability were good to excellent, except those for the mCrHA and HTA were moderate. Our results suggest that the method of measuring joint reference angles of other long bones by using CT can be applied to thoracic limbs and can extract valid values for one specific breed.

• Journal of the Korean Society of Radiology
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• v.81 no.6
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• pp.1334-1347
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• 2020

Coronavirus disease (COVID-19) has threatened public health as a global pandemic. Chest CT and radiography are crucial in managing COVID-19 in addition to reverse transcription-polymerase chain reaction, which is the gold standard for COVID-19 diagnosis. This is a review of the current status of the use of chest CT and radiography in COVID-19 diagnosis and management and anㄷ introduction of early representative studies on the application of artificial intelligence to chest CT and radiography. The authors also share their experiences to provide insights into the future value of artificial intelligence.

• The Korean Journal of Nuclear Medicine
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• v.32 no.2
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• pp.161-167
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• 1998

Purpose: Segmental parenchymal excretion delay on Tc-99m DISIDA scan is caused by intrahepatic bile duct obstruction. However, the diagnostic value for intrahepatic bile duct obstruction is unknown. We conducted this study to assess the positive predictive value of segmental excretion delay for the diagnosis of intrahepatic bile duct obstruction, and additional benefit over other noninvasive radiologic studies. Materials and Methods: The study population consisted of 43 patients (48 scans) who showed segmental parenchymal excretion delay on Tc-99m DISIDA scan. The results of abdominal CT or ultrasonography, which was done within 1 month of Tc-99m DISIDA scan, were compared with scintigraphic findings. Results: The etiology of segmental parenchymal excretion delay was determined by ERC or PTC in 31 scans, and follow-up studies in 13 scans. No causes were identified in 4 scans. The positive predictive value of segmental parenchymal excretion delay for intrahepatic bile ductobstruction was 92% (44/48). On the other hand, 13% (5/38) of CT and 28% (5/18) of ultrasonography were normal. In 18% (7138) of CT and 17% (3/18) of ultrasonography, only intraheipatic bile duct dilatation was noted without any diagnostic findings of intrahepatic bile duct obstruction. Conclusion: Segmental parenchymal excretion delay on Tc-99m DISIDA scan had a high positive predictive value for the diagnosis of intrahepatic bile duct obstruction. Tc-99m DISIDA scan may be useful for the diagnosis of intrahepatic bile duct obstruction, especially in patients with nondiagnostic CT or ultrasonography. The diagnostic usefulness need to be confirmed by further prospective studies.

• Journal of the Korean Society of Radiology
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• v.15 no.4
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• pp.437-444
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• 2021

To evaluate the usefulness of Volume Axial Mode by comparing analyzing the exposure dose of the patients and the quality of each images from CT images obtained from high pitch mode using the local phantom or volume axial mode to determine the usefulness of he volume axial mode in diagnosing the head and cervical disease in adults. High Pitch Mode, Helical Mode, and Volume axial Mode as adult phantom were tested according to 70 kVp, 80 kVp, and 100 kVp tube voltages during an adult frontal CT scans. The equipment used was GE's Revolution (GE Healthcare, Wisconsin USA) model and iMED X-ray Phantom. The exposure dose of phantom was compared using the images obtained from each protocol, and the image quality was compared by calculating SNR and CNR by setting ROI on each image. When examined using Volume Axial Mode, the exposure dose of phantom was measured 17.12% lower than Helical Mode, 5.35% lower than High Pitch Mode, and both SNR and CNR were improved. Volume Axial Mode is a useful test that reduces investigation time without table movement using high speed rotary scanner, and in which exposure dose is reduced and image quality is improved by acquiring images in a short time of 0.28 seconds of phantom than using High Pitch Mode and Helical Mode. In addition, the fast testing time of Volume Axial Mode can be seen as the biggest advantage CT scans of emergency patients or patients with physical discomfort.

• Journal of Trauma and Injury
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• v.22 no.2
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• pp.134-141
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• 2009

Purpose: Patients with traumatic brain injury (TBI) were referred from other hospitals for further management. In addition, patients routinely underwent computed tomography examinations of the head (HCT) in the referral hospitals. The purpose of this study was to evaluate retrospectively the utility of routine HCT scans according to the severity of TBI. Methods: Patients with TBI referred to our hospital between December 2005 and July 2008 were included in this study. We investigated HCT findings, indications for repeat HCT examinations (routine versus a neurological change), and neurosurgical interventions. The head injury severity was divided into three categories according to the Glasgow Coma Scale (GCS) score, including mild, moderate, and severe TBI. The use of neurosurgical interventions between patients who underwent routine HCT scans and patients who underwent HCT scans for a neurological change were compared according to the severity of TBI. Results: A total of 81 patients met the entry criteria for this study. Among these patients, 67%(n=54) of the patients underwent HCT scans on a routine basis, whereas 33%(n=27) of the patients underwent HCT scans for a neurological change. A total of 21 patients showed signs of a worsening condition on the HCT scans. Neurosurgical intervention was required for 23(28.4%) patients. For patients who underwent routine HCT examinations, no patient with mild TBI underwent a neurosurgical intervention. However, one patient with moderate TBI and three(13%) patients with severe TBI underwent neurosurgical interventions. The kappa index, the level of agreement for HCT indications of intervention and referral reasons for intervention, was 0.65 for high hierarchy hospitals and 0.06 for low hierarchy hospitals. Conclusion: Routine serial HCT examinations in the referred hospitals would be useful for patients with severe head injury and for patients from low hierarchy hospitals where no emergency physicians or neurosurgeons are available.

• Journal of the Korean Society of Radiology
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• v.16 no.5
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• pp.619-625
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• 2022

In the field of imaging medicine, computed tomography is one of the most common test methods and one of the most frequently used test methods in hospitals. However, it is accompanied by a very high radiation exposure compared to other test methods. In order to reduce exposure, CT scans should be performed only when absolutely necessary, and even if the tests are performed because they are absolutely necessary, a protocol that serves the purpose of the test and allows the test to be performed in a small dose should be used. In this study, we wanted to learn about the most up-to-date radiation dose usage information used by the region's leading general hospitals and develop a diagnostic reference level (DRL). In the experimental results, the Head CT and Abdomen CT tests showed that DLP was higher than the NRPB (U.K) and Korean DRL. The DLP values used by Chest CT were low for all 3 types of CT devices. The hospital found that efforts to reduce exposure should be made during CT examinations, and in particular, Head CT and Abdomen CT determined that efforts to reduce exposure were necessary.

• Journal of Korean Neurosurgical Society
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• v.30 no.3
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• pp.384-388
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• 2001

A 51-year-old woman presented with sudden severe headache, vomiting, and right hemiparesis at first admission. Computed tomography(CT) scans revealed an hemorrhagic density at left basal ganglia. Preoperative cerebral angiography showed no vascular lesion. Under the diagnosis of hypertensive intracerebral hemorrhage(ICH), total extirpation of hematoma was done. The postoperative neurological condition improved gradually and discharged without any neurological sequelae. Two months later, she revisited with headache, vomiting and progressive right hemiparesis. CT scans at second admission showed an irregular rim enhanced mass with central low density with surrounding edema at the initial bleeding area. Repeated craniotomy was performed and the mass was partially removed. The histopathological diagnosis of the specimen was confirmed as glioblastoma. The authors report a glioblastoma, which occurred at initial ICH site and regarded as a brain abscess with literature review.

• Annals of Clinical Neurophysiology
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• v.22 no.1
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• pp.19-23
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• 2020

Background: Peripheral nerve injury rarely occurs in patients with rhabdomyolysis. Based on our experience and previous reports, we consider prolonged immobilization a risk factor for the development of peripheral neuropathy in rhabdomyolysis patients. Methods: This study analyzed 28 patients with rhabdomyolysis due to prolonged immobilization. We analyzed their demographic and laboratory data, clinical and imaging findings, and outcomes, and compared these factors between patients with and without neuropathy. Results: Seven of the 28 patients had peripheral neuropathy, including sciatic neuropathy or lumbosacral plexopathy. Compared to those without neuropathy, the patients with neuropathy were younger (p = 0.02), had higher peak creatine kinase (CK) levels (p = 0.02), had higher muscle uptake in bone scans (p = 0.03), and more frequently exhibited abnormal muscle findings in computed tomography (CT) (p = 0.004). Conclusions: Patients with prolonged immobilization-induced rhabdomyolysis and neuropathy had higher CK levels, increased uptake on bone scans, and more-frequent abnormal muscles on CT than those without neuropathy. These findings indicate that peripheral neuropathy is more likely to develop in patients with severe muscle injury.

• Archives of Craniofacial Surgery
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• v.15 no.2
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• pp.63-69
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• 2014

Background: A number of studies have reported complication after reduction of nasal bone fractures. Among complicated cases, some showed improvement in shape of the nose with passage of time. Therefore, we examined these changes using computed tomography (CT) images taken over intervals. Methods: CT scans of 50 patients with new nasal bone fractures were reviewed, and the images were compared amongst preoperative, immediately postoperative, and one month scans. Changes in nasal bone shape, were evaluated based on the angle of nasal bone arch between the nasal bone and frontal process of maxilla, overall shape of arch, mal-alignment of fracture segments involving bony irregularity or bony displacement. These evaluations were used to separate postoperative outcomes into 5 groups: excellent, good, fair, poor, and very poor. Results: Immediate postoperative nasal shape was excellent in 10 cases, good in 31 cases, fair in 8 cases, and poor results in a single case. Postoperative shape at one month was excellent in 37 cases, good in 12 cases, fair in a single case. Conclusion: The overall shape of nasal bone after fracture reduction tended to improve with passage of time.

• Journal of the Korean Society of Radiology
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• v.82 no.6
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• pp.1505-1523
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• 2021

Purpose Although chest CT has been discussed as a first-line test for coronavirus disease 2019 (COVID-19), little research has explored the implications of CT exposure in the population. To review chest CT protocols and radiation doses in COVID-19 publications and explore the number needed to diagnose (NND) and the number needed to predict (NNP) if CT is used as a first-line test. Materials and Methods We searched nine highly cited radiology journals to identify studies discussing the CT-based diagnosis of COVID-19 pneumonia. Study-level information on the CT protocol and radiation dose was collected, and the doses were compared with each national diagnostic reference level (DRL). The NND and NNP, which depends on the test positive rate (TPR), were calculated, given a CT sensitivity of 94% (95% confidence interval [CI]: 91%-96%) and specificity of 37% (95% CI: 26%-50%), and applied to the early outbreak in Wuhan, New York, and Italy. Results From 86 studies, the CT protocol and radiation dose were reported in 81 (94.2%) and 17 studies (19.8%), respectively. Low-dose chest CT was used more than twice as often as standard-dose chest CT (39.5% vs.18.6%), while the remaining studies (44.2%) did not provide relevant information. The radiation doses were lower than the national DRLs in 15 of the 17 studies (88.2%) that reported doses. The NND was 3.2 scans (95% CI: 2.2-6.0). The NNPs at TPRs of 50%, 25%, 10%, and 5% were 2.2, 3.6, 8.0, 15.5 scans, respectively. In Wuhan, 35418 (TPR, 58%; 95% CI: 27710-56755) to 44840 (TPR, 38%; 95% CI: 35161-68164) individuals were estimated to have undergone CT examinations to diagnose 17365 patients. During the early surge in New York and Italy, daily NNDs changed up to 5.4 and 10.9 times, respectively, within 10 weeks. Conclusion Low-dose CT protocols were described in less than half of COVID-19 publications, and radiation doses were frequently lacking. The number of populations involved in a first-line diagnostic CT test could vary dynamically according to daily TPR; therefore, caution is required in future planning.