• Korean Journal of Radiology
• /
• 제22권6호
• /
• pp.912-921
• /
• 2021

Objective: To compare the performance of the deep learning-based lesion detection algorithm (DLLD) in detecting liver metastasis with that of radiologists. Materials and Methods: This clinical retrospective study used 4386-slice computed tomography (CT) images and labels from a training cohort (502 patients with colorectal cancer [CRC] from November 2005 to December 2010) to train the DLLD for detecting liver metastasis, and used CT images of a validation cohort (40 patients with 99 liver metastatic lesions and 45 patients without liver metastasis from January 2011 to December 2011) for comparing the performance of the DLLD with that of readers (three abdominal radiologists and three radiology residents). For per-lesion binary classification, the sensitivity and false positives per patient were measured. Results: A total of 85 patients with CRC were included in the validation cohort. In the comparison based on per-lesion binary classification, the sensitivity of DLLD (81.82%, [81/99]) was comparable to that of abdominal radiologists (80.81%, p = 0.80) and radiology residents (79.46%, p = 0.57). However, the false positives per patient with DLLD (1.330) was higher than that of abdominal radiologists (0.357, p < 0.001) and radiology residents (0.667, p < 0.001). Conclusion: DLLD showed a sensitivity comparable to that of radiologists when detecting liver metastasis in patients initially diagnosed with CRC. However, the false positives of DLLD were higher than those of radiologists. Therefore, DLLD could serve as an assistant tool for detecting liver metastasis instead of a standalone diagnostic tool.

• 한국방사선학회논문지
• /
• 제11권3호
• /
• pp.109-115
• /
• 2017

본 연구의 목적은 128 MDCT(Multi-detector computed tomography)의 CareDose 4D 선량감소 효과와 임상적 유용성을 평가하고자 시행되었다. Phantom과 임상 복부 검사 연구라는 두 가지 방법을 통해 128 MDCT CareDose 4D 시스템 적용 전후의 피사체 피폭선량과 영상 평가를 실시하였다. Phantom 연구에서는 CareDose 4D 적용 전후의 두 그룹에 대하여 중앙과 3, 6, 9, 12시의 방향으로 ROI(Region of interest)를 위치시켰고, 임상 연구에서는 간의 각 8구획에 대하여 CareDose 4D 적용 전 후 두 그룹에 대하여 ROI를 위치하여 CT Number, Noise, DLP(Dose length product)선량을 측정하였다. 측정결과 Phantom 및 임상연구에서 CT Number는 적용 전 후 값에 차이가 없었고(p>.05), 선량관련 CTDIvol(CT dose index volume) 측정값 및 유효선량은 CareDose 4D 적용 후가 낮았다 (p<.05). 결론적으로 CareDose 4D를 사용하면 영상의 화질을 저하시키지 않고 최적의 영상정보를 획득하면서 환자 선량이 감소되는 효과를 얻을 수 있다.

• Korean Journal of Radiology
• /
• 제21권6호
• /
• pp.717-725
• /
• 2020

Objective: To assess left ventricular remodeling patterns using cardiac computed tomography (CT) in children with congenital heart disease and correlate these patterns with their clinical course. Materials and Methods: Left ventricular volume and myocardial mass were quantified in 17 children with congenital heart disease who underwent initial and follow-up end-systolic cardiac CT studies with a mean follow-up duration of 8.4 ± 9.7 months. Based on changes in the indexed left ventricular myocardial mass (LVMi) and left ventricular mass-volume ratio (LVMVR), left ventricular remodeling between the two serial cardiac CT examinations was categorized into one of four patterns: pattern 1, increased LVMi and increased LVMVR; pattern 2, decreased LVMi and decreased LVMVR; pattern 3, increased LVMi and decreased LVMVR; and pattern 4, decreased LVMi and increased LVMVR. Left ventricular remodeling patterns were correlated with unfavorable clinical courses. Results: Baseline LVMi and LVMVR were 65.1 ± 37.9 g/m² and 4.0 ± 3.2 g/mL, respectively. LVMi increased in 10 patients and decreased in seven patients. LVMVR increased in seven patients and decreased in 10 patients. Pattern 1 was observed in seven patients, pattern 2 in seven, and pattern 3 in three patients. Unfavorable events were observed in 29% (2/7) of patients with pattern 1 and 67% (2/3) of patients with pattern 3, but no such events occurred in pattern 2 during the follow-up period (4.4 ± 2.7 years). Conclusion: Left ventricular remodeling patterns can be characterized using cardiac CT in children with congenital heart disease and may be used to predict their clinical course.

• 대한영상의학회지
• /
• 제84권3호
• /
• pp.520-535
• /
• 2023

위장관 출혈은 단일 질환이 아니라 광범위한 위장 질환의 증상 및 임상적 발현이다. 임상적 양상에 따라 명백한 출혈, 잠재 출혈, 원인 불명 출혈로 나눌 수 있으며, 출혈 위치에 따라 Treiz 인대를 기준으로 상부 또는 하부 위장관 출혈로 분류할 수 있다. 혈관 질환, 용종, 종양, 크론병, 이소성 췌장 및 이소성 위조직 등 다양한 질환이 위장관 출혈을 일으킬 수 있다. 명백한 출혈을 위한 영상 검사기법은 CT 혈관조영술, 고식적 혈관조영술 및 핵의학적 검사 등이 사용된다. 잠재 위장관 출혈을 평가하기 위한 영상검사로는 CT 소장조영술이 주로 사용되며, 위장관을 적절히 팽창해서 영상을 획득해야 위음성 혹은 위양성을 최소화하여 진단능을 높일 수 있다. CT 소장조영술에서 진단이 확실하지 않은 경우, Meckel scan이 보완적으로 사용될 수 있다. 원인 불명 위장관 출혈에 대한 검사는 임상 양상과 임상의 혹은 영상의학과 의사의 선호도에 따라 다양한 검사가 시행될 수 있으며, 이에 대한 추가적인 연구가 필요하다.

• 대한기관식도과학회지
• /
• 제4권1호
• /
• pp.43-51
• /
• 1998

Background： Three-dementional imaging with spiral CT(3D spiral CT) is a well established imaging modality which has been investigated in various clinical settings. However the 3D spiral CT in upper airway disease is rarely reported and its results are still obscure. Objectives： To access the usefulness of 3D spiral CT imaging in patients with upper airway diseases. Materials and Methods We performed 3D spiral CT in fourteen patients In whom upper airway diseases were clinically suspected. Nine of these patients had upper airway stenosis, two had laryngeal cartilage fracture, and three had laryngo-hypopharyngeal cancer. For evaluation of location and extent of the lesions, we compared the findings of 3D imaging with those of air tracheogram, conventional 2D CT images, endoscopic and operative findings. Results： In case of stenosis, 3D spiral CT provide significant useful information, particularly the site and length of the stenotic segment. But, it was difficult to define the fracture of the laryngeal framework and to detect the cartilagenous invasion by head and neck cancer using the 3D imaging. Conclusion : The 3D spiral CT was an useful adjunctive method to assess some kind of upper airway disease but not in others. So, we should compare the findings of 3D images with those of other diagnostic tools for accurate diagnosis of the upper airway disease.

• Nuclear Engineering and Technology
• /
• 제55권4호
• /
• pp.1342-1349
• /
• 2023

The planning accuracy of charged particle therapy (CPT) is subject to the accuracy of stopping power (SP) estimation. In this study, we propose a method of deriving a pseudo-triple-energy CT (pTECT) that can be achievable in the existing dual-energy CT (DECT) systems for better SP estimation. In order to remove the direct effect of errors in CT values, relative CT values according to three scanning voltage settings were used. CT values of each tissue substitute phantom were measured to show the non-linearity of the values thereby suggesting the absolute difference and ratio of CT values as parameters for SP estimation. Electron density, effective atomic number (EAN), mean excitation energy and SP were calculated based on these parameters. Two of conventional methods were implemented and compared to the proposed pTECT method in terms of residuals, absolute error and root-mean-square-error (RMSE). The proposed method outperformed the comparison methods in every evaluation metrics. Especially, the estimation error for EAN and mean excitation using pTECT were converging to zero. In this proof-of-concept study, we showed the feasibility of using three CT values for accurate SP estimation. Our suggested pTECT method indicates potential clinical utility of spectral CT imaging for CPT planning.

• Clinical Endoscopy
• /
• 제51권6호
• /
• pp.591-595
• /
• 2018

Intussusception after colonoscopy is an unusual complication. A MEDLINE search revealed only 7 reported cases. We present a report of a 28-year-old man who developed abdominal pain several hours after routine colonoscopy and in whom computed tomography (CT) revealed colocolic intussusception. We postulate that this condition is iatrogenic and induced by suctioning of gas on withdrawal of the colonoscope. A common observation among the reported cases was abdominal pain several hours after colonoscopy and right-sided intussusception. All cases had colonoscopy reaching the right side of the colon. Treatment for adult intussusception remains controversial with regard to reduction versus resection, especially given the high association with a pathological cause and malignancy. Among the 8 reported cases, only the current case did not require surgery. A combination of benign colonoscopy, CT, and the clinical picture should provide sufficient information to initially choose a more conservative treatment approach.

• Korean Journal of Radiology
• /
• 제22권3호
• /
• pp.454-463
• /
• 2021

Interstitial lung abnormalities (ILAs) are radiologic abnormalities found incidentally on chest CT that are potentially related to interstitial lung diseases. Several articles have reported that ILAs are associated with increased mortality, and they can show radiologic progression. With the increased recognition of ILAs on CT, the role of radiologists in reporting them is critical. This review aims to discuss the clinical significance and radiologic characteristics of ILAs to facilitate and enhance their management.

• Asian Pacific Journal of Cancer Prevention
• /
• 제15권5호
• /
• pp.2257-2262
• /
• 2014

A series of studies have explored the role of cytosolic serine hydroxymethyltransferase (SHMT1) C1420T polymorphism in cancer risk, but their results were conflicting rather than conclusive. To derive a more precise estimation of the association between C1420T and cancer risk, the present meta-analysis of 28 available studies with 15,121 cases and 18,023 controls was conducted. The results revealed that there was no significant association between the polymorphism and cancer risk overall. In stratified analysis by cancer type (breast cancer, gastrointestinal cancer, leukemia, lymphoma, and others), the results showed that 1420T allele was associated with decreased risk in leukemia (CT vs. CC: OR= 0.825, 95% CI =0.704-0.966; and CT+TT vs. CC: OR= 0.838, 95% CI = 0.722-0.973), but the same results were not present for other cancer types. When subgroup analysis was performed by source of control (population-based [PB] and hospital-based [HB]), a borderline inverse association was observed for the HB subgroup (CT vs. CC: OR= 0.917, 95% CI = 0.857-0.982) but not for the PB subgroup. Stratifying by geographic area (America, Asia and Europe), significant inverse association was only found in Asia subgroup (CT vs. CC: OR= 0.674, 95% CI = 0.522-0.870). In summary, the findings suggest that SHMT1 C1420T polymorphism is not associated with overall cancer development, but might decrease cancer susceptibility of Asians as well as reduce leukemia risk. Large well-designed epidemiological studies will be necessary to validate the risk identified in the current meta-analysis.

• 대한핵의학회지
• /
• 제26권2호
• /
• pp.235-243
• /
• 1992

Patterns of abnormality in regional cerebral perfusion and its relation to clinical severity was evaluated with 32 head injury patients using $^{99m}Tc-HMPAO$ single photon emission tomography (SPECT). The findings were compared with computed tomography (CT) done within 48 hours of each SPECT study. The initial SPECT study was done within 7 days of injury in 16 cases, between 1 week and 2 months in 12, and after over 2 months in 4. Nineteen of the patients underwent followup SPECT and CT after a mean interval of 1 to 2 months. The initial SPECT showed abnormalities in 96% (31/32) of the patients while CT showed abnormal findings in only 81% (26/32). There were a total of 54 supratentorial SPECT lesions in all. Ninity percent (49/54) of these were of regional hypoperfusion, while 5 lesions showed focal hyperperfusion. The lesions were most often localized in the frontal and temporal lobes. Fifty five percent (30/54) were areas not detected as a lesion on CT. Cerebellar diaschisis was observed in 50% (16/32) of the patients. The degree of perfusion abnormality was quantified by the product of differential activity and a size factor. Correlation between the degree of perfusion abnormality and the clinical severity (Glasgow coma scale) failed to show statistical significance (p=0.053). The amount of change in the degree of perfusion abnormality on follow up SPECT was compared to the amount of change in clinical severity. Perfusion abnormality showed a tendancy to improve in most patients, and the degree of improvement showed significant correlation with the amount of clinical improvement (p < 0.01).