Yonsei University · Medicine
Professor Jeong-Sik Yu's research lab specializes in diagnostic radiology and medical imaging, with a focus on advanced cross-sectional imaging techniques such as CT and MRI for the evaluation of abdominal and hepatic diseases. The lab investigates vascular abnormalities, including small arterioportal shunts and hemodynamic changes, and contributes to the accurate diagnosis of liver tumors, particularly hepatocellular carcinoma, through dynamic contrast-enhanced imaging and diffusion-weighted imaging. The team also explores the role of multiplanar reconstruction in improving preoperative staging of gastric cancer, emphasizing the integration of advanced imaging protocols for improved clinical decision-making.
Figures are computed from collected data and may differ slightly.
Computed tomography (CT) and ultrasonography (US) are ideally suited for demonstrating urachal remnant diseases. A patent urachus is demonstrated at longitudinal US and occasionally at CT as a tubular connection between the anterosuperior aspect of the bladder and the umbilicus. An umbilical-urachal sinus manifests at US as a thickened tubular structure along the midline below the umbilicus. A vesicourachal diverticulum is usually discovered incidentally at axial CT, appearing as a midline cysti
A small nontumorous arterioportal shunt should be considered one of the causes of focal parenchymal hyperperfusion abnormalities on contrast-enhanced dynamic MR images of the liver in the absence of abnormal signal intensity on static MR images.
Understanding of the hemodynamic changes caused by these small shunts can aid in the interpretation of vascular imaging findings.
Early multiple image acquisition is helpful for the assessment of small hepatocellular carcinoma and is enabled by the high detection rate of contrast enhancement regardless of individual variations in the timing of enhancement.
The addition of DWI has the potential to improve sensitivity, but not the overall diagnostic accuracy, in the assessment of perilesional recurrence of HCCs after chemoembolization.
In evaluating the biliary ductal extension of hilar cholangiocarcinoma, MDCT and MRC showed similar accuracies and agreements.
Dynamic Subtraction MR Imaging of the Liver: Advantages and PitfallsJeong-Sik Yu1 2 and Neil M. Rofsky1Audio Available | Share
In the cirrhotic liver, large size (> or = 15 mm) and T1-weighted hypointensity on in-phase images strongly suggest malignancy of the fat-containing nodules. The presence of numerous nodules < 1 cm suggests that the lesions are benign.
Depending on the lesion size and/or location or the degree of misregistration between the source images, dynamic subtraction MR imaging can be useful for the characterization of hyperintense lesions on precontrast T1-weighted imaging.
In most patients with hepatic cavernous hemangiomas, we found that the speed of contrast enhancement on multiphase dynamic MR imaging enabled us to predict the echo pattern in sonography and vice versa.
The purpose of this study was to compare the relative usefulness of multishot turbo spin echo (TSE) and half-Fourier single-shot turbo spin echo (HASTE) for determination of optimal breath-hold fast T2-weighted technique in terms of lesion detection, lesion-to-liver contrast-to-noise ratio (CNR), and image quality. The images of TSE with and without fat suppression (FS) and of HASTE with and without FS were retrospectively reviewed for 49 patients with 128 lesions. Without FS, TSE and HASTE imag
The degree of circumferential perilesional enhancement of hepatic metastases on arterial phase dynamic MR images would be independent of the lesion size but inversely correlated with the degree of peripheral tumoral vascularity. An understanding of these features may help tumor characterization and should prompt hypotheses and studies of microvascular phenomena in tumoral and epitumoral environments.
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