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Biomedical subjects

Seong Ho Park

Publications and source records attributed to Seong Ho Park.

At least 19 recordsLinked to original sources
PubMed2006

Characterization of benign and malignant solid breast masses: comparison of conventional US and tissue harmonic imaging.

PURPOSE: To prospectively compare the diagnostic performance of radiologists by using conventional ultrasonography (US) and tissue harmonic imaging for the differentiation of benign from malignant solid breast masses, with histologic results used as the reference standard. MATERIALS AND METHODS: The study was approved by the institutional review board, and informed consent was obtained from all patients. Images were obtained with conventional US and tissue harmonic imaging in 88 patients (age range, 25-67 years; mean age, 45 years) with 91 solid breast masses (30 cancers and 61 benign lesions) before excisional or needle biopsy. Three experienced radiologists, who did not perform the examinations, independently analyzed the US findings and provided a level of suspicion to indicate the probability of malignancy. Results were evaluated by using kappa statistics and receiver operating characteristic (ROC) analyses. RESULTS: Regarding the descriptions of US findings, echogenicity (kappa=0.205) was the most discordant between conventional US and tissue harmonic imaging, followed by margin (kappa=0.495), lesion boundary (kappa=0.495), calcifications (kappa=0.537), posterior acoustic transmission (kappa=0.546), echotexture (kappa=0.586), shape (kappa=0.591), and orientation (kappa=0.594). The area under the ROC curve (Az) for conventional US and tissue harmonic imaging was 0.84 and 0.79, respectively, for reader 1; 0.88 and 0.85, respectively, for reader 2; and 0.91 and 0.89, respectively, for reader 3. The overall Az value for the three readers was 0.88 for conventional US and 0.84 for tissue harmonic imaging (95% confidence interval: -0.0950, 0.1646; P=.595). CONCLUSION: The performance of the radiologists with respect to the characterization of solid breast masses as benign or malignant was not significantly improved with tissue harmonic imaging.

Adult↗
PubMed2006

Lymph node metastasis: ultrasmall superparamagnetic iron oxide-enhanced MR imaging versus PET/CT in a rabbit model.

PURPOSE: To prospectively compare the diagnostic accuracy of ultrasmall superparamagnetic iron oxide (USPIO)-enhanced magnetic resonance (MR) imaging and integrated positron emission tomography-computed tomography (PET/CT) for the depiction of lymph node metastasis in an animal model, with histologic findings as the reference standard. MATERIALS AND METHODS: This experiment was approved by the local animal care committee. VX2 carcinoma was implanted into the thighs of 11 rabbits 4 weeks before the imaging study. T2- and T2*-weighted MR examinations were performed 24 hours after USPIO administration, followed by integrated PET/CT. USPIO-enhanced MR imaging and PET/CT analysis for the evaluation of the presence of metastasis in iliac lymph nodes were performed independently by two radiologists and two nuclear medicine physicians, respectively, without histopathologic knowledge. Results were evaluated by using receiver operating characteristic (ROC) analysis, and sensitivities and specificities were compared by using a Z test. RESULTS: Metastases were histopathologically confirmed in 22 of 62 iliac lymph nodes. USPIO-enhanced MR imaging showed a significantly greater area under the ROC curve than did PET/CT (0.984 vs 0.852; P=.023). The respective sensitivity and specificity for the detection of lymph node metastasis were 91% (20 of 22) and 95% (38 of 40) for USPIO-enhanced MR imaging and 64% (14 of 22) and 98% (39 of 40) for PET/CT. In terms of sensitivity, a significant difference was found between USPIO-enhanced MR imaging and PET/CT, particularly for nodal metastasis of less than 5 mm (86% [six of seven] vs 0% [zero of seven]; P=.031), whereas the specificity of the two imaging modalities was similar (P=.226). CONCLUSION: USPIO-enhanced MR imaging results in higher diagnostic accuracy for depicting lymph node metastasis than does PET/CT.

Animals↗
PubMed2006

Percutaneous drainage of postoperative abdominal abscess with limited accessibility: preexisting surgical drains as alternative access route.

PURPOSE: To retrospectively assess the effectiveness and safety of postoperative percutaneous drainage of abdominal abscesses with limited accessibility by using a preexisting surgical drain as an access route. MATERIALS AND METHODS: The study was approved by the institutional review board, and informed consent was not required. The authors reviewed the medical records of 92 patients (62 male, 30 female; median age, 59 years; age range, 3-79 years) with postoperative abdominal abscesses in whom percutaneous drainage was performed by using surgical drains as an access. Factors evaluated included the location and size of the lesion; time between surgery and the drainage procedure; distance between the lesion and surgical drain; presence of fistula; duration of drainage; type of surgical drain; size, type, and length of drainage catheter; and complications. Technical success was defined as adequate placement of a new drainage catheter into the target abscess. Midterm success was defined as avoidance of surgery or additional percutaneous drainage during the 6 months of follow-up. Univariate analysis and multiple logistic regression analysis were performed to determine factors that affected the technical or midterm success of the procedure. RESULTS: Of 92 postoperative abscesses for which the technique was attempted, 56 (61%) had a subphrenic location and 36 (39%) had a peripancreatic location. Technical success was achieved in 87 of the 92 patients (95%). Technical success was not significantly associated with any of the factors tested. Midterm success was achieved in 75 of the 87 patients (86%) in whom technical success was achieved. Midterm failure showed a statistically significant relationship with the presence of fistula (P = .04). No procedure-related complications were identified. CONCLUSION: Percutaneous drainage by using the surgical drain as an access route is an effective and safe alternative for draining postoperative abdominal abscesses that are less accessible with direct puncture..

Abdominal Abscess↗
PubMed2006

Macrovesicular hepatic steatosis in living liver donors: use of CT for quantitative and qualitative assessment.

PURPOSE: To determine prospectively the diagnostic performance of unenhanced computed tomography (CT) in the assessment of macrovesicular steatosis in potential donors for living donor liver transplantation by using same-day biopsy as a reference standard. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained. A total of 154 candidates, including 104 men (mean age, 30.2 years +/- 10.3 [standard deviation]) and 50 women (mean age, 31.8 years +/- 11.2), underwent same-day unenhanced CT and ultrasonography-guided liver biopsy. Histologic degree of macrovesicular steatosis was determined. Three liver attenuation indices were derived: liver-to-spleen attenuation ratio (CT(L)(/S)), difference between hepatic and splenic attenuation (CT(L)(-S)), and blood-free hepatic parenchymal attenuation (CT(LP)). Regression equations were used to quantitatively estimate the degree of macrovesicular steatosis. Limits of agreement between estimated macrovesicular steatosis and the reference standard were calculated. Receiver operating characteristic analyses were used to determine the performance of each index for qualitative diagnosis of macrovesicular steatosis of 30% or greater. The cutoff value that provided a balance between sensitivity and specificity and the highest cutoff value that yielded 100% specificity were determined. RESULTS: Limits of agreement were -14% to 14% for CT(L)(/S) and CT(L)(-S) and -13% to 13% for CT(LP). Performance in diagnosing macrovesicular steatosis of 30% or greater was not significantly different among indices (P > .05). Cutoff values of 0.9, -7, and 58 were determined for CT(L)(/S), CT(L)(-S), and CT(LP), respectively, and provided a balance between sensitivity and specificity. Cutoff values of 0.8, -9, and 42 were determined for CT(L)(/S), CT(L)(-S), and CT(LP), respectively, and yielded 100% specificity for all indices, with corresponding sensitivities of 82%, 82%, and 73% for CT(L)(/S), CT(L)(-S), and CT(LP), respectively. CONCLUSION: Diagnostic performance of unenhanced CT for quantitative assessment of macrovesicular steatosis is not clinically acceptable. Unenhanced CT, however, provides high performance in qualitative diagnosis of macrovesicular steatosis of 30% or greater.

Adult↗
PubMed2006

Nasal bone length at 11-14 weeks of pregnancy in the Korean population.

OBJECTIVES: The aim of this study was to provide reference values for nasal bone length (NBL) scanned at 11-14 weeks' gestation in the Korean population and compare these values with those of the Caucasian and African-American populations. METHODS: From April 2004 to July 2004, fetal NBLs were measured in well-dated, non-anomalous fetuses at 11-14 weeks' gestation in the Korean population. Regression analysis was used to assess the relationship between NBL and crown-rump length (CRL), and reference values including the 5th, 50th, and 95th percentile were calculated for each gestational age. The reference values in our study were compared with those of the Caucasian and African-American populations. RESULTS: A total of 982 cases were prospectively included in the study. NBL increased linearly with advance in CRL and was described by the equation; NBL (mm) = 0.433 + 0.022 x CRL (mm), R(2) = 0.37. The median values (5%, 95%) were 1.5 mm (1.2 mm, 1.9 mm), 1.7 mm (1.4 mm, 2.1 mm), 1.9 mm (1.6 mm, 2.3 mm), and 2.1 mm (1.7 mm, 2.6 mm) for 11, 12, 13, and 14 weeks' gestation, respectively. The median values for each gestational age in the Korean population were significantly lower than those in the Caucasian and African-American populations (P < 0.0001). CONCLUSION: There is a difference in NBL scanned at 11-14 weeks' gestation between the Korean and the Caucasian/African-American populations, and so racial adjustment is needed in the evaluation of the fetal nasal bone for current first-trimester screening.

Black or African American↗
PubMed2006

Effects of irradiation using a radioisotope-filled balloon on tissue hyperplasia caused by stent placement in a canine urethral model.

PURPOSE: To evaluate 20 Gy and 40 Gy of intraluminal beta-irradiation using a 188Re-7mercaptoacetyltriglycine (MAG3)-filled balloon catheter to reduce tissue hyperplasia caused by covered stent placement for 12 weeks of follow-up in a canine urethral model. MATERIAL AND METHODS: Ten dogs underwent 188Re-MAG3-filled balloon dilatation immediately after stent placement; 20 Gy at 1-mm tissue depth in group I (n = 5) and 40 Gy in group II (n = 5), whereas 5 dogs (group III) underwent conventional balloon dilatation only. RESULTS: There were no significant differences among the three groups for percentage diameter of stenosis, although this was highest in group III. There was a tendency toward lower mean thickness of the epithelial layer and the papillary projection for out-stent area, and thickness of the papillary projection and degree of inflammatory cells for instent area in groups I and II compared with group III. Thickness of the papillary projection in out-stent area was significantly different among the three groups (P = 0.031). It was significantly less thick in group I than in group III (P < 0.05), whereas group II was not significantly different from group III. CONCLUSION: 188Re-MAG3-filled balloon dilatation has the potential to reduce tissue hyperplasia after 12 weeks of follow-up in a canine urethral model. The use of 20 Gy compared to 40 Gy did not show significant differences.

Animals↗
PubMed2006

Diagnostic potential of three-dimensional ultrasound-based virtual cystoscopy: an experimental study using pig bladders.

OBJECTIVE: We sought to investigate the feasibility of 3-dimensional ultrasound (3D US)-based virtual cystoscopy in experimentally designed bladder phantoms using pig bladders. MATERIALS AND METHODS: Ten bladder phantoms with simulated polypoid tumors of different sizes were constructed to provide 3D US-based virtual cystoscopic images. The simulated polypoid tumors were divided by their location into 2 groups: group 1 included the polyps on the anterior and posterior walls, and group 2 included those on the remaining 4 walls. Two genitourinary radiologists independently interpreted the virtual cystoscopic images, with a consensus reached for cases with discrepant results. RESULTS: In a consensus reading, 3D US-based virtual cystoscopy detected 44 (91.7%) of 48 polypoid lesions. All lesions (n = 4) with false-negative results were 5 mm or smaller in diameter, and so the detection rate was 81.8% (18/22) for lesions 5 mm or smaller whereas it was 100% (26/26) for lesions larger than 5 mm. The detection rate for group 1 (93.8%) was not significantly different from that for group 2 (90.6%; P = 1.000). There were 7 false-positive lesions. Of these, 5 lesions were seen in group 1, and reverberation artifacts were the most common source of these errors (n = 4). Blind areas were present in 19 (31.7%) of 60 virtual cystoscopic images and were seen only in group 2. The differences in the false-positive rate and the incidence of blind area were statistically significant between both groups (P = 0.036, P = 0.00008, respectively). CONCLUSION: 3D US-based virtual cystoscopy may have diagnostic potential in the detection of polypoid bladder tumors.

Animals↗
PubMed2006

Long-term results and factors affecting patency after removal of nasolacrimal stents.

PURPOSE: To retrospectively evaluate the long-term patency and prognostic factors affecting patency after removal of nasolacrimal stents. MATERIALS AND METHODS: Lacrimal polyurethane stents were removed from 317 lacrimal drainage systems of 275 patients because the stent ceased to function, and immediate and maintained patency were determined with follow-up dacryocystography (DCG) after stent removal. Prognostic factors for patency after stent removal were evaluated by univariate and multivariate analyses for immediate patency and Kaplan-Meier survival analysis and multivariate analysis for maintained patency. RESULTS: All stents were successfully removed under fluoroscopic or endoscopic guidance. After stent removal, 243 lacrimal systems (77%) showed immediate patency. The size of the lacrimal sac was the same (65% of cases), widened (2%), or contracted (33%) after stent removal. The shape of the lacrimal sac was normal in 30% and irregular in 70% of cases after stent removal. Seven-day follow-up DCG was obtained in 169 cases, and maintained patency of the lacrimal system was confirmed on 7-day follow-up DCG in 125 cases. Epiphora recurred in 70 cases (56%) during the mean 8-month follow-up period (range, 1-48 months). The mean maintained patency period after stent removal was 15.7 +/- 2.1 months. The maintained patency rates were 41% at 1 year, 31% at 2 years, and 14% at 4 years after stent removal. Multivariate analysis showed that the size of the lacrimal sac (P < .001) was the only factor affecting immediate and maintained patency after stent removal. CONCLUSIONS: After stent removal in patients with nasolacrimal stent obstruction, the immediate patency rate was 77%; however, the rate of maintained patency decreased progressively with time. The major factor negatively affecting immediate and maintained patency after stent removal was contraction of the lacrimal sac at the time of stent removal.

Adolescent↗
PubMed2006

Flat polyps of the colon: detection with 16-MDCT colonography--preliminary results.

OBJECTIVE: This study evaluates the ability of contrast-enhanced, 16-MDCT colonography to display flat colonic lesions when a very narrow slice thickness (1 mm) is used. CONCLUSION: Less than 50% of flat lesions in our population could be visualized by blinded and unblinded review. Before they could be visualized, flat lesions were 2 mm or greater in height and 7 mm or greater in diameter. Lesions with a height of 1 mm or less were not seen on CT colonography. Contrast enhancement, location on a haustral fold, and abnormal 2D and 3D morphology contributed to lesion conspicuity.

Aged↗
PubMed2006

Contrast-enhanced sonography for prostate cancer detection in patients with indeterminate clinical findings.

OBJECTIVE: The purpose of our study was to evaluate the usefulness of contrast-enhanced sonography for prostate cancer detection in patients with an indeterminate prostate-specific antigen (PSA) level (4-10 ng/mL) and negative findings on digital rectal examination. SUBJECTS AND METHODS: Forty-eight patients underwent gray-scale, color Doppler, and contrast-enhanced sonography examinations and then sonographically guided biopsy. Contrast-enhanced sonography was performed using Levovist at a mechanical index of 1.1-1.4. The performances of the three methods for cancer detection were compared according to biopsy site and patient. RESULTS: Sensitivity by biopsy site was greater on contrast-enhanced sonography (68%) than on gray-scale (39%) and color Doppler (41%) sonography (p > or = 0.05), whereas the specificity and overall accuracy by biopsy site (82% and 77% for gray-scale sonography, 84% and 79% for color Doppler sonography, and 83% and 81% for contrast-enhanced sonography, respectively) were not different for the three methods (p > 0.05). The concordance score for sonography and biopsy results by patient was not different for gray-scale (6.4 +/- 1.8), color Doppler (6.3 +/- 0.6), and contrast-enhanced sonography (6.5 +/- 0.7) (p = 0.281). CONCLUSION: Contrast-enhanced sonography could improve only the sensitivity for cancer detection in analysis by biopsy site but did not improve the overall performance of sonography in patients with an indeterminate PSA level and negative digital rectal examination.

Aged↗
PubMed2006

Bloodborne metastatic tumors to the gastrointestinal tract: CT findings with clinicopathologic correlation.

OBJECTIVE: In this essay, we illustrate the CT features of bloodborne metastases to the gastrointestinal tract from various malignancies with an emphasis on clinicopathologic correlation. CONCLUSION: Familiarity with CT findings of bloodborne metastases to the gastrointestinal tract and an understanding of the disease spread pattern in common primary cancers will be helpful not only in detecting metastatic disease but also in minimizing the possibility of mistaking metastasis for another metachronous malignancy.

Adult↗
PubMed2006

Unusual malignant tumors of the gallbladder.

OBJECTIVE: The purpose of this pictorial essay is to review the spectrum of unusual malignant tumors of the gallbladder and to illustrate their radiologic features. CONCLUSION: Radiologic findings of unusual malignant gallbladder tumors are varied and overlap with those of ordinary gallbladder carcinoma. Despite their rarity, being familiar with the wide spectrum of radiologic findings of these unusual tumors is helpful to improve diagnostic accuracy.

Adult↗
PubMed2006

Hepatic hemangiomas with arterioportal shunt: sonographic appearances with CT and MRI correlation.

OBJECTIVE: The purpose of this study was to summarize and illustrate the sonographic appearance of hepatic hemangiomas with arterioportal shunt and to correlate them with CT and MRI findings. CONCLUSION: High-flow hepatic hemangiomas tend to be seen as hypoechoic lesions at sonography. In the presence of fatty infiltration in the liver, they may accompany peritumoral low-echoic areas presumably caused by peritumoral sparing of fatty infiltration similar to a hyperattenuating or hyperintense peritumoral rim on unenhanced CT or MR chemical shift imaging. Color Doppler sonography may reveal intratumoral flows, large feeding arteries, and reversal of portal flow around the tumor. Knowledge of such sonographic findings may ensure an accurate sonographic diagnosis of these tumors.

Adult↗
PubMed2006

Unusual mesenchymal liver tumors in adults: radiologic-pathologic correlation.

OBJECTIVE: Our purpose was to review a broad spectrum of mesenchymal liver tumors in adults and present their cross-sectional imaging characteristics including radiologic-pathologic correlation. CONCLUSION: Cross-sectional imaging findings of mesenchymal liver tumors in adults are varied and some may overlap with others or even with more common malignant epithelial tumors. However, in some cases, their appearances at cross-sectional imaging studies may reflect characteristic abnormalities that suggest a specific diagnosis. Therefore, familiarity with the radiologic findings of mesenchymal liver tumors and understanding their pathological background is important for increasing the accuracy of radiologic diagnosis.

Adult↗
PubMed2005

False-negative results at multi-detector row CT colonography: multivariate analysis of causes for missed lesions.

PURPOSE: To determine causes of false-negative results at multi-detector row computed tomographic (CT) colonography and determine presumptive causes with logistic regression analysis. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained. The study included 394 colonic segments in 31 men and 25 women at high risk for colorectal cancer (mean age +/- standard deviation, 60.2 years +/- 9.3 for men and 56.8 years +/- 13.3 for women). Multi-detector row CT colonography and colonoscopy (reference standard) were performed in a blinded manner, and the results were compared. CT colonographic findings were interpreted in consensus by two readers using a primary two-dimensional with three-dimensional problem-solving approach. Adequacy of colonic preparation and distention was recorded. Sensitivity and specificity were obtained with 95% confidence intervals (CIs). Lesions missed at CT colonography were retrospectively reassessed to identify why they were missed, and, if the causes were not apparent, logistic regression analysis was performed to determine the presumptive causes. RESULTS: Colonic preparation and distention were optimal in 17 patients (30%) but suboptimal in 37 (66%) and poor enough to make the results nondiagnostic in two (4%). Twenty-nine of 63 lesions were missed at CT colonography. When all flat, sessile, and pedunculated lesions (n = 63) were included, sensitivities were 75% (nine of 12; 95% CI: 48%, 100%) for lesions 10 mm or larger and 79% (19 of 24; 95% CI: 65%, 93%) for those 6 mm or larger. When only sessile and pedunculated lesions (n = 60) were included, corresponding sensitivities were 100% (nine of nine; 73%, 100%) and 90% (19 of 21; 78%, 100%), respectively. All three missed lesions larger than 10 mm were flat, and all three flat lesions were missed. Two 3-mm high lesions, including one invasive adenocarcinoma, were misinterpreted as feces at blinded image review; one 1-mm high tubular adenoma with adenocarcinoma foci could not be visualized even in retrospect. Sessile or pedunculated polyps 5 mm or smaller were significantly more likely to be missed than those 6 mm or larger (adjusted odds ratio, 11.6; P = .027). CONCLUSION: Aside from inadequate bowel preparation and/or distention, flat lesions and small polyps are the two main causes for missed lesions at multi-detector row CT colonography.

Adenocarcinoma↗