The Quality of Reconstructed 3D Images in Multidetector-Row Helical CT: Experimental Study Involving Scan Parameters

JiHoonShin,HoKyuLee,ChoongGonChoi,DaeChulSuh,Tae-HwanLim,강위창 대한영상의학회 2002 Korean Journal of Radiology Vol.3 No.1

Objective: To determine which multidetector-row helical CT scanning technique provides the best-quality reconstructed 3D images, and to assess differences in image quality according to the levels of the scanning parameters used. Materials and Methods: Four objects with different surfaces and contours were scanned using multidetector-row helical CT at three detector-row collimations (1.25, 2.50, 5.00 mm), two pitches (3.0, 6.0), and three different degrees of overlap between the reconstructed slices (0%, 25%, 50%). Reconstructed 3D images of the resulting 72 sets of data were produced using volumetric rendering. The 72 images were graded on a scale from 1 (worst) to 5 (best) for each of four rating criteria, giving a mean score for each criterion and an overall mean score. Statistical analysis was used to assess differences in image quality according to scanning parameter levels. Results: The mean score for each rating criterion, and the overall mean score, varied significantly according to the scanning parameter levels used. With regard to detector-row collimation and pitch, all levels of scanning parameters gave rise to significant differences, while in the degree of overlap of reconstructed slices, there were significant differences between overlap of 0% and of 50% in all levels of scanning parameters, and between overlap of 25% and of 50% in overall accuracy and overall mean score. Among the 18 scanning sequences, the highest score (4.94) was achieved with 1.25 mm detector-row collimation, 3.0 pitch, and 50% overlap between reconstructed slices. Conclusion: Comparison of the quality of reconstructed 3D images obtained using multidetector-row helical CT and various scanning techniques indicated that the 1.25 mm, 3.0, 50% scanning sequence was best. Quality improved as detector-row collimation decreased; as pitch was reduced from 6.0 to 3.0; and as overlap between reconstructed slices increased.

Superficial Endobronchial Lung Cancer:Radiologic-Pathologic Correlation

NaeJinHan,Koun-SikSong,KyungHeeLee,JoonBeomSeo,JinSeongLee,Tae-HwanLim,GilHyunKang 대한영상의학회 2002 Korean Journal of Radiology Vol.3 No.4

Objective: To analyze the plain chest radiographic and CT findings of superficial endobronchial lung cancer and to correlate these with the findings of histopathology. Materials and Methods: This study involved 19 consecutive patients with pathologically proven lung cancer confined to the bronchial wall. Chest radiographs and CT scans were reviewed for the presence of parenchymal abnormalities, endobronchial nodules, bronchial obstruction, and bronchial wall thickening and stenosis. The CT and histopathologic findings were compared. Results: Sixteen of the 19 patients had abnormal chest radiographic findings, while in 15 (79%), CT revealed bronchial abnormalities: an endobronchial nodule in seven, bronchial obstruction in five, and bronchial wall thickening and stenosis in three. Histopathologically, the lesions appeared as endobronchial nodules in 11 patients, irregular thickening of the bronchial wall in six, elevated mucosa in one, and carcinoma in situ in one. Conclusion: CT helps detect superficial endobronchial lung cancer in 79% of these patients, though there is some disagreement between the CT findings and the pathologic pattern of bronchial lesions. Although nonspecific, findings of bronchial obstruction or bronchial wall thickening and stenosis should not be overlooked, and if clinically necessary, bronchoscopy should be performed.

Localized 1H-MR Spectroscopy in Moyamoya Disease before and after Revascularization Surgery

SooMeeLim,Hye-YoungChoi,JungSooSuh,JungHeeLee,KeunHoLim,DaeChulSuh,HoKyuLee,Tae-HwanLim,YoungShinRa 대한영상의학회 2003 Korean Journal of Radiology Vol.4 No.2

Objective: To evaluate, using localized proton magnetic resonance spectroscopy (1H-MRS), the cerebral metabolic change apparent after revascularization surgery in patients with moyamoya disease. Materials and Methods: Sixteen children with moyamoya disease and eight age-matched normal controls underwent MR imaging, MR angiography, conventional angiography, and 99mTc- ECD SPECT. Frontal white matter and the basal ganglia of both hemispheres were subjected to localized 1H-MRS, and after revascularization surgery, four patients underwent follow-up 1H-MRS. Results: Decreased NAA/Cr ratios (1.35 0.14 in patients vs. 1.55 0.24 in controls) and Cho/Cr ratios (0.96 0.13 in patients vs. 1.10 0.11 in controls) were observed in frontal white matter. After revascularization surgery, NAA/Cr and Cho/Cr ratios in this region increased. In the basal ganglia, there is no abnormal metabolic ratios. Conclusion: Localized 1H-MRS revealed abnormal metabolic change in both hemispheres of children with moyamoya disease. Because of its non-invasive nature, 1H-MRS is potentially useful for the preoperative evaluation of metabolic abnormalities and their postoperative monitoring.

Liquid-Crystal Display Monitors and Cathode-Ray Tube Monitors: A Comparison of Observer Performance in the Detection of Small Solitary Pulmonary Nodules

Soon-AHwang,JoonBeomSeo,Byeong-KyooChoi,Kyung-HyunDo,SungMinKo,Soo-Hyunlee,JinSeongLee,Jae-WooSong,Koun-SikSong,Tae-HwanLim 대한영상의학회 2003 Korean Journal of Radiology Vol.4 No.3

Objective: To compare observer performance using liquid-crystal display (LCD) and cathode-ray tube (CRT) monitors in the interpretation of soft-copy chest radiographs for the detection of small solitary pulmonary nodules. Materials and Methods: By reviewing our Medical Center's radiologic information system, the eight radiologists participating in this study (three board-certified and five resident) retrospectively collected 40 chest radiographs showing a solitary noncalcified pulmonary nodule approximately 1 cm in diameter, and 40 normal chest radiographs. All were obtained using a storage-phosphor system, and CT scans of the same patients served as the gold standard for the presence of a pulmonary nodule. Digital images were displayed on both high-resolution LCD and CRT monitors. The readers were requested to rank each image using a fivepoint scale (1 = definitely negative, 3 = equivocal or indeterminate, 5 = definitely positive), and the data were interpreted using receiver operating characteristic (ROC) analysis. Results: The mean area under the ROC curve was 0.8901 0.0259 for the LCD session, and 0.8716 0.0266 for the CRT session (p > 0.05). The reading time for the LCD session was not significantly different from that for the CRT session (37.12 and 41.46 minutes, respectively; p = 0.889). Conclusion: For detecting small solitary pulmonary nodules, an LCD monitor and a CRT monitor are comparable.

Impact of Diabetes Control on Subclinical Atherosclerosis: Analysis from Coronary Computed Tomographic Angiography Registry

박경민,이창훈,Seung-Whan Lee,Sung Cheol Yun,Young-Hak Kim,김용균,원기범,안소희,김신재,양동현,Joon-Won Kang,Tae-HwanLim,고은희,이우제,김민선,박중열,김홍규,조재원,이상곤 대한당뇨병학회 2020 Diabetes and Metabolism Journal Vol.44 No.3

Background: There are limited data on the impact of diabetes control on the risk of subclinical coronary atherosclerosis. Methods: We analyzed 6,434 consecutive asymptomatic individuals without previous history of coronary artery disease who underwent coronary computed tomographic angiography (CCTA) (mean age, 53.7±7.6 years and 4,694 men [73.0%]). The degree and extent of subclinical coronary atherosclerosis were assessed by CCTA, and ≥50% diameter stenosis was defined as significant. A cardiac event was defined as a composite of all-cause death, myocardial infarction, unstable angina, or coronary revascularization. Study participants were categorized as normal (n=5,319), controlled diabetes (glycosylated hemoglobin [HbA1c] <7%, n=747), or uncontrolled diabetes (HbA1c ≥7%, n=368), respectively. Results: Compared with normal individuals, there were no statistically significant differences in the risk of for any atherosclerotic plaque (odds ratio [OR], 1.16; 95% confidence interval [CI], 0.98 to 1.38; P=0.086) and significant coronary artery stenosis (OR, 1.08; 95% CI, 0.82 to 1.42; P=0.583) in controlled diabetic individuals. In contrast, uncontrolled diabetic individuals had consistently higher risks of any atherosclerotic plaque (OR, 2.16; 95% CI, 1.70 to 2.75; P<0.001) and significant coronary artery stenosis (OR, 3.34; 95% CI, 2.52 to 4.43; P<0.001) than normal individuals. During a follow-up of median 5.4 years, there was no significant difference in cardiac events between normal and controlled diabetic individuals (P=0.365). However, uncontrolled diabetes was associated with an increased risk of cardiac events compared with normal individuals (P<0.001) and controlled diabetic individuals (P=0.023). Conclusion: Asymptomatic uncontrolled diabetes was associated with significant subclinical coronary atherosclerosis with subsequent high risk for cardiac events.