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1.  Contrast-Induced Nephropathy in Patients Undergoing Intravenous Contrast-Enhanced Computed Tomography in Korea: A Multi-Institutional Study in 101487 Patients 
Korean Journal of Radiology  2014;15(4):456-463.
To evaluate the prevalence of known risk factors for contrast-induced nephropathy (CIN) and their association with the actual occurrence of CIN in patients undergoing intravenous contrast-enhanced computed tomography (CECT) in Korea.
Materials and Methods
Patients who underwent CECT in 2008 were identified in the electronic medical records of 16 tertiary hospitals of Korea. Data on demographics, comorbidities, prescriptions and laboratory test results of patients were collected following a standard data extraction protocol. The baseline renal function was assessed using the estimated glomerular filtration rate (eGFR). We identified the prevalence of risk factors along the eGFR strata and evaluated their influence on the incidence of CIN, defined as a 0.5 mg/dL or 25% increase in serum creatinine after CECT.
Of 432425 CECT examinations in 272136 patients, 140838 examinations in 101487 patients met the eligibility criteria for analysis. The mean age of the participants was 57.9 ± 15.5 years; 25.1% of the patients were older than 70 years. The prevalence of diabetes mellitus was 11.9%, of hypertension 13.7%, of gout 0.55% and of heart failure was 1.7%. Preventive measures were used in 40238 CECT examinations (28.6%). The prevalence of risk factors and use of preventive measures increased as the renal function became worse. A CIN was occurred after 3103 (2.2%) CECT examinations, revealing a significant association with decreased eGFR, diabetes mellitus, and congestive heart failure after adjustment.
Risk factors for CIN are prevalent among the patients undergoing CECT. Preventive measures were seemingly underutilized and a system is needed to improve preventive care.
PMCID: PMC4105808  PMID: 25053905
Contrast-induced nephropathy; Contrast-enhanced computed tomography; Prevalence; Risk factor
2.  A Comparison of the Use of Contrast Media with Different Iodine Concentrations for Multidetector CT of the Kidney 
Korean Journal of Radiology  2011;12(6):714-721.
To determine the optimal iodine concentration of contrast media for kidney multidetector computed tomography (MDCT) by comparing the degree of renal parenchymal enhancement and the severity of the renal streak artifact with contrast media of different iodine concentrations.
Materials and Methods
A 16-row MDCT was performed in 15 sedated rabbits by injection of 2 mL contrast media/kg body weight at a rate of 0.3 mL/sec. Monomeric nonionic contrast media of 250, 300, and 370 mg iodine/mL were injected at 1-week intervals. Mean attenuation values were measured in each renal structure with attenuation differences among the structures. The artifact was evaluated by CT window width/level and three grading methods. The values were compared with iodine concentrations.
The 370 mg iodine/mL concentration showed significantly higher cortical enhancement than 250 mg iodine/mL in all phases (p < 0.05). There was however no significant difference in the degree of enhancement between the 300 mg iodine/mL and 370 mg iodine/mL concentrations in all phases. There is a significant difference in attenuation for the cortex-outer medulla between 250 mg iodine/mL and 300 mg iodine/mL (p < 0.05). The artifact was more severe with a medium of 370 mg iodine/mL than with 250 mg iodine/mL by all grading methods (p < 0.05).
The 300 mg iodine/mL is considered to be the most appropriate iodine concentration in an aspect of the enhancement and artifact on a kidney MDCT scan.
PMCID: PMC3194776  PMID: 22043154
Kidney; CT; Contrast media; Iodine concentration
3.  Effect of Thin Overlapping Reconstruction on the Attenuation of Small (≤ 3 cm) Renal Cysts in the Nephrographic Phase of MDCT: a Phantom Study 
Korean Journal of Radiology  2006;7(4):275-280.
To evaluate the effect of thin overlapping reconstruction on the attenuation of small (≤ 3 cm) renal cysts in the nephrographic phase of multidetector CT (MDCT).
Materials and Methods
We scanned a phantom kidney containing spheres of various sizes (10, 20, and 30 mm) using both 4- and 16-channel MDCT scanners, and reconstructed images with various slice thickness (T, mm) and intervals (I, mm). The attenuation increase (AI) was measured for each sphere in 240-HU diluted solution of contrast material and compared with the attenuation in 35-HU solution.
On the 4-channel MDCT, thin overlapping reconstruction (T/I = 3/1, compared with 5/5) lowered the AI as much as 17 HU in the 10 mm-sphere and 6 HU in the 20 mm-sphere (p < 0.05). Thin slicing alone was also effective; however overlapping alone was not. On the 16-channel MDCT, AI in the 10 mm-sphere was significantly lower than on the 4-channel MDCT with T/I = 5/5 (p < 0.05), however thinner slicing or overlapping did not affect the attenuation significantly in all of the spheres.
The effect of thin overlapping reconstruction on minimizing falsely elevated attenuation in the nephrographic phase was significant only in cysts ≤ 20 mm on the 4-channel MDCT.
PMCID: PMC2667614  PMID: 17143031
Kidney; Cyst; Computed tomography (CT); Pseudoenhancement
4.  MR Imaging Findings of Ovarian Cystadenofibroma and Cystadenocarcinofibroma: Clues for the Differential Diagnosis 
Korean Journal of Radiology  2006;7(3):199-204.
We wanted to assess the MR imaging findings of ovarian cystadenofibroma and cystadenocarcinofibroma, and we wanted to find clues for making the differential diagnosis between them.
Materials and Methods
The MR images of 12 pathologically proven cystadenofibromas and two cystadenocarcinofibromas were reviewed, with a focus on the internal architecture, signal intensity and enhancement.
All the tumors appeared as multilocular cysts, except for a single unilocular cystic mass and a single solid mass. The previously reported characteristic MR findings of cystadenofibroma (a multilocular cystic mass with a T2-dark-signal-intensity solid component containing small cystic locules) were found in only 43% of the tumors (6/14). Diffuse or partial thickening of the cyst wall with T2-dark signal intensity without a definite solid component was as common as the previous reported findings (6/14). Two cystadenocarcinofibromas showed more prominent solid portions with higher T2-signal intensities and stronger enhancement than did the cystadenofibromas.
Diffuse or partial thickening of the cyst wall with dark-signal-intensity in multilocular cystic masses may suggest ovarian cystadenofibroma, and this type of appearance may be as common as the previously reported characteristic appearance. A prominent solid component with a higher T2-signal intensity and strong enhancement are the typical findings of cystadenocarcinofibroma.
PMCID: PMC2667602  PMID: 16969050
Cystadenofibroma; Ovary; Magnetic resonance (MR)
5.  Characterization of Renal Cell Carcinoma Using Agent Detection Imaging: Comparison with Gray-Scale US 
Korean Journal of Radiology  2005;6(3):173-178.
We wanted to compare the imaging features of renal cell carcinoma (RCC) and their diagnostic accuracy on agent detection imaging (ADI) and gray-scale ultrasonography (US).
Materials and Methods
Thirty non-consecutive patients (age range; 32-80 years, mean age; 53.7 years) with 30 RCCs were examined with gray-scale US and with ADI in conjunction with using SH U 508A. We described the imaging features of the renal tumors obtained from ADI according to their enhancement pattern, the intratumoral anechoic areas and the presence of any pseudocapsule. The imaging features and diagnostic accuracy of ADI and gray-scale US were then compared.
On the ADI exam, the RCCs were shown as being heterogeneous in 87% of the cases (26/30), homogeneous in 7% of the cases (2/30), and there was peripheral irregular enhancement in 7% of the cases (2/30). Intratumoral anechoic areas and pseudocapsule were seen in 87% and 77% of the RCCs on the ADI exam, whereas these features were seen in 53% and 17% of the cases on the gray-scale US, respectively. The diagnostic sensitivity, specificity, and accuracy for RCC with ADI were 97%, 93%, and 95%, respectively. However, those for RCC with using gray-scale US were 70%, 86%, and 78%, respectively. There was a significant difference for the diagnostic accuracy of RCC between ADI and gray-scale US (p < 0.05).
Agent detection imaging can help visualize the enhancement pattern of RCC and improve the diagnostic accuracy of this tumor by better displaying the intratumoral anechoic areas and the pseudocapsule than does the gray-scale US.
PMCID: PMC2685041  PMID: 16145293
Contrast media; Ultrasound (US)
6.  Imaging Features of Gray-Scale and Contrast-Enhanced Color Doppler US for the Differentiation of Transient Renal Arterial Ischemia and Arterial Infarction 
Korean Journal of Radiology  2005;6(3):179-184.
To characterize the imaging features on gray-scale and contrast-enhanced color Doppler US images which differentiate renal ischemia from renal infarction.
Materials and Methods
The segmental renal arteries of eight healthy rabbits were surgically ligated. In four of these rabbits, the ligated renal artery was released 60 minutes after arterial occlusion to cause transient ischemia. In the remaining four rabbits, the arterial ligation was retained to cause a permanent infarction. The gray-scale and contrast-enhanced color Doppler US imaging features of the involved renal parenchyma of both ischemia and infarction groups were compared with respect to the presence or absence of parenchymal swelling, echogenicity changes, tissue loss and perfusion defects.
Parenchyma swelling, echogenic changes, tissue loss and perfusion defects were found to be more extensive in the infarction than the ischemia group. The hyperechoic areas reperfused with blood flow recovered normal echogenicity and perfusion, whereas the hyperechoic areas without reperfusion became renal infarcts.
Gray-scale and contrast-enhanced color Doppler US showed that the hyperechoic areas with reperfusion may reverse to normal parenchyma and allow the differentiation of renal ischemia from renal infarction.
PMCID: PMC2685042  PMID: 16145294
Renal ischemia; Renal infarction; Ultrasonography; Contrast media
7.  Ruptured Corpus Luteal Cyst: CT Findings 
Korean Journal of Radiology  2003;4(1):42-45.
To evaluate the CT findings of ruptured corpus luteal cysts.
Materials and Methods
Six patients with a surgically proven ruptured corpus luteal cyst were included in this series. The prospective CT findings were retrospectively analyzed in terms of the size and shape of the cyst, the thickness and enhancement pattern of its wall, the attenuation of its contents, and peritoneal fluid.
The mean diameter of the cysts was 2.8 (range, 1.5-4.8) cm; three were round and three were oval. The mean thickness of the cyst wall was 4.7 (range, 1-10) mm; in all six cases it showed strong enhancement, and in three was discontinuous. In five of six cases, the cystic contents showed high attenuation. Peritoneal fluid was present in all cases, and its attenuation was higher, especially around the uterus and adnexa, than that of urine present in the bladder.
In a woman in whom CT reveals the presence of an ovarian cyst with an enhancing rim and highly attenuated contents, as well as highly attenuated peritoneal fluid, a ruptured corpus luteal cyst should be suspected. Other possible evidence of this is focal interruption of the cyst wall and the presence of peritoneal fluid around the adnexa.
PMCID: PMC2698057  PMID: 12679633
Computed tomography (CT); Cysts; Hemorrhage; Ovary
8.  Unusual Perirenal Location of a Tailgut Cyst 
Korean Journal of Radiology  2002;3(4):267-270.
The authors describe a case in which a tailgut cyst occurred at an unusual location in a 22-year-old woman referred for abdominal discomfort and urinary frequency. The left abdomen contained a palpable mass, found at imaging studies to be a homogeneous, unilocular and cystic, and anterior to the left kidney. After surgical excision, it was shown to be a tailgut cyst.
PMCID: PMC2713851  PMID: 12514346
Retroperitoneal space, CT; Cyst
9.  Sclerotherapy of Peritoneal Inclusion Cysts: Preliminary Results in Seven Patients 
Korean Journal of Radiology  2001;2(3):164-170.
To evaluate the technical feasibility and the clinical effectiveness of sclerotherapy for the treatment of peritoneal inclusion cysts (PICs).
Materials and Methods
Between June 1996 and February 2001, eight PICs in seven female patients aged 28-43 (mean, 36) years were instilled with sclerosant (povidone-iodine in three, ethanol in three, both povidone-iodine and ethanol in one). All seven patients subsequently experienced less abdominal pain. After drainage via an 8.5-Fr pigtail catheter inserted in the PICs (transabdominally in six cases, transvaginally in one), sclerosant equivalent in volume to about one-third that of drained fluid was introduced daily until the drained volume was less than 5ml. Follow-up by means of clinical procedures and ultrasound was performed every three months, at which time the success rate, possible complications and recurrence were determined.
Sclerotherapy was technically successful in all seven patients, though immediately after the procedure, minor complications were noted in three patients (mild pain in two, mild fever in one). During the follow-up of 4-60 (mean, 24.7) months, sclerotherapy proved successful and without long-term complications in all seven patients: lower abdominal pain disappeared and the diameter of the cysts decreased more than 50%, with complete regression in four cases. During the follow-up period there was no recurrence.
Sclerotherapy following catheter insertion is technically feasible and effective for the treatment of PICs.
PMCID: PMC2718115  PMID: 11752988
Pelvis, cysts; Pelvis, interventional procedures; Pelvis, US; Ovary, cysts
10.  Hypoechoic Rim of Chronically Inflamed Prostate, as Seen at TRUS: Histopathologic Findings 
Korean Journal of Radiology  2001;2(3):159-163.
The purpose of this study is to correlate the findings of peripheral hypoechoic rim, seen at transrectal ultrasonography (TRUS) in chronic prostatitis patients, with the histopthologic findings.
Materials and Methods
Seven patients with pathologically proven chronic prostatitis were involved in this study. The conspicuity of the peripheral hypoechoic prostatic rim, seen at TRUS, was prominent and subtle, and to determine its histopathologic nature, the microscopic findings were reviewed.
In five of seven cases (71%), TRUS demonstrated a prominent peripheral hypoechoic rim. Microscopic examination revealed that inflammatory cell infiltration of prostatic glandular tissue was severe in three cases (42.9%), moderate in two (28.6%), and minimal in two (28.6%). In all seven cases, the common histopathologic findings of peripheral hypoechoic rim on TRUS were loose stromal tissues, few prostatic glands, and sparse infiltration by inflammatory cells.
The peripheral hypoechoic rim accompanying prostatic inflammation and revealed by TRUS reflects a sparsity of prostate glandular tissue and is thought to be an area in which inflammatory cell infiltration is minimal.
PMCID: PMC2718114  PMID: 11752987
Prostate; Prostate, diseases; Prostate, US; Prostatitis
11.  Pelvic Fistulas Complicating Pelvic Surgery or Diseases: Spectrum of Imaging Findings 
Korean Journal of Radiology  2001;2(2):97-104.
Pelvic fistulas may result from obstetric complications, inflammatory bowel disease, pelvic malignancy, pelvic radiation therapy, pelvic surgery, or other traumatic causes, and their symptoms may be distressing. In our experience, various types of pelvic fistulas are identified after pelvic disease or pelvic surgery. Because of its close proximity, the majority of such fistulas occur in the pelvic cavity and include the vesicovaginal, vesicouterine, vesicoenteric, ureterovaginal, ureteroenteric and enterovaginal type. The purpose of this article is to illustrate the spectrum of imaging features of pelvic fistulas.
PMCID: PMC2718108  PMID: 11752977
Fistula, pelvic; Ureteroenteric, enterovaginal; Vesicovaginal, vesicouterine; Vesicoenteric, ureterovaginal
12.  Characteristic Plain Radiographic and Intravenous Urographic Findings of Bladder Calculi Formed over a Hair Nidus: A Case Report 
Korean Journal of Radiology  2001;2(1):61-62.
We present the characteristic plain radiographic and intravenous urographic (IVU) findings of calculus formed over a hair. A 66-year-old man who had been quadriplegic for 40 years because of vertebral injury was admitted for further evaluation of frequent urinary tract infection. Plain radiography showed a linear, serpiginous calcification in the lower abdomen, and IVU revealed a round filling defect with linear radiopacity in the bladder, suggesting calculus. The gross appearance of the stone after extraction demonstrated that calcification had formed over a hair.
PMCID: PMC2718097  PMID: 11752971
Urolithiasis; Bladder stone; Hair; Radiography
13.  Detection of Segmental Branch Renal Artery Stenosis by Doppler US: A Case Report 
Korean Journal of Radiology  2001;2(1):57-60.
In stenosis of a segmental branch or among multiple renal arteries, Doppler sampling of intrarenal arteries in the upper, mid and lower poles demonstrates strikingly different waveform patterns that might otherwise be overlooked. We report a case of segmental branch renal artery stenosis in which a pulsus parvus et tardus waveform was observed in a segmental branch of a renal artery. In this case, systematic analysis of Doppler waveforms of intrarenal arteries at more than three different locations facilitated a rapid and confident diagnosis of segmental branch renal artery stenosis.
PMCID: PMC2718096  PMID: 11752970
Renal arteries, stenosis or obstruction; Renal arteries, US; Ultrasound, Doppler studies
14.  Recurrent Uterine Cervical Carcinoma: Spectrum of Imaging Findings 
Korean Journal of Radiology  2000;1(4):198-207.
Uterine cervical carcinoma is one of the most common malignant tumors occurring in females. After primary treatment, patients are usually followed up with CT or MRI and the findings of these modalities may be the first sign of recurrent disease. Because earlier additional treatment by chemotherapy or radiation therapy may improve the prognosis, the early detection of recurrent cervical carcinoma is clinically important. In this article, we review the CT and MR imaging findings of recurrent uterine cervical carcinoma, and assign them to one of four groups: a) recurrence at the primary site, involving the intrapelvic organs, b) extension to the pelvic side-wall, c) metastases to pelvic and extrapelvic lymph nodes, or d) metastases to distant organs. A further contribution of CT and MR imaging is the detection of hydronephrosis due to ureteral obstruction. The cases in each group are illustrated and discussed, and since an awareness of the spectrum of imaging findings of recurrent cervical carcinoma is likely to lead to its early detection, radiologists should be familiar with the information presented.
PMCID: PMC2718201  PMID: 11752955
Uterine neoplasms, diagnosis; Uterine neoplasms, CT; Uterine neoplasms, MR
15.  Radiologic Findings of Renal Inflammatory Pseudotumor: A Case Report 
Korean Journal of Radiology  2000;1(4):219-222.
Renal inflammatory pseudotumor is a very rare benign condition of unknown etiology characterized by proliferative myofibroblasts, fibroblasts, histiocytes, and plasma cells. In the case we report, the lesion appeared on contrast-enhanced power Doppler US images as a well-defined hypoechoic mass with intratumoral vascularity, and on CT as a low-attenuated mass. Differentiation from malignant renal neoplasms was not possible.
PMCID: PMC2718205  PMID: 11752959
Kidney, neoplasms; Ultrasound (US)
16.  Effectiveness of MR Urography in the Evaluation of Kidney which Failed to Opacify during Excretory Urography: Comparison with Ultrasonography 
Korean Journal of Radiology  2000;1(3):152-158.
The purpose of this study was to compare the effectiveness of MR urography (MRU) with that of ultrasonography (US) in the evaluation of urinary tract when this failed to opacify during excretory urography (EXU).
Materials and Methods
Twelve urinary tracts in 11 patients were studied. In each case, during EXU, the urinary system failed to opacify within one hour of the injection of contrast media, and US revealed dilatation of the pelvocalyceal system. Patients underwent MRU, using a HASTE sequence with the breath-hold technique; multi-slice acquisition was then performed, and the images were reconstructed using maximal intensity projection. Each set of images was evaluated by three radiologists to determine the presence, level, and cause of urinary tract obstruction.
Obstruction was present in all twelve cases, and in all of these, MRU accurately demonstrated its level. In this respect, however, US was successful in only ten. The cause of obstruction was determined by MRU in eight cases, but by US in only six. In all of these six, MRU also successfully demonstrated the cause.
MRU is an effective modality for evaluation of the urinary tract when this fails to opacify during EXU, and appears to be superior to US in demonstrating the level and cause of obstruction.
PMCID: PMC2718184  PMID: 11752946
Kidney, obstruction; Kidney, MR; Kidney, US; Urography; Magnetic resonance (MR), comparative studies
17.  Increased urinary Angiotensinogen/Creatinine (AGT/Cr) ratio may be associated with reduced renal function in autosomal dominant polycystic kidney disease patients 
BMC Nephrology  2015;16:86.
Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common hereditary kidney diseases that frequently result in renal failure. In this cross-sectional observational cohort study, we evaluated urinary angiotensinogen (AGT) as a potential biomarker to assess renal function in ADPKD.
Urinary AGT was measured in 233 ADPKD patients and its association with estimated glomerular filtration rate (eGFR) and height-adjusted total kidney volume (htTKV) were evaluated. The localization of AGT and other renin-angiotensin system (RAS)-related molecules were identified using immunohistochemistry in human ADPKD tissues.
Baseline urinary AGT/Cr was negatively correlated with CKD-EPI eGFR (r2  = 0.162, P < 0.001) and positively correlated with htTKV (r2 = 0.107, P < 0.001). Both urinary AGT/Cr and plasma renin activity levels were significantly elevated in hypertensive ADPKD patients. Among hypertensive subjects, urinary AGT/Cr was significantly increased in the advanced CKD stages (III-V) compared to early CKD stages (I-II) (28.6 ± 60.3 vs. 93.2 ± 139.3 μg/g, P < 0.001). Immunohistochemical study showed strong expression of AGT along the cyst-lining epithelial cells as well as the nearby compressed tubular epithelial cells.
Our results suggested that urinary AGT/Cr may be a valuable biomarker for renal damage in ADPKD since intrarenal ischemic insults induced by cyst growth and subsequent intrarenal RAS activation may play a potential role in the development of hypertension and renal dysfunction in ADPKD.
Electronic supplementary material
The online version of this article (doi:10.1186/s12882-015-0075-8) contains supplementary material, which is available to authorized users.
PMCID: PMC4475321  PMID: 26092580
Angiotensinogen; Autosomal dominant polycystic kidney disease; Biomarkers; Renal function; Renin-angiotensin system
18.  Shear Wave Elastography for Detection of Prostate Cancer: A Preliminary Study 
Korean Journal of Radiology  2014;15(3):346-355.
To assess the diagnostic value of shear wave elastography (SWE) for prostate cancer detection.
Materials and Methods
In this retrospective study, 87 patients with the suspicion of prostate cancer (prostate-specific antigen > 4 ng/mL and abnormal digital rectal examination) underwent a protocol-based systematic 12-core biopsy followed by targeted biopsy at hypoechoic areas on grey-scale ultrasound. Prior to biopsy, SWE was performed by placing two circular 5 mm-sized regions of interest (ROIs) along the estimated biopsy tract in each sector and one ROI for hypoechoic lesions. SWE parameters, S (mean stiffness) and R (mean stiffness ratio), were calculated and compared regarding different histopathologic tissues and their accuracy for diagnosing prostate cancer was analyzed. SWE parameters were correlated with Gleason score and were compared between indolent (< 8) and aggressive (≥ 8) tissues in prostate cancer patients.
Prostate cancer was detected in 7.5% of 1058 cores in 29.9% of 87 patients. Seven (43.8%) of 16 hypoechoic lesions were confirmed as prostate cancer. SWE parameters were significantly different among the histopathologic entities (p < 0.001). Prostate cancer was stiffer than benign tissues (p ≤ 0.003). Sensitivity, specificity and receiver operating characteristic curve area for diagnosing cancer were 43%, 80.8%, and 0.599, respectively, for a cutoff of S > 43.9 kPa and 60.8%, 66.4%, and 0.653, respectively, for R > 3. Both, S and R showed a significant correlation with Gleason score (r ≥ 0.296, p ≤ 0.008) and were significantly different between indolent and aggressive prostate cancer (p ≤ 0.006).
Shear wave elastographic parameters are significantly different between prostate cancer and benign prostate tissue and correlate with Gleason score.
PMCID: PMC4023053  PMID: 24843239
Prostate cancer; Shear wave elastography; Young modulus; Ultrasonography; Gleason score
19.  Hyperuricemia and deterioration of renal function in autosomal dominant polycystic kidney disease 
BMC Nephrology  2014;15:63.
The role of hyperuricemia in disease progression of autosomal dominant polycystic kidney disease (ADPKD) has not been defined well. We investigated the association of serum uric acid (sUA) with renal function and the effect of hypouricemic treatment on the rate of renal function decline.
This is a single-center, retrospective, observational cohort study. A total of 365 patients with ADPKD who had estimated glomerular filtration rate (eGFR) ≥ 15 mL/min/1.73 m2 and who were followed up for > 1 year were included in our analysis. Hyperuricemia was defined by a sUA level of ≥ 7.0 mg/dL in male and ≥ 6.0 mg/dL in female or when hypouricemic medications were prescribed.
Hyperuricemia was associated with reduced initial eGFR, independent of age, sex, hypertension, albuminuria, and total kidney volume. During a median follow-up period of over 6 years, patients with hyperuricemia showed a faster annual decline in eGFR (−6.3% per year vs. −0.9% per year, p = 0.008). However, after adjusting for age, sex, hypertension and initial eGFR, sUA was no longer associated with either annual eGFR decline or the development of ESRD. Among 53 patients who received hypouricemic treatment, the annual eGFR decline appeared to be attenuated after hypouricemic treatment (pretreatment vs. posttreatment: −5.3 ± 8. 2 vs. 0.2 ± 6.2 mL/min/1.73 m2 per year, p = 0.001 by Wilcoxon signed-rank test).
Although hyperuricemia was associated with reduced eGFR, it was not an independent factor for renal progression in ADPKD. However, the correction of hyperuricemia may attenuate renal function decline in some patients with mild renal insufficiency.
PMCID: PMC4021172  PMID: 24739095
Glomerular filtration rate; Hyperuricemia; Polycystic kidney; Autosomal dominant; Uric acid
20.  Usefulness of resistive index on spectral Doppler ultrasonography in the detection of renal cell carcinoma in patients with end-stage renal disease 
Ultrasonography  2014;33(2):136-142.
The aim of this study was to explore the usefulness of the resistive index (RI) on spectral Doppler ultrasonography (US) in the detection of renal cell carcinoma (RCC) in patients with end-stage renal disease (ESRD).
Seventeen ESRD patients with kidneys in which renal masses were suspected in routine US were subjected. They underwent computed tomography scans and additional Doppler US for the characterization of the detected lesions. All underwent radical nephrectomy with the suspicion of RCC. Fourteen patients finally were included. RI measurements were conducted in the region of the suspected renal mass and the background renal parenchyma. The intraclass correlation coefficient was used to assess the reproducibility of the RI measurement. A paired t-test was used to compare the RI values between the renal mass and the background renal parenchyma (P<0.05).
The RI values measured at the RCCs were significantly lower than those measured at the background renal parenchyma (0.41-0.65 vs. 0.75-0.89; P<0.001). The intrareader reproducibility proved to be excellent and good for the renal masses and the parenchyma, respectively (P<0.001).
RI on spectral Doppler US is useful in detecting RCC in patients with ESRD. The RI values measured at the RCCs were significantly lower than those measured at the background renal parenchyma.
PMCID: PMC4058981  PMID: 24936507
Ultrasonography, Doppler, pulsed; Ultrasonography, Doppler, color; Kidney failure, chronic; Carcinoma, renal cell
21.  Magnetic Resonance Evaluation of Müllerian Remnants in Mayer-Rokitansky-Küster-Hauser Syndrome 
Korean Journal of Radiology  2013;14(2):233-239.
To analyze magnetic resonance imaging (MRI) findings of Müllerian remnants in young females clinically suspected of Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome in a primary amenorrhea workup.
Materials and Methods
Fifteen young females underwent multiplanar T2- and transverse T1-weighted MRI at either a 1.5T or 3.0T MR imager. Two gynecologic radiologists reached consensus decisions for the evaluation of Müllerian remnants, vagina, ovaries, and associated findings.
All cases had bilateral uterine buds in the pelvic cavity, with unilateral cavitation in two cases. The buds had an average long-axis diameter of 2.64 ± 0.65 cm. In all cases, bilateral buds were connected with fibrous band-like structures. In 13 cases, the band-like structures converged at the midline or a paramedian triangular soft tissue lying above the bladder dome. The lower one-third of the vagina was identified in 14 cases. Fourteen cases showed bilateral normal ovaries near the uterine buds. One unilateral pelvic kidney, one unilateral renal agenesis, one mild scoliosis, and three lumbar sacralization cases were found as associated findings.
Typical Müllerian remnants in MRKH syndrome consist of bilateral uterine buds connected by the fibrous band-like structures, which converge at the midline triangular soft tissue lying above the bladder dome.
PMCID: PMC3590335  PMID: 23483587
Amenorrhea; Magnetic resonance imaging; Mayer-Rokitansky-Küster-Hauser syndrome; Müllerian; Remnant
22.  Immunoglobulin G4-Related Sclerosing Disease Involving the Urethra: Case Report 
Korean Journal of Radiology  2012;13(6):803-807.
Immunoglobulin G4 (IgG4)-related sclerosing disease is a systemic disease characterized by extensive IgG4-positive plasma cells and T-lymphocyte infiltration in various organs. We described the imaging findings of an IgG4-related inflammatory pseudotumor in the urethra. The urethral mass showed isoattenuation on unenhanced CT images, delayed enhancement on enhanced CT images, iso- to slight hyper-intensity on T1 and T2 weighted magnetic resonance images, diffusion restriction on diffusion weighted images, and heterogeneously low echogeneity on ultrasonography.
PMCID: PMC3484302  PMID: 23118580
Immunoglobulin G4-related sclerosing disease; Inflammatory pseudotumor; Urethra; IgG4
23.  Urinary N-acetyl-β-D glucosaminidase as a surrogate marker for renal function in autosomal dominant polycystic kidney disease: 1 year prospective cohort study 
BMC Nephrology  2012;13:93.
Renal failure is one of the most serious complications associated with autosomal dominant polycystic kidney disease (ADPKD). To date, early markers have failed to predict renal function deterioration at the early stages. This 1-year prospective study evaluated N-acetyl-β-D-glucosaminidase (NAG) as a new surrogate marker for renal function in ADPKD.
A total of 270 patients were enrolled in the study, and we measured urinary NAG, β2-microglobulin, neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) prospectively for 1 year to compare their predictive values for renal function.
Baseline urinary NAG/Cr was negatively correlated with estimated glomerular filtration rate (GFR) (r2 = 0.153, P < 0.001) and positively correlated with total kidney volume (TKV) (r2 = 0.113, P < 0.001). Among other biomarkers, urinary NAG/Cr better discriminated patients with decreased renal function from those with conserved renal function, showing the largest area under the curve (AUC 0.794). Immunohistochemical study revealed strong staining along the cyst-lining epithelial cells as well as the nearby compressed tubular epithelial cells. However, both single and repeated measurements of urinary NAG/Cr failed to predict renal function decline in 1 year.
Urinary NAG/Cr may be a useful surrogate marker for renal function in ADPKD patients.
PMCID: PMC3465238  PMID: 22935351
Autosomal dominant polycystic kidney disease; Biomarkers; Renal function
24.  Nonfunctioning Periurethral Paraganglioma Incidentally Detected by FDG PET/CT 
Paragangliomas are extra-adrenal neuroendocrine tumors that are derived from neural crest cells. Among all the paragangliomas, those in a pelvic location are extremely rare. In addition, the prevalence of nonfunctioning paragangliomas is underestimated because of their clinical latency, and they are often underdiagnosed unless they cause symptoms. We report a case of a nonfunctioning periurethral paraganglioma that was incidentally detected by FDG PET/CT during regular follow-up after excision of a melanoma on the left thumb.
PMCID: PMC4043015  PMID: 24899994
Nonfunctioning periurethral paraganglioma; Extra-adrenal pheochromocytoma; FDG PET/CT
25.  Intratumoral Heterogeneous F-18 Fluorodeoxyglucose Uptake Corresponds with Glucose Transporter-1 and Ki-67 Expression in a Case of Krukenberg Tumor: Localization of Intratumoral Hypermetabolic Focus by Fused PET/MR Image 
The expression of glucose transporters (Glut-1, Glut-3), hexokinase-II, and Ki-67 has been proposed to explain intratumoral heterogeneous F-18 fluorodeoxyglucose (FDG) uptake. We report a case of Krukenberg tumor with intratumoral heterogeneous FDG uptake which corresponded well with the expression levels of Glut-1 and ki-67. Fused positron emission tomography (PET)/magnetic resonance (MR) imaging was helpful for localizing the metabolically active area in the tumor specimen. This report elucidates the relationship between the intratumoral heterogeneous FDG uptake and biologic heterogeneity, and shows the usefulness of PET/MR in research on intratumoral heterogeneity.
PMCID: PMC4043022  PMID: 24899993
FDG; PET/CT; PET/MRI; Glut-1; Ki-67; Krukenberg tumor

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