• Korean Journal of Radiology
• /
• v.23 no.10
• /
• pp.1019-1027
• /
• 2022

Objective: Thyroidectomy bed lesions frequently show suspicious ultrasound (US) features after thyroid surgery. Fine-needle aspiration (FNA) may not provide definitive pathological information about the lesions. Although core-needle biopsy (CNB) has excellent diagnostic performance in characterizing suspicious thyroid nodules, no published studies have evaluated the performance of CNB specifically for thyroidectomy bed lesions. Therefore, we aimed to evaluate the diagnostic performance and safety of CNB for characterizing thyroidectomy bed lesions. Materials and Methods: A total of 124 thyroidectomy bed lesions in 113 patients (79 female and 34 male; age, 23-85 years) who underwent US-guided CNB between December 2008 and December 2020 were included. We reviewed the US imaging features of the target lesions and the histories of previous biopsies. The pathologic results, diagnostic performance for malignancy, and complications of CNB were analyzed. Results: All samples (100%) obtained by CNB were adequate for pathological analysis. Pathological analysis revealed inconclusive results in two lesions (1.6%). According to the reference standard, 50 lesions were ultimately malignant (40.3%), and 72 were benign (58.1%), excluding the two inconclusive lesions. The performance of CNB for diagnosing malignant thyroidectomy bed lesions in the 122 lesions had a sensitivity of 98.0% (49/50), a specificity of 100% (72/72), positive predictive value of 100% (49/49), and negative predictive value of 98.6% (72/73). Eleven lesions were referred for CNB after prior inconclusive FNA results in thyroidectomy bed lesions, for all of which CNB yielded correct conclusive pathologic diagnoses. According to the pathological analysis of CNB, there were various benign lesions (58.9%, 73/124) besides recurrence, including benign postoperative lesions other than suture granuloma (32.3%, 40/124), suture granuloma (15.3%, 19/124), remnant thyroid tissue (5.6%, 7/124), parathyroid lesions (4%, 5/124), and abscesses (1.6%, 2/124). No major or minor complications were associated with the CNB procedure. Conclusion: US-guided CNB is accurate and safe for characterizing thyroidectomy bed lesions.

• Korean Journal of Radiology
• /
• v.21 no.4
• /
• pp.431-441
• /
• 2020

Objective: To compare the diagnostic performance and interobserver variability of strain ratio obtained from one or two regions of interest (ROI) on breast elastography. Materials and Methods: From April to May 2016, 140 breast masses in 140 patients who underwent conventional ultrasonography (US) with strain elastography followed by US-guided biopsy were evaluated. Three experienced breast radiologists reviewed recorded US and elastography images, measured strain ratios, and categorized them according to the American College of Radiology breast imaging reporting and data system lexicon. Strain ratio was obtained using the 1-ROI method (one ROI drawn on the target mass), and the 2-ROI method (one ROI in the target mass and another in reference fat tissue). The diagnostic performance of the three radiologists among datasets and optimal cut-off values for strain ratios were evaluated. Interobserver variability of strain ratio for each ROI method was assessed using intraclass correlation coefficient values, Bland-Altman plots, and coefficients of variation. Results: Compared to US alone, US combined with the strain ratio measured using either ROI method significantly improved specificity, positive predictive value, accuracy, and area under the receiver operating characteristic curve (AUC) (all p values < 0.05). Strain ratio obtained using the 1-ROI method showed higher interobserver agreement between the three radiologists without a significant difference in AUC for differentiating breast cancer when the optimal strain ratio cut-off value was used, compared with the 2-ROI method (AUC: 0.788 vs. 0.783, 0.693 vs. 0.715, and 0.691 vs. 0.686, respectively, all p values > 0.05). Conclusion: Strain ratios obtained using the 1-ROI method showed higher interobserver agreement without a significant difference in AUC, compared to those obtained using the 2-ROI method. Considering that the 1-ROI method can reduce performers' efforts, it could have an important role in improving the diagnostic performance of breast US by enabling consistent management of breast lesions.

• Childhood Kidney Diseases
• /
• v.8 no.2
• /
• pp.223-228
• /
• 2004

Purpose and Methods: Urinary tract infection(UTI) is one of the most important diseases of childhood, especially for young infants. To characterize the patients diagnosed with febrile UTI in their first 6 months of life and to explore the risk factors of recurrent UTI, a retrospective study was performed. Results: Among the 90 patients studied, 77 were boys(86%). First episodes of UTI were diagnosed at the age of $2.5{\pm}1.4$ months. These patients underwent ultrasonographic evaluation of urinary tract(n=90) and voiding cystourethrography(n=81) where 53 and 35 studies showed abnormal findings respectively, and a total of 45 cases of urinary tract anomaly including vesicoureteral reflux(VUR, n=35) were diagnosed. Normal findings on ultrasonography indicated decreased risk of VUR in boys of 1-3 months of age(n=30). 53 patients were followed up more than 6 months and 45 episodes of subsequent UTI developed in 29 patients during the first 6-month period. Patients with relapse were older than patients without relapse at the diagnosis of first UTI, but other clinical parameters including abnormal findings on the imaging studies and prophylactic antibiotics prescription were not different between the two groups. Conclusion: UTI in early infancy occurred mainly in male infants and half of the patients had structural anomalies. USG was of clinical value in detecting anomalies requiring surgical intervention, and to rule out high grade VUR in 1-3 months old boys. Results of the imaging study or prophylactic antibiotics could not modify the risk of recurrent UTI. (J Korean Soc Pediatr Nephrol 2004;8:223-228)

• Clinical and Experimental Pediatrics
• /
• v.45 no.4
• /
• pp.466-472
• /
• 2002

Purpose : The diagnosis of Meckel's diverticulum is difficult and delayed because it presents with various clinical symptoms. We evaluated clinical, imaging and pathologic findings of Meckel's diverticulum to facilitate detection of Meckel's diverticulum in children. Methods : Review of clinical, imaging, surgical and pathological findings in 10 children aged 7 days to 14 years with Meckel's diverticulum during an 8-year period, 1993-2001, at Ewha Womans University Hospital was undertaken. Results : The male to female ratio was 2.3 : 1. The chief complaint was painless lower gastrointestinal( GI) bleeding; others were abdominal pain, abdominal distention and vomiting, in order of frequency. The diagonsis before surgery were Meckel's diverticulum in 5 patients, non-reducible intussusception in 3 patients and intestinal obstruction in 2 patients. The diverticulum was located between 35 cm to 70 cm proximal to the ileocecal valve. The length of the diverticulum ranged from 4 cm to 12 cm and 80% of it was within 5 cm. A Meckel scan($^{99m}Tc-pertechnetate$ scintigraphy) after cimetidine administration was done in 6 cases. All 5 cases that presented with lower GI bleeding had ectopic gastric mucosa confirmed on pathology. Out of 5 cases of ectopic gastric mucosa, only 4 cases were positive on the Meckel's scan. Conclusion : In cases of unexplained GI bleeding, obstruction, or inflammation diagnostic workup should be carried out to rule out Meckel's diverticulum. Laparoscopy, high resolution ultrasonography and computed tomography of the abdomen may be indicated in the assessment of pediatric patient with lower GI bleeding, especially in patients with suspected bleeding from Meckel's diverticulum showing negative Meckel's scan.

• Childhood Kidney Diseases
• /
• v.14 no.1
• /
• pp.42-50
• /
• 2010

Purpose : The clinical characteristics and associated anomalies in children with solitary kidney (SK) were analyzed retrospectively. Methods : Total 38 children diagnosed to have SK at our hospital between December 1989 and December 2009 were recruited, and the clinical records including imaging studies were retrospectively reviewed. SK was defined as unilateral renal agenesis by imaging studies only, and patients with regression of unilateral dysplastic kidney were excluded. Results : Among total 38 patients, 12 were male. The median age at the diagnosis of SK was 6.5 months (at birth-13 years). SK was detected by prenatal ultrasonography in 14 patients and during work-up for renal or urinary tract diseases in 13 (including urinary tract infection in 7). In 10 patients, SK was detected incidentally. Anomalies in the SK were noted in 17 patients including vesicoureteral reflux in 11. Other anomalies in the genitourinary tract were present in 16 patients, and multi-organ-involving syndromes or chromosomal anomalies were detected in 9. The mean duration of follow-up was 9 years (9 months-20 years). Two patients developed chronic renal failure during follow-up, and the median serum creatinine concentration of the remaining 36 at their last follow-up was 0.6 mg/dL. Conclusion : SK may be isolated and clinically asymptomatic; it is frequently accompanied by other anomalies in genitourinary tract and other organs, some of which can induce progressive renal dysfunction. Early recognition of associated anomalies with SK and regular follow-up is recommended to reduce long-term risk.

• Ultrasonography
• /
• v.32 no.1
• /
• pp.59-65
• /
• 2013

Purpose: The purpose of this study is to establish the methodology regarding synthesis of ultrasound contrast agent imaging, and to evaluate the characteristics of the synthesized ultrasound contrast agents, including size or degradation interval and image quality. Materials and Methods: The ultrasound contrast agent, composed of liposome and SF6, was synthesized from the mixture solution of $21{\mu}mol$ DPPC (1, 2-Dihexadecanoyl-sn-glycero-3-phosphocholine, $C_{40}H_{80}NO_8P$), $9{\mu}mol$ cholesterol, $1.9{\mu}mol$ of DCP (Dihexadecylphosphate, $[CH_3(CH_2)_{15}O]_2P(O)OH$), and chloroform. After evaporation in a warm water bath and drying during a period of 12-24 hours, the contrast agent was synthesized by the sonication process by addition of buffer and SF6 gas. The size of the contrast agent was controlled by use of either extruder or sonication methods. After synthesis of contrast agents, analysis of the size distribution of the bubbles was performed using dynamic light scattering measurement methods. The degradation curve was also evaluated by changes in the number of contrast agents via light microscopy immediate, 12 hours, 24 hours, 36 hours, 48 hours, 60 hours, 72 hours, and 84 hours after synthesis. For evaluation of the role as an US contrast agent, the echogenicity of the synthesized microbubble was compared with commercially available microbubbles (SonoVue, Bracco, Milan, Italy) using a clinical ultrasound machine and phantom. Results: The contrast agents were synthesized successfully using an evaporation-drying-sonication method. The majority of bubbles showed a mean size of 154.2 nanometers, and they showed marked degradation 24 hours after synthesis. ANOVA test revealed a significant difference among SonoVue, synthesized contrast agent, and saline (p < 0.001). Although no significant difference was observed between SonoVue and the synthesized contrast agent, difference in echogenicity was observed between synthesized contrast agent and saline (p < 0.01). Conclusion: We could synthesize ultrasound contrast agents using an evaporation-drying-sonication method. On the basis of these results, many prospective types of research, such as anticancer drug delivery, gene delivery, including siRNA or microRNA, targeted molecular imaging, and targeted therapy can be performed.

• Journal of the Korean Applied Science and Technology
• /
• v.36 no.3
• /
• pp.1028-1040
• /
• 2019

The current study was performed to investigate the magnitude of exercise-induced muscle damage (EIMD) after downhill running (DR) of different intensities and to examine the availability of muscle echo intensity as biomarkers to detect regional damage within quadriceps muscle group (QG) following DR. Healthy college-age men (n=11) were experienced twice DR sessions [$50%HR_{max}$ DR, LDR; $70%HR_{max}$ DR, HDR] separated by a 2-week wash-out period with the random order. After DR, severity of EIMD according to exercise intensity were determined by serum creatine kinase (CK) activity, muscle tenderness, and neuromuscular function indicators such as a maximal voluntary isometric contraction (MVIC) and range of motion (ROM). Transvaginal B-mode imaging had been employed to evaluate regional muscle echo intensity within QG [rectus femoris, RF; vastus lateralis, VL; vastus medialis, VM; vastus intermedius, VI]. After both DR sessions, changes in serum CK activity and muscle tenderness have tended to more increase in HDR compared to those of LDR. There was a significant interaction effect between exercise intensity during DR and the time course of serum CK activity(p<.05). However, there were no statistical differences between sessions in muscle tenderness. The time course of changes in the neuromuscular functions after DR were similar to those of regional muscle echo intensity regardless exercise intensity. Although neuromuscular function showed to decline in HDR more than those of LDR after DR, no statistical differences between sessions. In contrast, there were significant interaction effects between sessions and time course of changes in RF and VL muscle echo intensity(p<.01), but not shown in those of VI and VM. These results indicated that each muscles within the QG show different response profiles for EIMD during DR, exercise intensity influences on these responses as well. In particular, current findings suggested that muscle echo intensity derived from ultrasound imaging is capable of detecting regional muscle damage in QG following DR.

• Advances in pediatric surgery
• /
• v.4 no.2
• /
• pp.149-155
• /
• 1998

Thirty three members of the Korean Association of Pediatric Surgeons were surveyed to determine the clinical manifestations and current management of infantile hypertrophic pyloric stenosis (IHPS). The members completed a registration form and a questionnaire that indicated their treatment preferences for patients treated during 1996. The response rate was 84.8 %, and 23 institutions participated. Three hundred and sixty-three cases of IHPS were analysed. The male to female ratio was 5.15: 1. The presenting symptoms were nonbilious vomiting in 363 cases(100 %), palpable mass in the upper abdomen in 200 cases (55.1 %) and visible peristaltic waves in 67 cases(18.5 %). Fluid therapy was done in 161 cases(44.4 %) for preoperative preparation. Twenty patients(5.5 %) were premature. There were 27 low birth weight babies(7.7 %). The onset of symptoms ranged from 1 to 14 weeks of age with a peak occurrence at 2 to 4 weeks of age. Two hundred and thirty-six cases(66.6 %) presented within 4 weeks of age. There was one set of male twins and a family history of twins. The modes of feedings were: breast feeding; 69 cases(24.5 %), formula feeding; 176 cases(62.4 %) and mixed feeding; 37 cases(13.1 %). The preferred diagnostic modalities were ultrasonography (US) 229 cases(63.1 %), UGI series 27 cases(7.4%) and US and UGI series combined 86 cases(23.7 %). Only 21 cases(5.8 %) were operated on without imaging study, ie. with positive physical finding. Perforation of the mucosa during pyloromytomy occurred in 5 cases. All were treated successfully with primary closure. Persistent vomiting over 2 weeks after operation were reported in 5 cases. Three wound infections, one aspiration pneumonia and one postoperative bleeding were reported. There was no mortality in 363 cases.

• Clinical and Experimental Pediatrics
• /
• v.45 no.2
• /
• pp.232-239
• /
• 2002

Purpose : Renal cystic diseases comprise a mixed group of heritable, developmental and acquired disorders. Recently the use of imaging modalities such as ultrasonography and radionuclide scanning has increased the detection rate of renal cystic diseases. We studied to review the clinical features and treatment of renal cystic diseases in children. Methods : This study was performed in 95 children with renal cystic diseases in the Department of Pediatrics, Asan Medical Center from October 1989 to June 2001. Results : In 95 patients, there were 55 cases(58.0%) with multicystic dysplastic kidney(MCDK), 19 cases(20.0%) with simple renal cysts, 13 cases(13.7%) with hereditary polycystic kidney diseases( 7 with autosomal recessive type, 5 with autosomal dominant type, 1 with undetermined), 6 cases(6.3%) with renal cysts in tuberous sclerosis and 1 case(1.0%) with medullary cystic disease. All MCDK patients had no renal dysfunction and hypertension during the follow-up period. Three out of 13 with polycystic kidney diseases had progressed to end-stage renal disease during the follow-up period. One case with a simple cyst underwent laparoscopic malsupialization for decompression. Conclusion : Renal cystic diseases have diverse clinicopathologic features and variable prognosis. We emphasize that routine follow-up should be performed to prevent and to detect early treatable complication in renal cystic diseases. Therefore, their natural history and treatment need further investigation and long term follow-up is required.

• Investigative Magnetic Resonance Imaging
• /
• v.9 no.2
• /
• pp.109-116
• /
• 2005

Purpose : To determine the usefulness of additional Mn-DPDP MRI for preoperative evaluation of the patients with colorectal cancers by comparison of dual-phase CT scan, Mn-DPDP enhanced MRI and combination of CT and MRI. Materials and Methods : Fifty-three colorectal cancer patients with 92 metastatic nodules underwent dualphase (arterial and portal) helical CT scan and Mn-DPDP MRI prior to surgery. The indication of MRI was presence or suspected of having metastatic lesions at CT scan and/or increased serum carcinoembryonic antigen (CEA) levels (10 ng/mL or more). The diagnosis was established by the combination of findings at surgery, intraoperative ultrasonography, and histopathologic examination. Two radiologists interpreted CT, MRI, and combination of CT-MRI at discrete sessions and evaluated each lesion for location, size, and intrinsic characteristics. The lesions were divided into three groups according to their diameter; 1cm<, 1-2 cm, and >2 cm. Diagnostic accuracy was evaluated using the alternative-free response receiver operating characteristic method. Detection and false positive rate were also evaluated. Results : In the lesions smaller than 1 cm, detection rate of combined CT-MRI was superior to CT or MRI alone (82%, p=0.036). The mean accuracy (Az values) of combined CT and MRI was significantly higher than that of CT in the lesions smaller than 2 cm (1 cm<, p=0.034; 1-2 cm, p=0.045). However, there was no significant difference between MRI and combined CT-MRI. The false positive rate of CT was higher than those of combined CT-MR in the lesions smaller than 1 cm (28%, p=0.023). Conclusion : Additional MRI using Mn-DPDP besides routine CT scan was helpful in differentiating the hepatic lesions (<2 cm) and could improve detection of the small hepatic metastases (<1 cm) from colorectal carcinoma.