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Biomedical subjects

Seung Hyup Kim

Publications and source records attributed to Seung Hyup Kim.

At least 19 recordsLinked to original sources
PubMed2006

Assessment of cystic renal masses based on Bosniak classification: comparison of CT and contrast-enhanced US.

OBJECTIVES: To compare retrospectively the imaging features of computed tomography (CT) and contrast-enhanced US (CEUS) imaging for the assessment of cystic renal masses using the Bosniak classification system. MATERIALS AND METHODS: The CT and CEUS images of 31 pathologically confirmed cystic renal masses in 31 patients were retrospectively analyzed for septa numbers, wall and/or septa thickness, enhancement degree, and for the presence of a solid component by consensus between two radiologists using the Bosniak classification. Diagnostic accuracies of CT and CEUS for malignant cystic tumor were calculated and compared using McNemar test. RESULTS: Diagnostic accuracies of CT and CEUS for malignant renal tumor were 74% and 90%, respectively, but there were not statistically different (P>0.05). CEUS and CT images showed same Bosniak classification in 23 (74%) lesions and there were differences in 8 (26%) lesions, all of which were upgraded by CEUS; one lesion from I to IV, two lesions from II to IV, two lesions from IIF to III, and three lesions from III to IV. CEUS images depicted more septa in 10 (32%) lesions, more thickened wall and/or septa in 4 (13%) lesions, and stronger enhancement in 19 (61%) lesions. Moreover, for six lesions, solid component was detected by CEUS but not by CT. CONCLUSION: CEUS might better visualize septa number, septa and/or wall thickness, solid component and the enhancement of some renal cystic masses than CT, resulting in upgrade of Bosniak classification and affecting their treatment plan.

Adult↗
PubMed2006

Accuracy of MR imaging for the prediction of myometrial invasion of endometrial carcinoma.

OBJECTIVES: To retrospectively evaluate the accuracy of magnetic resonance (MR) imaging for the prediction of depth of myometrial invasion in the preoperative assessment of women with endometrial carcinoma. METHODS: We retrospectively reviewed the medical records and MR imaging reports of 120 women with pathologically-proven endometrial carcinoma who underwent preoperative pelvic MR imaging between June 1997 and February 2006. Tumor signal intensity, the appearance of the junctional zone (JZ), the presence of large polypoid tumors and leiomyomas were analyzed. Univariate logistic-regression analysis was performed to identify associations between incorrect MR staging and the study variables. RESULTS: Data from 120 patients were registered for the current study and analyzed. The sensitivity, specificity and accuracy of the MR imaging in assessment of myometrial invasion among patients with endometrial carcinoma were: 50.6%, 89.2% and 62.5% respectively. MR differentiation of deep myometrial invasion from superficial disease had an 83.3% accuracy (100 of 120 cases). Isointense JZ to myometrium (P<0.001), and the presence of polypoid tumors (P=0.037) on MR imaging were significantly associated with an underestimation of myometrial invasion by endometrial carcinoma. CONCLUSIONS: Isointense JZ to myometrium and polypoid tumors are difficult to accurately evaluate for myometrial invasion of endometrial carcinoma by MR imaging.

Adult↗
PubMed2006

Hemodynamic investigation of the left renal vein in pediatric varicocele: Doppler US, venography, and pressure measurements.

PURPOSE: To evaluate prospectively the hemodynamic state of the left renal vein with Doppler ultrasonography (US) and venography in pediatric patients with varicocele to assess the "nutcracker phenomenon." MATERIALS AND METHODS: The institutional review board considered this study ethically sound, and parental informed consent was obtained for all subjects. Doppler US of the left renal vein was performed in 27 consecutive boys with varicocele (age range, 7-15 years; mean, 11.9 years) and in 20 boys without varicocele as control subjects (age range, 7-17 years; mean, 11.4 years). Doppler US was used to evaluate left renal vein diameters and peak velocities in the proximal left renal vein near the renal hilum and in the left renal vein between the aorta and superior mesenteric artery (aortomesenteric portion). The diameter ratios and peak velocity ratios between two sites were obtained. For statistical comparison of results, the t test was used. Left renal venography and renocaval pressure measurement were performed in 13 patients with varicocele. The Fisher exact test was used to evaluate the associations between the nutcracker phenomenon (renocaval pressure gradient >/=3 mm Hg) and the development of collateral veins. RESULTS: The diameters of the proximal left renal vein and the peak velocities in the aortomesenteric portion of the left renal vein were significantly different between the varicocele group and the control group (P < .001). The diameter ratios (5.7 +/- 1.8 [standard deviation]) and peak velocity ratios (5.2 +/- 2.6) in patients with varicocele were significantly higher than those in control subjects (3.5 +/- 1.0 and 3.1 +/- 0.8, respectively) (P < .005). According to findings at left renal venography (n = 13), 10 patients (77%) met the criteria for the nutcracker phenomenon. The nutcracker phenomenon was significantly associated with the development of collateral veins (P = .035). CONCLUSION: Doppler US and venography of the left renal vein can show hemodynamic changes of the left renal vein and depict the presence of the nutcracker phenomenon in pediatric varicocele.

Adolescent↗
PubMed2006

Nutcracker syndrome in children with gross haematuria: Doppler sonographic evaluation of the left renal vein.

BACKGROUND: Nutcracker syndrome is characterized by gross haematuria caused by left renal vein (LRV) entrapment. OBJECTIVE: To assess the role of LRV ultrasonography in the diagnosis of the nutcracker syndrome in children. MATERIALS AND METHODS: Twelve children (eight male, four female; mean age 12.8 years) with venographically confirmed nutcracker syndrome (LRV-IVC pressure gradient > or = 3 mm Hg) underwent LRV sonography including Doppler spectral analysis (n=7). The diameter and peak velocity (PV) were measured at two sites of the LRV (renal hilum and aortomesenteric portion). The US findings of nutcracker syndrome were compared with those of 20 control subjects using the t-test. We identified the optimal cut-off value of the US parameters for the diagnosis of the nutcracker syndrome using ROC analysis. RESULTS: The PV at the aortomesenteric portion and the ratio of the PV between the two measured points showed significant differences between the two groups (P<0.0001). The optimum cut-off values were found to be 4.7 for the PV ratio (sensitivity 100%, specificity 90%, accuracy 93%), and 93 cm/s for the PV at the aortomesenteric portion (sensitivity 100%, specificity 85%, accuracy 89%). CONCLUSION: LRV sonography, including Doppler spectral analysis, can demonstrate LRV entrapment haemodynamically.

Adolescent↗
PubMed2006

Scrotal US for evaluation of infertile men with azoospermia.

PURPOSE: To evaluate prospectively the accuracy of scrotal ultrasonography (US) in distinguishing obstructive azoospermia from nonobstructive azoospermia in infertile men by using histologic findings as the reference standard. MATERIALS AND METHODS: The institutional review board approved the study, and informed consent was obtained from each patient. Twenty infertile men (mean age, 34.7 years; 40 testes) with azoospermia were evaluated at scrotal US, with an emphasis on the course of the proximal genital duct: mediastinum testis, epididymal head, epididymal body, and epididymal tail. Testicular volumes were calculated by using the formula: length x height x width x 0.71. On the basis of histologic results, azoospermia was divided into two groups (obstructive vs nonobstructive) in all cases except one. Scrotal US findings between obstructive and nonobstructive azoospermia were compared. The Fisher exact and Wilcoxon signed rank sum tests were used to assess differences between both groups. RESULTS: Of 20 infertile men with azoospermia, 14 were proved to have obstructive azoospermia; the others had nonobstructive azoospermia. According to US findings, epididymal abnormalities in the head, body, and tail were significantly associated with obstructive azoospermia (17 [61%], 18 [64%], and 20 [71%] of 28 testes, respectively; P < .001 for all), while abnormalities of the mediastinum testis between both groups were not significant (P > .05). By taking epididymal abnormalities into account, sensitivity, specificity, and accuracy of scrotal US for differentiation of obstructive from nonobstructive azoospermia were 82.1% (23 of 28 scrota), 100% (12 of 12 scrota), and 87.5% (35 of 40 scrota), respectively. The median testicular volume in obstructive azoospermia was 11.6 mL (range, 7.7-25.8 mL) and that in nonobstructive azoospermia was 8.3 mL (range, 1.2-16.4 mL) (P < .05). CONCLUSION: Evaluation of the epididymis and measurement of testicular volume with scrotal US are important in distinguishing obstructive azoospermia from nonobstructive azoospermia in infertile men.

Adult↗
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

Radiologic findings of peripheral primitive neuroectodermal tumor arising in the retroperitoneum.

OBJECTIVE: The purpose of this article is to present the radiological findings of peripheral primitive neuroectodermal tumors that arise in the retroperitoneum. CONCLUSION: Peripheral primitive neuroectodermal tumors (PNETs) arising in the retroperitoneum tend to be large and aggressive. Although the imaging appearance of peripheral PNETs is nonspecific, these tumors should be considered in the differential diagnosis when one encounters a large retroperitoneal mass with aggressive features.

Adult↗
PubMed2006

Urine attenuation ratio: A new CT indicator of renal artery stenosis.

OBJECTIVE: The purpose of our study was to evaluate the value of a ratio of the attenuation measurements of urine in each kidney (hereafter referred to as the urine CT attenuation ratio) in the detection and lateralization of significant renal artery stenosis (RAS). SUBJECTS AND METHODS: In 33 patients with suspected renovascular hypertension and 43 normotensive patients, 5-mm-thick transverse CT scans of the kidney area were obtained 4 min after helical CT angiography (CTA). The attenuation of urine in each kidney was measured, and its ratio was calculated. All 76 patients underwent intraarterial digital subtraction angiography within 2 days after the CT examination. The results of angiography were correlated with the urine attenuation ratio of both kidneys. RESULTS: Twenty-six patients showed significant RAS: unilaterally in 20 and bilaterally in six patients. Two patients showed moderate stenosis of renal arteries. The other patients with essential hypertension (n = 5) or normal blood pressure (n = 43) showed normal renal arteries. The CT attenuation of urine in each kidney was measured and its ratio calculated in all patients except four patients with unilateral RAS. The urine CT attenuation ratio in 22 patients with significant RAS ranged from 1.11 to 4.76 (mean, 2.07). The two patients with moderate RAS showed ratios of 1.83 and 1.23. The others (n = 48) had a urine CT attenuation ratio that ranged from 1.00 to 1.54 (mean, 1.07). The difference of the ratio between the RAS group and the normal group was statistically significant (p < 0.01). The mean urine CT attenuation ratio was 2.18 in patients with unilateral RAS (n = 16) and 1.75 in patients with bilateral RAS (n = 6). The difference of the ratio between the two groups was not statistically significant (p = 0.16). At a cutoff value of 1.22, the sensitivity, specificity, positive predictive value, and negative predictive value of the urine CT attenuation ratio in the diagnosis of significant RAS were 95%, 96%, 91%, and 98%, respectively. CONCLUSION: The urine CT attenuation ratio is a simple and reliable indicator with which to detect and lateralize significant RAS and is a useful adjunct to helical CTA.

Adult↗
PubMed2006

MRI for pretreatment lymph node staging in uterine cervical cancer.

OBJECTIVE: The purpose of this article is to assess the accuracy of MRI in detecting pelvic and paraaortic lymph node metastasis from uterine cervical cancer using various imaging criteria. CONCLUSION: Although MRI analysis resulted in relatively low sensitivity, size and margin (spiculated or lobulated) were useful criteria for predicting lymph node metastasis from cervical cancer.

Adolescent↗
PubMed2006

Role of transrectal ultrasonography in the prediction of prostate cancer: artificial neural network analysis.

OBJECTIVE: The purpose of this study was to evaluate the diagnostic performance of an artificial neural network (ANN) model with and without transrectal ultrasonographic (TRUS) data. METHODS: Six hundred eighty-four consecutive patients who had undergone TRUS-guided prostate biopsy from May 2003 to January 2005 were enrolled. We constructed 2 ANN models. One (ANN_1) incorporated patient age, digital rectal examination findings, prostate-specific antigen (PSA) level, PSA density, transitional zone volume, and PSA density in the transitional zone as input data, whereas the other (ANN_2) was constructed with the above and TRUS findings as input data. The performances of these 2 ANN models according to PSA levels (group A, 0-4 ng/mL; group B, 4-10 ng/mL; and group C, >10 ng/mL) were evaluated using receiver operating characteristic analysis. RESULTS: Of the 684 patients who underwent prostate biopsy, 214 (31.3%) were confirmed to have prostate cancer; of 137 patients with positive digital rectal examination results, 60 (43.8%) were confirmed to have prostate cancer; and of 131 patients with positive TRUS findings, 93 (71%) were confirmed to have prostate cancer. In groups A, B, and C, the AUCs for ANN_1 were 0.738, 0.753, and 0.774, respectively; the AUCs for ANN_2 were 0.859, 0.797, and 0.894. In all groups, ANN_2 showed better accuracy than ANN_1 (P < .05). CONCLUSIONS: According to receiver operating characteristic analysis, ANN with TRUS findings was found to be more accurate than ANN without. We conclude that TRUS findings should be included as an input data component in ANN models used to diagnose prostate cancer.

Adult↗
PubMed2005

Diffractive ultrasound in the evaluation of solid breast masses: preliminary results.

PURPOSE: We sought to evaluate diffractive ultrasound (US) in the characterization of solid breast masses. MATERIALS AND METHODS: Forty-eight patients with solid breast masses (24 malignant and 24 benign) observed at conventional US underwent targeted diffractive US before needle biopsy or surgery. The process of locating the lesion was performed with knowledge of the mammography and conventional US. On diffractive US, imaging features, including shape, brightness, echotexture, margin, and boundary echo were analyzed and odds ratio (OR) were calculated to show how the risk of malignancy was altered by the presence of a given finding. RESULTS: Of the 48 solid breast masses seen on conventional US, 46 (96%) were seen at diffractive US. Diffractive US features suggestive of malignancy were irregular shape (OR 11.5), sono-opacity (OR 204), spiculated margin (OR 17.0), and absent boundary echo (OR 11.5) or thick rim (OR 5.5), whereas those of benignancy were round shape (OR 0.03), sonotransmission (OR 0.07) or isodensity (OR 0.01), well-defined margin (OR 0.03), and thin capsule (OR 0.03; P < 0.05). CONCLUSION: The finding of a sono-opaque mass on diffractive US was highly sensitive for malignancy. Further improvement of diffractive US equipment is needed to increase image quality and to permit inclusion of the axillary tail and deep portions of the breast.

Adult↗
PubMed2004

Renal Doppler ultrasound examination of ureteral obstruction in rabbits: effects of different sites and degrees of obstruction on renal resistive index.

RATIONALE AND OBJECTIVES: We sought to investigate the usefulness of Doppler resistive index (RI) in the diagnosis and follow-up of obstructive uropathy of different degrees and different sites of obstruction. METHODS: Forty-six rabbits were classified as follows: group I, partial unilateral obstruction of the proximal ureter (n = 16); group II, complete unilateral obstruction of the proximal ureter (n = 17); group III, complete unilateral obstruction of the distal ureter (n = 13). The RI of the obstructed and contralateral kidneys was measured preoperatively and postoperatively 1 hour, 6 hours, 1 day, 3 days, 1 week, 2 weeks, and 4 weeks, respectively. In each group, the RI was analyzed for statistical differences in the preoperative versus postoperative kidneys, and the obstructed versus contralateral kidneys. We also analyzed the statistical differences in RIs of the obstructed kidneys, in interrenal RI differences (DeltaRI: RI of the obstructed kidney - RI of the contralateral kidney), and in RI ratio (RI of the obstructed kidney / RI of the contralateral kidney) between the 3 groups. RESULTS: The RIs in the obstructed versus contralateral kidneys were significantly increased (P < 0.05) postoperatively at 1 hour, 1 day, and 2 weeks in group I; 6 hours and 1 week in group II; and 1 hour, 6 hours, and 3 days in group III. In obstructed kidneys, the RIs in the postoperative versus preoperative kidneys were significantly increased (P < 0.05) from 1 hour to 2 weeks in group I and from 1 hour to 4 weeks in group II. There were no statistically significant differences in mean RI, DeltaRI, and RI ratio between the 3 groups during the preoperative and postoperative period. CONCLUSIONS: Doppler RI can be elevated in hydronephrotic kidney as a result of both partial and complete obstruction of the ureter. There are no RI differences among obstructed kidneys with different degree and different site of ureteral obstruction.

Animals↗
PubMed2003

CT and MRI findings of cystadenofibromas of the ovary.

The aim of this study was to assess imaging findings on CT or MR images of histologically proven ovarian cystadenofibromas. In the period 1995-2001, 32 histologically proven ovarian cystadenofibromas were identified in 28 women. Of the 32 ovarian cystadenofibromas, 16 tumors were purely cystic and the remaining 16 were complex cystic on CT or MR images. Solid components of 16 complex cystic tumors were seen as nodular ( n=8) or trabecular ( n=9) solid areas. One tumor had both nodular and trabecular solid components. Among 16 complex cystic tumors, 14 had thick or irregular septa; thus, half of ovarian cystadenofibromas had morphological imaging features of malignancy on CT or MR images. On histology, solid components in the cystic tumors were correlated with fibrous stromas that occasionally made a false-positive result for malignancy on imaging.

Adolescent↗
PubMed2003

Prostatic calculi do not influence the level of serum prostate specific antigen in men without clinically detectable prostate cancer or prostatitis.

PURPOSE: Prostatic calculi are common but little is known of their effect on serum prostate specific antigen (PSA). We investigated whether prostatic calculi might influence serum PSA in men with clinically undetectable prostatic cancer or prostatitis. MATERIALS AND METHODS: Between November 1999 and November 2001, 581 consecutive patients underwent serum PSA determination and digital rectal examination. Of these patients 486 without detectable prostatic cancer, or a history or symptoms of prostatitis and with other specified exclusion criteria were included in the study. The detection and volume measurement of prostatic calculi, and the measurement of prostate volume were performed by transrectal ultrasonography. RESULTS: Prostatic calculi were detected in 198 of the 486 men (40.7%). Mean patient age, prostate volume and serum PSA were not significantly different in men with and without prostatic calculi. Prostate volume was significantly greater in patients with abnormally elevated serum PSA than in those with normal levels. However, no significant difference was found between the percent of men with prostatic calculi or the volumes of prostatic calculi in the 2 groups. Univariate logistic regression analysis indicated that the presence or volume of prostatic calculi was not a risk factor for elevated PSA. Multivariate analysis showed that age and prostate volume were associated with elevated PSA. CONCLUSIONS: The presence or volume of prostatic calculi had no significant effect on serum PSA. Our results suggest that the influence of prostatic calculi is irrelevant in men with elevated PSA.

Calculi↗
PubMed2003

Renal cyst ablation with n-butyl cyanoacrylate and iodized oil in symptomatic patients with autosomal dominant polycystic kidney disease: preliminary report.

Fifty renal cysts in 14 patients with autosomal dominant polycystic kidney disease (ADPKD) were treated with percutaneous needle aspiration and intracystic injection of a mixture of n-butyl cyanoacrylate and iodized oil in a ratio of 1:2. At follow-up of 1-12 months, symptoms improved in 12 (86%) of 14 patients, and 25 (81%) of 31 cysts decreased more than 50% in diameter. This procedure appears to be feasible and may be an effective modality in ablation of renal cysts in patients with ADPKD.

Adult↗