Biomedical subjects

Jeong-Sik Yu

Publications and source records attributed to Jeong-Sik Yu.

28 records · Page 2Linked to original sources

PubMedDate not supplied

Transient peritumoral enhancement during dynamic MRI of the liver: cavernous hemangioma versus hepatocellular carcinoma.

PURPOSE: The purpose of this work was to compare the incidence and pattern of transient peritumoral parenchymal enhancement for cavernous hemangioma and hepatocellular carcinoma during dynamic MRI of the liver. METHOD: Two hundred seven hemangiomas and 155 hepatocellular carcinomas up to 4 cm in size were retrospectively assessed. The peritumoral enhancement was comparatively analyzed in terms of the shape, extent, signal intensity, and dependence on the size and degree of contrast enhancement of each tumor. RESULTS: For small lesions (<2 cm), hemangiomas (16/141; 11.3%) showed a higher incidence (p = 0.026) of peritumoral enhancement than hepatocellular carcinomas (3/87; 3.5%). For larger lesions (2-4 cm), there was no significant difference (p > 0.05) in the incidence of peritumoral enhancement of hemangiomas (15/66; 22.7%) and hepatocellular carcinomas (15/68; 22.1%). Nineteen (61.3%) of the 31 hemangiomas showed contrast agent filling the entire tumor volume at the phase of peritumoral enhancement. CONCLUSION: In spite of the limited specificity, for a <2 cm small focal lesion with homogeneous contrast enhancement on early phase dynamic MR images in the liver, peritumoral enhancement could suggest a higher possibility of hemangioma rather than hepatocellular carcinoma.

Adult↗

PubMedDate not supplied

Preoperative staging accuracy of multidetector row computed tomography for extrahepatic bile duct carcinoma.

PURPOSE: This study sought to evaluate the accuracy of multidetector computed tomography (MDCT) for preoperative staging of extrahepatic bile duct (EHD) carcinoma and to assess the value of coronal reformations from isotropic voxels. MATERIALS AND METHODS: Thirty patients with surgically proven EHD cancer underwent dynamic MDCT with coronal reformation. Two experienced radiologists independently evaluated contrast-enhanced dynamic transverse CT images (axial approach) and combined transverse and coronal images (combined approach). The radial extent (TNM staging) and the vertical extent of tumors were assessed and correlated with pathological findings of surgical specimen. RESULTS: All of primary tumors were detected by axial and combined CT imaging (100%). Overall accuracy of the T staging was 73% (22/30) with axial and 77% (23/30) with combined CT imaging (P>0.05). The accuracy of N staging was 57% (17/30) with axial and 63% (19/30) with combined CT imaging (P>0.05). The accuracy of M staging was 97% (29/30) with both axial and combined CT imaging. Upper margin accuracy was 97% (29/30) for axial and 100% for combined CT imaging (P>0.05), whereas that of the lower margin was 90% (27/30) for axial and 93% (28/30) for combined CT imaging (P>0.05). CONCLUSIONS: Multidetector computed tomography was sufficiently accurate for evaluating the vertical extents, but radial extents of EHD cancer. The addition of coronal reformatted images did not improve the accuracy for staging of EHD cancer.

Adult↗

PubMedDate not supplied

Diagnostic accuracy of multidetector row computed tomography in T- and N staging of gastric cancer with histopathologic correlation.

PURPOSE: To evaluate the diagnostic accuracy of multidetector row computed tomography (MDCT) for the preoperative T- and N staging of gastric cancer. MATERIALS AND METHODS: Eighty-four consecutive patients with gastric cancer underwent preoperative MDCT. Except for 15 patients who did not undergo surgery, 69 patients were included in our study. Two radiologists independently evaluated the T- and N staging on the axial CT images alone and in combination with the MPR images. For N staging, the new TNM and Japanese classifications were independently used. Differences in staging accuracy for T- and N staging were assessed using the McNemar test. RESULTS: The overall T staging accuracy of the axial and combined axial and MPR images was as follows: 67% (47 of 70 cancers) versus 77% (54 of 70 cancers) (P=0.039). The overall N staging accuracy of the axial and combined axial and MPR images was as follows: 59% (41 of 69 cancers) versus 67% (46 of 69 cancers) (P=0.180, Japanese classification) and 54% (37 of 69 cancers) versus 59% (41 of 69 cancers) (P=0.109, TNM classification). CONCLUSIONS: Using MPR images enables more accurate preoperative T staging of gastric cancer, but not for N staging in either classification system.

Adult↗

PubMedDate not supplied

Dynamic subtraction magnetic resonance imaging of cirrhotic liver: assessment of high signal intensity lesions on nonenhanced T1-weighted images.

PURPOSE: The purpose of this work was to determine the technical feasibility and value of dynamic subtraction (postcontrast-precontrast) magnetic resonance (MR) imaging for the assessment of hyperintense lesions on precontrast T1-weighted images in the cirrhotic liver. METHODS: One hundred four hyperintense lesions on T1-weighted precontrast and arterial phase postcontrast images were subjected to analysis of their subtraction qualities depending on the lesion size, location and/or the degree of misregistration between the source images in 27 different MR imaging sets. RESULTS: The quality of subtraction images was always diagnostic for lesions larger than 2 cm in diameter (n=8) but not diagnostic for 73% (40 of 55 lesions) of small subcentimetric lesions. Thirty-one subcapsular lesions always showed a variable degree of coregistration artifact. Only 3 of 35 lesions with a slice misregistration of 3 mm or more gave rise to subtraction images of diagnostic quality. For determining the contrast enhancement, the area under the receiver operating characteristic curve of 30 verified lesions was significantly larger (P <0.001) for subtraction images than for conventional arterial phase images. CONCLUSION: 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.

Adult↗

PubMedDate not supplied

Unusual cystic neoplasms in the pancreas: radiologic-pathologic correlation.

Cystic neoplasms in the pancreas encompass a broad spectrum of benign, borderline, and malignant lesions that either are primarily cystic or result from the cystic degeneration of solid tumors. Although these lesions show different histologic findings, the overlap of the radiologic findings for many pancreatic cystic lesions makes differentiation difficult, and the clinical manifestations can also overlap. Therefore, some of the pancreatic cystic lesions, especially uncommon lesions, can cause diagnostic confusion, and this may result in unnecessary surgery or inappropriate follow-up. In this article, we discuss and illustrate the radiologic features of unusual cystic neoplasms and the unusual findings of the relatively common cystic neoplasms in the pancreas. We also correlate the radiologic findings with the findings on pathologic analysis.

Humans↗

PubMedDate not supplied

Distinguishing hepatic metastases from hemangiomas: qualitative and quantitative diagnostic performance through dual echo respiratory-triggered fast spin echo magnetic resonance imaging.

OBJECTIVE: To determine the relative value of qualitative (reader opinion) and quantitative (values derived from dual echo T2 fast spin echo [FSE]) measures in distinguishing hepatic metastases from hemangiomas. METHODS: Forty-nine patients with hemangiomas and 23 with metastases were studied with dual echo respiratory-triggered FSE and dynamic 2-dimensional spoiled gradient echo (GRE) imaging. Lesion T2 was estimated from signal intensity ratios on the first and second echoes. Two experienced radiologists independently evaluated groups of images based on 5 separate qualitative measures: first echo FSE, second echo FSE, first and second echo FSE, dynamic GRE, and all images together. RESULTS: The mean calculated T2s were 226 +/- 74 milliseconds for hemangiomas and 105 +/- 22 milliseconds for metastases (P < 0.001). A T2 cutoff of 130 milliseconds distinguished metastases from hemangiomas with a sensitivity of 94%, specificity of 91%, and accuracy of nearly 94%. There was no significant difference between the best quantitative measure and the best qualitative measure for either reader. CONCLUSION: Liver lesion T2 relaxation times calculated from dual echo FSE images provide information useful in discriminating metastases from hemangiomas, as does reader opinion.

Adult↗

PubMedDate not supplied

Eosinophilic hepatic necrosis: magnetic resonance imaging and computed tomography comparison.

OBJECTIVE: To compare the findings of magnetic resonance (MR) imaging with those of computed tomography (CT) of focal liver lesions related to peripheral eosinophilia. METHODS: For 12 patients with peripheral eosinophilia (>7%) examined with hepatic MR imaging and CT, 52 focal hepatic lesions larger than 0.5 cm, including 31 lesions simultaneously found on the 2 imaging modalities, were subjected to a comparative analysis of their imaging features. RESULTS: The total number of lesions distinguished from background liver was 39 (75%) on MR imaging and 44 (85%) on CT scans. On arterial phase images of 10 patients with comparable data, homogeneously hyperintense lesions were demonstrated more frequently (P = 0.006) on MR imaging (16 [50%] of 32 lesions) than on CT scans (4 [13%] of 32 lesions). Only 7 (22%) of the 32 hypoattenuating lesions on portal phase CT were depicted as hypointense lesions on portal phase MR images in 12 patients. On delayed phase images in 8 patients, the number of hyperintense lesions on MR images (9 [56%] of 16) was greater (P = 0.077) than that seen on the CT scans (4 [25%] of 16). CONCLUSIONS: For many focal hepatic lesions related to peripheral eosinophilia, dynamic MR imaging more easily demonstrates lesional enhancement on arterial and delayed phases than CT scans. Because of the higher degree of lesional enhancement of MR imaging compared with CT, the lesion-to-liver contrast may not be sufficient to distinguish the lesion from the background liver, resulting in decreased sensitivity of portal phase dynamic MR imaging.

Adult↗

PubMedDate not supplied

Advanced gastric carcinoma with signet ring cell carcinoma versus non-signet ring cell carcinoma: differentiation with multidetector CT.

OBJECTIVE: The purpose of this study is to assess the capability of multidetector computed tomography (MDCT) to assist in the differentiation of advanced gastric carcinoma with signet ring cell type from that with non-signet ring cell carcinoma (NSRC) with a focus on the thickened stomach wall itself. METHODS: We retrospectively reviewed MDCT results in 80 patients with pathologically proven advanced gastric carcinoma with signet ring cell carcinoma (SRC) (n = 35) and NSRC (n = 45). MDCT images of 80 patients were analyzed retrospectively on gross appearance of thickened gastric wall (polypoid/fungating/ulcerative/diffuse infiltrative), predominantly thickened layer (inner/outer), contrast-enhancement pattern (nonlayered/layered) and degree of enhancement (high/moderate/low). RESULTS: The most common type of gross appearance in both carcinomas was fungating, and the more common contrast-enhancement pattern in both carcinomas was a nonlayered pattern. The predominantly thickened layer was a high attenuation inner layer in both carcinomas. High-degree contrast enhancement was more common in SRC (37.1% of patients) than NSRC (15.6% of patients) with statistically significant difference (P = 0.01). CONCLUSIONS: Multidetector CT cannot distinguish SRC from NSRC based on the thickened stomach wall alone. But, high-degree contrast enhancement was more common in advanced gastric carcinoma with SRC than that with NSRC.

Aged↗

PubMedDate not supplied

Newly developed hepatocellular carcinoma (HCC) in chronic liver disease: MR imaging findings before the diagnosis of HCC.

PURPOSE: The purpose of this work was to describe the initial magnetic resonance (MR) imaging findings obtained before an imaging diagnosis of overt hepatocellular carcinoma (HCC) in the chronically damaged liver. METHODS: One hundred fifty-two newly diagnosed HCCs diagnosed by dynamic computed tomography (n = 111) or by MR imaging (n = 41), in addition to digital subtraction hepatic arteriography, in 96 patients were subjected to analysis of their MR imaging features within the previous 2 years. RESULTS: Ninety-seven (64%) HCC cases showed no focal lesions distinguishable from background hepatic parenchyma in MR images taken before the indication of typical HCC. The remaining 55 (36%) lesions were readily identified in earlier images and were categorized into 3 groups: nonhypervascular lesions (category I, n = 6), lesions with partially hypervascular foci of "nodule-within-nodule" appearance (category II, n = 12), and homogeneously hypervascular and/or T2-weighted hyperintense lesions (category III, n = 37). The size and doubling time of category III lesions (0.7 cm, 154 days) were smaller and shorter than those of the other lesions (1.2 cm, 377 days). CONCLUSIONS: Before the imaging diagnosis of HCCs, the premalignant or early malignant lesions can be found on the prior MR images just in the minority of the lesions in the cirrhotic liver.

Adult↗

PubMedDate not supplied

Transcatheter arterial chemoembolization for hepatocellular carcinoma: anatomic and hemodynamic considerations in the hepatic artery and portal vein.

Hepatocellular carcinoma (HCC) is the most common malignant tumor of the liver. Although several therapeutic options have been advocated, transcatheter arterial chemoembolization (TACE) in particular has been widely performed in the treatment of HCC. Still, hepatic arteriography and portography are mandatory for evaluation of (a) the resectability and multiplicity of HCCs and (b) the hemodynamic status of the portal vein. Thereafter, TACE can be considered as the initial therapeutic modality. The possibility of nontarget organ complications during TACE (eg, ischemic cholecystitis, splenic infarction, gastrointestinal mucosal lesions, pulmonary embolism and infarction, spinal cord injury, ischemic skin lesions) should be taken seriously. A thorough understanding of the anatomic variants and hemodynamic features of the hepatic artery and portal vein is the first step in performing effective and safe TACE for HCC.

Antineoplastic Agents↗