• 대한영상의학회지
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• 제82권1호
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• pp.116-127
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• 2021

목적 간 섬유화 단계 평가를 위한 회색조 초음파 영상 기반 텍스처 분석 측정 변수들의 진단적 유용성에 대해 평가한다. 대상과 방법 간 회색조 초음파 검사를 시행한 총 167명의 환자를 대상으로 하였다. 텍스처 분석은 한 명의 의사가 전용 소프트웨어를 이용하여 시행하였으며 3, 5, 6, 7, 8번 간 분절에 20픽셀에 해당하는 원형 관심 영역을 지정하여 측정하였다. 간 섬유화 정도에 대한 표준 품으로는 fibrosis-4 (이하 FIB-4 index)를 사용하였다. 산출된 텍스처 변수들과 간의 섬유화 정도의 비교는 t-검정과 Mann-Whitney U 검정을 사용하였으며, 진단적으로 유의한 변수들에 대하여 수신자 운영 특성 곡선의 곡선 하 면적(area under the receiver operating characteristic curve)으로 진단능을 평가하였다. 결과 연구에 포함된 환자는 정상군(FIB-4 < 1.45, n = 50), 경도(1.45 ≤ FIB-4 ≤ 2.35, n = 37), 중등도(2.35 < FIB-4 ≤ 3.25, n = 27)와 중증 간 섬유화군(FIB-4 > 3.25, n = 53)으로 구분되었다. 간의 5번 분절에서 왜도는 정상군과 경도군 사이에서 통계적으로 유의한 차이를 보였다(각각 0.2392 ± 0.3361, 0.4134 ± 0.3004, p = 0.0109). 정상군과 경도군을 구별하기 위한 왜도의 곡선 하 면적은 0.660 (95% confidence interval, 0.551-0.758) 이었으며, 추정 정확도, 민감도, 특이도는 각각 64%, 87%, 48%로 산출되었다. 결론 왜도는 5번 간 분절에서 정상군과 경도 섬유화군을 구분하는 데 유의한 차이를 보였다.

• Korean Journal of Radiology
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• 제24권6호
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• pp.553-563
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• 2023

Objective: Functional magnetic resonance imaging (fMRI) and diffusion tensor imaging-derived tractography (DTI-t) contribute to the localization of language areas, but their accuracy remains controversial. This study aimed to investigate the diagnostic performance of preoperative fMRI and DTI-t obtained with a simultaneous multi-slice technique using intraoperative direct cortical stimulation (DCS) or corticocortical evoked potential (CCEP) as reference standards. Materials and Methods: This prospective study included 26 patients (23-74 years; male:female, 13:13) with tumors in the vicinity of Broca's area who underwent preoperative fMRI and DTI-t. A site-by-site comparison between preoperative (fMRI and DTI-t) and intraoperative language mapping (DCS or CCEP) was performed for 226 cortical sites to calculate the sensitivity and specificity of fMRI and DTI-t for mapping Broca's areas. For sites with positive signals on fMRI or DTI-t, the true-positive rate (TPR) was calculated based on the concordance and discordance between fMRI and DTI-t. Results: Among 226 cortical sites, DCS was performed in 100 sites and CCEP was performed in 166 sites. The specificities of fMRI and DTI-t ranged from 72.4% (63/87) to 96.8% (122/126), respectively. The sensitivities of fMRI (except for verb generation) and DTI-t were 69.2% (9/13) to 92.3% (12/13) with DCS as the reference standard, and 40.0% (16/40) or lower with CCEP as the reference standard. For sites with preoperative fMRI or DTI-t positivity (n = 82), the TPR was high when fMRI and DTI-t were concordant (81.2% and 100% using DCS and CCEP, respectively, as the reference standards) and low when fMRI and DTI-t were discordant (≤ 24.2%). Conclusion: fMRI and DTI-t are sensitive and specific for mapping Broca's area compared with DCS and specific but insensitive compared with CCEP. A site with a positive signal on both fMRI and DTI-t represents a high probability of being an essential language area.

• Korean Journal of Radiology
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• 제23권9호
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• pp.866-877
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• 2022

Objective: The optimal imaging approach for evaluating pathological nipple discharge remains unclear. We investigated the value of adding ductography to ultrasound (US) for evaluating pathologic nipple discharge in patients with negative mammography findings. Materials and Methods: From July 2003 to December 2018, 101 women (mean age, 46.3 ± 12.2 years; range, 23-75 years) with pathologic nipple discharge were evaluated using pre-ductography (initial) US, ductography, and post-ductography US. The imaging findings were reviewed retrospectively. The standard reference was surgery (70 patients) or > 2 years of follow-up with US (31 patients). The diagnostic performances of initial US, ductography, and post-ductography US for detecting malignancy were compared using the McNemar's test or a generalized estimating equation. Results: In total, 47 papillomas, 30 other benign lesions, seven high-risk lesions, and 17 malignant lesions were identified as underlying causes of pathologic nipple discharge. Only eight of the 17 malignancies were detected on the initial US, while the remaining nine malignancies were detected by ductography. Among the nine malignancies detected by ductography, eight were detected on post-ductography US and could be localized for US-guided intervention. The sensitivities of ductography (94.1% [16/17]) and post-ductography US (94.1% [16/17]) were significantly higher than those of initial US (47.1% [8/17]; p = 0.027 and 0.013, respectively). The negative predictive value of post-ductography US (96.9% [31/32]) was significantly higher than that of the initial US (83.3% [45/54]; p = 0.006). Specificity was significantly higher for initial US than for ductography and post-ductography US (p = 0.001 for all). Conclusion: The combined use of ductography and US has a high sensitivity for detecting malignancy in patients with pathologic nipple discharge and negative mammography. Ductography findings enable lesion localization on second-look post-ductography US, thus facilitating the selection of optimal treatment plans.

• Korean Journal of Radiology
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• 제23권10호
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• pp.1009-1018
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• 2022

Objective: This study aimed to investigate the feasibility of using artificial intelligence (AI) to identify normal chest radiography (CXR) from the worklist of radiologists in a health-screening environment. Materials and Methods: This retrospective simulation study was conducted using the CXRs of 5887 adults (mean age ± standard deviation, 55.4 ± 11.8 years; male, 4329) from three health screening centers in South Korea using a commercial AI (Lunit INSIGHT CXR3, version 3.5.8.8). Three board-certified thoracic radiologists reviewed CXR images for referable thoracic abnormalities and grouped the images into those with visible referable abnormalities (identified as abnormal by at least one reader) and those with clearly visible referable abnormalities (identified as abnormal by at least two readers). With AI-based simulated exclusion of normal CXR images, the percentages of normal images sorted and abnormal images erroneously removed were analyzed. Additionally, in a random subsample of 480 patients, the ability to identify visible referable abnormalities was compared among AI-unassisted reading (i.e., all images read by human readers without AI), AI-assisted reading (i.e., all images read by human readers with AI assistance as concurrent readers), and reading with AI triage (i.e., human reading of only those rendered abnormal by AI). Results: Of 5887 CXR images, 405 (6.9%) and 227 (3.9%) contained visible and clearly visible abnormalities, respectively. With AI-based triage, 42.9% (2354/5482) of normal CXR images were removed at the cost of erroneous removal of 3.5% (14/405) and 1.8% (4/227) of CXR images with visible and clearly visible abnormalities, respectively. In the diagnostic performance study, AI triage removed 41.6% (188/452) of normal images from the worklist without missing visible abnormalities and increased the specificity for some readers without decreasing sensitivity. Conclusion: This study suggests the feasibility of sorting and removing normal CXRs using AI with a tailored cut-off to increase efficiency and reduce the workload of radiologists.

• Korean Journal of Radiology
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• 제23권2호
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• pp.246-255
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• 2022

Objective: To determine the usefulness of Silent MR angiography (MRA) for evaluating intracranial aneurysms treated with stent-assisted coil embolization. Materials and Methods: Ninety-nine patients (101 aneurysms) treated with stent-assisted coil embolization (Neuroform atlas, 71 cases; Enterprise, 17; LVIS Jr, 9; and Solitaire AB, 4 cases) underwent time-of-flight (TOF) MRA and Silent MRA in the same session using a 3T MRI system within 24 hours of embolization. Two radiologists independently interpreted both MRA images retrospectively and rated the image quality using a 5-point Likert scale. The image quality and diagnostic accuracy of the two modalities in the detection of aneurysm occlusion were further compared based on the stent design and the site of aneurysm. Results: The average image quality scores of the Silent MRA and TOF MRA were 4.38 ± 0.83 and 2.78 ± 1.04, respectively (p < 0.001), with an almost perfect interobserver agreement. Silent MRA had a significantly higher image quality score than TOF MRA at the distal internal carotid artery (n = 57, 4.25 ± 0.91 vs. 3.05 ± 1.16, p < 0.001), middle cerebral artery (n = 21, 4.57 ± 0.75 vs. 2.19 ± 0.68, p < 0.001), anterior cerebral artery (n = 13, 4.54 ± 0.66 vs. 2.46 ± 0.66, p < 0.001), and posterior circulation artery (n = 10, 4.50 ± 0.71 vs. 2.90 ± 0.74, p = 0.013). Silent MRA had superior image quality score to TOF MRA in the stented arteries when using Neuroform atlas (4.66 ± 0.53 vs. 3.21 ± 0.84, p < 0.001), Enterprise (3.29 ± 1.59 vs. 1.59 ± 0.51, p = 0.003), LVIS Jr (4.33 ± 1.89 vs. 1.89 ± 0.78, p = 0.033), and Solitaire AB stents (4.00 ± 2.25 vs. 2.25 ± 0.96, p = 0.356). The interpretation of the status of aneurysm occlusion exhibited significantly higher sensitivity with Silent MRA than with TOF MRA when using the Neuroform Atlas stent (96.4% vs. 14.3%, respectively, p < 0.001) and LVIS Jr stent (100% vs. 20%, respectively, p = 0.046). Conclusion: Silent MRA can be useful to evaluate aneurysms treated with stent-assisted coil embolization, regardless of the aneurysm location and type of stent used.

• Korean Journal of Radiology
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• 제24권7호
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• pp.690-697
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• 2023

Objective: ¹⁸F-FP-CIT positron emission tomography (PET) is known for its high sensitivity and specificity for evaluating striatal dopamine transporter (DAT) binding. Recently, for the early diagnose of Parkinson's disease, many researchers focused on the diagnosis of synucleinopathy in organs involved in non-motor symptoms of Parkinson's disease. We investigated the feasibility of salivary gland uptake on ¹⁸F-FP-CIT PET as a new biomarker in patients with parkinsonism. Materials and Methods: A total of 219 participants with confirmed or presumed parkinsonism, including 54 clinically diagnosed idiopathic Parkinson's disease (IPD), 59 suspected and yet undiagnosed, and 106 with secondary parkinsonism, were enrolled. The standardized uptake value ratio (SUVR) of the salivary glands was measured on both early and delayed ¹⁸F-FP-CIT PET scans using the cerebellum as the reference region. Additionally, the delayed-to-early ratio (DE_ratio) of salivary gland was obtained. The results were compared between patients with different PET patterns. Results: The SUVR in early ¹⁸F-FP-CIT PET scan was significantly higher in patients with IPD pattern compared that in the non-dopaminergic degradation group (0.5 ± 0.19 vs. 0.6 ± 0.21, P < 0.001). Compared with the non-dopaminergic degradation group, the DE_ratio was significantly lower in patients with IPD (5.05 ± 1.7 vs. 4.0 ± 1.31, P < 0.001) or atypical parkinsonism patterns (5.05 ± 1.7 vs. 3.76 ± 0.96, P < 0.05). The DE_ratio was moderately and positively correlated with striatal DAT availability in both the whole striatum (r = 0.37, P < 0.001) and posterior putamen (r = 0.36, P < 0.001). Conclusion: Parkinsonism patients with an IPD pattern exhibited a significant increase in uptake on early ¹⁸F-FP-CIT PET and a decrease in the DE_ratio in the salivary gland. Our findings suggest that salivary gland uptake of dual-phase ¹⁸F-FP-CIT PET can provide diagnostic information on DAT availability in patients with Parkinson's disease.

• Korean Journal of Radiology
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• 제24권9호
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• pp.912-923
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• 2023

Objective: This study aimed to validate the risk stratification system (RSS) and biopsy criteria for cervical lymph nodes (LNs) proposed by the Korean Society of Thyroid Radiology (KSThR). Materials and Methods: This retrospective study included a consecutive series of preoperative patients with thyroid cancer who underwent LN biopsy, ultrasound (US), and computed tomography (CT) between December 2006 and June 2015. LNs were categorized as probably benign, indeterminate, or suspicious according to the current US- and CT-based RSS and the size thresholds for cervical LN biopsy as suggested by the KSThR. The diagnostic performance and unnecessary biopsy rates were calculated. Results: A total of 277 LNs (53.1% metastatic) in 228 patients (mean age ± standard deviation, 47.4 years ± 14) were analyzed. In US, the malignancy risks were significantly different among the three categories (all P < 0.001); however, CT-detected probably benign and indeterminate LNs showed similarly low malignancy risks (P = 0.468). The combined US + CT criteria stratified the malignancy risks among the three categories (all P < 0.001) and reduced the proportion of indeterminate LNs (from 20.6% to 14.4%) and the malignancy risk in the indeterminate LNs (from 31.6% to 12.5%) compared with US alone. In all image-based classifications, nodal size did not affect the malignancy risks (short diameter [SD] ≤ 5 mm LNs vs. SD > 5 mm LNs, P ≥ 0.177). The criteria covering only suspicious LNs showed higher specificity and lower unnecessary biopsy rates than the current criteria, while maintaining sensitivity in all imaging modalities. Conclusion: Integrative evaluation of US and CT helps in reducing the proportion of indeterminate LNs and the malignancy risk among them. Nodal size did not affect the malignancy risk of LNs, and the addition of indeterminate LNs to biopsy candidates did not have an advantage in detecting LN metastases in all imaging modalities.

• Korean Journal of Radiology
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• 제23권11호
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• pp.1102-1111
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• 2022

Objective: To evaluate the ultrasonography (US) features for diagnosing metastasis in cervical lymph nodes (LNs) in patients with thyroid cancer and compare the US classification of risk of LN metastasis between European and Korean guidelines. Materials and Methods: From January 2014 to December 2018, US-guided fine-needle aspiration was performed on 836 LNs from 714 patients for the preoperative nodal staging of thyroid cancer. The US features of LNs were retrospectively reviewed for the following features: size, presence of hilum, margin, orientation, cystic change, punctate echogenic foci (PEF), large echogenic foci, eccentric cortical thickening, abnormal vascularity, and cortical hyperechogenicity. A multiple logistic regression analysis was performed to identify the independent US features for the diagnosis of metastatic LNs. The diagnostic performance of independent US features was subsequently evaluated. LNs were categorized according to the Korean Thyroid Imaging Reporting and Data System (K-TIRADS) and European Thyroid Association (ETA) guidelines, and the correlation between the two sets of classifications was assessed. Results: Absence of the hilum, presence of cystic changes, PEF, abnormal vascularity, and cortical hyperechogenicity were independent US features of metastatic LNs. Cystic changes, PEF, abnormal vascularity, and cortical hyperechogenicity showed high specificity (86.8%-99.6%). The absence of the hilum had the highest sensitivity yet low specificity (66.4%). When LNs were classified according to the ETA guidelines and K-TIRADS, they yielded similar categorizations of malignancy risks and were strongly correlated (Spearman coefficient, 0.9766 [95% confidence interval, 0.973-0.979]). According to the ETA guidelines, 9.8% (82/836) of LNs were classified as "not specified." Conclusion: Absence of hilum, cystic changes, PEF, abnormal vascularity, and cortical hyperechogenicity were independent US features suggestive of metastatic LNs in thyroid cancer. Both K-TIRADS and the ETA guidelines provided similar risk stratification for metastatic LNs with a high correlation; however, the ETA guidelines failed to classify 9.8% of LNs into a specific risk stratum. These results may provide a basis for revising LN classification in future guidelines.

• 대한영상의학회지
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• 제85권4호
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• pp.769-779
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• 2024

목적 외상 환자 흉부 CT에서 급성 갈비뼈 골절을 진단하기 위해 개발된 인공지능의 장단점에 대해서 알아보고자 하였다. 대상과 방법 외상으로 응급실에 내원했던 환자들 중 급성 갈비뼈 골절(n = 1159) 또는 정상(n = 50)으로 진단된 1209명의 흉부 CT를 무작위로 선택하였다. 이 중 9명의 급성 갈비뼈 골절 흉부 CT로 인공지능 모델 개발과 훈련을 했으며, 150명의 갈비뼈 골절 흉부 CT와 50명의 정상 흉부 CT로 테스트를 하였고, 나머지 1000명의 급성 갈비뼈 골절 흉부 CT로 내부 검증을 하였다. 급성 갈비뼈 골절에 대한 인공지능 모델의 골절의 유무와 위치에 대한 진단적 정확성과 오류에 대해서 알아보았다. 결과 개발된 인공지능 모델을 테스트 결과 급성 갈비뼈 골절 유무에 대한 민감도, 특이도, 양성예측도, 음성예측도, 정확도는 각각 93.3%, 94%, 97.9%, 82.5%, 95.6%였다. 내부 검증을 했을 때 급성 갈비뼈 골절 유무에 대한 정확도는 96%로 상승되었다. 그러나 급성 갈비뼈 골절 위치의 정확도는 76% (760/1000)로 낮았으며, 그 원인으로는 같은 위치에 있는 견갑골이나 쇄골을 갈비뼈로 잘못 인식(66%) 하거나 일부 갈비뼈를 인식하지 못하는 경우(34%)가 많았다. 결론 급성 갈비뼈 골절 진단을 위한 인공지능 모델이 급성 갈비뼈 골절의 유무 진단에는 높은 정확도를 보였지만 갈비뼈 골절의 정확한 위치를 진단하는 데는 제한점이 있었다.

• Tuberculosis and Respiratory Diseases
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• 제53권4호
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• pp.401-408
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• 2002

목 적 : 투베르쿨린 피부반응 검사는 결핵균 감염을 조사하는 방법으로, 전 세계적으로 널리 사용되고 있다. 그러나 여러 가지 요소에 의해 검사 결과의 판독에 어려움이 따른다. 2000년 미국흉부학회에서는 피검사자의 위험요소를 고려하여 피부반응 검사의 결과를 판단하도록 권장하였다. 우리나라의 경우 높은 결핵 감염율과 BCG 백신 접종률로 인해 피부반응 검사를 통해 현감염, 과거감염, 그리고 비감염을 구별하기 어렵다. 본 연구는 항결핵 약제의 투여를 결정하는데 피부반응 검사가 얼마나 도움이 되는지 알아보기 위해, 피부반응 검사의 음성 예측도를 조사하였다. 방 법 : 2001년 3월 1일부터 7월 31일까지 한림대학교 부속 춘천성심병원의 호흡기 내과에 입원한 환자를 대상으로, 현재 국내에서 사용되고 있는 Tuber culin PPD RT23 2 TU (0.1 ml)를 Mantoux 검사에 따라 시행하였다. 결핵의 진단기준은 1) 세균학적 진단기준으로 객담에서 결핵균이 배양되거나 현미경 검사로 항산균을 증명한 경우 2) 임상적 진단기준으로는 상기 세균학적 검사에서 결핵균을 증명하지 못하였으나, 방사선학적 또는 조직학적으로 결핵에 합당한 소견이나 증상이 있어서 진료의사가 결핵치료를 시행하기로 결정한 경우로 하였다. 결 과 : 등록된 환자 230명중에서 재입원 및 다른 과에 입원 중 전과되거나 중환자실에 입원한 환자 20명 (8.7%)을 제외한 총 210명의 환자를 대상으로 평가하였다. 환자의 평균연령은 $60{\pm}16.8$세였고, 남녀비는 1.28 : 1 (남118명, 여 92병)이였다. 결핵으로 진단된 환자는 53명 (25.2%)이였다. 폐결행이 45명(84.9%)이었고, 세균학적 검사에서 항산균 도말 양성이 22명(배양 양성 13, 배양 음성 9) 이었고, 임상적 진단기준으로 판단한 경우가 23명이었다. 결핵성 늑막염이 8명(15.1%)이었고, 조직학적으포 진단 된 경우가 4명, 임상적으로 판단되어 치료한 경우가 4명이었다. 미국흉부학회의 피부반응 검사의 판단기준에 따라 각각의 환자를 음성 및 양성으로 판정하였을 때, 음성 예측도는 92.3%, 양성 예측도는 47.3%, 민감도와 특이도는 각각 83%, 68.8%이었다. 결 론 : 입원한 호흡기 내과 환자를 대상으로 시행한 투베르쿨린 피부반응 검사는 92.3%의 높은 음성 예측도를 보였으며, 피부반응 검사가 음성으로 판단된 환자에서 항결핵 약제의 투여 여부를 결정하는데 중요한 단서를 제공할 것으로 생각된다.